JP2015127364A - Nanodiamond containing composite and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a method for producing a composition comprising at least one filler and nanodiamond material; and a composition comprising at least one filler and nanodiamond material.SOLUTION: A method for producing a composition comprising at least one filler and nanodiamond material comprises (i) bringing a nanodiamond material-containing liquid medium into contact with the at least one filler for producing a suspension, and (ii) removing the liquid medium from the suspension of the step (i) for producing the composition comprising the at least one filler and the nanodiamond material.

Description

  The present invention relates to a method for producing a composition comprising at least one filler and a nanodiamond material, and to a composition comprising a nanodiamond material and at least one filler. The present invention further relates to a method for producing a nanodiamond-containing thermal composite and a nanodiamond-containing thermal composite comprising a nanodiamond material, at least one filler and at least one polymer.

  Nanodiamond (ND), also called ultra-nanocrystalline diamond or ultradispersed diamond (UDD), is a special nanomaterial that can produce hundreds of kilograms by detonation synthesis. These nanodiamonds are called detonated nanodiamonds.

  Synthetic nanodiamond can be produced by several known methods (for example, chemical vapor deposition and high pressure).

  Detonated nanodiamonds were first synthesized by researchers in the Soviet Union in 1963 by explosively decomposing a highly explosive mixture in an oxygen-deficient state in a non-oxidizing medium. A typical explosive mixture is a mixture of trinitrotoluene (TNT) and hexogen (RDX), with a preferred TNT / RDX weight ratio of 40/60.

  As a result of detonation synthesis, a soot containing diamond (also called detonation mixture) is obtained. This mixture consists of nanodiamond particles with a typical average particle size of about 2 to 8 nm, and various types of non-contaminated materials with metal and metal oxide particles derived from detonation chamber materials and explosives used. Contains diamond carbon. A typical value for the content of nanodiamond contained in the detonation mixture is 30-75% by weight.

  The nanodiamond-containing mixture obtained by detonation contains a plurality of identical hard masses with a typical value of diameter exceeding 1 mm. Such lumps are difficult to break. In addition, the particle size distribution of the mixture is very wide, generally extending over tens of microns.

Diamond carbon includes sp ³ carbon, and non-diamond carbon mainly includes sp ² carbon species (eg, carbon onion, carbon fullerene shell, amorphous carbon, graphite carbon, or any combination thereof).

  There are many ways to purify detonation mixtures. The purification step is considered to be the most complex and most expensive step in the production of nanodiamonds.

  In order to separate the final diamond-containing product, a combination of chemical operations is used to dissolve or vaporize impurities present in the material. There are generally two types of impurities. That is, non-carbon (metal oxide, salt, etc.) and carbon in a form different from diamond (graphite, carbon black, amorphous carbon).

  The chemical purification technique is based on the fact that diamond form carbon and non-diamond form carbon have different stability to oxidants. Liquid phase oxidants are advantageous over gaseous or solid systems. This is because the liquid-phase oxidant can increase the concentration of reactants in the reaction region, and thus increase the reaction rate.

  In recent years, detonation nanodiamonds have been pre-existing in plating (both electroplating and electroless plating), polishing, various mechanical and thermal composites made of polymers, CVD seeds, oils and lubricant additives In addition to several applications, there is an increasing interest due to the possible new applications such as fluorescence imaging, drug delivery and quantum engineering. The availability of detonation nanodiamonds is based on the outer surface of detonation nanodiamonds being covered with various surface functional groups, unlike nanodiamonds derived from micron-sized diamonds, for example by grinding and sieving.

  Recently, the use of nanodiamonds in polymers to manage heat has been studied.

  For example, it is necessary to improve reliability and prevent premature failure by dissipating heat generated in electronic devices and electronic circuits. As heat dissipation techniques, heat sinks, air cooling fans, and other forms of cooling, such as liquid cooling, are possible. The heat sink can be made of a metal or ceramic material depending on the application, but sometimes it can also be made of a polymer material. The latter is typically used to construct thermal greases such as silicone and epoxide, which are thermal interface materials, and to bond the circuit into the device structure itself. For example, when housing such devices, thermoplastic thermal composites are also used for thermal management of the entire device. Polycarbonate and silicone are also used as LED encapsulants. This is also an area where more efficient thermal management is increasingly an issue. In general, thermoplastic materials are thermoset materials such as silicones in so-called secondary polymer based heat sinks and thermal interface materials (TIM) (also called primary polymer based heat sinks). Used.

  The increased use of polymeric materials is based on the simple fact of reducing device weight and cost. Furthermore, since the thermally conductive plastic generally has a smaller coefficient of thermal expansion (CTE) than, for example, aluminum, stress due to the difference in expansion can be reduced. This is because the plastic CTE is closer to the silicon or ceramic CTE in contact with the plastic. Changes in the contact state between the thermal compound and the silicon / ceramic surface will adversely affect device function and lifetime. Since the polymer composite also has a degree of design freedom regarding the molding function and component integration, costly post-processing can be eliminated. However, the use of polymer materials is limited by its original heat transfer properties. This is because the typical value of thermal conductivity is only about 0.2 W / m · K.

  For example, miniaturization of electronic chips has become an important theme in the development of integrated circuits. Because electronic devices are smaller in size and faster in operation, how to dissipate the heat generated by the electronic devices to maintain the operational performance and stability of the electronic devices in operation. It is one point in research.

  Several methods have been proposed to improve the thermal conductivity properties of polymers. When preparing a thermal solution that also provides electrical insulation, current solutions include various ceramic particles (eg, alumina, hexagonal boron nitride, cubic boron nitride, aluminum nitride, carbides (eg, carbonized). Based on the use of boron). Solutions with simultaneous thermal and electrical insulation include various forms of graphite and amorphous carbon (eg graphite, graphene, carbon fiber, pyrolytic carbon, carbon nanotubes, micron diamonds, micron size diamonds). Nanodiamond obtained by grinding and sieving) is used as a hot filler. Even if metal particles (silver particles of various sizes) are used, a highly efficient thermal management method can be easily obtained.

  If the filler material to be added cannot be evenly distributed in the polymer matrix and forms large lumps in the resulting matrix, the use of the additive will still provide mechanical properties as in the original polymer material first. The thermal characteristics may be inferior. As this problem becomes more and more serious, the total content of various fillers in existing polymer composites is increasing. Further, as the content of various inorganic particles or metal particles increases, the cost of the compound increases, the wear of the treatment tool used increases, and the weight of the generated compound increases.

  The heat conductivity of the polymer heat sink depends not only on the thermal conductivity of the material used, but also on the boundary between the parent polymer and the hot particle surface to be added. The intervening wetting or coupling effect greatly affects the thermal conductivity of the accepted compound. In particular, current ceramic fillers and metal fillers exhibit significantly inert surface properties that can impair the effect of wetting or coupling to the parent polymer and adversely affect the thermal conductivity of the accepted compound. Generally known.

  In general, thermal conductivity is measured in both the in-plane direction and the through-plane direction of the material. The in-plane direction thermal conductivity is usually larger than the in-plane direction thermal conductivity. In general, anisotropic fillers (eg hexagonal boron nitride, graphite) are used to improve in-plane thermal conductivity, improving both in-plane and through-plane thermal conductivity. For this purpose, an isotropic spherical filler (for example, alumina particles) is used. The filler to be used is selected according to the needs in the application.

  The in-plane direction thermal conductivity and the in-plane direction thermal conductivity can be obtained by a laser flash method. Another method of measuring thermal conductivity is the hot disk method, which only determines the average thermal conductivity value.

  The electrical properties of the thermal composite can be adjusted by selecting a dielectric or conductive filler. In general, for the penetration of phonons throughout the thermal complex, the total content of additives is very high, starting from 20% but exceeding 80%. Some of the most advanced thermal composites can contain some of the above fillers.

  There is an upper limit to current thermal conductivity. Further, since the content of the filler is already extremely high, it is difficult to further improve. If the filler content is too high, other important properties (eg mechanical properties and weight) of the polymer composite are impaired. When the filler loading exceeds a certain value, the polymer used loses its wetting ability and the compound breaks down into powder or fragmented fragments.

  Accordingly, attempts have been made to improve the thermal conductivity of polymer composites by replacing part of the filler material with nanodiamonds.

  US Patent Application Publication 2010/0022423 A1 discloses the use of nanodiamonds to improve thermal conductivity in polymer materials (polymer greases). The nanodiamond thermal grease includes nanodiamond powder, thermal powder, and a substrate. Nanodiamond powder has a volume ratio of 5% to 30%, hot powder 40% to 90%, and substrate 5% to 30%.

  The polymer grease disclosed in US Patent Application Publication No. 2010/0022423 A1 has a high content of nanodiamonds and hot powder (filler), and a low content of substrate. Since the filler and nanodiamond contents are higher than the substrate content, the disadvantage of having a high filler content still exists.

  United States Patent Application Publication 2010/0022423 A1 further discloses a method for producing nanodiamond thermal grease. The substrate is first heated and then the nanodiamond powder is incorporated into the preheated substrate. The nanodiamond powder is dispersed in the substrate using a dispersant. A hot powder is incorporated into the substrate and nanodiamond mixture and the mixture is mixed to form a nanodiamond thermal grease.

  United States Patent Application Publication 2013/0206273 A1 discloses a polymer matrix nanocomposite and a method for producing the nanocomposite. Nanoparticles (eg, nanodiamonds) are made into a solution or dispersion and sprayed or coated onto a polymer resin matrix or mechanically dispersed. The nanoparticles may be mixed with filler particles (eg mica or carbon black). Mixing and dispersion of the filler and the polymer resin can be realized by methods such as extrusion, shear mixing, and 3-roll pulverization.

  With the methods of US Patent Application Publication Nos. 2010/0022423 A1 and 2013/0206273 A1, it is difficult to uniformly distribute the nanodiamond particles and the filler in the polymer matrix. If the distribution is not uniform, the thermal conductivity and mechanical properties will be inferior.

  H. Ebadi-Dehaghani, M. Nazempour, “Thermal conductivity of nanoparticle-filled polymers”, Smart Nanoparticles Technologies, 2012, pp. 519-540 discusses the thermal conductivity of polymers filled with nanoparticles. . It is disclosed in this publication that the thermal conductivity of polymers filled with nano-sized filler materials (eg graphite, boron nitride, carbon nanotubes) is improved. However, this publication does not mention nanodiamond as a filler material to improve the thermal conductivity of the polymer.

  Based on the above, there is a need for nanodiamond-containing thermal composites that preferably improve thermal conductivity but do not compromise other important properties. It has been recognized that there is a need to reduce the overall weight of the thermal composite and reduce the wear on the processing tool used to make the composite. In addition, solutions that are particularly applicable to automobiles and other means of transportation require at the same time improving the mechanical properties of the composite produced. In addition, automobiles and other means of transportation are supplied with electricity, so the polymer thermal compounds within them are becoming increasingly important. In the automotive field, there is a need to find solutions, particularly for E-drives and the batteries used.

  In preferred cases, the nanodiamond-containing thermal composite should have the same or improved thermal properties while reducing the overall manufacturing cost of the composite. Therefore, it must be possible to use a nanodiamond-containing thermal composite with significantly less nanodiamond added.

  Furthermore, there is a need to improve the process for producing nanodiamond-containing thermal composites with improved thermal conductivity. Nanodiamond-containing thermal composites must be easy and inexpensive to manufacture and must be easily applicable to a variety of thermal applications.

  The present invention relates to the method of claim 1 for producing a composition comprising at least one filler and a nanodiamond material.

  The invention further relates to the method of claim 17 for producing nanodiamond comprising a thermal composite.

  The present invention further relates to the composition of claim 33 comprising nanodiamond and at least one filler.

  In addition, the present invention relates to the nanodiamond-containing thermal composite of claim 47 comprising a nanodiamond material, at least one filler, and at least one polymer.

  Surprisingly, the thermal properties are obtained by contacting a dispersion or suspension containing nanodiamond with a filler, removing the liquid medium from the resulting suspension and mixing the resulting composition with a polymer. It has been found that nanodiamond-containing thermal composites with improved (for example, in-plane thermal conductivity and through-plane thermal conductivity) can be obtained.

