JP7407501B2 - polyimide laminate - Google Patents

Description

The present invention relates to a polyimide laminate having a polyimide layer and a resin layer adjacent to the polyimide layer, and particularly to a polyimide laminate having excellent interlayer adhesion between a polyimide layer and an adjacent resin layer. Regarding.

Conventionally, polyimide, which has excellent heat resistance, electrical insulation properties, abrasion resistance, chemical resistance, mechanical properties, etc., has been widely used in the fields of electricity, electronic parts, transportation equipment, space, aircraft, etc. In insulating coatings, which are a typical use of polyimide, as the performance of final products increases, even higher performance is required of insulating resins. For example, in the case of flexible printed circuit boards (FPC), as devices become smaller, not only is the insulation coating required to be thinner in order to make the FPC thinner, but also high flexibility is required in order to fit it into the device housing. Therefore, the insulating coating is required to have mechanical strength to achieve sufficient durability even if it is a thin film, and flexibility to prevent breakage when bent. Insulating coatings in display panels need to be as flexible as insulating coatings for FPCs in order to make displays thinner and more flexible, and they also need to have high mechanical strength in order to withstand contact with touch pens and the like. Furthermore, the insulation coating materials for various electric wires used in automobiles have high heat resistance due to the higher output of automobiles, and high flexibility to cope with the bending of electric wires and friction between wires due to higher wiring density. Mechanical strength is required.

For example, enamelled wire used in motor coils (magnet wires, wire harnesses, etc.) is insulated, highly heat resistant, and undergoes harsh coil forming to meet motor performance demands such as smaller size, lighter weight, and higher heat resistance. A polyimide resin-coated enameled wire that has mechanical properties that can withstand the above is used (Patent Document 1).

Japanese Patent Application Publication No. 2011-29100

When forming a thick insulating film on a substrate, coil, etc. using polyimide resin, problems such as foaming occur when trying to form a thick insulating film with only one coating and baking process. Therefore, it is not possible to form an insulating film that satisfies the required characteristics.
Therefore, in order to form a thick insulating film, it is necessary to repeat the film forming steps of coating and baking multiple times. However, when the film forming process is performed multiple times in this way, there is a drawback that the interlayer adhesion between the polyimide layer formed first and the polyimide layer formed in the next film forming process is poor, and the layers are likely to peel off. Furthermore, due to poor interlayer adhesion, solvents may enter between the layers, resulting in poor solvent resistance.

This poor interlayer adhesion is due to the rigid structure of the polyimide resin, and the polyimide molecules on the surface of the previously formed polyimide layer do not move easily, making it difficult for the coating liquid to form the next polyimide layer on this surface. This is because the coating liquid does not fully adapt to the surface of the underlying polyimide layer when it is applied. This poor interlayer adhesion occurs not only when a polyimide layer is formed on a polyimide layer, but also when a resin layer other than a polyimide resin layer is formed on a polyimide layer.

To solve this problem, it is possible to add additives to improve interlayer adhesion, but polyimide resin and/or its precursor polyamic acid require a high firing temperature during film formation, and ordinary resins Common additives used to form layers cannot be used.

The present invention solves the above problems, and an object of the present invention is to provide a polyimide laminate having a polyimide layer and a resin layer adjacent to the polyimide layer, the polyimide laminate having a polyimide layer and a resin layer adjacent to the polyimide layer. An object of the present invention is to provide a polyimide laminate having excellent interlayer adhesion.

The present inventors conducted extensive research to solve the above problems, and found that by adding a polymer having a heterocyclic side chain to the polyimide layer, the interlayer adhesion between the polyimide layer and the adjacent resin layer was improved. We have discovered that this can be done, and have arrived at the present invention.
That is, the gist of the present invention is as follows.

[1] A polyimide laminate having a polyimide layer and a resin layer adjacent to the polyimide layer, the polyimide layer containing a polymer having a heterocycle in a side chain.

[2] The polymer having a heterocycle in the side chain is one or more selected from the group consisting of polyvinylpyrrolidone, polyvinylpyridine, and copolymers containing vinylpyrrolidone and/or vinylpyridine as a copolymerization component. The polyimide laminate according to [1].

[3] The polyimide laminate according to [1] or [2], wherein the polyimide resin contained in the polyimide layer has a glass transition temperature (Tg) of 250 to 400°C.

[4] Any of [1] to [3], wherein the polyimide resin contained in the polyimide layer has at least one of a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2). The polyimide laminate described in the above.

[5] The polyimide laminate according to any one of [1] to [4], wherein the polyimide resin contained in the polyimide layer has a structural unit represented by the following formula (3).

(In the above formula (3), R ¹ to R ⁸ may be the same or different from each other, and include a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, or a hydroxyl group) , X is a direct bond, an oxygen atom, a sulfur atom, an alkylene group having 1 to 4 carbon atoms, a sulfonyl group, a sulfinyl group, a sulfide group, a carbonyl group, an ester group, or a secondary amino group, and n is 0 to 4. ).

[6] The polyimide resin contained in the polyimide layer has a repeating unit containing a structure represented by the following formula (5), -NH-, =NH, -C(O)NH-, -NHC(O)O -, -NHC(O)NH-, -NHC(S)NH-, -NH ₂ , -OH, -C(O)OH, -SH, -C(O)N(OH)-, -(O) and a repeating unit containing at least one type of structure selected from the group consisting of S(O)-, -C(O)-, and -C(O)SH, according to any one of [1] to [5]. polyimide laminate.

(In the above formula (5), R ^a represents a tetracarboxylic acid residue, and R ^b represents a diamine residue.)

[7] The polyimide resin contained in the polyimide layer has a repeating unit including a structure represented by the formula (5) and a repeating unit including a -C(O)NH- structure. polyimide laminate.

[8] The polyimide laminate according to [7], wherein the -C(O)NH- structure is derived from 4,4'-diaminobenzanilide.

[9] The polyimide laminate according to any one of [1] to [8], wherein the molecular terminals of the polyimide resin contained in the polyimide layer are sealed.

[10] The polyimide laminate according to any one of [1] to [9], wherein the polyimide layer has a thickness of 0.1 to 100 μm.

[11] A metal-polyimide laminate obtained by coating a metal base material with the polyimide laminate according to any one of [1] to [10].

[12] A magnet wire formed by covering a metal wire with the polyimide laminate according to any one of [1] to [10].

[13] A polyimide resin composition for forming the polyimide layer of the polyimide laminate according to any one of [1] to [10], wherein the polyimide resin composition is based on 100 parts by weight of the polyimide resin and/or its precursor. A resin composition containing 0.1 to 7 parts by weight of a polymer having a heterocycle in its side chain.

According to the present invention, there is provided a polyimide laminate having a polyimide layer and a resin layer adjacent to the polyimide layer, which has excellent interlayer adhesion between the polyimide layer and the adjacent resin layer. .

Embodiments of the present invention will be described in detail below, but the following description is an example of the embodiments of the present invention, and the present invention is limited to the following description unless it exceeds the gist thereof. isn't it. Note that when the expression "~" is used in this specification, it is used as an expression that includes numerical values or physical property values before and after it.

The polyimide laminate of the present invention is a polyimide laminate having a polyimide layer and a resin layer adjacent to the polyimide layer, and is characterized in that the polyimide layer contains a polymer having a heterocycle in a side chain. It is something.

The polyimide laminate of the present invention may have at least one polyimide layer and a resin layer adjacent to this polyimide layer, and is not limited to a two-layer laminate structure of a polyimide layer and an adjacent resin layer, but may have a three-layer structure. The above laminated structure may be used. Further, the adjacent resin layer is not limited to a polyimide layer, but may be a layer formed of a resin other than polyimide resin.
Here, one polyimide layer or resin layer refers to a layer formed in one film forming process, for example, by heating a coating film formed by applying the resin composition of the present invention described below. The polyimide layer formed by performing the film forming process is referred to as "one polyimide layer". When the resin composition of the present invention or another resin composition for forming a resin layer is applied again on this polyimide layer and a heating step is performed, a laminate of two polyimide layers or a single polyimide layer is formed. It is called a laminate of one resin layer.

The polyimide layer according to the present invention may be any layer as long as it contains a polymer having a heterocycle in the side chain, and there is no particular restriction on the method of forming it. It is formed using a resin composition to which a predetermined amount of a polymer having a heterocycle is added (hereinafter, this resin composition may be referred to as "the resin composition of the present invention") as a coating liquid. Note that the polyimide varnish may contain polyamic acid (however, in a smaller amount than polyimide), and the polyamic acid varnish may contain polyimide (however, in a smaller amount than polyamic acid).

