TW202134320A - Polyimide precursor composition and polyimide film/substrate laminate wherein the composition includes a polyimide precursor, 2-phenylimidazole or benzimidazole, and a solvent - Google Patents

Abstract

The object of the present invention is to provide a polyimide precursor composition that can produce a polyimide film/substrate laminate with a less warpage and an excellent stability, and to provide a manufacturing method of a polyimide film/substrate laminate and flexible electronic devices. The polyimide precursor composition of the present invention is characterized by containing: a polyimide precursor, which is represented by the following general formula (I); an imidazole compound, which is selected from at least one of 2-phenylimidazole and benzimidazole. The content of the imidazole compound relative to one mole of a repeating unit of the polyimide precursor falls within a range of more than 0.01 mole and less than 1 mole. The polyimide precursor composition also includes a solvent. In the general formula (I), 70 mol% or more of X1 is the structure represented by formula (1-1), and 70 mol% or more of Y1 is the formula (D-1) and/or (D-2).

Description

Polyimide precursor composition and polyimide film/substrate laminate

The present invention relates to a polyimide precursor composition suitable for use in electronic devices such as substrates of flexible devices and a polyimide film/substrate laminate with reduced warpage. In addition, the present invention relates to a method for manufacturing a flexible electronic device using the above-mentioned composition.

Polyimide films have excellent heat resistance, chemical resistance, mechanical strength, electrical properties, dimensional stability, etc., so they can be widely used in the fields of electrical and electronic devices, semiconductors, and other fields. On the other hand, in recent years, with the advent of a highly information-oriented society, the development of optical materials such as liquid crystal alignment films or protective films for color filters in the field of optical communication, optical fibers, optical waveguides, and other display devices has been continuously developed. Especially in the field of display devices, light and flexible plastic substrates are being actively researched to replace glass substrates, or to develop displays that can be bent or rolled.

In displays such as liquid crystal displays or organic EL (Electroluminescence) displays, semiconductor elements such as TFT (Thin-Film Transistor) for driving each pixel are formed. Therefore, heat resistance or dimensional stability is required for the substrate. Polyimide films are expected to be used as substrates for displays due to their excellent heat resistance, chemical resistance, mechanical strength, electrical properties, and dimensional stability.

Polyimide is generally colored in yellowish brown, so its use in transmissive devices such as liquid crystal displays with backlights is limited. In recent years, a polyimide with excellent transparency in addition to mechanical and thermal properties is being developed. Films are expected to be used as substrates for displays (see Patent Documents 1 to 3).

In general, it is difficult for a flexible film to maintain flatness, and therefore it is difficult to uniformly and accurately form semiconductor elements such as TFTs, fine wiring, and the like on the flexible film. For example, Patent Document 4 describes "a method for manufacturing a flexible device as a display device or a light-receiving device, which includes the following steps: coating a specific precursor resin composition on a carrier substrate to form a solid Polyimide resin film; forming a circuit on the resin film; peeling the solid resin film on which the circuit is formed on the surface from the carrier substrate".

In addition, regarding a method of manufacturing a flexible device, Patent Document 5 discloses a method including the following steps: forming a polyimide film/glass substrate laminate on a glass substrate and forming a device on a glass substrate. After the required components and circuits, irradiate the laser from the side of the glass substrate to peel off the glass substrate.

Patent Document 6 discloses a polyimide precursor composition and the use of the polyimide precursor composition to produce a polyimide film/glass substrate laminate. The polyimide precursor composition The polyimide precursor composition contains a polyimide precursor composition and an imidazole compound, the polyimine precursor composition includes a tetracarboxylic acid component and a diamine component, one having an alicyclic structure and the other having an aromatic ring The repeating unit of the compound. The polyimide film obtained in the invention of Patent Document 6 has a small retardation (retardation) in the thickness direction, excellent mechanical properties, and also excellent transparency. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2012/011590 [Patent Document 2] International Publication No. 2013/179727 [Patent Document 3] International Publication No. 2014/038715 [Patent Document 4] Japanese Patent Laid-Open No. 2010-202729 [Patent Document 5] International Publication No. 2018/221607 [Patent Document 6] International Publication No. 2015/080158

[The problem to be solved by the invention]

When the methods of Patent Documents 4 and 5 are applied to actual production, warpage may occur in the polyimide film/glass substrate laminate, which may make it difficult to form elements with high accuracy, or the operability may decrease. Especially when a large glass substrate is used, for example, it is applied to the so-called multi-chamfering process of manufacturing large-scale flexible electronic devices (such as large-scale display devices) or manufacturing multiple flexible electronic devices (such as display devices) from one substrate. In this case, sometimes the warpage will expand to a level that cannot be ignored.

According to the invention of Patent Document 6, a polyimide film with excellent characteristics is obtained as described above, but the problem of warpage of the polyimide film/glass substrate laminate and the stability of the polyimide precursor composition The problems and the composition to solve these problems have not been disclosed.

The present invention was completed in view of the previous problems, and its main purpose is to provide a polyimide precursor composition that can produce a polyimide film/substrate laminate with less warpage and excellent stability. Furthermore, an object of one aspect of the present invention is to provide a polyimide film and a polyimide film/substrate laminate obtained by using the above polyimide precursor composition, and further, another aspect of the present invention The purpose of the aspect is to provide a method for manufacturing a flexible electronic device and a flexible electronic device using the above-mentioned polyimide precursor composition. [Technical means to solve the problem]

The main disclosures of this application are summarized as follows.

1. A polyimide precursor composition, characterized in that it contains: Polyimide precursor, which is represented by the following general formula (I); An imidazole compound, which is selected from at least one of 2-phenylimidazole and benzimidazole, and its content is more than 0.01 mol and less than 1 mol relative to 1 mol of the repeating unit of the polyimide precursor described above Within the scope of; and Solvent.

(通式I中，X₁ 為4價脂肪族基或芳香族基，Y₁ 為2價脂肪族基或芳香族基，R₁ 及R₂ 相互獨立地為氫原子、碳數1～6之烷基或碳數3～9之烷基矽烷基，其中，X₁ 之70莫耳%以上為式(1-1)：[化1]

(In the general formula I, X ₁ is a tetravalent aliphatic or aromatic group, Y ₁ is a divalent aliphatic or aromatic group, and R ₁ and R ₂ are independently hydrogen atoms with 1 to 6 carbon atoms. Alkyl group or C3-9 alkylsilyl group, wherein _{more than 70 mol% of X 1} is represented by formula (1-1):

所表示之結構，Y₁ 之70莫耳%以上為式(D-1)及/或(D-2)：[化2]

The structure represented, _{more than 70 mol% of Y 1} is the formula (D-1) and/or (D-2):

所表示之結構)。 2.如上述項1所記載之聚醯亞胺前驅體組合物，其中自該聚醯亞胺前驅體組合物獲得之聚醯亞胺膜以厚度10 μm之膜計之波長400 nm的透光率為75%以上。[化3]

The structure represented). 2. The polyimide precursor composition as described in item 1 above, wherein the polyimide film obtained from the polyimide precursor composition has a light transmittance of 400 nm with a thickness of 10 μm. The rate is more than 75%.

3. The polyimide precursor composition as described in the above item 1 or 2, wherein when the polyimide film obtained from the polyimide precursor composition is a film with a thickness of 10 μm, the elongation at break is More than 10%.

4. The polyimide precursor composition described in any one of the above items 1 to 3, wherein _{90 mol% or more of X 1} is the structure represented by the above formula (1-1).

5. The polyimide precursor composition as described in any one of items 1 to 4 above, which provides a polyimide film, which is used to coat the polyimide precursor composition on a silicon wafer Carry out imidization to produce a 10 μm thick polyimide film/silicon wafer laminate, and use the polyimide film/silicon wafer laminate at a temperature above 80°C and below the glass transition temperature and decomposition temperature Calculate the residual stress between the polyimide film and the silicon wafer at a plurality of temperatures in the lower temperature range. When the residual stress is linearly approximated, the polyimide film is The residual stress is less than 27 MPa. As the above-mentioned plural temperatures for measuring the residual stress, for example, 150°C, 140°C, 130°C, 120°C, and 110°C can be set.

6. A polyimide film obtained from the polyimide precursor composition described in any one of items 1 to 5 above.

7. A polyimide film/substrate laminate, characterized in that it has: A polyimide film obtained from the polyimide precursor composition described in any one of items 1 to 5 above, and Substrate.

8. The laminate according to the above item 7, wherein the base material is a glass substrate.

9. A manufacturing method of a polyimide film/substrate laminate, which has the following steps: (a) Coating the polyimide precursor composition as described in any one of items 1 to 5 above on a substrate; and (b) Heat treatment of the polyimide precursor on the base material, and layer a polyimide film on the base material.

10. The manufacturing method according to the above item 9, wherein the base material is a glass substrate.

11. A method for manufacturing a flexible electronic device, which has the following steps: (a) Coating the polyimide precursor composition as described in any one of items 1 to 5 above on a substrate; (b) Heat treatment of the polyimide precursor on the substrate to produce a polyimide film/substrate laminate formed by laminating a polyimide film on the substrate; (c) forming at least one layer selected from a conductive layer and a semiconductor layer on the polyimide film of the laminate; and (d) The above-mentioned base material and the above-mentioned polyimide film are peeled off.

12. The manufacturing method according to the above item 11, wherein the base material is a glass substrate.

13. A method for evaluating the residual stress of a polyimide film/substrate laminate, which has the following steps: (1) Prepare a polyimide film/reference base material laminate with a polyimide film formed on a base base material; (2) Measure the radius of curvature of the polyimide film/reference substrate laminate at a plurality of measuring temperatures above 80°C; (3) Based on the measured radius of curvature, calculate the residual stress between the polyimide film and the reference substrate in the polyimide film/reference substrate laminate at the measurement temperature; and (4) Calculate the residual stress at a predetermined temperature based on the residual stress at a plurality of measurement temperatures.

14. The method for evaluating residual stress as described in the above item 13, wherein the reference base material is a silicon substrate.

15. The residual stress evaluation method as described in the above item 13 or 14, which further has the following steps: Based on the residual stress of the polyimide film/reference base laminate at a predetermined temperature, the warpage of the polyimide film/target base laminate at a predetermined temperature is estimated.

16. The method for evaluating residual stress as described in the above item 15, wherein the target substrate is a glass substrate. [Effects of Invention]

According to the present invention, it is possible to provide a polyimide precursor composition that can produce a polyimide film/substrate laminate with less warpage and is excellent in stability. According to the embodiment of the polyimide precursor composition of the present invention, in addition to the effect of (i) being able to produce a polyimide film/glass substrate laminate with less warpage, the following effects can also be exerted More than one type: (ii) the obtained polyimide film has excellent transparency; (iii) the obtained polyimide film has excellent mechanical properties such as elongation at break; and (iv) excellent storage stability; In a preferred embodiment, in addition to the effect of (i), all the effects of (ii) to (iv) are also exhibited.

Furthermore, according to one aspect of the present invention, it is possible to provide a polyimide film and a polyimide film/substrate laminate obtained by using the above-mentioned polyimide precursor composition. Furthermore, according to another aspect of the present invention, a method for manufacturing a flexible electronic device and a flexible electronic device using the above-mentioned polyimide precursor composition can be provided.

