JP2009107857A - Dispersible silica nano hollow particles and method for producing dispersion liquid of silica nano hollow particles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide dispersible silica nano hollow particles and a method for producing the dispersion liquid of silica nano hollow particles wherein the coagulation of the silica nano hollow particles comprising a silica shell is prevented and the silica nano hollow particles can be dispersed in a solvent, a molten resin and the like as fine coagulated particles and can be mixed as a solid component in large amounts. <P>SOLUTION: The high concentration dispersion liquid 5 of the silica nano hollow particles 1 consisting of the silica shell can be obtained by such steps that a step (S10) where n-hexane and a surface modifier are added to the silica nano hollow particles 1, stirred and dispersed with a high-speed stirrer, a step (S11) to obtain the fine coagulated particles having a size of about 0.5 μm or less by strong dispersion in a wet jet mill, a step (S12) for concentration in an evaporator, a step (S13) for performing surface modification in an autoclave at a supercritical state of n-hexane, steps (S14, S15) for redispersion by stirring and dispersing with the high-speed stirrer, a step (S16) to add a denatured silicone oil into a dispersed liquid, a step (S17) for performing ultrasonic dispersion by an ultrasonic dispersing machine and a step (S18) for performing classification and filtration. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a dispersible silica nanohollow particle in which a nanohollow particle composed of a silica shell having an outer diameter in a range of approximately 30 nm to approximately 300 nm (hereinafter also referred to as “silica nanohollow particle”) is provided with dispersibility. And a method for producing a dispersion of hollow silica nano particles.

  In recent years, as part of nanotechnology research, applied research on fine particles having a particle size of several hundred nanometers or less has been actively conducted. As an example, there is an invention of highly dispersed silica nano hollow particles described in Patent Document 1 and a method for producing the same. This nano hollow particle is a nano hollow particle composed of a dense silica shell, in which pores of 2 nm to 20 nm are not detected in the pore distribution, and the first step of adjusting calcium carbonate is coated with silica. It is produced by the second step, a third step in which calcium carbonate is dissolved to form nano hollow particles.

The highly dispersed silica nano hollow particles according to Patent Document 1 are hollow and have a thin silica shell, so that they have excellent heat insulating properties and transparency. As shown in Patent Document 2, they are uniform in paints, films, and synthetic fibers. By disperse in the composition, it is possible to obtain a heat insulating paint, heat insulating film, and heat insulating fiber, which can be applied to a wide range of technical fields. In addition, various applications are expected.
JP 2005-263550 A JP 2007-070458 A

  However, since the highly dispersed silica nano hollow particles described in Patent Document 1 are fine particles having an outer diameter of about 30 nm to about 300 nm, they are likely to agglomerate and melt even in a solvent such as water or an organic solvent. Even when mixed in resin, it is immediately aggregated into huge aggregated particles with a size of several to several tens of μm. It is actually dispersed uniformly as fine aggregated particles in paints, films, and synthetic fibers. Since the above is difficult, there is a problem that it is not possible to make full use of excellent properties such as heat insulation and transparency.

  Therefore, the present invention prevents aggregation of silica nano hollow particles, can be easily dispersed as fine aggregate particles in a solvent such as water or an organic solvent, a molten resin, etc., and a larger amount as a solid content. It is an object of the present invention to provide a dispersible silica nano hollow particle that can be mixed and a method for producing a dispersion of silica nano hollow particles.

  The dispersible silica nano hollow particles according to the invention of claim 1 are dispersible silica nano hollow particles in which nano hollow particles composed of a silica shell having an outer diameter in a range of about 30 nm to about 300 nm can be easily finely dispersed in a solvent. In addition, an organic solvent and a surface modifier are added to the nano hollow particles made of the silica shell and dispersed strongly by a wet jet mill, and the surface modifier is reacted and added to the nano hollow particles made of the silica shell. By modification, the nano hollow particles made of the silica shell are finely dispersed and powdered.

 Here, as the “organic solvent”, aliphatic alcohols such as methanol, ethanol and propanol, aliphatic hydrocarbons such as n-hexane, aromatic hydrocarbons such as xylene, and the like can be used. In addition, examples of the “surface modifier” include isocyanate compounds, amine compounds, vinyl compounds, epoxy compounds, methacryloxy compounds, acrylic compounds, imide compounds, compounds having an alkyl group, compounds having an aryl group, etc. Alternatively, modified silicone oils such as monoamine-modified silicone oil and polyether-modified silicone oil can be used.

  Furthermore, specific examples of the “wet jet mill” include a nanomizer manufactured by SG Engineering Co., Ltd., an ultra-high pressure homogenizer LAB2000 manufactured by SMT Co., Ltd., an optimizer manufactured by Sugino Machine Co., Ltd., etc. Can be used. In the present invention, those with “substantially” added to the numerical value do not appear as the critical value or the boundary value, but the numerical value is regarded as an approximate value.

  The dispersible silica nano hollow particles according to the invention of claim 2 have the frequency distribution (intensity distribution) of the dispersive silica nanohollow particles when the particle size distribution is measured by the dynamic light scattering method after being dispersed in the solvent. All fall within the range of 110 nm to 550 nm, and the peak of the particle size distribution due to the frequency distribution (intensity distribution) exists within the range of 200 nm to 350 nm.

  Here, the “dynamic light scattering method” is a method for measuring the particle size of fine particles by applying diffraction and scattering of laser light, and is also called a non-contact backscattering method for measuring the particle size distribution of fine particles. Technology.

  The dispersible silica nano hollow particle according to the invention of claim 3 is the structure of claim 1 or claim 2, wherein the surface modification is performed by using the nano hollow particle composed of a silica shell strongly dispersed by the wet jet mill and the organic The surface modifier is reacted and added to the surface of the nano-hollow particles composed of the silica shell as a supercritical state of the organic solvent by applying high temperature and high pressure to the mixture of the solvent and the surface modifier.

  The dispersible silica nano-hollow particles according to the invention of claim 4 are, in the configuration of claim 3, a supercritical state of the organic solvent by applying high temperature and high pressure to the mixture using an autoclave.

  The dispersible silica nano hollow particles according to the invention of claim 5 are the structures according to any one of claims 2 to 4, wherein the surface modifier is an isocyanate compound. Here, the “isocyanate compound” means a compound having one or more isocyanate groups (—N═C═O), a triisocyanate compound in which three isocyanate groups are bonded to an alkyl group, and triethoxypropyl isocyanate silane. A compound such as (TEIS) can be used.

  A dispersible silica nano hollow particle according to the invention of claim 6 is the structure of claim 2, wherein the surface modifier is a modified silicone oil, and the surface modification is made of the silica shell by the wet jet mill. Is strongly dispersed, and the surface modifier is reactively added to the surface of the nano hollow particles made of the silica shell.

  The dispersible silica nano hollow particle according to the invention of claim 7 is the structure of claim 6 wherein the modified silicone oil is a modified silicone oil into which a hydrophilic organic group is introduced. Here, examples of the “hydrophilic organic group” include a polyether group, an ethoxy group, and a carboxyl group.

  The dispersible silica nano hollow particle according to the invention of claim 8 is the structure of claim 6, wherein the modified silicone oil is a modified silicone oil into which a lipophilic organic group is introduced. Here, examples of the “lipophilic organic group” include a monoamine group, an amino group, and an alkyl group.

 The method for producing a dispersion of silica nano-hollow particles according to the invention of claim 9 is a dispersion of nano-hollow particles composed of silica shells having an outer diameter in a range of approximately 30 nm to approximately 300 nm in a solvent. In the production method, when the particle size distribution is measured by the dynamic light scattering method after being dispersed in the solvent, all of the frequency distribution (intensity distribution) falls within the range of 110 nm to 550 nm, and the frequency distribution ( A peak of the particle size distribution due to the intensity distribution) is in the range of 200 nm to 350 nm, and an organic solvent and a surface modifier are added to the nano hollow particles made of the silica shell and dispersed strongly by a wet jet mill; A step of reacting and adding the surface modifier to the surface of the nano-hollow particles composed of the silica shell, and the surface-modified nano-hollow particles composed of the silica shell are dissolved in the solution. A step of to again finely dispersed and mixed in a step of adding a modified silicone oil in the solvent, those comprising the step of ultrasonically dispersed by an ultrasonic disperser.