  The improved thermal properties are achieved by contacting the nanodiamond-containing dispersion or solution with the filler material and then removing the liquid medium by multiple steps of the method of the present invention so that the nanodiamond material is applied to the surface of the filler material. This results from a composition that adheres and functions as a coupling agent between the filler material and the parent polymer. Such a coupling effect is made available by functionalization of the nanodiamond surface adapted to both the filler material and the parent polymer.

  Surprisingly now, both positively and negatively charged nanodiamond material particles (eg, amino-functionalized nanodiamond particles or carboxylic acid-functionalized nanodiamond particles), such as hexagonal boron nitride with negative zeta potential, It has been found that lumps form on the surface of the filler particles. This phenomenon was surprisingly seen even to a lesser extent with the less polar nanodiamond particles terminated with hydrogen.

  Surprisingly, using nanodiamond-containing mixed materials, including nanodiamonds embedded in a matrix of graphite and amorphous carbon, can also form lumps on the surface of filler particles such as graphite, between the filler material and the parent polymer. It has been found that a coupling effect occurs. This effect can be finely tuned by selecting the surface functionalization of the nanodiamond material used (including both surface functionalized nanodiamonds and graphite and amorphous surface functionalized matrices).

  The nanodiamond-containing thermal composite of the present invention transfers thermal energy more efficiently. This is because nanodiamond materials and filler particles interact better than known solutions and are more uniformly distributed in the polymer matrix. Depending on the choice of the nanodiamond material, its concentration to be added, and the choice of other fillers and the parent polymer, a portion of the added nanodiamond material can also be distributed in the parent polymer as an identifiable material. Therefore, it is possible to finely adjust both the in-plane direction thermal conductivity and the in-plane direction thermal conductivity, and thus the average thermal conductivity.

A PA-66 thermal composite with a total filler loading of 20% by weight, where the nanodiamond material was ball milled with hexagonal boron nitride as a dry powder. The content of nanodiamond in the compound is 1.5% by weight, and the content of hexagonal boron nitride is 18.5% by weight.

The PA-66 thermal composite of the present invention with a total loading of 20 wt% filler, where the nanodiamond material is introduced into the surface of the hexagonal boron nitride in the form of a dispersion, and then the dispersion is The nanodiamond was directly adhered to the surface of the hexagonal boron nitride particles by drying. The content of nanodiamond in the compound is 1.5% by weight, and the content of hexagonal boron nitride is 18.5% by weight.

  In a first aspect of the present invention, a method for producing a composition comprising at least one filler and a nanodiamond material is provided.

  More specifically, as a method for producing a composition comprising at least one filler and a nanodiamond material, (i) a liquid medium containing nanodiamond material is brought into contact with at least one filler to form a suspension. And (ii) removing the liquid medium from the suspension of step (i) to produce a composition comprising at least one filler and a nanodiamond material.

  In step (i), the nanodiamond material-containing liquid medium is contacted with at least one filler to produce a suspension comprising at least one filler, the nanodiamond material and the liquid medium.

  The expression “contacting” as used herein means any known method of contacting a nanodiamond material-containing liquid medium with at least one filler. An example of such a method is mixing the nanodiamond material-containing liquid medium with at least one filler using, for example, a magnetic stirrer. Another example is to spread a nanodiamond material-containing liquid medium on the surface of at least one filler.

  In a preferred embodiment, the nanodiamond material-containing liquid medium is mechanically mixed with at least one filler. This mixing is preferably carried out using a speed mixer.

  The nanodiamond material-containing liquid medium can be contacted with one type of filler or a mixture of two or more types of fillers.

  The average size of the main particles of the filler is preferably 10 nm to 2000 μm, more preferably 50 nm to 500 μm, and further preferably 500 nm to 200 μm.

The size of the filler is generally selected depending on the application and cost.
The form of the filler may be anisotropic or isotropic, or a mixture thereof.

The form of the filler may be regular or irregular.
The surface of the filler may be left as is, or may be activated using various chemical species or treatments.

  The filler can be thermally conductive and / or conductive, or a mixture thereof.

  The choice of filler should be made from the group consisting of metals, metal oxides, metal nitrides, metal carbides, carbon compounds, silicon compounds, boron compounds (eg boron nitride), ceramic materials, natural fibers, and combinations thereof. Is preferred.

  Carbon compounds are selected from diamond materials other than detonated diamond, graphite, carbon black, carbon fiber, graphene, oxidized graphene, soot, carbon nanotube, pyrolytic carbon, silicon carbide, aluminum carbide, carbon nitride, etc. This is done from the group consisting of

  The boron compound is selected from the group consisting of hexagonal boron nitride, cubic boron nitride, boron carbide, and combinations thereof. The boron compound is preferably hexagonal boron nitride.

In one embodiment, the filler is a mixture of boron nitride and aluminum oxide.
In another embodiment, the filler is a mixture of aluminum oxide and graphite. In yet another embodiment, the filler is boron nitride and graphite.

  The nanodiamond material-containing liquid medium of step (i) can be in the form of a dispersion. That is, the nanodiamond material particles are substantially in a single form in the liquid medium.

  The nanodiamond material-containing liquid medium of step (i) can be in the form of a suspension. That is, the nanodiamond material particles are partially in the form of lumps or substantially in the form of lumps in the liquid medium.

  The nanodiamond material-containing liquid medium in step (i) is preferably in the form of a dispersion.

  The nanodiamond material-containing liquid medium can adjust the content of the nanodiamond material.

  The nanodiamond material is a detonated nanodiamond material. That is, nanodiamond is manufactured by the detonation method. In other words, nanodiamonds result from detonation synthesis. Since nanodiamonds are generated by detonation synthesis, the surface of nanodiamond material particles can include several surface functional groups (eg, amino functional groups, carboxylic acid functional groups, hydrogen functional groups).

  The precursor nanodiamond material can be a substantially pure nanodiamond material, preferably having a nanodiamond content of at least 87% by weight, more preferably at least 97% by weight. Nanodiamond materials can include graphite and amorphous carbon derived from the production of nanodiamonds. Nanodiamond materials may also contain some residual metal impurities as metals, metal salts, metal oxides, metal nitrides, metal halides.

  In one embodiment of the invention, the nanodiamond material may contain detonation (eg, graphite and amorphous carbon), and the oxidizable carbon content is preferably at least 5% by weight. More preferably, it is at least 10% by weight.

  The value of the zeta potential of the nanodiamond material preferably exceeds ± 35 mV when dispersed in water.

  When the nanodiamond material is composed of a nanodiamond mixture, it is difficult to reliably determine the zeta potential of the nanodiamond mixture material with currently available instruments.

  In one embodiment, the surface of the nanodiamond material particles is functionalized to increase adhesion of the filler material to the surface. One example of such functionalized nanodiamond material particles is an amino-functionalized nanodiamond material. Another example of such a functionalized nanodiamond is a carboxylic acid functionalized nanodiamond material particle, and yet another example of such a nanodiamond is a hydrogen-terminated nanodiamond material particle. Still other examples of such functionalized nanodiamond material particles include nanodiamond material particles functionalized with hydroxyl, thiol, halogen, ketone, ester, ether, silyl, epoxy, cyano, aldehyde. The surface functional groups are preferably covalently bonded directly to the surface of the nanodiamond material, but can also be present in the chain structure. This chain structure is covalently bonded to the surface of the nanodiamond material particles. The nanodiamond material particles are preferably functionalized mainly with one type of active surface functional group, but may contain two or more types of surface functional groups.

  Adhesion of the filler material to the surface can be adjusted using one or several surface functionalized nanodiamond material particles.

  Furthermore, adhesion to the parent polymer material can be adjusted using one or several surface functionalized nanodiamond material particles.

  The nanodiamond material particles in a single form have an average primary particle size of 1 nm to 10 nm, preferably 2 nm to 8 nm, more preferably 3 nm to 7 nm, and most preferably 4 nm to 6 nm. The size of the particles in the form of lumps is 5 nm to 10000 nm, preferably 60 nm to 800 nm.

  The liquid medium can be any suitable liquid medium. In one embodiment, the liquid medium is selected from the group consisting of polar protic solvents, polar aprotic solvents, dipolar aprotic solvents, organic solvents, and mixtures of these solvents.

  The polar protic solvent is water, alcohol, linear aliphatic diol, branched diol, carboxylic acid.

  The polar aprotic solvent is dichloromethane, tetrahydrofuran, propylene carbonate, lactam.

Dipolar aprotic solvents are ketones, esters, N, N-methylformamide, dimethyl sulfoxide.
The organic solvent is toluene or another aromatic solvent.

  In one preferred embodiment, the choice of liquid medium is water, methanol, ethanol, iso-propanol, linear aliphatic diol, branched diol, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), dimethyl sulfoxide (DMSO), from the group consisting of any mixture of these solvents.

  The most preferred liquid medium is water.

  In one embodiment, the suspension comprising the nanodiamond material, at least one filler and a liquid medium is pretreated prior to step (ii). It is preferred to sonicate the composition to reduce the particle size distribution of the suspension.

  In another embodiment of a suspension comprising nanodiamond material, the composition is mechanically ground to reduce the particle size distribution of the suspension.

  In yet another embodiment of a suspension comprising nanodiamond material, the composition is BASD milled to reduce the particle size distribution of the suspension.

  In step (ii), the liquid medium is removed from the suspension of step (i) to produce a composition comprising at least one filler and a nanodiamond material.

  The removal of the liquid medium can be performed in any suitable manner. Examples of such methods are drying at high temperature and / or drying in vacuum.

  In one preferred embodiment, the composition after removal of the liquid medium is substantially dry.

  In one embodiment of the composition, the nanodiamond material is substantially adhered to the surface of at least one filler, but the liquid medium content is still greater than 10% by weight.

  Using the method of the present invention, the nanodiamond material substantially adheres to the surface of at least one filler.

  The active surface area of the composition produced by the method of the present invention is less than the active surface area of the composition produced by simply mixing the dried nanodiamond material and the filler material. That is, the active surface area of the composition produced by the method of the present invention is less than the active surface area of the composition without nanodiamond material substantially adhered to the surface of at least one filler (which should be at least 5% lower). preferable).

The active surface area is compared between compositions with the same amount of nanodiamond material and filler material. The only difference is how the composition is made. That is, the composition produced by the method of the present invention and the composition produced simply by mixing the dried nanodiamond material and the filler material.
The active surface area can be measured by, for example, the BET method.

  The zeta potential of the composition is different from the zeta potential of the filler material. The zeta potential is driven in the direction of the nanodiamond material included in the composition. Therefore, the zeta potential of the composition is mainly determined by the zeta potential characteristics of the nanodiamond material particles on the surface of the filler particles contained in the composition.

  The surface charge of the composition is different from the surface charge of the filler material. The surface charge is driven in the direction of the nanodiamond material included in the composition. Therefore, the surface charge of the composition is mainly determined by the surface charge characteristics of the nanodiamond material particles on the surface of the filler particles contained in the composition.

  The surface properties of the particles contained in the composition affect the electrostatic interaction of the composition with the parent polymer and facilitate the movement of the phonons, thereby improving the overall thermal conductivity of the formed thermal compound matrix.

  The size of the clumps of adhered nanodiamond material particles is less than 500 nm, preferably less than 300 nm, more preferably less than 100 nm, and most preferably less than 50 nm.

  In one embodiment, the size of the nanodiamond material particle mass may exceed 500 nm.

  In another embodiment of the present invention, the size of the mass of nanodiamond material particles is greater than 500 nm and the nanodiamond material is a nanodiamond mixed material comprising nanodiamond particles.

  In a composition comprising at least one filler and a nanodiamond material, the nanodiamond material on the surface of the filler can generate a coupling effect to another material. The other material is selected from the group consisting of polymers, metals, ceramic materials, and mixtures thereof.

  In one embodiment, the resulting composition comprising at least one filler and a nanodiamond material forms a mass of the composition by further grinding the composition by mechanical processing.

  The mechanical treatment is preferably bead mill grinding. Bead milling is a commonly used term and is known to those skilled in the art.

  A bead mill is a kind of mechanical grinding device, and is a cylindrical device used for grinding (or mixing) various materials. The mill is loaded with the material to be ground and the grinding media. Various materials are used as grinding media. For example, ceramic balls, flint, stainless steel balls and the like can be mentioned. The internal cascade effect reduces the material to a fine powder. The bead mill can be operated continuously or periodically.