In this application, the so-called "soft (electronic) device" means that the device itself is flexible, and a semiconductor layer (transistor, diode, etc. as a component) is usually formed on a substrate to complete the device. "Flexible (electronic) devices" and previous FPC (flexible printed wiring boards) mounted with IC (integrated circuit) chips and other relatively "hard" semiconductor components such as COF (Chip On Film) ) And other devices are different. However, in order to operate or control the "soft (electronic) device" of the present application, relatively "hard" semiconductor components such as IC chips are mounted on a flexible substrate, or are electrically connected to the flexible substrate. There is no problem in using it. Examples of flexible (electronic) devices that are suitably used include display devices such as liquid crystal displays, organic EL displays, and electronic paper, solar cells, and light-receiving devices such as CMOS (Complementary Metal Oxide Semiconductor).

Hereinafter, the polyimide precursor composition of the present invention will be described, and then, the manufacturing method of the flexible electronic device will be described.

＜＜Polyimine precursor composition＞＞ The polyimide precursor composition used to form the polyimide film contains a polyimide precursor, an imidazole compound and a solvent. Both the polyimide precursor and the imidazole compound are dissolved in the solvent.

The polyimide precursor has the following general formula (I):

(通式I中，X₁ 為4價脂肪族基或芳香族基，Y₁ 為2價脂肪族基或芳香族基，R₁ 及R₂ 相互獨立地為氫原子、碳數1～6之烷基或碳數3～9之烷基矽烷基) 所表示之重複單元。尤佳為R₁ 及R₂ 為氫原子之聚醯胺酸。於X₁ 及Y₁ 為脂肪族基之情形時，脂肪族基較佳為具有脂環結構之基。[化4]

(In the general formula I, X ₁ is a tetravalent aliphatic or aromatic group, Y ₁ is a divalent aliphatic or aromatic group, and R ₁ and R ₂ are independently hydrogen atoms with 1 to 6 carbon atoms. The repeating unit represented by an alkyl group or a C3-9 alkylsilyl group). Particularly preferred is a polyamide acid in which _{R 1} and R _{2 are hydrogen atoms.} When X ₁ and Y ₁ are an aliphatic group, the aliphatic group is preferably a group having an alicyclic structure.

Among all the repeating units in the polyimide precursor, X _{1 is} preferably 70 mol% or more, which is the structure represented by the following formula (1-1), which is derived from nor 𦯉alkane-2-spiro-α-ring The structure of pentanone-α'-spiro-2"-nor 𦯉ane-5,5",6,6"-tetracarboxylic dianhydride (hereinafter referred to as CpODA if necessary).

[化5]

Among all the repeating units in the polyimide precursor, Y _{1 is} preferably 70 mol% or more, which is the structure represented by the following formula (D-1) and/or (D-2), which is derived from 4,4 The structure of'-diaminobenzylaniline (abbreviated as DABAN if necessary).

[化6]

By using a composition containing such a polyimide precursor, a polyimide film/glass substrate laminate with less warpage can be manufactured. In addition to this effect, by using an appropriate imidazole compound, it can be manufactured Polyimide film with excellent mechanical properties such as transparency and elongation at break.

The polyimide precursor will be described by providing the monomers (tetracarboxylic acid component, diamine component, and other components) _{of X 1} and Y ₁ in the general formula (I), and then the manufacturing method will be described.

In this specification, the tetracarboxylic acid component includes tetracarboxylic acid, tetracarboxylic dianhydride, other tetracarboxylic silane esters, tetracarboxylic acid esters, tetracarboxylic acid chloride and other tetracarboxylic acids used as raw materials for the production of polyimine derivative. Although not particularly limited, in terms of production, it is relatively simple to use tetracarboxylic dianhydride. In the following description, an example of using tetracarboxylic dianhydride as the tetracarboxylic acid component will be described. In addition, the diamine component is a diamine compound _{having two amine groups (-NH 2} ) used as a raw material for the production of polyimine.

In addition, in this specification, the polyimide film refers to two types: a film formed on a (carrier) substrate and present in a laminate, and a film after the substrate is peeled off. In addition, the material constituting the polyimide film, that is, the material obtained by heat-treating the polyimide precursor composition (imidizing) is sometimes referred to as "polyimide material".

<X ₁ and tetracarboxylic acid component> As mentioned above, of all the repeating units in the polyimide precursor, X _{1 is} preferably 70 mol% or more and is a structure represented by formula (1-1), more preferably 80 mol% or more is the structure represented by formula (1-1), more preferably 90 mol% or more is the structure represented by formula (1-1), and most preferably 95 mol% or more (100 mol%) The ear% is also very good) is the structure represented by formula (1-1). The tetracarboxylic dianhydride providing the structure of formula (1-1) as X _{1 is CpODA.}

CpODA may be a mixture of stereoisomers, or may be a specific stereoisomer. Although not particularly limited, as preferred stereoisomers, examples include: trans-endo-endo-norman-2-spiro-α-cyclopentanone-α'-spiro-2"-norman- 5,5'',6,6"-tetracarboxylic dianhydride (CpODA-tee) and cis-endo-endo-nor 𦯉ane-2-spiro-α-cyclopentanone-α'-spiro-2"- Noroxane-5,5",6,6"-tetracarboxylic dianhydride (CpODA-cee).

[化7]

In a preferred embodiment, at least 50 mol% or more of CpODA is CpODA-tee, and more preferably 63 mol% or more is CpODA-tee. In another preferred embodiment, at least 30 mol% or more of CpODA is CpODA-cee, and more preferably 37 mol% or more is CpODA-cee. In another preferred embodiment, in CpODA, the total of CpODA-tee and CpODA-cee is at least 80 mol% or more, and more preferably 83 mol% or more.

_{In the present invention, a tetravalent aliphatic group or aromatic group (referred to as "other X 1} ") other than the structure represented by formula (1-1) may be contained in an amount within a range that does not impair the effects of the present invention as X ₁ . That is, in addition to CpODA, the tetracarboxylic acid component may contain other tetracarboxylic acid derivatives in an amount within a range that does not impair the effects of the present invention. The amount of other tetracarboxylic acid derivatives relative to 100 mol% of the tetracarboxylic acid component is less than 30 mol%, more preferably less than 20 mol%, and still more preferably less than 10 mol% (also preferably 0 mole%).

When "other X ₁ "is a tetravalent group having an aromatic ring, it is preferably a tetravalent group having an aromatic ring having 6 to 40 carbon atoms.

Examples of the tetravalent group having an aromatic ring include the following groups.

(式中，Z₁ 為直接鍵或下述2價基：[化8]

(In the formula, Z ₁ is a direct bond or the following divalent group:

之任一者；其中，式中之Z₂ 為2價有機基，Z_{3 、} Z₄ 分別獨立地為醯胺鍵、酯鍵、羰基鍵，Z₅ 為包含芳香環之有機基)[化9]

Any of them; wherein, in the formula, Z ₂ is a divalent organic group, Z _{3 and} Z ₄ are each independently an amide bond, an ester bond, and a carbonyl bond, and Z ₅ is an organic group containing an aromatic ring)

Specific examples of Z ₂ include aliphatic hydrocarbon groups having 2 to 24 carbon atoms and aromatic hydrocarbon groups having 6 to 24 carbon atoms.

Specific examples of Z ₅ include an aromatic hydrocarbon group having 6 to 24 carbon atoms.

As the tetravalent group having an aromatic ring, the following groups are particularly preferred because the obtained polyimide film can have both high heat resistance and high transparency.

(式中，Z₁ 為直接鍵或六氟亞異丙基鍵)[化10]

(In the formula, Z ₁ is a direct bond or a hexafluoroisopropylidene bond)

Here, when Z ₁ is a direct bond, the obtained polyimide film can have high heat resistance, high transparency, and low linear thermal expansion coefficient, which is more preferable.

_{As another preferred base, Z 1} in the above formula (9) can be listed as the following formula (3A):

所表示之作為含茀基之基之化合物。Z₁₁ 及Z₁₂ 分別獨立地較佳為同為單鍵或2價有機基。作為Z₁₁ 及Z₁₂ ，較佳為包含芳香環之有機基，例如較佳為式(3A1)：[化11]

Shown as a compound containing a tungsten group. Z ₁₁ and Z ₁₂ are each independently preferably a single bond or a divalent organic group. As Z ₁₁ and Z ₁₂ , it is preferably an organic group containing an aromatic ring, for example, the formula (3A1) is preferred:

(Z₁₃ 及Z₁₄ 相互獨立地為單鍵、-COO-、-OCO-或-O-，此處，於Z₁₄ 鍵結於茀基之情形時，較佳為Z₁₃ 為-COO-、-OCO-或-O-且Z₁₄ 為單鍵之結構；R₉₁ 為碳數1～4之烷基或苯基，較佳為甲基，n為0～4之整數，較佳為1) 所表示之結構。[化12]

(Z ₁₃ and Z ₁₄ are independently a single bond, -COO-, -OCO-, or -O-. Here, when Z _{14 is} bonded to a green group, it is preferable that Z ₁₃ is -COO-, -OCO- or -O- and Z ₁₄ is a single bond structure; R ₉₁ is an alkyl group or phenyl group with 1 to 4 carbon atoms, preferably a methyl group, n is an integer of 0 to 4, preferably 1) The structure represented.

As a _{tetracarboxylic acid component that provides a repeating unit of the general formula (I) in which X 1} is a tetravalent group having an aromatic ring, for example, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane can be cited , 4-(2,5-di-oxotetrahydrofuran-3-yl)-1,2,3,4-tetralin-1,2-dicarboxylic acid, pyromellitic acid, 3,3',4, 4'-benzophenone tetracarboxylic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyltetracarboxylic acid, 4,4'-oxydi Phthalic acid, bis(3,4-dicarboxyphenyl) benzene, terphenyl-3,4,3',4'-tetracarboxylic acid, terphenyl-3,4,3',4' -Tetracarboxylic acid, bis-carboxyphenyl dimethyl silane, bis-dicarboxy phenoxy diphenyl sulfide, sulfonyl diphthalic acid; or these tetracarboxylic dianhydrides, tetracarboxylic silane esters, Derivatives such as tetracarboxylic acid ester and tetracarboxylic acid chloride. As the tetracarboxylic acid component that provides the repeating unit of the general formula (I) in which X ₁ is a tetravalent group having a fluorine atom-containing aromatic ring, for example, 2,2-bis(3,4-dicarboxyphenyl) ) Hexafluoropropane or its tetracarboxylic dianhydride, tetracarboxylic silane ester, tetracarboxylic acid ester, tetracarboxylic acid chloride and other derivatives. Furthermore, preferred compounds include: (9H-茀-9,9-diyl)bis(2-methyl-4,1-phenylene)bis(1,3-dioxo-1,3 -Dihydroisobenzofuran-5-carboxylate). The tetracarboxylic acid component may be used alone or in combination of plural kinds.

When "other X ₁ "is a tetravalent group having an alicyclic structure, it is preferably a tetravalent group having an alicyclic structure with 4 to 40 carbon atoms, and more preferably has at least one aliphatic 4-12 member The ring further preferably has an aliphatic 4-membered ring or an aliphatic 6-membered ring. As preferred tetravalent groups having an aliphatic 4-membered ring or an aliphatic 6-membered ring, the following groups can be cited.