 Here, the “solvent” includes both water and an organic solvent, and the organic solvent includes aliphatic alcohols such as methanol, ethanol, and propanol, aliphatic hydrocarbons such as n-hexane, and aromatic carbonization such as xylene. Including hydrogen, etc. As the “organic solvent”, aliphatic alcohols such as methanol, ethanol and propanol, aliphatic hydrocarbons such as n-hexane, aromatic hydrocarbons such as xylene, and the like can be used. Furthermore, as the “surface modifier”, an isocyanate compound, an amine compound, a vinyl compound, an epoxy compound, a methacryloxy compound, an acrylic compound, an imide compound, a compound having an alkyl group, a compound having an aryl group, Etc. can be used.

 Furthermore, specific examples of the “wet jet mill” include a nanomizer manufactured by SG Engineering Co., Ltd., an ultra-high pressure homogenizer LAB2000 manufactured by SMT Co., Ltd., an optimizer manufactured by Sugino Machine Co., Ltd., etc. Can be used. In the present invention, those with “substantially” added to the numerical value do not appear as the critical value or the boundary value, but the numerical value is regarded as an approximate value.

  The method for producing a dispersion of silica nano-hollow particles according to the invention of claim 10 is the structure of claim 9, wherein the step of modifying the surface comprises nano-hollow particles comprising the silica shell, the organic solvent, and the surface modifier. In this step, the surface modifier is reacted and added to the surface of the nano-hollow particles composed of the silica shell by applying high temperature and high pressure to the mixture to obtain a supercritical state of the organic solvent.

  The method for producing a dispersion of nano-hollow particles comprising silica shells according to the invention of claim 11 is characterized in that, in the structure of claim 10, in the step of surface modification, high temperature and high pressure are applied to the mixture using an autoclave. The solvent is in a supercritical state.

  The dispersible silica nano hollow particles according to the invention of claim 1 are dispersible silica nano hollow particles in which nano hollow particles composed of a silica shell having an outer diameter in a range of about 30 nm to about 300 nm can be easily dispersed in a solvent. In addition, an organic solvent and a surface modifier are added to nano hollow particles made of silica shell and dispersed strongly by a wet jet mill, and surface modification is carried out by reaction addition of the surface modifier to nano hollow particles made of silica shell. Nano hollow particles made of silica shells are finely dispersed and powdered.

 Here, as the “organic solvent”, aliphatic alcohols such as methanol, ethanol and propanol, aliphatic hydrocarbons such as n-hexane, aromatic hydrocarbons such as xylene, and the like can be used. In addition, examples of the “surface modifier” include isocyanate compounds, amine compounds, vinyl compounds, epoxy compounds, methacryloxy compounds, acrylic compounds, imide compounds, compounds having an alkyl group, compounds having an aryl group, etc. Alternatively, modified silicone oils such as monoamine-modified silicone oil and polyether-modified silicone oil can be used. Furthermore, specific examples of the “wet jet mill” include a nanomizer manufactured by SG Engineering Co., Ltd., an ultra-high pressure homogenizer LAB2000 manufactured by SMT Co., Ltd., an optimizer manufactured by Sugino Machine Co., Ltd., etc. Can be used.

 Even if nano hollow particles made of silica shell having an outer diameter in the range of about 30 nm to about 300 nm are to be dispersed in a solvent such as an organic solvent, a typical stirrer or a disperser has a huge size of several μm to several tens of μm. It is difficult to disperse nano hollow particles composed of silica shells aggregated into aggregated particles into fine aggregated particles on the order of several hundred nm. Therefore, first, an organic solvent and a surface modifier are added, and strong stirring and dispersion are performed with a wet jet mill to finely disperse most of the nano hollow particles made of silica shells.

  Then, the surface is modified by reacting and adding a surface modifier to the nano hollow particles made of silica shell. By surface modification in this manner, the dispersibility of nano hollow particles made of silica shells is improved, and nano hollow particles made of finely dispersed silica shells do not easily reaggregate, and almost all Nano hollow particles made of silica shells are finely dispersed to form fine agglomerated particles having an outer diameter of several hundred nm. By removing the solvent by drying or the like in this state, powdery dispersible silica nano hollow particles are obtained.

  The dispersible silica nano hollow particles thus obtained are dispersed in a solvent such as water or an organic solvent (including a solvent for an aqueous paint or a solvent-based paint) since the periphery of the fine aggregated particles is surface-modified with a surface modifier. Even in this case, it is possible to disperse into fine agglomerated particles without agglomeration only by stirring with a normal agitator, and even when mixed in molten resin, etc. It can mix in the state disperse | distributed to particle | grains.

In addition, the nano hollow particles made of silica shell have a very large specific surface area of about 150 m ² / g, so that only a small percentage by weight could be mixed even if it was mixed with paint or molten resin. . This large specific surface area value is presumed to be due to the presence of fine irregularities at the molecular level on the surface of the nano hollow particles made of silica shells. However, it is presumed that fine surface irregularities are filled with surface modifiers by surface modification, and the specific surface area is reduced. As a result, it is possible to mix a larger amount of silica nano hollow particles than the case of mixing giant aggregated particles of several μm to several tens of μm in spite of mixing in a state of being dispersed in fine aggregated particles. it can.

  In addition, when the same amount is mixed, when the aggregated large aggregated particles are mixed, the transparency of the silica nano hollow particles is not utilized, so it becomes cloudy white without becoming transparent. When the particles are mixed, the transparency of the silica nano hollow particles is utilized to obtain a silica nano hollow particle dispersed solvent, a silica nano hollow particle dispersed paint, a silica nano hollow particle dispersed resin, and the like having excellent transparency.

 In this way, the silica nano hollow particles can be prevented from agglomerating, and can be easily dispersed as fine agglomerated particles in a solvent such as water or an organic solvent, or a molten resin, and a larger amount can be added as a solid content. Dispersible silica nano hollow particles can be mixed.

  In the dispersible silica nano hollow particles according to the invention of claim 2, when the particle size distribution is measured by a dynamic light scattering method after being dispersed in a solvent, the entire frequency distribution (intensity distribution) is in the range of 110 nm to 550 nm. The particle size distribution peak due to the frequency distribution (intensity distribution) falls within the range of 200 nm to 350 nm.

  Here, the “dynamic light scattering method” is a method for measuring the particle size of fine particles by applying diffraction and scattering of laser light, and is also called a non-contact backscattering method for measuring the particle size distribution of fine particles. Technology.

 Nano hollow particles composed of silica shells having an outer diameter in the range of approximately 30 nm to approximately 300 nm have an average particle diameter of approximately 70 nm. However, since these are fine particles, when dispersed in a solvent or the like, The particles immediately aggregated to form giant aggregated particles having a size of several μm to several tens of μm, and could not be dispersed into fine aggregated particles of several hundred nm.

  Therefore, as described above, the inventors have succeeded in dispersing the fine aggregated particles by surface modification or the like, but when the particle size distribution is measured by a dynamic light scattering method by dispersing in a solvent, Based on this finding, all of the frequency distribution (intensity distribution) falls within the range of 110 nm to 550 nm, and the particle size distribution peak due to the frequency distribution (intensity distribution) exists within the range of 200 nm to 350 nm. The present invention has been completed.

  Such a fine and sharp particle size distribution could not be obtained at all in the conventional hollow nanoparticle made of silica shell, and can be said to be an epoch-making technique. Moreover, as described above, since the specific surface area is small while having such a fine particle size distribution, a larger amount can be mixed into the base material, and the silica shell including heat insulation and transparency can be mixed. The characteristics of the nano hollow particles made of can be sufficiently exhibited.