[Mechanism of action]
The mechanism by which the interlayer adhesion between the polyimide layer and the adjacent resin layer can be improved by containing a polymer having a heterocycle in the side chain in the polyimide layer is as follows.

That is, as mentioned above, the poor interlayer adhesion between the polyimide layer and the adjacent resin layer is due to the low mobility of polyimide molecules, which makes it difficult for molecular chains to entangle or chemically bond. When a polymer having a heterocycle is included, the hydrophilicity and molecular mobility of the interface are improved, and interlayer adhesion can be enhanced. This is because polymers with heterocycles in their side chains, such as polyvinylpyrrolidone, have a similar structure to N-methylpyrrolidone (NMP), which is commonly used as a solvent for polyimide resins. Polymers that are easily compatible with coating liquids and have heterocycles in their side chains are similar to the imide ring structure of polyimide resins, further improving the compatibility between coating liquids and polyimide layers and improving interlayer adhesion. This is thought to be due to the

Heat resistance, bending resistance, and abrasion resistance as an insulation coating resin are required not only for insulation coating resin applications for enameled wires, but also for polyimide resins used to form insulation coatings on flexible display substrates, for example. By including a polymer having a heterocycle in the side chain, it is also possible to obtain the effect that the bending resistance (bending followability) can be improved while maintaining the heat resistance of the polyimide resin. The details of the reason are not clear, but polymers with heterocycles in their side chains, such as polyvinylpyrrolidone, tend to coordinate between the molecules of polyimide resin, and by coordinating between the molecules of polyimide resin, It is presumed that this is due to the strong intermolecular force between polyimide molecules becoming weaker and the mobility of polyimide molecules improving.
In addition, by introducing a hydrogen bond forming structure described below into the polyimide resin, the wear resistance can be improved, and by further sealing the ends of the polyimide resin, the bending resistance can be improved.

[Polyimide resin]
First, the polyimide resin forming the polyimide layer of the polyimide laminate of the present invention will be explained.

Polyimide resin can usually be obtained by using tetracarboxylic dianhydride and a diamine compound as raw materials to obtain a polyamic acid (polyimide precursor) and then imidizing the polyamic acid. A polyimide resin can also be produced directly from a dianhydride and a diamine compound by imidization reaction.

Examples of the tetracarboxylic dianhydride include chain aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride, and the like. One type of these compounds may be used alone, or two or more types may be used in any ratio and combination.

Examples of chain aliphatic tetracarboxylic dianhydrides include ethylenetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, meso-butane-1,2,3,4-tetracarboxylic dianhydride, and the like. can be mentioned.

Examples of the alicyclic tetracarboxylic dianhydride include 3,3',4,4'-biscyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1 , 2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4 -Cyclobutanetetracarboxylic dianhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-11,2-dicarboxylic anhydride, tricyclo[6.4.0.0 ^{2, 7} ] Dodecane-1,8:2,7-tetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 4- (2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, 1,1'-bicyclohexane-3,3',4,4 '-tetracarboxylic dianhydride and the like.

Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, and 1,1-bis(2,3-dicarboxyphenyl). Ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride Anhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, bis(3,4-dicarboxyphenyl) ) Sulfone dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, 4,4-(p-phenylenedioxy)diphthalic dianhydride, 4,4-(m-phenylenedioxy)diphthalic dianhydride, 2,2',6,6'-biphenyltetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)- 1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride Anhydride, 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyltetracarboxylic dianhydride, 4,4'-(hexafluorotrimethylene)-diphthalic dianhydride , 4,4'-(octafluorotetramethylene)-diphthalic dianhydride, 4,4'-oxydiphthalic anhydride, 1,2,5,6-naphthalene dicarboxylic dianhydride, 1,4,5, 8-naphthalene dicarboxylic dianhydride, 2,3,6,7-naphthalene dicarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetra Examples include carboxylic dianhydride and 1,2,7,8-phenanthrenetetracarboxylic dianhydride.

Examples of the diamine compound include aromatic diamine compounds, chain aliphatic diamine compounds, alicyclic diamine compounds, and the like. One type of these compounds may be used alone, or two or more types may be used in any ratio and combination.

Examples of aromatic diamine compounds include 1,4-phenylenediamine, 1,2-phenylenediamine, 1,3-phenylenediamine, 4,4'-(biphenyl-2,5-diylbisoxy)bisaniline, 4, 4'-Diamino diphenyl ether, 3,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 2,2-bis(4-(4 -aminophenoxy)phenyl)propane, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, 1,3-bis(4-aminophenoxy)neopentane, 4 , 4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-diamino- 3,3'-dihydroxybiphenyl, bis(4-amino-3-carboxyphenyl)methane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfide, N- (4-aminophenoxy)-4-aminobenzamine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, bis(3-aminophenyl)sulfone, norbornanediamine, 4,4'- Diamino-2-(trifluoromethyl)diphenyl ether, 5-trifluoromethyl-1,3-benzenediamine, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 4,4'-diamino -2,2'-bis(trifluoromethyl)biphenyl, 2,2-bis[4-{4-amino-2-(trifluoromethyl)phenoxy}phenyl]hexafluoropropane, 2-trifluoromethyl-p- phenylenediamine, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 4,4'-(9-fluorenylidene)dianiline, 2,7-diaminofluorene, 1,5-diaminonaphthalene, and 3 , 7-diamino-2,8-dimethyldibenzothiophene 5,5-dioxide and the like.

Examples of chain aliphatic diamine compounds include 1,2-ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-hexamethylenediamine, and 1,5-diaminopropane. Examples include diaminopentane, 1,10-diaminodecane, 1,2-diamino-2-methylpropane, 2,3-diamino-2,3-butanediamine, and 2-methyl-1,5-diaminopentane.

Examples of the alicyclic diamine compound include 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and 4,4'-methylenebis(2-methylcyclohexylamine).

<Other ingredients>
In the production of polyimide resin, depending on the purpose, compounds having ethynyl groups, vinyl groups, allyl groups, cyano groups, isocyanate groups, etc. that serve as crosslinking points (hereinafter sometimes referred to as "other monomers") may be added. May be used.

<Preferable aspect 1>
From the viewpoint of heat resistance and productivity, the polyimide resin used in the present invention preferably has at least one of a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2).

The structural units represented by the above formulas (1) and (2) may be derived from tetracarboxylic dianhydride or from a diamine compound, but usually tetracarboxylic acid Introduced into polyimide resins by dianhydrides. Therefore, the polyimide resin used in the present invention uses at least pyromellitic dianhydride and/or 3,3',4,4'-biphenyltetracarboxylic dianhydride as the raw material tetracarboxylic dianhydride. Preferably, it is a manufactured product.

Furthermore, from the viewpoint of heat resistance, the polyimide resin used in the present invention preferably has a structural unit represented by the following formula (3).

In the above formula (3), R ¹ to R ⁸ may be the same or different, and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, or a hydroxyl group. be. Among these, a hydrogen atom or a methyl group is preferred.

In the above formula (3), be. Among these, a direct bond, an oxygen atom, a sulfur atom, an alkylene group having 1 to 4 carbon atoms, a sulfonyl group, or an amide group are preferred, and an oxygen atom and/or an amide group are particularly preferred.

In the above formula (3), n is an integer from 0 to 4. n is preferably an integer from 1 to 4.

In addition, in the structural unit represented by formula (3) in one polyimide molecule as a whole, R ¹ to R ⁸ , X, and n do not necessarily all have to be the same. In particular, when n is an integer greater than or equal to 2, X may have a different structure.

Among the structural units represented by formula (3), those represented by any of the following formulas (3-1) to (3-6) are preferred. Note that one molecule of polyimide may contain only one type of these structural units or a combination of multiple types.

The structural unit represented by the above formula (3) may be derived from a tetracarboxylic dianhydride or a diamine compound, but it is usually introduced into the polyimide resin by a diamine compound. Ru.

Therefore, the polyimide resin used in the present invention is preferably manufactured using at least a diamine compound represented by the following formula (4) as the diamine compound.

In the above formula (4), R ¹ ' to R ⁸ ' are defined in the same way as R ¹ to R ⁸ in the above formula (3), and X' is defined in the same way as X. Further, n' is defined similarly to n.