(式中，R₃₁ ～R₃₈ 分別獨立地為直接鍵或2價有機基；R₄₁ ～R₄₇ 及R₇₁ ～R₇₃ 分別獨立地表示選自由式：-CH₂ -、-CH=CH-、-CH₂ CH₂ -、-O-、-S-所表示之基所組成之群中之1種；R₄₈ 為包含芳香環或脂環結構之有機基)[化13]

(In the formula, R ₃₁ to R ₃₈ are each independently a direct bond or a divalent organic group; R ₄₁ to R ₄₇ and R ₇₁ to R ₇₃ each independently represent a free _{formula: -CH 2} -, -CH=CH- , -CH ₂ CH ₂ -, -O-, -S-represented by one of the group consisting of groups; R ₄₈ is an organic group containing an aromatic ring or alicyclic structure)

Specific examples of R ₃₁ , R ₃₂ , R ₃₃ , R ₃₄ , R ₃₅ , R ₃₆ , R ₃₇ , and R ₃₈ include direct bonds, or aliphatic hydrocarbon groups with 1 to 6 carbon atoms, or oxygen atoms (-O- ), sulfur atom (-S-), carbonyl bond, ester bond, amide bond.

Regarding the organic group containing an aromatic ring as R ₄₈ , for example, the following groups can be cited.

(式中，W₁ 為直接鍵或2價有機基，n₁₁ ～n₁₃ 分別獨立地表示0～4之整數，R₅₁ 、R₅₂ 、R₅₃ 分別獨立地為碳數1～6之烷基、鹵基、羥基、羧基或三氟甲基)[化14]

(In the formula, W ₁ is a direct bond or a divalent organic group, n ₁₁ to n ₁₃ each independently represent an integer of 0 to 4, and R ₅₁ , R ₅₂ , and R ₅₃ are each independently an alkyl group having 1 to 6 carbon atoms , Halo, hydroxyl, carboxyl or trifluoromethyl)

Specific examples of W ₁ include a direct bond, a divalent group represented by the following formula (5), and a divalent group represented by the following formula (6).

(式(6)中之R₆₁ ～R₆₈ 分別獨立地表示直接鍵或上述式(5)所表示之2價基之任一者)[化15]

_{(R 61} to R ₆₈ in formula (6) each independently represent any one of a direct bond or the divalent group represented by the above formula (5))

As the tetravalent group having an alicyclic structure, the following groups are particularly preferred because the obtained polyimide has high heat resistance, high transparency, and low linear thermal expansion coefficient.

[化16]

As the tetracarboxylic acid component that provides the repeating unit of formula (I) in which X ₁ is a tetravalent group having an alicyclic structure, for example, 1,2,3,4-cyclobutanetetracarboxylic acid, isopropylidene Diphenoxy diphthalic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, [1,1'-bis(cyclohexane)]-3,3',4,4'- Tetracarboxylic acid, [1,1'-bis(cyclohexane)]-2,3,3',4'-tetracarboxylic acid, [1,1'-bis(cyclohexane)]-2,2',3,3'-tetracarboxylic acid, 4,4'-methylene bis(cyclohexane-1,2-dicarboxylic acid), 4,4'-(propane-2,2-diyl)bis( Cyclohexane-1,2-dicarboxylic acid), 4,4'-oxybis(cyclohexane-1,2-dicarboxylic acid), 4,4'-thiobis(cyclohexane-1, 2-dicarboxylic acid), 4,4'-sulfonyl bis(cyclohexane-1,2-dicarboxylic acid), 4,4'-(dimethylsilanediyl)bis(cyclohexane-1) ,2-dicarboxylic acid), 4,4'-(tetrafluoropropane-2,2-diyl) bis(cyclohexane-1,2-dicarboxylic acid), octahydrocyclopentadiene-1, 3,4,6-tetracarboxylic acid, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic acid, 6-(carboxymethyl)bicyclo[2.2.1]heptane-2,3 ,5-Tricarboxylic acid, bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic acid, bicyclo[2.2.2]oct-5-ene-2,3,7,8-tetracarboxylic acid Acid, tricyclo[4.2.2.0 ^2,5 ]decane-3,4,7,8-tetracarboxylic acid, tricyclo[4.2.2.0 ^2,5 ]dec-7-ene-3,4,9,10 -Tetracarboxylic acid, 9-oxatricyclo[ ^{4.2.1.0 2,5} ]nonane-3,4,7,8-tetracarboxylic acid, (4arH,8acH)-decahydro-1t,4t:5c,8c -Dimethynaphthalene-2c,3c,6c,7c-tetracarboxylic acid, (4arH,8acH)-decahydro-1t,4t:5c,8c-dimethynaphthalene-2t,3t,6c,7c-tetracarboxylic acid Acid, decahydro-1,4-ethyl bridge-5,8-methyl bridge naphthalene-2,3,6,7-tetracarboxylic acid, tetradecahydro-1,4:5,8:9,10-trimethyl bridge Anthracene-2,3,6,7-tetracarboxylic acid; or such derivatives of tetracarboxylic dianhydride, silane tetracarboxylic acid, tetracarboxylic acid ester, tetracarboxylic acid chloride, etc. The tetracarboxylic acid component may be used alone or in combination of plural kinds.

<Y ₁ and diamine component> As mentioned above, among all the repeating units in the polyimide precursor, Y _{1 is} preferably 70 mol% or more and is represented by the formula (D-1) and/or (D-2) The structure represented is more preferably 80 mol% or more. It is the structure represented by formula (D-1) and/or (D-2), and more preferably 90 mol% or more (also preferably 100 mol%) %) is the structure represented by formula (D-1) and/or (D-2). The structure of formula (D-1) and formula (D-2) is provided as _{the diamine compound of Y 1} as 4,4'-diaminobenzaniline (abbreviation: DABAN).

(式中，m表示0～3，n1及n2分別獨立地表示0～4之整數，B₁ 及B₂ 分別獨立地表示選自由碳數1～6之烷基、鹵基或碳數1～6之氟烷基所組成之群中之1種，X分別獨立地表示直接鍵、或選自由式：-NHCO-、-CONH-、-COO-、-OCO-所表示之基所組成之群中之1種；但是，上述式(D-1)及(D-2)除外) 所表示之結構作為其他Y₁ 。 m較佳為0、1或2，n1及n2較佳為0或1，B₁ 及B₂ 較佳為甲基或三氟甲基。例如，可列舉如下等結構：m＝0且n1＝0；m＝1且X為直接鍵或-COO-、-OCO-，n1＝n2＝0或1；m＝2且X為直接鍵或-COO-、-OCO-。尤佳之結構為m＝1且X為直接鍵之結構。 式(G-1)之結構較佳為於Y₁ 中占超過0莫耳%且30莫耳%以下之比率，進而較佳為占超過5莫耳%且30莫耳%以下之比率。藉由包含式(G-1)之結構，可保持能夠製造翹曲較小之聚醯亞胺膜/玻璃基材積層體之效果，並且改善斷裂強度等機械特性及光學特性。 尤佳為，包含式(B-1)及/或(B-2)：

所表示之結構作為其他Y₁ 。 又，式(B-1)及(B-2)中，更佳為式(B-2)。又，可以10莫耳%以下(0莫耳%亦較佳)之比率含有除式(D-1)、式(D-2)及式(G-1)以外之「其他Y₁ 」作為Y₁ 。In the present invention, a divalent aliphatic group or aromatic group (abbreviated as " Other Y ₁ ") is regarded as Y ₁ . That is, in addition to DABAN, the diamine component may contain other diamine compounds in an amount within a range that does not impair the effects of the present invention. The amount of other diamine compounds relative to 100 mol% of the diamine component is 30 mol% or less (preferably less than 30 mol%), more preferably 20 mol% or less (preferably less than 20 mol%) %), and more preferably 10 mol% or less (preferably less than 10 mol%) (0 mol% is also preferable). In a preferred aspect of the present invention, the ratio of the structure of formula (D-1) and/or (D-2) _{in Y 1 is less than 100 mol%.} In this case, it is better to include formula (G-1):

(In the formula, m represents 0 to 3, n1 and n2 each independently represent an integer of 0 to 4, and B ₁ and B ₂ each independently represent an alkyl group having 1 to 6 carbons, a halogen group or a carbon number of 1 to One of the group consisting of 6 fluoroalkyl groups, X each independently represents a direct bond, or is selected from the group consisting of groups represented by -NHCO-, -CONH-, -COO-, -OCO- One of the above; however, the structure represented by the above formulas (D-1) and (D-2) is regarded as the other Y ₁ . m is preferably 0, 1, or 2, n1 and n2 are preferably 0 or 1, and B ₁ and B _{2 are} preferably methyl or trifluoromethyl. For example, the following structures can be enumerated: m=0 and n1=0; m=1 and X is a direct bond or -COO-, -OCO-, n1=n2=0 or 1; m=2 and X is a direct bond or -COO-, -OCO-. A particularly preferred structure is a structure in which m=1 and X is a direct bond. Structural formula (G-1) is preferably in the Y ₁ as a percentage of more than 0 mole% and 30 mole% of less, and further preferably accounts for more than 5 mole% and the ratio of 30 mole% or less. By including the structure of formula (G-1), the effect of producing a polyimide film/glass substrate laminate with less warpage can be maintained, and mechanical properties such as breaking strength and optical properties can be improved. Especially preferably, it contains formula (B-1) and/or (B-2):

The structure shown is the other Y ₁ . In addition, among formulas (B-1) and (B-2), formula (B-2) is more preferable. _{In addition, "other Y 1} " other than formula (D-1), formula (D-2) and formula (G-1) may be included as Y at a ratio of 10 mol% or less (0 mol% is also preferable) ₁ .

Furthermore, in another preferred aspect of the present invention, when Y ₁ includes the structure of formula (D-1) and/or (D-2) and the structure of formula (G-1), it is preferably only When these structures are included, the structure of formula (G-1) may be included within 40 mol% (that is, the range of more than 0 mol% and 40 mol% or less). As the structure of formula (G-1), formula (B-1) and/or (B-2) are preferred, and formula (B-2) is particularly preferred. Even if it contains the structure of formula (G-1) within 40 mol%, the effect of producing a polyimide film/glass substrate laminate with less warpage can be maintained, and mechanical properties such as breaking strength and optical properties can be improved. characteristic. _{When "other Y 1} "except for formula (G-1) is a divalent group having an aromatic ring, it is preferably a divalent group having an aromatic ring with 6 to 40 carbon atoms, and more preferably It is a divalent group having an aromatic ring with a carbon number of 6-20.

Examples of the divalent group having an aromatic ring include the following groups. However, the group contained in formula (G-1) is excluded.

(式中，W₁ 為直接鍵或2價有機基，n₁₁ ～n₁₃ 分別獨立地表示0～4之整數，R₅₁ 、R₅₂ 、R₅₃ 分別獨立地為碳數1～6之烷基、鹵基、羥基、羧基或三氟甲基)[化17]

(In the formula, W ₁ is a direct bond or a divalent organic group, n ₁₁ to n ₁₃ each independently represent an integer of 0 to 4, and R ₅₁ , R ₅₂ , and R ₅₃ are each independently an alkyl group having 1 to 6 carbon atoms , Halo, hydroxyl, carboxyl or trifluoromethyl)

Specific examples of W ₁ include a direct bond, a divalent group represented by the following formula (5), and a divalent group represented by the following formula (6).

[化18]

(式(6)中之R₆₁ ～R₆₈ 分別獨立地表示直接鍵或上述式(5)所表示之2價基之任一者)[化19]

_{(R 61} to R ₆₈ in formula (6) each independently represent any one of a direct bond or the divalent group represented by the above formula (5))

Here, when W ₁ is a direct bond or one selected from the group consisting of groups represented by -NHCO-, -CONH-, -COO-, -OCO-, the obtained polyamide can be obtained Amine has high heat resistance, high transparency, and low linear thermal expansion coefficient, so it is particularly preferred. In addition, W _{1 is} also particularly preferred when R ₆₁ to R ₆₈ are direct bonds, or one selected from the group consisting of groups represented by -NHCO-, -CONH-, -COO-, and -OCO- Any one of the divalent groups represented by the above formula (6). _{Among them, when selecting -NHCO- or -CONH-, select "other Y 1} "in a different way from formula (D-1) or formula (D-2).