 In this way, the silica nano hollow particles can be prevented from agglomerating, and can be easily dispersed as fine agglomerated particles in a solvent such as water or an organic solvent, or a molten resin, and a larger amount can be added as a solid content. Dispersible silica nano hollow particles can be mixed.

  In the dispersible silica nano hollow particles according to the invention of claim 3, the surface modification is performed by applying high temperature and high pressure to a mixture of nano hollow particles composed of silica shells strongly dispersed by a wet jet mill, an organic solvent and a surface modifier. As a supercritical state of the organic solvent, a surface modifier is reacted and added to the surface of the hollow nanoparticle made of silica shell.

  By setting the supercritical state of the organic solvent, the organic solvent freely enters between the aggregated particles together with the surface modifier, and the surface modifier is reactively added to the entire surface of the fine aggregated particles. For this reason, even if it performs powerful stirring and dispersion | distribution with a wet jet mill, each surface of the silica nano hollow particle which does not disperse | distribute to a fine aggregation particle but remains as a huge aggregation particle | grain can be surface-modified. Therefore, the operating conditions of the wet jet mill can be relaxed, and almost all silica nano hollow particles can be finely dispersed.

 In this way, the silica nano hollow particles can be prevented from agglomerating, and can be easily dispersed as fine agglomerated particles in a solvent such as water or an organic solvent, or a molten resin, and a larger amount can be added as a solid content. Dispersible silica nano hollow particles can be mixed.

  In the dispersible silica nano hollow particles according to the invention of claim 4, the mixture is brought to a supercritical state of the organic solvent by applying high temperature and high pressure to the mixture using an autoclave.

  To bring the organic solvent into the supercritical state and allow the organic solvent to freely enter the aggregated particles of the aggregated silica nano hollow particles together with the surface modifier, it is necessary to apply high temperature and high pressure to the mixture of the organic solvent and the surface modifier. However, by using an autoclave, high temperature and high pressure can be applied safely and freely, and a surface modifier can be reacted and added to the entire surface of the finely-agglomerated particles of silica nano hollow particles.

 In this way, the silica nano hollow particles can be prevented from agglomerating, and can be easily dispersed as fine agglomerated particles in a solvent such as water or an organic solvent, or a molten resin, and a larger amount can be added as a solid content. Dispersible silica nano hollow particles can be mixed.

  In the dispersible silica nano hollow particles according to the invention of claim 5, the surface modifier is an isocyanate compound. Here, the “isocyanate compound” means a compound having one or more isocyanate groups (—N═C═O), a triisocyanate compound in which three isocyanate groups are bonded to an alkyl group, and triethoxypropyl isocyanate silane. A compound such as (TEIS) can be used.

 As a result of earnest experimental research on the types of surface modifiers that are most suitable as surface modifiers for surface modification as a supercritical state of an organic solvent, the present inventors have found that when isocyanate compounds are used, It has been found that a good dispersion state can be obtained, and the present invention has been completed based on this finding.

 In this way, the silica nano hollow particles can be prevented from agglomerating, and can be easily dispersed as fine agglomerated particles in a solvent such as water or an organic solvent, or a molten resin, and a larger amount can be added as a solid content. Dispersible silica nano hollow particles can be mixed.

  In the dispersible silica nano-hollow particles according to the invention of claim 6, the surface modifier is a modified silicone oil, and the surface modification is performed by strongly dispersing the nano-hollow particles composed of silica shells with a wet jet mill and using the surface modifier. Reaction is added to the surface of nano hollow particles made of silica shell.

 Thus, by using modified silicone oil as a surface modifier, silica nano hollow particles are finely dispersed by adding an organic solvent and a surface modifier to nano hollow particles made of silica shell and dispersing them strongly with a wet jet mill. At the same time, the modified silicone oil can be reactively added to the surface for surface modification. Since the surface-modified silica nano hollow particles are not easily re-agglomerated, nano hollow particles composed of almost all silica shells are finely dispersed to form fine agglomerated particles having an outer diameter of several hundred nm. By drying and removing the organic solvent in this state, powdery dispersible silica nano hollow particles can be obtained.

  The dispersible silica nano hollow particles thus obtained are dispersed in a solvent such as water or an organic solvent (including a solvent for an aqueous paint or a solvent-based paint) since the periphery of the fine aggregated particles is surface-modified with a surface modifier. Even in this case, it is possible to disperse the fine agglomerated particles without agglomeration only by stirring with a normal agitator. In addition, even when mixed in a molten resin, the fine agglomerated particles are dispersed without agglomeration. It can be mixed in the state.

In addition, the nano hollow particles made of silica shell have a very large specific surface area of about 150 m ² / g, so that only a small percentage by weight could be mixed even if it was mixed with paint or molten resin. . This large specific surface area value is presumed to be due to the presence of fine irregularities at the molecular level on the surface of the nano hollow particles made of silica shells. However, it is presumed that fine surface irregularities are filled with surface modifiers by surface modification, and the specific surface area is reduced. As a result, it is possible to mix a larger amount of silica nano hollow particles than the case of mixing giant aggregated particles of several μm to several tens of μm in spite of mixing in a state of being dispersed in fine aggregated particles. it can.

  In addition, when the same amount is mixed, when the aggregated giant aggregated particles are mixed, the transparency of the silica nano hollow particles is not utilized, and thus it becomes cloudy white without becoming transparent. When hollow particles are mixed, the transparency of silica nano hollow particles is utilized, and silica nano hollow particle dispersion solvents, silica nano hollow particle dispersion paints, silica nano hollow particle dispersion resins and the like having excellent transparency can be obtained.

 In this way, the silica nano hollow particles can be prevented from agglomerating, and can be easily dispersed as fine agglomerated particles in a solvent such as water or an organic solvent, or a molten resin, and a larger amount can be added as a solid content. Dispersible silica nano hollow particles can be mixed.

  In the dispersible silica nano hollow particles according to the invention of claim 7, the modified silicone oil is a modified silicone oil into which a hydrophilic organic group is introduced. Here, examples of the “hydrophilic organic group” include a polyether group, an ethoxy group, and a carboxyl group.

  Thus, by modifying the surface with a modified silicone oil having a hydrophilic organic group introduced, the dispersible silica nano hollow particles are aggregated only by stirring with a normal stirring device when dispersed in water or an aqueous paint. It can be easily dispersed as fine aggregated particles, and a larger amount can be mixed, and the properties such as heat insulation and transparency of the silica nano hollow particles can be sufficiently exhibited.

 In this way, dispersible silica nano particles that prevent aggregation of silica nano hollow particles, can be easily dispersed as fine aggregate particles in water or an aqueous coating material, and can be mixed in a larger amount as a solid content. It becomes a hollow particle.

  In the dispersible silica nano hollow particles according to the invention of claim 8, the modified silicone oil is a modified silicone oil into which a lipophilic organic group is introduced. Here, examples of the “lipophilic organic group” include a monoamine group, an amino group, and an alkyl group.

  By modifying the surface with a modified silicone oil introduced with a lipophilic organic group in this way, dispersible silica nano hollow particles can be aggregated only by stirring with a normal stirring device when dispersed in an organic solvent or solvent-based paint. Can be easily dispersed as fine agglomerated particles without mixing, and can be mixed in the state of being dispersed in fine agglomerated particles without agglomeration even when mixed in molten resin, and a larger amount Thus, the silica nano hollow particles can sufficiently exhibit the properties such as heat insulation and transparency.

 In this way, the silica nano hollow particles can be prevented from agglomerating and easily dispersed as fine agglomerated particles in an organic solvent, solvent-based paint, molten resin, etc., and a larger amount is mixed as a solid content. Dispersible silica nano hollow particles can be obtained.

