WO2009060989A1

WO2009060989A1 - Foliate material, method for production of the foliate material, and electrical/electronic component comprising the foliate material

Info

Publication number: WO2009060989A1
Application number: PCT/JP2008/070624
Authority: WO
Inventors: Shinji Naruse
Original assignee: Dupont Teijin Advanced Papers, Ltd.
Priority date: 2007-11-08
Filing date: 2008-11-06
Publication date: 2009-05-14
Also published as: TW200937467A

Abstract

Disclosed is a foliate material which comprises a meta-aramide short fiber and an inorganic flaky particle, which is suitable as a separator between electrically conducive members in an electrical/electronic component, which has satisfactory levels of resistance and strength, and which has excellent heat resistance.

Description

Specification

Thin leaf material, its manufacturing method and electrical / electronic parts using it

The present invention relates to a thin leaf material useful for isolating conductive members in an electrical 'electronic component and allowing ionic species such as electrolytes and ions to pass through, a manufacturing method thereof, and an electrical' electronic component using the same. The present invention relates to a thin-leaf material useful as a separator between electrodes of batteries, capacitors and the like using lithium ions, sodium ions, ammonium ions, hydrogen ions, etc. as a current carrier. Background art

As symbolized by recent advances in mobile communication devices and high-speed information processing devices, there are remarkable features in reducing the size and weight of electronic devices and improving their performance. In particular, expectations are high for compact, lightweight, high-capacity, high-performance batteries and capacitors that can withstand long-term storage, and a wide range of applications are being made, and component development is progressing rapidly. To meet this demand, there is an increasing need for technical and quality development of members, such as separators, which are partition materials between electrodes. Among the various characteristics required for separators, the following three characteristic items are recognized as particularly important.

(1) Good conductivity with electrolyte retained.

(2) High interelectrode shielding.

(3) Have mechanical strength.

Conventionally, a porous sheet formed using a polyolefin polymer such as polyethylene or polypropylene (see JP-A-6 3-2 7 3 6 5 1), a polyolefin polymer fiber such as polyethylene or polypropylene Non-woven fabric made into a sheet by using a non-woven fabric (refer to Japanese Patent Laid-Open No. 2 0 0 1-1 1 76 1), Non-woven fabric made into a sheet using Nai-Kon fiber Etc.) are widely used as separators. Such a separator is used in a battery as a single layer, or a plurality of layers stacked or rolled. These porous sheets and non-woven fabrics have good physical properties as separators. However, they are not always sufficient for the high capacity and high output required for batteries and capacitors for electric vehicles in recent years. Not done.

For separators in electrical and electronic parts such as batteries and capacitors that require high capacity and high output,

(1) Good conductivity with electrolyte retained (low resistance).

(2) High interelectrode shielding.

(3) Have mechanical strength.

(4) Chemical and electrochemical stability (heat resistance).

It is necessary to satisfy these four characteristics simultaneously.

In particular, conductivity and heat resistance are extremely high in terms of efficiently storing regenerative energy of brakes in electric and electronic parts such as batteries and capacitors that use large currents, for example, as driving power for electric vehicles. It is considered important. As a means for improving the heat resistance of the separator, a separator using a heat resistant material comprising an inorganic binder such as silica particles and glass fibers (JP-A-2 004-20726 1, JP-A-2004- No. 349586 and Japanese Patent Application Laid-Open No. 20 0 7-8 1 035) have been proposed, but both contain glass fibers that are inherently fragile. It is easy to break down, its mechanical properties deteriorate, and it is difficult to maintain its shape as a separator or to handle it in the manufacturing process. In order to fix inorganic binder to the separator, acrylic resin, cationic fixing reinforcing agent, It is necessary to add components such as a polymer flocculant, and there are problems such as a decrease in electrochemical stability such as a decrease in withstand voltage due to these agents remaining in the separator. Disclosure of the invention

An object of the present invention is to develop a low-resistance and high-heat-resistant separator material that can withstand a large current due to high capacity and high output. As a result of diligent investigations, the present inventors have found that the above object can be achieved by combining the meta-type aramide short fibers with the inorganic scaly particles, thereby completing the present invention. It came.

