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CN-118238487-B - Polyimide composite film, preparation method thereof and flexible printed wiring board

CN118238487BCN 118238487 BCN118238487 BCN 118238487BCN-118238487-B

Abstract

A polyimide composite film and a preparation method thereof and a flexible printed wiring board belong to the field of film materials, wherein the composite film comprises at least three layers, the composite film comprises a first surface layer, a non-thermoplastic polyimide layer and a second surface layer, the non-thermoplastic polyimide layer is arranged between the first surface layer and the second surface layer, the first surface layer and the second surface layer are both thermoplastic polyimide layers, the glass transition temperatures of the first surface layer and the second surface layer are different, and the polyimide composite film has good dimensional stability by controlling the glass transition temperatures of the two surface layers of the polyimide composite film to be different.

Inventors

  • QIU CHANGQUAN
  • ZHANG CHAO
  • XU GANGLEI
  • YUAN MEIJUAN

Assignees

  • 江西巨先新材料科技有限公司

Dates

Publication Date
20260505
Application Date
20240328

Claims (10)

  1. 1. The polyimide composite film is characterized by comprising at least three layers, wherein the composite film comprises a first surface layer, a non-thermoplastic polyimide layer and a second surface layer, the non-thermoplastic polyimide layer is arranged between the first surface layer and the second surface layer, the first surface layer and the second surface layer are both thermoplastic polyimide layers, the glass transition temperatures of the first surface layer and the second surface layer are different, the difference between the glass transition temperatures of the first surface layer and the second surface layer is 20-40 ℃, the glass transition temperature of the first surface layer is 220-260 ℃, and the glass transition temperature of the second surface layer is 200-240 ℃.
  2. 2. The polyimide composite film according to claim 1, wherein the glass transition temperature of the non-thermoplastic polyimide layer is not less than 360 ℃.
  3. 3. The polyimide composite film according to claim 1, wherein the composite film is produced by a coextrusion process.
  4. 4. A method for preparing a polyimide composite film, the method comprising: Obtaining at least one non-thermoplastic polyamic acid and at least two thermoplastic polyamic acids, the thermoplastic polyamic acids comprising a first thermoplastic polyamic acid and a second thermoplastic polyamic acid; preparing at least one non-thermoplastic polyamide acid and at least two thermoplastic polyamide acids into a composite film to obtain a primary product; The initial product is subjected to imidization treatment to obtain a polyimide composite film, the composite film comprises a first surface layer, a non-thermoplastic polyimide layer and a second surface layer, the non-thermoplastic polyimide layer is arranged between the first surface layer and the second surface layer, raw materials of the first surface layer comprise first thermoplastic polyamic acid, raw materials of the second surface layer comprise second thermoplastic polyamic acid, glass transition temperatures of the first surface layer and the second surface layer are different, the difference value of the glass transition temperatures of the first surface layer and the second surface layer is 20-40 ℃, the glass transition temperature of the first surface layer is 220-260 ℃, and the glass transition temperature of the second surface layer is 200-240 ℃.
  5. 5. The method of producing a polyimide composite film according to claim 4, wherein said producing at least one of said non-thermoplastic polyamic acid and at least two of said thermoplastic polyamic acids into a composite film comprises: At least one non-thermoplastic polyamic acid and at least two thermoplastic polyamic acids are combined and co-extruded from a composite slot die head in a die to obtain an intermediate with a multi-layer structure; The intermediate is cast on a stage, wherein a layer having a higher glass transition temperature formed in the intermediate by the first thermoplastic polyamic acid and the second thermoplastic polyamic acid is in contact with the stage.
  6. 6. The method for producing a polyimide composite film according to claim 4, wherein the thermoplastic polyamic acid is produced by polycondensation synthesis of a first diamine and a first dianhydride, and/or The first diamine comprises at least one of 2,2 '-bis [4- (4-aminophenoxy phenyl) ] propane and 4,4' -diaminodiphenyl ether, and/or The first dianhydride comprises at least one of alicyclic dianhydride and aromatic dianhydride, and/or The alicyclic dianhydride comprises at least one of 1,2,4, 5-cyclohexane tetracarboxylic dianhydride and dicyclohexyl-3, 4,3',4' -tetracarboxylic dianhydride, and/or The aromatic dianhydride includes at least one of 4,4'- (4, 4' -isopropyldiphenoxy) diphthalic anhydride and 3,3', 4' -benzophenone tetracarboxylic dianhydride.
  7. 7. The method for producing a polyimide composite film according to claim 6, wherein the molar amount of the alicyclic monomer in the first diamine and the first dianhydride is 10% to 30%.
  8. 8. The method for producing a polyimide composite film according to claim 6, wherein the first diamine comprises 2,2 '-bis [4- (4-aminophenoxyphenyl) ] propane, and the molar amount of the 2,2' -bis [4- (4-aminophenoxyphenyl) ] propane is 10% to 50% of the total molar amount of the first diamine and the first dianhydride.
  9. 9. The method of producing a polyimide composite film according to claim 4, wherein the non-thermoplastic second polyamic acid is produced by polycondensation synthesis of a second diamine and a second dianhydride, and/or The second diamine comprises at least one of p-phenylenediamine, m-phenylenediamine, 4 '-diaminodiphenyl ether, 2' -bis [4- (4-aminophenoxy phenyl) ] propane, 1, 3-bis (4-aminophenoxy) benzene, 4 '-diaminoanilide, 9-bis (4-aminophenyl) fluorene, 4' -diamino-2, 2 '-dimethyl-1, 1' -biphenyl and 4-aminophenyl 4-aminobenzoate, and/or The second dianhydride comprises the mixture of pyromellitic anhydride, 3', at least one of 4,4' -biphenyltetracarboxylic dianhydride, 4' -diphenyl ether dianhydride, 4' - (4, 4' -isopropyldiphenoxy) diphthalic anhydride, 3', 4' -benzophenone tetracarboxylic dianhydride and p-phenylene-bistrimellitate dianhydride.
  10. 10. A flexible printed wiring board, characterized in that the flexible printed wiring board comprises the polyimide composite film according to any one of claims 1 to 3 or the polyimide composite film produced by the method according to any one of claims 4 to 9.