 The method for producing a dispersion of silica nano-hollow particles according to the invention of claim 9 is a dispersion of nano-hollow particles composed of silica shells having an outer diameter in a range of approximately 30 nm to approximately 300 nm in a solvent. When the particle size distribution is measured by a dynamic light scattering method after being dispersed in a solvent, the entire frequency distribution (intensity distribution) falls within the range of 110 nm to 550 nm, and the frequency distribution (intensity distribution) ) Is present in the range of 200 nm to 350 nm, a step of adding an organic solvent and a surface modifier to nano hollow particles made of silica shell and dispersing it strongly with a wet jet mill, and a silica shell A step of surface modification by adding a surface modifier to the surface of the nano-hollow particles, and a process of mixing the nano-hollow particles composed of the surface-modified silica shell into a solvent and finely dispersing them again When, comprising adding an modified silicone oil in a solvent, and a step of ultrasonic dispersion by an ultrasonic disperser.

  Here, the “solvent” includes both water and an organic solvent, and the organic solvent includes aliphatic alcohols such as methanol, ethanol, and propanol, aliphatic hydrocarbons such as n-hexane, and aromatic carbonization such as xylene. Including hydrogen, etc. As the “organic solvent”, aliphatic alcohols such as methanol, ethanol and propanol, aliphatic hydrocarbons such as n-hexane, aromatic hydrocarbons such as xylene, and the like can be used.

 Furthermore, as the “surface modifier”, an isocyanate compound, an amine compound, a vinyl compound, an epoxy compound, a methacryloxy compound, an acrylic compound, an imide compound, a compound having an alkyl group, a compound having an aryl group, Etc. can be used. Further, as the “wet jet mill”, specifically, a nanomizer manufactured by SG Engineering Co., Ltd., an ultra-high pressure homogenizer LAB2000 manufactured by SMT Co., Ltd., an optimizer manufactured by Sugino Machine Co., Ltd., etc. Can be used.

 In the method for producing a dispersion according to the present invention, an organic solvent and a surface modifier are first added, and strong stirring and dispersion are performed by a wet jet mill to finely disperse most of the hollow nanoparticle made of silica shells. In this state, the surface is modified by reacting and adding a surface modifier to the hollow nanoparticle made of silica shell. By surface modification in this way, the dispersibility of the nano hollow particles made of silica shells is improved, and the nano hollow particles made of finely dispersed silica shells do not easily reaggregate.

 Therefore, the nano hollow particles made of the silica shell with the surface modification are mixed with the solvent and dispersed again to finely disperse most of the nano hollow particles made of the silica shell. And, as a result of earnest experimental research, the present inventors added silicone oil to the solvent and dispersed ultrasonically, so that the nano hollow particles composed of almost all silica shells were finely dispersed and dispersed in the solvent. When the particle size distribution is measured by the dynamic light scattering method, the entire frequency distribution (intensity distribution) falls within the range of 110 nm to 550 nm, and the peak of the particle size distribution due to the frequency distribution (intensity distribution) is 200 nm to 350 nm. The present invention has been completed based on this finding.

  In this way, the silica nano hollow particles can be prevented from agglomerating and easily dispersed as fine agglomerated particles in a solvent such as water or an organic solvent, and a larger amount can be mixed as a solid content. This is a method for producing a dispersion of nano hollow particles made of silica shell.

  In the method for producing a dispersion of silica nano hollow particles according to the invention of claim 10, the step of surface modification is performed by applying high temperature and high pressure to a mixture of nano hollow particles composed of silica shell, an organic solvent and a surface modifier. In this supercritical state, a surface modifier is reacted and added to the surface of the hollow nanoparticle made of silica shell.

  By setting the supercritical state of the organic solvent, the organic solvent freely enters the aggregated particles together with the surface modifier, and the surface modifier is reacted and added to the entire surface of the fine aggregated particles. For this reason, even if it performs powerful stirring and dispersion | distribution with a wet jet mill, each surface of the silica nano hollow particle which does not disperse | distribute to a fine aggregation particle but remains as a huge aggregation particle | grain can be surface-modified. Therefore, the operating conditions of the wet jet mill can be relaxed.

  In this way, the silica nano hollow particles can be prevented from agglomerating and easily dispersed as fine agglomerated particles in a solvent such as water or an organic solvent, and a larger amount can be mixed as a solid content. This is a method for producing a dispersion of nano hollow particles made of silica shell.

  In the method for producing a dispersion of nano-hollow particles comprising silica shells according to the invention of claim 11, in the step of surface modification, the mixture is brought to a supercritical state of an organic solvent by applying high temperature and high pressure to the mixture using an autoclave.

  To bring the organic solvent into the supercritical state and allow the organic solvent to freely enter the aggregated particles of the aggregated silica nano hollow particles together with the surface modifier, it is necessary to apply high temperature and high pressure to the mixture of the organic solvent and the surface modifier. However, by using an autoclave, high temperature and high pressure can be applied safely and freely, and a surface modifier can be reacted and added to the entire surface of the finely-agglomerated particles of silica nano hollow particles.

  In this way, the silica nano hollow particles can be prevented from agglomerating and easily dispersed as fine agglomerated particles in a solvent such as water or an organic solvent, and a larger amount can be mixed as a solid content. This is a method for producing a dispersion of nano hollow particles made of silica shell.

  Embodiments of the present invention will be described below with reference to the drawings. In the second and subsequent embodiments, the same symbols and the same reference numerals as those in the first embodiment mean the same or corresponding functional parts as those in the first embodiment, and the same symbols and the same in the embodiments. The reference numeral is a functional part common to those embodiments, and therefore detailed description thereof is omitted here.

Embodiment 1
First, a method for producing a dispersion of silica nano hollow particles according to Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic diagram showing a production process of silica nano hollow particles used in the method for producing a dispersion of silica nano hollow particles according to Embodiment 1 of the present invention. FIG. 2 is a flowchart showing a method for producing a dispersion of silica nano hollow particles according to Embodiment 1 of the present invention. FIG. 3 is a schematic diagram showing Example 1 of the surface modification method in the method for producing a dispersion of silica nano hollow particles according to Embodiment 1 of the present invention.

 FIG. 4 is a schematic diagram showing Example 2 of the surface modification method in the method for producing a dispersion of silica nano hollow particles according to Embodiment 1 of the present invention. FIG. 5 is a schematic diagram showing Example 3 of the surface modification method in the method for producing a dispersion of silica nano hollow particles according to Embodiment 1 of the present invention. FIG. 6 is a schematic diagram showing Example 4 of the surface modification method in the method for producing a dispersion of hollow silica nanoparticle according to Embodiment 1 of the present invention.

 Initially, the outline of the manufacturing method of the silica nano hollow particle which concerns on this invention is demonstrated with reference to FIG.

 As shown in FIG. 1, first, calcium carbonate fine particles 2 that become core particles are crystal-grown. The calcium carbonate crystal 2 produced here is calcite and is a hexagonal crystal system. However, by controlling the synthesis conditions, it is grown into a shape as if it is a cubic system, that is, a “cubic shape”. be able to. Here, the “cubic form” refers to a shape similar to a cube surrounded by a face, not limited to a cube. After crystal growth so that the outer diameter of the calcium carbonate 2 is 20 nm to 200 nm, the calcium carbonate fine particles 2 are coated with silica 3 using silicon alkoxide by a sol-gel method.

 Subsequently, this is dispersed in water, and an acid is added to dissolve and discharge the internal calcium carbonate 2, thereby forming nano hollow particles 4 composed of cubic shaped silica shells. Finally, nano hollow particles 1 made of a dense silica shell are produced by closing the pores from which calcium carbonate 2 dissolved by baking at 800 ° C. has flowed out. The hollow portion 1b of the nano hollow particle 1 made of silica shell has an inner diameter of 20 nm to 200 nm of the calcium carbonate fine particle 2 as a core particle, and the dense silica shell 1a has a thickness of 1 nm to 5 nm, even if it is thicker than 5 nm. Since it is around 20 nm, the outer diameter of the nano hollow particle 1 made of silica shell is approximately 30 nm to approximately 300 nm.

  Next, a method for producing a dispersion of nano hollow particles made of silica shells according to Embodiment 1 using the nano hollow particles 1 made of silica shells having a cubic shape will be described with reference to the flowchart of FIG. To do. In the first embodiment, nano hollow particles 1 made of a silica shell having a cubic shape with an average outer diameter of 70 nm and a porosity of about 70% to 80% having an outer diameter in the range of about 50 nm to 100 nm are used. I will do it.

