JPWO2020138360A1 - Imid-amidic acid copolymer and its production method, varnish, and polyimide film - Google Patents

Abstract

An imide-amide acid copolymer containing a repeating unit composed of an imide moiety (I) and an amic acid moiety (A) represented by the following formula (1). (In the formula (1), X1 is a group consisting of a tetravalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and has -O- and -SO2- as a linking group. , -CO-, -CH2-, -C (CH3) 2-, -C2H4O- and -S- may have at least one selected from the group. X2 has 4 carbon atoms different from X1. A group consisting of a tetravalent aliphatic group of ~ 39, an alicyclic group, an aromatic group or a combination thereof, and as a linking group, -O-, -SO2-, -CO-, -CH2-, -C ( CH3) It may have at least one selected from the group consisting of 2-, -C2H4O- and -S-. Y1 is a divalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, and an aromatic group. A group consisting of a group or a combination thereof, which comprises a group consisting of -O-, -SO2-, -CO-, -CH2-, -C (CH3) 2-, -C2H4O- and -S- as a linking group. It may have at least one selected, and the plurality of Y1s have the same composition. S and t are positive integers.)

Description

The present invention relates to an imide-amide acid copolymer which is a precursor of a polyimide resin, a method for producing the same, a varnish containing the copolymer, and a polyimide film.

Various uses of polyimide resins are being studied in the fields of electrical and electronic components and the like. For example, it is desired to replace a glass substrate used in an image display device such as a liquid crystal display or an OLED display with a plastic substrate for the purpose of reducing the weight and flexibility of the device. Research is underway. High transparency is required for the polyimide film for such applications.
Further, when the varnish coated on the glass support or the silicon wafer is heat-cured to form the polyimide film, residual stress is generated in the polyimide film. If the residual stress of the polyimide film is large, there is a problem that the glass support and the silicon wafer are warped. Therefore, the polyimide film is also required to reduce the residual stress.
Further, the required characteristics of the polyimide film are that the phase difference due to birefringence is small and the retardation is low.

Patent Document 1 discloses a polyimide resin synthesized by using α, ω-aminopropyl polydimethylsiloxane and 4,4′-diaminodiphenyl ether as diamine components as a polyimide resin that gives a film having a low residual stress. ..
Patent Document 2 discloses a polyimide film formed by imidizing a polyimide resin precursor synthesized by using bistrifluoromethylbenzidine as a diamine component and silicon-containing diamines as a polyimide film having a low residual stress. There is.

On the other hand, in Patent Document 3, a specific diamine or diisocyanate is copolymerized with biphenyltetracarboxylic acid dianhydride or diphenylsulfonetetracarboxylic acid dianhydride in order to improve solvent solubility, storage stability and heat resistance. The polyimide polymer oligomer is disclosed.

Japanese Unexamined Patent Publication No. 2005-223383 International Publication No. 2014/098235 International Publication No. 2014/199723

In Patent Documents 1 and 2, polyamic acid is used as a precursor of polyimide to try to improve its performance, but polyamic acid has a problem of inferior storage stability. On the other hand, the polyimide resin does not decompose like polyamic acid, but its solubility in a solvent is low, so that the varnish containing polyimide absorbs moisture in the atmosphere, and the film may be whitened during film formation. , It was a problem in molding process. When the polyimide oligomer of Patent Document 3 is used, there is a problem that the yellowness (yellow index, YI) and retardation are high, and the molding processability cannot be said to be sufficient.
As described above, it has been difficult to achieve both storage stability and molding processability.
The present invention has been made in view of such a situation, and the subject of the present invention is an imide-amidoic acid copolymer which is a precursor of a polyimide resin capable of achieving both storage stability and moldability, and an imide-amidoic acid copolymer thereof. It is an object of the present invention to provide a production method, a varnish containing the copolymer, and a polyimide film.

The present inventors have found that a copolymer containing a combination of specific structural units can solve the above-mentioned problems, and have completed the invention.

That is, the present invention relates to the following [1] to [23].
[1]
An imide-amide acid copolymer containing a repeating unit composed of an imide moiety (I) and an amic acid moiety (A) represented by the following formula (1).

（式（１）中、
Ｘ¹は炭素数４〜３９の４価の脂肪族基、脂環基、芳香族基又はこれらの組み合わせからなる基であって、結合基として−Ｏ−、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂−、−Ｃ（ＣＨ₃）₂−、−Ｃ₂Ｈ₄Ｏ−及び−Ｓ−からなる群から選ばれる少なくとも１つを有していてもよい。
Ｘ²はＸ¹とは異なる炭素数４〜３９の４価の脂肪族基、脂環基、芳香族基又はこれらの組み合わせからなる基であって、結合基として−Ｏ−、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂−、−Ｃ（ＣＨ₃）₂−、−Ｃ₂Ｈ₄Ｏ−及び−Ｓ−からなる群から選ばれる少なくとも１つを有していてもよい。
Ｙ¹は炭素数４〜３９の２価の脂肪族基、脂環基、芳香族基又はこれらの組み合わせからなる基であって、結合基として−Ｏ−、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂−、−Ｃ（ＣＨ₃）₂−、−Ｃ₂Ｈ₄Ｏ−及び−Ｓ−からなる群から選ばれる少なくとも１つを有していてもよく、複数のＹ¹は同一の組成を有する。
ｓ及びｔは正の整数である。）

(In equation (1),
X ¹ is a group consisting of a tetravalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and has -O-, -SO _2- , -CO- as a linking group. _{-CH 2 -, - C (CH} 3) 2 -, - it may have at least one member selected from C ₂ H ₄ group consisting of O- and -S-.
X ² is a tetravalent aliphatic group, an alicyclic group, an aromatic group, or combinations of these groups having a carbon number of 4-39, which is different from the X ^1, -O a bonding group -, - SO ₂ - , -CO-, -CH _2- , -C (CH ₃ ) _2- , -C ₂ H ₄ O- and -S- may have at least one selected from the group.
Y ¹ is a group consisting of a divalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and as a linking group, -O-, -SO _2- , -CO-, _{-CH 2 -, - C (CH} 3) 2 -, - it may have at least one member selected from C ₂ H ₄ group consisting of O- and -S-, a plurality of Y ¹ are the same composition Have.
s and t are positive integers. )

[2]
The imide-amide acid copolymer according to the above [1], wherein the s is 1 to 20.
[3]
The imide-amide acid copolymer according to the above [1] or [2], wherein t is 5 to 200.
[4]
The imide-amide according to any one of the above [1] to [3], wherein Y ¹ is a group consisting of a divalent aromatic group having 4 to 39 carbon atoms, diaminoalkylcyclohexane or a combination thereof. Acid copolymer.
[5]
The imide-amide according to any one of the above [1] to [4], wherein X ¹ is a group consisting of a tetravalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, or a combination thereof. Acid copolymer.
[6]
The imide-amide acid copolymer according to any one of the above [1] to [5], wherein X ^{2 is a tetravalent aromatic group having 4 to 39 carbon atoms.}
[7]
The imide moiety (I) has a structural unit IA derived from a tetracarboxylic dianhydride and a structural unit IB derived from a diamine.
The amic acid moiety (A) has a structural unit AA derived from tetracarboxylic dianhydride and a structural unit AB derived from diamine.
Constituent unit IA comprises a structural unit (A-1) derived from alicyclic tetracarboxylic dianhydride (a-1).
The imide-amide acid copolymer according to any one of the above [1] to [6], wherein the structural unit IB and the structural unit AB contain a structural unit derived from an aromatic diamine having an ether bond.
[8]
The imide moiety (I) has a structural unit IA derived from a tetracarboxylic dianhydride and a structural unit IB derived from a diamine.
The amic acid moiety (A) has a structural unit AA derived from tetracarboxylic dianhydride and a structural unit AB derived from diamine.
Constituent unit IA comprises a structural unit (A-1) derived from alicyclic tetracarboxylic dianhydride (a-1).
The imide-amide acid copolymer according to any one of the above [1] to [6], wherein the structural unit IB and the structural unit AB contain a structural unit derived from a fluorine-containing aromatic diamine.
[9]
The imide-amide acid according to the above [7] or [8], wherein the structural unit IB and the structural unit AB include a structural unit (B-1) derived from a compound represented by the following formula (b-1). Polymer.

[10]
Constituent unit AA comprises a structural unit (A-2) derived from tetracarboxylic dianhydride (a-2).
The structural unit (A-2) is derived from the compound represented by the following formula (a-2-1), the structural unit (A-2-1), and the compound represented by the following formula (a-2-2). Constituent unit derived from (A-2-2), structural unit derived from a compound represented by the following formula (a-2-3) (A-2-3), and the following formula (a-2-4). The imide-amide acid according to any one of the above [7] to [9], which comprises at least one selected from the group consisting of structural units (A-2-4) derived from the compound represented by. Polymer.

[11]
The imide-amide acid copolymer according to any one of the above [7] to [10], further containing a structural unit (B-2) derived from a compound represented by the following formula (b-2).

（式（ｂ−２）中、Ｚ^１及びＺ^２はそれぞれ独立に２価の脂肪族基、又は２価の芳香族基を示し、Ｒ^１及びＲ^２はそれぞれ独立に１価の芳香族基又は１価の脂肪族基を示し、Ｒ^３及びＲ^４はそれぞれ独立に１価の脂肪族基を示し、Ｒ^５及びＲ^６は、それぞれ独立に１価の脂肪族基又は１価の芳香族基を示し、ｍ及びｎはそれぞれ独立に１以上の整数を示し、ｍとｎとの和は２〜１０００の整数を示す。但し、Ｒ^１及びＲ^２の少なくとも一方は１価の芳香族基を示す。）

(In formula (b-2), Z ¹ and Z ² each independently represent a divalent aliphatic group or a divalent aromatic group, and R ¹ and R ² each independently represent a monovalent aromatic group. Or monovalent aliphatic groups, R ³ and R ⁴ independently represent monovalent aliphatic groups, and R ⁵ and R ⁶ independently represent monovalent aliphatic groups or monovalent aromatic groups, respectively. Indicates a group, m and n each independently represent an integer of 1 or more, and the sum of m and n represents an integer of 2 to 1000, provided that ^{at least one of R 1} and R ² is a monovalent aromatic group. Shows.)

[12]
The imide-amide acid copolymer according to the above [11], wherein R ¹ and R ² are phenyl groups, and R ³ and R ^{4 are methyl groups.}
[13]
The imide-amide acid copolymer according to the above [11] or [12], wherein the content of the polyorganosiloxane unit in the imide-amide acid copolymer is 5 to 45% by mass.
[14]
The structural unit (A-1) is a structural unit (A-1-1) derived from a compound represented by the following formula (a-1-1), and a compound represented by the following formula (a-1-2). At least one selected from the group consisting of the structural unit (A-1-2) derived from and the structural unit (A-1--3) derived from the compound represented by the following formula (a-1-3). The imide-amide acid copolymer according to any one of the above [7] to [13], which comprises.

[15]
Described in any one of the above [7] to [14], wherein the structural unit IB and the structural unit AB further include a structural unit (B-3) derived from a compound represented by the following formula (b-3). Imid-amide acid copolymer.

（式（ｂ−３）中、Ｒはそれぞれ独立して、水素原子、フッ素原子又は炭素数１〜５のアルキル基を表わす。）

(In formula (b-3), R independently represents a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms.)

[16]
A varnish in which the copolymer according to any one of [1] to [15] is dissolved in an organic solvent.
[17]
A polyimide film containing a polyimide resin obtained by imidizing an amic acid moiety in the copolymer according to any one of [1] to [15].
[18]
The polyimide film according to the above [17], wherein the polyimide resin has a weight average molecular weight (Mw) of 100,000 to 300,000.
[19]
A method for producing an imide-amidoic acid copolymer, which comprises the following steps 1 and 2.
Step 1: The tetracarboxylic acid component constituting the imide moiety (I) is reacted with the diamine component to obtain an imide oligomer. Step 2: The imide oligomer obtained in Step 1 and the amic acid moiety (A) are formed. A step of reacting the tetracarboxylic acid component to obtain an imide-amide acid copolymer containing a repeating unit consisting of an imide moiety (I) and an amic acid moiety (A) represented by the following formula (1).