Accordingly, the present invention provides a thin-leaf material comprising at least one selected from a meta-type aramid short fiber, inorganic scaly particles, and optionally aramid fiber and a fibrillated aramid. is there.

The present invention also includes adding inorganic scaly particles by a fluid spray method while forming a meta-type aramide short fiber into a sheet by a wet papermaking method, and placing the resulting sheet between a pair of metal tools to form a meta-type. The present invention provides a method for producing the above-mentioned thin leaf material, characterized by high-temperature hot pressing at a temperature higher than the glass transition temperature of aramid.

Furthermore, the present invention further includes mixing a meta-type aramid short fiber and at least one selected from aramid fibrids and a fibrillated aramid in water, and forming an inorganic material by a fluid spray method while forming a sheet by a wet papermaking method. After the scaly particles are added, the sheet obtained is subjected to high-temperature hot pressing at a temperature equal to or higher than the glass transition temperature of the meta-type aramid between a pair of metal rolls. Is.

The present invention further provides an electrical / electronic component, particularly a battery or a capacitor, using the thin leaf material as a separator between conductive members.

Hereinafter, the present invention will be described in more detail. BEST MODE FOR CARRYING OUT THE INVENTION

Meta-type aramid:

In the present specification, the meta type aramid means a linear polymer compound in which 60% or more of the amide bonds are directly bonded to the meta position of the aromatic ring. Examples of such a meta-type amide include polymetaphenylene isophthalamide and a copolymer thereof. These meta-type amides are manufactured industrially by polycondensation of, for example, isophthalic acid salt, meta-diphenylamine by interfacial polymerization method, solution polymerization method, etc. The power that can be It is not limited to this. Among these meta-type aramids, polymetaphenylene isophthalamide is particularly suitable in that it has good molding processability, thermal adhesiveness, flame retardancy, heat resistance and the like. Meta type aramid short fiber:

The meta-type aramid short fiber used in the present invention is obtained by cutting a fiber made from a meta-type aramid. As such a fiber, for example, Teijin

Examples include “Tijin Conex (registered trademark)” by Co., Ltd. and “Nomex (registered trademark)” by DuPont, but are not limited to these. is not.

Meta-type aramide short fibers can generally have a fineness in the range of 0.05 to less than 25 dtex, in particular 0.05 to 5 dtex, more particularly 0.05 to 3 dtex. Here, fineness is defined as the fiber weight (g) per 1000 m. Fibers with a fineness of less than 0.05 dtex are prone to agglomeration in the wet process (described later), and fibers with a diameter of 25 dte _X or more are too large in diameter. If the density is 1.4 g / cm ³ , the diameter will be 45 microns or more, and inconveniences such as a decrease in aspect ratio, reduction of mechanical reinforcement effect, and poor uniformity of thin leaf material are likely to occur. Here, the poor uniformity of the thin leaf material means that the distribution of the void size is widened and the above-mentioned ionic species mobility is uneven.

Meta-type aramide short fibers can generally have a length in the range from 1 mm to less than 50 mm, in particular from 1 to 20 mm, more particularly from 1 to 10 mm. If the length of the short fiber is smaller than lmm, the mechanical properties of the thin leaf material will deteriorate, while those with a length of 50 mm or more will cause entanglement, binding J, etc. in the production of the thin leaf material by the wet method described later. It tends to occur and cause defects. Examples of the inorganic scaly particles used in combination with the above-mentioned meta-type aramid short fibers in the present invention include scaly silica and scaly titanate, but are not limited thereto. These inorganic scaly particles are usually 0.1-2 5 11 111, especially since they do not cause an increase in internal resistance without causing electrolyte impregnation and a decrease in permeation while binding fibers as a binder. It is preferable to have an average particle diameter in the range of 0.1 to 15 / m, and more particularly 0.1 to 10 m, but is not limited thereto. Examples of such inorganic scaly particles can be obtained under trade names such as “Sun Lovely (registered trademark)” by AGC S-Tech Co., Ltd. and “Terrases” by Otsuka Chemical Co., Ltd. 1S is not limited to these. Aramid Lipid:

Aramid fibres are film-like aramid particles that have paper-making properties, and are also called aramid pulp (see Japanese Patent Publication No. 35-1818 1). Like normal wood pulp, aramid fibrids can be used as a papermaking raw material after being subjected to disaggregation and beating, and so-called beating can be performed for the purpose of maintaining quality suitable for papermaking. This beating process can be performed by a disc refiner, a bitter, or other papermaking raw material processing equipment that exerts a mechanical cutting action. In this operation, the change in the form of fibrids can be monitored by the freeness test method specified in Japanese Industrial Standard P 8 1 2 1. In the present invention, the aramid fibrid after beating is generally 10 to 300 cm ³ , particularly 10 to 200 cm ³ , more particularly 10 to 100 cm. It is preferable to have a freeness within the range of ³ (Canadian Freeness). For fidels with a freeness greater than 300 cm ³ , the strength of the aramid leaf material formed from it may decrease, whereas when trying to obtain a freeness less than 10 cm ³ , The utilization efficiency of the mechanical power to be input is reduced, the amount of processing per unit time is often reduced, and the fineness of the fibres is excessively advanced, so that the so-called binder function is liable to be lowered. Shi Therefore, even if trying to obtain a freeness smaller than 10 cm ³ in this way, no particular advantage is recognized.

For the use of the present invention, it is preferred that the ramid fibrid has a weight average fiber length of 1 mm or less as measured with an optical fiber length measuring device after beating. Here, as the optical fiber length measuring device, measuring equipment such as Fiber Quality Analyzer (manufactured by Op Test Equipment), canny-type measuring device (manufactured by Kanny) can be used. In such an instrument, the fiber length and morphology of the aramid fiber passing through a certain optical path are individually observed, and the measured fiber length is statistically processed. If the weight average fiber length exceeds 1 mm, the electrolyte absorbability decreases, partial electrolyte impregnation occurs, and the internal resistance of electrical / electronic components increases. Fibrilized aramid:

Fibrilized aramids are fibrillated by applying shear force to aramid fibers, aramid fibers, etc., and their freeness is generally 10-800 cm ³ , especially 10 It is preferably in the range of ˜500 cm ³ , more particularly 10 to 200 cm ³ (Canadian freeness). Fibrilized aramids with a freeness greater than this range may not ensure adequate shielding between the electrodes, while attempting to obtain a freeness less than 10 cm ^3. Since the refinement of the fibrillated aramid proceeds too much, the so-called binder function tends to be lowered. Therefore, even if trying to obtain a freeness smaller than 10 cm ³ in this way, no significant advantage is recognized.

The fibrillated aramid usually has a specific surface area in the range of usually 5 gZm ² or more, in particular 7.5 to 1 50, more particularly 10 to 100 gZm ² . If the specific surface area of the fibrillated aramid is less than 5 gZm ^2, it is likely to cause a decrease in the pinder function. In addition, fibrillated alarms are usually greater than or equal to 0.0 lmm and less than 7 mm, especially 0.1 to 5 mm, more particularly 0. It is preferred to have a weight average fiber length in the range of 5 to 3 mm. A fibrillated aramid with a weight-average fiber length greater than this range will have poor dispersibility during papermaking and may cause local defects such as fiber masses. However, if an attempt is made to obtain a small weight average fiber length, the so-called binder function is likely to be lowered because the refinement of the fibrillated fiberamide proceeds excessively.

Specific examples of fibrillated aramids include those that can be obtained under trade names such as DuPont's “Keplar Pulp” and Teijin Twaron's “Twaron Pulp”, but are not limited thereto. It is not something. Thin leaf material:

The thin leaf material of the present invention is a sheet-like material mainly composed of at least one selected from the above-mentioned meta-type aramid short fibers and inorganic scaly particles, or these two components, and further aramid fibrids and fibrillated aramids. It can have any meta-type amide short fiber content, inorganic scaly particle content, aramid fiber content, fibrillated aramid content, basis weight and density (basis weight Z thickness). However, in the thin leaf material of the present invention, it is preferable that the meta type aramid short fibers having high heat resistance are the main components, and the inorganic scaly particles, the aramid fibrids, and the fibrillated aramids are a small component, in particular, When high-temperature hot pressing is performed between a pair of metal rolls, which will be described later, at a temperature equal to or higher than the glass transition temperature of the meta-type aramid, the lower the density of the meta-type aramid short fiber, the lower the density of the thin leaf material. It is possible and the tendency to lower the internal resistance value, the content of meta-type aramide short fibers is generally 80% (weight ratio) or more, especially 8 3 to 9 7% (weight ratio), more particularly 8 It is within the range of 5 to 9 5% (weight ratio), and the sum of non-scaled particles, aramid fibrids, and filipilized aramid is generally 20% (weight ratio) or less, especially 0 to 15% (Weight ratio) Furthermore it is particularly preferably from 0 in the range of 1 0% (by weight). When inorganic scale-like particles are used in combination with aramid fibrids and fibrillated aramids, the weight ratio of the former and the latter is generally 1 OZ1 ~: 1/10, especially 7.5Zl ~ lZ7. .5, more particularly within the range of 5Z1 to: 1 to 5.

Further, the thin leaf material generally has a thickness in the range of 5 to: L 000 μπι, particularly 7.5 to 600 μηι, and more particularly 10 to 200 μπι. If the thickness is smaller than 5 μπι, the mechanical properties will deteriorate, and it will be easy to cause problems in maintaining the form as a separator and handling in the manufacturing process. On the other hand, if it exceeds Ι Ο Ο Ο μΐη, It tends to increase, making it difficult to manufacture small, high-performance electric / electronic components.

Furthermore, the thin leaf material can generally have a basis weight in the range of 5 to 1000 g / m ² , especially 5 to 100 g / m ² , and more particularly 5 to 50 g / m ² . If the basis weight is 5 but less than I m ² , mechanical strength will be insufficient, causing various handling in the parts manufacturing process such as electrolyte impregnation and winding, and on the other hand, greater than 1 000 g / m ² Thin-leaf materials with a grammage tend to increase in thickness, impregnate electrolyte, and decrease in penetration.

The density of the thin leaf material is a value calculated from the basis weight / thickness, and usually takes a value within the range of 0.1 to 1.2 g / m ³ , especially 0.2 to 1.0 g / m ³ . Can do.

The thin leaf material of the present invention preferably further has a value represented by an internal resistance value (μπι) Ζ basis weight (gZm ² ) of 9 or less, particularly 6 to 7. Here, the internal resistance value is a value expressed by the following equation (1).

(Internal resistance value) = (Electric conductivity of electrical angle early solution) Z (Electric conductivity when electrolyte is injected into separator) X (Separator thickness) Formula (1) In the above formula (1), ( The electrical conductivity when the electrolyte is injected into the separator is the electrical conductivity calculated from the AC impedance measured between the two electrodes with the electrolyte injected into the separator. AC impedance measurement The constant frequency is not particularly limited, but generally 1 kHz to 100 kHz is preferred. Here, the electrolytic solution means a liquid in which an electrolyte is dissolved in a solvent.

There are no particular restrictions on the solvent, electrolyte, electrolyte concentration, etc. used in the above electrolyte solution. Examples of the solvent include ethylene carbonate, propylene carbonate, dimethinorecarbonate, jetinorecarbonate etinoremethinorecarbonate. , Butylene carbonate, gnoretaronitrile, adiponitrile, acetonitonyl, methoxyacetonitrile, 3-methoxypropionitrile, γ-butyrolacton, 0— / reloralatone, snorephoran, 3-methinoleszoreforane, nitroethane, Etromethane, trimethyl phosphate, Ν-methyloxazolidinone, Ν, Ν-dimethylformamide, Ν-methylpyrrolidone, dimethyl sulfoxide, Ν,

N′—Cymethylimidazolidinone, amidine, water and mixtures thereof.

Examples of the electrolyte include ionic substances, particularly combinations of the following cations and anions.

(1) Cations: Quaternary ammonium ions, quaternary phosphonium ions, lithium ions, sodium ions, ammonium ions, hydrogen ions and their mixtures.