 First, in step S10, the nano hollow particles 1 made of a silica shell having a cubic shape manufactured by the manufacturing process described with reference to FIG. 1 are added with n-hexane as an organic solvent and a surface modifier, and a high-speed stirrer. Stir and disperse with. In the first embodiment, as a “high-speed stirrer”, T.M. K. A fill mix is used. Here, the aggregated giant aggregated particles are dispersed to a particle diameter of about 5 μm. Next, the particles are strongly dispersed by a wet jet mill to form fine agglomerated particles having a particle size of approximately 0.5 μm or less (step S11). Here, as the “wet jet mill”, specifically, a nanomizer manufactured by SG Engineering Co., Ltd., an ultrahigh pressure homogenizer LAB2000 manufactured by SMT Co., Ltd., an optimizer manufactured by Sugino Machine Co., Ltd., Etc. can be used.

 Subsequently, the dispersion is applied to an evaporator to evaporate n-hexane as a solvent, thereby concentrating the concentration of nano hollow particles 1 made of silica shells from 1 wt% to 4 wt% (step S <b> 12). And the surface modification of the nano hollow particle 1 which consists of a silica shell is performed as a supercritical state of n-hexane by pressurizing and heating with an autoclave (step S13). The specific types of surface modifiers will be described later in detail.

 When the surface modification is completed, the nano hollow particles 1 composed of the surface-modified silica shell are pulverized, and are redispersed in a solvent (step S14), and again stirred and dispersed with a high-speed stirrer (step S15). Then, the modified silicone oil is added to this dispersion (step S16), and is ultrasonically dispersed with an ultrasonic disperser (step S17). And the high concentration dispersion 5 of the nano hollow particle 1 which consists of a silica shell can be obtained by performing classification and filtration (by the net | network which has a network of 25 micrometers) (step S18).

 By following the above steps, a high concentration of nano hollow particles 1 composed of silica shells, in which 20% by weight or more of nano hollow particles 1 composed of silica shells, which could conventionally be dispersed only up to 10% by weight, are dispersed. A dispersion 5 can be obtained. The reason for this is as follows.

That is, since the nano hollow particle 1 made of silica shell has a very large specific surface area of about 150 m ² / g, only a small percentage by weight can be mixed even if it is mixed with paint or molten resin. It was. This large specific surface area value is presumed to be due to the presence of fine molecular level irregularities on the surface of the nano hollow particles 1 made of silica shells. However, by modifying the surface, fine surface irregularities are filled with the surface modifier and the specific surface area is reduced. As a result, although it is mixed in the state of being dispersed in the fine aggregated particles, it is several μm to several tens A larger amount of silica nano hollow particles 1 can be mixed than in the case of mixing huge aggregated particles of the order of μm.

  Next, specific examples of surface modification in step S13 of FIG. 2 will be described with reference to FIGS.

  In Example 1 of this Embodiment 1 shown by FIG. 3, triethoxypropyl isocyanate silane (TEIS) 6 which is an isocyanate type compound is used as a surface modifier. In addition, the surface of the nano hollow particle 1 made of silica shell has an infinite number of hydroxyl groups (—OH), and in FIG. 3, only three of the innumerable hydroxyl groups are shown for easy understanding of the reaction. Yes.

  On the other hand, by reacting TEIS6 as a surface modifier for 1 hour at the critical temperature (234.9 ° C.) and critical pressure (3.02 MPa) of n-hexane in an autoclave using n-hexane as a solvent, Nano hollow particles 1 in which all three of the ethoxy groups of TEIS 6 are composed of silica shells are allowed to freely enter between nano hollow particles 1 composed of silica shells in which n-hexane is in a supercritical state and aggregated as giant aggregate particles. Then, it condenses with the hydroxyl groups on the surface and binds to the surface of the nano hollow particles 1 made of silica shell.

  Thus, the surface of the nano hollow particle 1 made of silica shell is covered with TEIS 6 as shown in FIG. 3 by the reaction of innumerable hydroxyl groups on the surface of the nano hollow particle 1 made of silica shell with TEIS 6. Thus, the surface modified particles 7 according to Example 1 of the first embodiment are formed. As a result, the nano hollow particles 1 composed of silica shells aggregated as giant aggregated particles on the order of several μm to several tens of μm are dispersed to form fine aggregated particles on the order of several hundreds of nm. Not only that, but the isocyanate group reacts with the active group of the organic resin to form a strong bond with the organic resin, whereby the surface-modified particles 7 that are more easily uniformly dispersed in the organic resin are obtained.

  Moreover, in Example 2 of this Embodiment 1 shown by FIG. 4, the 3-glycidoxy propyl triethoxysilane 11 which is an epoxy-type compound is used as a surface modifier. Numerous hydroxyl groups (—OH) are attached to the surface of the nano hollow particle 1 made of silica shell, and FIG. 4 shows only three of the innumerable hydroxyl groups so that the reaction can be easily understood.

  On the other hand, 3-glycidoxypropyltriethoxysilane 11 as a surface modifier is used in an autoclave with n-hexane as a solvent. The critical temperature (234.9 ° C.) and critical pressure (3.02 MPa) of n-hexane are used. ) For 1 hour, n-hexane enters a supercritical state, and freely enters between the nano hollow particles 1 made of silica shells aggregated as giant aggregated particles on the order of several μm to several tens of μm. All the three ethoxy groups of 3-glycidoxypropyltriethoxysilane 11 undergo a condensation reaction with the hydroxyl groups on the surface of the nano hollow particles 1 made of silica shells, and bind to the surfaces of the nano hollow particles 1 made of silica shells.

  In this way, by reacting innumerable hydroxyl groups on the surface of the nano hollow particle 1 made of silica shell and 3-glycidoxypropyltriethoxysilane 11, as shown in FIG. 4, nano hollow made of silica shell is made. The surface of the particle 1 is covered with 3-glycidoxypropyltriethoxysilane 11 to form the surface modified particle 12 according to Example 2 of the first embodiment. As a result, the nano hollow particles 1 composed of silica shells aggregated as giant aggregated particles on the order of several μm to several tens of μm are dispersed to form fine aggregated particles on the order of several hundreds of nm. In addition, the epoxy group reacts with the active group of the organic resin to form a strong bond with the organic resin, whereby the surface modified particles 12 that are more easily uniformly dispersed in the organic resin. The surface modified particles 12 are hydrophilic surface modified particles.

  Further, as shown in FIG. 5, in Example 3 of Embodiment 1, methyltriethoxysilane 15 is used as the surface modifier. Numerous hydroxyl groups (—OH) are attached to the surface of the nano hollow particle 1 made of silica shell, and in FIG. 5, only three of the innumerable hydroxyl groups are shown so that the reaction can be easily understood.

  In contrast, methyltriethoxysilane 15 as a surface modifier was reacted for 1 hour at the critical temperature (234.9 ° C.) and critical pressure (3.02 MPa) of n-hexane in an autoclave using n-hexane as a solvent. As a result, n-hexane enters a supercritical state, and freely enters between the nano hollow particles 1 made of silica shells aggregated as giant aggregated particles on the order of several μm to several tens of μm. All three of the ethoxy groups are condensed with hydroxyl groups on the surface of the nano hollow particle 1 made of silica shell, and bonded to the surface of the nano hollow particle 1 made of silica shell.

  In this way, by reacting innumerable hydroxyl groups on the surface of the nano hollow particle 1 made of silica shell and methyltriethoxysilane 15, the surface of the nano hollow particle 1 made of silica shell becomes as shown in FIG. 5. Covered with methyltriethoxysilane 15, surface modified particles 16 according to Example 3 of Embodiment 1 are formed. As a result, the nano hollow particles 1 composed of silica shells aggregated as giant aggregated particles on the order of several μm to several tens of μm are dispersed to form fine aggregated particles on the order of several hundreds of nm. In addition, the methyl group reacts with the active group of the organic resin to form a strong bond with the organic resin, whereby the surface modified particles 16 that are more easily uniformly dispersed in the organic resin. The surface modified particles 16 are lipophilic surface modified particles.