（式（１）中、
Ｘ¹は炭素数４〜３９の４価の脂肪族基、脂環基、芳香族基又はこれらの組み合わせからなる基であって、結合基として−Ｏ−、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂−、−Ｃ（ＣＨ₃）₂−、−Ｃ₂Ｈ₄Ｏ−及び−Ｓ−からなる群から選ばれる少なくとも１つを有していてもよい。
Ｘ²はＸ¹とは異なる炭素数４〜３９の４価の脂肪族基、脂環基、芳香族基又はこれらの組み合わせからなる基であって、結合基として−Ｏ−、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂−、−Ｃ（ＣＨ₃）₂−、−Ｃ₂Ｈ₄Ｏ−及び−Ｓ−からなる群から選ばれる少なくとも１つを有していてもよい。
Ｙ¹は炭素数４〜３９の２価の脂肪族基、脂環基、芳香族基又はこれらの組み合わせからなる基であって、結合基として−Ｏ−、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂−、−Ｃ（ＣＨ₃）₂−、−Ｃ₂Ｈ₄Ｏ−及び−Ｓ−からなる群から選ばれる少なくとも１つを有していてもよく、複数のＹ¹は同一の組成を有する。
ｓ及びｔは正の整数である。）

(In equation (1),
X ¹ is a group consisting of a tetravalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and has -O-, -SO _2- , -CO- as a linking group. _{-CH 2 -, - C (CH} 3) 2 -, - it may have at least one member selected from C ₂ H ₄ group consisting of O- and -S-.
X ² is a tetravalent aliphatic group, an alicyclic group, an aromatic group, or combinations of these groups having a carbon number of 4-39, which is different from the X ^1, -O a bonding group -, - SO ₂ - , -CO-, -CH _2- , -C (CH ₃ ) _2- , -C ₂ H ₄ O- and -S- may have at least one selected from the group.
Y ¹ is a group consisting of a divalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and as a linking group, -O-, -SO _2- , -CO-, _{-CH 2 -, - C (CH} 3) 2 -, - it may have at least one member selected from C ₂ H ₄ group consisting of O- and -S-, a plurality of Y ¹ are the same composition Have.
s and t are positive integers. )

[20]
The method for producing an imide-amide acid copolymer according to the above [19], wherein the imide oligomer obtained in step 1 has amino groups at both ends of the main chain of the molecular chain.
[21]
The imide-amide acid copolymer according to the above [19] or [20], wherein in step 1, the molar ratio of the diamine component to the tetracarboxylic acid component (diamine / tetracarboxylic acid) is 1.01 to 2. Production method.
[22]
The tetracarboxylic acid component constituting the imide moiety (I) used in step 1 is an alicyclic tetracarboxylic acid component, and the tetracarboxylic acid component constituting the amic acid moiety (A) used in step 2 is aromatic. The method for producing an imide-amidoic acid copolymer according to any one of the above [19] to [21], which is a group tetracarboxylic acid component.
[23]
The method for producing an imide-amide acid copolymer according to any one of [19] to [22] above, wherein a diamine containing a polyorganosiloxane unit is reacted after the completion of step 2.

According to the present invention, an imide-amidoic acid copolymer which is a precursor of a polyimide resin capable of achieving both storage stability and moldability, a method for producing the same, a varnish containing the copolymer, and a polyimide film are provided. Can be provided.

[Imid-amide acid copolymer]
The imide-amide acid copolymer of the present invention contains a repeating unit composed of an imide moiety (I) and an amic acid moiety (A) represented by the following formula (1).

（式（１）中、
Ｘ¹は炭素数４〜３９の４価の脂肪族基、脂環基、芳香族基又はこれらの組み合わせからなる基であって、結合基として−Ｏ−、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂−、−Ｃ（ＣＨ₃）₂−、−Ｃ₂Ｈ₄Ｏ−及び−Ｓ−からなる群から選ばれる少なくとも１つを有していてもよい。
Ｘ²はＸ¹とは異なる炭素数４〜３９の４価の脂肪族基、脂環基、芳香族基又はこれらの組み合わせからなる基であって、結合基として−Ｏ−、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂−、−Ｃ（ＣＨ₃）₂−、−Ｃ₂Ｈ₄Ｏ−及び−Ｓ−からなる群から選ばれる少なくとも１つを有していてもよい。
Ｙ¹は炭素数４〜３９の２価の脂肪族基、脂環基、芳香族基又はこれらの組み合わせからなる基であって、結合基として−Ｏ−、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂−、−Ｃ（ＣＨ₃）₂−、−Ｃ₂Ｈ₄Ｏ−及び−Ｓ−からなる群から選ばれる少なくとも１つを有していてもよく、複数のＹ¹は同一の組成を有する。
ｓ及びｔは正の整数である。）

(In equation (1),
X ¹ is a group consisting of a tetravalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and has -O-, -SO _2- , -CO- as a linking group. _{-CH 2 -, - C (CH} 3) 2 -, - it may have at least one member selected from C ₂ H ₄ group consisting of O- and -S-.
X ² is a tetravalent aliphatic group, an alicyclic group, an aromatic group, or combinations of these groups having a carbon number of 4-39, which is different from the X ^1, -O a bonding group -, - SO ₂ - , -CO-, -CH _2- , -C (CH ₃ ) _2- , -C ₂ H ₄ O- and -S- may have at least one selected from the group.
Y ¹ is a group consisting of a divalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and as a linking group, -O-, -SO _2- , -CO-, _{-CH 2 -, - C (CH} 3) 2 -, - it may have at least one member selected from C ₂ H ₄ group consisting of O- and -S-, a plurality of Y ¹ are the same composition Have.
s and t are positive integers. )

<Imide portion (I)>
The imide moiety (I) constituting the imide-amide acid copolymer of the present invention is the moiety represented by (I) of the above formula (1).
In the above formula (1), X ¹ is a group consisting of a tetravalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and has −O−, − as a linking group. It may have at least one selected from the group consisting of _{SO 2-} , -CO-, -CH _2- , -C (CH ₃ ) _2- , -C ₂ H _{4 O- and -S-.} Among them, a group consisting of a tetravalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group or a combination thereof is preferable, and a group consisting of a tetravalent alicyclic group having 4 to 39 carbon atoms. Is more preferable.
When X ¹ is an aliphatic group or an alicyclic group, the transparency of the polyimide is improved and the retardation is lowered, which is preferable. Further, it is preferable because the elongation of the polyimide film is improved.
X ¹ is obtained by removing two dicarboxylic acid anhydride portions (four carboxy group portions) from the tetracarboxylic acid dianhydride which is a raw material of the constituent unit IA derived from the tetracarboxylic acid dianhydride described later. Is preferable.

In the above formula (1), Y ¹ is a group consisting of a divalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and as a linking group, -O-,-. It may have at least one selected from the group consisting of _{SO 2-} , -CO-, -CH _2- , -C (CH ₃ ) _2- , -C ₂ H _{4 O- and -S-.} Among them, a divalent aromatic group having 4 to 39 carbon atoms, a diaminoalkylcyclohexane or a group composed of a combination thereof is preferable.
Here, a plurality of Y ¹ have the same composition. The "same composition", 1 if the type having a structure of Y ¹ from diamine refers to Y ¹ represented by the formula (1) having all the same structure, from multiple diamines of Y ¹ if they have structural means that each Y ¹ represented by the formula (1) it is present the structure of Y ¹ from each diamine in the same proportion. ^{That is, when having a structure of Y 1} derived from a plurality of diamines, even if each Y ¹ is different in each molecule, in all the molecules, ^{the positions of all Y 1} are in the same proportion. There is a structure ^{of Y 1} derived from diamine.
It is preferable that Y ¹ is obtained by removing the two amino group portions from the diamine which is the raw material of the structural unit IB derived from the diamine described later.

In the formula (1), s is the number of repeating units in the imide moiety (I) and is a positive integer.
From the viewpoint of storage stability and moldability, s is preferably 1 to 20, more preferably 1 to 15, further preferably 1 to 10, and preferably 1 to 5. Even more preferable. The average number of repetitions of the imide moiety (I), that is, the average value of s is preferably 1 to 10, more preferably 1.5 to 9, and even more preferably 1.5 to 8. It is even more preferably 1.7 to 5. The average number of repetitions of the imide portion (I) refers to the average number of repetitions of the imide portion (I) of all the imide-amide acid copolymers contained in the polyimide varnish and the polyimide film described later, and the average number of repetitions of s. The average value refers to the average value of s of all the imide-amidic acid copolymers contained in the polyimide varnish and the polyimide film described later.

<Amidic acid moiety (A)>
The amic acid moiety (A) constituting the imide-amidoic acid copolymer of the present invention is the moiety represented by (A) of the above formula (1).
In the formula (1), X ² is a group composed of a tetravalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group, or a combination thereof, which is different from ^{X 1, and serves as a bonding group.} _{-O -, - SO 2 -,} - CO -, - CH 2 -, - C (CH 3) 2 -, - C 2 H 4 at least one of a member selected from the group consisting of O- and -S- It may be a tetravalent aromatic group having 4 to 39 carbon atoms.
It is preferable that X ² is an aromatic group because the heat resistance of the polyimide is improved.
It ^{is preferable that X 2} is obtained by removing two carboxylic acid anhydride portions from the tetracarboxylic acid dianhydride which is a raw material of the structural unit AA derived from the tetracarboxylic acid dianhydride which will be described later.

In the formula (1), Y ¹ is the same as that described for the imide moiety (I).
It is preferable that Y ¹ is obtained by removing the two amino group portions from the diamine which is the raw material of the constituent unit AB derived from the diamine described later.

In the formula (1), t is the number of repeating units consisting of the imide moiety (I) and the amic acid moiety (A) contained in the imide-amidoic acid copolymer of the present invention, and is a positive integer. From the viewpoint of storage stability and moldability, t is preferably 5 to 200, more preferably 6 to 150, and even more preferably 10 to 120. The average number of repetitions of the repeating unit composed of the imide moiety (I) and the amic acid moiety (A), that is, the average value of t is preferably 5 to 200, more preferably 6 to 150, and 10 It is more preferably ~ 120. The average number of repetitions of the repeating unit composed of the imide moiety (I) and the amic acid moiety (A) is the same as the imide moiety (I) of all the imide-amide acid copolymers contained in the polyimide varnish and the polyimide film described later. It refers to the number of repetitions of the repeating unit composed of the amic acid moiety (A), and the average value of t is the average value of t of all the imide-amidic acid copolymers contained in the polyimide varnish and the polyimide film described later. Say that.

In the conventional imide-amide acid copolymer, the imide moiety and the amic acid moiety are randomly present, whereas in the imide-amide acid copolymer of the present invention, the imide moiety (I) and the amic acid moiety ( It is considered that when A) has a specific structure, both storage stability and molding processability can be achieved at the same time.

<Imide-amide copolymer embodiment>
The imide-amide acid copolymer of the present invention contains a repeating unit composed of an imide moiety (I) and an amic acid moiety (A) represented by the above formula (1), and the specific embodiment thereof. It is shown below.

As the first specific embodiment of the imide-amide acid copolymer of the present invention, the imide moiety (I) may be a structural unit IA derived from tetracarboxylic acid dianhydride and a structural unit IB derived from diamine. The amic acid moiety (A) has a structural unit AA derived from tetracarboxylic acid dianhydride and a structural unit AB derived from diamine, and the structural unit IA is an alicyclic tetracarboxylic acid dianhydride. The structural unit (A-1) derived from (a-1) is contained, and the structural unit IB and the structural unit AB include a structural unit derived from an aromatic diamine having an ether bond.

Further, as a second specific embodiment of the imide-amide acid copolymer of the present invention, the imide moiety (I) is a structural unit derived from tetracarboxylic acid dianhydride and a structural unit derived from diamine. It has an IB, the amic acid moiety (A) has a structural unit AA derived from tetracarboxylic acid dianhydride and a structural unit AB derived from diamine, and the structural unit IA is an alicyclic tetracarboxylic acid dianhydride. It contains a structural unit (A-1) derived from the anhydride (a-1), and the structural unit IB and the structural unit AB include a structural unit derived from a fluoroaromatic diamine.

(Constituent unit IA)
The structural unit IA is a structural unit derived from the tetracarboxylic dianhydride occupying the imide portion (I) of the copolymer of the present invention, and includes a structural unit derived from the alicyclic tetracarboxylic dianhydride. It is preferable, and it is more preferable to contain a structural unit (A-1) derived from the alicyclic tetracarboxylic dianhydride (a-1).
In the present specification, the alicyclic tetracarboxylic dianhydride means a tetracarboxylic dianhydride in which at least one of the carbon atoms to which four carboxy groups are bonded constitutes an alicyclic structure, and is aromatic. The group tetracarboxylic dianhydride means a tetracarboxylic dianhydride in which at least one of the carbon atoms to which four carboxy groups are bonded constitutes an aromatic ring structure, and the aliphatic tetracarboxylic dianhydride is an aliphatic tetracarboxylic dianhydride. It means tetracarboxylic dianhydride in which all of the carbon atoms to which the four carboxy groups are bonded are aliphatic carbons.

The structural unit (A-1) is a structural unit derived from the alicyclic tetracarboxylic dianhydride (a-1).
The structural unit (A-1) is preferably a structural unit (A-1-1) derived from a compound represented by the following formula (a-1-1), and is represented by the following formula (a-1-2). At least one selected from the group consisting of a structural unit (A-1-2) derived from a compound and a structural unit (A-1--3) derived from a compound represented by the following formula (a-1-3). From the viewpoint of high transparency, high heat resistance and low residual stress, it more preferably contains a structural unit (A-1-1) derived from a compound represented by the following formula (a-1-1). .. The compound represented by the formula (a-1-1) is norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'', 6,6''-. The compound represented by the formula (a-1-3), which is a tetracarboxylic dianhydride (CpODA), is 5,5'-bis-2-norbornne-5,5', 6,6'-tetracarboxylic. Acid-5,5', 6,6'-dianhydride (BNBDA).

The total ratio of the structural units (A-1-1) to (A-1--3) in the structural unit (A-1) is preferably 45 mol% or more, more preferably 70 mol% or more, still more preferably. Is 90 mol% or more, particularly preferably 99 mol% or more. The upper limit of the ratio is not particularly limited, that is, 100 mol%.
The constituent unit (A-1) may include at least one selected from the constituent units (A-1-1) to (A-1--3), and the constituent units (A-1-1) to (A-1-1). It may consist of only one of A-1-3).
In particular, the ratio of the structural unit (A-1-1) in the structural unit (A-1) is preferably 45 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, and particularly preferably 90 mol% or more. It is 99 mol% or more. The upper limit of the ratio is not particularly limited, that is, 100 mol%.