(2) A-on: Perchlorate ion, borofluoride ion, hexafluorophosphate ion, sulfate ion, hydroxide ion and their mixtures.

It should be noted that a thin leaf material having an internal resistance value m) / basis weight (g / m ² ) exceeding 9 may cause a problem in that the output of electric / electronic parts is hindered. . Thin leaf material manufacturing method:

The thin leaf material of the present invention having the characteristics as described above generally has the above-mentioned meta-type amide polyamide short fibers and inorganic flaky particles, or meth-type amide amide short fibers, inorganic flaky particles, aramid fiber, and fibrillation. It can be produced by a method of forming a sheet after mixing at least one selected from the prepared aramids. Specifically, for example, at least one selected from the above-mentioned meta-type aramid short fibers and inorganic scaly particles, or the meta-type aramid short fibers, inorganic scaly particles, aramid fibrids and fibrylated aramids. A method of forming a sheet using air flow after dry blending; meta-type aramide short fibers and inorganic scaly particles, or meta-type aramide short fibers and inorganic scaly particles, aramid fibrids and fibrils. It is possible to apply a method in which at least one selected from aramids is dispersed and mixed in a liquid medium, then discharged onto a liquid-permeable support, for example, a net or a belt to form a sheet, and the liquid is removed and dried. Among these, a so-called wet papermaking method using water as a medium is preferably selected. In the wet papermaking method, at least one kind selected from at least meta-type aramide short fibers and inorganic scale-like particles, or meta-type amide short fibers, inorganic scale-like particles, aramid fibrids and filled primamides. In general, a single or mixed aqueous slurry containing is fed to a paper machine and dispersed, followed by dehydration, squeezing and drying, and then winding the sheet as a sheet. As the paper machine, for example, a long paper machine, a circular paper machine, an inclined paper machine, or a combination paper machine combining these can be used. In the case of production with a combination paper machine, a composite sheet composed of a plurality of paper layers can be obtained by forming and combining slurry having different mixing ratios.

The inorganic scaly particles are preferably added during the formation of a sheet by a wet papermaking method by a fluid spray method in order to fix the thin leaf material.

In recent years, a spray method has been proposed as a new coating method for paper and paperboard (see US Pat. No. 6,063,434). Spray nozzles include one-fluid nozzles called airless spray systems and two-fluid nozzles called air sprays. In the one-fluid spray, paint is pressurized and sprayed at a high speed from an elliptical spray nozzle. Fine paint grains are formed by the shear stress generated when the paint film comes into contact with the atmosphere, and the paint is applied to the substrate. This is a method of generating a coating film. The two-fluid spray has nozzles for air and paint at the tip of the nozzle. The high-pressure air flow is applied to the paint that has been sprayed at low pressure, and the paint is refined by the impact. This is a method of controlling the shape of the coated film with the air flow. In these spray coating methods, since there is no nip portion during coating, there is no coating defect caused by contact between the coating surface and the coating device, and inorganic scaly particles are used as a thin leaf material. It is not necessary to add components such as acrylic resin, cationic fixing reinforcing agent, and polymer flocculant for fixing, and electrochemical properties such as reduction in withstand voltage due to these agents remaining in the separator. There is no problem that the stability of the product is lowered. In addition to the above components, other fibrous components (for example, polyphenylene sulfide fibers, polyether ether ketone fibers, cellulosic fibers, PVA fibers, polyester fibers, arylate fibers, liquid crystal polyester fibers, polyethylene antennas) Organic fibers such as phthalate fibers; inorganic fibers such as glass fibers, mouth-wool wool, aspest, and boston fibers) can also be added. When these other fibrous components are added, the blending amount is desirably 50% or less, particularly 40% or less, based on the total weight of all the fiber components.