_{As another preferred base, W 1} in the above formula (4) can be listed as the following formula (3B):

所表示之含茀基之基之化合物。Z₁₁ 及Z₁₂ 分別獨立地較佳為同為單鍵或2價有機基。作為Z₁₁ 及Z₁₂ ，較佳為包含芳香環之有機基，例如較佳為式(3B1)：[化20]

Shown are compounds containing tungsten radicals. Z ₁₁ and Z ₁₂ are each independently preferably a single bond or a divalent organic group. As Z ₁₁ and Z ₁₂ , it is preferably an organic group containing an aromatic ring, for example, the formula (3B1) is preferred:

(Z₁₃ 及Z₁₄ 相互獨立地為單鍵、-COO-、-OCO-或-O-，此處，於Z₁₄ 鍵結於茀基之情形時，較佳為Z₁₃ 為-COO-、-OCO-或-O-且Z₁₄ 為單鍵之結構；R₉₁ 為碳數1～4之烷基或苯基，較佳為苯基，n為0～4之整數，較佳為1) 所表示之結構。[化21]

(Z ₁₃ and Z ₁₄ are independently a single bond, -COO-, -OCO-, or -O-. Here, when Z _{14 is} bonded to a green group, it is preferable that Z ₁₃ is -COO-, -OCO- or -O- and Z ₁₄ is a single bond structure; R ₉₁ is an alkyl group with 1 to 4 carbons or a phenyl group, preferably a phenyl group, n is an integer of 0 to 4, preferably 1) The structure represented.

As another preferable group, a compound in which W ₁ is a phenylene diamine compound in the above formula (4), namely a terphenyldiamine compound, is particularly preferably a compound in which both are para-bonded.

_{As another preferable group, compounds in which R 61} and R ₆₂ are 2,2-propylene _{groups in the structure where W 1} is the first benzene ring of formula (6) in the above formula (4) can be cited.

_{As another preferred base, W 1} in the above formula (4) can be listed as the following formula (3B2):

所表示之化合物。[化22]

The compound represented.

As the diamine component that provides the repeating unit of the general formula (I) in which Y ₁ is a divalent group having an aromatic ring, for example, p-phenylenediamine, m-phenylenediamine, benzidine, 3,3'-diamine Amino-biphenyl, 2,2'-bis(trifluoromethyl)benzidine, 3,3'-bis(trifluoromethyl)benzidine, m-tolidine, 3,4'-diaminobenzene Formaniline, N,N'-bis(4-aminophenyl)p-xylylenedimethamide, N,N'-p-phenylenebis(p-aminobenzamide), 4-aminobenzene Oxy-4-diamino benzoate, bis(4-aminophenyl) terephthalate, biphenyl-4,4'-dicarboxylic acid bis(4-aminophenyl) ester , Phenylene bis(p-aminobenzoate), bis(4-aminophenyl)-[1,1'-biphenyl]-4,4'-dicarboxylate, [1,1 '-Biphenyl]-4,4'-diylbis(4-aminobenzoate), 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3 ,3'-Diaminodiphenyl ether, p-methylenebis(phenylenediamine), 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy) Benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy) Oxy)biphenyl, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, bis(4 -Aminophenyl) sulfide, 3,3'-bis(trifluoromethyl)benzidine, 3,3'-bis((aminophenoxy)phenyl)propane, 2,2'-bis(3 -Amino-4-hydroxyphenyl)hexafluoropropane, bis(4-(4-aminophenoxy)diphenyl)sulfonate, bis(4-(3-aminophenoxy)diphenyl) Sulfur, octafluorobenzidine, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, 3,3 '-Difluoro-4,4'-diaminobiphenyl, 2,4-bis(4-aminoanilino)-6-amino-1,3,5-tris, 2,4-bis( 4-aminoanilino)-6-methylamino-1,3,5-tris, 2,4-bis(4-aminoanilino)-6-ethylamino-1,3,5-tris 𠯤, 2,4-bis(4-aminoanilino)-6-anilino-1,3,5-tris. As the diamine component that provides the repeating unit of the general formula (I) in which Y ₁ is a divalent group having a fluorine atom-containing aromatic ring, for example, 2,2'-bis(trifluoromethyl)benzidine, 3,3'-bis(trifluoromethyl)benzidine, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminobenzene) Yl)hexafluoropropane, 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane. In addition, preferred diamine compounds include: 9,9-bis(4-aminophenyl) pyridium, 4,4'-(((9H-茀-9,9-diyl) bis([1, 1'-biphenyl]-5,2-diyl))bis(oxy))diamine, [1,1':4',1"-terphenyl]-4,4"-diamine, 4 ,4'-([1,1'-binaphthyl]-2,2'-diylbis(oxy))diamine. The diamine component may be used alone or in combination of plural kinds.

When "other Y ₁ "is a divalent group having an alicyclic structure, it is preferably a divalent group having an alicyclic structure with 4-40 carbon atoms, and more preferably has at least one aliphatic 4-12 It is more preferable to have an aliphatic 6-membered ring.

Examples of the divalent group having an alicyclic structure include the following groups.

(式中，V₁ 、V₂ 分別獨立地為直接鍵或2價有機基，n₂₁ ～n₂₆ 分別獨立地表示0～4之整數，R₈₁ ～R₈₆ 分別獨立地為碳數1～6之烷基、鹵基、羥基、羧基或三氟甲基，R₉₁ 、R₉₂ 、R₉₃ 分別獨立地為選自由式：-CH₂ -、-CH=CH-、-CH₂ CH₂ -、-O-、-S-所表示之基所組成之群中之1種)[化23]

(In the formula, V ₁ and V ₂ are each independently a direct bond or a divalent organic group, n ₂₁ to n ₂₆ each independently represent an integer of 0 to 4, and R ₈₁ to R ₈₆ each independently represent a carbon number of 1 to 6 R ₉₁ , R ₉₂ , and R ₉₃ are independently selected from the free _{formula: -CH 2} -, -CH=CH-, -CH ₂ CH ₂ -, (1 of the group consisting of the base represented by -O- and -S-)

Specific examples of V ₁ and V ₂ include a direct bond and the divalent group represented by the above formula (5).

As a divalent group having an alicyclic structure, the following groups are particularly preferred because the obtained polyimide has both high heat resistance and low linear thermal expansion coefficient.

作為具有脂環結構之2價基，其中較佳為下述基。[化24]

As the divalent group having an alicyclic structure, the following groups are preferred among them.

[化25]

As the diamine component that provides the repeating unit of the general formula (I) in which Y ₁ is a divalent group having an alicyclic structure, for example, 1,4-diaminocyclohexane, 1,4-diamino- 2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, 1,4-diamino-2-n-propylcyclohexane, 1,4-diamino-2 -Isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane, 1,4-diamino-2-isobutylcyclohexane, 1,4-diamino- 2-Second Butylcyclohexane, 1,4-Diamino-2-tert-Butylcyclohexane, 1,2-Diaminocyclohexane, 1,3-Diaminocyclobutane, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, diaminodicycloheptane, diaminomethyldicycloheptane, diamine Oxydicycloheptane, diaminomethyloxydicycloheptane, isophorone diamine, diaminotricyclodecane, diaminomethyltricyclodecane, bis(amino ring Hexyl)methane, bis(aminocyclohexyl)isopropylidene, 6,6'-bis(3-aminophenoxy)-3,3,3',3'-tetramethyl-1,1' -Spirobiindan, 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindan. The diamine component may be used alone or in combination of plural kinds.

As the tetracarboxylic acid component and diamine component that provide the repeating unit represented by the above general formula (I), aliphatic tetracarboxylic acids (especially dianhydrides) and/or aliphatic diamines other than alicyclic can be used Any one of them is preferably the content of 100 mol% relative to the total of the tetracarboxylic acid component and the diamine component, preferably less than 30 mol%, more preferably less than 20 mol%, and more preferably It is less than 10 mol% (including 0%).

By containing the structure represented by the formula (4) as "other Y ₁ ", there are cases in which the transparency of the obtained polyimide film can be improved. The specific compound of the structure represented by the formula (4) is p-benzene Diamine compounds such as diamine, 3,3'-bis(trifluoromethyl)benzidine, m-tolidine, 4,4'-bis(4-aminophenoxy)biphenyl. In addition, by including the structure represented by formula (3B) as "other Y ₁ ", there are cases where Tg (Transition Temperature) can be increased or the phase difference (retardation) in the film thickness direction can be reduced, as shown in formula (3B) The specific compound of the structure shown is a diamine compound such as 9,9-bis(4-aminophenyl)sulfonate.

The polyimide precursor can be produced from the above-mentioned tetracarboxylic acid component and diamine component. The polyimide precursor (polyimine precursor containing at least one of the repeating units represented by the above formula (I)) used in the present invention can be classified according to the chemical structure adopted _{by R 1} and R _{2 as:} 1) Polyamide (R ₁ and R ₂ are hydrogen), 2) Polyamide ( _{at least a part of R 1} and R ₂ is an alkyl group), 3) 4) Polysilyl amide (R ₁ And _{at least a part of R 2} is an alkylsilyl group). Furthermore, each of the polyimide precursors in this category can be easily manufactured by the following manufacturing method. However, the production method of the polyimide precursor used in the present invention is not limited to the following production methods.

1) Polyamide The molar ratio of the tetracarboxylic dianhydride and the diamine component as the tetracarboxylic acid component in a solvent is approximately equal to the molar ratio of the diamine component to the tetracarboxylic acid component [diamine component The molar number/the molar number of the tetracarboxylic acid component] is preferably 0.90 to 1.10, more preferably 0.95 to 1.05 ratio, for example, at a relatively low temperature below 120°C while inhibiting imidization By carrying out the reaction, the polyimide precursor can be suitably obtained in the form of a polyimide precursor solution.

There is no limitation on this. More specifically, the diamine is dissolved in an organic solvent or water, and while stirring the solution, tetracarboxylic dianhydride is slowly added at 0 to 120°C, preferably 5 Stir for 1 to 72 hours in the range of ~80°C, thereby obtaining a polyimide precursor. When the reaction is carried out at 80°C or higher, the molecular weight will vary depending on the temperature history during polymerization, and the imidization may proceed due to heat, so there is a possibility that the polyimide precursor cannot be produced stably. The order of addition of the diamine and the tetracarboxylic dianhydride in the above-mentioned manufacturing method tends to increase the molecular weight of the polyimide precursor, so it is preferred. In addition, the order of addition of diamine and tetracarboxylic dianhydride in the above-mentioned production method may be reversed, which is preferable in terms of reducing precipitates. In the case of using water as a solvent, it is preferable to add 1,2-dimethylimidazole in an amount of 0.8 times equivalent or more with respect to the carboxyl group of the polyamide acid (polyimide precursor) produced Such as imidazoles or bases such as triethylamine.

2) Polyurethane After reacting tetracarboxylic dianhydride with any alcohol to obtain diester dicarboxylic acid, it reacts with chlorinating reagents (thionine chloride, oxalic chloride, etc.) to obtain diester dicarboxylic acid chloride. The diester dicarboxylic acid chloride and diamine are stirred at -20 to 120°C, preferably -5 to 80°C for 1 to 72 hours, to obtain a polyimide precursor. When the reaction is carried out at 80°C or higher, the molecular weight will vary depending on the temperature history during polymerization, and the imidization may proceed due to heat, so there is a possibility that the polyimide precursor cannot be produced stably. In addition, by dehydrating and condensing diester dicarboxylic acid and diamine using a phosphorus-based condensing agent, carbodiimide condensing agent, etc., a polyimide precursor can also be easily obtained.