The structural unit (A-1) has a structural unit derived from an alicyclic tetracarboxylic dianhydride other than the compounds represented by the formulas (a-1-1) to (a-1-3). You may. Examples of such alicyclic tetracarboxylic acid dianhydride include 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, 1,2, 4,5-Cyclohexanetetracarboxylic acid dianhydride, bicyclo [2.2.2] octa-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, dicyclohexyltetracarboxylic acid dianhydride, etc. Can be mentioned. Among these, structural units derived from alicyclic tetracarboxylic dianhydrides other than the compounds represented by the formulas (a-1-1) to (a-1--3) in the structural unit (A-1). As, a structural unit derived from 1,2,4,5-cyclohexanetetracarboxylic dianhydride is preferable.
The alicyclic tetracarboxylic dianhydride (a-1) may be used alone or in combination of two or more.

(Constituent unit AA)
The structural unit AA is a structural unit derived from the tetracarboxylic acid dianhydride occupying the amic acid portion (A) of the copolymer of the present invention, and is other than the alicyclic tetracarboxylic acid dianhydride (a-1). It is more preferable to contain a structural unit (A-2) derived from the tetracarboxylic acid dianhydride (a-2).

The structural unit (A-2) is a structural unit derived from a tetracarboxylic dianhydride (a-2) other than the alicyclic tetracarboxylic dianhydride (a-1). Examples of the tetracarboxylic acid dianhydride (a-2) include one or more selected from the group consisting of aromatic tetracarboxylic acid dianhydride and aliphatic tetracarboxylic acid dianhydride, and aromatic tetracarboxylic acid. It preferably contains a dianhydride. That is, the structural unit (A-2) preferably contains a structural unit derived from aromatic tetracarboxylic dianhydride.
That is, the structural unit AA preferably contains a structural unit derived from an aromatic tetracarboxylic dianhydride.
The structural unit (A-2) is a structural unit (A-2-1) derived from a compound represented by the following formula (a-2-1) from the viewpoint of high heat resistance and low residual stress, and the following formula. A structural unit (A-2-2) derived from a compound represented by (a-2-2) and a structural unit (A-2-3) derived from a compound represented by the following formula (a-2-3). ), And at least one selected from the group consisting of the structural unit (A-2-4) derived from the compound represented by the following formula (a-2-4).

The compound represented by the formula (a-2-1) is biphenyltetracarboxylic dianhydride (BPDA), and specific examples thereof are 3,3 represented by the following formula (a-2-1s). ', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3', 4'-biphenyltetracarboxylic dianhydride represented by the following formula (a-2-1a) Examples thereof include (a-BPDA) and 2,2', 3,3'-biphenyltetracarboxylic dianhydride (i-BPDA) represented by the following formula (a-2-1i). Of these, 3,3', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) represented by the following formula (a-2-1s) is preferable.

The compound represented by the formula (a-2-2) is p-phenylenebis (trimeritate) dianhydride (TAHQ).

The compound represented by the formula (a-2-3) is oxydiphthalic anhydride (ODPA), and specific examples thereof are 4,4'-oxydiphthal represented by the following formula (a-2-3s). Acid anhydride (s-ODPA), 3,4'-oxydiphthalic anhydride (a-ODPA) represented by the following formula (a-2-3a), represented by the following formula (a-2-3i) Examples include 3,3'-oxydiphthalic anhydride (i-ODPA). Of these, 4,4'-oxydiphthalic anhydride (s-ODPA) represented by the following formula (a-2-3s) is preferable.

The compound represented by the formula (a-2-4) is pyromellitic acid dianhydride (PMDA).

The structural unit (A-2) is at least one selected from the group consisting of the structural unit (A-2-1) and the structural unit (A-2-2) from the viewpoint of high heat resistance and low residual stress. Is preferably included.
The structural unit (A-2-1) is preferable from the viewpoint of improving the heat resistance and thermal stability of the film and further reducing the residual stress, and the structural unit (A-2-2) has a reduced YI and is colorless and transparent. It is preferable from the viewpoint of being superior.

The tetracarboxylic dianhydride (a-2) may contain a tetracarboxylic dianhydride other than the compounds represented by the formulas (a-2-1) to (a-2-4). Examples of such tetracarboxylic acid dianhydride include 4,4'-(hexafluoroisopropylidene) diphthalic acid anhydride, 3,3', 4,4'-diphenylsulfone tetracarboxylic acid dianhydride, 3,3',. Fragrances such as 4,4'-benzophenone tetracarboxylic acid dianhydride, 2,2', 3,3'-benzophenone tetracarboxylic acid dianhydride, and compounds represented by the following formula (a-2-5). Tetracarboxylic acid dianhydride; and aliphatic tetracarboxylic acid dianhydrides such as 1,2,3,4-butanetetracarboxylic acid dianhydride. Of these, aromatic tetracarboxylic dianhydrides are preferred.
The tetracarboxylic dianhydride (a-2) may be used alone or in combination of two or more.

The total ratio of the structural units (A-2-1) to (A-2-4) in the structural unit (A-2) is preferably 45 mol% or more, more preferably 70 mol% or more, still more preferably. Is 90 mol% or more, particularly preferably 99 mol% or more. The upper limit of the ratio is not particularly limited, that is, 100 mol%. The structural unit (A-2) may include at least one selected from the structural units (A-2-1) to (A-2-4), and the structural units (A-2-1) to (A-2-1). It may consist of only one of A-2-4).
When the structural unit (A-2) contains two or more types of structural units selected from the structural units (A-2-1) to (A-2-4), each configuration in the structural unit (A-2) There is no particular limitation on the unit ratio, and any ratio can be used.

The ratio of the structural unit derived from the aromatic tetracarboxylic dianhydride in the structural unit (A-2) is preferably 45 mol% or more, more preferably 60 mol% or more, still more preferably 85 mol% or more. be. The upper limit of the total content ratio is not particularly limited, that is, 100 mol%.

The molar ratio of the structural unit (A-1) to the structural unit (A-2) in the structural unit derived from the tetracarboxylic dianhydride of the imide-amide acid copolymer [(A-1) / (A). -2) Molar ratio] is preferably 10/90 to 90/10, more preferably 30/70 to 85/15, and even more preferably 50/50 to 80/20.

(Constituent unit IB and constituent unit AB)
The structural unit IB and the structural unit AB are structural units derived from diamines in the imide moiety (I) and the amic acid moiety (A) of the copolymer of the present invention, respectively. (Hereinafter, the constituent unit IB and the constituent unit AB are also collectively referred to as "constituent unit B").
The structural unit IB and the structural unit AB preferably include a structural unit derived from an aromatic diamine having an ether bond or a structural unit derived from a fluorine-containing aromatic diamine, and from the viewpoint of flexibility, an aromatic having an ether bond. It is more preferable to include a structural unit derived from a group diamine, and from the viewpoint of transparency, it is more preferable to include a structural unit derived from a fluorine-containing aromatic diamine.

The constituent unit IB and the constituent unit AB have the same composition. The "same composition" means that when it is composed of one kind of diamine-derived structural unit, the structural unit IB and the structural unit AB are all composed of the same structural unit, and when it is composed of a plurality of diamine-derived structural units. It means that the constituent units IB and the constituent unit AB have the same proportion of each diamine-derived constituent unit. That is, when it is composed of a plurality of diamine-derived constituent units, even if the constituent units of the constituent unit IB and the constituent unit AB are different in each molecule, all the molecules are derived from each diamine in the same proportion. There is a structural unit of.

Examples of the aromatic diamine having an ether bond that gives a structural unit derived from the aromatic diamine having an ether bond include 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether (6FODA), 2 , 2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane (HFBAPP), bis [4- (4-aminophenoxy) phenyl] sulfone (BAPS), 2,2-bis [4- (4- (4- (4- (4-)4-) Aminophenoxy) phenyl] propane (BAPP), 4,4'-bis (4-aminophenoxy) biphenyl (BODA), 4,4'-diaminodiphenyl ether (ODA), 3,4'-diaminodiphenyl ether and the like. 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether (6FODA) is preferable.

Examples of the fluorine-containing aromatic diamine that gives a structural unit derived from the fluorine-containing aromatic diamine include 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether (6FODA) and 2,2-bis [ 4- (4-Aminophenoxy) phenyl] hexafluoropropane (HFBAPP) and the like can be mentioned, and 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether (6FODA) is preferable.

As described above, the structural unit B preferably contains the structural unit (B-1) derived from the compound represented by the following formula (b-1). When the structural unit B includes the structural unit (B-1), it is possible to achieve both excellent transparency and low residual stress and low retardation characteristics.

The compound represented by the formula (b-1) is 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether (6FODA).

The structural unit B preferably further contains a structural unit (B-3) derived from the compound represented by the following formula (b-3).

In the above formula (b-3), R is independently selected from the group consisting of a hydrogen atom, a fluorine atom, and an alkyl group having 1 to 5 carbon atoms, and is selected from the hydrogen atom, the fluorine atom, and the methyl group. It is preferably selected from the above group, and a hydrogen atom is more preferable.
Examples of the compound represented by the above formula (b-3) include 9,9-bis (4-aminophenyl) fluorene (BAFL), 9,9-bis (3-fluoro-4-aminophenyl) fluorene, and 9. , 9-Bis (3-methyl-4-aminophenyl) fluorene and the like, and at least one selected from the group consisting of these three compounds is preferable, and 9,9-bis (4-aminophenyl) fluorene is preferable. More preferred.
The copolymer of the present invention has improved transparency and heat resistance by containing the structural unit (B-3).

The ratio of the structural unit (B-1) in the structural unit B is preferably 45 mol% or more, more preferably 48 mol% or more, still more preferably 85 mol% or more, still more preferably 88 mol% or more. It is preferably 100 mol% or less, more preferably 99.5 mol% or less, still more preferably 99.0 mol% or less. The structural unit B may consist of only the structural unit (B-1).
When the constituent unit B includes the constituent unit (B-3), the ratio of the constituent unit (B-3) in the constituent unit B is preferably 5 mol% or more, more preferably 10 mol, from the viewpoint of low residual stress. % Or more, more preferably 25 mol% or more, and preferably 65 mol% or less, more preferably 55 mol% or less, still more preferably 50 mol% or less.
When the constituent unit B includes the constituent unit (B-3), the total ratio of the constituent units (B-1) and (B-3) in the constituent unit B is preferably 85.0 to 100 mol%. It is more preferably 88.0 to 99.5 mol%, still more preferably 92.0 to 99.0 mol%. When the constituent unit B does not include the constituent unit (B-3), the ratio of the constituent units (B-1) in the constituent unit B is also preferably in the same range as described above.

The structural unit B may contain a structural unit derived from an aromatic diamine having a sulfonyl group from the viewpoint of flexibility.
Examples of the aromatic diamine having a sulfonyl group that gives a structural unit derived from the aromatic diamine having a sulfonyl group include 3,3'-diaminodiphenyl sulfone (3,3-DDS) and 4,4'-diaminodiphenyl sulfone ( 4,4-DDS), bis [4- (4-aminophenoxy) phenyl] sulfone (BAPS), bis [4- (3-aminophenoxy) phenyl] sulfone (BAPS-M) and the like.

The structural unit B is derived from the diamine exemplified in the above-mentioned structural unit derived from an aromatic diamine having an ether bond, a structural unit derived from a fluorine-containing aromatic diamine, and a structural unit derived from an aromatic diamine having a sulfonyl group. It may contain a structural unit other than the structural unit to be used, and other structural units derived from diamines other than the structural units (B-1) and (B-3).
The diamine giving such a constituent unit is not particularly limited, but is limited to 1,4-phenylenediamine, p-xylylene diamine, 3,5-diaminobenzoic acid, 1,5-diaminonaphthalene, and 2,2'-dimethyl. Biphenyl-4,4'-diamine, 2,2'-dimethylbiphenyl-4,4'-diamine, 4,4'-diaminodiphenylmethane, 1,4-bis [2- (4-aminophenyl) -2-propyl ] Benzene, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4'-diaminobenzanilide, 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl- 1H-inden-5-amine, α, α'-bis (4-aminophenyl) -1,4-diisopropylbenzene, N, N'-bis (4-aminophenyl) terephthalamide, 2,2-bis (3) Aromatic amines such as −amino-4-hydroxyphenyl) hexafluoropropane and 1,4-bis (4-aminophenoxy) benzene; 1,3-bis (aminomethyl) cyclohexane, and 1,4-bis (amino). Alicyclic diamines such as methyl) cyclohexane; and aliphatic diamines such as ethylenediamine and hexamethylenediamine can be mentioned.
The other diamine-derived structural units arbitrarily contained in the structural unit B may be one type or two or more types.
The structural unit B preferably does not contain a structural unit derived from 2,2'-bis (trifluoromethyl) benzidine, particularly from the viewpoint of achieving low retardation.

In the present specification, the aromatic diamine means a diamine containing one or more aromatic rings, and the alicyclic diamine means a diamine containing one or more alicyclic rings and not containing an aromatic ring, and is a fat. The group diamine means a diamine that does not contain an aromatic ring or an alicyclic ring.

(Other building blocks)
The imide-amidoic acid copolymer of the present invention may also contain structural units other than the above-mentioned structural unit IA, structural unit AA, structural unit IB and structural unit AB.
The imide-amidoic acid copolymer of the present invention preferably further contains a structural unit (B-2) derived from a compound represented by the following general formula (b-2). Residual stress is reduced by including the structural unit (B-2).