  The bead mill apparatus can be operated in a passing or circulating manner. In the pass method, material is fed to one end of the mill and removed from the other end. In the circulation method, the material to be ground is circulated in the system until the required particle size is reached. As the grinding media gets smaller, the particle size of the final product also gets smaller. At the same time, the grinding media particles must be larger than the largest piece of material to be ground.

  The bead mill grinding chamber contains an inert shielding gas (eg nitrogen) that does not react with the material to be ground to prevent any oxidation or explosion reactions that may occur with the air present in the mill. Can also be loaded.

  The beads for the bead mill are selected so that the particles to be ground are of an appropriate diameter. The bead milling is performed until an appropriate particle size is obtained.

  Bead milling may be performed under dry conditions or wet conditions. In wet conditions, the composition is suspended in a liquid medium and the formed suspension is bead milled. Sonication of the suspension can be aided by bead milling. That is, the bead-milling of the suspension and ultrasonic treatment are performed simultaneously. The combination of bead milling and sonication is also known as bead-assisted sonication (BASD). Sonication can be continued throughout the milling or can be stopped at any stage and resumed as needed. After bead milling, the liquid medium is removed in a known manner to produce a bead milled composition.

  In a second aspect of the invention, a method for producing a nanodiamond-containing thermal composite is provided.

  More specifically, the method of producing a nanodiamond-containing thermal composite includes: (i) contacting a nanodiamond material-containing liquid medium with at least one filler to form a suspension; (ii) a liquid Removing the medium from the suspension of step (i) to produce a composition comprising at least one filler and a nanodiamond material; (iii) the composition of step (ii) and at least one polymer. To produce a nanodiamond material-containing thermal composite.

  In step (i), the nanodiamond material-containing liquid medium is contacted with at least one filler to produce a suspension comprising at least one filler, the nanodiamond material and the liquid medium.

  The expression “contacting” means herein any suitable method of contacting a nanodiamond material-containing liquid medium with at least one filler. An example of such a method is mixing the nanodiamond material-containing liquid medium with at least one filler using, for example, a magnetic stirrer. Another example is to spread a nanodiamond material-containing liquid medium on the surface of at least one filler.

  In a preferred embodiment, the nanodiamond material-containing liquid medium is mechanically mixed with at least one filler. This mixing is preferably carried out using a speed mixer.

  The nanodiamond material-containing liquid medium can be contacted with one type of filler or a mixture of two or more types of fillers.

  The average size of the main particles of the filler is preferably 10 nm to 2000 μm, more preferably 50 nm to 500 μm, and further preferably 500 nm to 200 μm.

  The filler can be thermally conductive and / or electrically conductive, or a mixture thereof.

  The choice of filler should be made from the group consisting of metals, metal oxides, metal nitrides, metal carbides, carbon compounds, silicon compounds, boron compounds (eg boron nitride), ceramic materials, natural fibers, and combinations thereof. Is preferred.

  Carbon compounds are selected from diamond materials other than detonated diamond, graphite, carbon black, carbon fiber, graphene, oxidized graphene, soot, carbon nanotube, pyrolytic carbon, silicon carbide, aluminum carbide, carbon nitride, etc. This is done from the group consisting of

  The boron compound is selected from the group consisting of hexagonal boron nitride, cubic boron nitride, boron carbide, and combinations thereof. The boron compound is preferably hexagonal boron nitride.

In one embodiment, the filler is a mixture of boron nitride and aluminum oxide.
In another embodiment, the filler is a mixture of boron nitride, aluminum oxide and graphite.

  The nanodiamond material-containing liquid medium of step (i) can be in the form of a dispersion. That is, the nanodiamond material particles are substantially in a single form in the liquid medium.

  The nanodiamond material-containing liquid medium of step (i) can be in the form of a suspension. That is, the nanodiamond material particles are partially in the form of lumps or substantially in the form of lumps in the liquid medium.

  The nanodiamond material-containing liquid medium in step (i) is preferably in the form of a dispersion.

  The nanodiamond material-containing liquid medium can adjust the content of the nanodiamond material.

  The nanodiamond material is a detonated nanodiamond material. That is, nanodiamond is manufactured by the detonation method. In other words, nanodiamonds result from detonation synthesis. Since nanodiamonds are generated by detonation synthesis, the surface of nanodiamond material particles can include several surface functional groups (eg, amino functional groups, carboxylic acid functional groups, hydrogen functional groups).

  The precursor nanodiamond material can be a substantially pure nanodiamond material, preferably having a nanodiamond content of at least 87% by weight, more preferably at least 97% by weight. Nanodiamond materials can include graphite and amorphous carbon derived from the production of nanodiamonds. Nanodiamond materials may also contain some residual metal impurities as metals, metal salts, metal oxides, metal nitrides, metal halides.

  In one embodiment of the invention, the nanodiamond material may contain detonation (eg, graphite and amorphous carbon), and the oxidizable carbon content is preferably at least 5% by weight, more preferably Is at least 10% by weight.

  The value of the zeta potential of the nanodiamond material preferably exceeds ± 35 mV when dispersed in water.

  When the nanodiamond material is composed of a nanodiamond mixture, it is difficult to reliably determine the zeta potential of the nanodiamond mixture material with currently available instruments.

  In one embodiment, the surface of the nanodiamond material particles is functionalized to increase adhesion of the filler material to the surface. One example of such functionalized nanodiamond material particles is an amino-functionalized nanodiamond material. Another example of such a functionalized nanodiamond is a carboxylic acid functionalized nanodiamond material particle, and yet another example of such a nanodiamond is a hydrogen-terminated nanodiamond material particle. Still other examples of such functionalized nanodiamond material particles include nanodiamond material particles functionalized with hydroxyl, thiol, halogen, ketone, ester, ether, silyl, epoxy, cyano, aldehyde. The surface functional groups are preferably covalently bonded directly to the surface of the nanodiamond material, but can also be present in the chain structure. This chain structure is covalently bonded to the surface of the nanodiamond material particles. The nanodiamond material particles are preferably mainly functionalized with one type of active surface functional group, but may contain two or more types of surface functional groups.

  Adhesion of the filler material to the surface can be adjusted using one or several surface functionalized nanodiamond material particles.

  Furthermore, adhesion to the parent polymer material can be adjusted using one or several surface functionalized nanodiamond material particles.

  The nanodiamond material particles in a single form have an average primary particle size of 1 nm to 10 nm, preferably 2 nm to 8 nm, more preferably 3 nm to 7 nm, and most preferably 4 nm to 6 nm. The size of the particles in the form of lumps is 5 nm to 10000 nm, preferably 60 nm to 800 nm.

  The liquid medium can be any suitable liquid medium. In one embodiment, the liquid medium is selected from the group consisting of polar protic solvents, polar aprotic solvents, dipolar aprotic solvents, organic solvents, and mixtures of these solvents.

  The polar protic solvent is water, alcohol, linear aliphatic diol, branched diol, carboxylic acid.

  The polar aprotic solvent is dichloromethane, tetrahydrofuran, propylene carbonate, lactam.

Dipolar aprotic solvents are ketones, esters, N, N-methylformamide, dimethyl sulfoxide.
The organic solvent is toluene or another aromatic solvent.

In one preferred embodiment, the choice of liquid medium is water, methanol, ethanol, iso-propanol, linear aliphatic diol, branched diol, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), dimethyl sulfoxide (DMSO), from the group consisting of any mixture of these solvents.
The most preferred liquid medium is water.

  In one embodiment, the suspension comprising the nanodiamond material, at least one filler and a liquid medium is pretreated prior to step (ii). It is preferred to sonicate the composition to reduce the particle size distribution of the suspension.

  In another embodiment of a suspension comprising nanodiamond material, the composition is mechanically ground to reduce the particle size distribution of the suspension.

  In yet another embodiment of a suspension comprising nanodiamond material, the composition is BASD milled to reduce the particle size distribution of the suspension.

  In step (ii), the liquid medium is removed from the suspension of step (i) to produce a composition comprising at least one filler and a nanodiamond material.

  The removal of the liquid medium can be performed in any suitable manner. Examples of such methods are drying at high temperature and / or drying in vacuum.

  In one preferred embodiment, the composition after removal of the liquid medium is substantially dry.

  In one embodiment of the composition, the nanodiamond material is substantially adhered to the surface of at least one filler, but the liquid medium content is still greater than 10% by weight.

  The nanodiamond material is substantially adhered to the surface of at least one filler.

  The active surface area of the composition of step (ii) is less than the active surface properties of the composition produced simply by mixing the dry nanodiamond material and the filler material. That is, the active surface area of the composition of step (ii) is smaller (preferably at least 5% smaller) than the active surface area of the composition without the nanodiamond material substantially adhered to the surface of at least one filler.

  The active surface area is compared between compositions with the same amount of nanodiamond material and filler material. The only difference is how the composition is made. That is, the composition produced by the method of the present invention and the composition produced simply by mixing the dried nanodiamond material and the filler material.

  The active surface area can be measured by, for example, the BET method.

  The zeta potential of the composition is different from the zeta potential of the filler material. The zeta potential is driven in the direction of the nanodiamond material included in the composition. Therefore, the zeta potential of the composition is mainly determined by the zeta potential characteristics of the nanodiamond material particles on the surface of the filler particles contained in the composition.

  The surface charge of the composition is different from the surface charge of the filler material. The surface charge is driven in the direction of the nanodiamond material included in the composition. Therefore, the surface charge of the composition is mainly determined by the surface charge characteristics of the nanodiamond material particles on the surface of the filler particles contained in the composition.

  The surface properties of the particles contained in the composition affect the electrostatic interaction of the composition with the parent polymer and facilitate the movement of the phonons, thereby improving the overall thermal conductivity of the formed thermal compound matrix.

  The size of the clumps of adhered nanodiamond material particles is less than 500 nm, preferably less than 300 nm, more preferably less than 100 nm, and most preferably less than 50 nm.

  In one embodiment, the size of the nanodiamond material particle mass may exceed 500 nm.

  In another embodiment of the present invention, the size of the mass of nanodiamond material particles is greater than 500 nm and the nanodiamond material is a nanodiamond mixed material comprising nanodiamond particles.

  In the composition of step (ii) comprising at least one filler and a nanodiamond material, the nanodiamond material on the surface of the filler can generate a coupling effect on another material (eg a polymer).

  In one embodiment, the composition is further ground by mechanical processing to form a mass of the composition. The mechanical treatment is preferably bead mill grinding.

  In step (iii), the composition of step (ii) and at least one filler are mixed to form a nanodiamond-containing thermal composite.

  The polymer is selected from the group consisting of epoxy, silicone, thermoplastic polymer, acrylate, polyurethane, polyester, fluoropolymer, siloxane, polyimide, and mixtures thereof.

  In one preferred embodiment, the polymer is a thermoplastic polymer or a mixture of thermoplastic polymers. Examples of thermoplastic polymers are acrylonitrile butadiene styrene, acrylic resin, celluloid, cellulose acetate, cyclic olefin copolymer, ethylene-vinyl acetate, ethylene vinyl alcohol, fluoroplastic (eg polytetrafluoroethylene), ionomer, liquid crystal polymer, polyoxy Methylene, polyacrylate, polyacrylonitrile, polyamide, polyamide-imide, polyimide, polyaryletherketone, polybutadiene, polybutylene, butylene polyterephthalate, polycaprolactone, polychlorotrifluoroethylene, polyetheretherketone, polyethylene terephthalate, poly Cyclohexylene dimethylene terephthalate, polycarbonate, polyhydroxyalkanoate, polyketone, polyester , Polyethylene, polyetherketoneketone, polyetherimide, polyethersulfone, polysulfone, chlorinated polyethylene, polyacetic acid, polymethyl methacrylate, polymethylpentene, polyphenylene, polyphenylene oxide, polyphenylene sulfide, polyphthalamide, polypropylene, polystyrene, Polysulfone, trimethylene polyterephthalate, polyurethane, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, and styrene-acrylonitrile.

  Preferred thermoplastic polymers are acrylonitrile butadiene styrene, polyphenylene sulfide, liquid crystal polymer, polypropylene, polyethylene, polystyrene, polysulfone, polyetherimide, trimethylene polyterephthalate, polycarbonate, polyamide, polyphthalamide, polyetheretherketone, or It is a mixture of these.