The polyimide precursor obtained by this method is relatively stable, so solvents such as water or alcohol can also be added for reprecipitation and other purification.

3) Polysilyl amide (indirect method) The diamine is reacted with the silylation agent in advance to obtain the silylated diamine. If necessary, the silylated diamine is refined by distillation or the like. Then, dissolve the silylated diamine in the dehydrated solvent, stir while slowly adding tetracarboxylic dianhydride, and stir at 0～120℃, preferably 5～80℃1 ~72 hours, thereby obtaining a polyimide precursor. When the reaction is carried out at 80°C or higher, the molecular weight will vary depending on the temperature history during polymerization, and the imidization may proceed due to heat, so there is a possibility that the polyimide precursor cannot be produced stably.

4) Polysilyl amide (direct method) The polyamide acid solution obtained by using method 1) is mixed with a silylation agent, and stirred at 0 to 120°C, preferably 5 to 80°C for 1 to 72 hours, thereby obtaining a polyimide precursor body. When the reaction is carried out at 80°C or higher, the molecular weight will vary depending on the temperature history during polymerization, and the imidization may proceed due to heat, so there is a possibility that the polyimide precursor cannot be produced stably.

As the silylating agent used in the method 3) and the method 4), it is more suitable to use a silylating agent that does not contain chlorine to eliminate the need to refine the silylated polyamide acid or the obtained polyimide. Examples of silylation agents that do not contain chlorine atoms include: N,O-bis(trimethylsilyl)trifluoroacetamide, N,O-bis(trimethylsilyl)acetamide, and hexamethyl Disilazane. N,O-bis(trimethylsilyl)acetamide and hexamethyldisilazane are particularly preferred because they do not contain fluorine atoms and are low in cost.

In addition, in order to promote the reaction, an amine catalyst such as pyridine, piperidine, and triethylamine may be used in the silylation reaction of the diamine in the method 3). The catalyst can be directly used as a polymerization catalyst for the polyimide precursor.

The solvent used when preparing the polyimide precursor is preferably water or, for example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, Aprotic solvents such as N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, etc., as long as the raw material monomer components can be When the amine precursor is dissolved, any kind of solvent can be used without any problems, so its structure is not particularly limited. Preferably, water or N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N-ethyl-2-pyrrolidone and other amine solvents are used , Γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone and other cyclic ester solvents, ethylene carbonate Ester, propylene carbonate and other carbonate solvents, triethylene glycol and other glycol solvents, m-cresol, p-cresol, 3-chlorophenol, 4-chlorophenol and other phenolic solvents, acetophenone, 1,3 -Dimethyl-2-imidazolidinone, cyclobutane, dimethyl sulfoxide, etc. are used as solvents. Furthermore, other general organic solvents, namely phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2- Methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, tetrahydrofuran, dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol two Methyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, turpentine, mineral spirits , Naphtha-based solvents, etc. In addition, the solvent can also be used in combination of plural kinds.

The production of the polyimide precursor is not particularly limited. The monomer and solvent are added so that the solid component concentration of the polyimide precursor (polyimide conversion mass concentration) becomes, for example, 5 to 45% by mass Carry out the reaction.

The logarithmic viscosity of the polyimide precursor is not particularly limited. Preferably, the logarithmic viscosity of the N-methyl-2-pyrrolidone solution at a concentration of 0.5 g/dL at 30°C is 0.2 dL/g or more, more It is preferably 0.3 dL/g or more, and particularly preferably 0.4 dL/g or more. If the logarithmic viscosity is 0.2 dL/g or more, the molecular weight of the polyimide precursor is relatively high, so that the obtained polyimide has excellent mechanical strength or heat resistance.

＜Imidazole compound＞ The polyimide precursor composition contains at least one imidazole compound selected from 2-phenylimidazole and benzimidazole.

The content of the imidazole compound in the polyimide precursor composition can be appropriately selected in consideration of the balance between the additive effect and the stability of the polyimide precursor composition. The amount of the imidazole compound is preferably more than 0.01 mol and less than 1 mol relative to 1 mol of the repeating unit of the polyimide precursor. If the content of the imidazole compound is too small, mechanical properties such as elongation at break may decrease. On the other hand, if the content of the imidazole compound is too large, the storage stability of the polyimide precursor composition may deteriorate.

The content of the imidazole compound relative to 1 mol of the repeating unit is more preferably 0.02 mol or more, more preferably 0.025 mol or more, still more preferably 0.05 mol or more, still more preferably 0.8 mol or less, and further It is preferably 0.6 mol or less, and more preferably 0.4 mol or less.

Furthermore, Patent Document 6 (International Publication No. 2015/080158) describes a polyimide precursor composition containing an imidazole compound, but for polyimide containing 2-phenylimidazole and/or benzimidazole The aspect of the excellent storage stability of the amine precursor composition is not disclosed. In addition, the examples of this document disclose the following: Compared with 1,2-dimethylimidazole, 1-methylimidazole, and 2-methylimidazole, it is a combination containing 2-phenylimidazole or benzimidazole The 400 nm light transmittance of the polyimide film made by the material is reduced. On the other hand, from combining 2-phenylimidazole and/or benzimidazole with the preferred polyimide precursor of the present invention (70 mol% or more of _{X 1} is derived from CpODA, 70 mol% or more of _{Y 1} The transparency of the polyimide film made of the composition derived from DABAN) is improved. Contrary to the disclosure of Patent Document 6, the light transmittance at 400 nm is equal to or higher than that of 2-methylimidazole. In addition, it was also confirmed that 2-phenylimidazole and benzimidazole are effective in reducing the coefficient of linear expansion compared with other imidazoles.

<The preparation of polyimide precursor composition> The polyimide precursor composition used in the present invention includes at least one polyimide precursor, at least one imidazole compound, and a solvent.

As the solvent, those described above as the solvent used when preparing the polyimide precursor can be used. Usually, the solvent used in the preparation of the polyimide precursor can be used directly, that is, it is used in the state of the polyimide precursor solution, but it can also be used after dilution or concentration as needed. The imidazole compound is dissolved in the polyimide precursor composition and exists. The concentration of the polyimide precursor is not particularly limited, and it is usually 5 to 45% by mass in terms of polyimide conversion mass concentration (solid content concentration). Here, the mass in terms of polyimide refers to the mass when all the repeating units are completely imidized.

The viscosity (rotational viscosity) of the polyimide precursor of the present invention is not particularly limited. The rotational viscosity measured with an E-type rotary viscometer at a temperature of 25°C and a shear rate of 20 sec ^-1 is preferably 0.01 to 1000 Pa・Sec, more preferably 0.1～100 Pa・sec. In addition, thixotropy can also be imparted as needed. If the viscosity falls within the above-mentioned range, it is easy to handle during coating or film formation, and repulsion is suppressed, and the leveling property is excellent, so a good film can be obtained.

The polyimide precursor composition of the present invention may optionally contain chemical imidizing agents (anhydrides such as acetic anhydride or amine compounds such as pyridine and isoquinoline), antioxidants, ultraviolet absorbers, and fillers (inorganic particles such as silica) Etc.), dyes, pigments, silane coupling agents and other coupling agents, primers, flame retardants, defoamers, leveling agents, rheology control agents (flow aids), etc.

Regarding the preparation of the polyimide precursor composition, it can be prepared by adding and mixing an imidazole compound or a solution of an imidazole compound to the polyimide precursor solution obtained by the method described above. It is also possible to react the tetracarboxylic acid component and the diamine component in the presence of an imidazole compound.

＜＜Manufacturing of polyimide film/substrate laminate and flexible electronic device＞＞ The polyimide film/substrate laminate of the present invention can be manufactured by the following steps: (a) coating the polyimide precursor composition on the substrate; and (b) applying the polyimide precursor composition on the substrate; The said polyimide precursor is heat-processed, and the laminated body (polyimide film/base material laminated body) which laminated|stacked the polyimide film on the said base material is manufactured. The manufacturing method of the flexible electronic device of the present invention uses the polyimide film/substrate laminate manufactured in the above step (a) and step (b), and further has the following steps: (c) Polyimide in the above laminate On the amine film, at least one layer selected from a conductive layer and a semiconductor layer is formed; and (d) peeling the base material and the polyimide film.

The polyimide precursor composition that can be used in the method of the present invention contains a polyimide precursor, an imidazole compound, and a solvent. As the imidazole compound, those described in the item of the above imidazole compound can be used. As the polyimine precursor, those described in the item of the polyimine precursor composition can be used. The preferred polyimine precursor described in the section of the polyimide precursor composition is also preferred in the method of the present invention, and is not particularly limited.

First, in step (a), the polyimide precursor composition is spread on the substrate, and heat treatment is performed to perform imidization and desolvation, thereby forming a polyimide film, thereby A laminate of a base material and a polyimide film (polyimide film/base material laminate) was obtained.

As the substrate, heat-resistant materials are used, such as ceramic materials (glass, alumina, etc.), metal materials (iron, stainless steel, copper, aluminum, etc.), semiconductor materials (silicon, compound semiconductors, etc.), such as plate or sheet Film or sheet substrates such as substrates or heat-resistant plastic materials (polyimide, etc.). Generally speaking, it is preferably a flat and smooth plate shape. Generally used: glass substrates such as soda lime glass, borosilicate glass, alkali-free glass, sapphire glass; semiconductors (including compound semiconductors) such as silicon, GaAs, InP, and GaN Substrate; metal substrates such as iron, stainless steel, copper, aluminum, etc.

In the present invention, a glass substrate is particularly preferred. For glass substrates, flat, smooth, and large areas have been developed so that they can be easily obtained. The warpage problem is especially obvious when the area of the substrate is larger, and the glass substrate is relatively easy to cause warpage in terms of rigidity. Therefore, the application of the present invention can solve the problem when the glass substrate is used. The thickness of a plate-shaped substrate such as a glass substrate is not particularly limited, and if it is easy to handle, it is, for example, 20 μm to 4 mm, preferably 100 μm to 2 mm. In addition, the size of the plate-shaped substrate is not particularly limited. One side (long side in the case of a rectangle) is, for example, about 100 mm to about 4000 mm, preferably about 200 mm to about 3000 mm, and more preferably about 300 mm to Around 2500 mm.

The substrates such as the glass substrates may also be those with an inorganic thin film (such as a silicon oxide film) or a resin thin film formed on the surface.

The method of casting the polyimide precursor composition on the substrate is not particularly limited, and examples include slit coating method, die nozzle coating method, knife coating method, spray coating method, and inkjet coating. Method, nozzle coating method, spin coating method, screen printing method, bar coating method, electrodeposition method and other previously known methods.

In step (b), the polyimide precursor composition is heated on the substrate to convert it into a polyimide film, thereby obtaining a polyimide film/substrate laminate. The heat treatment conditions are not particularly limited. For example, it is preferable to perform drying in a temperature range of 50°C to 150°C, and then at the highest heating temperature, such as 150°C to 600°C, preferably 200°C to 550°C, more preferably 250°C. The treatment is carried out at ℃～500℃. The heat treatment conditions in the case of using a polyimide solution are not particularly limited. The maximum heating temperature is, for example, 100°C to 600°C, preferably 150°C or higher, more preferably 200°C or higher, and more preferably 500°C Hereinafter, it is more preferably 450°C or lower.