In formula (b-2), Z ¹ and Z ² independently represent a divalent aliphatic group or a divalent aromatic group, and R ¹ and R ² independently represent a monovalent aromatic group, respectively. Or monovalent aliphatic groups, R ³ and R ⁴ independently represent monovalent aliphatic groups, and R ⁵ and R ⁶ independently represent monovalent aliphatic groups or monovalent fragrances, respectively. Indicates a group group, m and n each independently indicate an integer of 1 or more, and the sum of m and n indicates an integer of 2 to 1000. However, ^{at least one of R 1} and R ² shows a monovalent aromatic group.
In addition, in the formula (b-2), two or more different repeating units described in parallel by [] may be repeated in any form and order of random, alternating, or block, respectively.

In formula (b-2), the ^{divalent aliphatic group or divalent aromatic group in Z 1} and Z ² may be substituted with a fluorine atom or may contain an oxygen atom. When an oxygen atom is contained as an ether bond, the carbon number shown below means all the carbon numbers contained in the aliphatic group or the aromatic group.
Examples of the divalent aliphatic group include a divalent saturated or unsaturated aliphatic group having 1 to 20 carbon atoms. The divalent aliphatic group preferably has 3 to 20 carbon atoms.
Examples of the divalent saturated aliphatic group include an alkylene group having 1 to 20 carbon atoms and an alkyleneoxy group, and examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group and a hexa. Methylene group, octamethylene group, decamethylene group, dodecamethylene group and the like can be exemplified, and examples of the alkyleneoxy group include propyleneoxy group and trimethyleneoxy group.
Examples of the divalent unsaturated aliphatic group include an alkylene group having 2 to 20 carbon atoms, and examples thereof include a vinylene group, a propenylene group, and an alkylene group having an unsaturated double bond at the terminal.
Examples of the divalent aromatic group include an arylene group having 6 to 20 carbon atoms and an aralkylene group having 7 to 20 carbon atoms. Specific examples of the arylene group having 6 to 20 carbon atoms in Z ¹ and Z ² include an o-phenylene group, an m-phenylene group, a p-phenylene group, a 4,4'-biphenylylene group, a 2,6-naphthylene group and the like. Can be mentioned.
As Z ¹ and Z ² , a trimethylene group and a p-phenylene group are particularly preferable, and a trimethylene group is more preferable.

In the formula (b-2), the ^{monovalent aliphatic group in R 1 to} R ⁶ includes a monovalent saturated or unsaturated aliphatic group. Examples of the monovalent saturated aliphatic group include an alkyl group having 1 to 22 carbon atoms, and examples thereof include a methyl group, an ethyl group, and a propyl group. Examples of the monovalent unsaturated aliphatic group include an alkenyl group having 2 to 22 carbon atoms, and examples thereof include a vinyl group and a propenyl group. These groups may be substituted with fluorine atoms.
^{The monovalent aromatic group in R 1} , R ² , R ⁵ and R ⁶ of the formula (b-2) is an aryl group having 6 to 20 carbon atoms, 7 to 30 carbon atoms, and is substituted with an alkyl group. Examples thereof include the aryl group and the aralkyl group having 7 to 30 carbon atoms. As the monovalent aromatic group, an aryl group is preferable, and a phenyl group is more preferable.
At least one of ^{R 1} and R ² shows a monovalent aromatic group, but it is preferable that both ^{R 1} and R ^{2 are monovalent aromatic groups, and both R 1} and R ² are phenyl groups. Is more preferable.
As R ³ and R ⁴ , an alkyl group having 1 to 6 carbon atoms is preferable, and a methyl group is more preferable.
As R ⁵ and R ⁶ , a monovalent aliphatic group is preferable, and a methyl group is more preferable.

In the formula (b-2), m indicates the number of repetitions of the siloxane unit to which at least one monovalent aromatic group is bonded, and n indicates the number of repetitions of the siloxane unit to which the monovalent aliphatic group is bonded.
m and n each independently represent an integer of 1 or more, and the sum of m and n (m + n) represents an integer of 2 to 1000. The sum of m and n preferably represents an integer of 3 to 500, more preferably 3 to 100, and even more preferably an integer of 3 to 50.
The ratio of m / n is preferably 50/50 to 99/1, more preferably 60/40 to 90/10, and even more preferably 70/30 to 80/20.

The functional group equivalent of the compound represented by the formula (b-2) is preferably 150 to 5,000 g / mol, more preferably 400 to 4,000 g / mol, and further preferably 500 to 3,000 g / mol. ..
The functional group equivalent means the mass of the compound represented by the formula (b-2) per mole of the functional group.
The compound represented by the general formula (b-2) may be the following general formula (b-21).

（式（ｂ−２１）中、Ｚ¹、Ｚ²、Ｒ¹〜Ｒ⁶、ｍ及びｎは式（ｂ−２）で示したものと同じである。）

(In the formula (b-21), Z ¹ , Z ² , R ^{1 to} R ⁶ , m and n are the same as those shown in the formula (b-2).)

The ratio of the constituent unit (B-2) to the total amount of the constituent unit (B-2) and the constituent unit B is preferably 0.01 to 15.0 mol%, more preferably 0.5 to 12.0 mol%. , More preferably 1.0 to 8.0 mol%.

The content of the polyorganosiloxane unit with respect to the total of the structural units constituting the imide-amidoic acid copolymer is preferably 5 to 45% by mass, more preferably 7 to 40% by mass, still more preferably 10 to 35% by mass. be. When the content of the polyorganosiloxane unit is within the above range, low retardation and low residual stress can be achieved at a higher level.

Examples of commercially available compounds represented by the formula (b-2) include "X-22-9409" and "X-22-1660B-3" manufactured by Shin-Etsu Chemical Co., Ltd.

(Preferable example of imide repeating structural unit / amic acid structural unit)
The copolymer of the present invention is an imide repeating structural unit formed from a compound giving a structural unit (A-1) and a compound giving a structural unit (B-1), and a compound giving a structural unit (A-2). It is preferable to have an amic acid structural unit formed from the compound which gives the structural unit (B-1).

That is, the copolymer of the present invention is a copolymer having structural units IA and AA derived from tetracarboxylic dianhydride and structural units IB and AB derived from diamine.
The constituent units IA and AA are a constituent unit (A-1) derived from the alicyclic tetracarboxylic dianhydride (a-1) and a tetra other than the alicyclic tetracarboxylic dianhydride (a-1). Consists of a structural unit (A-2) derived from the carboxylic dianhydride (a-2)
Constituent units IB and AB include a structural unit (B-1) derived from a compound represented by the following formula (b-1).
The structural unit (A-2) is derived from the compound represented by the following formula (a-2-1), the structural unit (A-2-1), and the compound represented by the following formula (a-2-2). The structural unit (A-2-2) derived from, the structural unit (A-2-3) derived from the compound represented by the following formula (a-2-3), and the following formula (a-2-4). Containing at least one selected from the group consisting of structural units (A-2-4) derived from the compound represented by.
The copolymer has an imide repeating structural unit formed from a compound giving a structural unit (A-1) and a compound giving a structural unit (B-1), and gives a structural unit (A-2). It is preferable to have an amic acid structural unit formed from the compound which gives the structural unit (B-1).

The copolymer of the present invention is composed of an imide repeating structural unit formed from a compound other than the compound giving the structural unit (A-1) and a compound giving the structural unit B, and a compound giving the structural unit (A-1). It may have an imide repeating structural unit formed from a compound other than the compound giving the unit (B-1). Similarly, the copolymer of the present invention may have an amic acid structural unit formed from a compound other than the compound giving the structural unit (A-2) and a compound giving the structural unit (B-1). good.

<Physical properties of polyimide film>
By using the imide-amidoic acid copolymer of the present invention, a polyimide film having excellent colorless transparency and heat resistance, low residual stress, and low retardation can also be formed. Suitable physical property values of the film are as follows.
The total light transmittance is preferably 87% or more, more preferably 89% or more, still more preferably 90% or more when the film has a thickness of 10 μm.
The yellow index (YI) is preferably 7.0 or less, more preferably 4.0 or less, still more preferably 3.5 or less, and even more preferably 3.0 or less when the film has a thickness of 10 μm. ..
The glass transition temperature (Tg) is preferably 220 ° C. or higher, more preferably 250 ° C. or higher, still more preferably 290 ° C. or higher.
The absolute value of the thickness phase difference (Rth) when a polyimide film having a thickness of 10 μm is formed is preferably 200 nm or less, more preferably 150 nm or less, still more preferably 110 nm or less, and particularly preferably 90 nm or less. In the present specification, "low retardation" means that the thickness retardation (Rth) is low, and low retardation is preferable because the phase difference due to birefringence is small.
The residual stress is preferably 26 MPa or less, more preferably 24 MPa or less, still more preferably 20 MPa or less.
The above-mentioned physical property values in the present invention can be specifically measured by the method described in Examples.

[Method for producing imide-amidoic acid copolymer]
The method for producing an imide-amidoic acid copolymer of the present invention includes the following steps 1 and 2.
Step 1: The tetracarboxylic acid component constituting the imide moiety (I) is reacted with the diamine component to obtain an imide oligomer. Step 2: The imide oligomer obtained in Step 1 and the amic acid moiety (A) are formed. A step of reacting the tetracarboxylic acid component to obtain an imide-amide acid copolymer containing a repeating unit consisting of an imide moiety (I) and an amic acid moiety (A) represented by the following formula (1).

（式（１）中、
Ｘ¹は炭素数４〜３９の４価の脂肪族基、脂環基、芳香族基又はこれらの組み合わせからなる基であって、結合基として−Ｏ−、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂−、−Ｃ（ＣＨ₃）₂−、−Ｃ₂Ｈ₄Ｏ−及び−Ｓ−からなる群から選ばれる少なくとも１つを有していてもよい。
Ｘ²はＸ¹とは異なる炭素数４〜３９の４価の脂肪族基、脂環基、芳香族基又はこれらの組み合わせからなる基であって、結合基として−Ｏ−、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂−、−Ｃ（ＣＨ₃）₂−、−Ｃ₂Ｈ₄Ｏ−及び−Ｓ−からなる群から選ばれる少なくとも１つを有していてもよい。
Ｙ¹は炭素数４〜３９の２価の脂肪族基、脂環基、芳香族基又はこれらの組み合わせからなる基であって、結合基として−Ｏ−、−ＳＯ₂−、−ＣＯ−、−ＣＨ₂−、−Ｃ（ＣＨ₃）₂−、−Ｃ₂Ｈ₄Ｏ−及び−Ｓ−からなる群から選ばれる少なくとも１つを有していてもよく、複数のＹ¹は同一の組成を有する。
ｓ及びｔは正の整数である。）

(In equation (1),
X ¹ is a group consisting of a tetravalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and has -O-, -SO _2- , -CO- as a linking group. _{-CH 2 -, - C (CH} 3) 2 -, - it may have at least one member selected from C ₂ H ₄ group consisting of O- and -S-.
X ² is a tetravalent aliphatic group, an alicyclic group, an aromatic group, or combinations of these groups having a carbon number of 4-39, which is different from the X ^1, -O a bonding group -, - SO ₂ - , -CO-, -CH _2- , -C (CH ₃ ) _2- , -C ₂ H ₄ O- and -S- may have at least one selected from the group.
Y ¹ is a group consisting of a divalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and as a linking group, -O-, -SO _2- , -CO-, _{-CH 2 -, - C (CH} 3) 2 -, - it may have at least one member selected from C ₂ H ₄ group consisting of O- and -S-, a plurality of Y ¹ are the same composition Have.
s and t are positive integers. )

According to the method for producing an imide-amide acid copolymer of the present invention, the imide moiety and the amic acid moiety can be controlled to a specific structure, so that the conventional imide moiety and the amic acid moiety are randomly present. Unlike the imide-amide acid copolymer, it is considered that an imide-amide acid copolymer capable of achieving both storage stability and molding processability can be obtained.

Among them, the preferred copolymer of the present invention comprises a tetracarboxylic acid component composed of a compound giving a constituent unit (A-1) and a compound giving a constituent unit (A-2), and a constituent unit (B-1). It can be produced by reacting with a diamine component containing, and is preferably produced by a method having the following steps 1 and 2.
Step 1: The compound giving the structural unit (A-1) is reacted with the compound giving the structural unit (B-1) to obtain an oligomer having an imide repeating structural unit. Step 2: The oligomer obtained in step 1. And the compound giving the structural unit (A-2) are reacted to obtain a copolymer having an imide repeating structural unit and an amic acid structural unit.

That is, the preferred method for producing a copolymer of the present invention is a method for producing a copolymer having the following steps 1 and 2.
The copolymer has a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from diamine.
The structural unit A is a structural unit (A-1) derived from the alicyclic tetracarboxylic dianhydride (a-1) and a tetracarboxylic acid other than the alicyclic tetracarboxylic dianhydride (a-1). Consists of a structural unit (A-2) derived from the dianhydride (a-2)
The structural unit B includes a structural unit (B-1) derived from the compound represented by the formula (b-1).
The structural unit (A-2) is derived from the compound represented by the formula (a-2-1), the structural unit (A-2-1), and the compound represented by the formula (a-2-2). The structural unit (A-2-2), the structural unit derived from the compound represented by the formula (a-2-3) (A-2-3), and the structural unit represented by the formula (a-2-4). It comprises at least one selected from the group consisting of constituent units (A-2-4) derived from the compound.
Step 1: The compound giving the structural unit (A-1) is reacted with the compound giving the structural unit (B-1) to obtain an oligomer having an imide repeating structural unit. Step 2: The oligomer obtained in step 1. And the compound giving the structural unit (A-2) and the compound giving the structural unit B are reacted to obtain a copolymer having an imide repeating structural unit and an amic acid repeating structural unit.