  In another preferred embodiment, the polymer is silicone. Silicones can be obtained in the form of pure polymer slurries or dispersed in a solvent.

  In yet another preferred embodiment, the polymer is an epoxy. The epoxy can be obtained in the form of a pure polymer slurry or dispersed in a solvent.

  Mixing can be performed in any manner that contacts the composition of step (ii) with at least one polymer. Examples of such methods are mechanical mixing, mechanical high temperature mixing, extrusion.

  In one embodiment, the composition of step (ii) and at least one polymer are mixed in an extruder at an elevated temperature.

  In yet another embodiment, the composition of step (ii) and at least one polymer are mixed and molded at an elevated temperature to produce a nanodiamond-containing thermal composite. Molding can be performed by any known method. For example, there are injection molding, compression molding, and rotational molding. The molding is preferably injection molding. In a preferred embodiment, mixing and molding are performed in a single device (eg, an injection molding device).

  In one embodiment, the polymer form is formed from the monomers. The nanodiamond-containing thermal composite is formed by curing the monomer contained in the monomer mixture and the nanodiamond-containing composition.

  In one embodiment, the polymer form is formed from monomers dispersed in a solvent. The nanodiamond-containing thermal composite is formed by curing the monomer contained in the monomer mixture, the solvent, and the nanodiamond-containing composition.

  The nanodiamond-containing composition can be added as a powder or in the form of a dispersion / suspension, to the liquid phase polymer, to the monomer, or to a mixture thereof.

  Optionally, additional components can be added in step (iii). An example of such a component is a surfactant (eg titanate).

  Nanodiamond-containing thermal composites can take a variety of forms (eg, products, pellets, powders).

  The resulting nanodiamond-containing thermal composite includes a nanodiamond material, at least one filler, and at least one polymer, wherein the nanodiamond material is substantially on the surface of the at least one filler. Glued.

  The average thermal conductivity of the composite is at least 5% greater than the average thermal conductivity of a nanodiamond-containing composite in which the nanodiamond material is not substantially adhered to the surface of at least one filler.

  The thermal conductivity of the composite is preferably at least 20% greater than the average thermal conductivity of the nanodiamond-containing composite in which the nanodiamond material is not substantially adhered to the surface of the at least one filler, % Larger is more preferable, and 70% larger is more preferable.

  The thermal conductivity is compared between a composite comprising nanodiamond material, filler material and polymer containing the same amount of composition. The only difference is how the composition is made. That is, the composition produced by the method of the present invention and the composition produced simply by mixing the dry nanodiamond material and the filler material and then the polymer material.

  In a third aspect of the invention, a composition comprising a nanodiamond material and at least one filler is provided.

  More particularly, it comprises 0.01 to 80% by weight of nanodiamond material and 1 to 99.99% by weight of at least one filler, the nanodiamond material being substantially on the surface of the at least one filler. Adhering compositions are provided.

  The composition preferably contains 0.01 to 40% by weight of nanodiamond material, more preferably 0.01 to 20% by weight, and most preferably 0.01 to 5% by weight.

  The composition preferably contains 10 to 90% by weight of at least one filler, more preferably 20 to 99.99% by weight, even more preferably 15 to 85% by weight, and 15 to 70% by weight. Is more preferable, and it is most preferable to contain 20 to 50% by weight.

  In one embodiment, the composition comprises 0.01-5% by weight nanodiamond material and 95-99.99% by weight of at least one filler.

  The active surface area of the composition is less than the active surface area of the composition in which the nanodiamond material is not substantially adhered to the surface of at least one filler (preferably at least 5% less).

  The active surface area is compared between compositions with the same amount of nanodiamond material and filler material. That is, the only difference is that in the composition of the present invention, the nanodiamond material is substantially adhered to the surface of the filler material, whereas the comparative composition has no adhesion.

  The active surface area can be measured by, for example, the BET method.

  The zeta potential of the composition is different from the zeta potential of the filler material. The zeta potential is driven in the direction of the nanodiamond material included in the composition. Therefore, the zeta potential of the composition is mainly determined by the zeta potential characteristics of the nanodiamond material particles on the surface of the filler particles contained in the composition.

  The surface charge of the composition is different from the surface charge of the filler material. The surface charge is driven in the direction of the nanodiamond material included in the composition. Therefore, the surface charge of the composition is mainly determined by the surface charge characteristics of the nanodiamond material particles on the surface of the filler particles contained in the composition.

  The surface properties of the particles contained in the composition affect the electrostatic interaction of the composition with the parent polymer and facilitate the movement of the phonons, thereby improving the overall thermal conductivity of the formed thermal compound matrix.

  The choice of filler should be made from the group consisting of metals, metal oxides, metal nitrides, metal carbides, carbon compounds, silicon compounds, boron compounds (eg boron nitride), ceramic materials, natural fibers, and combinations thereof. Is preferred.

  Carbon compounds are selected from diamond materials other than detonated diamond, graphite, carbon black, carbon fiber, graphene, oxidized graphene, soot, carbon nanotubes, pyrolytic carbon, carbon nitride, silicon carbide, aluminum carbide, etc. This is done from the group consisting of

  The boron compound is selected from the group consisting of hexagonal boron nitride, cubic boron nitride, boron carbide, and combinations thereof. The boron compound is preferably hexagonal boron nitride.

  In one embodiment, the filler is a mixture of boron nitride and aluminum oxide.

  In another embodiment, the filler is a mixture of boron nitride, aluminum oxide and graphite.

  The average size of the main particles of the filler is 10 nm to 2000 μm, more preferably 50 nm to 500 μm, and still more preferably 500 nm to 200 μm.

  The nanodiamond material is a detonated nanodiamond material. That is, nanodiamond is manufactured by the detonation method. In other words, nanodiamonds result from detonation synthesis. Since nanodiamonds are generated by detonation synthesis, the surface of nanodiamond material particles can include several surface functional groups (eg, amino functional groups, carboxylic acid functional groups, hydrogen functional groups).

  The precursor nanodiamond material can be a substantially pure nanodiamond material, preferably having a nanodiamond content of at least 87% by weight, more preferably at least 97% by weight. Nanodiamond materials can include graphite and amorphous carbon derived from the production of nanodiamonds. Nanodiamond materials may also contain some residual metal impurities in the form of metals, metal salts, metal oxides.

  In one embodiment of the invention, the nanodiamond particles may contain detonation (eg graphite and amorphous carbon), and the oxidizable carbon content is preferably at least 5% by weight, more preferably Is at least 10% by weight.

  The value of the zeta potential of the nanodiamond material preferably exceeds ± 35 mV when dispersed in water.

  When the nanodiamond material is composed of a nanodiamond mixture, it is difficult to reliably determine the zeta potential of the nanodiamond mixture material with currently available instruments.

  The nanodiamond material particles in a single form have an average primary particle size of 1 nm to 10 nm, preferably 2 nm to 8 nm, more preferably 3 nm to 7 nm, and most preferably 4 nm to 6 nm. The size of the particles in the form of lumps is 5 nm to 1000 nm, preferably 60 nm to 800 nm.

  In one embodiment, the surface of the nanodiamond material particles is monofunctionalized to increase the adhesion of the filler material to the surface. An example of such monofunctionalized nanodiamond material particles is an amino functionalized nanodiamond material.

  The size of the clumps of adhered nanodiamond material particles is less than 500 nm, preferably less than 300 nm, more preferably less than 100 nm, and most preferably less than 50 nm.

  The nanodiamond material on the surface of the filler can generate a coupling effect to another material. The other material is selected from the group consisting of polymers, metals, ceramic materials, and mixtures thereof.

  In one embodiment, a composition of the present invention comprising a nanodiamond material and at least one filler can be obtained by the method disclosed above.

  In a fourth aspect of the invention, a nanodiamond-containing thermal composite comprising nanodiamond particles, at least one filler, and at least one polymer is provided.

  More particularly, the nanodiamond material comprises 0.01 to 80% by weight of nanodiamond material, 1 to 90% by weight of at least one filler, and 5 to 95% by weight of at least one polymer. A nanodiamond-containing thermal composite is provided that is substantially adhered to the surface of the at least one filler.

  Preference is given to the composite comprising 0.01 to 40% by weight of nanodiamond material, preferably 0.01 to 20% by weight, more preferably 0.01 to 5% by weight.

  Preference is given to the composite comprising 10 to 70% by weight, preferably 10 to 50% by weight, more preferably 15 to 45% by weight, of at least one filler.

  Preference is given to the composite comprising 20 to 90% by weight, preferably 50 to 85% by weight, of at least one polymer.

  The average thermal conductivity of the composite is at least 5% greater than the average thermal conductivity of the composite in which the nanodiamond material is not substantially adhered to the surface of at least one filler.

  Preferably, the average thermal conductivity of the composite is at least 20% greater than the average thermal conductivity of the composite with substantially no nanodiamond material adhered to the surface of at least one filler, preferably It is 50% larger, more preferably 70% larger.

  The average thermal conductivity is compared between composites comprising nanodiamond material, filler material and polymer containing the same amount of composition. The only difference is how the composition is made. That is, in the composite of the present invention, the nanodiamond material is substantially adhered to the surface of at least one filler material, whereas the comparative composition is not.

  The polymer is selected from the group consisting of epoxy, silicone, thermoplastic polymer, acrylate, polyurethane, polyester, fluoropolymer, siloxane, polyimide, and mixtures thereof.

  In one preferred embodiment, the polymer is a thermoplastic polymer or a mixture of thermoplastic polymers. Examples of thermoplastic polymers are acrylonitrile butadiene styrene, acrylic resin, celluloid, cellulose acetate, cyclic olefin copolymer, ethylene-vinyl acetate, ethylene vinyl alcohol, fluoroplastic (eg polytetrafluoroethylene), ionomer, liquid crystal polymer, polyoxy Methylene, polyacrylate, polyacrylonitrile, polyamide, polyamide-imide, polyimide, polyaryletherketone, polybutadiene, polybutylene, butylene polyterephthalate, polycaprolactone, polychlorotrifluoroethylene, polyetheretherketone, polyethylene terephthalate, poly Cyclohexylene dimethylene terephthalate, polycarbonate, polyhydroxyalkanoate, polyketone, polyester , Polyethylene, polyetherketoneketone, polyetherimide, polyethersulfone, polysulfone, chlorinated polyethylene, polyacetic acid, polymethyl methacrylate, polymethylpentene, polyphenylene, polyphenylene oxide, polyphenylene sulfide, polyphthalamide, polypropylene, polystyrene, Polysulfone, trimethylene polyterephthalate, polyurethane, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, and styrene-acrylonitrile.

  Preferred thermoplastic polymers are acrylonitrile butadiene styrene, polyphenylene sulfide, liquid crystal polymer, polypropylene, polyethylene, polystyrene, polysulfone, polyetherimide, trimethylene polyterephthalate, polycarbonate, polyamide, polyphthalamide, polyetheretherketone, or It is a mixture of these.

  In another preferred embodiment, the polymer is silicone. Silicones can be obtained in the form of pure polymer slurries or dispersed in a solvent.

  In yet another preferred embodiment, the polymer is an epoxy. The epoxy can be obtained in the form of a pure polymer slurry or dispersed in a solvent.

  In one embodiment, the polymer form is formed from monomers. The nanodiamond-containing thermal composite is formed by curing the monomer contained in the monomer mixture and the nanodiamond-containing composition.

  In one embodiment, the polymer form is formed from monomers dispersed in a solvent. The nanodiamond-containing thermal composite is formed by curing the monomer contained in the monomer mixture, the solvent, and the nanodiamond-containing composition.

  The nanodiamond-containing composition can be added as a powder or in the form of a dispersion / suspension, to the liquid phase polymer, to the monomer, or to a mixture thereof.

  The choice of filler should be made from the group consisting of metals, metal oxides, metal nitrides, metal carbides, carbon compounds, silicon compounds, boron compounds (eg boron nitride), ceramic materials, natural fibers, and combinations thereof. Is preferred.