Examples of the diamine compound represented by the above formula (4) include 4,4'-diaminodiphenyl ether, 2,2'-dimethyl-4,4'-diaminobiphenyl, 1,4-bis(4-aminophenoxy) Benzene, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 2,2-bis[4-(4 -aminophenoxy)phenyl]propane, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-diaminobenzoylanilide , 4-aminophenyl-4-aminobenzoate, bis(4-aminophenyl) terephthalate, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-amino-3-carboxyphenyl)methane, etc. . Among these, 4,4'-diaminodiphenyl ether, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl and the like are preferred.

The polyimide resin used in the present invention may have a structural unit other than the structural unit represented by the above formula (1) or (2) and the structural unit represented by the above formula (3), but the polyimide resin may have a structural unit other than the structural unit represented by the above formula (3). In order to effectively obtain the above-mentioned effects of the structural unit represented by (1) or (2) and the structural unit represented by formula (3), Contains 80 mol% or more, especially 90 to 100 mol%, of the structural units represented by formulas (1) and/or (2) in the total structural units, and contains the structural units derived from the diamine compound constituting the polyimide resin. It is preferable that the structural unit represented by formula (3) is contained in an amount of 80 mol % or more, particularly 90 to 100 mol %.

When the polyimide resin used in the present invention has both the structural unit represented by the formula (1) and the structural unit represented by the formula (2), the proportion thereof is not particularly limited. Preferably, the structural unit represented by the formula (1) is 50 mol% or more based on the total of 100 mol% of the structural unit represented by the formula (1) and the structural unit represented by the formula (2). It is preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95% or more. Within the above range, bending resistance tends to improve.

<Preferred aspect 2>
From the viewpoint of heat resistance, abrasion resistance, and bending resistance, the polyimide resin used in the present invention has a repeating unit containing a structure represented by the following formula (5) and -NH- (imino bond; also referred to as an imino group). ), =NH (imino group), -C(O)NH- (amide bond; sometimes called amide group), -NHC(O)O- (urethane bond; sometimes called urethane group), -NHC(O)NH- (urea bond; sometimes called urea group), -NHC(S)NH- (thiourea bond; sometimes called thiourea group), -NH ₂ (amino group), -OH (hydroxyl group), -C(O)OH (carboxy group), -SH (thiol group), -C(O)N(OH)- (hydroxyamide group), -(O)S(O)-(sulfonyl group) ), -C(O)- (carbonyl group), and -C(O)SH (thiocarboxy group) (hereinafter, these structures will be referred to as "hydrogen bond forming structures") ) is preferable.

(In the formula, R ^a represents a tetracarboxylic acid residue (i.e., a structural unit derived from a tetracarboxylic dianhydride), and R ^b represents a diamine residue (i.e., a structural unit derived from a diamine compound).)

This is due to the following reasons.
It is known that connecting molecular chains with chemical bonds increases the elastic modulus. Chemical bonds include covalent bonds and non-covalent bonds, but when molecular chains are linked by covalent bonds, the elastic modulus increases (that is, wear resistance improves), but mechanical flexibility (elongation) increases. ) decreases. That is, the bending resistance decreases. Normally, when polyimide resin or polyamic acid is fired above a certain temperature, the ends of the molecules react with other molecules or specific sites within the molecule to form covalent bonds, which reduces flexibility, but the molecular By having a repeating unit that includes a structure that forms a non-covalent bond, a non-covalent bond (hereinafter sometimes simply referred to as a "non-covalent bond") is formed with a specific site between molecules and/or within a molecule, It has an appropriate elastic modulus due to intermolecular interactions, and can have both wear resistance and bending resistance.

Non-covalent bonds include ionic bonds, π-π stacking, hydrogen bonds, etc., but hydrogen bonds are preferred because they increase the heat resistance of the polyimide resin and also provide excellent mechanical properties. In preferred embodiment 2, the above hydrogen bond forming structure, which is particularly effective in forming hydrogen bonds, is introduced into the polyimide resin.

Among the above hydrogen bond-forming structures, -C(O)NH- (amide bond), -NHC(O)NH- (urea bond), and -OH (hydroxyl group) are particularly preferred, especially -C(O)NH- (amide bond) is preferable from the point of view that the above-mentioned introduction effect is excellent.

There is no particular limit to the content of hydrogen bond-forming structures in the polyimide molecule, but in the case of polyamic acid, when all repeating units in the polyamic acid each contain one hydrogen bond-forming structure, it is defined as 100%. , usually larger than 0%, preferably 2% or more, more preferably 5% or more, usually less than 100%, preferably 75% or less, more preferably 50% or less. Also, in the case of polyimide resins, if all repeating units contain one structure that forms a non-covalent bond as 100%, it is usually larger than 0%, preferably 2% or more, more preferably 5% or more. , usually less than 100%, preferably 75% or less, more preferably 50% or less. By introducing the amount within this range, the polyimide resin can have better mechanical properties such as tensile modulus and elongation.
Note that the content of hydrogen bond-forming structures in polyimide molecules can usually be determined by NMR, IR, Raman, titration, mass spectrometry, or the like.

Examples of methods for introducing a hydrogen bond-forming structure into the repeating units of polyimide resin include a method of polymerizing a monomer having a hydrogen bond-forming structure when producing a polyimide resin, and a method of forming a hydrogen bond-forming structure through a polymerization reaction. In particular, a method in which a monomer having one or more types of hydrogen bond-forming structures is used as a raw material for producing a polyimide resin and polymerized is preferred.

Examples of monomers having one or more hydrogen bond-forming structures (hereinafter sometimes referred to as "hydrogen bond-forming monomers") include tetracarboxylic dianhydrides and diamine compounds having one or more hydrogen bond-forming structures. .

Specifically, examples of the tetracarboxylic dianhydride include 3,3',4,4'-benzophenonetetracarboxylic dianhydride, and examples of the diamine compound include 4,4'-diamino Benzanilide, 4,4'-bis(4-aminobenzamide)-3,3'-dihydroxybiphenyl, 2,2'-bis(3-amino-4-hydroxyphenyl)sulfone, 2,2'-bis(3 Examples thereof include -amino-4-hydroxyphenyl)propane, 4,4'-diamino-3,3'-dihydroxybiphenyl, and bis(4-amino-3-carboxyphenyl)methane. These hydrogen bond-forming monomers may be used alone or in combination of two or more in any ratio.
Among these, it is particularly preferable to use 4,4'-diaminobenzanilide because of its excellent introduction effect.

The amount of these hydrogen bond forming monomers introduced is not particularly limited, but in the case of polyamic acid, it is usually 0.5 mol% or more, preferably 5 mol% or more, more preferably 10 mol% of the total repeating units of polyamic acid. The above amount is usually 50 mol% or less, preferably 40 mol% or less, more preferably 30 mol% or less. Also, in the case of polyimide resin, it is usually 0.5 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, usually 50 mol% or less, preferably 40 mol% or less, more preferably It is 30 mol% or less. By introducing the hydrogen bond-forming monomer in an amount within this range, it is easy to obtain a polyimide resin that has both high elasticity and high elongation. Hereinafter, this amount of hydrogen bond-forming monomer introduced will be referred to as "the amount of hydrogen bond-forming monomer introduced."

<Preferred aspect 3>
It is preferable that the polyimide resin of the present invention has its molecular ends sealed. By sealing the molecular ends, the formation of covalent bonds as described in the above-mentioned preferred embodiment 2 is suppressed, and flexibility is improved. By maintaining this, the bending resistance is further improved.

As a method for obtaining a polyimide resin whose molecular terminals are capped, there is a method in which a monofunctional compound is reacted as a terminal capping agent when producing a polyamic acid or a polyimide resin. Such terminal capping agents include, but are not particularly limited to, acid anhydrides, amines, epoxies, isocyanates, alcohols, and the like. Among these, acid anhydrides or amines are preferred in order to maintain reaction efficiency and heat resistance.