By the manufacturing method having the steps 1 and 2, it is possible to form a film having both storage stability and molding processability, excellent colorless transparency and heat resistance, and excellent low retardation and low residual stress. A copolymer can be produced.
Hereinafter, the method for producing the copolymer of the present invention will be described.

<Step 1>
Step 1 is a step of reacting the tetracarboxylic acid component constituting the imide moiety (I) with the diamine component to obtain an imide oligomer.
Preferably, the tetracarboxylic acid component constituting the imide moiety (I) is an alicyclic tetracarboxylic acid component.
Step 1 is a step of reacting a compound giving a structural unit (A-1) with a compound giving a structural unit (B-1) to obtain an oligomer having an imide repeating structural unit.
The tetracarboxylic acid component used in step 1 preferably contains a compound that gives a constituent unit (A-1), and when the constituent unit (A-1) contains a constituent unit (A-1-1), it is preferable. , It is preferable that the entire amount of the compound giving the structural unit (A-1-1) is used in step 1.
The diamine component used in step 1 preferably contains a compound that gives the constituent unit (B-1), and is a diamine component other than the compound that gives the constituent unit (B-1) as long as the effect of the present invention is not impaired. May include. Examples of such a compound include a compound that gives a structural unit (B-3).
In step 1, the diamine component with respect to the tetracarboxylic acid component is preferably 1.01 to 2 mol, more preferably 1.05 to 1.9 mol, and 1.1 to 1.7 mol. Is even more preferable.

The method for reacting the tetracarboxylic acid component with the diamine component for obtaining the imide oligomer in step 1 is not particularly limited, and a known method can be used.
Specific reaction methods include (1) charging a tetracarboxylic acid component, a diamine component, and a reaction solvent into a reactor, stirring at room temperature (about 20 ° C.) to 80 ° C. for 0.5 to 30 hours, and then ascending. Method of warming to carry out imidization reaction, (2) After charging the diamine component and reaction solvent into the reactor and dissolving them, the tetracarboxylic acid component is charged and, if necessary, at room temperature (about 20 ° C.) to 80 ° C. A method of stirring for 0.5 to 30 hours and then raising the temperature to carry out the imidization reaction. (3) The tetracarboxylic acid component, the diamine component, and the reaction solvent are charged into the reactor, and the temperature is immediately raised to carry out the imidization reaction. And the like.

In the imidization reaction, it is preferable to carry out the reaction while removing water generated during production using a Dean-Stark apparatus or the like. By performing such an operation, the degree of polymerization and the imidization rate can be further increased.

In the above imidization reaction, a known imidization catalyst can be used. Examples of the imidization catalyst include a base catalyst and an acid catalyst.
Base catalysts include pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, tripropylamine, tributylamine, triethylenediamine, imidazole, N, N. Examples thereof include organic base catalysts such as -dimethylaniline and N, N-diethylaniline, and inorganic base catalysts such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium hydrogencarbonate and sodium hydrogencarbonate.
Examples of the acid catalyst include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, oxybenzoic acid, terephthalic acid, benzenesulfonic acid, paratoluenesulfonic acid, naphthalenesulfonic acid and the like. Can be mentioned. The above-mentioned imidization catalyst may be used alone or in combination of two or more.
Of the above, from the viewpoint of handleability, a base catalyst is preferable, an organic base catalyst is more preferable, one or more selected from triethylamine and triethylenediamine is more preferable, and triethylamine is even more preferable.

The temperature of the imidization reaction is preferably 120 to 250 ° C., more preferably 160 to 200 ° C. from the viewpoint of suppressing the reaction rate and gelation. The reaction time is preferably 0.5 to 10 hours after the start of distillation of the produced water.

The imide oligomer obtained in step 1 preferably has an imide repeating structural unit formed from a compound giving a structural unit (A-1) and a compound giving a structural unit (B-1).
Further, the oligomer obtained in step 1 preferably has amino groups at both ends of the main chain of the molecular chain.
By the above method, a solution containing an imide oligomer dissolved in a solvent can be obtained. The solution containing the imide oligomer obtained in step 1 contains at least a part of the components used as the tetracarboxylic acid component and the diamine component in step 1 as unreacted monomers as long as the effects of the present invention are not impaired. You may.

<Process 2>
In step 2 of the production method of the present invention, the imide oligomer obtained in step 1 is reacted with the tetracarboxylic acid component constituting the amic acid moiety (A), and the imide moiety represented by the following formula (1) is used. This is a step of obtaining an imido-amide acid copolymer containing a repeating unit consisting of I) and the amic acid moiety (A).
The tetracarboxylic acid component constituting the amic acid moiety (A) used in step 2 is preferably an aromatic tetracarboxylic acid component, and more preferably contains a compound giving a constituent unit (A-2). It may contain a compound that gives the unit (A-1). However, the tetracarboxylic acid component used in step 2 preferably does not contain a compound that gives a constituent unit (A-1-1). Further, it is preferable that the entire amount of the compound giving the structural unit (A-2) is used in the step 2.
After completion of step 2, in order to introduce the polyorganosiloxane unit into the imide-amide acid copolymer of the present invention, a diamine or tetracarboxylic acid dianhydride containing the polyorganosiloxane unit may be reacted, and the polyorgano may be reacted. It is preferable to react with a diamine containing a siloxane unit, and more preferably to react with a compound giving a constituent unit (B-2).

The method for reacting the tetracarboxylic acid component with the imide oligomer obtained in step 1 for obtaining the imide-amide acid copolymer in step 2 is not particularly limited, and a known method can be used.
As a specific reaction method, (1) the imide oligomer, tetracarboxylic acid component and solvent obtained in step 1 are charged into the reactor, and the temperature is 0 to 120 ° C, preferably 5 to 80 ° C for 1 to 72 hours. Method of stirring, (2) The imide oligomer and solvent obtained in step 1 are charged into a reactor to dissolve them, and then a tetracarboxylic acid component is charged, and the temperature is in the range of 0 to 120 ° C, preferably 5 to 80 ° C. Examples thereof include a method of stirring for ~ 72 hours. When the reaction is carried out at 80 ° C. or lower, the molecular weight of the copolymer obtained in step 2 does not fluctuate depending on the temperature history at the time of polymerization, and the progress of thermal imidization can be suppressed. Can be manufactured stably.

The imide-amidoic acid copolymer obtained by the production method of the present invention is a product of a polyaddition reaction between the tetracarboxylic acid component in step 2, the diamine component in step 2, and the oligomer obtained in step 1.
The imide-amide acid copolymer of the present invention has an imide repeating structural unit formed from a compound giving a structural unit (A-1) and a compound giving a structural unit (B-1) in step 1, and has an imide repeating structural unit. It is preferable to have an amic acid structural unit formed from the compound giving the structural unit (A-2) and the compound giving the structural unit (B-1) in the step 2.

By the above method, a copolymer solution containing an imide-amidoic acid copolymer dissolved in a solvent can be obtained.
The concentration of the copolymer in the obtained copolymer solution is usually 1 to 50% by mass, preferably 3 to 35% by mass, and more preferably 10 to 30% by mass.

The number average molecular weight of the imide-amidoic acid copolymer obtained by the production method of the present invention is preferably 5,000 to 500,000 from the viewpoint of the mechanical strength of the obtained polyimide film. From the same viewpoint, the weight average molecular weight (Mw) is preferably 10,000 to 800,000, more preferably 100,000 to 300,000. The number average molecular weight of the copolymer can be determined from, for example, a standard polymethylmethacrylate (PMMA) conversion value measured by gel filtration chromatography.
Next, the raw materials and the like used in this production method will be described.

<Tetracarboxylic acid component>
The tetracarboxylic acid component used as a raw material for the imide-amide acid copolymer in the present production method is described in (Constituent unit IA) and (Constituent unit AA) of the above <Imido-amide acid copolymer embodiment>. , It is preferable to use a compound that gives each constituent unit. For example, the compound that gives the structural unit (A-1) includes, but is not limited to, the alicyclic tetracarboxylic dianhydride (a-1), and is a derivative thereof within the range that gives the same structural unit. May be good. Examples of the derivative include an alicyclic tetracarboxylic acid corresponding to the alicyclic tetracarboxylic dianhydride (a-1) and an alkyl ester of the alicyclic tetracarboxylic acid. As the compound that gives the structural unit (A-1), an alicyclic tetracarboxylic dianhydride (a-1) is preferable.
Similarly, the compound giving the structural unit (A-2) includes, but is not limited to, tetracarboxylic dianhydride (a-2), and may be a derivative thereof as long as the same structural unit is given. .. Examples of the derivative include a tetracarboxylic acid corresponding to the tetracarboxylic dianhydride (a-2) and an alkyl ester of the tetracarboxylic acid. As the compound that gives the structural unit (A-2), tetracarboxylic dianhydride (a-2) is preferable.

The molar ratio of the compound giving the constituent unit (A-1) to the compound giving the constituent unit (A-2) in the tetracarboxylic acid component used as the raw material of the imide-amide acid copolymer in this production method [( A-1) / (A-2) molar ratio] is preferably 10/90 to 90/10, more preferably 30/70 to 85/15, and even more preferably 50/50 to 80/20. Is.

Examples of the compound that gives the structural unit (A-1) include a compound that gives the structural unit (A-1-1), a compound that gives the structural unit (A-1-2), and a structural unit (A-1--3). The compound to be given is preferable, and the compound to give the structural unit (A-1-1) is more preferable. The total ratio of the compounds giving the structural units (A-1-1) to (A-1--3) to the compounds giving the structural unit (A-1) is preferably 45 mol% or more, more preferably 70. It is mol% or more, more preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the ratio is not particularly limited, that is, it is 100 mol%, and the ratio of the compound giving the structural unit (A-1-1) to the compound giving the structural unit (A-1) is particularly preferable. Is 45 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the ratio is not particularly limited, that is, 100 mol%.
Examples of the compound that gives the structural unit (A-2) include a compound that gives the structural unit (A-2-1), a compound that gives the structural unit (A-2-2), and a structural unit (A-2-3). One or more selected from the group consisting of a compound and a compound giving a structural unit (A-2-4) is preferable. The total ratio of the compounds giving the structural units (A-2-1) to (A-2-4) to the compounds giving the structural unit (A-2) is preferably 45 mol% or more, more preferably 70. It is mol% or more, more preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the ratio is not particularly limited, that is, 100 mol%.
The tetracarboxylic acid component includes a constituent unit (A-1-1), a constituent unit (A-1-2), a constituent unit (A-1--3), a constituent unit (A-2-1), and a constituent unit ( A-2-2), a constituent unit (A-2-3), and a compound other than the compound giving the constituent unit (A-2-4) may be contained, and such a compound may be one kind or two kinds. It may be the above.

<Diamine component>
The compound that gives the structural unit B includes, but is not limited to, a derivative thereof as long as the same structural unit is given. Examples of the derivative include diisocyanates corresponding to diamines. A diamine is preferable as the compound that gives the structural unit B.
For example, as the compound giving the structural unit (B-1), the compound represented by the formula (b-1) (that is, diamine) is preferable. Similarly, as the compound giving the structural unit (B-3), the compound represented by the formula (b-3) (that is, diamine) is preferable.

The diamine component preferably contains a compound that gives the structural unit (B-1) in an amount of 45 mol% or more, more preferably 48 mol% or more, still more preferably 85 mol% or more, still more preferably 88 mol% or more, and preferably 88 mol% or more. Contains 100 mol% or less, more preferably 99.5 mol% or less, still more preferably 99.0 mol% or less. The diamine component may consist only of the compound giving the structural unit (B-1).
When the compound giving the structural unit (B-3) is contained as the diamine component, the compound giving the structural unit (B-3) is preferably 5 to 65 mol%, more preferably 10 to 55 mol% in the total diamine component. , More preferably 25 to 50 mol%.
The diamine component may consist of a combination of one or more selected from the compound giving the structural unit (B-1) and the compound giving the structural unit (B-3).

The total content ratio of the compound giving the structural unit (B-1) and the compound giving the structural unit (B-3) is preferably 45 mol% or more, more preferably 60 mol% or more, still more preferably 60 mol% or more, based on the total diamine components. Is 85 mol% or more. The upper limit of the total content ratio is not particularly limited, that is, 100 mol%.

The diamine component may include a compound that gives a constituent unit (B-1) and a compound that gives a constituent unit B other than a compound that gives a constituent unit (B-3), and examples of such a compound include the above-mentioned aromatic diamine. Examples thereof include alicyclic diamines, aliphatic diamines, and derivatives thereof (diisocyanate, etc.).
The compound other than the compound that gives the structural units (B-1) and (B-3) arbitrarily contained in the diamine component may be one kind or two or more kinds.

When the copolymer contains a compound that gives a structural unit (B-2), a compound that gives the structural unit (B-2) to the total amount of the compound that gives the structural unit (B-2) and the diamine component is used. , Preferably containing 0.01 to 15.0 mol%, more preferably 0.5 to 12.0 mol%, still more preferably 1.0 to 8.0 mol%.

In the present invention, a tetracarboxylic acid used in all steps of producing a copolymer including a reaction step with other components such as a compound giving a constituent unit (B-2) after the completion of steps 1, 2 and 2 is completed. The ratio of the amount of the component to the diamine component charged is preferably 0.9 to 1.1 mol of the diamine component with respect to 1 mol of the tetracarboxylic acid component.