  Carbon compounds are selected from diamond materials other than detonated diamond, graphite, carbon black, carbon fiber, graphene, oxidized graphene, soot, carbon nanotubes, pyrolytic carbon, carbon nitride, silicon carbide, aluminum carbide, etc. This is done from the group consisting of

  The boron compound is selected from the group consisting of hexagonal boron nitride, cubic boron nitride, boron carbide, and combinations thereof. The boron compound is preferably hexagonal boron nitride.

  In one embodiment, the filler is a mixture of boron nitride, aluminum oxide and graphite.

  The average size of the main particles of the filler is 10 nm to 100 μm, more preferably 50 nm to 50 μm, and still more preferably 500 nm to 20 μm.

  The nanodiamond material is a detonated nanodiamond material. That is, nanodiamond is manufactured by the detonation method. In other words, nanodiamonds result from detonation synthesis. Since nanodiamonds are generated by detonation synthesis, the surface of nanodiamond material particles can include several surface functional groups (eg, amino functional groups, carboxylic acid functional groups, hydrogen functional groups).

  The precursor nanodiamond material can be a substantially pure nanodiamond material, preferably having a nanodiamond content of at least 87% by weight, more preferably at least 97% by weight. Nanodiamond materials can include graphite and amorphous carbon derived from the production of nanodiamonds. Nanodiamond materials may also contain some residual metal impurities as metals, metal salts, metal oxides, metal nitrides, metal halides.

  In one embodiment of the invention, the nanodiamond material may contain detonation (eg, graphite and amorphous carbon), and the oxidizable carbon content is preferably at least 5% by weight, more preferably Is at least 10% by weight.

  The value of the zeta potential of the nanodiamond material preferably exceeds ± 35 mV when dispersed in water.

  When the nanodiamond material is composed of a nanodiamond mixture, it is difficult to reliably determine the zeta potential of the nanodiamond mixture material with currently available instruments.

  The nanodiamond material particles in a single form have an average primary particle size of 1 nm to 10 nm, preferably 2 nm to 8 nm, more preferably 3 nm to 7 nm, and most preferably 4 nm to 6 nm. The size of the particles in the form of lumps is 5 nm to 1000 nm, preferably 60 nm to 800 nm.

  In one embodiment, the surface of the nanodiamond material particles is functionalized to increase adhesion of the filler material to the surface. One example of such functionalized nanodiamond material particles is an amino-functionalized nanodiamond material. Another example of such a functionalized nanodiamond is a carboxylic acid functionalized nanodiamond material particle, and yet another example of such a nanodiamond is a hydrogen-terminated nanodiamond material particle. Still other examples of such functionalized nanodiamond material particles include nanodiamond material particles functionalized with hydroxyl, thiol, halogen, ketone, ester, ether, silyl, epoxy, cyano, aldehyde. The surface functional groups are preferably covalently bonded directly to the surface of the nanodiamond material, but can also be present in the chain structure. This chain structure is covalently bonded to the surface of the nanodiamond material particles. The nanodiamond material particles are preferably mainly functionalized with one type of active surface functional group, but may contain two or more types of surface functional groups.

  Adhesion of the filler material to the surface can be adjusted using one or several surface functionalized nanodiamond material particles.

  Furthermore, adhesion to the parent polymer material can be adjusted using one or several surface functionalized nanodiamond material particles.

  The size of the clumps of adhered nanodiamond material particles is less than 500 nm, preferably less than 300 nm, more preferably less than 100 nm, and most preferably less than 50 nm.

  In one embodiment, the size of the nanodiamond material particle mass may exceed 500 nm.

  In another embodiment of the present invention, the size of the mass of nanodiamond material particles is greater than 500 nm and the nanodiamond material is a nanodiamond mixed material comprising nanodiamond particles.

  The nanodiamond material on the surface of the filler can generate a coupling effect on at least one polymer.

  Nanodiamond-containing thermal composites can be in various forms (eg, products, pellets, powders).

  In one embodiment of the invention, the nanodiamond-containing thermal composite can be obtained in the form of a solvent, the nanodiamond-containing thermal composite being dispersed or suspended in a suitable solvent. Curing such solvent forms, including nanodiamond thermal composites, forms solid or substantially solid nanodiamond-containing thermal composites in the form of films, coatings, particles, products, pellets, powders be able to.

  In another embodiment of the invention, a nanodiamond-containing composition is added to silicone to form a nanodiamond-containing thermal composite. The silicone-containing thermal composite can be cured by heat and / or by light irradiation (eg, UV light) and / or by use of a catalyst. One particularly preferred catalyst is platinum.

  In another embodiment of the invention, the nanodiamond-containing composition is added to the epoxide to form a nanodiamond-containing thermal composite. The epoxide-containing thermal composite can be cured by heat and / or by irradiation and / or by use of a curing agent. One particularly preferred curing agent is an amine curing agent.

  In one embodiment, the nanodiamond-containing thermal composite exhibits a Young's modulus greater than a thermal composite that uses the same filler as the nanodiamond-containing thermal composite and has the same weight percent loading.

  In one embodiment, the nanodiamond-containing thermal composite exhibits greater scratch resistance than a thermal composite that uses the same filler as the nanodiamond-containing thermal composite and has the same weight percent loading.

  In one embodiment, the nanodiamond-containing thermal composite exhibits a smaller coefficient of friction than a thermal composite that uses the same filler as the nanodiamond-containing thermal composite and has the same weight percent loading.

  In one embodiment, the nanodiamond-containing thermal composite of the present invention comprising a nanodiamond material, at least one filler and at least one polymer can be obtained by the method disclosed above.

  Hereinafter, the present invention will be described in more detail by way of examples. The purpose of the examples is not to limit the scope of the claims.

Example 1 (according to the invention)
This example demonstrates the preparation of a thermally conductive and electrically insulating PA-66 composition.

Material Polyamide-66 (PA-66):
The PA-66 used in the test was PA-66 grade Zytel 135F (powder PA-66). This is commercially available.

Boron nitride:
The boron nitride used in this example was a 15 micron hexagonal boron nitride powder Boronid® TCP015-100 available from ESK Ceramics GmbH.

Zeta positive amino functionalized nanodiamond dispersion in water:
The zeta positive amino functionalized nanodiamond dispersion is an amino functionalized nanodiamond dispersion developed by Carbodeon with a nanodiamond content of 5% by weight. The crystal size of nanodiamond is 4-6 nm. The content of nanodiamond in the solid phase is 97% by weight or more. The nanodiamond particles of the amino-functionalized nanodiamond dispersion are detonated nanodiamonds, whose base value measured by titration is at least 10.0 and its acid value is less than 3.0. The pH of this aqueous dispersion is a minimum of 8.0 when measured at a content of 5% by weight. The zeta potential of this amino-functionalized nanodiamond dispersion is at least +35 mV when measured with a dispersion without pH modifier. This grade of D90 particle size distribution is less than 30 nm. The content of the aqueous amino functionalized nanodiamond grade used was 5% by weight.

Underwater Vox D
The product named “Vox D” (from Carbodeon) contains a dispersion of spherical nanodiamond particles, mainly having carboxylic acid functionalized nanodiamonds on the surface, in water and various other solvents. The crystal size of nanodiamond is 4-6 nm. The content of nanodiamond in the solid phase is 97% by weight or more. “Vox D” is commercially available. “Vox D” nanodiamond particles are detonated nanodiamonds. The typical value of the zeta potential of this commercially available dispersion is at least -50 mV and the D90 particle size distribution is less than 30 nm, preferably less than 15 nm. The content of aqueous Vox D grade nanodiamond used was 5% by weight.

Underwater hydrogen D
A product named “Hydrogen D” (from Carbodeon) contains a dispersion of spherical nanodiamond particles, mainly having hydrogen-functionalized nanodiamonds on the surface, in water and various other solvents. The crystal size of nanodiamond is 4-6 nm. The content of nanodiamond in the solid phase is 97% by weight or more. “Vox D” is commercially available. “Vox D” nanodiamond particles are detonated nanodiamonds. Typical values for the zeta potential of this commercially available dispersion are at least +40 mV when measured with an aqueous dispersion without a pH modifier and the D90 particle size distribution is less than 30 nm, preferably less than 15 nm. “Hydrogen D” nanodiamond particles are detonated nanodiamonds. The content of the aqueous dispersion used was 3.5% by weight.

Preparation of composition from nanodiamond dispersion and boron nitride filler:
Amino-2:
24.722g boron nitride and 5.5ml zeta positive amino functionalized nanodiamond dispersion (0.5wt% aqueous dispersion containing 0.0275g solids) are mixed together and a speed mixer device (Speed Mixer DAC 150.1 FV ) For 1 minute. This amino-functionalized nanodiamond dispersion with positive zeta spread evenly throughout the boron nitride matrix. The resulting mixture was dried overnight in an oven (80 ° C.) and the dried material was retzch 100 PM100 ball mill grinding tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide container) Was then used to obtain a composition in which the nanodiamond mixed material adhered well to the surface of the graphite particles. Using a portion of the composition thus prepared, a PA-66 compound containing 0.05 wt% zeta positive amino functionalized nanodiamond and 44.95 wt% hexagonal boron nitride material was prepared (Sample 4). ).

  24.695 g boron nitride and 11.0 ml zeta positive amino-functionalized nanodiamond dispersion (0.5 wt% aqueous dispersion containing 0.055 g solids) are mixed together and a speed mixer device (Speed Mixer DAC 150.1 FV ) For 1 minute. This amino-functionalized nanodiamond dispersion with positive zeta spread evenly throughout the boron nitride matrix. The resulting mixture was dried overnight in an oven (80 ° C.) and the dried material was retzch 100 PM100 ball mill grinding tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide container) Was then used to obtain a composition in which the nanodiamond mixed material adhered well to the surface of the graphite particles. Using a portion of the composition thus prepared, a PA-66 compound containing 0.1 wt% zeta-positive amino-functionalized nanodiamond and 44.9 wt% hexagonal boron nitride material was prepared (Sample 5). ).

  48.95 g boron nitride and 55.0 ml zeta positive amino-functionalized nanodiamond dispersion (1.0 wt% aqueous dispersion containing 0.55 g solid) are mixed together and a speed mixer device (Speed Mixer DAC 150.1 FV ) For 1 minute. This amino-functionalized nanodiamond dispersion with positive zeta spread evenly throughout the boron nitride matrix. The resulting mixture was dried overnight in an oven (80 ° C.) and the dried material was retzch 100 PM100 ball mill grinding tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide container) Was then used to obtain a composition in which the nanodiamond mixed material adhered well to the surface of the graphite particles. Using a portion of the composition thus prepared, a PA-66 compound containing 0.5 wt% zeta-positive amino-functionalized nanodiamond and 44.5 wt% hexagonal boron nitride material was prepared (Sample 6). ).

  64.35 g boron nitride and 33.0 ml zeta positive amino-functionalized nanodiamond dispersion (5.0 wt% aqueous dispersion containing 1.65 g solid) are mixed together and a speed mixer device (Speed Mixer DAC 150.1 FV ) For 1 minute. This amino-functionalized nanodiamond dispersion with positive zeta spread evenly throughout the boron nitride matrix. The resulting mixture was dried overnight in an oven (80 ° C.) and the dried material was retzch 100 PM100 ball mill grinding tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide container) Was then used to obtain a composition in which the nanodiamond mixed material adhered well to the surface of the graphite particles. Using a portion of the composition thus prepared, a PA-66 compound containing 0.5 wt% zeta positive amino functionalized nanodiamond and 19.5 wt% hexagonal boron nitride material was prepared (Sample 7). ).

Vox-2:
24.722g boron nitride and 5.5ml Vox-D nanodiamond dispersion (0.5wt% aqueous dispersion containing 0.0275g solids) are mixed together and using a speed mixer device (Speed Mixer DAC 150.1 FV) Treated for 1 minute. This carboxylic acid functionalized nanodiamond dispersion with negative zeta spread evenly throughout the boron nitride matrix. The resulting mixture was dried overnight in an oven (80 ° C.) and the dried material was retzch 100 PM100 ball mill grinding tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide container) Was then used to obtain a composition in which the nanodiamond mixed material adhered well to the surface of the graphite particles. A portion of the composition thus prepared was used to prepare a PA-66 compound containing 0.05 wt% zeta negative carboxylic acid functionalized nanodiamond and 44.95 wt% hexagonal boron nitride material (sample) 8).

