CN116457211A

CN116457211A - Polyimide precursor composition, polyimide film, and polyimide film/substrate laminate

Info

Publication number: CN116457211A
Application number: CN202180078956.1A
Authority: CN
Inventors: 冈卓也; 小滨幸德; 酒井敏仁
Original assignee: Ube Corp
Current assignee: Ube Corp
Priority date: 2020-11-27
Filing date: 2021-11-26
Publication date: 2023-07-18
Anticipated expiration: 2041-11-26
Also published as: TW202227535A; KR20230106702A; WO2022114136A1; JPWO2022114136A1

Abstract

Provided is a polyimide precursor composition which can produce a polyimide film having excellent thermal characteristics and/or heat resistance and also excellent transparency. The polyimide precursor composition contains: a polyimide precursor wherein the repeating unit is composed of a repeating unit represented by the following general formula (I) and a repeating unit further imidized by the general formula (I), and the imidization rate is more than 0% and less than 50%; and (3) a solvent. (in the general formula I, X ₁ 70 mol% or more of (a) is represented by the formula (1-1): the structure shown, Y ₁ 70 mol% or more of (C) is a structure represented by the formula (D-1) and/or (D-2). )

Description

Polyimide precursor composition, polyimide film, and polyimide film/substrate laminate

Technical Field

The present invention relates to a polyimide precursor composition suitable for use in electronic devices such as substrates for flexible devices, a polyimide film having various improved properties, and a polyimide film/substrate laminate. In addition, the present invention relates to a method for producing a flexible electronic device using the above composition.

Background

Polyimide films are widely used in the fields of electric/electronic devices, semiconductors, etc. because of their excellent heat resistance, chemical resistance, mechanical strength, electrical characteristics, dimensional stability, etc. On the other hand, in recent years, with the advent of a highly informative society, development of optical materials such as optical fibers and optical waveguides in the field of optical communication, liquid crystal alignment films and protective films for color filters in the field of display devices has been advanced. In particular, in the field of display devices, research on plastic substrates having light weight and excellent flexibility and development of displays capable of being bent or rolled up are actively being conducted as substitutes for glass substrates.

In a display such as a liquid crystal display or an organic EL display, a semiconductor element such as a TFT for driving each pixel is formed. Therefore, heat resistance and dimensional stability are required for the substrate. Polyimide films are expected to be used as substrates for display applications because of their excellent heat resistance, chemical resistance, mechanical strength, electrical characteristics, dimensional stability, and the like.

Polyimide is generally colored in a tan color, and therefore, is limited in use in a transmissive device such as a liquid crystal display having a backlight, but in recent years, a polyimide film having excellent transparency in addition to mechanical characteristics and thermal characteristics has been developed, and the desire for use as a substrate for display applications has been further improved (see patent documents 1 to 3).

In general, it is difficult to maintain planarity of a flexible film, and therefore it is difficult to uniformly and precisely form semiconductor elements such as TFTs, fine wirings, 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 steps of: a step of forming a polyimide resin film by applying a specific precursor resin composition onto a carrier substrate and forming a film; forming a circuit on the resin film; and a step of peeling the solid resin film having the circuit formed on the surface thereof from the carrier substrate.

In addition, in patent document 5, as a method of manufacturing a flexible device, there is disclosed a method including: after forming elements and circuits necessary for devices on a polyimide film/glass substrate laminate obtained by forming a polyimide film on a glass substrate, laser light is irradiated from the glass substrate side to peel the glass substrate.

Patent document 6 discloses a polyimide precursor composition containing a compound having an alicyclic structure as one of a tetracarboxylic acid component and a diamine component, and containing a repeating unit derived from a compound having an aromatic ring as the other, and an imidazole compound; the polyimide precursor composition is used to produce a polyimide film/glass substrate laminate. The polyimide film obtained by the invention of patent document 6 has a small retardation (retardation) in the thickness direction, is excellent in mechanical properties, and is excellent in transparency.

Patent document 7 describes a polyimide precursor having an imidization ratio of 30 to 90 mol% obtained from a tetracarboxylic acid and a specific diamine compound (see claim 1). When a polyimide film is produced using the polyimide precursor, the advantageous effect of reducing the coefficient of linear thermal expansion can be obtained even without the stretching operation which is often performed in the production of a poly film (polyfilm).

Prior art literature

Patent literature

Patent document 1: international publication No. 2012/01590

Patent document 2: international publication No. 2013/179727

Patent document 3: international publication No. 2014/038715

Patent document 4: japanese patent application laid-open No. 2010-202729

Patent document 5: international publication No. 2018/221607

Patent document 6: international publication No. 2015/080158

Patent document 7: international publication No. 2014/067079

Disclosure of Invention

Problems to be solved by the invention

As described above, the invention of patent document 7 can produce a polyimide film having excellent properties, and is expected to be further improved in various properties such as thermal properties, heat resistance, mechanical properties and transparency in a balanced manner.

The present invention has been made in view of the conventional problems, and a main object thereof is to provide a polyimide precursor composition that can produce a polyimide film that is excellent in thermal characteristics and/or heat resistance and also excellent in transparency. Another object of one embodiment of the present invention is to provide a polyimide film and a polyimide film/substrate laminate obtained using the polyimide precursor composition, and further to provide a method for producing a flexible electronic device and a flexible electronic device using the polyimide precursor composition.

Means for solving the problems

The main disclosures of the present application are summarized as follows

1. A polyimide precursor composition comprising:

a polyimide precursor wherein the repeating unit is composed of a repeating unit represented by the following general formula (I) and a repeating unit further imidized by the general formula (I), and the imidization rate is more than 0% and less than 50%; and

and (3) a solvent.

[ chemical 1]

(in the general formula I, X ₁ Is a 4-valent aliphatic group or an aromatic group, Y ₁ Is a 2-valent aliphatic group or an aromatic group, R ₁ And R is ₂ Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkylsilyl group having 3 to 9 carbon atoms, wherein X ₁ 70 mol% or more of (a) is represented by the formula (1-1):

[ chemical 2]

The structure shown, Y ₁ More than 70 mol% of (C) is represented by the formula (D-1) and/or (D-2):

[ chemical 3]

The structure shown. )

2. The polyimide precursor composition according to item 1, wherein the polyimide film obtained from the polyimide precursor composition has a light transmittance of 79% or more, which is a light transmittance at a wavelength of 400nm in the case of a film having a thickness of 10. Mu.m.

3. The polyimide precursor composition according to the above item 1 or 2, characterized in that a polyimide film obtained from the polyimide precursor composition has a linear thermal expansion coefficient of 20ppm/K or less between 150℃and 250℃in the case of a film having a thickness of 10. Mu.m.

4. The polyimide precursor composition according to any one of the above items 1 to 3, wherein the polyimide obtained from the polyimide precursor composition has a weight loss temperature of 5% at 500 ℃.

5. The polyimide precursor composition according to any one of the above items 1 to 4, wherein the polyimide film obtained from the polyimide precursor composition has an elongation at break of 10% or more in the case of a film having a thickness of 10. Mu.m.

6. A polyimide precursor composition according to any one of the above 1 to 5, wherein X ₁ More than 90 mol% of the catalyst is represented by the above formula (1-1).

7. A polyimide film obtained from the polyimide precursor composition according to any one of the above items 1 to 6.

8. A polyimide film/substrate laminate characterized by comprising:

a polyimide film obtained from the polyimide precursor composition according to any one of the above items 1 to 6; and

a substrate.

9. The laminate according to claim 8, wherein the base material is a glass substrate.

10. A method for producing a polyimide film/substrate laminate, comprising:

(a) A step of applying the polyimide precursor composition according to any one of the above items 1 to 6 to a substrate; and

(b) And a step of heating the polyimide precursor on the substrate to laminate a polyimide film on the substrate.

11. The method according to claim 10, wherein the base material is a glass substrate.

12. A method of manufacturing a flexible electronic device, comprising:

(a) A step of applying the polyimide precursor composition according to any one of the above items 1 to 6 to a substrate;

(b) A step of heating the polyimide precursor on the substrate to produce a polyimide film/substrate laminate in which a polyimide film is laminated on the substrate;

(c) Forming at least 1 layer selected from a conductor layer and a semiconductor layer on the polyimide film of the laminate; and

(d) And peeling the base material from the polyimide film.

13. The method according to claim 12, wherein the base material is a glass substrate.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a polyimide precursor composition capable of producing a polyimide film excellent in thermal characteristics (low linear thermal expansion coefficient, etc.) and/or heat resistance (5% weight loss temperature, etc.) and also excellent in transparency can be provided. According to the embodiment of the polyimide precursor composition of the present invention, there is an effect that a polyimide film excellent in at least one of (i) thermal characteristics such as a low linear thermal expansion coefficient and (ii) heat resistance such as a 5% weight loss temperature and transparency can be produced.

Further, according to one embodiment of the present invention, a polyimide film and a polyimide film/substrate laminate obtained using the polyimide precursor composition can be provided. Further, according to another embodiment of the present invention, a method for manufacturing a flexible electronic device using the polyimide precursor composition and a flexible electronic device can be provided.

Detailed Description

In this application, "flexible (electronic) device" means that the device itself is flexible, and generally, a semiconductor layer (a transistor, a diode, or the like as an element) is formed on a substrate to complete the device. A "flexible (electronic) device" is different from a conventional device such as COF (Chip On Film) in which a "hard" semiconductor element such as an IC Chip is mounted On an FPC (flexible printed circuit board). However, there is no problem in order to operate or control the "flexible (electronic) device" of the present application, in which a "hard" semiconductor element such as an IC chip is mounted on a flexible substrate, or is electrically connected or fused. Examples of flexible (electronic) devices that can be preferably used include liquid crystal displays, organic EL displays, display devices such as electronic papers, solar cells, and light receiving devices such as CMOS.

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

Polyimide precursor composition

A polyimide precursor composition for forming a polyimide film contains a polyimide precursor and a solvent. The polyimide precursor is dissolved in a solvent.