<Terminal sealant>
Further, in the present invention, in addition to the above-mentioned tetracarboxylic acid component and diamine component, an end-capping agent may be used for producing the imide-amidoic acid copolymer. As the terminal encapsulant, monoamines or dicarboxylic acids are preferable. The amount of the terminal encapsulant to be introduced is preferably 0.0001 to 0.1 mol, particularly preferably 0.001 to 0.06 mol, based on 1 mol of the tetracarboxylic acid component. Examples of monoamine terminal encapsulants include methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine, 3-. Ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline and the like are recommended. Of these, benzylamine and aniline can be preferably used. As the dicarboxylic acid terminal encapsulant, dicarboxylic acids are preferable, and a part thereof may be ring-closed. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenonedicarboxylic acid, 3,4-benzophenonedicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1. , 2-Dicarboxylic acid, etc. are recommended. Of these, phthalic acid and phthalic anhydride can be preferably used.

<Solvent>
The solvent used in the method for producing the copolymer of the present invention may be any solvent that can dissolve the produced imide-amide copolymer. For example, an aprotic solvent, a phenol solvent, an ether solvent, a carbonate solvent and the like can be mentioned.

Specific examples of the aprotonic solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethylimidazolidinone, tetramethylurea and the like. Amide solvents, lactone solvents such as γ-butyrolactone and γ-valerolactone, phosphorus-containing amide solvents such as hexamethylphosphoric amide and hexamethylphosphintriamide, and sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide and sulfolane. Examples thereof include a system solvent, a ketone solvent such as acetone, methyl ethyl ketone, cyclohexanone and methylcyclohexanone, and an ester solvent such as acetic acid (2-methoxy-1-methylethyl).

Specific examples of the phenolic solvent include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4. -Xylenol, 3,5-xylenol and the like can be mentioned.
Specific examples of the ether solvent include 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, and bis [2- (2-methoxyethoxy) ethyl]. Examples include ether, tetrahydrofuran, 1,4-dioxane and the like.
Specific examples of the carbonate solvent include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate and the like.
Among the above reaction solvents, an amide solvent or a lactone solvent is preferable, an amide solvent is more preferable, and N-methyl-2-pyrrolidone is further preferable. The above reaction solvent may be used alone or in combination of two or more.

[varnish]
The varnish of the present invention is obtained by dissolving the imide-amidoic acid copolymer of the present invention, which is a precursor of a polyimide resin, in an organic solvent. That is, the varnish of the present invention contains the copolymer of the present invention and an organic solvent, and the copolymer is dissolved in the organic solvent.
The organic solvent is not particularly limited as long as it dissolves the copolymer of the present invention, but the above-mentioned compounds are used alone or in combination of two or more as the solvent used for producing the copolymer of the present invention. It is preferable to use it.
The varnish of the present invention may be the above-mentioned copolymer solution itself, or may be obtained by further adding a diluting solvent to the copolymer solution.

The varnish of the present invention may further contain an imidization catalyst and a dehydration catalyst from the viewpoint of efficiently advancing the imidization of the amic acid moiety in the copolymer of the present invention. The imidization catalyst may be any imidization catalyst having a boiling point of 40 ° C. or higher and 180 ° C. or lower, and an amine compound having a boiling point of 180 ° C. or lower is preferable. If the imidization catalyst has a boiling point of 180 ° C. or lower, the film is not colored when dried at a high temperature after the film is formed, and the appearance is not impaired. Further, if the imidization catalyst has a boiling point of 40 ° C. or higher, the possibility of volatilization before the imidization proceeds sufficiently can be avoided.
Examples of the amine compound preferably used as an imidization catalyst include pyridine and picoline. The above-mentioned imidization catalyst may be used alone or in combination of two or more.
Examples of the dehydration catalyst include acid anhydrides such as acetic anhydride, propionic acid anhydride, n-butyric acid anhydride, benzoic acid anhydride, and trifluoroacetic anhydride; and carbodiimide compounds such as dicyclohexylcarbodiimide. These may be used alone or in combination of two or more.

Since the copolymer contained in the varnish of the present invention has solvent solubility, it can be made into a high-concentration varnish. The varnish of the present invention preferably contains the copolymer of the present invention in an amount of 3 to 40% by mass, more preferably 5 to 40% by mass, and even more preferably 10 to 30% by mass. The viscosity of the varnish is preferably 0.1 to 100 Pa · s, more preferably 0.1 to 20 Pa · s. The viscosity of the varnish is a value measured at 25 ° C. using an E-type viscometer.
Further, the varnish of the present invention has an inorganic filler, an adhesion accelerator, a release agent, a flame retardant, an ultraviolet stabilizer, a surfactant, a leveling agent, an antifoaming agent, and an optical brightener as long as the required properties of the polyimide film are not impaired. Various additives such as an agent, a cross-linking agent, a polymerization initiator, and a photosensitizer may be contained.
The method for producing the varnish of the present invention is not particularly limited, and a known method can be applied.

[Polyimide film]
The polyimide film of the present invention contains a polyimide resin obtained by imidizing the amic acid moiety in the imide-amidoic acid copolymer of the present invention. Therefore, the polyimide film of the present invention can achieve both storage stability and molding processability, is also excellent in colorless transparency and heat resistance, and exhibits low retardation and low residual stress. Suitable physical property values of the polyimide film of the present invention are as described above.
The polyimide film of the present invention can be produced by using a varnish in which the above-mentioned copolymer is dissolved in an organic solvent.

The method for producing a polyimide film using the varnish of the present invention is not particularly limited, and a known method can be used. For example, after the varnish of the present invention is applied or formed into a film on a smooth support such as a glass plate, a metal plate, or a plastic, an organic solvent such as a reaction solvent or a diluting solvent contained in the varnish is heated. A polyimide film is produced by removing it to obtain a copolymer film, imidizing (dehydrating and ring-closing) the amic acid moiety of the copolymer in the copolymer film by heating, and then peeling it from the support. be able to.
The weight average molecular weight (Mw) of the polyimide resin contained in the polyimide film of the present invention is preferably 10,000 to 800,000, more preferably 30,000 to 500,000 from the viewpoint of the mechanical strength of the film. , More preferably 50,000-400,000, 100,000-300,000. The number average molecular weight of the copolymer can be determined from, for example, a standard polymethylmethacrylate (PMMA) conversion value measured by gel filtration chromatography.

The heating temperature for drying the varnish of the present invention to obtain a copolymer film is preferably 50 to 150 ° C. The heating temperature for imidizing the copolymer of the present invention by heating can be preferably selected from the range of 200 to 500 ° C., more preferably 250 to 450 ° C., and even more preferably 300 to 400 ° C. The heating time is usually 1 minute to 6 hours, preferably 5 minutes to 2 hours, and more preferably 15 minutes to 1 hour.
Examples of the heating atmosphere include air gas, nitrogen gas, oxygen gas, hydrogen gas, and nitrogen / hydrogen mixed gas. In order to suppress the coloring of the obtained polyimide resin, nitrogen gas and hydrogen concentration having an oxygen concentration of 100 ppm or less are used. A nitrogen / hydrogen mixed gas containing 0.5% or less is preferable.
The imidization method is not limited to thermal imidization, and chemical imidization can also be applied.

The thickness of the polyimide film of the present invention can be appropriately selected depending on the intended use and the like, but is preferably in the range of 1 to 250 μm, more preferably 5 to 100 μm, and further preferably 7 to 50 μm. When the thickness is 1 to 250 μm, it can be practically used as a self-supporting film.
The thickness of the polyimide film can be easily controlled by adjusting the solid content concentration and viscosity of the varnish.

The polyimide film of the present invention is suitably used as a film for various members such as color filters, flexible displays, semiconductor parts, and optical members. The polyimide film of the present invention is particularly preferably used as a substrate for an image display device such as a liquid crystal display or an OLED display.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to these examples.
The physical characteristics of the films obtained in Examples and Comparative Examples were measured by the methods shown below.

(1) Film thickness The film thickness was measured using a micrometer manufactured by Mitutoyo Co., Ltd.
(2) Moldability Using a spin coater, the varnishes obtained in Examples and Comparative Examples were applied to a glass substrate of 100 mm × 100 mm so that the thickness of the varnish was 100 μm, and the environment was 23 ° C. and 50% RH. Held down. The time until the whitening of the film could be visually confirmed was measured. The longer it takes to start whitening, the better the process and the better the moldability.
(3) Storage stability The varnishes obtained in Examples and Comparative Examples were placed in a glass bottle and stored at 23 ° C. for 1 week. The viscosity of the varnish immediately after production and the viscosity of the varnish after storage for 1 week are measured, and the viscosity of the varnish after storage for 1 week is divided by the viscosity of the varnish immediately after production. ) Was calculated. The smaller the rate of change, that is, the rate of increase in viscosity or the rate of decrease in viscosity, the better the storage stability. The evaluation criteria were A when the rate of change was 10% or less, and B when the rate of change exceeded 10%. The viscosity was measured at 23 ° C. using an E-type viscometer.
(4) Total light transmittance, yellow index (YI)
The total light transmittance and YI were measured in accordance with JIS K7105: 1981 using a color / turbidity simultaneous measuring device "COH400" manufactured by Nippon Denshoku Industries Co., Ltd.
(5) Glass transition temperature (Tg)
Using the thermomechanical analyzer "TMA / SS6100" manufactured by Hitachi High-Tech Science Co., Ltd., the sample size is 3 mm x 20 mm, the load is 0.1 N, under a nitrogen stream (flow rate 200 mL / min), and the temperature rise rate is 10 ° C. in tension mode. Under the condition of / min, the temperature was raised to a temperature sufficient to remove the residual stress to remove the residual stress, and then cooled to room temperature. Then, the elongation of the test piece was measured under the same conditions as the treatment for removing the residual stress, and the place where the inflection point of the elongation was observed was determined as the glass transition temperature.

(6) Thickness phase difference (Rth)
The thickness phase difference (Rth) was measured using an ellipsometer "M-220" manufactured by JASCO Corporation. The value of the thickness phase difference at the measurement wavelength of 590 nm was measured. Rth is expressed by the following formula when the maximum in-plane refractive index of the polyimide film is nx, the minimum is ny, the refractive index in the thickness direction is nz, and the thickness of the film is d. It is a thing.
Rth = [{(nx + ny) / 2} -nz] × d

(7) Residual stress Example using a residual stress measuring device "FLX-2320" manufactured by KLA Tencor Co., Ltd., on a 4-inch silicon wafer having a thickness of 525 μm ± 25 μm for which the “warp amount” has been measured in advance. And the varnish obtained in the comparative example was applied using a spin coater and prebaked. Then, using a hot air dryer, heat curing treatment was performed at 350 ° C. for 30 minutes (heating rate 5 ° C./min) in a nitrogen atmosphere to prepare a silicon wafer with a polyimide film having a thickness of 6 to 20 μm after curing. bottom. The amount of warpage of this wafer was measured using the above-mentioned residual stress measuring device, and the residual stress generated between the silicon wafer and the polyimide film was evaluated.

The tetracarboxylic acid component and diamine component used in Examples and Comparative Examples, and their abbreviations and the like are as follows.
<Tetracarboxylic acid component>
CpODA: Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'', 6,6''-tetracarboxylic dianhydride (manufactured by JX Energy Co., Ltd .; Compound represented by formula (a-1-1))
HPMDA: 1,2,4,5-Cyclohexanetetracarboxylic dianhydride (compound corresponding to alicyclic tetracarboxylic dianhydride (a-1))
s-BPDA: 3,3', 4,4'-biphenyltetracarboxylic dianhydride (manufactured by Mitsubishi Chemical Corporation, compound represented by formula (a-2-1s))
TAHQ: p-phenylenebis (trimeritate) dianhydride (manufactured by Manac Inc., compound represented by formula (a-2-2))
ODPA: 4,4'-oxydiphthalic anhydride (compound represented by formula (a-2-3))
CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride 6FDA: 4,4'-(hexafluoroisopropyridene) diphthalic anhydride <diamine component>
6FODA: 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether (manufactured by ChinaTech (Tianjin) Chemical Co., Ltd., compound represented by formula (b-1))
BAFL: 9,9-bis (4-aminophenyl) fluorene (manufactured by Taoka Chemical Industry Co., Ltd .; compound represented by formula (b-3))
<Other ingredients>
X-22-1660B-3: Both-terminal amino-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., compound represented by the formula (b-2) (functional group equivalent: 2200 g / mol or 2170 g / mol))

The abbreviations of the solvent and catalyst used in Examples and Comparative Examples are as follows.
NMP: N-methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical Corporation)
TEA: Triethylamine (manufactured by Kanto Chemical Co., Inc.)

<Example 1>
32.858 g (0.0977 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel half-moon agitator, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 90.000 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
After adding 22.936 g (0.060 mol) of CpODA and 22.500 g of NMP in a batch to this solution, 0.302 g of TEA was added as an imidization catalyst and heated with a mantle heater over about 20 minutes. The temperature inside the reaction system was raised to 190 ° C. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. Then, 54.435 g of NMP was added to cool the temperature inside the reaction system to 50 ° C. to obtain a solution containing an oligomer having an imide repeating structural unit.
To the obtained solution, 11.704 g (0.040 mol) of s-BPDA and 8.065 g of NMP were added all at once, and the mixture was stirred at 50 ° C. for 5 hours. Then, 107.143 g of NMP was added and homogenized, and then a mixed solution prepared by dissolving 7.723 g (0.002 mol) of X-22-1660B-3 in 17.857 g of NMP was added, and the mixture was further added for about 1 hour. Stirred. Then, NMP was added and homogenized so that the solid content concentration became about 15% by mass to obtain a varnish containing a copolymer having an imide repeating structural unit and an amic acid structural unit.
Subsequently, the obtained varnish is applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. , Polyimide film was obtained. The results are shown in Table 1.
A copolymer having an imide repeating structural unit and an amic acid structural unit as in Example 1 is referred to as "PI-AA".