Thus, the sheet | seat obtained in this way can improve mechanical strength by hot-pressing between high temperature high pressure between a pair of flat plates or metal rolls. The conditions of the hot pressure are, for example, when using a metal roll, a temperature of 50 to 4 0 0 ¾, especially 3 00 to 3 70 ° C and a linear pressure of 5 0 to 2 0 00 kg / cm, especially A range of 70 to 500 kg / cm 2 can be exemplified, but it is particularly preferable to perform high-temperature hot pressing at a temperature equal to or higher than the glass transition temperature of the meta-type amide between a pair of metal rolls. High-temperature hot pressing above the glass transition temperature of metal aramid improves mechanical strength during hot pressing between metal rolls, and after thinning, the thin leaf is released from between metal rolls. Residual heat existing in the material causes stress to return to the original thickness, and the thickness increases, so that a thin leaf material with a high porosity and a low internal resistance can be produced.

It is also possible to simply press at room temperature without adding a heating operation. A plurality of thin leaf materials can be laminated during the hot pressing. The above hot pressing can be performed several times in any order. In order to further increase the strength of the thin leaf material of the present invention, it is used in a state of being laminated by another known separate → (for example, a polyolefin microporous membrane) and a known method (for example, the above-mentioned hot pressing process). You can also.

The thin leaf material of the present invention includes (1) excellent properties such as heat resistance and flame retardancy, and (2) contains meta-type aramid short fibers that are difficult to heat-melt. Since high porosity is maintained, ionic species mobility between electrodes is not impaired, (3) Excellent retention of electrolyte derived from void structure, (4) Specific gravity of meta-type polyamide is 1 It has characteristics such as being as small as 4 and lightweight, and can be preferably used as a separator between conductive members of electrical and electronic parts.

Production of electrical / electronic components such as batteries and capacitors using the thin leaf material of the present invention as a separator between conductive members can be performed by a method known per se.

Thus, electrical and electronic parts such as batteries and capacitors manufactured using the aramid thin leaf material of the present invention as a separator between conductive members are excellent in shielding between electrodes and maintain safety, and have a high void structure. And its inherently high heat resistance makes it able to withstand use in high current environments such as electric vehicles. Example

Hereinafter, the present invention will be described more specifically with reference to examples. These examples are merely examples, and are not intended to limit the contents of the present invention.

(Measuring method)

(1) Measurement of sheet basis weight and thickness

It carried out according to JISC 2 1 1 1.

(2) Measurement of tensile strength

A Tensilon tensile tester was carried out at a width of 15 mm, a chuck interval of 20 mm, and a tensile speed of 50 mm / min.

(3) Measurement of internal resistance The measurement temperature was 25 ° C., and 1M borosulfite and ethylene carbonate nopropylene carbonate (1/1 weight ratio) were used as the electrolyte. Reference example

(Raw material preparation)

Meta-type aramid short fiber (polymetaphenylene isophthalamide short fiber) (“Nomettas” (registered trademark)) manufactured by DuPont was cut into a length of 6 mm and used as a raw material for papermaking. The glass transition temperature of this meta-type aramid fiber is 275 ° C.

Polyphenylene phenylene isophthalamide was prepared by a method using a wet precipitator described in Japanese Patent Publication No. 35-1 1 85 1. This was processed with a breaker and a beater.

As a fibrillated aramid, “Twaron (registered trademark) 1094” of Teijin Twaron Co., Ltd. was processed with a disaggregator and a beater.

As inorganic scale-like particles, “Sun Lovely (registered trademark) LF SHN-50” by AGC S-Tech Co., Ltd. (average particle size 0.5 μη was diluted with ION-exchanged water to a solid content concentration of 1%. Examples 1 to 3 were used as spray solutions.

(Manufacture of thin leaf materials)

The prepared meta-type aramid short fibers and aramid fibrids or fibrillated aramids were mixed at the blending ratios of each example shown in Table 1, and dispersed in water to prepare a slurry. This slurry was applied to a tappy type hand machine (cross-sectional area: 325 cm ² ) to produce a sheet. Next, the diluted spray solution was introduced into a two-fluid sprayer (nozzle diameter: 1 mm) so as to achieve the blending ratio of each example shown in Table 1, and after mixing gas and liquid, the pressure was 0.3 kgf. After spraying on the sheet at / cm ² , it was dried for 30 minutes at a temperature of 100 ° C. Next, this was hot-pressed under the conditions shown in Table 1 with a metal-powered lender tool to obtain a thin leaf material. Table 1 shows the main characteristic values of the thin leaf material thus obtained. table 1

