# US 2019/0375894 A1 · Polyimide film, laminate and surface material for display

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- Number: US 2019/0375894 A1
- Document ID: US20190375894A1
- Status: Published application
- Kind: A1
- Application number: 16/323,485
- Filed: 2017-08-08
- Published: 2019-12-12
- Earliest claimed: 2016-08-10
- Assignees: Dai Nippon Printing Co., Ltd.
- Applicants: Dai Nippon Printing Co., Ltd.
- Inventors: Katsuya SAKAYORI; Koudai OKADA; Ayako FURUSE; Keisuke WAKITA; Yoshihiro KOBAYASHI; Aya TAKAO; Takanori MAEDA; Nahomi KANAZAWA; Takayuki OTA
- Web page: https://patentgrep.com/patent/US20190375894A1

## CPC

- C08G 73/1039: {comprising halogen-containing substituents}
- B32B 27/281: {comprising polyimides}
- B32B 27/308: {comprising acrylic (co)polymers}
- C08G 73/1042: {Copolyimides derived from at least two different tetracarboxylic compounds or two different diamino compounds}
- C08G 73/106: {containing silicon}
- C08J 5/18: Manufacture of films or sheets
- C08J 7/0427: {with only one layer of a composition containing a polymer binder (with more layers C08J7/042)}
- C08J 7/043: Improving the adhesiveness of the coatings per se, e.g. forming primers (adhesives in the form of films or foils characterised by the primer layers between the polymer carriers and the adhesives C09J7/50)
- C08J 7/046: Forming abrasion-resistant coatings; Forming surface-hardening coatings
- C09D 179/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- B32B 2307/412: Transparent
- B32B 2307/51: Elastic
- B32B 2457/20: Displays, e.g. liquid crystal displays, plasma displays
- C08J 2379/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- 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)
- 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)

## Abstract

A polyimide film includes a polyimide in which a specific amount of molecular framework containing one or two silicon atoms in its main chain, wherein a total light transmittance measured in accordance with JIS K7361-1 is 85% or more; wherein a yellowness index calculated in accordance with JIS K7373-2006 is 30 or less; wherein a glass transition temperature is in a temperature range of from 150° C. to 400° C.; and wherein a tensile elastic modulus at 25° C. obtained by measuring a 15 mm×40 mm test piece at a tensile rate of 10 mm/min and a chuck distance of 20 mm in accordance with JIS K7127, is 1.8 GPa or more.

## Claims

### Claim 1

A polyimide film comprising a polyimide containing a structure represented by the following general formula (1),
wherein a total light transmittance measured in accordance with JIS K7361-1 is 85% or more;
wherein a yellowness index calculated in accordance with JIS K7373-2006 is 30 or less;
wherein a glass transition temperature is in a temperature range of from 150° C. to 400° C.; and
wherein a tensile elastic modulus at 25° C. obtained by measuring a 15 mm×40 mm test piece at a tensile rate of 10 mm/min and a chuck distance of 20 mm in accordance with JIS K7127, is 1.8 GPa or more:
where R1 is a tetravalent group that is a tetracarboxylic acid residue containing an aromatic ring or aliphatic ring; R2 is a divalent group that is a diamine residue; 10 mol % to 50 mol % of total R2s are diamine residues each containing one or two silicon atoms in a main chain thereof, and 50 mol % to 90 mol % of total R2s are diamine residues each containing no silicon atom and containing an aromatic ring or aliphatic ring; and n is a number of repeating units.

### Claim 2 (depends on 1)

The polyimide film according to claim 1, wherein a birefringence index in the thickness direction at a wavelength of 590 nm, is 0.020 or less.