  24.695 g boron nitride and 11.0 ml zeta negative carboxylic acid functionalized nanodiamond dispersion Vox-D (0.5 wt% aqueous dispersion containing 0.055 g solid) are mixed together and a speed mixer device (Speed Mixer DAC 150.1 FV) was used for 1 minute. This carboxylic acid functionalized nanodiamond dispersion with negative zeta spread evenly throughout the boron nitride matrix. The resulting mixture was dried overnight in an oven (80 ° C.) and the dried material was retzch 100 PM100 ball mill grinding tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide container) Was then used to obtain a composition in which the nanodiamond mixed material adhered well to the surface of the graphite particles. Using a portion of the composition thus prepared, a PA-66 compound containing 0.1 wt% zeta negative carboxylic acid functionalized nanodiamond and 44.9 wt% hexagonal boron nitride material was prepared (sample 9).

  47.85 g boron nitride and 33.0 ml zeta negative carboxylic acid functionalized nanodiamond dispersion Vox D (5.0 wt% aqueous dispersion containing 1.65 g solids) are mixed together and a speed mixer device (Speed Mixer DAC 150.1 FV) for 1 minute. This carboxylic acid functionalized nanodiamond dispersion with negative zeta spread evenly throughout the boron nitride matrix. The resulting mixture was dried overnight in an oven (80 ° C.) and the dried material was retzch 100 PM100 ball mill grinding tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide container) Was then used to obtain a composition in which the nanodiamond mixed material adhered well to the surface of the graphite particles. A portion of the composition thus prepared was used to prepare a PA-66 compound containing 1.5 wt% zeta negative carboxylic acid functionalized nanodiamond and 43.5 wt% hexagonal boron nitride material (sample) Ten).

  61.05 g boron nitride and 99.0 ml zeta negative carboxylic acid functionalized nanodiamond dispersion Vox D (5.0 wt% aqueous dispersion containing 4.95 g solid) are mixed together and a Speed Mixer DAC 150.1 FV) for 1 minute. This carboxylic acid functionalized nanodiamond dispersion with negative zeta spread evenly throughout the boron nitride matrix. The resulting mixture was dried overnight in an oven (80 ° C.) and the dried material was retzch 100 PM100 ball mill grinding tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide container) Was then used to obtain a composition in which the nanodiamond mixed material adhered well to the surface of the graphite particles. A portion of the composition thus prepared was used to prepare a PA-66 compound containing 1.5 wt% zeta negative carboxylic acid functionalized nanodiamond and 18.5 wt% hexagonal boron nitride material (sample) 11).

Hydrogen-2:
21.89 g of boron nitride and 22.0 ml of zeta positive hydrogen functionalized nanodiamond dispersion hydrogen D (0.5 wt% aqueous dispersion containing 0.11 g of solid) are mixed together and a speed mixer device (Speed Mixer DAC 150.1 FV) for 1 minute. This hydrogen-functionalized nanodiamond dispersion hydrogen D with positive zeta spread evenly throughout the boron nitride matrix. The resulting mixture was dried overnight in an oven (80 ° C.) and the dried material was retzch 100 PM100 ball mill grinding tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide container) Was then used to obtain a composition in which the nanodiamond mixed material adhered well to the surface of the graphite particles. A portion of the composition thus prepared was used to prepare a PA-66 compound containing 0.1 wt% zeta positive hydrogen functionalized nanodiamond and 19.9 wt% hexagonal boron nitride material (Sample 12). ).

  24.695 g boron nitride and 11.0 ml zeta positive hydrogen functionalized nanodiamond dispersion hydrogen D (0.5 wt% aqueous dispersion containing 0.055 g solid) are mixed together and a speed mixer device (Speed Mixer DAC 150.1 FV) for 1 minute. This hydrogen-functionalized nanodiamond dispersion hydrogen D with positive zeta spread evenly throughout the boron nitride matrix. The resulting mixture was dried overnight in an oven (80 ° C.) and the dried material was retzch 100 PM100 ball mill grinding tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide container) Was then used to obtain a composition in which the nanodiamond mixed material adhered well to the surface of the graphite particles. Using a portion of the composition thus prepared, a PA-66 compound containing 0.1 wt% zeta positive hydrogen functionalized nanodiamond and 49.9 wt% hexagonal boron nitride material was prepared (Sample 13). ).

Treatment All materials were dried and then mixed (PA-66: 2 hours in a dry air dryer / 120 ° C).
Mixing was performed using an Xplore 15 microcompound and test specimens were injection molded using a Thermo-Haake Minijet. A special mold (25 x 25 x 3mm) for Minijet was used. After producing three similar composites for each series, the thermal conductivity and density were analyzed.

  Sample 1: PA-66 thermoplastic polymer was placed in a compound. The mixing and molding temperature was 290 ° C. The screw rotation speed during mixing was 100 rpm and the mixing time was at least 5 minutes. The mold temperature was 70 ° C. With the Minijet, the loading time at 800 bar was 5 seconds and the cooling time at 500 bar was 15 seconds. The total weight of the samples was 11 grams each. Sample 1 is a reference sample containing no filler.

  Samples 2-3: Boron nitride powder and PA-66 thermoplastic polymer were placed in a compound. The mixing and molding temperature was 290 ° C. The screw rotation speed during mixing was 100 rpm and the mixing time was at least 5 minutes. The mold temperature was 70 ° C. With the Minijet, the loading time at 800 bar was 5 seconds and the cooling time at 500 bar was 15 seconds. The total weight of the samples was 11 grams each and the total loading of the filler was 20 wt% (Sample 2) or 45 wt% (Sample 3). Samples 2 and 3 are representative reference samples containing only boron nitride filler.

  Samples 4-14: A composition comprising PA-66 thermoplastic polymer and nanodiamond dried on the surface of boron nitride particles was placed in a compound. The mixing and molding temperature was 290 ° C. The screw rotation speed during mixing was 100 rpm and the mixing time was at least 5 minutes. The mold temperature was 70 ° C. With the Minijet, the loading time at 800 bar was 5 seconds and the cooling time at 500 bar was 15 seconds. The total weight of the samples was 11 grams each and the total loading of the filler was 20% or 45% by weight. When the total loading of the prepared sample filler is 20% by weight, the loading of boron nitride filler is varied between 18.5 and 19.95% by weight and the nanodiamond content is between 0.05 and 1.5% by weight It was changed with. When the total loading of the prepared sample filler is 45 wt%, the boron nitride filler loading is varied between 44.5 and 44.95 wt% and the nanodiamond content is between 0.05 and 0.5 wt% It was changed with.

Analysis The thermal conductivity (λ) of the manufactured PA-66 thermal compound sample was determined by the laser flash method (ISO 18755; LFA 447, Netzsch GmbH) at ESK Ceramics GmbH, and Pyroseram was used as the reference material (5 times). And average). The measured value is the thermal diffusivity a. This value is measured in three directions of space, that is, the x direction, the y direction, and the z direction (plane penetration direction = z sample, in-plane direction parallel to the molding direction = y sample, in-plane direction perpendicular to the molding direction = x samples). The measurement was performed at room temperature (25 ° C.). The density (ρ) of the sample was measured by the Archimedes method. calculated specific heat C _P using the measurement results for z samples. The thermal conductivity was calculated according to λ = a × C _P × ρ using the density ρ, C _P , and a.

Results The results are summarized in Table 1. Error of the density measurement is ± 0.002g / cm ^3, the error of the thermal diffusivity measuring is ± 5%, the error of the calculated C _P is 15% or less. Since the specific heat value of each sample is the same in the x, y, and z directions, only one value is shown for each sample.

  After grinding nanodiamond filler with boron nitride filler by ball milling, the resulting filler mixture is incorporated into the thermoplastic polymer itself, compared to the method of adding multiple fillers to the thermoplastic matrix separately. It has been shown previously that thermal conductivity is improved. Compared to a reference sample containing 45.0 wt% boron nitride filler (Sample 3), the composition containing 44.95 wt% boron nitride filler and 0.05 wt% amino-2 has an in-plane thermal conductivity of 21.9 %, The average thermal conductivity is improved by 14.0% (Sample 4). Thus, a significant improvement in thermal conductivity is already obtained with compounds with a very low content of nanodiamond material.

  Compared to a reference sample containing 45.0 wt% boron nitride filler (Sample 3), the use of a composition containing 44.9 wt% boron nitride filler and 0.1 wt% amino-2 results in in-plane thermal conductivity Is improved by 42.3% and the average thermal conductivity by 31.1% (Sample 5). This result has been reproduced by preparing another similar sample, improving the in-plane thermal conductivity by 39.8% and the average thermal conductivity by 34.1% (X: 4.58; Y: 5.26; Z: 1.96). Similar compounds were prepared by mixing boron nitride filler with amino functionalized nanodiamond Molto Nuevo (which has a lower proportion of amino functional groups compared to the amino functionalized nanodiamond material used in this example) as a dry powder on a machine. When mixing the resulting compositions, the corresponding improvements are in-plane thermal conductivity of 25.0% and average thermal conductivity of 24.9%.

  In addition, the use of a composition containing 44.5 wt% boron nitride filler and 0.5 wt% amino-2 (sample 6) compared to a reference sample containing 45.0 wt% boron nitride filler (sample 3) The in-plane thermal conductivity increases by 16.8% and the average thermal conductivity increases by 17.4%. When mixing the same content of boron nitride and zeta-positive amino-functionalized nanodiamond powder (precursor for producing a positive-functional aminofunctional nanodiamond dispersion of zeta) after pulverizing each other as dry powder In-plane thermal conductivity is improved by 12.8% and average thermal conductivity is improved by 11.9%.

  In addition, a composition comprising 19.5 wt% boron nitride material and 0.5 wt% amino functionalized nanodiamond (amino-2) is in-plane compared to a reference sample containing 20 wt% boron nitride in a PA-66 matrix. The directional thermal conductivity is improved by 10.6% and the average thermal conductivity is improved by 11.8% (Sample 7).

  Compared to a reference sample containing 45.0 wt% boron nitride filler (Sample 3), the use of a composition containing 44.95 wt% boron nitride filler and 0.05 wt% carboxylated nanodiamond particles (Vox-2) The in-plane thermal conductivity is improved by 36.3% and the average thermal conductivity is improved by 29.4% (Sample 8). Thus, a significant improvement in thermal conductivity is already obtained with compounds with a very low content of nanodiamond material.

  When making a composite using a composition of Vox-2 containing 44.9 wt% boron nitride filler and 0.1 wt% carboxylated nanodiamond particles, 45.0 wt% boron nitride filler is added to the PA-66 compound. Compared with the included reference sample (sample 3), the in-plane thermal conductivity is improved by 26.7% and the average thermal conductivity is improved by 19.1% (sample 9).

  Using a Vox-2 composition (sample 10) containing 43.5 wt% boron nitride material and 1.5 wt% carboxylated nanodiamond particles compared to a reference sample (sample 3) containing 45.0 wt% boron nitride filler This improves the in-plane thermal conductivity by 19.9% and the average thermal conductivity by 17.7%. When boron nitride is mixed with carboxylated nanodiamond powder (precursor for Vox D dispersion) mechanically as a dry powder to prepare similar compounds and the resulting composition is mixed, thermal conductivity It is not possible to detect improvement. When preparing the sample by mixing the fillers sequentially, ie first by mixing the carboxylated nanodiamond powder (Vox P) and then by mixing the boron nitride filler, the in-plane thermal conductivity of No improvement was obtained and only a slight improvement (1.1%) in average thermal conductivity could be measured.

  Use a Vox-2 composition (sample 11) containing 18.5 wt% boron nitride and 1.5 wt% carboxylated nanodiamond particles compared to a reference sample (sample 2) containing 20 wt% boron nitride filler Improves the in-plane thermal conductivity by 132% and the average thermal conductivity by 105%. A similar compound is prepared by mixing boron nitride with carboxylated nanodiamond powder (precursor for Vox D dispersion) mechanically as a dry powder, and the resulting composition is corresponding when mixed The improvement is that the in-plane thermal conductivity is 19.4% and the average thermal conductivity is 20.4%. When preparing samples by mixing the fillers sequentially, ie first by mixing the carboxylated nanodiamond powder (Vox P) and then by mixing the boron nitride filler, the in-plane thermal conductivity is It was measured that 6.8% was improved and that the average thermal conductivity was improved as well (6.8%).

