# US 2017/0283565 A1 · Thin-film sheet including cellulose fine-fiber layer

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- Number: US 2017/0283565 A1
- Document ID: US20170283565A1
- Status: Published application
- Kind: A1
- Application number: 15/514,447
- Filed: 2015-09-25
- Published: 2017-10-05
- Earliest claimed: 2014-09-26
- Assignees: Asahi Kasei Kabushiki Kaisha
- Applicants: Asahi Kasei Kabushiki Kaisha
- Inventors: Hirofumi ONO; Shuji TAKASU; Yamato SAITO
- Web page: https://patentgrep.com/patent/US20170283565A1

## CPC

- C08J 5/04: Reinforcing macromolecular compounds with loose or coherent fibrous material
- B32B 29/00: Layered products comprising {a layer of} paper or cardboard
- C08J 5/247: {using fibres of at least two types}
- C08J 5/249: {characterised by the additives used in the prepolymer mixture}
- D21H 11/18: Highly hydrated, swollen or fibrillatable fibres
- D21H 13/08: from regenerated cellulose
- H01G 9/02: Diaphragms; Separators
- H01G 11/52: Separators
- H01M 50/443: Particulate material
- H01M 50/489: Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
- H01M 50/491: Porosity
- Y02E 60/10: Energy storage using batteries
- Y02E 60/13: Energy storage using capacitors
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10)
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The present invention provides a thin-film sheet configured from a single layer or a plurality of layers less than or equal to three layers including at least a cellulose fine-fiber layer that includes regenerated cellulose fine fibers by 50 wt % or more, wherein the thin-film sheet achieves improvements in both thermal stability (thermal coefficient of linear expansion and retention of elasticity at high temperature) and sheet strength, and is characterized in that the requirements: (1) the specific surface area equivalent fiber diameter of fibers constituting the cellulose fine-fiber layer is 0.20-2.0 μm inclusive; (2) the air impermeability is 1-100,000 s/100 ml inclusive; and (3) the sheet thickness is 2-22 μm inclusive are satisfied. The present invention also provides a composite sheet, a composite prepreg sheet, a separator for power storage devices, etc., that include the thin-film sheet.

## Claims

### Claim 1

A thin sheet composed of a single layer or multiple layers of three layers or less, which includes at least one layer of a fine cellulose fiber layer containing 50% by weight or more of regenerated fine cellulose fibers, and satisfies the following requirements:
(1) specific surface area equivalent fiber diameter of fibers that compose the fine cellulose fiber layer is 0.20 μm to 2.0 μm,
(2) air impermeability is 1 s/100 ml to 100,000 s/ml, and
(3) sheet thickness is 2 μm to 22 μm.

### Claim 2 (depends on 1)

The thin sheet according to claim 1, wherein the regenerated fine cellulose fibers are contained at 60% by weight or more.

### Claim 3 (depends on 1, 2)

The thin sheet according to claim 1 or 2, wherein the air impermeability is 5 s/100 ml to 40 s/100 ml.

### Claim 4 (depends on 1, 2, 3)

The thin sheet according to any of claims 1 to 3, wherein the sheet thickness is 8 μm to 19 μm.

### Claim 5 (depends on 1, 2, 3, 4)

The thin sheet according to any of claims 1 to 4, wherein the specific surface area equivalent fiber diameter of fibers composing the fine cellulose fiber layer is 0.20 μm to 0.45 μm.

### Claim 6 (depends on 1, 2, 3, 4, 5)

The thin sheet according to any of claims 1 to 5, wherein the basis weight of the fine cellulose fiber layer is 4 g/m2 to 20 g/m2.

### Claim 7 (depends on 1, 2, 3, 4, 5, 6)

The thin sheet according to any of claims 1 to 6, wherein natural fine cellulose fibers are contained in the fine cellulose fiber layer at less than 50% by weight.

### Claim 8 (depends on 7)

The thin sheet according to claim 7, wherein natural fine cellulose fibers are contained in the fine cellulose fiber layer at less than 40% by weight.

### Claim 9 (depends on 1, 2, 3, 4, 5, 6, 7, 8)

The thin sheet according to any of claims 1 to 8, wherein fine fibers composed of an organic polymer other than cellulose are contained in the fine cellulose fiber layer at less than 50% by weight.

### Claim 10 (depends on 9)

The thin sheet according to claim 9, wherein fine fibers composed of a polymer other than the cellulose are contained in the fine cellulose fiber layer at less than 40% by weight.

### Claim 11 (depends on 9, 10)

The thin sheet according to claim 9 or 10, wherein fine fibers composed of an organic polymer other than the cellulose are aramid nanofibers and/or polyacrylonitrile nanofibers.

### Claim 12 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)

The thin sheet according to any of claims 1 to 11, wherein the fine cellulose fiber layer contains a reactive crosslinking agent at 10% by weight or less.

### Claim 13 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)

The thin sheet according to any of claims 1 to 12, wherein a base layer in the form of a nonwoven fabric or paper having a basis weight of 3 g/m2 to 20 g/m2 is contained as one layer of the multilayer structure having three layers or less.