The polyimide precursor contains a repeating unit represented by the following general formula (I) and a repeating unit further imidized by the general formula (I).

[ chemical 4]

(in the general formula I, X ₁ Is a 4-valent aliphatic group or an aromatic group, Y ₁ Is a 2-valent aliphatic group or an aromatic group, R ₁ And R is ₂ Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms. )

The repeating unit of the formula (I) further imidized means a structure in which 1 or 2 of the 2 amide bonds present in the formula (I) are converted into imide bonds, and specifically, are represented by the following formulas (Ib), (Ic) and (II).

[ chemical 5]

[ chemical 6]

[ chemical 7]

The imidization ratio refers to the ratio of conversion of an amide bond to an imide bond in the general formula (I). Therefore, the imidization rate is 0% in the case where all the repeating units in the polyimide precursor are of the general formula (I), 50% in the case where all the repeating units are of the general formulae (Ib) and/or (Ic), and 100% in the case where all the repeating units are of the general formula (II) (i.e., polyimide). In the present invention, an imidization ratio exceeding 0% and less than 50% means that one or more of the general formulae (Ib), (Ic) and (II) are present in such a manner as to achieve a prescribed imidization ratio, in addition to the structure of the general formula (I).

Imidization Rate the polyimide precursor (solution) A kind of electronic device ¹ H-NMR spectrum is calculated from the ratio of the integrated value of the peak (7 to 8.3 ppm) of aromatic proton to the integrated value of the peak (9.5 to 10.5 ppm) of proton of amide.

In addition, the polyimide precursor having the imidization rate adjusted can be produced by a production method comprising the steps of: in the reaction of the tetracarboxylic acid component and the diamine component, or in the reaction of the tetracarboxylic acid component and the diamine component to obtain a precursor having a repeating unit represented by the general formula (I), the reaction is carried out for a suitable time under suitable conditions for the imidization reaction to proceed so as to achieve the desired imidization rate.

As described in detail below, the details can be roughly classified into: a method of allowing imidization to proceed intramolecular uniformly (or randomly) (for simplicity, referred to as a one-stage supply method); and a method in which the tetracarboxylic acid component and the diamine component are separately supplied and only a part of the imidization reaction is performed between the tetracarboxylic acid component and a part of the diamine component (or in blocks) (for simplicity, a multistage supply method is called).

In the one-stage supply method, when the tetracarboxylic acid component and the diamine component are reacted, or after a precursor having a repeating unit represented by the general formula (I) is obtained from the tetracarboxylic acid component and the diamine component, the reaction is carried out at an appropriate temperature for an appropriate time to effect imidization to a target imidization rate. The temperature range is, for example, 0℃or higher, preferably 15℃or higher, for example, 180℃or lower, preferably 150℃or lower, and more preferably 130℃or lower. As the time range, the imidization rate can be adjusted in a shorter time as the temperature is generally higher, and the imidization rate can be adjusted in a longer time as the temperature is lower, and for example, the range of several seconds or more, for example, 1 minute or more and about 1 year or less is preferably selected appropriately. The reaction temperature and the reaction time are also preferably changed depending on the presence or absence of the addition of an imidazole compound, the type and the amount thereof, which will be described later. The one-stage feed process is preferably carried out by thermal imidization, preferably without the inclusion of a dehydrating agent for chemical imidization.

In the two-stage supply method, the tetracarboxylic acid component and the diamine component are supplied separately to a plurality of steps, and the imidization rate is adjusted by a method in which reactions are performed under different conditions in the plurality of steps. As an example illustrating the case of two-stage feeding, the following method is: in step 1, only a part of the tetracarboxylic acid component and a part of the diamine component are supplied, and the reaction is performed under the condition that the imidization reaction is suppressed after the full imidization or the precursor having a high imidization rate is obtained as a result of the high-temperature heating, in which only a part of the tetracarboxylic acid component and a part of the diamine component are supplied in step 2. The high-temperature heating condition in step 1 is preferably 100℃or higher, more preferably 120℃to 250℃and the temperature condition in step 2 is less than 100℃and more preferably less than 90 ℃. Usually at 0℃or higher, preferably at 15℃or higher. The imidization ratio can be adjusted by the ratio of the tetracarboxylic acid component to the diamine component in the 1 st step and the 2 nd step. In this process, too, it is preferably carried out in thermal imidization, preferably without a dehydrating agent for chemical imidization.

The formulae (Ib), (Ic) and (II) are repeating units of the formula (I) which are further imidized, and X in the formulae (Ib), (Ic) and (II) ₁ 、Y ₁ 、R ₁ And R is ₂ The presence of a group from formula (I). Therefore, the description of the preferred structure of the following formula (I) also applies to the structures of the formulae (Ib), (Ic) and (II).

The precursor represented by the general formula (I) is particularly preferably R ₁ And R is ₂ Polyamic acid which is a hydrogen atom. At X ₁ And Y ₁ In the case of an aliphatic group, the aliphatic group is preferably a group having an alicyclic structure.

X in all the repeating units in the polyimide precursor ₁ Preferably, 70 mol% or more is a structure represented by the following formula (1-1), that is, a structure derived from norbornane-2-spiro- α -cyclopentanone- α' -spiro-2 "-norbornane-5, 5",6 "-tetracarboxylic dianhydride (hereinafter abbreviated as CpODA as needed).

[ chemical 8]

Y in all the repeating units in the polyimide precursor ₁ Preferably, 70 mol% or more is a structure represented by the following formula (D-1) and/or (D-2), namely, a structure derived from 4,4' -diaminobenzanilide (abbreviated as DADABA, if necessary).

[ chemical 9]

By using the composition containing such a polyimide precursor, a polyimide film having excellent thermal characteristics such as a low linear thermal expansion coefficient and excellent transparency can be produced.

As polyimide precursor, X in the general formula (I) is provided ₁ And Y ₁ The monomer (tetracarboxylic acid component, diamine component, and other components) of (a) is described, and the production method is described next.

In the present specification, the tetracarboxylic acid component includes tetracarboxylic acid, tetracarboxylic dianhydride, and tetracarboxylic acid derivatives such as tetracarboxylic silyl ester, tetracarboxylic ester, and tetracarboxylic acid chloride, which are used as raw materials for producing polyimide. Although not particularly limited, the use of tetracarboxylic dianhydride in the production is simple, and in the following description, an example of the use of tetracarboxylic dianhydride as the tetracarboxylic acid component will be described. The diamine component has 2 amino groups (-NH) as a raw material for producing polyimide ₂ ) Diamine compound of (a).

In the present specification, the polyimide film refers to both a film formed on a (carrier) substrate and present in a laminate, and a film obtained by peeling off the substrate. In addition, a material obtained by heat-treating (imidizing) a polyimide precursor composition, which is a material constituting a polyimide film, may be referred to as a "polyimide material".

As described above, X is a group of all repeating units in the polyimide precursor ₁ Preferably 70 mol% or more is the structure represented by the formula (1-1), more preferably 80 mol% or more, still more preferably 90 mol% or more, and most preferably 95 mol% or more (also very preferably 100 mol%) is the structure represented by the formula (1-1). As X ₁ The tetracarboxylic dianhydride providing the structure of formula (1-1) is CpODA.

CpODA may be a mixture of stereoisomers or may be a specific 1 stereoisomer. The preferred stereoisomers are not particularly limited, and examples thereof include trans-endo-norbornane-2-spiro-alpha-cyclopentanone-alpha '-spiro-2 "-norbornane-5, 5",6 "-tetracarboxylic dianhydride (CpODA-tee) and cis-endo-norbornane-2-spiro-alpha-cyclopentanone-alpha' -spiro-2" -norbornane-5, 5", 6" -tetracarboxylic dianhydride (CpODA-cee).

[ chemical 10]

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

In the present invention, a 4-valent aliphatic group or aromatic group other than the structure represented by the formula (1-1) (simply referred to as "other X" in the following ₁ ") as X ₁ . That is, the tetracarboxylic acid component may contain other tetracarboxylic acid derivatives in an amount other than CpODA within a range that does not impair the effects of the present invention. The amount of the other tetracarboxylic acid derivative is less than 30 mol%, more preferably less than 20 mol%, still more preferably less than 10 mol% (also preferably 0 mol%) based on 100 mol% of the tetracarboxylic acid component.

In "other X ₁ In the case of "a 4-valent group having an aromatic ring", a 4-valent group having an aromatic ring having 6 to 40 carbon atoms is preferable.

Examples of the 4-valent group having an aromatic ring include the following groups.

[ chemical 11]

(wherein Z is ₁ Is a direct bond, or any of the following 2-valent groups.

[ chemical 12]

Wherein Z in the formula ₂ Is a 2-valent organic group, Z ₃ 、Z ₄ Each independently is an amide bond, an ester bond, a carbonyl bond, Z ₅ Is an organic group containing an aromatic ring. )

As Z ₂ Specifically, examples thereof include an aliphatic hydrocarbon group having 2 to 24 carbon atoms and an aromatic hydrocarbon group having 6 to 24 carbon atoms.

As Z ₅ Specifically, an aromatic hydrocarbon group having 6 to 24 carbon atoms is exemplified.

The following 4-valent group is particularly preferable as the 4-valent group having an aromatic ring because the polyimide film obtained can achieve both high heat resistance and high transparency.

[ chemical 13]

(wherein Z is ₁ Is a direct bond or a hexafluoroisopropylidene bond. )

Here, the polyimide film obtained is Z because it is compatible with high heat resistance, high transparency, and low linear thermal expansion coefficient ₁ More preferably direct bonding.

In addition, in the above formula (9), Z is preferably selected from ₁ Is of the following formula (3A):

[ chemical 14]

Compounds containing fluorenyl groups are shown. Z is Z ₁₁ And Z ₁₂ Each independently is preferably the same, a single bond or a 2-valent organic group. As Z ₁₁ And Z ₁₂ The organic group containing an aromatic ring is preferable, and a structure represented by formula (3 A1) is preferable, for example.