<Example 2>
26.953 g (0.0802 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel half-moon agitator, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 56.000 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
To this solution, 19.231 g (0.050 mol) of CpODA and 14.000 g of NMP were added all at once, then 0.253 g of TEA was added as an imidization catalyst, and the mixture was heated with a mantle heater over about 20 minutes. The temperature inside the reaction system was raised to 190 ° C. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. Then, 85.806 g of NMP was added to cool the temperature inside the reaction system to 50 ° C. to obtain a solution containing an oligomer having an imide repeating structural unit.
To the obtained solution, 9.814 g (0.033 mol) of s-BPDA and 7.527 g of NMP were added all at once, and the mixture was stirred at 50 ° C. for 5 hours. Then, after adding 100.000 g of NMP to homogenize, a mixed solution prepared by dissolving 14.002 g (0.003 mol) of X-22-1660B-3 in 16.667 g of NMP was added, and the mixture was further stirred for about 1 hour. Then, a varnish containing a copolymer (PI-AA) having a solid content concentration of about 20% by mass was obtained.
Subsequently, the obtained varnish is applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. , Polyimide film was obtained. The results are shown in Table 1.

<Example 3>
25.906 g (0.0746 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel half-moon agitator, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 56.000 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
After adding 18.144 g (0.047 mol) of CpODA and 14.000 g of NMP in a batch to this solution, 0.253 g of TEA was added as an imidization catalyst, and the mixture was heated by a mantle heater over about 20 minutes. The temperature inside the reaction system was raised to 190 ° C. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. Then, 85.806 g of NMP was added to cool the temperature inside the reaction system to 50 ° C. to obtain a solution containing an oligomer having an imide repeating structural unit.
To the obtained solution, 9.259 g (0.0315 mol) of s-BPDA and 7.527 g of NMP were added all at once, and the mixture was stirred at 50 ° C. for 5 hours. Then, after adding 100.000 g of NMP to homogenize, a mixed solution prepared by dissolving 17.502 g (0.004 mol) of X-22-1660B-3 in 16.667 g of NMP was added, and the mixture was further stirred for about 1 hour. Then, a varnish containing a copolymer (PI-AA) having a solid content concentration of about 20% by mass was obtained.
Subsequently, the obtained varnish is applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. , Polyimide film was obtained. The results are shown in Table 1.

<Example 4>
14.806 g (0.044 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , BaFL (15.343 g (0.044 mol)) and NMP (56.000 g) were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
After adding 27.576 g (0.072 mol) of CpODA and 14.000 g of NMP to this solution all at once, 0.363 g of TEA was added as an imidization catalyst, and the mixture was heated with a mantle heater over about 20 minutes. The temperature inside the reaction system was raised to 190 ° C. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. Then, 85.806 g of NMP was added to cool the temperature inside the reaction system to 50 ° C. to obtain a solution containing an oligomer having an imide repeating structural unit.
To the obtained solution, 5.277 g (0.0179 mol) of s-BPDA and 7.527 g of NMP were added all at once, and the mixture was stirred at 50 ° C. for 5 hours. Then, after adding 100.000 g of NMP to homogenize, a mixed solution prepared by dissolving 6.998 g (0.002 mol) of X-22-1660B-3 in 16.667 g of NMP was added, and the mixture was further stirred for about 1 hour. Then, a varnish containing a copolymer (PI-AA) having a solid content concentration of about 20% by mass was obtained.
Subsequently, the obtained varnish is applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. , Polyimide film was obtained. The results are shown in Table 1.

<Example 5>
26.235 g (0.0780 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel half-moon agitator, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 56.000 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
After adding 24.985 g (0.065 mol) of CpODA and 14.000 g of NMP in a batch to this solution, 0.329 g of TEA was added as an imidization catalyst and heated with a mantle heater over about 20 minutes. The temperature inside the reaction system was raised to 190 ° C. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. Then, 85.806 g of NMP was added to cool the temperature inside the reaction system to 50 ° C. to obtain a solution containing an oligomer having an imide repeating structural unit.
To the obtained solution, 4.781 g (0.0163 mol) of s-BPDA and 7.527 g of NMP were added all at once, and the mixture was stirred at 50 ° C. for 5 hours. Then, after adding 100.000 g of NMP to homogenize, a mixed solution prepared by dissolving 13.999 g (0.003 mol) of X-22-1660B-3 in 16.667 g of NMP was added, and the mixture was further stirred for about 1 hour. Then, a varnish containing a copolymer (PI-AA) having a solid content concentration of about 20% by mass was obtained.
Subsequently, the obtained varnish is applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. , Polyimide film was obtained. The results are shown in Table 1.

<Example 6>
26.250 g (0.0781 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel half-moon agitator, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 60.000 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
After adding 18.802 g (0.049 mol) of CpODA and 15.000 g of NMP in a batch to this solution, 0.247 g of TEA was added as an imidization catalyst, and the mixture was heated by a mantle heater over about 20 minutes. The temperature inside the reaction system was raised to 190 ° C. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. Then, 91.135 g of NMP was added to cool the temperature inside the reaction system to 50 ° C. to obtain a solution containing an oligomer having an imide repeating structural unit.
To the obtained solution, 14.946 g (0.0326 mol) of TAHQ and 8.865 g of NMP were added all at once, and the mixture was stirred at 50 ° C. for 5 hours. Then, after adding 218.750 g of NMP to homogenize, a mixed solution prepared by dissolving 15.002 g (0.003 mol) of X-22-1660B-3 in 31.250 g of NMP was added, and the mixture was further stirred for about 1 hour. Then, a varnish containing a copolymer (PI-AA) having a solid content concentration of about 15% by mass was obtained.
Subsequently, the obtained dwanis is applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. , Polyimide film was obtained. The results are shown in Table 1.

<Example 7>
24.408 g (0.0726 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel half-moon agitator, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 60.000 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
After adding 17.738 g (0.046 mol) of CpODA and 15.000 g of NMP to this solution all at once, 0.233 g of TEA was added as an imidization catalyst, and the mixture was heated with a mantle heater over about 20 minutes. The temperature inside the reaction system was raised to 190 ° C. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. Then, 91.135 g of NMP was added to cool the temperature inside the reaction system to 50 ° C. to obtain a solution containing an oligomer having an imide repeating structural unit.
To the obtained solution, 14.101 g (0.0308 mol) of TAHQ and 8.865 g of NMP were added all at once, and the mixture was stirred at 50 ° C. for 5 hours. Then, after adding 218.750 g of NMP to homogenize, a mixed solution prepared by dissolving 18.753 g (0.004 mol) of X-22-1660B-3 in 31.250 g of NMP was added, and the mixture was further stirred for about 1 hour. Then, a varnish containing a copolymer (PI-AA) having a solid content concentration of about 15% by mass was obtained.
Subsequently, the obtained varnish is applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. , Polyimide film was obtained. The results are shown in Table 1.

<Example 8>
34.383 g (0.1023 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel half-moon agitator, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 56.000 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
After adding 23.583 g (0.061 mol) of CpODA and 14.000 g of NMP in a batch to this solution, 0.310 g of TEA was added as an imidization catalyst and heated with a mantle heater over about 20 minutes. The temperature inside the reaction system was raised to 190 ° C. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. Then, 85.806 g of NMP was added to cool the temperature inside the reaction system to 50 ° C. to obtain a solution containing an oligomer having an imide repeating structural unit.
12.034 g (0.0409 mol) of s-BPDA and 7.527 g of NMP were added collectively to the obtained solution, and the mixture was stirred at 50 ° C. for 5 hours. Then, 116.667 g of NMP was added and homogenized to obtain a varnish containing a copolymer (PI-AA) having a solid content concentration of about 20% by mass.
Subsequently, the obtained varnish is applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. , Polyimide film was obtained. The results are shown in Table 1.

<Example 9>
26.694 g (0.0794 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 56.000 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
To this solution, 19.053 g (0.0496 mol) of CpODA and 14.000 g of NMP were added all at once, then 0.251 g of TEA was added as an imidization catalyst, and the mixture was heated with a mantle heater for about 20 minutes. The temperature inside the reaction system was raised to 190 ° C. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. Then, 85.806 g of NMP was added to cool the temperature inside the reaction system to 50 ° C. to obtain a solution containing an oligomer having an imide repeating structural unit.
To the obtained solution, 10.251 g (0.0330 mol) of ODPA and 7.527 g of NMP were added all at once, and the mixture was stirred at 50 ° C. for 5 hours. Then, after adding 100.000 g of NMP to homogenize, a mixed solution prepared by dissolving 14.001 g (0.00323 mol) of X-22-1660B-3 in 16.667 g of NMP was added, and the mixture was further stirred for about 1 hour. Then, a varnish containing a copolymer (PI-AA) having a solid content concentration of about 20% by mass was obtained.
Subsequently, the obtained varnish is applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. , Polyimide film was obtained. The results are shown in Table 1.

<Example 10>
31.535g (0.0938mol) of 6FODA in a 500mL five-necked round-bottom flask equipped with a stainless half-moon stirring blade, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 56.000 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
After adding 13.048 g (0.0582 mol) of HPMDA and 14.000 g of NMP in a batch to this solution, 0.295 g of TEA was added as an imidization catalyst and heated with a mantle heater over about 20 minutes. The temperature inside the reaction system was raised to 190 ° C. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. Then, 85.806 g of NMP was added to cool the temperature inside the reaction system to 50 ° C. to obtain a solution containing an oligomer having an imide repeating structural unit.
11.417 g (0.0388 mol) of s-BPDA and 7.527 g of NMP were added collectively to the obtained solution, and the mixture was stirred at 50 ° C. for 5 hours. Then, after adding 100.000 g of NMP to homogenize, a mixed solution prepared by dissolving 13.999 g (0.00323 mol) of X-22-1660B-3 in 16.667 g of NMP was added, and the mixture was further stirred for about 1 hour. Then, a varnish containing a copolymer (PI-AA) having a solid content concentration of about 20% by mass was obtained.
Subsequently, the obtained varnish is applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. , Polyimide film was obtained. The results are shown in Table 1.

<Example 11>
29.073 g (0.0865 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel half-moon agitator, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 56.000 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
To this solution, 10.343 g (0.0269 mol) of CpODA, 6.032 g (0.0269 mol) of HPMDA, and 14.000 g of NMP were added all at once, and then 0.272 g of TEA was added as an imidization catalyst. It was heated with a mantle heater and the temperature inside the reaction system was raised to 190 ° C. over about 20 minutes. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. Then, 85.806 g of NMP was added to cool the temperature inside the reaction system to 50 ° C. to obtain a solution containing an oligomer having an imide repeating structural unit.
To the obtained solution, 10.556 g (0.0359 mol) of s-BPDA and 7.527 g of NMP were added all at once, and the mixture was stirred at 50 ° C. for 5 hours. Then, after adding 100.000 g of NMP to homogenize, a mixed solution prepared by dissolving 13.998 g (0.00323 mol) of X-22-1660B-3 in 16.667 g of NMP was added, and the mixture was further stirred for about 1 hour. Then, a varnish containing a copolymer (PI-AA) having a solid content concentration of about 20% by mass was obtained.
Subsequently, the obtained varnish is applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. , Polyimide film was obtained. The results are shown in Table 1.

<Example 12>
29.554 g (0.0879 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel half-moon agitator, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 56.000 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
After adding 17.512 g (0.0456 mol) of CpODA and 14.000 g of NMP in a batch to this solution, 0.231 g of TEA was added as an imidization catalyst, heated with a mantle heater, and took about 20 minutes. The temperature inside the reaction system was raised to 190 ° C. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. Then, 85.806 g of NMP was added to cool the temperature inside the reaction system to 50 ° C. to obtain a solution containing an oligomer having an imide repeating structural unit.
To the obtained solution, 8.935 g (0.0456 mol) of CBDA and 7.527 g of NMP were added all at once, and the mixture was stirred at 50 ° C. for 5 hours. Then, after adding 100.000 g of NMP to homogenize, a mixed solution prepared by dissolving 13.999 g (0.00323 mol) of X-22-1660B-3 in 16.667 g of NMP was added, and the mixture was further stirred for about 1 hour. Then, a varnish containing a copolymer (PI-AA) having a solid content concentration of about 20% by mass was obtained.
Subsequently, the obtained varnish is applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. , Polyimide film was obtained. The results are shown in Table 1.