The thickness of the polyimide film is preferably 1 μm or more, more preferably 2 μm or more, and still more preferably 5 μm or more. When the thickness is less than 1 μm, the polyimide film cannot maintain sufficient mechanical strength. For example, when it is used as a flexible electronic device substrate, it sometimes fails to withstand the stress sufficiently and is damaged. In addition, the thickness of the polyimide film is preferably 100 μm or less, more preferably 50 μm or less, and still more preferably 20 μm or less. If the thickness of the polyimide film is thick, it may be difficult to reduce the thickness of the flexible device. In order to maintain sufficient durability as a flexible device and further reduce the thickness, the thickness of the polyimide film is preferably 2-50 μm.

In one embodiment, when the polyimide film is measured with a 10 μm thick film, the 400 nm light transmittance is preferably 50% or more, more preferably 70% or more, and more preferably 75% or more, most Preferably, it is more than 80%.

In the present invention, the polyimide film/substrate laminate is characterized by less warpage. The details of the measurement will be described in the following <<Warpage Evaluation, Residual Stress Measurement>>. In one embodiment, the polyimide film/silicon substrate (wafer) laminate When the residual stress between the polyimide film and the silicon substrate is used to evaluate the characteristics of the polyimide film, the residual stress is preferably less than 27 MPa, more preferably less than 25 MPa. Among them, the polyimide film was left in a dry state at 23°C.

If this is the base material, it is converted to the 6th generation Eagle-XG (registered trademark) manufactured by Corning Corporation (glass substrate; vertical size: 1500 mm; horizontal size: 1850 mm; diagonal size: 2382 mm; thickness: 0.5 mm) ; Elastic modulus: 73.6 GPa), the warpage of the 10 μm-thick polyimide film/glass substrate laminate is preferably less than 64 mm in diagonal dimension, and more preferably less than 58 mm. The size of the warpage here refers to the distance from the plane to the periphery when the laminate is placed on a plane as shown in Figure 1.

Furthermore, in one embodiment of the present invention, when the polyimide film is a film with a thickness of 10 μm, the elongation at break is preferably 10% or more.

Furthermore, in another preferred embodiment of the present invention, the breaking strength of the polyimide film is preferably 150 MPa or more, more preferably 170 MPa or more, still more preferably 180 MPa or more, and even more preferably 200 MPa or more, more preferably 210 MPa or more. For the breaking strength, for example, a value obtained from a film having a film thickness of about 5 to 100 μm can be used.

It is particularly preferable to satisfy the above-mentioned desirable characteristics of the polyimide film and the laminate at the same time.

The polyimide film in the polyimide film/substrate laminate may have a second layer such as a resin film or an inorganic film on the surface. That is, after forming the polyimide film on the base material, the second layer may be laminated to form a flexible electronic device substrate. It is preferable to have at least an inorganic film, and it is particularly preferable to be a layer that functions as a barrier layer for water vapor, oxygen (air), or the like. Examples of the water vapor barrier layer include those selected from silicon nitride (SiN _x ), silicon _{oxide (SiO x} ), silicon oxynitride (SiO _x N _y ), aluminum oxide (Al ₂ O ₃ ), and titanium oxide (TiO ₂ ) Inorganic films of inorganic substances in the group consisting of metal oxides, metal nitrides and metal oxynitrides such as zirconium oxide (ZrO _{2 ).} As the film formation methods of these thin films, physical vapor deposition methods such as vacuum vapor deposition, sputtering, ion plating, plasma CVD (chemical vapor deposition, chemical vapor deposition) methods, and catalyst chemical vapor deposition methods are generally known. Chemical vapor deposition methods (chemical vapor deposition method) such as phase deposition method (Cat-CVD method), etc. The second layer can also be a plurality of layers.

When the second layer is a plurality of layers, a resin film and an inorganic film can also be combined. For example, a polyimide film in a polyimide film/substrate laminate can form a three-layer structure, that is, a barrier layer. /Polyimide layer/Example of barrier layer, etc.

In step (c), the polyimide/substrate laminate obtained in step (b) is used to apply a second layer such as an inorganic film on the surface of the polyimide film and On the component), at least one layer selected from a conductive layer and a semiconductor layer is formed. These layers can be formed directly on the polyimide film (including the laminated second layer), or can be formed after other layers required by the laminated device, that is, indirectly formed.

Regarding the conductive layer and/or the semiconductor layer, an appropriate conductive layer and (inorganic, organic) semiconductor layer are selected according to the components and circuits required by the target electronic device. In the step (c) of the present invention, when at least one of the conductive layer and the semiconductor layer is formed, it is also preferable to form at least one of the conductive layer and the semiconductor layer on the polyimide film formed with the inorganic film .

The conductor layer and the semiconductor layer include the entire surface formed on the polyimide film and the part formed on the polyimide film. The present invention can directly move to step (d) after step (c), or after forming at least one layer selected from a conductive layer and a semiconductor layer in step (c), then form a device structure, and then move to step (d) ).

When manufacturing a TFT liquid crystal display device as a flexible device, for example, if necessary, a polyimide film with an inorganic film formed on the entire surface, for example, metal wiring, TFT made of amorphous silicon or polysilicon, and transparent pixel electrodes are formed. . The TFT includes, for example, a gate metal layer, a semiconductor layer such as an amorphous silicon film, a gate insulating layer, and wiring connected to a pixel electrode. The structure required for the liquid crystal display can also be formed on it by a well-known method. In addition, transparent electrodes and color filters can also be formed on the polyimide film.

In the case of manufacturing an organic EL display, for example, a polyimide film with an inorganic film formed on the entire surface as needed, in addition to forming, for example, a transparent electrode, a light-emitting layer, a hole transport layer, an electron transport layer, etc., If necessary, TFTs are formed.

The polyimide film preferred in the present invention is excellent in various properties such as heat resistance and toughness, so the method of forming circuits, components and other structures required for the device is not particularly limited.

Then, in step (d), the substrate and the polyimide film are peeled off. The peeling method may be a mechanical peeling method that physically peels off by applying an external force, or a so-called laser peeling method that peels off by irradiating laser light from the substrate surface.

The structure or parts required by the device are formed or assembled on the (semi-) product with the polyimide film as the substrate after the substrate is peeled off to complete the device.

＜＜Evaluation of warpage and measurement of residual stress＞＞ FIG. 1 schematically shows the warpage of the polyimide film/base material laminate in which the polyimide film 1 is formed on the base material 2. The warpage of the polyimide film/substrate laminate varies according to the elastic modulus of the substrate material. In addition, even if it is the same type of base material, the "warpage value" differs depending on the thickness and size.

Furthermore, according to the research of the present inventors, the polyimide will expand due to moisture absorption, so the degree of warpage of the polyimide film/substrate laminate varies according to the dry state of the polyimide film. In particular, if the evaluation is performed under ambient air and ambient temperature, the polyimide film will absorb moisture and the warpage of the laminate will decrease. In contrast, when manufacturing flexible electronic devices, under vacuum or reduced pressure, or Film formation is performed in an inert atmosphere, and transportation and storage are also performed in a dry atmosphere, so the warpage of the laminate becomes larger. That is, when the measurement is performed in the ambient atmosphere and the ambient temperature, it is impossible to accurately evaluate the warpage that becomes a problem in the manufacture of electronic devices. Therefore, it is preferable to measure the warpage (or residual stress) in a dry state of the polyimide film. Therefore, it is also considered to place the entire measuring device in a dry atmosphere, but it is not practical due to the large scale of the device and the time required for the polyimide membrane to reach an equilibrium state.

The first aspect of the present invention completed in order to solve this problem relates to a method for evaluating the residual stress of a polyimide film/substrate laminate having the following steps: (1) Prepare a polyimide film/reference base material laminate with a polyimide film formed on a base base material; (2) Measure the radius of curvature (warpage) of the polyimide film/reference substrate laminate at a plurality of measuring temperatures above 80°C; (3) Based on the measured radius of curvature (warpage), calculate the residual stress between the polyimide film and the reference substrate in the polyimide film/reference substrate laminate at the measurement temperature; and (4) Calculate the residual stress at a predetermined temperature based on the residual stress at a plurality of measurement temperatures.

In step (1), the reason for using the "reference substrate" is: as mentioned above, the warpage of the polyimide film/substrate laminate varies according to the substrate, so it is used as the "polyimide" When evaluating the properties of the film, it is preferable to use a base material as a standard suitable for measurement (hereinafter referred to as a reference base material). The main purpose of the present invention is to evaluate the warpage of the polyimide film/glass substrate laminate. Therefore, glass substrates can also be used for the following measurements and evaluations. However, in the examples of the present application, a predetermined thickness of silicon is used. The substrate (wafer) serves as the reference base material. The reason is that the reflectance of the surface of the silicon substrate is large, so that the warpage can be easily measured by optical methods. In particular, it is not limited to a silicon substrate, and it can be selected in consideration of a measurement device or method.

According to the above-mentioned manufacturing method of the polyimide film/substrate laminate, (a) the polyimide precursor composition is coated on the reference substrate, and (b) the polyimide precursor is applied to the reference substrate The body is heated, and a polyimide film is laminated on the reference base material to produce a polyimide film/reference base material laminate. This polyimide film/reference base material laminate can be used as a measurement test Sample.

Then, in step (2), the warpage is measured at a relatively high temperature at which the polyimide film is in a dry state. The so-called "relatively high temperature in a dry state" is, for example, 80°C or higher, and more preferably 100°C or higher. The upper limit of the temperature is below the Tg of the polyimide. When no Tg is observed, the decomposition temperature is the upper limit. The reason is that the change in the modulus of elasticity is small below Tg, but if it exceeds Tg, the modulus of elasticity will change significantly. Therefore, in the subsequent step (4), for example, it is not suitable as a measurement point for extrapolation to room temperature. It is usually 250°C or less, preferably 200°C or less. Generally, it is preferably 100°C to 200°C, for example, within the range of 100°C to 150°C.

Therefore, in the method of this aspect, it is sufficient to measure the warpage at a plurality of different temperatures within this temperature range, preferably at 3 or more different temperatures, and more preferably at 4 or more different temperatures. . In addition, although it depends on the measurement method or the measurement device, in order to improve the measurement accuracy, it is also preferable to measure at the same temperature a plurality of times, for example, 3 times or more, for example, about 10 times or more, and find the average value.

Furthermore, as the environment for the measurement method, the measurement device can also be placed in a dry environment such as dry air and inert gas for measurement. However, the environment where the measurement device is placed is for example the normal ambient atmosphere and ambient temperature ( For example, 15℃～30℃, relative humidity 30～60%), the measurement sample and its surroundings will also become the above-mentioned high temperature, so the measurement sample is placed in a very low humidity environment.

"Warpage" can be measured by various methods, and can be expressed by various indicators. The method of optically finding from the reflection angle of light (for example, laser light), etc., is simpler and better. As an example, "warpage" can be expressed by a radius of curvature.

Then, in step (3), based on the measured value of warpage obtained in step (2), the residual stress S is calculated according to Equation 1.

數式1[Number 1]

Formula 1

Here, E/(1-ν): biaxial elastic coefficient (Pa) of the substrate (reference base material: silicon wafer), 1.805E11 Pa for (100) silicon, h: thickness of the substrate (m) t: The thickness of the polyimide film (m) R: The radius of curvature of the test sample (m) 1/R＝1/R ₂ -1/R ₁ R ₁ : The substrate (silicon wafer) before the film is formed alone The radius of curvature R ₂ : the radius of curvature after the film is formed. S: the average value of the residual stress (Pa).