As a result, the electric conductivity of the electrolyte was 4.6 (m S / cm). Example:! The thin leaf materials of ~ 3 are considered to have low internal resistance and sufficient ionic species permeability, and in particular, the thin leaf material of Example 1 with low internal resistance / basis weight has greatly reduced internal resistance. It is useful as a separator between conductive members in electric and electronic parts such as batteries and capacitors in electric vehicles that require a large current. Comparative Example 1 and 2

(Manufacture of thin leaf material) The prepared meta-type aramid short fibers were mixed with aramid fiber in the mixing ratios for each comparative example shown in Table 2, and dispersed in water to prepare a slurry. A sheet-like material was produced from this slurry by a wet papermaking method. Next, this was hot-pressed under the conditions shown in Table 2 with a metal-powered render roll to obtain a thin leaf material.

Table 2 shows the main characteristic values of the thin leaf material thus obtained. Table 2

However, the electrical conductivity of the electrolytic solution was 4.6 (m S / cm).

As shown in Table 2, the thin leaf material of Comparative Example 1 has low internal resistance, but low tensile strength and insufficient mechanical strength, so various handling in the parts manufacturing process such as electrolyte impregnation treatment It tends to cause breakage.

In addition, the thin leaf material of Comparative Example 2 increased the content of the fiber bridge that improves the mechanical strength as a binder, so the tensile strength value was high, but the fibrid hinders the permeability of ionic species. Resistance became high. Such a thin-leaf material is considered not useful as a separator between conductive members in electric and electronic parts such as electric vehicle batteries and capacitors, which require a large current. The invention's effect

The thin leaf material of the present invention is considered to have sufficiently low internal resistance, sufficient ionic species permeability, high shielding between electrodes, and sufficient mechanical strength. It can be used as a separator between conductive members inside. In addition, electric and electronic parts such as batteries and capacitors that use this thin leaf material contain essentially heat-resistant meta-type aramide and inorganic scaly particles. Can be used.

Claims

The scope of the claims

1. A thin-leaf material comprising meta-type aramid short fibers and inorganic scaly particles.

2. The thin leaf material according to claim 1, further comprising at least one selected from aramid fibrids and fibrilized aramids.

3. The thin leaf material according to claim 1, wherein the content of the meta-type aramid short fibers is 80% by weight or more.

4. The thin leaf material according to claim 2, wherein the weight ratio of the inorganic scaly particles to the aramid fibrid and Z or fibrillated aramid is in the range of 10 to 1 to 1/10.

5. The value expressed by the internal resistance value (μ πι) / basis weight (g / m ² ) is 9 or less, where the internal resistance value is

(Internal resistance value) = (Electric conductivity of electrolyte) / (Electric conductivity when electrolyte is injected into separator) X (Separator thickness) In formula, (Electric conductivity when electrolyte is injected into separator) Degree) indicates the electrical conductivity calculated from the measured AC inductance, sandwiched between two electrodes with the electrolyte injected into the separator,

The thin leaf material according to claim 1, which has a value represented by:

6. After adding inorganic scaly particles by the fluid spray method while the meta-type aramid short fibers are made into a sheet by the wet papermaking method, the glass transition temperature of the meta-type aramid is transferred between a pair of metal rolls. 2. The method for producing a thin leaf material according to claim 1, wherein high temperature hot pressing is performed at the above temperature.

7. Meta-type aramid short fibers and at least one selected from aramid fibrids and fibrillated aramids are mixed in water, and inorganic scaly particles are formed by a fluid spray method during sheeting by wet papermaking. 3. The method for producing a thin leaf material according to claim 2, wherein after the addition, the obtained sheet is hot-pressed at a temperature not lower than the glass transition temperature of the meta-type aramid between a pair of metal rolls.

8. An electrical / electronic component using the thin leaf material according to any one of claims 1 to 5 as a separator between conductive members.

9. A battery comprising the thin leaf material according to any one of claims 1 to 5 as a separator between conductive members.

10. A capacitor using the thin leaf material according to claim 1 as a separator between conductive members.