  Furthermore, as shown in FIG. 6, in Example 4 of the present Embodiment 1, acryloxypropyltrimethoxysilane 17 is used as a surface modifier. Numerous hydroxyl groups (—OH) are attached to the surface of the nano hollow particle 1 made of silica shell, and FIG. 6 shows only three of the innumerable hydroxyl groups so that the reaction can be easily understood.

  On the other hand, acryloxypropyltrimethoxysilane 17 as a surface modifier is 1 at the critical temperature (234.9 ° C.) and critical pressure (3.02 MPa) of n-hexane in an autoclave using n-hexane as a solvent. By reacting for a period of time, n-hexane becomes a supercritical state, and freely enters between the nano hollow particles 1 composed of silica shells aggregated as giant aggregated particles on the order of several μm to several tens of μm. All three of the methoxy groups of the trimethoxysilane 17 undergo a condensation reaction with the hydroxyl groups on the surface of the nano hollow particle 1 made of silica shell, and bind to the surface of the nano hollow particle 1 made of silica shell.

  In this way, by reacting innumerable hydroxyl groups on the surface of the nano hollow particle 1 made of silica shell and acryloxypropyltrimethoxysilane 17, as shown in FIG. 6, the nano hollow particle 1 made of silica shell 1 The surface is covered with acryloxypropyltrimethoxysilane 17 to form surface modified particles 18 according to Example 4 of the first embodiment.

 As a result, the nano hollow particles 1 composed of silica shells aggregated as giant aggregated particles on the order of several μm to several tens of μm are dispersed to form fine aggregated particles on the order of several hundreds of nm. In addition, the acryloxy group reacts with the active group of the organic resin to form a strong bond with the organic resin, whereby the surface modified particles 18 that are more easily uniformly dispersed in the organic resin are obtained. Further, since the acryloxy group is a UV functional group that reacts with ultraviolet rays (UV), by using the surface modified particles 18 according to Example 4 of the first embodiment, the surface modified particles 18 that are cured in response to the ultraviolet rays. It can be applied to various uses.

  As described above, the highly concentrated dispersion 5 of nano hollow particles 1 made of silica shell can be obtained by the method for producing a dispersion of nano hollow particles made of silica shell according to the first embodiment. In this high-concentration dispersion 5, the nano hollow particles 1 made of silica shell can be stably mixed by 20 wt% or more, so that the silica can be mixed with a paint or directly applied to a target object. Features such as heat insulation and transparency of the hollow nanoparticle 1 made of a shell can be utilized to the maximum.

  Thus, in the dispersion liquid of the nano hollow particles composed of the silica shell and the manufacturing method thereof according to Embodiment 1, the silica nano hollow particles are prevented from agglomerating, and a solvent such as water or an organic solvent, a molten resin, or the like. Can be easily dispersed as fine agglomerated particles, and a larger amount can be mixed as a solid content.

Embodiment 2
Next, dispersible silica nano hollow particles according to Embodiment 2 of the present invention, a method for producing the same, and application fields will be described with reference to FIGS.

 FIG. 7 is a flowchart showing a method for producing dispersible silica nano hollow particles according to Embodiment 2 of the present invention. FIG. 8 is a flowchart showing a method for producing dispersible silica nano hollow particles according to a modification of the second embodiment of the present invention. FIG. 9 is a graph showing the particle size distribution of the dispersible silica nano hollow particles according to Example 1 of Embodiment 2 of the present invention. FIG. 10 is a graph showing the particle size distribution of the dispersible silica nano hollow particles according to Example 2 of Embodiment 2 of the present invention. FIG. 11 is a graph showing the particle size distribution of the dispersible silica nano hollow particles according to Example 3 of Embodiment 2 of the present invention.

 FIG. 12 is a graph showing the particle size distribution of dispersible silica nanohollow particles according to Example 4 of Embodiment 2 of the present invention. FIG. 13 is a graph showing the particle size distribution of dispersible silica nanohollow particles according to Example 5 of Embodiment 2 of the present invention. FIG. 14 is a graph showing the particle size distribution of the dispersible silica nano hollow particles according to Example 6 of Embodiment 2 of the present invention. FIG. 15 is a graph showing the particle size distribution of dispersible silica nanohollow particles according to Example 7 of Embodiment 2 of the present invention. FIG. 16 is a graph showing the particle size distribution of the dispersible silica nano hollow particles according to Example 8 of Embodiment 2 of the present invention.

 FIG. 17 is a graph showing the particle size distribution of silica nano hollow particles according to a conventional example. FIG. 18A is a perspective view showing an example in which the dispersible silica nano hollow particles according to Embodiment 2 of the present invention are applied to a laminated glass of an automobile, and FIG. 18B is an enlarged cross-sectional view. FIG. 19A is a perspective view showing an example in which dispersible silica nano hollow particles according to Embodiment 2 of the present invention are applied to a laminated glass of a high-rise building, and FIG. 19B is an enlarged cross-sectional view.

 Also in the present second embodiment, the nano hollow particles 1 made of a silica shell having a cubic shape with an average outer diameter of 70 nm and an outer diameter in a range of about 50 nm to 100 nm and a porosity of about 70% to 80% are used. I will do it. In the method for producing dispersible silica nano-hollow particles according to the second embodiment, as shown in FIG. 7, first, nano-hollow particles comprising a cubic-shaped silica shell produced by the production process described in FIG. 1 is blended with ethanol as an organic solvent and a modified silicone oil as a surface modifier in a predetermined blending amount (step S30), and stirred and dispersed with a high-speed stirrer (step S31).

 Also in the second embodiment, as the “high-speed stirrer”, T.I. K. A fill mix is used. Here, the aggregated giant aggregated particles are dispersed to a particle diameter of about 5 μm. Next, after this dispersion is filtered through a sieve (step S32), it is strongly dispersed by a wet jet mill to form fine agglomerated particles having a particle diameter of approximately 0.5 μm (500 nm) or less (step S33). . Here, as the “wet jet mill”, specifically, a nanomizer manufactured by SG Engineering Co., Ltd., an ultrahigh pressure homogenizer LAB2000 manufactured by SMT Co., Ltd., an optimizer manufactured by Sugino Machine Co., Ltd., Etc. can be used.

 Subsequently, the dispersion is applied to an evaporator to evaporate the solvent, and the concentration of the nano hollow particles 1 made of silica shell is concentrated from 2.5% by weight to 10% by weight (step S34). Thereafter, the moisture content is set to 3% or less with a vibration dryer (step S35), and further, the powder dryer is heated at 125 ° C. for 60 minutes for drying (step S36). The dispersible silica nano hollow particles 20 according to the second embodiment are obtained through the above steps.

 Here, in the blending stage of step S30, hydrophilic dispersible silica nano hollow particles are obtained by using a modified silicone oil into which a hydrophilic organic group such as a polyether group, an ethoxy group, or a carboxyl group is introduced as the modified silicone oil. 20 Therefore, when it is dispersed in water or water-based paint, it can be easily dispersed as fine agglomerated particles without agglomeration only by stirring with a normal stirring device, and a larger amount can be mixed. Thus, the characteristics of the silica nano hollow particles 1 such as heat insulation and transparency can be sufficiently exhibited.

 In contrast, by using a modified silicone oil into which a lipophilic organic group such as a monoamine group, an amino group, or an alkyl group is introduced as the modified silicone oil, the lipophilic dispersible silica nano hollow particle 20 is obtained. Therefore, when it is dispersed in an organic solvent or solvent-based paint, it can be easily dispersed as fine agglomerated particles without agglomeration only by stirring with a normal agitator, and also when mixed into molten resin, etc. It can be mixed in the state of being dispersed in the fine aggregated particles without agglomeration, and can be mixed in a larger amount, so that the silica nano hollow particles 1 can fully exhibit the properties such as heat insulation and transparency. Can be made.