Then, in step (4), based on the residual stress at a plurality of measurement temperatures calculated in step (3), the residual stress at a predetermined temperature is obtained. The predetermined temperature is a temperature that can be selected according to the purpose (Temperature-of-interest) and is not specifically determined. It can be the temperature at which the laminate is used and warpage becomes a problem, or room temperature, such as 23°C, can be used as a reference.

In the example of Fig. 2, the residual stress calculated from 5 different measured temperatures above 100°C is plotted on a graph with temperature as the horizontal axis and residual stress as the vertical axis. In this example, the predetermined temperature is set to 23°C. The method of obtaining the residual stress at the specified temperature from the measuring point is not particularly limited. Generally, as shown in Figure 2, linear approximation (using the least square method) can be performed, and the residual stress at 23°C can be extrapolated to obtain the residual stress at 23°C. stress.

In this way, the properties of the polyimide film can be evaluated by the residual stress between the polyimide film and the silicon substrate (as a reference substrate) at 23°C.

Furthermore, in order to estimate the warpage of the polyimide film/target substrate laminate using the target substrate (for example, a glass substrate) actually used in the manufacture of the device, it is performed as follows. First, the following formula 2 is used to obtain the curvature radius R of the warpage generated in the polyimide film/target substrate laminate.

數式2[Number 2]

Number 2

Here, E: The tensile modulus of elasticity of the target substrate (Pa) h: The thickness of the target substrate (m) t: thickness of polyimide film (m) S: Residual stress (Pa) at 23°C (specified temperature) calculated on the reference base material R: radius of curvature (m).

The radius of curvature calculated from Equation 2 can be substituted into Equation 3, and the warpage (W) shown in Fig. 1 can be calculated and estimated.

數式3[Number 3]

Math 3

Here, L: the length of the target substrate (m), such as diagonal distance, etc.; W: The size of the warpage.

According to the method for evaluating the residual stress of the polyimide film/substrate laminate in the above embodiment, the influence of moisture absorption of the polyimide film can be eliminated, and the following advantageous effects can be obtained. First, if the polyimide film in the laminated body is in a moisture-absorbing state, the warpage is relatively small in most cases, which is different from the warpage generated in the actual step, but the present embodiment can be appropriately evaluated. In addition, it can be evaluated stably without being affected by the measurement environment. Furthermore, since the difference in warpage between the hygroscopic state and the dry state varies according to the composition of the polyimide (because the hygroscopicity varies with the composition), the relative evaluation under the hygroscopic state It is also meaningless, but according to this embodiment, the composition can be accurately compared. [Example]

Hereinafter, the present invention will be further described with examples and comparative examples. In addition, the present invention is not limited to the following examples.

In each of the following examples, the evaluation was performed by the following method.

＜Evaluation of polyimide precursor solution (varnish)＞ [Storage stability] Store the varnish at 23°C. If it is in a uniform and fluid state after 30 days, set it as ○, If it became cloudy or gelled after 30 days, it was set to ×.

＜Evaluation of polyimide film＞ [400 nm transmittance] An ultraviolet-visible spectrophotometer/V-650DS (manufactured by JASCO Corporation) was used to measure the light transmittance of a polyimide film with a thickness of about 10 μm at 400 nm.

[Elastic modulus, breaking elongation, breaking strength] The polyimide film with a film thickness of about 10 μm was punched into a dumbbell shape of IEC450 specification as a test piece, and the initial elasticity was measured with a chuck length of 30 mm and a tensile speed of 2 mm/min using TENSILON manufactured by ORIENTEC. Modulus, breaking elongation, breaking strength.

[Coefficient of Linear Thermal Expansion (CTE)] Cut a polyimide film with a thickness of about 10 μm into a short strip with a width of 4 mm as a test piece, and use TMA/SS6100 (manufactured by Seiko Nano Technology Co., Ltd.) with a length of 15 mm between the chucks. The load is 2 g, and the heating rate is 20°C/min to 500°C. According to the obtained TMA (thermomechanical analysis, thermomechanical analysis) curve, the linear thermal expansion coefficient from 150°C to 250°C is calculated.

[5% weight reduction temperature] A polyimide film with a film thickness of about 10 μm was used as a test piece, and a calorimeter measuring device (Q5000IR) manufactured by TA Instruments was used, and the temperature was raised from 25°C to 600°C at a heating rate of 10°C/min in a nitrogen stream. Calculate the 5% weight loss temperature based on the obtained weight curve.

＜Evaluation of polyimide film/substrate laminate＞ The warpage of the polyimide film/silicon wafer laminate was measured using FLX-2320 manufactured by KLA Tencor. Measure the curvature radius of the silicon wafer in advance under an environment of 23°C and 50%RH. Thereafter, a polyimide film is formed on the silicon wafer. The radius of curvature of the laminate is measured, and the residual stress is calculated. Furthermore, when the curvature radius of the polyimide film/reference substrate laminate is measured under heating, the curvature radius of the silicon wafer alone is also measured at the same temperature.

＜Raw materials＞ The abbreviations and purity of the raw materials used in the following examples are as follows.

[Diamine ingredients] DABAN: 4,4'-diaminobenzaniline PPD: p-phenylenediamine BAPB: 4,4'-bis(4-aminophenoxy)biphenyl TPE-Q: 1,4-bis(4-aminophenoxy)benzene BAFL: 9,9-bis(4-aminophenyl)sulfonate TFMB: 2,2'-bis(trifluoromethyl)benzidine m-TD: m-tolidine

[Tetracarboxylic acid component] CpODA: Norman-2-spiro-α-cyclopentanone-α'-spiro-2"-normanthane-5,5",6,6"-tetracarboxylic dianhydride DNDAxx: (4arH,8acH)-decahydro-1t,4t:5c,8c-dimethyonaphthalene-2t,3t,6c,7c-tetracarboxylic dianhydride PMDA-H: Cyclohexane tetracarboxylic dianhydride CBDA: Cyclobutane tetracarboxylic dianhydride

[Imidazole compound] 2-Pz: 2-Phenylimidazole Bz: Benzimidazole 2-Mz: 2-Methylimidazole

[Solvent] NMP: N-methyl-2-pyrrolidone

Table 1-1 describes the structural formulas of the tetracarboxylic acid components and diamine components used in the Examples and Comparative Examples, and Table 1-2 describes the structural formulas of the imidazole compounds used in the Examples and Comparative Examples.

[Table 1-1] (●Table replacement)

[Table 1-2]

<Example 1> [Preparation of polyimide precursor composition] Add 2.27 g (0.010 mol) of DABAN to the reaction vessel replaced by nitrogen, and add 32.11 g of N-methyl-2-pyrrolidone to make the total mass of the added monomer (the diamine component and the carboxylic acid component) The sum) becomes 16% by mass, and the mixture is stirred at 50°C for 1 hour. Slowly add 3.84 g (0.010 mol) of CpODA to this solution. Stir at 70°C for 4 hours to obtain a uniform and viscous polyimide precursor solution.

2-Phenylimidazole, which is an imidazole compound, was dissolved in 4 times the mass of N-methyl-2-pyrrolidone to obtain a uniform solution with a solid content of 2-phenylimidazole of 20% by mass. The solution of the imidazole compound and the polyimide precursor solution synthesized above were mixed so that the amount of 1 mol imidazole compound relative to the repeating unit of the polyimide precursor became 0.025 mol, and stirred at room temperature After 3 hours, a uniform and viscous polyimide precursor composition was obtained.

[Manufacturing of polyimide film/substrate laminate] In order to manufacture the polyimide film/substrate laminate for evaluating the polyimide film, a 6-inch Eagle-XG (registered trademark) (500 μm thickness) manufactured by Corning Incorporated was used as the glass substrate. Coat the polyimide precursor composition on the glass substrate by a spin coater, and heat it directly on the glass substrate from room temperature to 415°C under nitrogen atmosphere (oxygen concentration below 200 ppm) for thermal imidization , To obtain a polyimide film/substrate laminate. The laminate was put in hot water, the polyimide film was peeled from the glass substrate, and dried, and then the properties of the polyimide film were evaluated. The thickness of the polyimide film is about 10 μm.

[Manufacturing of polyimide film/reference base material laminate] A 6-inch silicon wafer (625 μm thick, (100) substrate) was used as the reference substrate for evaluating the polyimide film. Coat the polyimide precursor composition on the silicon wafer by a spin coater, and heat it directly on the silicon wafer from room temperature to 415°C under a nitrogen atmosphere (oxygen concentration below 200 ppm) for heating Aminated to obtain a polyimide film/reference substrate laminate. The thickness of the polyimide film in the laminate is about 10 μm.

With respect to the obtained polyimide film/reference base material laminate, the curvature radius of warpage was measured at temperatures of 150°C, 140°C, 130°C, 120°C, and 110°C. The measurement was performed 20 times at each temperature and the average value was obtained. Calculate the residual stress at each temperature based on the obtained radius of curvature, and obtain the residual stress at 23°C according to the linear approximation performed by the least square method. In addition, the residual stress was obtained from the radius of curvature of the warpage measured without heating in an environment of 23° C. and 50% RH. The results are shown in Tables 2 to 4. In addition, the calculation uses the 6th generation glass substrate (target substrate) (Eagle-XG (registered trademark); vertical size: 1500 mm; horizontal size: 1850 mm; diagonal size: 2382 mm; thickness: 0.5 mm; modulus of elasticity : 73.6 GPa) The warpage value generated when the polyimide film/base material laminate is produced is shown in Tables 2 to 4 together.

<Examples 2-15, Comparative Examples 1-14> In Example 1, the tetracarboxylic acid component, the diamine component, and the imidazole compound, and the maximum temperature during film formation were changed to the compounds shown in Tables 2 to 5. Except for this, it was produced in the same manner as in Example 1. Polyimide film/reference base material laminate, and the warpage of the laminate was measured in the same manner as in Example 1, and the residual stress at 23°C was determined. The results are shown in Table 2 to Table 5. In addition, in Tables 2 to 4, the same applies to the polyimide film/substrate using the sixth-generation glass substrate (Eagle-XG (registered trademark); 500 μm thickness; elastic modulus: 73.6 GPa) The estimated warpage value of the laminate.

＜Reference example 1～3＞ Table 4 shows the results of evaluating the characteristics of the polyimide film made not on a glass substrate but on a silicon wafer. <Examples 16-22> In Example 1, the tetracarboxylic acid component, the diamine component and the imidazole compound, and the maximum temperature during film formation were changed to the compounds and conditions shown in Table 6, except that glass was used in the same manner as in Example 1. The substrate manufactures a polyimide film/base material laminate. The polyimide film was peeled from the glass substrate in the same manner as in Example 1, and dried, and then the properties of the polyimide film were evaluated. The results are shown in Table 6. In the qualitative observation of the polyimide film/substrate laminate, the warpage was the same as in Examples 2 and 3. In addition, the values of the residual stress and the estimated warpage measured in the same manner as in Example 1 are shown in Table 6.

