# US 11,028,226 B2 · Heat resistant polyimide film and preparation method thereof

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- Number: US 11,028,226 B2
- Document ID: US11028226B2
- Status: Granted
- Kind: B2
- Application number: 16/307,897
- Filed: 2017-11-02
- Published: 2020-06-04
- Granted: 2021-06-08
- Earliest claimed: 2017-10-16
- Applicants: Institute of Petroleum Chemistry, Heilongjiang Academy of Sciences
- Inventors: Changwei Liu; Wanbao Xiao; Chunyan Qu; Dezhi Wang; Kai Xu; Bo Wang; Hongfeng Li; Hao Feng; Yueyu Guan; Haidong Yang; Haimin Wang; Yang Zhang; Cheng Du; Dongpeng Zhou
- Web page: https://patentgrep.com/patent/US11028226B2

## CPC

- C08G 73/1014: {in the form of (mono)anhydrid}
- B29B 13/00: Conditioning or physical treatment of the material to be shaped (chemical aspects C08J3/00 {; heating, cooling or curing during shaping B29C35/00; thermal after-treatment B29C71/02})
- B29B 13/10: by grinding, e.g. by triturating; by sieving; by filtering
- B29C 41/26: by depositing flowable material on a rotating drum
- B29C 41/44: Articles of indefinite length
- C08G 73/1067: {Wholly aromatic polyimides, i.e. having both tetracarboxylic and diamino moieties aromatically bound}
- C08G 73/1071: {Wholly aromatic polyimides containing oxygen in the form of ether bonds in the main chain}
- C08G 73/1085: {Polyimides with diamino moieties or tetracarboxylic segments containing heterocyclic moieties}
- C08G 73/128: {the unsaturated precursors containing heterocyclic moieties in the main chain}
- C08J 5/18: Manufacture of films or sheets
- C08K 3/14: Carbides
- C08K 3/22: of metals
- C08K 3/28: Nitrogen-containing compounds
- C08K 3/36: Silica
- C08K 3/38: Boron-containing compounds
- C08K 5/544: containing nitrogen
- C08K 7/18: inorganic
- C08K 9/06: with silicon-containing compounds
- C08L 79/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C09D 179/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C09J 11/04: inorganic
- C09J 11/06: organic
- C09J 179/085: {Unsaturated polyimide precursors}
- B29B 2013/005: {Degassing undesirable residual components, e.g. gases, unreacted monomers, from material to be moulded}
- B29K 2079/08: {PI, i.e. polyimides or derivatives thereof}
- B29K 2509/08: Glass
- C08J 2379/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C08K 2003/2224: {Magnesium hydroxide}
- C08K 2003/2227: {of aluminium}
- C08K 2003/2255: {of molybdenum}
- C08K 2003/282: {Binary compounds of nitrogen with aluminium}
- C08K 2003/385: {Binary compounds of nitrogen with boron}
- C08K 2201/003: Additives being defined by their diameter
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- 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)
- 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)
- C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS

## Abstract

A high temperature resistant polyimide film and its preparation method. The present invention relates to a polyimide film and its preparation method and solves the problems of honeycomb's and skin panel's core adhesive—polyimide film with insufficient heat resistance, no climbing of bonding core structure and adhesive fillet formation. The high temperature resistant polyimide film is made by polyimide solution, inorganic filler modifier and interface coupling agent by the steps of: under specific temperature and stirring conditions, adding inorganic filler modifier and interface coupling agent to polyimide solution, stirring to obtain the adhesive agent; filtering and degassing the adhesive agent, casting to a stainless steel drum with carrier cloth and release paper to obtain a self-supporting film; then heating and annealing to obtain the final polyimide film. The present invention is applied to high temperature resistant polyimide film and its preparation method.