 Next, the manufacturing method of the dispersible silica nano hollow particle which concerns on the modification of this Embodiment 2 is demonstrated with reference to FIG. As shown in FIG. 8, first, nano hollow particles 1 made of a silica shell having a cubic shape manufactured by the manufacturing process described with reference to FIG. It mix | blends with triethoxypropyl isocyanate silane (TEIS) 6 as a modifier (step S40), and is stirred and disperse | distributed with a high-speed stirrer (step S41). Also in the modification of the second embodiment, the nano hollow particles composed of silica shells having a cubic shape with an average outer diameter of 70 nm and a porosity of approximately 70% to 80% having an outer diameter in the range of approximately 50 nm to 100 nm. 1 is used.

  Here, the aggregated giant aggregated particles are dispersed to a particle diameter of about 5 μm. Next, after this dispersion is filtered through a sieve (step S42), it is strongly dispersed by a wet jet mill to form fine agglomerated particles having a particle diameter of about 0.5 μm or less (step S43). Subsequently, the dispersion is applied to an evaporator to evaporate the solvent, and the concentration of the nano hollow particles 1 made of silica shell is concentrated from 2.5% by weight to 10% by weight (step S44).

 Then, by applying pressure and heating in an autoclave and reacting at a critical temperature (234.9 ° C.) / Critical pressure (3.02 MPa) of n-hexane for 1 hour, the surface modifier is converted into a supercritical state of n-hexane. The surface modification of the nano hollow particles 1 made of silica shell is performed by the TEIS 6 (step S45). As the types of surface modifiers, in addition to TEIS6, as in the first embodiment, hydrophilic surface modifiers, lipophilic surface modifiers, UV-reactive agents as shown in FIGS. 4 to 6 are used. A surface modifier, etc. can be used.

 As a result, the nano hollow particles 1 made of silica shell are surface-modified with TEIS 6 and pulverized to obtain the dispersible silica nano hollow particles 21 according to the modification of the second embodiment.

  The dispersibility of the dispersible silica nano hollow particles 20 and 21 according to Embodiment 2 thus obtained was evaluated by measuring the particle size distribution as compared with the conventional silica nano hollow particles. The particle size distribution was measured by the dynamic light scattering method among the laser diffraction / scattering methods, and a Zetasizer 3000HS manufactured by Malvern, England was used as the particle size distribution measuring device. The results are shown in FIGS.

  Here, the dispersible silica nano hollow particles 20 according to Examples 1 to 5 of the second embodiment shown in FIGS. 9 to 13 are modified silicone in the blending step of step S30 in the flowchart of FIG. 7 described above. It is a hydrophilic dispersible silica nano hollow particle produced by using a modified silicone oil in which a polyether group which is a hydrophilic organic group is introduced as an oil. The difference between the examples is the difference in the solvent when measuring the particle size distribution. Example 1 uses methyl ethyl ketone (MEK) as the solvent, and the concentration of the dispersible silica nano hollow particles (silica concentration) 2 Example 2 to Example 5 were measured at a silica concentration of 2.5% by weight using isopropyl alcohol (IPA) as a solvent.

 On the other hand, the dispersible silica nano hollow particles 20 according to Examples 6 to 8 of Embodiment 2 shown in FIGS. 14 to 16 are modified with a monoamine group that is a lipophilic organic group introduced as a modified silicone oil. Lipophilic dispersible silica nano hollow particles produced using silicone oil. The difference between the examples is the difference in the concentration of the dispersible silica nano-hollow particles (silica concentration) when measuring the particle size distribution, all using isopropyl alcohol (IPA) as the solvent, The measurement was performed at a silica concentration of 2.3% by weight, Example 7 was measured at a silica concentration of 2.5% by weight, and Example 8 was measured at a silica concentration of 2.4% by weight.

  As shown in FIG. 9 to FIG. 16, all of the dispersive silica nano hollow particles 20 according to Examples 1 to 8 of the second embodiment fall within the range of 110 nm to 550 nm. The peak of the particle size distribution due to the frequency distribution (intensity distribution) exists in the range of 200 nm to 350 nm. Among them, the particle size distributions of Examples 2 to 5 of the second embodiment shown in FIGS. 10 to 13 and Example 6 shown in FIG. 14 are extremely sharp and within a narrow particle size range. It can be seen that all the dispersible silica nano hollow particles 20 are distributed, the particle diameter is fine and the size is uniform.

 On the other hand, as shown in FIG. 17, the particle size distribution of the conventional silica nano hollow particles 1 is widened in the range of 300 nm to 700 nm, and the peak of the particle size distribution is as large as about 500 nm. . As a result, the dispersible silica nano hollow particles 20 according to the second embodiment are remarkably improved in dispersibility by performing treatment such as surface modification, and all particles are dispersed in fine aggregated particles of about 500 nm or less. It became clear that

  Thus, in the dispersible silica nano hollow particles 20 and 21 and the manufacturing method thereof according to the second embodiment, the silica nano hollow particles 1 are prevented from agglomerating, and a solvent such as water or an organic solvent, an organic paint or inorganic It can be easily dispersed as fine agglomerated particles in a paint such as a paint or a molten resin, and a larger amount can be mixed as a solid content.

  Application fields of the dispersible silica nano hollow particles 20 and 21 according to the second embodiment having such excellent dispersibility will be described with reference to FIGS. 18 and 19.

  As shown in FIG. 18, a laminated glass as a tempered glass is used in a window glass for an automobile 30, particularly in a windshield 31, in order to prevent scattering of glass fragments when a foreign object collides and breaks. It is obliged to do. As shown in the enlarged sectional view of FIG. 18 (b), this laminated glass 31 is laminated by sandwiching polyvinyl butyral (PVB) 33 as an adhesive between two glasses 32A and 32B. In addition to preventing the glass fragments from being scattered when broken, it is excellent in penetration resistance, so that it is possible to prevent the occupant from breaking through the windshield 31 in the event of an accident.

  However, the automobile 30 has a problem that the temperature inside the vehicle increases due to sunlight in the summer, and the conventional windshield has low transmittance of infrared rays, which are heat rays, but the outer surface of the windshield warmed by sunlight. As a result, a heat flow occurred inside and the temperature inside the automobile 30 was raised.

  Therefore, as shown in the enlarged cross-sectional view of FIG. 18B, an intermediate layer 34 in which a large amount of the dispersible silica nano hollow particles 20 according to the second embodiment is mixed in the polyvinyl butyral (PVB) 33 is formed on the windshield. By providing in (laminated glass) 31, the heat insulation of silica nano hollow particle 1 is exhibited, the heat flow from the outer surface of windshield 31 to the inside is cut off, and the temperature rise inside automobile 30 is significantly reduced. Can be expected.

  In addition, as shown in FIG. 19 (a), most of the wall surface facing the main street in the high-rise building 35 is made glass, but laminated glass as tempered glass is also used as the window glass 36. It is used. Also as such a window glass 36 for a high-rise building 35, as shown in FIG. 19B, a large amount of the dispersible silica nano hollow particles 20 according to the second embodiment is mixed in polyvinyl butyral (PVB) 33. By providing the intermediate layer 34 in the window glass (laminated glass) 36, the heat insulating property of the silica nano hollow particles 1 is exhibited, the heat flow from the outer surface to the inside of the window glass 36 is blocked, and the high-rise building 35 The effect of significantly reducing the temperature rise in the room can be expected.

  In addition, as an application field of the dispersible silica nano hollow particles 20 and 21 according to the second embodiment, a heat insulating paint obtained by dispersing the dispersible silica nano hollow particles 20 and 21 in the paint (particularly, the silica nano hollow particles 1). Transparent heat insulating paint for forming a transparent heat insulating coating film utilizing the transparency of the above), a heat insulating film formed by depositing metal on one side of a transparent synthetic resin film and uniformly applying the heat insulating paint on the other side, A heat insulating film obtained by mixing dispersible silica nano hollow particles 20 and 21 in a synthetic resin and processing the film into a film, or by mixing dispersible silica nano hollow particles 20 and 21 in a synthetic fiber material and spinning it. And the like.