[ 15]

(Z ₁₃ And Z ₁₄ Are independently a single bond-COO-, -OCO-or-O-, where Z is ₁₄ In the case of bonding to fluorenyl groups, Z is preferred ₁₃ is-COO- -OCO-or-O-and Z ₁₄ Is of a single bond structure; r is R ₉₁ Is an alkyl group having 1 to 4 carbon atoms or a phenyl group, preferably a methyl group, and n is an integer of 0 to 4, preferably 1. )

As provision X ₁ Examples of the tetracarboxylic acid component having a repeating unit of the general formula (I) having a 4-valent group of an aromatic ring include 2, 2-bis (3, 4-dicarboxyphenyl) hexafluoropropane, 4- (2, 5-dioxotetrahydrofuran-3-yl) -1,2,3, 4-tetrahydronaphthalene-1, 2-dicarboxylic acid, pyromellitic acid, 3',4' -benzophenone tetracarboxylic acid, 3',4' -biphenyl tetracarboxylic acid, 2, 3',4' -biphenyltetracarboxylic acid, 4' -oxo-diphthalic acid, bis (3, 4-dicarboxyphenyl) sulfone, m-terphenyl-3, 4,3',4' -tetracarboxylic acid, p-terphenyl-3, 4,3',4' -tetracarboxylic acid, dicarboxyphenyl dimethylsilane, dicarboxyphenoxydiphenyl sulfide, sulfonyl diphthalic acid, tetracarboxylic dianhydrides thereof, tetracarboxylic silyl esters, tetracarboxylic acid chlorides, and the like. As provision X ₁ Examples of the tetracarboxylic acid component having a repeating unit of the general formula (I) having a 4-valent group of an aromatic ring containing a fluorine atom include derivatives such as 2, 2-bis (3, 4-dicarboxyphenyl) hexafluoropropane, tetracarboxylic dianhydride thereof, tetracarboxylic silyl ester, tetracarboxylic ester, and tetracarboxylic acid chloride. Further, preferable examples of the compound include (9H-fluorene-9, 9-diyl) bis (2-methyl-4, 1-phenylene) bis (1, 3-dioxo-1, 3-dihydro)Isobenzofuran-5-carboxylate). The tetracarboxylic acid component may be used alone, or two or more kinds may be used in combination.

"other X ₁ In the case of "a 4-valent group having an alicyclic structure," a 4-valent group having an alicyclic structure having 4 to 40 carbon atoms is preferable, and at least one aliphatic 4 to 12-membered ring is more preferable, and an aliphatic 4-membered ring or an aliphatic 6-membered ring is more preferable. Examples of the 4-valent group having a preferable aliphatic 4-membered ring or aliphatic 6-membered ring include the following groups.

[ 16]

(wherein R is ₃₁ ～R ₃₈ Each independently is a direct bond or a 2-valent organic group. R is R ₄₁ ～R ₄₇ And R ₇₁ ～R ₇₃ Each independently represents a member selected from the group consisting of: -CH ₂ -、-CH＝CH-、-CH ₂ CH ₂ -, -O-, -S-is one of the group consisting of. R is R ₄₈ Is an organic group containing an aromatic or alicyclic structure. )

As R ₃₁ 、R ₃₂ 、R ₃₃ 、R ₃₄ 、R ₃₅ 、R ₃₆ 、R ₃₇ 、R ₃₈ Specifically, examples thereof include a direct bond, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an oxygen atom (-O-), a sulfur atom (-S-), a carbonyl bond, an ester bond, and an amide bond.

As R ₄₈ Examples of the organic group containing an aromatic ring include the following groups.

[ chemical 17]

(wherein W is ₁ N is a direct bond or a 2-valent organic group ₁₁ ～n ₁₃ Each independently represents an integer of 0 to 4, R ₅₁ 、R ₅₂ 、R ₅₃ Each independently is a carbon atomAlkyl, halo, hydroxy, carboxyl, or trifluoromethyl having a number of 1 to 6. )

As W ₁ Specifically, a direct bond, a 2-valent group represented by the following formula (5), and a 2-valent group represented by the following formula (6) may be mentioned.

[ chemical 18]

(R in formula (6) ₆₁ ～R ₆₈ Each independently represents a direct bond or any of the 2-valent groups represented by the above formula (5). )

The following groups are particularly preferred as the 4-valent group having an alicyclic structure, since the polyimide obtained can achieve high heat resistance, high transparency, and low linear thermal expansion coefficient.

[ chemical 19]

As provision X ₁ Examples of the tetracarboxylic acid component which is a repeating unit of the formula (I) having a 4-valent group of alicyclic structure include 1,2,3, 4-cyclobutane tetracarboxylic acid, isopropylidene diphenoxydiphthalic acid, cyclohexane-1, 2,4, 5-tetracarboxylic acid, and [1,1' -bis (cyclohexane) ]-3,3', 4' -tetracarboxylic acid, [1,1' -bis (cyclohexane)]-2, 3',4' -tetracarboxylic acid, [1,1' -bis (cyclohexane)]-a reaction of 2,2',3,3' -tetracarboxylic acid, 4' -methylenebis (cyclohexane-1, 2-dicarboxylic acid), 4' - (propane-2, 2-diyl) bis (cyclohexane-1, 2-dicarboxylic acid), 4' -oxybis (cyclohexane-1, 2-dicarboxylic acid), 4' -thiobis (cyclohexane-1, 2-dicarboxylic acid) 4,4' -sulfonylbis (cyclohexane-1, 2-dicarboxylic acid), 4' - (dimethylsilanediyl) bis (cyclohexane-1, 2-dicarboxylic acid), 4' - (tetrafluoropropane-2, 2-diyl) bis (cyclohexane-1, 2-dicarboxylic acid), octahydropentalene-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]Octyl-5-Alkene-2, 3,7, 8-tetracarboxylic acid, tricyclo [4.2.2.02,5 ]]Decane-3, 4,7, 8-tetracarboxylic acid, tricyclo [4.2.2.02,5 ]]Dec-7-en-3, 4,9, 10-tetracarboxylic acid, 9-oxatricyclo [4.2.1.02,5 ]]Nonane-3, 4,7, 8-tetracarboxylic acid, (4 arH,8 ach) -decahydro-1 t,4t:5c,8 c-dimethylnaphthalene-2 c,3c,6c,7 c-tetracarboxylic acid, (4 arH,8 ach) -decahydro-1 t,4t:5c,8 c-dimethylnaphthalene-2 t,3t,6c,7 c-tetracarboxylic acid, decahydro-1, 4-ethylidene-5, 8-dimethylnaphthalene-2, 3,6, 7-tetracarboxylic acid, tetradechydro-1, 4:5,8:9, 10-trimethylanthracene-2, 3,6, 7-tetracarboxylic acid, tetracarboxylic dianhydride, silyl tetracarboxylic acid ester, tetracarboxylic acid chloride, and the like. The tetracarboxylic acid component may be used alone, or two or more kinds may be used in combination.

As described above, Y is present in all the repeating units in the polyimide precursor ₁ Preferably 70 mol% or more is a structure represented by the formula (D-1) and/or (D-2), more preferably 80 mol% or more, still more preferably 90 mol% or more (also preferably 100 mol%) is a structure represented by the formula (D-1) and/or (D-2). As Y ₁ The diamine compound having the structure of formula (D-1) or (D-2) is 4,4' -Diaminobenzanilide (DABAN).

In the present invention, the aliphatic or aromatic group having a valence of 2 other than the structures represented by the formulas (D-1) and (D-2) may be contained in an amount within a range not impairing the effects of the present invention (abbreviated as "other Y ₁ ") as Y ₁ . That is, the diamine component may contain other diamine compounds in addition to DABA in an amount within a range that does not impair the effects of the present invention. The amount of the other diamine compound is less than 30 mol%, more preferably less than 20 mol%, still more preferably less than 10 mol% (also preferably 0 mol%) based on 100 mol% of the diamine component.

"other Y ₁ In the case of "a 2-valent group having an aromatic ring", a 2-valent group having an aromatic ring having 6 to 40 carbon atoms is preferable, and a 6 to 20 carbon atoms is more preferable.

Examples of the 2-valent group having an aromatic ring include the following groups.

[ chemical 20]

(wherein W is ₁ N is a direct bond or a 2-valent organic group ₁₁ ～n ₁₃ Each independently represents an integer of 0 to 4, R ₅₁ 、R ₅₂ 、R ₅₃ Each independently represents an alkyl group having 1 to 6 carbon atoms, a halogen group, a hydroxyl group, a carboxyl group, or a trifluoromethyl group. )

[ chemical 21]

[ chemical 22]

Here, since the polyimide obtained can achieve high heat resistance, high transparency, and low linear thermal expansion coefficient, W ₁ Particularly preferred are direct bonds, or are selected from the formulae: -NHCO-, -CONH-, -COO-, -OCO-, and a member of the group shown. In addition, W ₁ Also particularly preferred is R ₆₁ ～R ₆₈ Is directly bonded or selected from the formula: -NHCO-, -CONH-, -COO-, -OCO-, and any of the above-mentioned 2-valent groups represented by the formula (6). Wherein, when-NHCO-or-CONH-is selected, "other Y" is selected in a manner different from the formula (D-1) or the formula (D-2) ₁ ”。

In addition, as preferable groups, in the above formula (4), W may be mentioned ₁ Is of the following formula (3B):

[ chemical 23]

The fluorenyl-containing group compound shown. Z is Z ₁₁ And Z ₁₂ Each independently is preferably the same, a single bond or a 2-valent organic group. As Z ₁₁ And Z ₁₂ The organic group containing an aromatic ring is preferable, and a structure represented by formula (3B 1) is preferable, for example.

[ chemical 24]

(Z ₁₃ And Z ₁₄ Are independently a single bond-COO-, -OCO-or-O-, where Z is ₁₄ In the case of bonding to fluorenyl groups, Z is preferred ₁₃ is-COO- -OCO-or-O-and Z ₁₄ Is of a single bond structure; r is R ₉₁ Is an alkyl group having 1 to 4 carbon atoms or a phenyl group, preferably a phenyl group, and n is an integer of 0 to 4, preferably 1. )

As other preferable groups, in the above formula (4), W is exemplified ₁ The compounds which are phenylene groups, that is, terphenylenediamine compounds, are particularly preferably all para-bonded.