Examples of acid anhydrides include aromatic acid anhydrides and aliphatic acid anhydrides.
Examples of aromatic acid anhydrides include phthalic anhydride, 2,3-naphthalenedicarboxylic anhydride, 1,2-naphthalenedicarboxylic anhydride, 4-methylphthalic anhydride, 3-methylphthalic anhydride, 4- Examples include chlorophthalic anhydride, 4-tert-butylphthalic anhydride, and 4-fluorophthalic anhydride.
Aliphatic acid anhydrides have a linear structure or a cyclic structure. Examples of aliphatic acid anhydrides with a linear structure include butylsuccinic anhydride, decylsuccinic anhydride, n-octylsuccinic anhydride, and dodecylsuccinic anhydride. Examples include anhydride, (2-methyl-2-propyl)-succinic anhydride, and 2-octylsuccinic anhydride.
In addition, examples of aliphatic acid anhydrides having a cyclic structure include cis-1,2-cyclohexylcarboxylic anhydride, tras-1,2-cyclohexyldicarboxylic anhydride, and 4-methylcyclohexane-1,2-dicarboxylic anhydride. Examples include things.
In particular, in order to maintain mechanical properties and heat resistance, phthalic anhydride, 2,3-naphthalenedicarboxylic anhydride, 1,2-naphthalenedicarboxylic anhydride, 4-methylphthalic anhydride or 3-methylphthalic anhydride is used. preferable.

Examples of amines include aromatic amines and aliphatic amines.
Examples of aromatic acid amines include aniline, 1-naphthylamine, 1-aminoanthracene, 2-aminoanthracene, 9-aminoanthracene, N,N-dimethyl-1,4-phenylenediamine, 2-chloroaniline, 4-aminoanthracene, Chloroaniline, 4-aminopyridine, cytosine, p-toluidine, 4-butylaniline, 4-(2-aminoethyl)pyridine, 4-amino-4-ethylpyridine, 4-amino-3-ethylpyridine and isonicotinamide Examples include.
Aliphatic amines have a linear structure or a cyclic structure, and examples of aliphatic amines having a linear structure include ethylamine, tert-butylamine, isopropylamine, isobutylamine, neopentylamine, and propylamine.
Examples of aliphatic amines having a cyclic structure include cyclohexylamine, 4-methylcyclohexylamine, 3-methylcyclohexylamine, aminomethylcyclohexane, 4-(2-aminoethyl)cyclohexylamine, and 4-butylcyclohexylamine.
In order to maintain mechanical properties and heat resistance, phthalic anhydride, aniline, 4-aminopyridine and 1-naphthylamine are preferred.

Epoxies include phenylglycidyl ether, methylphenylglycidyl ether, dimethylphenylglycidyl ether, trimethylphenylglycidyl ether, tetramethylphenylglycidyl ether, ethylphenylglycidyl ether, diethylphenylglycidyl ether, triethylphenylglycidyl ether, tetraethylphenylglycidyl ether, isopropyl Phenylglycidyl ether, diisopropylphenylglycidyl ether, triisopropylphenylglycidyl ether, tetraisopropylphenylglycidyl ether, o-phenylphenol glycidyl ether, m-phenylphenol glycidyl ether, p-phenylphenol glycidyl ether, p-tertial butylphenyl glycidyl ether , o-tertial butylphenyl glycidyl ether, m-tertial butylphenyl glycidyl ether, chlorophenyl glycidyl ether, dichlorophenyl glycidyl ether, trichlorophenyl glycidyl ether, tetrachlorophenyl glycidyl ether, bromophenyl glycidyl ether, dibromophenyl glycidyl ether, tribromophenyl Examples include glycidyl ether and tetrabromophenyl glycidyl ether.

As the isocyanate, monofunctional isocyanate compounds such as n-butyl isocyanate, isopropylisocyanate, phenyl isocyanate, benzyl isocyanate, (meth)acryloyl isocyanate, 2-(meth)acryloyloxyethyl isocyanate, 3-(meth)acryloyloxypropylisocyanate, Examples include (meth)acryloyloxyalkylisocyanates such as 2-(meth)acryloyloxy-1-methylethyl isocyanate and 2-(meth)acryloyloxy-2-methylethylisocyanate.

Examples of alcohol include methanol; ethanol; 1-propanol and 2-propanol having 3 carbon atoms; 1-butanol, 2-butanol, isobutanol and t-butanol having 4 carbon atoms; 1-butanol having 5 carbon atoms; -Pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-ethyl-1-propanol, etc.; 1-hexanol, 2-carbon number 6; -Hexanol, 3-hexanol, 2-methyl-1-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 2-methyl-3-pentanol, 2-ethyl-1-butanol , 3-ethyl-2-butanol, 2,3-dimethyl-1-butanol, cyclohexanol, etc.; 1-heptanol, 2-heptanol, 3-heptanol, 4-heptanol, 2-methyl-1 having 7 carbon atoms -Hexanol, 2-methyl-3-hexanol, 2-methyl-4-hexanol, 3-methyl-1-hexanol, 3-methyl-2-hexanol, 3-methyl-4-hexanol, 2-ethyl-1-pene Tanol, 2-ethyl-3-pentanol, 2,2-dimethyl-1-pentanol, 2,3-dimethyl-1-pentanol, 2,4-dimethyl-1-pentanol, etc.; carbon number is 8 , 1-octanol, 2-octanol, 3-octanol, 4-octanol, 2-methyl-1-heptanol, 2-methyl-3-heptanol, 2-methyl-4-heptanol, 2-ethyl-1-hexanol, 2 -Ethyl-3-hexanol, 2-ethyl-4-hexanol, 2-propyl-1-pentanol, 2-propyl-3-pentanol, 2-propyl-4-pentanol, 2,3-dimethyl-1- Hexanol and 2,4-dimethyl-1-hexanol, etc.; 1-nonanol, 2-nonanol, 3-nonanol, 4-nonanol, 5-nonanol, 2-methyl-1-octanol, 2-methyl having 9 carbon atoms -3-octanol, 2-methyl-4-octanol, 2-methyl-5-octanol, 2-methyl-6-octanol, 2-ethyl-1-heptanol, 2-ethyl-3-heptanol, 2-ethyl-4 -heptanol, 2-ethyl-5-heptanol, 2,6-dimethyl-1-heptanol, 2,6-dimethyl-4-heptanol, 3,5,5-trimethyl-1-hexanol, 3,5,5-trimethyl -2-hexanol and 2,2,4-trimethyl-1-hexanol, etc.; 1-decanol, 2-decanol, 3-decanol, 4-decanol, 5-decanol, 2-methyl-1- having 10 carbon atoms nonanol, 2-methyl-3-nonanol, 2-methyl-4-nonanol, 2-methyl-5-nonanol, 2-ethyl-1-octanol, 2-ethyl-3-octanol, 2-ethyl-4-octanol and 2-ethyl-5-octanol, etc.; 1-dodecanol, 2-dodecanol, 3-dodecanol, 4-dodecanol, 2-methyl-1-undecanol, 2-ethyl-1-decanol and 2-propyl having 11 carbon atoms -1-nonanol, etc.; 1-dodecanol, 2-dodecanol, 3-dodecanol, 1-ethyl-1-decanol, 2-ethyl-1-decanol, 3-ethyl-1-decanol and 2- Butyl-1-octanol, etc.; 1-tridecanol, 2-tridecanol, 3-tridecanol, 1-ethyl-1-undecanol, 2-ethyl-1-undecanol, 3-ethyl-1-undecanol and 2-tridecanol, which have 13 carbon atoms; -butyl-1-nonanol, etc.; carbon 14, 1-tetradecanol, 2-tetradecanol, 3-tetradecanol, 2-methyl-1-tridecanol, 2-ethyl-1-dodecanol and 2-propyl -1-undecanol etc.; carbon 15, 1-pentadecanol, 2-pentadecanol, 3-pentadecanol, 2-methyl-1-tetradecanol, 2-ethyl-1-tridecanol, 2-propyl -1-dodecanol etc.; carbon 16, 1-hexadecanol, 2-hexadecanol, 3-hexadecanol, 2-methyl-1-pentadecanol, 2-ethyl-1-tetradecanol and 2-hexadecanol; -Propyl-1-tridecanol, etc.; carbon 17, 1-heptadecanol, 2-heptadecanol, 3-heptadecanol, 2-methyl-1-hexadecanol, 2-ethyl-1-pentadecanol and 2-propyl-1-tetradecanol, etc.; carbon 18, 1-octadecanol, 2-octadecanol, 3-octadecanol, 2-methyl-1-heptadecanol, 2-ethyl-1 -Hexadecanol and 2-propyl-1-pentadecanol, etc.; carbon 19, 1-nonadecanol, 2-nonadecanol, 3-nonadecanol, 2-methyl-1-octadecanol, 2-ethyl-1-heptadecanol Decanol and 2-propyl-1-hexadecanol, etc.; carbon 20, 1-eicosanol, 2-eicosanol, 3-eicosanol, 2-methyl-1-nonadecanol, 2-ethyl-1-octadecanol and -Propyl-1-heptadecanol and other monohydric alcohols.