  In each of the above-described embodiments, the hollow silica particles having a silica shell having an outer diameter in the range of about 50 nm to 100 nm and an average outer diameter of 70 nm and a porosity of about 70% to 80% are used. Although the case where the nano hollow particle 1 made of a shell is used has been described, any nano hollow particle made of a silica shell having an outer diameter of about 30 nm to about 300 nm may be used.

  In each of the above embodiments, only the case where ethanol or n-hexane is used as the organic solvent has been described. However, the present invention is not limited to this, and other organic solvents such as aliphatic alcohols such as methanol and propanol are used. Aromatic hydrocarbons such as xylene can be used.

  In practicing the present invention, the composition, components, shape, quantity, material, size, production method, etc. of other parts of the dispersible silica nanohollow particles are also produced. Other steps of the method are not limited to the above embodiments.

  In addition, since the numerical value quoted in the embodiment of the present invention does not indicate a critical value but indicates a preferable value suitable for implementation, even if the numerical value is slightly changed, the implementation is denied. is not.

FIG. 1 is a schematic diagram showing a production process of silica nano hollow particles used in the method for producing a dispersion of silica nano hollow particles according to Embodiment 1 of the present invention. FIG. 2 is a flowchart showing a method for producing a dispersion of silica nano hollow particles according to Embodiment 1 of the present invention. FIG. 3 is a schematic diagram showing Example 1 of the surface modification method in the method for producing a dispersion of silica nano hollow particles according to Embodiment 1 of the present invention. FIG. 4 is a schematic diagram showing Example 2 of the surface modification method in the method for producing a dispersion of silica nano hollow particles according to Embodiment 1 of the present invention. FIG. 5 is a schematic diagram showing Example 3 of the surface modification method in the method for producing a dispersion of silica nano hollow particles according to Embodiment 1 of the present invention. FIG. 6 is a schematic diagram showing Example 4 of the surface modification method in the method for producing a dispersion of hollow silica nanoparticle according to Embodiment 1 of the present invention. FIG. 7 is a flowchart showing a method for producing dispersible silica nano hollow particles according to Embodiment 2 of the present invention. FIG. 8 is a flowchart showing a method for producing dispersible silica nano hollow particles according to a modification of the second embodiment of the present invention. FIG. 9 is a graph showing the particle size distribution of the dispersible silica nano hollow particles according to Example 1 of Embodiment 2 of the present invention. FIG. 10 is a graph showing the particle size distribution of the dispersible silica nano hollow particles according to Example 2 of Embodiment 2 of the present invention. FIG. 11 is a graph showing the particle size distribution of the dispersible silica nano hollow particles according to Example 3 of Embodiment 2 of the present invention. FIG. 12 is a graph showing the particle size distribution of dispersible silica nanohollow particles according to Example 4 of Embodiment 2 of the present invention. FIG. 13 is a graph showing the particle size distribution of dispersible silica nanohollow particles according to Example 5 of Embodiment 2 of the present invention. FIG. 14 is a graph showing the particle size distribution of the dispersible silica nano hollow particles according to Example 6 of Embodiment 2 of the present invention. FIG. 15 is a graph showing the particle size distribution of dispersible silica nanohollow particles according to Example 7 of Embodiment 2 of the present invention. FIG. 16 is a graph showing the particle size distribution of the dispersible silica nano hollow particles according to Example 8 of Embodiment 2 of the present invention. FIG. 17 is a graph showing the particle size distribution of silica nano hollow particles according to a conventional example. FIG. 18A is a perspective view showing an example in which the dispersible silica nano hollow particles according to Embodiment 2 of the present invention are applied to a laminated glass of an automobile, and FIG. 18B is an enlarged cross-sectional view. FIG. 19A is a perspective view showing an example in which dispersible silica nano hollow particles according to Embodiment 2 of the present invention are applied to a laminated glass of a high-rise building, and FIG. 19B is an enlarged cross-sectional view.

Explanation of symbols

1 Nano hollow particles made of silica shell 2 Core particles (calcium carbonate)
3 Silica coating 5 High concentration dispersion of nano hollow particles made of silica shell 6, 11, 15, 17 Surface modifier 7, 12, 16, 18 Surface modified particles 20, 21 Dispersible silica nano hollow particles 31, 36 Laminated glass

Claims (11)

Dispersible silica nano-hollow particles in which nano-hollow particles composed of a silica shell having an outer diameter in a range of about 30 nm to about 300 nm can be easily finely dispersed in a solvent,
An organic solvent and a surface modifier are added to the nano hollow particles composed of the silica shell and dispersed strongly by a wet jet mill, and the surface modifier is reacted and added to the nano hollow particles composed of the silica shell. Dispersible silica nano-hollow particles, wherein the nano-hollow particles comprising the silica shell are finely dispersed and powdered.   When the particle size distribution is measured by the dynamic light scattering method after being dispersed in the solvent, all of the frequency distribution (intensity distribution) falls within the range of 110 nm to 550 nm, and the particles according to the frequency distribution (intensity distribution) The dispersible silica nanohollow particle according to claim 1, wherein a peak of a diameter distribution exists in a range of 200 nm to 350 nm.   The surface modification is performed by applying high temperature and high pressure to a mixture of nano hollow particles composed of silica shells strongly dispersed by the wet jet mill, the organic solvent, and the surface modifier to form a supercritical state of the organic solvent. The dispersible silica nanohollow particle according to claim 1 or 2, wherein the surface modifier is reacted and added to the surface of the nanohollow particle composed of a shell.   The dispersible silica nano hollow particles according to claim 3, wherein the mixture is brought into a supercritical state of the organic solvent by applying high temperature and high pressure to the mixture using an autoclave.   The dispersible silica nano hollow particles according to any one of claims 1 to 4, wherein the surface modifier is an isocyanate compound.   The surface modifier is a modified silicone oil, and the surface modification strongly disperses the nano hollow particles made of the silica shell by the wet jet mill, and the surface modifier is surface of the nano hollow particles made of the silica shell. The dispersible silica nano hollow particles according to claim 2, wherein the dispersible silica nano hollow particles are reacted and added.   The dispersible silica nano hollow particles according to claim 6, wherein the modified silicone oil is a modified silicone oil into which a hydrophilic organic group is introduced.   The dispersible silica nano hollow particles according to claim 6, wherein the modified silicone oil is a modified silicone oil into which a lipophilic organic group is introduced. A method for producing a dispersion in which nano hollow particles composed of silica shells having an outer diameter in a range of approximately 30 nm to approximately 300 nm are dispersed substantially uniformly in a solvent,
When the particle size distribution is measured by the dynamic light scattering method after being dispersed in the solvent, all of the frequency distribution (intensity distribution) falls within the range of 110 nm to 550 nm, and the particles according to the frequency distribution (intensity distribution) The peak of the diameter distribution is in the range of 200 nm to 350 nm,
A step of adding an organic solvent and a surface modifier to the nano-hollow particles made of the silica shell and strongly dispersing in a wet jet mill;
A step of surface-modifying the surface of the nano-hollow particles composed of the silica shell by reactive addition of the surface modifier;
A step of mixing nano hollow particles composed of the surface-modified silica shell with the solvent and finely dispersing again;
Adding a modified silicone oil to the solvent;
And a process for producing a dispersion of silica nano hollow particles, the method comprising ultrasonically dispersing with an ultrasonic disperser.   The step of surface modification is performed by applying high temperature and high pressure to a mixture of the nano hollow particles composed of the silica shell, the organic solvent, and the surface modifier to form a super hollow state of the organic solvent. The method for producing a dispersion liquid of silica nano hollow particles according to claim 9, wherein the surface modifier is reacted and added to the surface of the silica nano hollow particles.   The method for producing a dispersion of silica nano hollow particles according to claim 10, wherein in the surface modification step, the mixture is brought into a supercritical state of the organic solvent by applying high temperature and high pressure to the mixture using an autoclave.

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