  Using a hydrogen-2 composition (sample 12) containing 19.9 wt% boron nitride and 0.1 wt% hydrogen functionalized nanodiamond particles compared to a reference sample (sample 2) containing 20 wt% boron nitride filler This improves the in-plane thermal conductivity by 10.6% and the average thermal conductivity by 11.8%. A similar compound was prepared by mixing boron nitride with a hydrogen-functionalized nanodiamond powder (precursor for hydrogen D dispersion) as a dry powder on a machine, and when mixing the resulting composition, heat No improvement in conductivity can be detected.

  Compared to a reference sample (sample 3) containing 45.0 wt% boron nitride filler, a hydrogen-2 composition (sample 13) containing 44.9 wt% boron nitride and 0.1 wt% hydrogen functionalized nanodiamond particles is used. This improves the in-plane thermal conductivity by 15.9% and the average thermal conductivity by 9.6%. When preparing similar compounds by mixing boron nitride with hydrogen functionalized nanodiamond powder (precursor for hydrogen D dispersion) as a dry powder on the machine, the resulting composition is The corresponding improvement in inward thermal conductivity is 28.4% and the average thermal conductivity improvement is 18.8%. This result indicates that the hydrogen-terminated nanodiamond material particles may not have interacted with the surface of the boron nitride particles as electrostatically as the amino-functionalized nanodiamond particles and the carboxylic acid-functionalized nanodiamond particles. ing.

  Further improved thermal conductivity is based on the coupling effect generated by the surface of the nanodiamond material particles between the filler material and the parent polymer material. The improved wet state of the filler material particles and polymer obtained by using nano-diamond material particles with high thermal conductivity (forming the thermal composition) adhered to the surface of the filler material particles is undoubtedly the phonon Improve the thermal conductivity. Such an improvement is already obtained with a very low content of the composition.

  FIG. 1 is a PA-66 thermal composite with a total filler loading of 20% by weight, where the nanodiamond material was ball milled with hexagonal boron nitride as a dry powder. The content of nanodiamond in the compound is 1.5% by weight, and the content of hexagonal boron nitride is 18.5% by weight.

  FIG. 2 is a PA-66 thermal composite of the present invention with a total filler loading of 20 wt%, where nanodiamond material is introduced into the surface of hexagonal boron nitride in the form of a dispersion, The dispersion was dried to directly adhere the nanodiamond to the surface of the hexagonal boron nitride particles. The content of nanodiamond in the compound is 1.5% by weight, and the content of hexagonal boron nitride is 18.5% by weight.

Example 2 (according to the invention)
This example demonstrates the preparation of a thermally conductive and electrically insulating PA-66 composition.

Material Polyamide-66 (PA-66):
The PA-66 used in the test was PA-66 grade Zytel 135F (powder PA-66). This is commercially available.

Graphite:
The graphite used in this example is TIMCAL TIMREX® KS5-75TT Primary Synthetic Graphite and has the following particle sizes: D10: 9.1 μm; D50: 38.8 μm; D90: 70 μm.

Amino-functionalized nanodiamond mixture powder named Blend NH ₂ -P:
Zeta-positive amino-functionalized nanodiamond powder is a nanodiamond powder material developed by Carbodeon, which is prepared by exposing a commercially available nanodiamond mixture to pure ammonia gas at 700 ° C for 6 hours. It was. The nano-diamond particles of the suspension of the amino-functionalized nanodiamond mixture were detonated nanodiamond, and the base value measured by titration of the resulting amino-functionalized mixed material was 24.6 and the acid value was 1.7.

Amino-functionalized nanodiamond mixture suspension in water named Blend NH ₂ -S:
Zeta-positive amino-functionalized nanodiamond powder is a nanodiamond powder material developed by Carbodeon, obtained after exposure of a commercially available nanodiamond mixture to 700 ° C pure ammonia gas for 6 hours. The powder was prepared by suspending in water with the help of sonication for 1 hour (sonicator: Hielscher UP400S (from Hielscher)). The nano-diamond particles of the suspension of the amino-functionalized nanodiamond mixture were detonated nanodiamond, and the base value measured by titration of the resulting amino-functionalized mixed material was 24.6 and the acid value was 1.7. Although the nanodiamond content of this mixture varies between 50-70% by weight, the nanodiamond particle content does not significantly affect the stability of the suspension. The resulting zeta-positive amino-functionalized nanodiamond mixture aqueous suspension is a substantially stable suspension for at least 6 months, and the content of the mixture of amino-functionalized mixture suspension used is 1.5. % By weight.

Hydrogen functionalized nanodiamond mixture powder named Blend HP:
Zeta positive hydrogen functionalized nanodiamond powder is a nanodiamond powder material developed by Carbodeon that exposes a commercially available nanodiamond mixture to a 4% hydrogen gas flow (in argon) at 600 ° C. for 6 hours. Was prepared by The nanodiamond particles of the amino-functionalized nanodiamond dispersion were detonated nanodiamond, the base value measured by titration of the produced hydrogen functionalized mixed material was 19.1, and the acid value was 3.0.

Hydrogen functionalized nanodiamond mixture suspension in water named Blend HS:
Zeta positive hydrogen functionalized nanodiamond powder is a nanodiamond powder material developed by Carbodeon, which exposes a commercially available nanodiamond mixture to a 4% hydrogen gas flow (in argon) at 600 ° C. for 6 hours. The resulting powder was then prepared by suspending in water with the help of sonication for 1 hour (sonicator: Hielscher UP400S (from Hielscher)). The nanodiamond particles of the amino-functionalized nanodiamond dispersion were detonated nanodiamond, the base value measured by titration of the produced hydrogen functionalized mixed material was 19.1, and the acid value was 3.0. Although the nanodiamond content of this mixture varies between 50-70% by weight, the nanodiamond particle content does not significantly affect the stability of the suspension. The resulting zeta-positive amino-functionalized nanodiamond mixture suspension is a substantially stable suspension for at least 6 months, and the content of the amino-functionalized mixture suspension used is 1.5. % By weight.

Preparation of composition from nanodiamond mixture powder and graphite filler:
Blend N-1
Ball milling 21.78 g of graphite and 0.22 g of blended NH ₂ -P powder using a Retzch 100 PM100 ball milling tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide containers) Mixed with each other.

Blend H-1:
21.78 g of graphite and 0.22 g of blended HP powder are mixed together by ball milling using a Retzch 100 PM100 ball milling tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide container). did.

Preparation of composition from nanodiamond mixture suspension and graphite filler:
Blend N-2:
21.78 g of graphite and 14.67 ml of blend NH ₂ -S suspension (1.5 wt% aqueous suspension containing 0.22 g of solid) are mixed together and using a speed mixer device (Speed Mixer DAC 150.1 FV) Treated for 1 minute. The blend NH ₂ —S suspension spread evenly throughout the graphite matrix. The resulting mixture was dried overnight in an oven (80 ° C.) and the dried material was retzch 100 PM100 ball mill grinding tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide container) Was then used to obtain a composition in which the nanodiamond mixed material adhered well to the surface of the graphite particles.

Blend H-2:
21.78 g of graphite and 14.67 ml of blended HS suspension (1.5 wt% aqueous suspension containing 0.22 g of solid) are mixed together and processed for 1 minute using a speed mixer device (Speed Mixer DAC 150.1 FV) did. The blend NH ₂ —S suspension spread evenly throughout the graphite matrix. The resulting mixture was dried overnight in an oven (80 ° C.) and the dried material was retzch 100 PM100 ball mill grinding tool (30 minutes, 200 rpm; tungsten carbide balls (10 mm), tungsten carbide container) Was then used to obtain a composition in which the nanodiamond mixed material adhered well to the surface of the graphite particles.

Treatment All materials were dried and then mixed (PA-66: 2 hours in a dry air dryer / 120 ° C).

  Mixing was performed using an Xplore 15 microcompound and test specimens were injection molded using a Thermo-Haake Minijet. A special mold (25 x 25 x 3mm) for Minijet was used. After producing three similar composites for each series, the thermal conductivity and density were analyzed.

  Sample 40: Graphite powder and PA-66 thermoplastic polymer were placed in a compound to prepare a reference sample containing 50% by weight graphite material. The mixing and molding temperature was 290 ° C. The screw rotation speed during mixing was 100 rpm and the mixing time was at least 5 minutes. The mold temperature was 70 ° C. With the Minijet, the loading time at 800 bar was 5 seconds and the cooling time at 500 bar was 15 seconds.

  Samples 41-44: The compositions Blend N-1, Blend N-2, Blend H-1, Blend H-2, PA-66 thermoplastic polymer were mixed as indicated for Sample 40. The mixing and molding temperature was 290 ° C. The screw rotation speed during mixing was 100 rpm and the mixing time was at least 5 minutes. The mold temperature was 70 ° C. With the Minijet, the loading time at 800 bar was 5 seconds and the cooling time at 500 bar was 15 seconds. The total weight of the samples was 11 grams each and the total loading of the filler was 50% by weight. The graphite filler loading was 49.5% by weight of the total weight of the sample and the blend composition loading was 0.5% by weight of the total weight of the sample.

Results The results are summarized in Table 2. Error of the density measurement is ± 0.002g / cm ^3, the error of the thermal diffusivity measuring is ± 5%, the error of the calculated C _P is 15% or less. Since the specific heat value of each sample is the same in the x, y, and z directions, only one value is shown for each sample.

  The results show that both in-plane (x and y) thermal conductivity and through-plane thermal conductivity can be significantly improved by the slight addition of nanodiamond-containing composition. Also, the method of introducing the nanodiamond material into the compound has a significant impact on the final thermal conductivity properties of the product.

  After the nanodiamond filler is ground by ball milling with boron nitride filler, the resulting filler mixture is incorporated into the thermoplastic polymer itself, compared to a method in which the filler is added separately to the thermoplastic matrix. It has been previously shown that conductivity is improved. Compared to a reference sample containing 50.0 wt% graphite filler (Sample 40), the composite containing 49.5 wt% graphite filler and 0.5 wt% blend N-1 composition has in-plane thermal conductivity. 15.1% improvement and average thermal conductivity improved by 13.9% (Sample 41). This result is in very good agreement with that obtained by replacing the graphite filler with a similar level of blended H-1 composition, in which case it is compared to a reference sample containing 50% by weight of graphite. The improvement in the in-plane thermal conductivity was 14.9% and the average thermal conductivity was 15.3% (Sample 43).

  A similar composite (Sample 42) containing 49.5 wt% graphite filler and 0.5 wt% blend N-2 composition with improved adhesion of the nanodiamond blend material to the graphite particles was 50 wt% Compared with a reference sample containing graphite, the in-plane thermal conductivity was improved by 34.3% and the average thermal conductivity was improved by 32.7%. The improvement in thermal conductivity is over 100% compared to a blend of graphite filler and the same blend N filler in the dry state (sample 41). In addition, a similar composite (Sample 44) containing 49.5 wt% graphite filler and 0.5 wt% and blend H-2 composition with improved adhesion of the nanodiamond blend material to the graphite particles is 50 Compared to a reference sample containing weight percent graphite, the in-plane thermal conductivity was improved by 30.7% and the average thermal conductivity was improved by 25.4%. Again, an almost 100% improvement in thermal conductivity was obtained compared to a blend of graphite filler and the same blend N filler in the dry state (sample 43). This clearly shows the importance of the nanodiamond material being distributed on the surface of other filler materials.

  Further improvements in thermal conductivity are based at least in part on the coupling effect produced by the nanodiamond material between the filler material and the parent polymer material. The improved wet state of the filler material particles and polymer obtained by using thermally conductive nanodiamond material particles (forming the thermal composition) bonded to the surface of the filler material particles is undoubtedly the phonon's Improves migration and thus improves thermal conductivity. Improvements are already obtained with a very low content of the composition.