The sealing rate of the molecular terminals of the polyimide resin is preferably 30% or more, more preferably 50% or more, even more preferably 80% or more, particularly preferably 90% or more, and the upper limit is 100%. In particular, the terminal sealing rate of the polyimide resin is preferably 80% or more and 100% or less.
The terminal sealing rate of polyimide resin can usually be determined by NMR, IR, Raman, titration, mass spectrometry, or the like.

The polyimide resin used in the present invention may have only the requirements of the above-mentioned preferred embodiment 1, only the requirements of preferred embodiment 2, or only the requirements of preferred embodiment 3. It may have any two of the requirements of preferred aspects 1 to 3, or it may have all of the requirements.

<Manufacturing method>
There are no particular limitations on the method for producing the polyimide resin, and conventionally known imidization methods can be used. For example, in the presence of a reaction solvent, the above-mentioned tetracarboxylic dianhydride and diamine compound are subjected to an imidization reaction using heat dehydration or a dehydrating reagent, and in the presence of a reaction solvent, the tetracarboxylic dianhydride and diamine compound are amidated Examples include a method in which a polyimide precursor (polyamic acid) obtained by reaction is obtained, and then the precursor is subjected to an imidization reaction by heating and dehydrating or using a dehydrating reagent. By allowing the above-mentioned hydrogen bond-forming monomer and the terminal capping agent to exist in the reaction system in the required amount, the polyimide resin having repeating units containing a hydrogen bond-forming structure and the molecular terminals can be blocked. polyimide resin can be produced. Furthermore, the reaction may be carried out in the presence of other monomers mentioned above in this reaction system.

Hereinafter, the tetracarboxylic dianhydride, diamine compound, hydrogen bond forming monomer, terminal capping agent, and other monomers will be collectively referred to as "raw materials for tetracarboxylic dianhydride, diamine compound, etc.".

As the dehydration reagent, conventionally known reagents can be used, and examples thereof include acid anhydrides such as acetic anhydride, propionic anhydride, benzoic anhydride, trifluoroacetic anhydride, and chloroacetic anhydride.

The method of reacting raw materials such as tetracarboxylic dianhydride and diamine compound in a solvent is not particularly limited. Furthermore, the order and method of adding raw materials such as tetracarboxylic dianhydride and diamine compound are not particularly limited. For example, polyimide or polyamic acid can be obtained by sequentially adding a tetracarboxylic dianhydride and a diamine compound to a solvent and stirring at an appropriate temperature.

The amount of the diamine compound is usually 0.7 mol or more, preferably 0.8 mol or more, and usually 1.3 mol or less, preferably 1.2 mol or less, per 1 mol of the tetracarboxylic dianhydride. be. By setting the amount of the diamine compound within such a range, polyimide or polyamic acid with a high degree of polymerization can be obtained, and film forming properties and film forming properties tend to be improved.

The concentration of raw materials such as tetracarboxylic dianhydride and diamine compound in the solvent can be appropriately set depending on the reaction conditions and the viscosity of the obtained polyimide precursor.

The total amount of raw materials such as tetracarboxylic dianhydride and diamine compounds is not particularly limited, but is usually 1% by weight or more based on the total amount of the solution containing raw materials such as tetracarboxylic dianhydride and diamine compounds and the solvent. , preferably 5% by weight or more, usually 70% by weight or less, preferably 50% by weight or less. By carrying out polymerization within this concentration range, a uniform polyimide varnish or polyamic acid varnish with a high degree of polymerization can be obtained. When polymerizing at a total concentration of less than 1% by weight of raw materials such as tetracarboxylic dianhydride and diamine compounds, the degree of polymerization of polyimide or polyamic acid will not be sufficiently high, and the final polyimide resin will become brittle. There is. On the other hand, when polymerization is carried out at a concentration higher than 70% by weight, the solution viscosity increases and stirring may become difficult.

When obtaining a polyimide resin in a solution, the temperature at which raw materials such as tetracarboxylic dianhydride and diamine compounds are reacted in a solvent is not particularly limited as long as the reaction proceeds, but is usually 20°C or higher, The temperature is preferably 40°C or higher, usually 240°C or lower, preferably 220°C or lower.
The reaction time is usually 1 hour or more, preferably 2 hours or more, and usually 100 hours or less, preferably 42 hours or less. By carrying out the process under such conditions, it is likely that a polyimide resin can be obtained at low cost and in good yield.
The pressure during the reaction may be normal pressure, increased pressure, or reduced pressure. The atmosphere may be air or an inert atmosphere, but an inert atmosphere is preferable from the viewpoint of the polyimide resin obtained and the flexability of the laminate of the present invention.

When obtaining a polyamic acid in a solution, the temperature at which raw materials such as tetracarboxylic dianhydride and diamine compounds are reacted in a solvent is not particularly limited as long as the reaction proceeds, but is usually 0°C or higher, The temperature is preferably 20°C or higher, usually 120°C or lower, preferably 100°C or lower.
The reaction time is usually 1 hour or more, preferably 2 hours or more, and usually 100 hours or less, preferably 42 hours or less. By carrying out the process under such conditions, polyamic acid tends to be obtained at low cost and in good yield.
The pressure during the reaction may be normal pressure, increased pressure, or reduced pressure. The atmosphere may be air or an inert atmosphere, but an inert atmosphere is preferable from the viewpoint of the polyimide resin obtained and the bending followability of the laminate of the present invention.

The solvent used when reacting raw materials such as tetracarboxylic dianhydride and diamine compounds is not particularly limited, but examples include hydrocarbons such as hexane, cyclohexane, heptane, benzene, naphtha, toluene, xylene, mesitylene, and anisole. Solvent: Halogenated hydrocarbon solvent such as carbon tetrachloride, methylene chloride, chloroform, 1,2-dichloroethane, chlorobenzene, dichlorobenzene, fluorobenzene; Ether solvent such as diethyl ether, tetrahydrofuran, 1,4-dioxane, methoxybenzene, etc. Ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, methyl isobutyl ketone; Glycol solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate; N,N-dimethyl Amide solvents such as formamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; Sulfonic solvents such as dimethylsulfoxide; Heterocyclic solvents such as pyridine, picoline, lutidine, quinoline, and isoquinoline; Phenol, cresol, etc. and lactone solvents such as γ-butyrolactone, γ-valerolactone, and δ-valerolactone. Among these, glycol-based solvents, amide-based solvents, and lactone-based solvents are preferable because they have high solubility in polyimide or polyamic acid and tend to have composition viscosity that is easy to handle with normal manufacturing equipment. One type of these solvents may be used alone, or two or more types may be used in any ratio and combination.

An organic amine compound may be used as a catalyst in order to increase the reactivity of raw materials such as tetracarboxylic dianhydride and a diamine compound. Examples of organic amine compounds include tertiary alkylamines such as trimethylamine, triethylamine, tripropylamine, and tributylamine; alkanolamines such as triethanolamine, N,N-dimethylethanolamine, and N,N-diethylethanolamine; Alkylene diamines such as triethylenediamine; pyridines such as pyridine; pyrrolidines such as N-methylpyrrolidine and N-ethylpyrrolidine; piperidines such as N-methylpiperidine and N-ethylpiperidine; imidazoles such as imidazole; quinoline, Examples include quinolines such as isoquinoline. One type of these may be used alone, or two or more types may be used in any ratio and combination.

The obtained polyimide or polyamic acid may be used as a varnish as it is by adding the following polymer having a heterocycle in the side chain, or it may be added to a poor solvent to precipitate in a solid state to form a polyimide or polyamic acid. (Polyimide precursor) It can also be obtained as a composition.

The poor solvent to be used is not particularly limited and can be appropriately selected depending on the type of polyimide or polyimide precursor; ether solvents such as diethyl ether or diisopropyl ether; ketone solvents such as acetone, methyl ethyl ketone, isobutyl ketone, methyl isobutyl ketone; Examples include alcoholic solvents such as methanol, ethanol, and isopropyl alcohol. Among these, alcoholic solvents such as methanol and isopropyl alcohol are preferred because they tend to yield a precipitate efficiently and have a low boiling point, making drying easy. One type of these solvents may be used alone, or two or more types may be used in any ratio and combination.

Polyimide or polyamic acid obtained by precipitation in a poor solvent can also be redissolved in a solvent and used as a polyimide varnish or polyamic acid varnish.