Description

Polyimide composite film, preparation method thereof and flexible printed wiring board Technical Field The application relates to the field of film materials, in particular to a polyimide composite film, a preparation method thereof and a flexible printed wiring board. Background In recent years, with rapid progress in higher performance, higher functionality, and miniaturization of electronic devices, further miniaturization and weight reduction of electronic components used in electronic devices have been demanded. In response to the above-mentioned demands, a packaging method for a semiconductor element and a wiring board on which the semiconductor element is mounted are also required to have high density, high function, and high performance. A flexible printed wiring board (hereinafter also referred to as FPC) is one of important electronic components. FPC is a circuit board with excellent flexibility and pliability, and is widely used in the fields of consumer electronics, automobiles, medical equipment, etc. due to its characteristics of thinness, bendability, crimpability, etc. In general, when manufacturing FPCs, a flexible metal clad laminate is manufactured by using a thin insulating film layer having flexibility as a core film (hereinafter also referred to as a base film or a base material), a polyimide film layer may be generally selected, and a metal foil layer is bonded to the surface of the core film through an adhesive layer made of various adhesive materials by thermocompression bonding. Further, a circuit pattern is formed on the flexible metal clad laminate, and a cover layer (protective film) is formed on the surface of the circuit pattern, thereby manufacturing the FPC. In a photolithography (photolithography) process or an FPC mounting process on a copper-clad laminate, various processes such as bonding, cutting, exposure, etching and the like are performed with reference to an alignment mark (ALIGNMENT MARK) provided in the copper-clad laminate. The processing accuracy in these steps is important in maintaining the reliability of the electronic device on which the FPC is mounted. However, since the copper-clad laminate has a structure in which copper layers and polyimide film layers having different coefficients of thermal expansion are laminated, stress is generated between the layers due to the difference in the coefficients of thermal expansion between the copper layers and the polyimide film layers. Part or all of the stress is relieved when the wiring process is performed by etching the copper layer, and expansion and contraction are generated, resulting in dimensional change of the wiring pattern. Therefore, dimensional change eventually occurs in the FPC stage, which causes poor contact between the wiring or between the wiring and the terminals, and reduces the reliability and yield of the circuit board. Therefore, dimensional stability is a very important characteristic for a copper-clad laminate as a material of a circuit substrate, and dimensional stability of a polyimide film is a key factor affecting dimensional stability of the copper-clad laminate. Disclosure of Invention The application provides a polyimide composite film, a preparation method thereof and a flexible printed wiring board, which can improve the dimensional stability of the polyimide composite film. In a first aspect, an embodiment of the present application provides a polyimide composite film, where the composite film includes at least three layers, and the composite film includes a first surface layer, a non-thermoplastic polyimide layer, and a second surface layer, the non-thermoplastic polyimide layer is disposed between the first surface layer and the second surface layer, the first surface layer and the second surface layer are both thermoplastic polyimide layers, and glass transition temperatures of the first surface layer and the second surface layer are different. According to the technical scheme provided by the embodiment of the application, the glass transition temperatures of the two surface layers of the polyimide composite film are controlled to be different, and in the preparation process, the first surface layer and the second surface layer on the steel belt side and the air side are compounded with the non-thermoplastic polyimide layer of the middle layer, so that the polyimide composite film has good dimensional stability. As an alternative embodiment, the difference between the glass transition temperatures of the first skin layer and the second skin layer is 20-40 ℃. In the implementation process, the difference value of the glass transition temperatures of the first surface layer and the second surface layer is an important factor influencing the dimensional stability of the polyimide composite film, and the through hole controls the difference value of the glass transition temperatures of the first surface layer and the second surface layer to be 20-40 ℃, so that the aim of improving