Claims (61)

A method for producing a composition comprising at least one filler and a nanodiamond material, comprising:
(I) contacting the nanodiamond material-containing liquid medium with at least one filler to form a suspension;
(Ii) removing the liquid medium from the suspension of step (i) to produce a composition comprising at least one filler and a nanodiamond material.   The method of claim 1, wherein the nanodiamond material-containing liquid medium of step (i) is in the form of a dispersion.   The method of claim 1, wherein the nanodiamond material-containing liquid medium of step (i) is in the form of a suspension.   The liquid medium is selected from the group consisting of a polar protic solvent, a polar aprotic solvent, a dipolar aprotic solvent, an organic solvent, and a mixture of these solvents. The method described in 1.   The polar protic solvent is water, alcohol, linear aliphatic diol, branched diol, or carboxylic acid, and the polar aprotic solvent is dichloromethane, tetrahydrofuran, propylene carbonate, or lactam. The dipolar aprotic solvent is any one of ketone, ester, N, N-methylformamide, and dimethyl sulfoxide, and the organic solvent is toluene or other aromatic solvent. Method.   The liquid medium is selected from water, methanol, ethanol, iso-propanol, linear aliphatic diol, branched diol, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), dimethyl 6. A process according to claim 4 or 5 carried out from the group consisting of sulfoxide (DMSO), any mixture of these solvents.   The filler is selected from the group consisting of metals, metal oxides, metal nitrides, metal carbides, carbon compounds, silicon compounds, boron compounds (eg, boron nitride), ceramic materials, natural fibers, and combinations thereof. The method of any one of Claims 1-6.   The carbon compound is selected from diamond materials other than detonated diamond, graphite, carbon black, carbon fiber, graphene, oxidized graphene, soot, carbon nanotube, pyrolytic carbon, silicon carbide, aluminum carbide, carbon nitride, The method according to claim 7, wherein the method is performed from a group consisting of these combinations.   8. The method of claim 7, wherein the boron compound is selected from the group consisting of hexagonal boron nitride, cubic boron nitride, boron carbide, and combinations thereof.   10. In step (i), the nanodiamond material-containing liquid medium is mechanically mixed with at least one filler, preferably the mixing is performed using a speed mixer. The method described in 1.   11. A method according to any one of the preceding claims, wherein a mass of the composition is formed by mechanically breaking the composition, wherein the mechanical treatment is preferably bead milling.   12. A method according to any preceding claim, wherein the nanodiamond material substantially adheres to the surface of the at least one filler.   The method according to claim 1, wherein the nanodiamond material has a zeta potential value of greater than ± 35 mV when dispersed in water.   14. A method according to claim 12 or 13, wherein the size of the mass of adhered nanodiamond material particles is less than 500 nm, preferably less than 300 nm, more preferably less than 100 nm, most preferably less than 50 nm.   15. A method according to any one of the preceding claims, wherein the nanodiamond material on the surface of the filler can generate a coupling effect for another material.   The method of claim 15, wherein the selection of the other material is made from the group consisting of a polymer, a metal, a ceramic material, and mixtures thereof. A method for producing a nanodiamond material-containing thermal composite comprising:
(I) contacting the nanodiamond material-containing liquid medium with at least one filler to form a suspension;
(Ii) removing the liquid medium from the suspension of step (i) to produce a composition comprising at least one filler and a nanodiamond material;
(Iii) A method comprising the step of mixing the composition of step (ii) with at least one polymer to form a nanodiamond material-containing thermal composite.   18. The method of claim 17, wherein the nanodiamond material-containing liquid medium of step (i) is in the form of a dispersion.   18. The method of claim 17, wherein the nanodiamond material-containing liquid medium of step (i) is in the form of a suspension.   20. The liquid medium is selected from the group consisting of polar protic solvents, polar aprotic solvents, dipolar aprotic solvents, organic solvents, and mixtures of these solvents. The method described in 1.   The polar protic solvent is water, alcohol, linear aliphatic diol, branched diol, or carboxylic acid, and the polar aprotic solvent is dichloromethane, tetrahydrofuran, propylene carbonate, or lactam. The dipolar aprotic solvent is any one of ketone, ester, N, N-methylformamide, and dimethyl sulfoxide, and the organic solvent is toluene or another aromatic solvent. Method.   The liquid medium is selected from water, methanol, ethanol, iso-propanol, linear aliphatic diol, branched diol, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), dimethyl 22. A process according to claim 20 or 21 carried out from the group consisting of sulfoxide (DMSO), any mixture of these solvents.   The filler is selected from the group consisting of metals, metal oxides, metal nitrides, metal carbides, carbon compounds, silicon compounds, boron compounds (eg, boron nitride), ceramic materials, natural fibers, and combinations thereof. The method according to any one of claims 17 to 22.   The carbon compound is selected from diamond materials other than detonated diamond, graphite, carbon black, carbon fiber, graphene, oxidized graphene, soot, carbon nanotube, pyrolytic carbon, silicon carbide, aluminum carbide, carbon nitride, 24. The method of claim 23, wherein the method is performed from a group consisting of these combinations.   24. The method of claim 23, wherein the boron compound is selected from the group consisting of hexagonal boron nitride, cubic boron nitride, boron carbide, and combinations thereof.   26. In step (i), the nanodiamond material-containing liquid medium is mechanically mixed with at least one filler, preferably the mixing is performed using a speed mixer. The method described in 1.   27. Any of claims 18-26, wherein the bulk of the filler is formed by mechanically breaking the composition of step (ii) prior to step (iii), wherein the mechanical treatment is preferably bead milling. The method according to claim 1.   28. A method according to any one of claims 17 to 27, wherein the nanodiamond material substantially adheres to the surface of the at least one filler.   29. A method according to any one of claims 17 to 28, wherein the value of the zeta potential of the nanodiamond material exceeds ± 35mV when dispersed in water.   30. A method according to claim 28 or 29, wherein the size of the clumps of adhered nanodiamond material particles is less than 500 nm, preferably less than 300 nm, more preferably less than 100 nm, most preferably less than 50 nm.   31. A method according to any one of claims 17 to 30, wherein the nanodiamond material on the surface of the filler is capable of generating a coupling effect on another material.   32. Any of the claims 17-31, wherein the at least one polymeric material is selected from the group consisting of epoxy, silicone, thermoplastic polymer, acrylate, polyurethane, polyester, fluoropolymer, siloxane, polyimide, and mixtures thereof. The method according to claim 1.   0.01 to 80% by weight of nanodiamond material and 1 to 99.99% by weight of at least one filler, wherein the nanodiamond material is substantially adhered to the surface of the at least one filler. Composition.   34. The composition of claim 33, wherein the active surface area of the composition is less than the active surface area of the composition wherein the nanodiamond material is not substantially adhered to the surface of at least one filler.   35. The composition of claim 34, wherein the active surface area of the composition is at least 5% less than the active surface area of the composition wherein the nanodiamond material is not substantially adhered to the surface of at least one filler.   36. Composition according to any one of claims 33 to 35, comprising 0.01 to 40% by weight, preferably 0.01 to 20% by weight, more preferably 0.01 to 5% by weight of nanodiamond material.   37. Any one of claims 33 to 36, comprising 10 to 90 wt%, preferably 15 to 85 wt%, more preferably 15 to 70 wt%, most preferably 20 to 50 wt% of at least one filler. The composition according to item.   The filler is selected from the group consisting of metals, metal oxides, metal nitrides, metal carbides, carbon compounds, silicon compounds, boron compounds (eg, boron nitride), ceramic materials, natural fibers, and combinations thereof. The composition according to any one of claims 33 to 37.   The carbon compound is selected from diamond materials other than detonated diamond, graphite, carbon black, carbon fiber, graphene, oxidized graphene, soot, carbon nanotube, pyrolytic carbon, silicon carbide, aluminum carbide, carbon nitride, 40. The composition of claim 38, performed from the group consisting of combinations thereof.   39. The composition of claim 38, wherein the boron compound is selected from the group consisting of hexagonal boron nitride, cubic boron nitride, boron carbide, and combinations thereof.   41. The average size of the main particles of the nanodiamond material particles is 1 nm to 10 nm, preferably 2 nm to 8 nm, more preferably 3 nm to 7 nm, and most preferably 4 nm to 6 nm. The composition as described.   42. The composition according to any one of claims 33 to 41, wherein the average size of the primary particles of the at least one filler is 10 nm to 2000 [mu] m, preferably 50 nm to 500 [mu] m, more preferably 500 nm to 200 [mu] m.   43. Composition according to any one of claims 33 to 42, wherein the size of the clumps of adhered nanodiamond material particles is less than 500 nm, preferably less than 300 nm, more preferably less than 100 nm, and most preferably less than 50 nm.   44. A composition according to any one of claims 33 to 43, wherein the nanodiamond material on the surface of the filler is capable of generating a coupling effect on another material.   45. The composition of claim 44, wherein the selection of said another material is made from the group consisting of polymers, metals, ceramic materials, and mixtures thereof.   46. A composition according to any one of claims 33 to 45, wherein the value of zeta potential of the nanodiamond material exceeds ± 35mV when dispersed in water.   Comprising 0.01 to 80% by weight of nanodiamond material, 1 to 90% by weight of at least one filler, and 5 to 95% by weight of at least one polymer, wherein said nanodiamond material is said at least one kind Nanodiamond-containing thermal composite substantially adhered to the surface of the filler.   48. The nanodiamond-containing heat of claim 47, wherein the average thermal conductivity is at least 5% greater than the average thermal conductivity of a composite in which the nanodiamond material is not substantially adhered to the surface of at least one filler. Complex.   The average thermal conductivity is at least 20%, preferably 50%, more preferably 70% greater than the average thermal conductivity of a composite in which the nanodiamond material is not substantially adhered to the surface of at least one filler. 48. The nanodiamond-containing thermal composite according to claim 47.   The nanodiamond-containing thermal composite according to any one of claims 47 to 49, comprising 0.01 to 40 wt%, preferably 0.01 to 20 wt%, more preferably 0.01 to 5 wt% of the nanodiamond material.   51. The nanodiamond-containing thermal composite according to any one of claims 47 to 50, comprising 10 to 70% by weight, preferably 10 to 50% by weight, more preferably 15 to 45% by weight, of the at least one filler. body.   52. The nanodiamond-containing thermal composite according to any one of claims 47 to 51, comprising 20 to 90% by weight, preferably 50 to 85% by weight, of the at least one polymer.   53. The selection of any of claims 47 to 52, wherein the at least one polymeric material is selected from the group consisting of epoxy, silicone, thermoplastic polymer, acrylate, polyurethane, polyester, fluoropolymer, siloxane, polyimide, and mixtures thereof. The nanodiamond-containing thermal composite according to claim 1.   The filler is selected from the group consisting of metals, metal oxides, metal nitrides, metal carbides, carbon compounds, silicon compounds, boron compounds (eg, boron nitride), ceramic materials, natural fibers, and combinations thereof. The nanodiamond-containing thermal composite according to any one of claims 47 to 53.   The carbon compound is selected from diamond materials other than detonated diamond, graphite, carbon black, carbon fiber, graphene, oxidized graphene, soot, carbon nanotube, pyrolytic carbon, silicon carbide, aluminum carbide, carbon nitride, 55. The nanodiamond-containing thermal composite according to claim 54, wherein the thermal composite is performed from the group consisting of these combinations.   55. The nanodiamond-containing thermal composite according to claim 54, wherein the boron compound is selected from the group consisting of hexagonal boron nitride, cubic boron nitride, boron carbide, and combinations thereof.   57. The average size of the main particles of the nanodiamond material particles is 1 nm to 10 nm, preferably 2 nm to 8 nm, more preferably 3 nm to 7 nm, and most preferably 4 nm to 6 nm. The nanodiamond-containing thermal composite as described.   58. The nanodiamond-containing material according to any one of claims 47 to 57, wherein an average size of main particles of the at least one filler is 10 nm to 2000 μm, preferably 50 nm to 500 μm, more preferably 500 nm to 200 μm. Thermal complex.   59. Nanodiamond-containing according to any one of claims 47 to 58, wherein the size of the clumps of adhered nanodiamond material particles is less than 500 nm, preferably less than 300 nm, more preferably less than 100 nm, and most preferably less than 50 nm. Thermal complex.   60. The nanodiamond-containing thermal composite according to any one of claims 47 to 59, wherein the nanodiamond material on the surface of the filler can generate a coupling effect to another material.   61. The nanodiamond-containing thermal composite according to any one of claims 47 to 60, wherein the value of zeta potential of the nanodiamond material exceeds ± 35 mV when dispersed in water.