<Glass transition temperature (Tg)>
The polyimide resin used in the present invention has a glass transition temperature (Tg) measured by DMS (dynamic thermomechanical measurement device) of preferably 250°C or higher, more preferably 260°C or higher, and still more preferably 270°C or higher. , particularly preferably 280°C or higher. It is preferable from the viewpoint of heat resistance that the glass transition temperature is equal to or higher than the above lower limit. On the other hand, the upper limit of the glass transition temperature (Tg) is not particularly limited, but is usually 400° C. or lower, and some materials do not have Tg. Note that the glass transition temperature (Tg) by the DMS method can be measured by the following method.

<Measurement of glass transition temperature>
Using a dynamic thermomechanical measurement device (manufactured by SII Nano Technology Co., Ltd., DMS/SS6100), the storage modulus and loss modulus of the sample against vibration load were measured under the following measurement conditions, and the glass transition was determined from the loss tangent. Find the temperature (Tg). This glass transition temperature (Tg) corresponds to the glass transition temperature (Tg) of polyimide resin, and it is evaluated that the higher the Tg, the better the heat resistance.
(DMS measurement conditions)
The peak top of the loss tangent (tan δ) obtained by dividing the storage modulus (E') of the polyimide film test piece by the loss modulus (E'') is defined as the glass transition temperature.
Measurement temperature range: 50°C to 400°C (heating rate: 3°C/min)
Tensile load: 5g
Test piece shape: 10mm x 10mm

[Other ingredients]
The resin composition of the present invention used for forming the polyimide layer of the polyimide laminate of the present invention may contain surfactants, antifoaming agents, organic pigments, etc. from the viewpoint of imparting coating properties, imparting processing characteristics, imparting various functions, etc. The material may contain antioxidants, ultraviolet absorbers, stabilizers such as hindered amine light stabilizers, antistatic agents, lubricating oils, flame retardants, plasticizers, mold release agents, leveling agents, and the like. Further, other resins, inorganic fillers, or organic fillers may be contained within a range that does not impair the purpose of the present invention.

Inorganic fillers include, for example, inorganic oxides such as silica, diatomaceous earth, barium ferrite, beryllium oxide, pumice and pumice balloons; hydroxides such as aluminum hydroxide and magnesium hydroxide; calcium carbonate, magnesium carbonate, and bases. metal carbonates such as magnesium carbonate, dolomite and dawsonite; metal sulfates and sulfites such as calcium sulfate, barium sulfate, ammonium sulfate and calcium sulfite; talc, clay, mica, asbestos, glass fibers, glass balloons, glass beads, silicon Silicates such as calcium acid, montmorillonite and bentonite; Carbons such as carbon fiber, carbon black, graphite and carbon hollow spheres; Molybdenum sulfide, zinc borate, barium metaborate, calcium borate, sodium borate and boron fibers, etc. Powdered, granular, plate-like or fibrous inorganic fillers such as metals, metal compounds and alloys; Powdered, granular, fibrous or whisker-like metal fillers such as silicon carbide, silicon nitride, zirconia, aluminum nitride, Powdered, granular, fibrous, or whisker-like ceramic fillers such as titanium carbide and potassium titanate may be used.

Examples of organic fillers include shell fibers such as rice husks, carbon nanotubes, fullerenes, wood flour, cotton, jute, paper strips, cellophane strips, aromatic polyamide fibers, cellulose fibers, nylon fibers, polyester fibers, and polypropylene fibers. , thermosetting resin powder and rubber.
As the filler, a material processed into a flat plate such as a non-woven fabric may be used, or a mixture of a plurality of materials may be used.

These various fillers and additive components may be added at any stage of any process for producing the resin composition of the present invention.

Among other components, it is preferable to include a leveling agent since this tends to improve the smoothness of the polyimide film formed. Examples of the leveling agent include silicone compounds. The silicone compound is not particularly limited, but examples include polyether-modified siloxane, polyether-modified polydimethylsiloxane, polyether-modified hydroxyl-containing polydimethylsiloxane, polyether-modified polymethylalkylsiloxane, polyester-modified polydimethylsiloxane, and polyester-modified hydroxyl group-containing polydimethylsiloxane. Examples include polydimethylsiloxane containing polydimethylsiloxane, polyester-modified polymethylalkylsiloxane, aralkyl-modified polymethylalkylsiloxane, highly polymerized silicone, amino-modified silicone, amino-derivative silicone, phenyl-modified silicone, and polyether-modified silicone.

[Polymer having a heterocycle in the side chain]
The polymer having a heterocycle in the side chain used in the present invention is usually a polymer of a heterocyclic compound having a vinyl group, and may be a homopolymer (homopolymer) or a copolymer.

Examples of the heterocyclic compound having a vinyl group, which is a monomer component constituting a polymer having a heterocycle in a side chain, include vinylpyrrolidone, vinylpyridine, vinylpyrrole, vinylporphyrin, vinylindole, vinylphthalimide, vinylthiophene, and the like.

Examples of homopolymers made of these heterocyclic compounds include polyvinylpyrrolidone, polyvinylpyridine, polyvinylpyrrole, polyvinylporphyrin, polyvinylindole, polyvinylphthalimide, and polyvinylthiophene.

A polymer having a heterocyclic ring in the side chain is a copolymer of two or more types of these heterocyclic compounds having a vinyl group, or a copolymer of one or more types of heterocyclic compounds having a vinyl group and another vinyl monomer. It may be a copolymer of one type or two or more types, and examples of copolymers of a heterocyclic compound having a vinyl group and other vinyl monomers include polyvinylpyridine-polystyrene copolymer, polyvinylpyrrolidone-polyvinyl alcohol. Examples include copolymers.

Among the polymers having a heterocycle in the side chain, those in which the heterocycle is composed of a nitrogen atom and a carbon atom are particularly preferable, and polyvinylpyrrolidone, polyvinylpyridine, or vinylpyrrolidone and/or vinylpyridine are used as a copolymer component. Polyvinylpyrrolidone and polyvinylpyridine are particularly preferred. In addition, a copolymer containing vinylpyrrolidone and/or vinylpyridine as a copolymerization component has 50 structural units derived from vinylpyrrolidone and/or vinylpyridine with respect to all structural units derived from monomers constituting the copolymer. It is preferable that the content is mol % or more.

The polymer having a heterocycle in the side chain used in the present invention preferably has a molecular weight of 10,000 to 2,000,000, more preferably 20,000 to 1,800,000, and has a molecular weight of 30 ,000 to 1,500,000 is more preferred. If the molecular weight is 10,000 or less, it will be easier to coordinate between the molecules of the polyimide resin, but if the molecular weight is less than 10,000, when it is coordinated between the molecules of the polyimide resin, the force between the polyimide molecules will be weakened. Functionality may not be sufficient. In addition, the "molecular weight" here refers to a weight average molecular weight (Mw), and is a polystyrene equivalent value measured by gel permeation chromatography (GPC).

These polymers having a heterocycle in the side chain may be used alone or in combination of two or more in any ratio.

The resin composition of the present invention preferably contains 0.1 to 7 parts by weight of a polymer having a heterocycle in the side chain based on 100 parts by weight of the above-mentioned polyimide resin. If the content of the polymer having a heterocycle in the side chain is less than 0.1 part by weight based on 100 parts by weight of the polyimide resin, the interlayer adhesion and bending resistance due to the blending of the polymer having a heterocycle in the side chain may deteriorate. A sufficient improvement effect cannot be obtained, and if the amount exceeds 7 parts by weight, for example, the polymer molecules having a heterocycle in the side chain are likely to be cut by heat during enameled wire processing, resulting in a decrease in bending resistance. there is a possibility.
The content of the polymer having a heterocycle in the side chain in the resin composition of the present invention is more preferably 0.5 to 5 parts by weight based on 100 parts by weight of the polyimide resin.

The resin composition of the present invention containing a polymer having a heterocycle in the side chain in the above ratio is obtained by adding a polymer having a heterocycle in the side chain to the polyimide precursor (polyamic acid) or polyimide resin produced by the method described above. Manufactured by mixing.

Note that the concentration of the polyimide precursor (polyamic acid) or polyimide resin in the resin composition of the present invention is not particularly limited, but it depends on the productivity of the resin composition, ease of handling during subsequent use, film formability, and From the viewpoint of surface smoothness during film formation, it is usually 3% by weight or more, preferably 5% by weight or more, more preferably 7% by weight or more, usually 80% by weight or less, preferably 60% by weight or less, more preferably 50% by weight. % or less, more preferably 45% by weight or less.