### Claim 3 (depends on 1)

The polyimide film according to claim 1, wherein, when a static bending test is carried out in accordance with the following static bending test method, an interior angle measured by the test is 120° or more:
[Static bending test method]
A polyimide film test piece cut to a size of 15 mm×40 mm, is bent at a position half the long side so that both long side ends of the polyimide film test piece sandwich upper and lower surfaces of a metal piece having a thickness of 6 mm (100 mm×30 mm×6 mm); they are fixed by tape so that an overlapping margin of each end of the polyimide film test piece with the upper or lower surface of the metal piece, is 10 mm; while being in this state, the metal piece and the fixed polyimide film test piece are sandwiched between glass plates (100 mm×100 mm×0.7 mm) to fix the polyimide film test piece in a state of being bent with an inner diameter of 6 mm; at this time, dummy test pieces are each interposed into a part where the polyimide film test piece is not present between the metal piece and either one of the glass plates, and the glass plates are fixed parallel to one another by tape; the polyimide film test piece bent and fixed in this state, is left to stand for 24 hours in a relative humidity (RH) environment of 60° C.±2° C. and 93%±2%; then, the glass plates and the fixing tape are removed to release force applied to the polyimide film test piece; then, one end of the test piece is fixed, and the interior angle of the polyimide film test piece 30 minutes after the release of the applied force, is measured.

### Claim 4 (depends on 1)

The polyimide film according to claim 1, wherein the polyimide containing the structure represented by the general formula (1) contains an aromatic ring and at least one selected from the group consisting of (i) a fluorine atom, (ii) an aliphatic ring and (iii) a structure that aromatic rings are linked by a sulfonyl group or an alkylene group to which fluorine is optionally bound by substitution.

### Claim 5 (depends on 1)

The polyimide film according to claim 1, wherein, for the polyimide containing the structure represented by the general formula (1), R1 in the general formula (1) is at least one tetravalent group selected from the group consisting of a cyclohexanetetracarboxylic dianhydride residue, a cyclopentanetetracarboxylic dianhydride residue, a dicyclohexane-3,4,3′,4′-tetracarboxylic dianhydride residue, a cyclobutanetetracarboxylic dianhydride residue, a pyromellitic dianhydride residue, a 3,3′,4,4′-biphenyltetracarboxylic dianhydride residue, a 2,2′,3,3′-biphenyltetracarboxylic dianhydride residue, a 4,4′-(hexafluoroisopropylidene)diphthalic anhydride residue, a 3,4′-(hexafluoroisopropylidene)diphthalic anhydride residue, a 3,3′-(hexafluoroisopropylidene)diphthalic anhydride residue, a 4,4′-oxydiphthalic anhydride residue, and a 3,4′-oxydiphthalic anhydride residue.

### Claim 6 (depends on 1)

The polyimide film according to claim 1, wherein, for the polyimide containing the structure represented by the general formula (1), the diamine residue containing no silicon atom and containing an aromatic ring or aliphatic ring, which is R2 in the general formula (1), is at least one divalent group selected from the group consisting of a trans-cyclohexanediamine residue, a trans-1,4-bismethylenecyclohexane diamine residue, a 4,4′-diaminodiphenylsulfone residue, a 3,4′-diaminodiphenylsulfone residue, a 2,2-bis(4-aminophenyl)propane residue, a 2,2-bis(4-aminophenyl)hexafluoropropane residue, and a divalent group represented by the following general formula (2):
where each of R3 and R4 is independently a hydrogen atom, an alkyl group, or a perfluoroalkyl group.

### Claim 7 (depends on 1)

A laminate wherein the polyimide film defined by claim 1 and a hard coat layer containing a polymer of at least one of a radically polymerizable compound and a cationically polymerizable compound, are adjacently disposed.

### Claim 8 (depends on 7)

The laminate according to claim 7,
wherein the radically polymerizable compound is a compound containing two or more (meth)acryloyl groups per molecule, and the cationically polymerizable compound is a compound containing two or more groups per molecule, which are selected from the group consisting of an epoxy group and an oxetanyl group.

### Claim 9 (depends on 1)

A surface material for display, wherein the surface material is the polyimide film defined by claim 1.

### Claim 10 (depends on 9)

The surface material for display according to claim 9, wherein the surface material is a surface material for flexible display.

### Claim 11 (depends on 7)

A surface material for display, wherein the surface material is the laminate defined by claim 7.

### Claim 12 (depends on 11)

The surface material for display according to claim 11, wherein the surface material is a surface material for flexible display.