As other preferable groups, in the above formula (4), W is exemplified ₁ R in the structure of the first 1 phenyl ring of formula (6) ₆₁ And R is ₆₂ Is a compound of 2, 2-propylene.

As another preferable group, in the above formula (4), W is exemplified ₁ A compound represented by the following formula (3B 2).

[ chemical 25]

As provision Y ₁ Examples of the diamine component having a repeating unit of the formula (I) having a 2-valent group of an aromatic ring include p-phenylenediamine and m-phenylene Diamine, benzidine, 3 '-diaminobiphenyl, 2' -bis (trifluoromethyl) benzidine, 3 '-bis (trifluoromethyl) benzidine, m-benzidine, 3,4' -diaminobenzidine, N '-bis (4-aminophenyl) terephthalamide, N' -p-phenylenebis (p-aminobenzamide), 4-aminophenoxy-4-diaminobenzoate, bis (4-aminophenyl) terephthalate, biphenyl-4, 4 '-dicarboxylic acid bis (4-aminophenyl) ester, p-phenylenebis (p-aminobenzoate), bis (4-aminophenyl) - [1,1' -biphenyl]-4,4 '-dicarboxylic acid ester, [1,1' -biphenyl ]]-4,4 '-diylbis (4-aminobenzoate), 4' -oxydiphenylamine, 3 '-oxydiphenylamine, p-methylenebis (phenylenediamine), 1, 3-bis (4-aminophenoxy) benzene, 1, 3-bis (3-aminophenoxy) benzene 1, 4-bis (4-aminophenoxy) benzene, 4' -bis (4-aminophenoxy) biphenyl, 4 '-bis (3-aminophenoxy) biphenyl, 2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane, 2-bis (4-aminophenyl) hexafluoropropane, bis (4-aminophenyl) sulfone, and 3,3' -bis (trifluoromethyl) benzidine, 3 '-bis ((aminophenoxy) phenyl) propane, 2' -bis (3-amino-4-hydroxyphenyl) hexafluoropropane, bis (4- (4-aminophenoxy) diphenyl) sulfone, bis (4- (3-aminophenoxy) diphenyl) sulfone, octafluorobiphenyl, 3 '-dimethoxy-4, 4' -diaminobiphenyl, 3 '-dichloro-4, 4' -diaminobiphenyl, 3 '-difluoro-4, 4' -diaminobiphenyl, 2, 4-bis (4-aminophenylamino) -6-amino-1, 3, 5-triazine, 2, 4-bis (4-aminoanilino) -6-methylamino-1, 3, 5-triazine, 2, 4-bis (4-aminoanilino) -6-ethylamino-1, 3, 5-triazine, 2, 4-bis (4-aminoanilino) -6-anilino-1, 3, 5-triazine. As provision Y ₁ Examples of the diamine component having a repeating unit of the formula (I) having a 2-valent group of an aromatic ring containing a fluorine atom include 2,2 '-bis (trifluoromethyl) benzidine, 3' -bis (trifluoromethyl) benzidine, and 2, 2-bis [4- (4-aminophenoxy) phenyl group]Hexafluoropropane, 2-bis (4-aminophenyl) hexafluoropropane, 2' -bis (3-amino-4-hydroxyphenyl) hexafluoropropane. Further, preferable diamine compounds include 9, 9-bis (4-aminophenyl) fluorene and 4,4'- ((9H-fluorene-9, 9-diyl) bis ([ 1,1' -biphenyl)]-5, 2-diyl) bis (oxy)) diamine, [1,1':4',1 "-terphenyl ]]-4,4”-diamines, 4'- ([ 1,1' -binaphthyl)]-2,2' -diylbis (oxy)) diamine. The diamine component may be used alone, or two or more kinds may be used in combination.

"other Y ₁ In the case of "a 2-valent group having an alicyclic structure," a 2-valent group having an alicyclic structure having 4 to 40 carbon atoms is preferable, and at least one aliphatic 4 to 12-membered ring is more preferable, and an aliphatic 6-membered ring is still more preferable.

Examples of the 2-valent group having an alicyclic structure include the following groups.

[ chemical 26]

(wherein V ₁ 、V ₂ Each independently is a direct bond or a 2-valent organic group, n ₂₁ ～n ₂₆ Each independently represents an integer of 0 to 4, R ₈₁ ～R ₈₆ Each independently is an alkyl group having 1 to 6 carbon atoms, a halogen group, a hydroxyl group, a carboxyl group, or a trifluoromethyl group, R ₉₁ 、R ₉₂ 、R ₉₃ Each independently is selected from the formula: -CH ₂ -、-CH＝CH-、-CH ₂ CH ₂ -, -O-, -S-is one of the group consisting of. )

As V ₁ 、V ₂ Specifically, a direct bond and a 2-valent group represented by the above formula (5) may be mentioned.

The following groups are particularly preferred as the 2-valent group having an alicyclic structure, since the polyimide obtained can achieve both high heat resistance and low linear thermal expansion coefficient.

[ chemical 27]

As the 2-valent group having an alicyclic structure, the following groups are preferable.

[ chemical 28]

As provision Y ₁ Examples of the diamine component having a repeating unit of the general formula (I) having a 2-valent group of alicyclic structure include 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-sec-butylcyclohexane, 1, 4-diamino-2-tert-butylcyclohexane, 1, 2-diaminocyclohexane, 1, 3-diaminocyclobutane, 1, 4-bis (aminomethyl) cyclohexane, 1, 3-bis (aminomethyl) cyclohexane, diaminobicycloheptane, diaminomethoxy bicycloheptane, isophorone diamine, diaminotricyclodecane, diaminomethyltricyclodecane, bis (aminocyclohexyl) methane, bis (3 ' -amino-cyclohexyl) 3, 6' -bis (3, 3' -spirotetramino) -3, 3' -bis (3 ', 6' -spirotetramino-3, 3' -spirotetramino-3 ' -3-4-spirotetramino-3 ' -spirone. The diamine component may be used alone, or two or more kinds may be used in combination.

As the tetracarboxylic acid component and the diamine component which provide the repeating unit represented by the above general formula (I), any of aliphatic tetracarboxylic acids other than alicyclic (in particular, dianhydride) and/or aliphatic diamines may be used, and the content thereof is preferably less than 30 mol%, more preferably less than 20 mol%, still more preferably less than 10 mol% (including 0%) with respect to 100 mol% of the total of the tetracarboxylic acid component and the diamine component.

As "other Y ₁ "the transparency of the polyimide film obtained may be improved by containing a diamine compound having a structure represented by the formula (4), specifically containing p-phenylenediamine, 3 '-bis (trifluoromethyl) benzidine, m-tolidine, 4' -bis (4-aminophenoxy) biphenyl, or the like. In addition, as "other Y ₁ "by containing the structure represented by the formula (3B) as a specific compound by containing 9, 9-bis (4-aminobenzene)A group) fluorene, and the like, and can sometimes increase Tg and reduce the retardation (retardation) in the film thickness direction.

The polyimide precursor can be produced from the above-described tetracarboxylic acid component and diamine component. According to R ₁ And R is ₂ The chemical structure taken out, the polyimide precursor used in the present invention (polyimide precursor comprising at least one of the repeating units represented by the above formula (I)) can be classified into:

1) Polyamic acid (R) ₁ And R is ₂ Is hydrogen; an alias polyamic acid);

2) Polyamic acid ester (R) ₁ And R is ₂ At least a portion of which is an alkyl group; an alias polyamic acid ester);

3) 4) Polyamic acid silyl ester (R) ₁ And R is ₂ At least a portion of (a) is an alkylsilyl group; alias polyamide acid silyl ester).

The polyimide precursor can be easily produced by the following production method according to the classification. However, the method for producing the polyimide precursor used in the present invention is not limited to the following production method.

1) Polyamic acid

In the case where the repeating unit represented by the formula (I) is a polyamic acid, any one of the following methods can be employed: a one-stage supply method in which imidization is performed intramolecularly (or randomly); and a multistage supply method in which the tetracarboxylic acid component and the diamine component are supplied separately and only between a part of the tetracarboxylic acid component and a part of the diamine component (or in blocks) in the imidization reaction.

An example of the production of a polyimide precursor by the one-stage supply method will be described. The tetracarboxylic dianhydride and the diamine component as the tetracarboxylic acid component are reacted in a solvent at a ratio of substantially equimolar, preferably a molar ratio of the diamine component to the tetracarboxylic acid component [ the number of moles of the diamine component/the number of moles of the tetracarboxylic acid component ] of preferably 0.90 to 1.10, more preferably 0.95 to 1.05, at a relatively low temperature of, for example, 120 ℃ or lower, while suppressing excessive imidization. More specifically, the diamine is dissolved in an organic solvent or water, and the tetracarboxylic dianhydride is slowly added to the solution while stirring, and stirred at a temperature ranging from 0 to 120 ℃, preferably from 5 to 80 ℃ for 1 to 72 hours. Further, if necessary, the reaction mixture may be stored at 5 to 40℃for a predetermined period of time, for example, about 1 day to 1 year, and imidized to adjust the imidization rate. The order of addition of the diamine and the tetracarboxylic dianhydride is preferable because it is easy to increase the molecular weight of the polyimide precursor. The order of addition of the diamine and the tetracarboxylic dianhydride in the above production method may be reversed, and it is preferable to reduce the amount of precipitate. When water is used as the solvent, an imidazole such as 1, 2-dimethylimidazole or a base such as triethylamine is preferably added in an amount of 0.8 times or more equivalent to the carboxyl group of the polyamide acid (polyimide precursor) to be produced.

When the reaction between the tetracarboxylic acid component and the diamine component is carried out at a relatively high temperature, for example, at 80℃or higher, 90℃or higher, or 100℃or higher, the target imidization rate can be achieved in a relatively short period of time while suppressing excessive imidization, and thus the polyimide precursor composition of the present invention can be used as it is.