The concentration of the polyimide precursor (polyamic acid) or polyimide resin in the resin composition can be appropriately confirmed using a conventionally known method. For example, it can be determined from the weight ratio before and after distilling off the solvent and other components of the composition using a method such as vacuum drying.

[Formation of polyimide layer]
The polyimide layer of the polyimide laminate of the present invention contains the above-mentioned polyimide precursor (polyamic acid) or polyimide resin, a polymer having a heterocycle in the side chain, and other components blended as necessary. It is formed by forming a film of a resin composition on a base material.

The method of forming the film is not particularly limited, but examples include a method of coating it on a substrate or the like.
Examples of the coating method include die coating, spin coating, dip coating, screen printing, spraying, casting method, method using a coater, spraying method, dipping method, calendar method, and drooling method. These methods can be selected as appropriate depending on the area to be coated and the shape of the surface to be coated.

There is also no particular restriction on the method of volatilizing the solvent contained in the film formed by coating or the like. Usually, the solvent is evaporated by heating the substrate coated with the composition. The heating method is not particularly limited, and includes, for example, hot air heating, vacuum heating, infrared heating, microwave heating, and heating by contact using a hot plate, hot roll, or the like.

As the heating temperature in the above case, a suitable temperature can be used depending on the type of solvent. The heating temperature is usually 40°C or higher, preferably 100°C or higher, more preferably 200°C or higher, particularly preferably 300°C or higher, usually 1000°C or lower, preferably 700°C or lower, even more preferably 600°C or lower, particularly preferably The temperature is 500°C or less. It is preferable that the heating temperature is 40° C. or higher because the solvent is sufficiently volatilized. Furthermore, when the heating temperature is 300° C. or higher, the imidization reaction progresses quickly, making it possible to bake for a short time. The atmosphere for heating may be air or an inert atmosphere, and there is no particular restriction. However, when the polyimide layer is required to be colorless and transparent, heating may be performed under an inert atmosphere such as nitrogen to suppress coloring. preferable.

The thickness of each polyimide layer formed in one film forming step, that is, the polyimide layer constituting the polyimide laminate of the present invention, is usually 0.1 μm or more, preferably 0.2 μm or more, and more preferably is 0.3 μm or more, particularly preferably 0.5 μm or more, and usually 100 μm or less, preferably 50 μm or less, more preferably 30 μm or less, particularly preferably 10 μm or less. It is preferable that the thickness of the polyimide layer is at least the above lower limit in order to ensure the necessary thickness as the polyimide layer and obtain the covering effect. As mentioned above, there is a limit to the thickness of the polyimide layer that can be formed in one film forming process, and the upper limit is usually less than or equal to the above upper limit.

The base material forming the polyimide layer is preferably hard and heat resistant. That is, it is preferable to use a material that does not deform under the temperature conditions required for the manufacturing process. Specifically, it is preferable that the base material is made of a material having a glass transition temperature of usually 200°C or higher, preferably 250°C or higher. Examples of such base materials include glass, ceramic, metal, and silicon wafers.

When glass is used as a base material, the glass used is not particularly limited, but includes, for example, blue plate glass (alkali glass), high silicate glass, soda lime glass, lead glass, aluminoborosilicate glass, and non-alkali glass. Examples include glass (borosilicate glass, Corning Eagle XG, etc.) and aluminosilicate glass.
When using metal as the base material, the metal used is not particularly limited, and examples thereof include gold, silver, copper, aluminum, and iron. These various alloys may also be used.

The shape of the base material is not particularly limited, and may be in the shape of a film, sheet, or plate. In this case, the base material may be flat, curved, or have steps. Further, the base material may be linear or rod-shaped.
There are no particular restrictions on the form of film formation of the polyimide laminate on these base materials, and it can be formed as appropriate depending on the shape and purpose of the base material. For example, the entire surface, one surface, both surfaces, end surfaces, etc. of the substrate may be coated, or the entire surface or a portion of the substrate may be coated.
Further, the film may be a single layer or a multilayer.

[Deposition of adjacent resin layer]
As described above, the adjacent resin layer may be a polyimide layer, or may be a layer made of a resin other than the polyimide layer.

When forming a polyimide layer as an adjacent resin layer, the resin composition of the present invention is applied and heated on the previously formed polyimide layer in the same manner as described above. It is sufficient to form layers in a laminated manner, and by repeating this process, a laminate of three or more polyimide layers can be obtained. When the polyimide layer is formed by laminating three or more layers, the polyimide layer on which the polyimide layer is formed is formed from the resin composition of the present invention containing the aforementioned polymer having a heterocycle in the side chain. It is preferable to do so. The polyimide layer serving as the outermost layer does not need to contain a polymer having a heterocycle in its side chain, but containing a polymer having a heterocycle in its side chain improves interlayer adhesion with the underlying polyimide layer. Preferable from this point of view.

When forming a resin layer other than the polyimide resin layer as the adjacent resin layer, the other resin is not particularly limited, but it is preferably one that has excellent heat resistance etc. like polyimide resin, such as polyamideimide resin, polyamide resin, etc. Examples include resin, polyetherimide resin, polyesterimide, polyetheretherketone, polyethersulfone, polyphenylene sulfite, polyester, polyolefin, fluororesin, and epoxy resin.

[Application]
In the polyimide laminate of the present invention, at least one polyimide layer and an adjacent resin layer are formed on a planar base material as described above, and the formed laminate film is not peeled off from the base material. Base material using the polyimide laminate of the present invention - Display substrate, FPC, FCCL, TAB tape, laminate busbar, optical fiber, electric wire coating, thin film solar cell substrate, organic optical semiconductor lighting, LED mounting substrate, sensor substrate as a polyimide laminate It can be used for applications such as , switch substrates, etc. Examples of the base material-polyimide laminate include a metal-polyimide laminate obtained by coating a metal base material with the polyimide laminate of the present invention.

In addition, the polyimide laminate of the present invention is produced by forming at least one polyimide layer and an adjacent resin layer on a linear base material as described above, and magnetizing the film without peeling off the formed laminate film. It can be used for the above-mentioned enamelled wires, electric wires, cables, etc. used for wires.

The polyimide laminate of the present invention can also be used as a polyimide laminate film or polyimide/other resin laminate film by peeling the laminate film formed on the base material from the base material, and this laminate film can be used as a polyimide laminate film or a polyimide/other resin laminate film. It can also be used by pasting it on.

In this case, for example, the thickness of the laminated film consisting only of polyimide layers is preferably about 0.2 to 10,000 μm after 2 to 100 film forming steps.

Note that the film made of polyimide resin forming the adjacent resin layer according to the present invention preferably has the following mechanical strength, although this varies depending on the application.
The tensile modulus of the polyimide film is not particularly limited, but from the viewpoint of abrasion resistance it is preferably 2000 MPa or more, more preferably 2500 MPa or more, even more preferably 3000 MPa or more, while from the viewpoint of bending resistance it is preferably It is 10 GPa or less, more preferably 5000 or less.
Further, the tensile elongation is not particularly limited, but from the viewpoint of bending resistance, it is preferably 20% or more, more preferably 30% or more, even more preferably 50% or more, and from the viewpoint of bending followability, it is particularly the upper limit. It is preferable to have high elongation.

Because polyimide film has both such tensile modulus and tensile elongation, it has both high elastic modulus and high elongation, making it suitable for various uses such as surface protective layers, device substrates, insulating films, and wiring films. used. In addition, if the film satisfies such tensile modulus and tensile elongation when formed into a film, it can also be used as a covering material for enameled wires, for example, to meet the recent demands for smaller motors and higher output. It satisfies the bending resistance and abrasion resistance commensurate with the standard.

There are no particular restrictions on the method of peeling the laminated film formed on the base material from the base material, but physical peeling methods and laser peeling methods are suitable in that they can be peeled off without impairing the performance of the laminated film. The method is preferred.

The physical peeling method includes, for example, a method in which the periphery of the laminate consisting of a laminate film/base material is cut off to obtain a laminate film, a method in which the periphery is sucked to obtain a laminate film, and a method in which the periphery is fixed and the laminate is separated from the supporting substrate. Examples include a method of obtaining a laminated film by moving the .

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In addition, the values of various manufacturing conditions and evaluation results in the following examples have the meaning as preferable upper or lower limits in the embodiments of the present invention, and the preferable ranges are different from the above-mentioned upper or lower limits. , it may be a range defined by the values of the following examples or a combination of values of the examples.