[Table 2] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Tetracarboxylic acid component (millimolar) CpODA 10 10 10 10 10 10 10 10 10 10 10 10 DNDAxx PMDA-H CBDA Diamine component (millimolar) DABAN 10 10 10 10 10 9.9 8.0 7.0 7.0 10 9.0 8.0 PPD 2.0 BAPB 0.1 2.0 3.0 1.0 BAFL 1.0 2.0 Catalyst composition (millimolar) 2-Pz 0.25 0.5 1 2 4 1 1 1 1 1 1 Bz 1.0 2-Mz Storage stability of varnish 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 Maximum temperature during film making (℃) 415 415 415 415 415 415 405 405 405 415 425 425 Polyimide film Linear thermal expansion coefficient (ppm/K) 12 12 12 12 12 12 18 twenty one 16 12 15 20 Modulus of Elasticity (GPa) 6.6 6.7 6.5 6.4 6.2 6.5 5.2 4.8 5.8 6.7 5.6 4.8 Elongation at break (%) 10 14 17 16 twenty two twenty four 32 38 twenty two 18 14 12 Breaking strength (MPa) 219 234 247 227 244 288 278 284 239 265 214 174 5% weight reduction temperature (℃) 512 513 511 512 513 512 510 506 511 513 510 506 400 nm light transmittance (%) 80 81 81 81 78 81 82 83 83 81 81 79 PI (polyimide, polyimide)/silicon wafer residual stress (Mpa) 23℃ extrapolation 19 19 17 18 17 18 20 twenty four twenty one 19 20 twenty three 23℃ measured value 1.4 0.8 - - - 0.0 4.8 9.5 3.7 0.3 0.9 4.1 PI/glass (G6_2382 mm (diagonal)) warpage (mm) 23℃ extrapolation 45 44 41 41 39 41 47 56 49 44 46 53 23℃ measured value 3 2 - - - 0 11 twenty two 9 1 2 10

[table 3] Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Comparative example 6 Comparative example 7 Comparative example 8 Tetracarboxylic acid component (millimolar) CpODA 10 10 10 10 10 10 10 DNDAxx 10 PMDA-H CBDA Diamine component (millimolar) DABAN 6.0 10 10 10 10 10 10 10 PPD BAPB 4.0 BAFL Catalyst composition (millimolar) 2-Pz 1 10 0.1 2 Bz 0.10 2-Mz 0.5 2 Storage stability of varnish 〇 X X 〇 X 〇 〇 〇 Maximum temperature during film making (℃) 405 415 415 415 415 415 415 430 Polyimide film Linear thermal expansion coefficient (ppm/K) 26 15 14 12 - 12 12 27 Modulus of Elasticity (GPa) 4.3 6.6 6.0 6.5 - 7 7.3 4.5 Elongation at break (%) 43 14 18 6 - 8 8 19 Breaking strength (MPa) 270 226 209 205 - 206 223 162 5% weight reduction temperature (℃) 504 511 510 511 - 512 512 523 400 nm light transmittance (%) 83 81 80 79 - 79 79 80 PI/silicon wafer residual stress (Mpa) 23℃ extrapolation 27 20 20 20 - 20 - 38 23℃ measured value 13.7 - - - - 2.2 - 5.3 PI/glass (G6_2382 mm (diagonal)) warpage (mm) 23℃ extrapolation 64 47 48 47 - 47 - 88 23℃ measured value 32 - - - - 5 - 12

[Table 4] Comparative example 9 Comparative example 10 Comparative example 11 Comparative example 12 Reference example 1 Reference example 2 Reference example 3 Tetracarboxylic acid component (millimolar) CpODA 10 10 10 DNDAxx PMDA-H 10 10 CBDA 10 10 Diamine component (millimolar) DABAN 10 10 10 10 10 7.0 8.0 PPD 2.0 BAPB 1.0 BAFL 2.0 Catalyst composition (millimolar) 2-Pz 2 2 0.5 1 1 Bz 2-Mz Storage stability of varnish 〇 〇 〇 〇 〇 〇 〇 Maximum temperature during film making (℃) 400 400 370 370 415 405 425 Polyimide film Linear thermal expansion coefficient (ppm/K) 55 55 13 11 12 16.1 20 Modulus of Elasticity (GPa) 4.7 4.5 8.6 8.7 6.6 5.7 4.9 Elongation at break (%) 37 42 14 12 15 twenty one 13 Breaking strength (MPa) 185 205 237 257 233 233 181 5% weight reduction temperature (℃) 480 488 479 479 513 511 508 400 nm light transmittance (%) 82 79 53 54 81 82.6 79.2 PI/silicon wafer residual stress (Mpa) 23℃ extrapolation 42 51 twenty three 19 23℃ measured value 1.7 3.9 -8.1 -10.1 PI/glass (G6_2382 mm (diagonal)) warpage (mm) 23℃ extrapolation 97 120 55 45 23℃ measured value 4 9 -19 -twenty four

[table 5] Example 13 Example 14 Comparative example 13 Example 15 Comparative example 14 Tetracarboxylic acid component (millimolar) CpODA 8 7 6 9 9 DNDAxx 1 1 PMDA-H 2 3 4 CBDA Diamine component (millimolar) DABAN 10 10 10 10 10 PPD BAPB BAFL Catalyst composition (millimolar) 2-Pz 2 2 2 2 Bz 2-Mz Storage stability of varnish 〇 〇 〇 〇 〇 Maximum temperature during film making (℃) 415 415 415 415 415 Polyimide film Linear thermal expansion coefficient (ppm/K) 13 16 20 13 12 Modulus of Elasticity (GPa) 6.5 6.1 5.6 6 6.6 Elongation at break (%) twenty three 28 27 16 7 Breaking strength (MPa) 305 296 269 239 208 5% weight reduction temperature (℃) 506 502 499 513 513 400 nm light transmittance (%) 79 78 80 82 78 PI/silicon wafer residual stress (Mpa) 23℃ extrapolation twenty two twenty four 27 19 twenty one 23℃ measured value 0.0 0.5 1.0 0.2 3.2

[Table 6] (●Added) Example 16 Example 17 Example 18 Example 19 Example 20 Example 21 Example 22 Tetracarboxylic acid component (millimolar) CpODA 10 10 10 10 10 10 10 DNDAxx PMDA-H CBDA Diamine component (millimolar) DABAN 9 8 7 9 8 7 6 PPD BAPB BAFL TFMB 1 2 3 4 m-TD 1 2 3 Catalyst composition (millimolar) 2-Pz 1 1 1 1 1 1 1 Bz 2-Mz Storage stability of varnish 〇 〇 〇 〇 〇 〇 〇 Maximum temperature during film making (℃) 415 415 415 415 415 415 415 Polyimide film Linear thermal expansion coefficient (ppm/K) 12 12 12 12 12 13 13 Modulus of Elasticity (GPa) 6.2 6.0 5.7 6.4 6.3 6.2 5.4 Elongation at break (%) 19 16 19 18 19 20 twenty two Breaking strength (MPa) 278 253 272 267 284 302 294 5% weight reduction temperature (℃) 512 511 510 510 506 502 506 400 nm light transmittance (%) 81 83 84 82 82 83 84 PI/silicon wafer residual stress (Mpa) 23℃ extrapolation 18 18 twenty two 18 17 18 twenty three 23℃ measured value 0.8 2.2 5.6 0.4 1.2 2.5 8.8 PI/glass (G6_2382 mm (diagonal)) warpage (mm) 23℃ extrapolation 41 41 51 41 41 41 55 23℃ measured value 2 5 12 1 3 5 twenty one [Industrial availability]

The present invention is suitable for manufacturing flexible electronic devices, such as display devices such as liquid crystal displays, organic EL displays and electronic paper, solar cells, and light receiving devices such as CMOS.

1: Polyimide film 2: Substrate

Fig. 1 is a diagram schematically showing the warpage of the polyimide film/base material laminate. Fig. 2 is a diagram for explaining the method of obtaining the residual stress of the polyimide film/reference base laminate.

1: Polyimide film

2: Substrate

Claims (16)

A polyimide precursor composition, characterized in that it contains: a polyimide precursor, which is represented by the following general formula (I); an imidazole compound, which is selected from the group consisting of 2-phenylimidazole and benzimidazole At least one, and the content thereof is within a range of more than 0.01 mol and less than 1 mol relative to 1 mol of the repeating unit of the polyimide precursor; and a solvent; [化1]

(In the general formula I, X ₁ is a tetravalent aliphatic or aromatic group, Y ₁ is a divalent aliphatic or aromatic group, and R ₁ and R ₂ are independently hydrogen atoms with 1 to 6 carbon atoms. Alkyl group or alkylsilyl group with 3-9 carbon atoms, wherein _{more than 70 mol% of X 1} is represented by formula (1-1): [化2]

The structure represented, _{more than 70 mol% of Y 1} is the formula (D-1) and/or (D-2): [化3]

The structure represented). The polyimide precursor composition of claim 1, wherein when the polyimide film obtained from the polyimide precursor composition is a film with a thickness of 10 μm, the light transmittance at a wavelength of 400 nm is 75% above. According to the polyimide precursor composition of claim 1 or 2, wherein the polyimide film obtained from the polyimide precursor composition is a film with a thickness of 10 μm, the elongation at break is 10% or more. The polyimide precursor composition according to any one of claims 1 to 3, wherein _{more than 90 mole% of X 1} is the structure represented by the above formula (1-1). The polyimide precursor composition according to any one of claims 1 to 4, which provides a polyimide film, and the polyimide precursor composition is coated on a silicon wafer to perform the imine To produce a 10 μm thick polyimide film/silicon wafer laminate, and use the polyimide film/silicon wafer laminate at a temperature above 80℃ and not reach the lower of the glass transition temperature and decomposition temperature Calculate the residual stress between the polyimide film and the silicon wafer at multiple temperatures within the temperature range. When the residual stress is linearly approximated, the residual stress of the polyimide film at 23°C does not reach 27 MPa. A polyimide film obtained from the polyimide precursor composition of any one of claims 1 to 5. A polyimide film/substrate laminate, which is characterized in that it has: A polyimide film obtained from the polyimide precursor composition of any one of claims 1 to 5, and Substrate. The laminate of claim 7, wherein the substrate is a glass substrate. A manufacturing method of a polyimide film/substrate laminate, which has the following steps: (a) Coating the polyimide precursor composition according to any one of claims 1 to 5 on the substrate; and (b) Heat treatment of the polyimide precursor on the base material, and layer a polyimide film on the base material. The manufacturing method of claim 9, wherein the substrate is a glass substrate. A method for manufacturing a flexible electronic device, which has the following steps: (a) Coating the polyimide precursor composition according to any one of claims 1 to 5 on the substrate; (b) Heat treatment of the polyimide precursor on the substrate to produce a polyimide film/substrate laminate formed by laminating a polyimide film on the substrate; (c) forming at least one layer selected from a conductive layer and a semiconductor layer on the polyimide film of the laminate; and (d) The above-mentioned base material and the above-mentioned polyimide film are peeled off. The manufacturing method of claim 11, wherein the substrate is a glass substrate. A method for evaluating the residual stress of a polyimide film/substrate laminate, which has the following steps: (1) Prepare a polyimide film/reference base material laminate with a polyimide film formed on a base base material; (2) Measure the radius of curvature of the polyimide film/reference substrate laminate at a plurality of measuring temperatures above 80°C; (3) Based on the measured radius of curvature, calculate the residual stress between the polyimide film and the reference substrate in the polyimide film/reference substrate laminate at the measurement temperature; and (4) Calculate the residual stress at a predetermined temperature based on the residual stress at a plurality of measurement temperatures. Such as the method for evaluating residual stress in claim 13, wherein the reference substrate is a silicon substrate. For example, the residual stress evaluation method of claim 13 or 14, which further has the following steps: Based on the residual stress of the polyimide film/reference base laminate at a predetermined temperature, the warpage of the polyimide film/target base laminate at a predetermined temperature is estimated. The method for evaluating residual stress in claim 15, wherein the target substrate is a glass substrate.

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