On the other hand, the temperature (heating) stage (stage) of the reaction may be divided into 2 stages. In one embodiment, the reaction of the tetracarboxylic acid component and the diamine component is carried out at a relatively low temperature (for example, at 0 ℃ or higher, for example, 80 ℃ or lower, and further 70 ℃ or lower) to obtain a polyimide precursor having a low imidization rate (including an imidization rate of 0%), and the polyimide precursor is heated at a relatively high temperature (for example, 80 ℃ or higher, preferably 90 ℃ or higher, and more preferably 100 ℃ or higher, for example, for 5 minutes to 72 hours) in the 2 nd stage, whereby the target imidization rate can be achieved while suppressing excessive imidization. In various embodiments, the imidization may be adjusted by performing the reaction of the tetracarboxylic acid component and the diamine component at a relatively low temperature (for example, at 0 ℃ or higher, for example, 80 ℃ or lower, and further, 70 ℃ or lower) in the 1 st stage to obtain a polyimide precursor having a low imidization rate (including an imidization rate of 0%), and further, performing imidization at a relatively low temperature (for example, at 0 ℃ or higher, 80 ℃ or lower (or less than 80 ℃) and preferably, at 70 ℃ or lower for a predetermined period of time, for example, about 1 day to 1 year in the 2 nd stage. If the temperature (heating) stage of the reaction is divided into two stages, in the 1 st stage, by conducting the reaction of the tetracarboxylic acid component and the diamine component at a lower temperature, a stable polymerization reaction can be conducted, which is advantageous in this regard.

Next, an example of the production of a polyimide precursor by the multistage supply method will be described with reference to two-stage supply. First, in step 1, a tetracarboxylic dianhydride as a tetracarboxylic acid component is reacted with a diamine component under the condition that imidization reaction is performed, specifically, for example, at a temperature of 100 ℃ or higher. More specifically, a diamine is dissolved in a solvent, and a tetracarboxylic dianhydride is slowly added to the solution while stirring, and the solution is stirred at 100℃or higher, preferably in the range of 120 to 250℃for 0.5 to 72 hours, thereby obtaining a soluble imide compound. The order of addition of the diamine and tetracarboxylic dianhydride may also be reversed.

The polymerization degree of the imide compound can be determined so as to be soluble by the molar ratio of the tetracarboxylic acid component to the diamine component to be reacted. The soluble imide compound may have an acid anhydride group or a carboxyl group at both ends, or may have an amino group.

Imidization is performed by thermal imidization, and thus a chemical imidizing agent is not used. The chemical imidizing agent herein refers to an acid anhydride such as acetic anhydride (dehydrating agent) and an amine compound such as pyridine and isoquinoline (catalyst).

Next, in step 2, a tetracarboxylic acid component and/or a diamine component is added to the reaction solution containing the soluble imide compound obtained in step 1, and the reaction is carried out to obtain the polyimide precursor of the present invention. In step 2, the tetracarboxylic acid component and/or the diamine component is/are added so that the molar ratio of the total amount of the tetracarboxylic acid component and the total amount of the diamine component, which are reacted in step 1 and step 2, is substantially equimolar, preferably so that the molar ratio of the diamine component to the tetracarboxylic acid component [ the number of moles of diamine component/the number of moles of tetracarboxylic acid component ] is 0.90 to 1.10, more preferably 0.95 to 1.05.

In step 2, the reaction is carried out under conditions that inhibit imidization, specifically at a temperature of less than 100 ℃. More specifically, the polyimide precursor of the present invention is obtained by adding a diamine to the reaction solution containing the soluble imide compound obtained in the step 1, stirring the mixture at a temperature of less than 100 ℃, preferably in the range of-20 to 80 ℃ for 1 to 72 hours, then adding a tetracarboxylic dianhydride, and stirring the mixture at a temperature of less than 100 ℃, preferably in the range of-20 to 80 ℃ for 1 to 72 hours. The order of addition of the diamine and the tetracarboxylic dianhydride may be reversed, and the diamine and the tetracarboxylic dianhydride may be simultaneously added. When the total amount of the reacted tetracarboxylic acid component is added to the solvent in step 1, only diamine is added, and when the total amount of the reacted diamine component is added to the solvent in step 1, only tetracarboxylic dianhydride is added.

Although the imidization may be performed in the step 2, the reaction temperature and the reaction time may be appropriately selected so that the imidization ratio of the polyimide precursor to be finally obtained falls within a predetermined range. Thus, the imidization rate can be adjusted by mainly producing the repeating unit of the imide structure (structure of the general formula (II)) in the step 1 and mainly producing the repeating unit of the amic acid structure represented by the above chemical formula (I) in the step 2.

2) Polyamic acid esters

When the repeating unit represented by the formula (I) is a polyamic acid ester, the repeating unit is obtained by the following reaction. First, a tetracarboxylic dianhydride is reacted with an arbitrary alcohol to obtain a dicarboxylic acid diester, and then reacted with a chlorinating agent (thionyl chloride, oxalyl chloride, etc.) to obtain a diester dicarboxylic acid chloride. The diester dicarboxylic acid chloride and diamine are stirred at a temperature in the range of-20 to 120 ℃, preferably-5 to 80 ℃ for 1 to 72 hours, thereby obtaining a polyimide precursor (polyamic acid ester). In the case of a reaction at 80 ℃ or higher, the molecular weight varies depending on the temperature history during polymerization, and imidization is performed by heat, so that there is a possibility that a polyimide precursor cannot be stably produced. Further, a polyimide precursor can be easily obtained by dehydrating condensation of a dicarboxylic acid diester and a diamine using a phosphorus-based condensing agent, a carbodiimide condensing agent, or the like.

The polyimide precursor obtained by this method is stable, and therefore, can be purified by adding a solvent such as water or alcohol for reprecipitation.

The obtained polyimide precursor (polyamic acid ester) can be reacted in the same manner as in the case of 1) polyamic acid (see the one-stage supply method, i.e., stage 2, which is one of stage 1 low temperature to stage 2 high temperature and stage 1 low temperature to stage 2 low temperature). That is, in one embodiment, the target imidization rate can be achieved while suppressing the excessive imidization reaction by heating at a relatively high temperature, for example, 80 ℃ or higher, preferably 90 ℃ or higher, more preferably 100 ℃ or higher, for example, for 5 minutes to 72 hours. In another embodiment, imidization may be performed at a relatively low temperature, for example, 0 ℃ to 80 ℃ (or less than 80 ℃), preferably 70 ℃ or less, for a predetermined period of time, for example, about 1 day to 1 year, to adjust the imidization rate.

3) Polyamic acid silyl ester (indirect method)

In the case where the repeating unit represented by the formula (I) is a polyamic acid silyl ester, the repeating unit is obtained by the reaction of the indirect method described in the present item or the direct method described in the following item. First, in the indirect method, a diamine is reacted with a silylating agent in advance to obtain a silylated diamine. Purification of the silylated diamine is carried out by distillation or the like as needed. Then, the silylated diamine is dissolved in the dehydrated solvent in advance, and the tetracarboxylic dianhydride is slowly added while stirring, and stirred at a temperature ranging from 0 to 120 ℃, preferably from 5 to 80 ℃ for 1 to 72 hours, thereby obtaining a polyimide precursor. In the case of a reaction at 80 ℃ or higher, the molecular weight varies depending on the temperature history during polymerization, and imidization is performed by heat, so that there is a possibility that a polyimide precursor cannot be stably produced.

The obtained polyimide precursor (polyamic acid silyl ester) can be reacted in the same manner as in the case of 1) polyamic acid (see the one-stage supply method, i.e., stage 2, which is one of stage 1 low temperature to stage 2 high temperature and stage 1 low temperature to stage 2 low temperature). That is, in one embodiment, the target imidization rate can be achieved while suppressing the excessive imidization reaction by heating at a relatively high temperature, for example, 80 ℃ or higher, preferably 90 ℃ or higher, more preferably 100 ℃ or higher, for example, for 5 minutes to 72 hours. In another embodiment, imidization may be performed at a relatively low temperature, for example, 0 ℃ to 80 ℃ (or less than 80 ℃), preferably 70 ℃ or less, for a predetermined period of time, for example, about 1 day to 1 year, to adjust the imidization rate.

4) Polyamic acid silyl ester (direct method)

The polyamic acid solution having a prescribed imidization rate obtained in the method of 1) is mixed with a silylating agent and stirred at a temperature ranging from 0 to 120 ℃, preferably from 5 to 80 ℃ for 1 to 72 hours, thereby obtaining a polyamic acid silyl ester having a prescribed imidization rate.

Alternatively, the step 1 is a step when the heating stage is divided into 2 steps in a one-stage supply method of obtaining a polyamic acid (see 1) having a low imidization rate by reacting a tetracarboxylic dianhydride as a tetracarboxylic acid component with a diamine component at a temperature of, for example, less than 100 ℃ under a condition that imidization of the tetracarboxylic dianhydride and the diamine component is suppressed. ). The polyamic acid solution obtained is mixed with a silylating agent and stirred at a temperature ranging from 0 to 120 ℃, preferably from 5 to 80 ℃ for 1 to 72 hours, thereby obtaining a polyamic acid silyl ester having a low imidization rate. The obtained polyimide precursor (polyamic acid silyl ester) is reacted in the same manner as in the case of the 3) polyamic acid silyl ester (indirect method), whereby the target imidization rate can be achieved.

The silylating agent used in the method of 3) and the method of 4) is preferably a chlorine-free silylating agent because it is not necessary to purify the silylated polyamic acid or the polyimide obtained. Examples of the silylating agent containing no chlorine atom include N, O-bis (trimethylsilyl) trifluoroacetamide, N, O-bis (trimethylsilyl) acetamide and hexamethyldisilazane. N, O-bis (trimethylsilyl) acetamide and hexamethyldisilazane are particularly preferable for the reason of no fluorine atom and low cost.