<Example 13>
25.114 g (0.0747 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel half-moon agitator, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 56.000 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
After adding 23.960 g (0.0623 mol) of CpODA and 14.000 g of NMP in a batch to this solution, 0.315 g of TEA was added as an imidization catalyst and heated with a mantle heater over about 20 minutes. The temperature inside the reaction system was raised to 190 ° C. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. Then, 85.806 g of NMP was added to cool the temperature inside the reaction system to 50 ° C. to obtain a solution containing an oligomer having an imide repeating structural unit.
To the obtained solution, 6.923 g (0.0156 mol) of 6FDA and 7.527 g of NMP were added all at once, and the mixture was stirred at 50 ° C. for 5 hours. Then, after adding 100.000 g of NMP to homogenize, a mixed solution prepared by dissolving 14.003 g (0.00323 mol) of X-22-1660B-3 in 16.667 g of NMP was added, and the mixture was further stirred for about 1 hour. Then, a varnish containing a copolymer (PI-AA) having a solid content concentration of about 20% by mass was obtained.
Subsequently, the obtained varnish is applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. , Polyimide film was obtained. The results are shown in Table 1.

<Comparative example 1>
36.293 g (0.1079 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel half-moon agitator, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 59.112 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
To this solution, 24.894 g (0.065 mol) of CpODA, 12.703 g (0.043 mol) of s-BPDA, and 14.778 g of NMP were added all at once, and then 0.546 g of TEA as an imidization catalyst was added. The mixture was charged and heated with a mantle heater, and the temperature inside the reaction system was raised to 190 ° C. over about 20 minutes. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 3 hours while adjusting the rotation speed according to the increase in viscosity.
Then, 201.110 g of NMP was added so that the solid content concentration became about 20% by mass, the temperature in the reaction system was cooled to 100 ° C., and then stirred for about 1 hour to homogenize the polyimide (PI). I got a varnish.
Subsequently, the obtained polyimide varnish was applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. To obtain a polyimide film. The results are shown in Table 1.

<Comparative example 2>
32.662 g (0.097 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 130.667 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
To this solution, 37.338 g (0.097 mol) of CpODA and 32.667 g of NMP were added all at once, and the mixture was stirred at room temperature for 5 hours.
Then, 116.667 g of NMP was added so that the solid content concentration became about 20% by mass, and the mixture was further stirred for about 1 hour to homogenize to obtain a polyamic acid (PAA) varnish.
Subsequently, the obtained polyamic acid varnish was applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to remove the solvent. Although it was evaporated, the entire surface of the film had cracks and could not be measured. The results are shown in Table 1.

<Comparative example 3>
33.828 g (0.101 mol) of 6FODA in a 500 mL five-necked round-bottom flask equipped with a stainless steel half-moon agitator, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 92.657 g of NMP were added, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
After adding 23.613 g (0.061 mol) of CpODA and 23.164 g of NMP in a batch to this solution, 0.311 g of TEA was added as an imidization catalyst and heated with a mantle heater over about 20 minutes. The temperature inside the reaction system was raised to 190 ° C. The components to be distilled off are collected, the rotation speed is adjusted according to the increase in viscosity, the temperature inside the reaction system is maintained at 190 ° C., and the mixture is refluxed for 1 hour to obtain a solution containing an oligomer having an imide repeating structural unit. rice field.
Then, 51.114 g of NMP was added to cool the temperature inside the reaction system to 50 ° C., then 12.050 g (0.041 mol) of s-BPDA and 8.065 g of NMP were added all at once and 1 at 50 ° C. Stirred for hours. Then, 107.143 g of NMP was added to homogenize, and then a mixed solution prepared by dissolving 7.723 g (0.002 mol) of X-22-1660B-3 in 17.857 g of NMP was added, and the mixture was further stirred for about 1 hour. bottom. It was heated with a mantle heater and the temperature inside the reaction system was raised to 190 ° C. over about 20 minutes. The components to be distilled off were collected, and the temperature inside the reaction system was maintained at 190 ° C. and refluxed for 3 hours while adjusting the rotation speed according to the increase in viscosity.
Then, 125.000 g of NMP was added so that the solid content concentration became about 15% by mass, the temperature in the reaction system was cooled to 100 ° C., and then the mixture was further stirred for about 1 hour to homogenize to obtain a polyimide varnish. rice field.
Subsequently, the obtained polyimide varnish was applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to evaporate the solvent. To obtain a polyimide film. The results are shown in Table 1.
The polyimide obtained in Comparative Example 3 has an imide repeating structural unit formed from CpODA and 6FODA, and has an imide structural unit formed from s-BPDA and 6FODA. The polyimide is referred to as "PI-I".

<Comparative Example 4>
37.333g (0.111mol) of 6FODA in a 500mL five-necked round-bottom flask equipped with a stainless steel half-moon stirring blade, a nitrogen inlet tube, a Dean Stark with a cooling tube, a thermometer, and a glass end cap. , And 130.667 g of NMP were added, and the mixture was stirred at a system temperature of 50 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
32.667 g (0.111 mol) of s-BPDA and 32.667 g of NMP were added collectively to this solution, and the mixture was stirred at room temperature for 5 hours.
Then, 116.667 g of NMP was added so that the solid content concentration became about 20% by mass, and the mixture was further stirred for about 1 hour to homogenize to obtain a polyamic acid (PAA) varnish.
Subsequently, the obtained polyamic acid varnish was applied onto a glass plate by spin coating, held on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 350 ° C. for 30 minutes in an air atmosphere to remove the solvent. Evaporation gave a polyimide film. The results are shown in Table 1.
The polyamic acid obtained in Comparative Example 4 has only an amic acid repeating structural unit formed from s-BPDA and 6FODA. The polyamic acid is referred to as "PAA".

It can be seen that the imide-amidoic acid copolymer of the example can achieve both storage stability and molding processability.
Further, as shown in Table 1, the polyimide films of Examples 1 to 16 formed from a polymer having a specific imide repeating structural unit and an amic acid structural unit are excellent in colorless transparency and heat resistance, and further low. It was excellent in polyimide and low residual stress.

Claims (23)

An imide-amide acid copolymer containing a repeating unit composed of an imide moiety (I) and an amic acid moiety (A) represented by the following formula (1).

(In equation (1),
X ¹ is a group consisting of a tetravalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and has -O-, -SO _2- , -CO- as a linking group. _{-CH 2 -, - C (CH} 3) 2 -, - it may have at least one member selected from C ₂ H ₄ group consisting of O- and -S-.
X ² is a tetravalent aliphatic group, an alicyclic group, an aromatic group, or combinations of these groups having a carbon number of 4-39, which is different from the X ^1, -O a bonding group -, - SO ₂ - , -CO-, -CH _2- , -C (CH ₃ ) _2- , -C ₂ H ₄ O- and -S- may have at least one selected from the group.
Y ¹ is a group consisting of a divalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and as a linking group, -O-, -SO _2- , -CO-, _{-CH 2 -, - C (CH} 3) 2 -, - it may have at least one member selected from C ₂ H ₄ group consisting of O- and -S-, a plurality of Y ¹ are the same composition Have.
s and t are positive integers. ) The imide-amidoic acid copolymer according to claim 1, wherein the s is 1 to 20. The imide-amidoic acid copolymer according to claim 1 or 2, wherein t is 5 to 200. The imide-amide acid copolymer according to any one of claims 1 to 3, wherein Y ¹ is a divalent aromatic group having 4 to 39 carbon atoms, a diaminoalkylcyclohexane or a group thereof. Combined. The imide-amidic acid co-weight according to any one of claims 1 to 4, wherein X ¹ is a group consisting of a tetravalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, or a combination thereof. Combined. The imide-amide acid copolymer according to any one of claims 1 to 5, wherein X ^{2 is a tetravalent aromatic group having 4 to 39 carbon atoms.} The imide moiety (I) has a structural unit IA derived from a tetracarboxylic dianhydride and a structural unit IB derived from a diamine.
The amic acid moiety (A) has a structural unit AA derived from tetracarboxylic dianhydride and a structural unit AB derived from diamine.
Constituent unit IA comprises a structural unit (A-1) derived from alicyclic tetracarboxylic dianhydride (a-1).
The imide-amide acid copolymer according to any one of claims 1 to 6, wherein the structural unit IB and the structural unit AB contain a structural unit derived from an aromatic diamine having an ether bond. The imide moiety (I) has a structural unit IA derived from a tetracarboxylic dianhydride and a structural unit IB derived from a diamine.
The amic acid moiety (A) has a structural unit AA derived from tetracarboxylic dianhydride and a structural unit AB derived from diamine.
Constituent unit IA comprises a structural unit (A-1) derived from alicyclic tetracarboxylic dianhydride (a-1).
The imide-amide acid copolymer according to any one of claims 1 to 6, wherein the structural unit IB and the structural unit AB contain a structural unit derived from a fluorine-containing aromatic diamine. The imide-amide acid copolymer according to claim 7 or 8, wherein the structural unit IB and the structural unit AB include a structural unit (B-1) derived from a compound represented by the following formula (b-1).

Constituent unit AA comprises a structural unit (A-2) derived from tetracarboxylic dianhydride (a-2).
The structural unit (A-2) is derived from the compound represented by the following formula (a-2-1), the structural unit (A-2-1), and the compound represented by the following formula (a-2-2). Constituent unit derived from (A-2-2), structural unit derived from a compound represented by the following formula (a-2-3) (A-2-3), and the following formula (a-2-4). The imide-amide acid copolymer according to any one of claims 7 to 9, which comprises at least one selected from the group consisting of the structural unit (A-2-4) derived from the compound represented by.

The imide-amide acid copolymer according to any one of claims 7 to 10, further comprising a structural unit (B-2) derived from a compound represented by the following formula (b-2).

(In the formula (b-2), Z ¹ and Z ² each independently represent a divalent aliphatic group or a divalent aromatic group, and R ¹ and R ² each independently represent a monovalent aromatic group. Or monovalent aliphatic groups, R ³ and R ⁴ independently represent monovalent aliphatic groups, and R ⁵ and R ⁶ independently represent monovalent aliphatic groups or monovalent aromatic groups, respectively. Indicates a group, m and n each independently represent an integer of 1 or more, and the sum of m and n represents an integer of 2 to 1000, provided that ^{at least one of R 1} and R ² is a monovalent aromatic group. Shows.) The imide-amide acid copolymer according to claim 11, wherein R ¹ and R ² are phenyl groups, and R ³ and R ^{4 are methyl groups.} The imide-amide acid copolymer according to claim 11 or 12, wherein the content of the polyorganosiloxane unit in the imide-amide acid copolymer is 5 to 45% by mass. The structural unit (A-1) is a structural unit (A-1-1) derived from a compound represented by the following formula (a-1-1), and a compound represented by the following formula (a-1-2). At least one selected from the group consisting of the structural unit (A-1-2) derived from and the structural unit (A-1--3) derived from the compound represented by the following formula (a-1-3). The imide-amidoic acid copolymer according to any one of claims 7 to 13, which comprises.

The imide-according to any one of claims 7-14, wherein the structural unit IB and the structural unit AB further include a structural unit (B-3) derived from a compound represented by the following formula (b-3). Amidoic acid copolymer.

(In formula (b-3), R independently represents a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms.) A varnish in which the copolymer according to any one of claims 1 to 15 is dissolved in an organic solvent. A polyimide film containing a polyimide resin obtained by imidizing an amic acid moiety in the copolymer according to any one of claims 1 to 15. The polyimide film according to claim 17, wherein the polyimide resin has a weight average molecular weight (Mw) of 100,000 to 300,000. A method for producing an imide-amidoic acid copolymer, which comprises the following steps 1 and 2.
Step 1: The tetracarboxylic acid component constituting the imide moiety (I) is reacted with the diamine component to obtain an imide oligomer. Step 2: The imide oligomer obtained in Step 1 and the amic acid moiety (A) are formed. A step of reacting the tetracarboxylic acid component to obtain an imide-amide acid copolymer containing a repeating unit consisting of an imide moiety (I) and an amic acid moiety (A) represented by the following formula (1).

(In equation (1),
X ¹ is a group consisting of a tetravalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and has -O-, -SO _2- , -CO- as a linking group. _{-CH 2 -, - C (CH} 3) 2 -, - it may have at least one member selected from C ₂ H ₄ group consisting of O- and -S-.
X ² is a tetravalent aliphatic group, an alicyclic group, an aromatic group, or combinations of these groups having a carbon number of 4-39, which is different from the X ^1, -O a bonding group -, - SO ₂ - , -CO-, -CH _2- , -C (CH ₃ ) _2- , -C ₂ H ₄ O- and -S- may have at least one selected from the group.
Y ¹ is a group consisting of a divalent aliphatic group having 4 to 39 carbon atoms, an alicyclic group, an aromatic group or a combination thereof, and as a linking group, -O-, -SO _2- , -CO-, _{-CH 2 -, - C (CH} 3) 2 -, - it may have at least one member selected from C ₂ H ₄ group consisting of O- and -S-, a plurality of Y ¹ are the same composition Have.
s and t are positive integers. ) The method for producing an imide-amide acid copolymer according to claim 19, wherein the imide oligomer obtained in step 1 has amino groups at both ends of the main chain of the molecular chain. The method for producing an imide-amide acid copolymer according to claim 19 or 20, wherein in step 1, the molar ratio of the diamine component to the tetracarboxylic acid component (diamine / tetracarboxylic acid) is 1.01 to 2. The tetracarboxylic acid component constituting the imide moiety (I) used in step 1 is an alicyclic tetracarboxylic acid component, and the tetracarboxylic acid component constituting the amic acid moiety (A) used in step 2 is aromatic. The method for producing an imide-amidic acid copolymer according to any one of claims 19 to 21, which is a group tetracarboxylic acid component. The method for producing an imide-amide acid copolymer according to any one of claims 19 to 22, wherein a diamine containing a polyorganosiloxane unit is reacted after the completion of step 2.