# US 10,767,014 B2 · Method for manufacturing transparent polyimide film

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- Number: US 10,767,014 B2
- Document ID: US10767014B2
- Status: Granted
- Kind: B2
- Application number: 15/786,672
- Filed: 2017-10-18
- Published: 2019-04-18
- Granted: 2020-09-08
- Earliest claimed: 2017-10-18
- Assignees: Taimide Tech. Inc.
- Applicants: Taimide Tech. Inc.
- Inventors: Wen-Hsuan Chung
- Web page: https://patentgrep.com/patent/US10767014B2

## CPC

- C08G 73/1021: {characterised by the catalyst used}
- C08G 73/1039: {comprising halogen-containing substituents}
- C08J 5/18: Manufacture of films or sheets
- C08J 5/2218: {Synthetic macromolecular compounds}
- C08K 5/3432: Six-membered rings
- C08K 5/3465: condensed with carbocyclic rings
- C08L 79/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C08J 2379/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C08L 2201/10: Transparent films; Clear coatings; Transparent materials
- 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)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

The instant disclosure relates to a method for manufacturing a transparent polyimide film, including providing a polyamic acid solution having a fluorine content more than 12%; adding a dehydrating agent and a catalyst into the polyamic acid solution, the dehydrating agent having an equivalent number equal to or larger than 3; and baking the polyamic acid solution under a temperature ranging from 250 to 350° C. for performing a chemical imidization process so that the transparent polyimide film is obtained. The transparent polyimide film has an elongation rate of more than 30% and a b* value in a CIELAB coordinate of less than 3.5.

## Claims

### Claim 1

A method for manufacturing a transparent polyimide film, comprising:
providing a polyamic acid solution having a fluorine content more than 12%, and the polyamic acid solution including 4,4′-(4,4′-isopropylidenediphenoxy)bis-(phthalic anhydride);
adding a dehydrating agent and a catalyst into the polyamic acid solution, the dehydrating agent having an equivalent number equal to or larger than 3;
performing a chemical imidization process to form a polyimide solution; and
baking the polyimide solution under a temperature ranging from 250 to 260° C. so that the transparent polyimide film which has a b* value in a CIELAB coordinate of less than 1.3 is obtained.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the polyamic acid solution contains a diamine monomer containing fluorine and a dianhydride monomer containing fluorine.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the diamine monomer is selected from one or a combination of two of the group consisting of 2,2′-Bis(trifluoromethyl)benzidine and 2,2-Bis [4-(4-aminophenoxy phenyl)] hexafluoropropane.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the dehydrating agent is acetic anhydride.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the catalyst includes methylpyridine and isoquinoline.

### Claim 6 (depends on 3)

The method according to claim 3, wherein the polyaminic acid solution further comprises one or more of the diamine monomers selected from the group consisting of 2,2′-Bis(trifluoromethyl)-4,4′-diaminodiphenyl ether and 9,9-bis (3,5-dimethyl-4-amino benzeneyl) fluorine.

### Claim 7 (depends on 2)

The method according to claim 2, wherein the polyaminic acid solution further comprises one or more dianhydride monomer selected from the group consisting of 4,4′-(hexafluoroisopropylidene)diphthalic anhydride, 3,3′,4,4′-Biphenyltetracarboxylic dianhydride and cyclobutane-1, 2, 3, 4-tetracarboxylic dianhydride.