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

The solvent used in the preparation of the polyimide precursor is preferably water, or an aprotic solvent such as N, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, dimethylsulfoxide, or the like, and any kind of solvent may be used without any problem as long as it can dissolve the raw material monomer components and the polyimide precursor to be produced, and therefore the structure thereof is not particularly limited. As the solvent, water, or an amide solvent such as N, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, N-ethyl-2-pyrrolidone, a cyclic ester solvent such as gamma-butyrolactone, gamma-valerolactone, delta-valerolactone, gamma-caprolactone, epsilon-caprolactone, alpha-methyl-gamma-butyrolactone, a carbonate solvent such as ethylene carbonate, propylene carbonate, a glycol solvent such as triethylene glycol, a phenol solvent such as m-cresol, p-cresol, 3-chlorophenol, 4-chlorophenol, acetophenone, 1, 3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide, and the like are preferably used. In addition, other general organic solvents, that is, 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 dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, turpentine, mineral spirits, naphtha-based solvents, and the like may also be used. It should be noted that two or more solvents may be used in combination.

In the production of the polyimide precursor, the monomer and the solvent are charged and reacted at a concentration of, for example, 5 to 45 mass% in terms of the polyimide solid content concentration (polyimide equivalent mass concentration) of the polyimide precursor, without any particular limitation.

The logarithmic viscosity of the polyimide precursor is not particularly limited, but the logarithmic viscosity in an N, N-dimethylacetamide solution having a concentration of 0.5g/dL at 30℃is preferably 0.2dL/g or more, more preferably 0.3dL/g or more, particularly preferably 0.4dL/g or more. When the logarithmic viscosity is 0.2dL/g or more, the molecular weight of the polyimide precursor is high, and the obtained polyimide is excellent in mechanical strength and heat resistance.

< preferred additive >

The polyimide precursor composition may contain an imidazole compound. Although the addition of the imidazole compound may have an effect of improving the light transmittance and/or reducing the linear thermal expansion coefficient, the imidization rate may be easily increased depending on the selection of the compound. Therefore, in the case of adding an imidazole compound, it is preferable to appropriately select a compound and/or appropriately adjust the imidization rate.

The imidazole compound is not particularly limited, and examples thereof include 1, 2-dimethylimidazole, 1-methylimidazole, 2-phenylimidazole, imidazole, benzimidazole, and the like. For the reason of stability of the polyimide precursor composition, at least one imidazole compound selected from 2-phenylimidazole and benzimidazole is preferably used.

The content of the imidazole compound in the polyimide precursor composition may be appropriately selected in consideration of the balance between the addition effect and the stability of the polyimide precursor composition. The amount of the imidazole compound is preferably more than 0.01 mole and less than 1 mole relative to 1 mole of the repeating unit of the polyimide precursor. By adding the imidazole compound, mechanical properties such as elongation at break are generally improved. On the other hand, if the content of the imidazole compound is too large, the storage stability of the polyimide precursor composition may be deteriorated.

The content of the imidazole compound is more preferably 0.02 mol or more, still more preferably 0.025 mol or more, still more preferably 0.05 mol or more, and still more preferably 0.8 mol or less, still more preferably 0.6 mol or less, still more preferably 0.4 mol or less, still more preferably less than 0.4 mol, and most preferably 0.3 mol or less, per 1 mol of the repeating unit.

Patent document 6 (international publication No. 2015/080158) describes a polyimide precursor composition containing an imidazole compound, but relates to a polyimide precursor containing 2-phenylimidazole and/or benzimidazoleThe storage stability of the bulk composition is excellent and is not disclosed. In addition, the examples of this document show a decrease in light transmittance at 400nm of polyimide films made from compositions containing 2-phenylimidazole or benzimidazole compared to 1, 2-dimethylimidazole, 1-methylimidazole and 2-methylimidazole. On the other hand, the polyimide precursor (X) ₁ More than 70 mole% of the catalyst is derived from CpODA, Y ₁ More than 70 mole% from DABAN) of a polyimide film produced from a composition in which 2-phenylimidazole and/or benzimidazole is combined, the transparency is improved, and the 400nm light transmittance equal to or higher than that of 2-methylimidazole is obtained contrary to the disclosure of patent document 6. In addition, it was confirmed that 2-phenylimidazole and benzimidazole have an effect on the decrease in linear expansion coefficient as compared with other imidazoles.

< compounding of polyimide precursor composition >

The polyimide precursor composition used in the present invention contains at least one polyimide precursor and a solvent, and may further optionally contain at least one of the above-mentioned imidazole compounds.

As the solvent, the above-described solvents described as solvents used in the preparation of polyimide precursor can be used. In general, the solvent used for preparing the polyimide precursor, that is, the polyimide precursor solution, may be used as it is, but may be diluted or concentrated as needed. The imidazole compound is dissolved in the polyimide precursor composition. The concentration of the polyimide precursor is not particularly limited, but is usually 5 to 45 mass% in terms of the mass concentration (solid content concentration) of the polyimide. The polyimide equivalent mass herein refers to the mass when all the repeating units are fully imidized.

The viscosity (rotational viscosity) of the polyimide precursor of the present invention is not particularly limited, and the polyimide precursor is subjected to a shearing speed of 20sec at a temperature of 25℃using an E-type rotational viscometer ^-1 The rotational viscosity measured under the conditions of (a) is preferably 0.01 to 1000 Pa-sec, more preferably 0.1 to 100 Pa-sec. In addition, thixotropic properties may be imparted as needed. At a viscosity in the above range, the film can be easily handled when being coated or formed, and shrinkage cavity is suppressed and leveledExcellent in the property, and thus a good coating film can be obtained.

The polyimide precursor composition of the present invention may contain, as necessary, an antioxidant, an ultraviolet absorber, a filler (inorganic particles such as silica), a dye, a pigment, a coupling agent such as a silane coupling agent, a primer, a flame retardant, a defoaming agent, a leveling agent, a rheology control agent (flow aid), and the like. The polyimide precursor composition of the present invention preferably does not contain a chemical imidizing agent.

Further, according to the studies of the present inventors, it was confirmed that when a polyimide precursor composition containing a specific siloxane compound was used, warpage of the polyimide film/glass substrate laminate produced was reduced. In the present invention, a silicone compound of a type that does not impair transparency may be added to the polyimide precursor composition in an appropriate amount, or the silicone compound may be completely absent.

As for the preparation of the polyimide precursor composition, it can be prepared by adding an imidazole compound or a solution of an imidazole compound to the polyimide precursor solution obtained by the above method and mixing. The tetracarboxylic acid component and the diamine component may be reacted in the presence of an imidazole compound.

Use of polyimide precursor composition and film Properties

By further advancing imidization of the polyimide precursor of the present invention, a polyimide can be produced. In the present invention, there is no particular limitation, and any known imidization method can be suitably applied. The polyimide thus obtained may be in the form of a film, a laminate of a polyimide film and another substrate, a coating film, a powder, beads, a molded article, a foam, or the like.

The thickness of the polyimide film is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 5 μm or more, for example, 250 μm or less, preferably 150 μm or less, still more preferably 100 μm or less, still more preferably 50 μm or less, depending on the application.

In one embodiment of the present invention, the polyimide film preferably has a 400nm light transmittance of 79% or more, more preferably 80% or more, as measured with a film having a thickness of 10. Mu.m. The polyimide film preferably has a Yellowness (YI) of 3.2 or less, more preferably 3.0 or less, and most preferably 2.7 or less, as measured with a film having a thickness of 10. Mu.m.

The polymeric films of the present invention have extremely low coefficients of linear thermal expansion. In one embodiment of the present invention, the polyimide film preferably has a coefficient of linear thermal expansion (CTE) of 20ppm/K or less, more preferably less than 20ppm, and most preferably 15ppm/K or less from 150 ℃ to 250 ℃ as measured with a film having a thickness of 10 μm.

The polymeric film of the present invention has extremely high heat resistance. In one embodiment of the present invention, the polyimide has a 5% weight loss temperature of preferably 500 ℃ or higher, more preferably 505 ℃ or higher, and still more preferably 510 ℃ or higher. In the case of forming a gas barrier film or the like on polyimide by forming a transistor or the like on polyimide, if the heat resistance is low, there is a case where expansion occurs between polyimide and the gas barrier film due to outgas accompanying decomposition of polyimide or the like. In general, the heat resistance is preferably high, but depending on the application, characteristics other than heat resistance may be required, and the 5% weight loss temperature may be 500 ℃ or less.

In one embodiment of the present invention, the polyimide film preferably has an elongation at break of 10% or more, the film having a thickness of 10 μm.

In another preferred embodiment of the present invention, the breaking strength of the polyimide film is preferably 150MPa or more, more preferably 170MPa or more, still more preferably 180MPa or more, still more preferably 200MPa or more, still more preferably 210MPa or more. The breaking strength may be, for example, a value obtained from a film having a film thickness of about 5 to 100. Mu.m.

It is particularly preferable to satisfy the above-mentioned preferable characteristics concerning the polyimide film at the same time.

The polyimide film can be produced by a known method. Representative methods are the following: the polyimide precursor composition is cast coated onto a substrate, and thereafter, heat imidization is performed on the substrate to obtain a polyimide film. This method is described below in connection with the production of a polyimide film/substrate laminate. Alternatively, the polyimide precursor composition may be cast onto a substrate, dried by heating, and then the self-supporting film may be produced, and the self-supporting film may be peeled off from the substrate, for example, by holding the film with a tenter, and then the film may be subjected to thermal imidization in a state where the film can be degassed from both sides thereof, to obtain a polyimide film.

