JP-7856154-B2 - Polyimide precursor composition, polyimide film, and polyimide film/substrate laminate

Inventors

• 岡 卓也
• 根本 雄基
• 小濱 幸徳
• 伊藤 太一

Assignees

• ＵＢＥ株式会社

Dates

Publication Date

20260511

Application Date

20230727

Priority Date

20220729

Claims (14)

1. A polyimide precursor whose repeating unit is represented by the following general formula (I), A polyimide precursor composition comprising, in the production of the polyimide precursor composition, at least one silane compound represented by the formula ( RaO ) nSi ( Rb ) 4-n (wherein n is an integer from 1 to 4, Ra is a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms, and Rb is an alkyl group or aryl group having 10 or less carbon atoms ) present in an amount of more than 0 parts by mass and 60 parts by mass or less per 100 parts by mass of the total of the tetracarboxylic dianhydride and diamine compound, and as an optional component, at least one imidazole compound present in an amount of less than 1 mole per mole of repeating units of the polyimide precursor; (In general formula I, X1 is a tetravalent aliphatic or aromatic group, Y1 is a divalent aliphatic or aromatic group, and R1 and R2 are independently a hydrogen atom, a C1-C6 alkyl group, or a C3-C9 alkylsilyl group, where, X1 satisfies either (i) or (ii), (i) A material containing 50 mol% or more of the structure represented by formula (1-1), and a total of 70 mol% or more of the structure represented by formula (1-1) and the structure represented by formula (1-2), (ii) Containing 70 mol% or more of the structure represented by formula (1-1) and/or the structure represented by formula (1-2), Y1 contains 70 mol% or more of the structure represented by formula (B). ) However, in the case of (ii) above, the condition is that at least one imidazole compound is included as an essential component in an amount of 0.01 moles or more and less than 1 mole per mole of repeating units of the polyimide precursor.
2. The polyimide precursor composition according to claim 1, characterized in that 60 mol% or more of X1 has the structure represented by formula (1-1).
3. The polyimide precursor composition according to claim 1, wherein 80 mol% or more of Y1 has the structure represented by formula (B).
4. The polyimide precursor composition according to claim 1, comprising at least one imidazole compound in an amount of 0.01 moles or more and less than 1 mole per mole of repeating units of the polyimide precursor.
5. The polyimide precursor composition according to claim 4, characterized in that the imidazole compound is at least one selected from the group consisting of 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, 1-phenylimidazole, imidazole, and benzimidazole.
6. A polyimide film obtained from the polyimide precursor composition described in claim 1.
7. A polyimide film obtained from the polyimide precursor composition described in claim 1, A polyimide film/substrate laminate characterized by having a substrate.
8. The laminate according to claim 7, further comprising an inorganic thin film layer on the polyimide film of the laminate.
9. The laminate according to claim 7 or 8, wherein the substrate is a glass substrate.
10. A method for producing a polyimide film/substrate laminate, comprising the steps of (a) applying the polyimide precursor composition described in claim 1 onto a substrate, and (b) heat-treating the polyimide precursor on the substrate to laminate a polyimide film on the substrate.
11. After step (b), (c) The method for manufacturing a laminate according to claim 10, further comprising the step of forming an inorganic thin film layer on the polyimide film of the laminate.
12. A method for manufacturing a flexible electronic device, comprising the steps of (d) forming at least one layer selected from a conductive layer and a semiconductor layer on an inorganic thin film layer of a laminate manufactured according to claim 11, and (e) peeling the substrate from the polyimide film.
13. A flexible electronic device comprising the polyimide film described in claim 6.
14. A flexible electronic device substrate made of the polyimide film described in claim 6.

Description

The present invention relates to a polyimide precursor composition, a polyimide film, and a polyimide film/substrate laminate, which are suitably used in electronic device applications such as substrates for flexible devices. Polyimide films have been widely used in fields such as electrical and electronic devices and semiconductors due to their excellent heat resistance, chemical resistance, mechanical strength, electrical properties, and dimensional stability. Meanwhile, in recent years, with the advent of the advanced information society, development of optical materials such as optical fibers and optical waveguides in the optical communication field, and liquid crystal alignment films and protective films for color filters in the display device field, has been progressing. In particular, in the display device field, there is active research into lightweight and highly flexible plastic substrates as alternatives to glass substrates, and the development of displays that can be bent and rolled. In displays such as liquid crystal displays and organic EL displays, semiconductor elements such as TFTs (thin-film transistors) are formed to drive each pixel. Therefore, the substrate requires heat resistance and dimensional stability. Polyimide film is promising as a substrate for display applications because of its excellent heat resistance, chemical resistance, mechanical strength, electrical properties, and dimensional stability. Generally, flexible films are difficult to maintain flatness, making it difficult to uniformly and accurately form semiconductor elements such as TFTs, fine wiring, etc., on a flexible film. To solve this problem, for example, Patent Document 1 describes "a method for manufacturing a flexible device which is a display device or a light-receiving device, comprising the steps of: coating a specific precursor resin composition onto a carrier substrate to form a solid polyimide resin film; forming a circuit on the resin film; and peeling the solid resin film on which the circuit is formed from the carrier substrate." Furthermore, Patent Document 2 discloses a method for manufacturing a flexible device, which includes forming elements and circuits necessary for the device on a polyimide film/glass substrate laminate obtained by forming a polyimide film on a glass substrate, and then peeling off the glass substrate by irradiating it with a laser from the glass substrate side. In the manufacturing methods for flexible electronic devices described in Patent Documents 1 and 2, appropriate adhesion is required between the polyimide film and the glass substrate in order to handle the polyimide film/glass substrate laminate. Polyimides are generally colored yellowish-brown, which has limited their use in transmissive devices such as liquid crystal displays with backlights. However, in recent years, polyimide films with excellent light transmittance in addition to mechanical and thermal properties have been developed, further increasing expectations for their use as substrates in display applications. For example, Patent Document 3 describes a semi-alicyclic polyimide that has excellent mechanical properties and heat resistance in addition to light transmittance. On the other hand, as aromatic polyimides for flexible electronic device substrate applications, for example, Patent Documents 4 and 5 disclose polyimides using a diamine component containing a fluorine-containing aromatic diamine such as 2,2'-bis(trifluoromethyl)benzidine (TFMB). Furthermore, Patent Documents 6, 7, and 8 disclose examples of using a diamine component containing an aromatic diamine compound containing an ester bond for the same application. Polyimides containing aromatic diamine compounds containing ester bonds are also known for applications in copper-clad laminates (e.g., Patent Document 9) and for forming release layers (Patent Document 10). In addition, Patent Documents 11 to 15 also disclose examples of using a diamine component containing an aromatic diamine compound containing an ester bond. Japanese Patent Publication No. 2010-202729International Publication No. 2018/221607International Publication No. 2012/011590International Publication No. 2009/107429International Publication No. 2019/188265Japanese Patent Publication No. 2021-175790International Publication No. 2017/051827Chinese Patent Application Publication No. 110003470Japanese Patent Publication No. 2021-195380International Publication No. 2016/129546International Publication No. 2021/261177U.S. Patent Application Publication No. 2022/0135797Japanese Unexamined Patent Publication No. 7-133349Japanese Patent Publication No. 2020-164704U.S. Patent Application Publication No. 2021/0017336 In this application, "flexible (electronic) device" means that the device itself is flexible, and typically the device is completed by forming a semiconductor layer (such as transistors and diodes as elements) on a substrate. "Flexible (electronic) devices" are distinguishe