# US 11,078,378 B2 · Polyimide film, polyimide varnish, and product and layered product using the polyimide film

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- Number: US 11,078,378 B2
- Document ID: US11078378B2
- Status: Granted
- Kind: B2
- Application number: 15/563,480
- Filed: 2016-03-28
- Published: 2018-03-29
- Granted: 2021-08-03
- Earliest claimed: 2015-03-31
- Assignees: Asahi Kasei Kabushiki Kaisha
- Applicants: Asahi Kasei Kabushiki Kaisha
- Inventors: Satoshi Kato; Toshiaki Nagasawa
- Web page: https://patentgrep.com/patent/US11078378B2

## CPC

- C09D 179/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- B32B 27/281: {comprising polyimides}
- B32B 27/34: comprising polyamides
- C08G 73/1042: {Copolyimides derived from at least two different tetracarboxylic compounds or two different diamino compounds}
- C08G 73/1053: {with oxygen only in the tetracarboxylic moiety}
- C08G 73/1064: {containing sulfur}
- C08G 73/1071: {Wholly aromatic polyimides containing oxygen in the form of ether bonds in the main chain}
- C08J 7/0427: {with only one layer of a composition containing a polymer binder (with more layers C08J7/042)}
- C08J 7/046: Forming abrasion-resistant coatings; Forming surface-hardening coatings
- C08J 7/048: Forming gas barrier coatings
- G06F 3/041: Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- B32B 2307/412: Transparent
- B32B 2457/208: Touch screens
- C08G 73/1075: {Partially aromatic polyimides}
- C08J 2379/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C08J 2479/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- G06F 2203/04102: Flexible digitiser, i.e. constructional details for allowing the whole digitising part of a device to be flexed or rolled like a sheet of paper
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- 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)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

To provide polyimide films that contain polyimide good in solubility in solvent and excel lent in workability and that are colorless, transparent and excellent in toughness, polyimide varnishes, and products and layered products using the polyimide film, the polyimide film is characterized by containing polyimide expressed by following general formula (1), and containing as A in the general formula (1), a structure expressed by following general formula (A-1), for example, structure expressed by following general formula (A-5). Herein, in the general formula (1), A represents a bivalent organic group, B represents a tetravalent organic group, and n is 2 or more.

## Claims

### Claim 1

A polyimide film containing:
a polyimide expressed by a following general formula (1); and
a structure expressed by a following general formula (A-1), and at least one or more of structures respectively expressed by a following general formula (A-2), a following general formula (A-3) and a following general formula (A-4), as A in the general formula (1),
wherein among the general formulas (A-2) to (A-4), a general formula (A-5), consisting of the general formula (A-2) and a following general formula (X-1), is at least contained,
wherein as B in the general formula (1), the polyimide film contains at least one of structures respectively expressed by from the following general formulas (B-1) to (B-4),
wherein among the general formulas (B-1) to (B-4), a general formula (B-5), consisting of the following general formula (B-1) and a general formula (Y-1), is at least contained, as B in the general formula (1),
wherein a content of γ-butyrolactone is at least 0.01 mass % and smaller than 3 mass %,
wherein, in the general formula (1), A represents a bivalent organic group, B represents a tetravalent organic group, and n is 2 or more;
in the general formula (A-2), X represents a bivalent organic group selected from following general formulas (X-1) to (X-3);
in the general formula (A-3), a is 0 or 1;
wherein, in the general formula (B-1), Y represents one of structures selected from following general formula (Y-1) to general formula (Y-3);
wherein a Yellow Index (YI) is 4 or less,
wherein the structure expressed by the general formula (A-1) is derived from 3,3′-diaminodiphenyl sulfone (3, 3′-DDS),
wherein the structure expressed by the general formula (A-5) is derived from 4,4′-diaminodiphenyl sulfone (4, 4′-DDS),
wherein the structure expressed by the general formula (B-5) is derived from 4,4′-oxydiphthalic dianhydride (ODPA), and
wherein the 3,3′-DDS is provided at a molar ratio range of 20% to 80% of total constituents of the 3, 3′-DDS and the 4, 4′-DDS.

### Claim 2 (depends on 1)

The polyimide film according to claim 1, wherein a film thickness of the film ranges from 1 μm to 5 μm.

### Claim 3 (depends on 1)

The polyimide film according to claim 1, wherein a weight average molecular weight (Mw) of the polyimide is 30,000 or more.

### Claim 4 (depends on 1)

A product using the polyimide film according to claim 1.

### Claim 5 (depends on 1)

A layered product having the polyimide film according to claim 1, and a transparent electrode layer.

### Claim 6 (depends on 5)

The layered product according to claim 5, wherein the product has at least one or more layers of the transparent electrode layer on each of both surfaces of the polyimide film.

### Claim 7

A polyimide film containing:
a polyimide expressed by following general formula (1); and
a structure expressed by following general formula (A-1) as A in the general formula (1), and a structure expressed by following general formula (A-5);
wherein a structure expressed by a following general formula (B-5) is provided as B in general formula (1),
wherein a content of y-butyrolactone is at least 0.01 mass % and smaller than 3 mass %,
wherein retardation (Rth) is 50 nm or less in a conversion value into a film thickness of 15 μm,
wherein a glass transition temperature (Tg) is within a range of 250° C. to 350° C.,
wherein elongation of the film is 10% or more, and coefficients of thermal expansion α1, α2 meet the following equation (I);
0.95α2/al 1.05 (I)
α1: Coefficient of thermal expansion below a glass transition temperature or less of the film in first measurement,
α2: Coefficient of thermal expansion below the glass transition temperature or less of the film in second measurement,
wherein, in the general formula (1), A represents a bivalent organic group, B represents a tetravalent organic group, and n is 2 or more;
wherein a Yellow Index (YI) is 4 or less,
wherein the structure expressed by the general formula (A-1) is derived from 3,3′-diaminodiphenyl sulfone (3, 3′-DDS),
wherein the structure expressed by the general formula (A-5) is derived from 4,4′-diaminodiphenyl sulfone (4, 4′-DDS),
wherein the structure expressed by the general formula (B-5) is derived from 4,4′-oxydiphthalic dianhydride (ODPA), and
wherein the 3,3′-DDS is provided at a molar ratio range of 20% to 80% of total constituents of the 3, 3′-DDS and the 4, 4′-DDS.