Polyimide film/substrate laminate and method for producing flexible electronic device

The polyimide film/substrate laminate of the present invention can be produced by the following steps: (a) A step of applying the polyimide precursor composition to a substrate; (b) The polyimide precursor is heat-treated on the substrate to produce a laminate (polyimide film/substrate laminate) in which a polyimide film is laminated on the substrate. The method for producing a flexible electronic device according to the present invention uses the polyimide film/substrate laminate produced in the steps (a) and (b), and further includes the steps of: namely, (c) forming at least one layer selected from the group consisting of a conductor layer and a semiconductor layer on the polyimide film of the laminate; and (d) a step of peeling off 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 and a solvent. The polyimide precursor may be used as the material described in the item of the polyimide precursor composition. The polyimide precursor described as a preferable material in the item of the polyimide precursor composition is also preferable in the method of the present invention, and is not particularly limited.

First, in the step (a), a polyimide precursor composition is cast onto a substrate, and imidized and desolvated by a heat treatment to form a polyimide film, thereby obtaining a laminate of the substrate and the polyimide film (polyimide film/substrate laminate).

As the base material, a heat-resistant material is used, for example, a plate-like or sheet-like base material of a ceramic material (glass, alumina, or the like), a metal material (iron, stainless steel, copper, aluminum, or the like), a semiconductor material (silicon, a compound semiconductor, or the like), or a film or sheet-like base material of a heat-resistant plastic material (polyimide, or the like) or the like is used. In general, a flat and smooth plate-like shape is preferable, and in general, a glass substrate such as soda lime glass, borosilicate glass, alkali-free glass, or sapphire glass is used; a semiconductor (including a compound semiconductor) substrate of silicon, gaAs, inP, gaN, or the like; metal substrates of iron, stainless steel, copper, aluminum, and the like.

In the present invention, a glass substrate is particularly preferable. Glass substrates have been developed which are planar, smooth and large-area, and can be readily obtained. In particular, as the area of the substrate increases, warpage becomes remarkable, and glass substrates are relatively likely to warp from the viewpoint of rigidity, and therefore, by applying the present invention, the problems when using glass substrates can be solved. The thickness of the plate-like base material such as a glass substrate is not limited, but is, for example, 20 μm to 4mm, preferably 100 μm to 2mm, in view of ease of handling. The size of the plate-like substrate is not particularly limited, and one side (long side in the case of rectangle) is, for example, about 100mm to 4000mm, preferably about 200mm to 3000mm, and more preferably about 300mm to 2500 mm.

The substrate such as a glass substrate may have an inorganic thin film (for example, a silicon oxide film) or a resin thin film formed on the surface thereof.

The method of casting the polyimide precursor composition on the substrate is not particularly limited, and examples thereof include conventionally known methods such as a slit coating method, a die coating method, a blade coating method, a spray coating method, an inkjet coating method, a nozzle coating method, a spin coating method, a screen printing method, a bar coating method, and an electrodeposition method.

In the step (b), the polyimide precursor composition is subjected to a heat treatment on the substrate and converted into a polyimide film, thereby obtaining a polyimide film/substrate laminate. The heating conditions are not particularly limited, and it is preferable to dry the material at a temperature ranging from 50 to 150℃and then to treat the material at a maximum heating temperature ranging from 150 to 600℃and preferably from 200 to 550℃and more preferably from 250 to 500 ℃. The heating conditions in the case of using the polyimide solution are not particularly limited, and the maximum heating temperature is, for example, 100 to 600 ℃, preferably 150 ℃ or higher, more preferably 200 ℃ or higher, and preferably 500 ℃ or lower, more preferably 450 ℃ 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. If the thickness is less than 1 μm, the polyimide film may not maintain sufficient mechanical strength, and may not be completely stressed and broken when used as a flexible electronic device substrate, for example. 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 increased, the thickness of the flexible device may be difficult to thin. In order to maintain sufficient resistance as a flexible device and further thin the polyimide film, the thickness of the polyimide film is preferably 2 to 50 μm.

It is particularly preferable to satisfy the above preferable characteristics concerning the polyimide film and the laminate at the same time.

The polyimide film in the polyimide film/base material laminate may have a 2 nd layer such as a resin film or an inorganic film on the surface. That is, after forming a polyimide film on a base material, the 2 nd layer may be laminated to form a flexible electronic device substrate. It is preferable to have at least an inorganic film, and particularly preferable to function as a barrier layer for water vapor, oxygen (air), or the like. The water vapor barrier layer may be, for example, a layer containing a material selected from the group consisting of silicon nitride (SiN _x ) Silicon oxide (SiO) _x ) Silicon oxynitride (SiO) _x N _y ) Alumina (Al) ₂ O ₃ ) Titanium oxide (TiO) ₂ ) Zirconium oxide (ZrO) ₂ ) And an inorganic film of an inorganic substance selected from the group consisting of metal oxides, metal nitrides and metal oxynitrides. Generally, as a film forming method of these thin films, a physical vapor deposition method such as a vacuum vapor deposition method, a sputtering method, or ion plating, a plasma CVD method, or a catalytic chemical vapor deposition method is known And chemical vapor deposition (chemical vapor deposition) such as Cat-CVD. The layer 2 may be a plurality of layers.

In the case where the 2 nd layer is a plurality of layers, the resin film and the inorganic film may be combined, and examples of the 3-layer structure include a barrier layer/polyimide layer/barrier layer formed on a polyimide film in a polyimide film/base material laminate.

In the step (c), at least one layer selected from the conductor layer and the semiconductor layer is formed on the polyimide film (including the case where the 2 nd layer such as an inorganic film is laminated on the surface of the polyimide film) using the polyimide/base material laminate obtained in the step (b). These layers may be directly formed on the polyimide film (including the case where the 2 nd layer is laminated), or may be formed indirectly after other layers necessary for the device are laminated.

The conductor layer and/or the semiconductor layer the appropriate conductor layer and (inorganic, organic) semiconductor layer are selected according to the elements and circuits required for the target electronic device. In the step (c) of the present invention, when at least one of the conductor layer and the semiconductor layer is formed, it is preferable that at least one of the conductor layer and the semiconductor layer is formed on the polyimide film on which the inorganic film is formed.

The conductor layer and the semiconductor layer include both of the case of being formed on the entire surface of the polyimide film and the case of being formed on a part of the polyimide film. The present invention may be transferred to the step (d) immediately after the step (c), or may be transferred to the step (d) after forming at least one layer selected from the conductor layer and the semiconductor layer in the step (c) and then further forming the device structure.

In the case of manufacturing a TFT liquid crystal display device as a flexible device, for example, a metal wiring, a TFT using amorphous silicon or polysilicon, a transparent pixel electrode, or the like is formed on a polyimide film having an inorganic film formed on the entire surface as needed. The TFT includes, for example, a semiconductor layer such as a gate metal layer or an amorphous silicon film, a gate insulating layer, wirings connected to pixel electrodes, and the like. In addition, the structure required for the liquid crystal display can be further formed by a known method. In addition, a transparent electrode and a color filter may be formed on the polyimide film.

In the case of manufacturing an organic EL display, for example, a TFT may be formed as needed on a polyimide film in which an inorganic film is formed over the entire surface as needed, for example, in addition to a transparent electrode, a light-emitting layer, a hole-transporting layer, an electron-transporting layer, and the like.

The polyimide film preferred in the present invention is excellent in various properties such as heat resistance and toughness, and thus a method for forming a circuit, an element, and other structures required for a device is not particularly limited.

Next, in the step (d), the base material and the polyimide film are peeled off. The peeling method may be a mechanical peeling method in which peeling is performed physically by applying an external force, or a so-called laser peeling method in which peeling is performed by irradiating a laser beam from a substrate surface.

The device is completed by further forming or assembling a structure or a component required for the device in a (semi) product having the polyimide film after peeling the substrate as a substrate.

Examples

The present invention will be further illustrated by the following examples and comparative examples. The present invention is not limited to the following examples.

In the following examples, the evaluation was performed by the following methods.

< evaluation of polyimide precursor solution (varnish) >)

[ imidization Rate ]

The solvent is dimethyl sulfoxide-d ₆ Polyimide precursor solution was prepared by Japanese electronic system M-AL400 ¹ The imidization ratio [ content of repeating units represented by chemical formula (2) relative to the total repeating units ] is calculated from the ratio of the integral value of the peak of aromatic proton to the integral value of the peak of carboxylic acid proton by H-NMR measurement ]。

Imidization ratio (%) = { X- (Y/Z). Times.A }/2X 100 (I)

X: integral value of amide proton peak at imidization ratio of 0% obtained from input amount of monomer

Y: from the following components ¹ Integral value of amide proton peak obtained by H-NMR measurement

Z: from the following components ¹ Integral value of aromatic proton peak obtained by H-NMR measurement

A: integral value of aromatic proton peak obtained from monomer input

< evaluation of polyimide film >

[ light transmittance at 400nm ]

The transmittance of a polyimide film having a film thickness of about 10 μm at 400nm was measured using an ultraviolet-visible spectrophotometer/V-650 DS (manufactured by Japan spectroscopy).

[ Yellowness (YI) ]

YI of the polyimide film was measured according to the standard of ASTEM E313 using an ultraviolet-visible spectrophotometer/V-650 DS (manufactured by Japan spectroscopy). The light source was D65 and the angle of view was 2 °.

[ modulus of elasticity, elongation at break, breaking Strength ]

A polyimide film having a film thickness of about 10 μm was punched into a dumbbell shape according to IEC450 standard, and test pieces were produced, and the initial elastic modulus, elongation at break and breaking strength were measured under conditions of a length between chucks of 30mm and a tensile speed of 2 mm/min using TENSILON manufactured by ORIENTEC Co.

[ coefficient of Linear thermal expansion (CTE) ]

A polyimide film having a film thickness of about 10 μm was cut into a long shape having a width of 4mm, and a test piece was produced, and the temperature was raised to 500℃under conditions of a chuck spacing of 15mm, a load of 2g and a heating rate of 20℃per minute using TMA/SS6100 (manufactured by SII Nanotechnology Co., ltd.). From the obtained TMA curve, the linear thermal expansion coefficient of 150℃to 250℃was determined.

[5% weight loss temperature ]

A polyimide film having a film thickness of about 10 μm was used as a test piece, and the temperature was raised from 25℃to 600℃in a nitrogen gas stream at a temperature-raising rate of 10℃per minute using a calorimeter measurement apparatus (Q5000 IR) manufactured by TA INSTRUMENTS Co. From the resulting weight curve, a 5% weight loss temperature was determined.