### Claim 14 (depends on 13)

The thin sheet according to claim 13, wherein a base layer in the form of a nonwoven fabric or paper having a basis weight of 3 g/m2 to 15 g/m2 is contained as one layer of the multilayer structure having three layers or less.

### Claim 15 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)

A method for producing the thin sheet according to any of claims 1 to 14 comprising an aqueous papermaking step.

### Claim 16 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)

The method for producing the thin according to any of claims 1 to 14 comprising a coating step.

### Claim 17 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)

A composite sheet in which the thin sheet (A) according to any of claims 1 to 14 is impregnated into a resin (B).

### Claim 18 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)

A composite sheet containing the thin sheet (A) according to any of claims 1 to 14 and one or more resins (B) selected from the group consisting a heat-curable resin, photocurable resin and thermoplastic resin.

### Claim 19 (depends on 18)

The composite sheet according to claim 18, wherein the resin (B) is one or more of any of an epoxy-based resin, acrylic-based resin or general-purpose plastic.

### Claim 20 (depends on 17, 18, 19)

The composite sheet according to any of claims 17 to 19, wherein the resin (B) contains inorganic particles at less than 50% by weight.

### Claim 21 (depends on 20)

The composite sheet according to claim 20, wherein the inorganic particles are one or more types of inorganic particles selected from the group consisting of SiO2, TiO2, Al2O3, ZrO2, MgO, ZnO and BaTiO3 particles.

### Claim 22 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)

A composite prepreg sheet containing the thin sheet (A) according to any of claims 1 to 14 and a heat-curable resin and/or photocurable resin (B).

### Claim 23 (depends on 22)

The composite prepreg sheet according to claim 22, wherein the resin (B) is an epoxy-based resin or acrylic-based resin.

### Claim 24 (depends on 22, 23)

The composite prepreg sheet according to claim 22 or 23, wherein the resin (B) contains inorganic particles at less than 50% by weight.

### Claim 25 (depends on 24)

The composite prepreg sheet according to claim 24, wherein the inorganic particles are one or more types of inorganic particles selected from the group consisting of SiO2, TiO2, Al2O3, ZrO2, MgO, ZnO and BaTiO3 particles.

### Claim 26 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)

A core material for a fiber-reinforced plastic sheet containing the thin sheet according to any of claims 1 to 14.

### Claim 27 (depends on 26)

The core material for a fiber-reinforced plastic sheet according to claim 26, which is a core material for a printed wiring board for electronic materials.

### Claim 28 (depends on 26)

The core material for a fiber-reinforced plastic sheet according to claim 26, which is a core material for an insulating for electronic materials.

### Claim 29 (depends on 26)

The core material for a fiber-reinforced plastic sheet according to claim 26, which is a core material for a core for electronic materials.

### Claim 30 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)

A prepreg for a fiber-reinforced plastic sheet containing the thin sheet according to any of claims 1 to 14.

### Claim 31 (depends on 30)

The prepreg for a fiber-reinforced plastic sheet according to claim 30, which is a prepreg for a printed wiring board for electronic materials.

### Claim 32 (depends on 30)

The prepreg for a fiber-reinforced plastic sheet according to claim 30, which is a prepreg for an insulating for electronic materials.

### Claim 33 (depends on 30)

The prepreg for a fiber-reinforced plastic sheet according to claim 30, which is a prepreg for a core for electronic materials.

### Claim 34 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)

A fiber-reinforced plastic sheet containing the thin sheet according to any of claims 1 to 14.

### Claim 35 (depends on 34)

The fiber-reinforced plastic sheet according to claim 34, which is a printed wiring board for electronic materials.

### Claim 36 (depends on 34)

The fiber-reinforced plastic sheet according to claim 34, which is an insulating for electronic materials.

### Claim 37 (depends on 34)

The fiber-reinforced plastic sheet according to claim 34, which is a core for electronic materials.

### Claim 38 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)

A laminated thin sheet in which an insulating porous layer is formed on one side or both sides of the thin sheet according to any of claims 1 to 14.

### Claim 39 (depends on 38)

The laminated thin sheet according to claim 38, wherein the insulating porous sheet contains an inorganic filler and a resin binder, and the basis weight is 2 g/m2 to 10 g/m2.

### Claim 40 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 38, 39)

A separator for a power storage device containing the thin sheet according to any of claims 1 to 14 or the laminated thin sheet according to claim 38 or 39.

### Claim 41 (depends on 40)

The separator for a power storage device according to claim 40, wherein the power storage device is an electric double-layer capacitor.

### Claim 42 (depends on 40)

The separator for a power storage device according to claim 40, wherein the power storage device is a lithium ion secondary battery.

### Claim 43 (depends on 40)

The separator for a power storage device according to claim 40, wherein the power storage device is a liquid or solid aluminum electrolytic capacitor.

### Claim 44 (depends on 40)

The separator for a power storage device according to claim 40, wherein the power storage device is a lithium ion capacitor.