## Claims

### Claim 1

A method of preparing heat resistant polyimide film, characterized in that: the method of preparing heat resistant polyimide film comprises the steps of:
(a) weighing to obtain 100 parts by weight of polyimide solution, 10 parts to 40 parts by weight of inorganic filler modifier and 0.1 parts to 5 parts by weight of interface coupling agent; adding the 10 to 40 parts of inorganic filler modifier and the 0.1 parts to 5 parts of interface coupling agent to the 100 parts of polyimide solution under a temperature of 90° C. to 120° C. while stirring; and stirring for 10 minutes to 30 minutes to obtain an adhesive agent;
wherein the polyimide solution is manufactured by a process comprising the steps of:
adding N,N-dimethylacetamide; adding aromatic diamine to the N,N-dimethylacetamide under a nitrogen atmosphere and stirring for 1 hour to 5 hours; then adding aromatic dianhydride and stirring for 1 hour to 5 hours to obtain a mixed solution; adding 4-phenylethynylphthalic anhydride to the mixed solution, stirring and allowing reaction for 1 hour to 5 hours; then adding toluene, heating to a temperature of 120° C. to 130° C. and carrying out reflux reaction for 5 hours to 20 hours under a temperature condition of 120° C.˜130° C. to obtain the polyimide solution;
wherein a molar ratio of the aromatic dianhydride to the aromatic diamine is (0.50˜0.95):1; a mass ratio of the N,N-dimethylacetamide to the toluene is 1:(0.2˜0.5); a molar ratio of the aromatic diamine to 4-phenylethynylphthalic anhydride is 1:(0.01˜1); and a total number of moles of anhydride functional group in the aromatic dianhydride and the 4-phenylethynyl phthalic anhydride is equal to the number of moles of amino functional group of the aromatic diamine;
a ratio of a total mass of the N,N-dimethylacetamide and the toluene to a total mass of the 4-phenylethynylphthalic anhydride, the aromatic dianhydride and the aromatic diamine is (2.5˜4):1;
the aromatic diamine has a structural formula of:
where R1 is O or NH,
(b) filtering and degassing the adhesive agent, casting to a drum made of stainless steel and loaded with carrier cloth and release paper to obtain a self-supporting film; then under a temperature of 60° C. to 150° C., heating for 1 min to 60 min, then under a temperature of 150° C. to 300° C., heating for 1 min to 60 min, and finally under a temperature of 50° C. to 140° C., annealing for 1 min to 20 min to obtain the heat resistant polyimide film;
wherein the heat resistant polyimide film has a thickness of 0.30 mm˜0.60 mm;
in the step (a), the inorganic filler modifier consists of silicon dioxide (silica)-based substance and substance for increasing interface bonding, and the mass ratio of the silica-based substance and the substance for increasing interface bonding is 1:(0.1˜0.5),
the silica-based substance is hollow ceramic microspheres, fumed silica (silicon dioxide in gaseous state), fused silica (melted silicon dioxide) or amorphous silica,
the substance for increasing interface bonding is one or a mixture of two or more selected from the group consisting of: aluminum hydroxide, magnesium hydroxide, molybdenum oxide, aluminum nitride, aluminum oxide, boron nitride and silicon carbide,
in the step (a), the polyimide solution comprises polyimide which has a structural formula of:
where n is 1˜19;
where Ar1 has a structural formula of:
where Ar2 has a structural formula of:
where R1 is O or NH.

### Claim 2 (depends on 1)

The method of preparing heat resistant polyimide film according to claim 1, characterized in that: in the step (a), the inorganic filler modifier has an average particle diameter of 0.1 μm to 10 μm.

### Claim 3 (depends on 1)

The method of preparing heat resistant polyimide film according to claim 1, characterized in that: in the step (a), the interface coupling agent is a silane coupling agent containing amino end group.

### Claim 4 (depends on 3)

The method of preparing heat resistant polyimide film according to claim 3, characterized in that: the silane coupling agent containing amino end group is selected from the group consisting of: γ-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane and 3-aminopropylmethyldiethoxysilane.

### Claim 5 (depends on 1)

The method of preparing heat resistant polyimide film according to claim 1, characterized in that: in the step (b), the carrier cloth is selected from the group consisting of: E-glass fiberglass cloth, D-glass fiberglass cloth, S-glass fiberglass cloth, NE-glass fiberglass cloth, T-glass fiberglass cloth and Q-glass fiberglass cloth.

### Claim 6 (depends on 5)

The method of preparing heat resistant polyimide film according to claim 5, characterized in that: the carrier cloth has a surface density of 100 g/cm2˜110 g/cm2.