< raw materials >

The abbreviations, purities, and the like of the raw materials used in the examples below are as follows.

[ diamine component ]

DABAN:4,4' -diaminobenzanilide

PPD: para-phenylenediamine

BAPB:4,4' -bis (4-aminophenoxy) biphenyl

TPE-Q:1, 4-bis (4-aminophenoxy) benzene

TFMB:2,2' -bis (trifluoromethyl) benzidine

[ tetracarboxylic acid component ]

CpODA: norbornane-2-spiro-alpha-cyclopentanone-alpha' -spiro-2 "-norbornane-5, 5",6 "-tetracarboxylic dianhydride

DNDAxx: (4 arH,8 ach) -decahydro-1 t,4t:5c,8 c-dimethylnaphthalene-2 t,3t,6c,7 c-tetracarboxylic dianhydride

PMDA-H: cyclohexane tetracarboxylic dianhydride

CBDA: cyclobutane tetracarboxylic dianhydride

[ imidazole Compound ]

2-Pz: 2-phenylimidazoles

Bz: benzimidazole derivatives

2-Mz: 2-methylimidazole

[ solvent ]

NMP: n-methyl-2-pyrrolidone

DMAc: dimethylacetamide

The tetracarboxylic acid component and the diamine component used in examples and comparative examples are shown in tables 1 to 1, and the structural formulas of the imidazole compounds used in examples and comparative examples are shown in tables 1 to 2.

[ Table 1-1]

[ tables 1-2]

Example 1]

[ preparation of polyimide precursor composition ]

DABA 2.27g (0.010 mol) was charged into the nitrogen-substituted reaction vessel, and 32.11g of N-methyl-2-pyrrolidone was added in an amount to give a total mass of the monomers (sum of the diamine component and the carboxylic acid component) of 16 mass%, and the mixture was stirred at 50℃for 1 hour. To this solution was slowly added CpODA 3.84g (0.010 mole). Stirring was carried out at 70℃for 4 hours to give a polyimide precursor solution which was uniform and viscous.

2-phenylimidazole as an imidazole compound was dissolved in 4 times by mass of N-methyl-2-pyrrolidone to obtain a uniform solution having a solid content concentration of 2-phenylimidazole of 20% by mass. The solution of the imidazole compound was mixed with the above-synthesized polyimide precursor solution in such a manner that the amount of the imidazole compound was 0.025 mol with respect to 1 mol of the repeating unit of the polyimide precursor, and stirred at room temperature for 3 hours, to obtain a uniform and viscous polyimide precursor composition. The imidization ratio of the polyimide precursor in the obtained polyimide precursor composition was measured and found to be 18%.

[ production of polyimide film ]

As the glass substrate, eagle-XG (registered trademark) (500 μm thick) manufactured by Corning Co., ltd., 6 inches was used. The polyimide precursor composition was applied to a glass substrate by a spin coater, and was directly heated to 415 ℃ from room temperature on the glass substrate under a nitrogen atmosphere (oxygen concentration: 200ppm or less) to thermally imidize the polyimide precursor composition, thereby obtaining a polyimide film/substrate laminate. The laminate was immersed in water at 40 ℃ (for example, in the range of 20 ℃ to 100 ℃), the polyimide film was peeled off from the glass substrate, and after drying, the polyimide film was evaluated for characteristics. The film thickness of the polyimide film was about 10. Mu.m. The evaluation results are shown in Table 2.

< examples 2 to 10>

Polyimide precursor compositions containing polyimide precursors having imidization ratios shown in table 2 were obtained in the same manner as in example 1, except that the imidazole compounds in example 1 were changed to the compounds shown in table 2 (blank columns indicate no addition). Thereafter, a polyimide film was produced in the same manner as in example 1, and the film physical properties were evaluated. The results are shown in Table 2. In examples 1 to 10, the polyimide precursor compositions of examples 1 to 5 and 8 to 10 were also excellent in long-term stability. All of the physical properties of examples 1 to 5 were excellent.

< examples 11 to 17, comparative examples 1 to 3>

In example 1, the imidazole compound was changed to the compound shown in table 3. In addition, the temperature and time after the addition of CpODA were changed in example 1, thereby obtaining polyimide precursor compositions containing polyimide precursors having imidization rates shown in table 3. Thereafter, a polyimide film was produced in the same manner as in example 1, and the film physical properties were evaluated. The results are shown in Table 3.

< examples 18 to 22 and comparative example 4>

In example 1, the diamine component and the imidazole compound were changed to the compounds shown in table 4. In addition, the temperature and time after the addition of CpODA were changed in example 1, thereby obtaining polyimide precursor compositions containing polyimide precursors having imidization rates shown in table 4. Thereafter, a polyimide film was produced in the same manner as in example 1, and the film physical properties were evaluated. The results are shown in Table 4.

< examples 23 to 29, comparative examples 5 and 6>

In example 1, the tetracarboxylic acid component, the diamine component, and the imidazole compound were changed to the compounds shown in table 5. In addition, the temperature and time after the addition of CpODA were changed in example 1, thereby obtaining polyimide precursor compositions containing polyimide precursors having imidization rates shown in table 5. Thereafter, a polyimide film was produced in the same manner as in example 1, and the film physical properties were evaluated. The results are shown in Table 5.

Comparative examples 7 to 10 ]

In example 1, the tetracarboxylic acid component, the diamine component, and the imidazole compound were changed to the compounds shown in table 6. In addition, the temperature and time after the addition of CpODA were changed in example 1, thereby obtaining polyimide precursor compositions containing polyimide precursors having imidization rates shown in table 6. Thereafter, a polyimide film was produced in the same manner as in example 1, and the film physical properties were evaluated. The results are shown in Table 6.

Comparative example 11 ]

To a nitrogen-substituted reaction vessel were added 0.713g (3.136 mmol) of DABA and 1.004g (3.136 mmol) of TFMB, 16.5g of DMAc in an amount to which the total mass of the monomers (the sum of the diamine component and the carboxylic acid component) was added to reach 20 mass%, and the mixture was stirred at room temperature for 1 hour. To this solution was slowly added CpODA 2.411g (6.272 mmol) and stirred at room temperature for 24 hours. Then, the temperature was raised to 160℃and 25mL of toluene was added thereto, and after refluxing toluene for 10 minutes, toluene was extracted and cooled to room temperature, to obtain a uniform and viscous polyimide precursor solution (imidization ratio: 44%). Thereafter, a polyimide film was produced in the same manner as in example 1, and the film physical properties were evaluated. The results are shown in Table 6.

TABLE 2

TABLE 3

TABLE 4

TABLE 5

TABLE 6

From the above results, it was found that the polyimide film obtained from the polyimide precursor composition having the ratio of CpODA in the tetracarboxylic acid component of 70 mol% or more, the ratio of DABAN in the diamine component of 70 mol% or more, and the imidization ratio of less than 50% was large in 400nm transmittance, small in linear thermal expansion coefficient, and high in 5% weight loss temperature.

Industrial applicability

The present invention can be suitably used for manufacturing flexible electronic devices, such as liquid crystal displays, organic EL displays, display devices such as electronic papers, solar cells, and light receiving devices such as CMOS.

Claims

1. A polyimide precursor composition comprising:

the solvent is used for the preparation of the aqueous solution,

[ chemical 1]

In the general formula I, X ₁ Is a 4-valent aliphatic group or an aromatic group, Y ₁ Is a 2-valent aliphatic group or an aromatic group, R ₁ And R is ₂ Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkylsilyl group having 3 to 9 carbon atoms, wherein X ₁ More than 70 mol% of the catalyst is a structure shown in a formula (1-1),

[ chemical 2]

Y ₁ 70 mol% or more of the (D-1) and/or (D-2) is a structure represented by the formula

[ chemical 3]

2. The polyimide precursor composition according to claim 1, wherein the polyimide film obtained from the polyimide precursor composition has a light transmittance of 79% or more, which is a light transmittance at a wavelength of 400nm in the case of a film having a thickness of 10. Mu.m.

3. The polyimide precursor composition according to claim 1 or 2, wherein a polyimide film obtained from the polyimide precursor composition has a linear thermal expansion coefficient of 20ppm/K or less between 150 ℃ and 250 ℃ in the case of a film having a thickness of 10 μm.

4. The polyimide precursor composition according to any one of claims 1 to 3, wherein the polyimide obtained from the polyimide precursor composition has a 5% weight loss temperature of 500 ℃ or higher.

5. The polyimide precursor composition according to any one of claims 1 to 4, wherein the polyimide film obtained from the polyimide precursor composition has an elongation at break of 10% or more in the case of a film having a thickness of 10. Mu.m.

6. The polyimide precursor composition according to any one of claims 1 to 5, wherein X ₁ More than 90 mol% of the above is the structure represented by the above formula (1-1).

7. A polyimide film obtained from the polyimide precursor composition according to any one of claims 1 to 6.

8. A polyimide film/substrate laminate characterized by comprising:

a polyimide film obtained from the polyimide precursor composition according to any one of claims 1 to 6; and

a substrate.

9. The laminate of claim 8, wherein the substrate is a glass substrate.

10. A method for producing a polyimide film/substrate laminate, comprising:

(a) A step of applying the polyimide precursor composition according to any one of claims 1 to 6 to a substrate; and

(b) And a step of heating the polyimide precursor on the substrate and laminating a polyimide film on the substrate.

11. The manufacturing method according to claim 10, wherein the base material is a glass substrate.

12. A method of manufacturing a flexible electronic device, comprising:

(a) A step of applying the polyimide precursor composition according to any one of claims 1 to 6 to a substrate;

(b) A step of producing a polyimide film/substrate laminate in which a polyimide film is laminated on the substrate by heating the polyimide precursor on the substrate;

(d) And a step of peeling the base material from the polyimide film.

13. The method of manufacturing according to claim 12, wherein the base material is a glass substrate.