[Raw materials used]
The raw materials used for producing the polyimide resin compositions of Examples and Comparative Examples are as follows.
3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA): manufactured by Mitsubishi Chemical Corporation Pyromellitic dianhydride (PMDA): manufactured by Tokyo Chemical Industry Co., Ltd. 4,4'-diaminodiphenyl ether ( ODA): Wakayama Seika Kogyo Co., Ltd. 4,4'-diaminobenzanilide (DABA): Wakayama Seika Kogyo Co., Ltd. Phthalic anhydride: Tokyo Chemical Industry Co., Ltd. N,N'-dimethylacetamide (DMAc): Mitsubishi Gas Chemical Co., Ltd. Polyvinylpyrrolidone K-30 (PVP K-30): Daiichi Kogyo Seiyaku Co., Ltd.

[Synthesis of polyimide precursor]
<Synthesis example 1>
In a four-neck flask equipped with a thermocouple, a condenser, and a stirrer, 340 g (1.70 mol) of 4,4'-diaminodiphenyl ether (ODA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride were added. (BPDA) 500 g (1.70 mol), phthalic anhydride 6.04 g (0.041 mol) and N,N'-dimethylacetamide (DMAc) 3830 g were added, and the mixture was heated while stirring and heated under a nitrogen atmosphere. The reaction was carried out at 80° C. for 6 hours to obtain polyimide precursor 1 with a solid content concentration of 18% by weight.

<Synthesis example 2>
In a four-neck flask equipped with a thermocouple, a condenser, and a stirrer, 340 g (1.70 mol) of 4,4'-diaminodiphenyl ether (ODA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride were added. (BPDA) 487g (1.65mol) and N,N'-dimethylacetamide (DMAc) 3768g were added, and the mixture was heated while stirring and reacted at 80°C for 6 hours under a nitrogen atmosphere to increase the solid content concentration. 18% by weight of polyimide precursor 2 was obtained.

<Synthesis example 3>
Into a four-necked flask equipped with a thermocouple, a condenser, and a stirrer, 188 g (0.94 mol) of 4,4'-diaminodiphenyl ether (ODA) and 71.3 g (0.94 mol) of 4,4'-diaminobenzanilide (DABA) were added. 31 mol), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) 368 g (1.25 mol), phthalic anhydride 3.21 g (0.021 mol) and N,N'-dimethylacetamide ( DMAc) 2,860 g was added, and the mixture was heated while stirring, and reacted at 80° C. for 6 hours under a nitrogen atmosphere to obtain polyimide precursor 3 (DABA introduction amount: 25 mol%) with a solid content concentration of 18% by weight. .

<Synthesis example 4>
In a four-necked flask equipped with a thermocouple, a condenser, and a stirrer, 327 g (1.64 mol) of 4,4'-diaminodiphenyl ether (ODA) and 124 g (0.54 mol) of 4,4'-diaminobenzanilide (DABA) were added. , 630 g (2.14 mol) of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), and 2927 g of N,N'-dimethylacetamide (DMAc), and the mixture was heated with stirring. The mixture was heated and reacted at 80° C. for 6 hours under a nitrogen atmosphere to obtain polyimide precursor 4 (DABA introduction amount: 25 mol %) with a solid content concentration of 18% by weight.

<Synthesis example 5>
In a four-necked flask equipped with a thermocouple, a condenser, and a stirrer, 203 g (1.01 mol) of 4,4'-diaminodiphenyl ether (ODA) and 77 g (0.34 mol) of 4,4'-diaminobenzanilide (DABA) were added. , 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) 348 g (1.18 mol), pyromellitic dianhydride (PMDA) 29 g (0.13 mol), and N,N'- 2988 g of dimethylacetamide (DMAc) was added, and the mixture was heated while stirring, and reacted at 80° C. for 6 hours in a nitrogen atmosphere to produce polyimide precursor 5 with a solid content concentration of 18% by weight (DABA introduction amount: 25 mol%). I got it.

[Preparation of polyamic acid varnish]
Polyamic acid varnishes PI-1 to PI-5 (for examples) and PI-6 to PI-8 (for comparative examples) were prepared according to the formulation shown in Table 1. Note that the amount of varnish used shown in Table 1 indicates parts by weight as solid content.

[Preparation of polyimide laminate]
Polyamic acid varnishes of PI-1 to PI-8 were applied onto a copper plate using a spin coater, and the temperature was raised to 500°C for 6 minutes in air to form a polyimide layer with a thickness of 5 μm. . On the polyimide layer of the obtained polyimide/Cu laminate, a second polyimide layer was again formed in the same manner as the first layer to obtain a polyimide/polyimide/Cu laminate.

[Evaluation of interlayer adhesion]
Two parallel cuts are made at 1 cm intervals in the thickness direction of the polyimide layer of the obtained polyimide laminate, adhesive tape is pasted on the upper polyimide layer, and the adhesive tape is peeled off to ensure interlayer adhesion. Gender was evaluated.
When the adhesive tape is peeled off, the upper polyimide layer and the lower polyimide layer will peel off. Interlayer adhesion: poor (x), between the upper polyimide layer and the lower polyimide layer. Interlayer adhesion was evaluated as good (◯) if the adhesive tape did not peel off but could peel between the adhesive tape and the upper polyimide layer.

The evaluation results are shown in Table-1.

From Table 1, it can be seen that interlayer adhesion is improved by including a polymer having a heterocycle in the side chain in the polyimide layer.

Claims (12)

An insulating polyimide laminate having a polyimide layer and a resin layer adjacent to the polyimide layer, the polyimide layer containing a polymer having a heterocycle composed of a nitrogen atom and a carbon atom in a side chain. Polyimide laminate. The polymer having a heterocycle composed of a nitrogen atom and a carbon atom in the side chain is selected from the group consisting of polyvinylpyrrolidone, polyvinylpyridine, and a copolymer containing vinylpyrrolidone and/or vinylpyridine as a copolymerization component. The insulating polyimide laminate according to claim 1, comprising one or more types. The insulating polyimide laminate according to claim 1 or 2, wherein the polyimide resin contained in the polyimide layer has a glass transition temperature (Tg) of 250 to 400°C. According to any one of claims 1 to 3, the polyimide resin contained in the polyimide layer has at least one of a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2). insulating polyimide laminate.

The insulating polyimide laminate according to any one of claims 1 to 4, wherein the polyimide resin contained in the polyimide layer has a structural unit represented by the following formula (3).

(In the above formula (3), R ¹ to R ⁸ may be the same or different from each other, and include a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, or a hydroxyl group) , X is a direct bond, an oxygen atom, a sulfur atom, an alkylene group having 1 to 4 carbon atoms, a sulfonyl group, a sulfinyl group, a sulfide group, a carbonyl group, an ester group, or a secondary amino group, and n is 0 to 4. ). The polyimide resin contained in the polyimide layer has a repeating unit containing a structure represented by the following formula (5), -NH-, =NH, -C(O)NH-, -NHC(O)O-, - NHC(O)NH-, -NHC(S)NH-, -NH ₂ , -OH, -C(O)OH, -SH, -C(O)N(OH)-, -(O)S(O )-, -C(O)-, and a repeating unit containing at least one structure selected from the group consisting of -C(O)SH. Polyimide laminate.

(In the above formula (5), R ^a represents a tetracarboxylic acid residue, and R ^b represents a diamine residue.) The insulation according to claim 6, wherein the polyimide resin contained in the polyimide layer has a repeating unit including a structure represented by the formula (5) and a repeating unit including a -C(O)NH- structure. Polyimide laminate. The insulating polyimide laminate according to claim 7, wherein the -C(O)NH- structure is a structure derived from 4,4'-diaminobenzanilide. The insulating polyimide laminate according to any one of claims 1 to 8, wherein molecular terminals of the polyimide resin contained in the polyimide layer are sealed. The insulating polyimide laminate according to any one of claims 1 to 9, wherein the polyimide layer has a thickness of 0.1 to 100 μm. A metal-insulating polyimide laminate comprising a metal base material coated with the insulating polyimide laminate according to any one of claims 1 to 10. A polyimide laminate comprising a polyimide layer and a resin layer adjacent to the polyimide layer, the polyimide layer containing a polymer having a heterocycle composed of a nitrogen atom and a carbon atom in a side chain. Magnet wire made of coated metal wire.