JP2011137108A - Thermosetting composition for protective film of wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosetting composition for a protective film of a wiring board, the composition capable of giving a protective film, which is flexible, has good electric insulating reliability and adhesiveness to a flexible wiring board (that is, having good adhesiveness to a polyimide film and a tin plating layer), and to provide a protective film for a wiring board obtained by curing the above composition, and a flexible wiring board coated with the protective film. <P>SOLUTION: The thermosetting composition for a protective film of a wiring board contains, as essential components, an epoxy group-containing compound having an alkoxysilyl group in the molecule, a polyurethane having a carboxyl group and a structural unit expressed by formula (1), and a solvent (in the formula, R<SP>1</SP>represents an alkylene group having 3 to 18 carbon atoms; and n is an integer of 1 or more). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a novel thermosetting composition for a protective film of a wiring board, a protective film for a wiring board obtained by curing the thermosetting composition for the protective film, and a flexible wiring board coated with the protective film It is about. More specifically, thermosetting for a protective film of a wiring board having excellent low warpage, flexibility, long-term electrical insulation reliability and good adhesion to a flexible wiring board (ie, copper coated with polyimide or tin plating). The present invention relates to a protective film, a protective film for a wiring board obtained by curing the thermosetting composition for protective film, and a flexible wiring board partially or entirely covered with the protective film.

  Conventionally, surface protection films for flexible wiring circuits are made by punching out a die that matches the pattern of a polyimide film called a coverlay film, and then pasting it using an adhesive, or UV curing with flexibility. A type or a thermosetting type overcoat agent is applied by a screen printing method, and the latter is particularly useful in terms of workability. As these curing type overcoat agents, resin compositions mainly composed of epoxy resin, acrylic resin, or composites thereof are known. These are often mainly composed of resins that have been modified, such as the introduction of a butadiene skeleton, a siloxane skeleton, a polycarbonate diol skeleton, a long-chain aliphatic skeleton, and the like. In addition, while suppressing the deterioration of chemical resistance and electrical insulation as much as possible, the improvement of flexibility and the occurrence of warpage due to curing shrinkage have been suppressed.

  However, in recent years, flexible substrates have become lighter and thinner as electronic devices become lighter and smaller, and accordingly, the effects of flexibility and curing shrinkage of the resin composition to be overcoated are becoming more prominent. . For this reason, in the present situation, the curing type overcoat agent cannot satisfy the required performance in terms of warpage due to flexibility and curing shrinkage.

  For example, Patent Document 1 discloses a resin composition using a blocked isocyanate of polybutadiene and a polyol, but the cured product is excellent in flexibility and shrinkage but has insufficient heat resistance.

  Patent Document 2 discloses a composition comprising a polyamide-imide resin obtained by reacting a polycarbonate diol and a diisocyanate compound and obtained by reacting both ends diisocyanate polyurethane and trimellitic acid, and an amine type epoxy resin. However, there is a drawback that the long-term reliability of the electrical properties of the cured product obtained from the polyamideimide resin and the amine type epoxy resin is not sufficient.

  Patent Document 3 discloses a composition containing a carboxyl group-containing polyurethane polyimide and an epoxidized polybutadiene. When this composition is dried and the solvent is removed, the carboxyl group-containing polyurethane polyimide and the epoxidized polybutadiene are contained. It had the disadvantage that it easily caused a phase separation structure and was difficult to form a uniform film.

  Further, Patent Document 4 discloses a polyamideimide resin having an organosiloxane skeleton, but the adhesion between the cured product and the substrate is not good, and a special material such as N-methyl-2-pyrrolidone is used. It is necessary to use a new solvent, and the emulsion may be dissolved particularly during screen printing, which may cause a problem.

  Patent Document 5 discloses a composition comprising a carboxyl group-containing polyurethane having a polyol unit selected from the group consisting of polybutadiene polyol, polyisoprene polyol, hydrogenated polybutadiene polyol and hydrogenated polyisoprene polyol, and an epoxy compound. . For example, when focusing on the circuit pattern forming method used in the COF (Chip on Film) mounting method, the wiring that is currently widely used in the COF mounting method is produced by the subtractive method. . As an insulating film for wiring produced by these subtractive methods, a cured product obtained from the composition disclosed in Patent Document 5 exhibits sufficient insulating performance.

  Further, Patent Document 6 discloses a thermosetting composition having good adhesion to a tin-plated copper substrate. Regarding a cured product obtained by curing this composition, the cured product (overcoat agent for flexible circuit board) disclosed in Patent Document 6 is sufficient as an insulating film for wiring produced by a subtractive method. Insulation performance is expressed.

JP-A-11-61038 JP 2004-137370 A JP 2006-307183 A JP 2004-182792 A JP 2006-348278 A International Publication No. 2007/105713

However, with the development of the semi-additive method, the distance between wirings of the flexible wiring board is expected to be further narrowed (for example, 20 μm pitch or less).
With this further narrowing of the pitch, it is desired to develop a resin having further excellent electrical insulation reliability and good adhesion to a flexible wiring board. In order to have good adhesion to a flexible wiring board used for COF mounting method with a short distance between wirings (20 μm pitch or less), it has only good adhesion to the polyimide film that is the base material of the flexible wiring board. In addition, it is required that tin having a plating layer on the wiring surface has good adhesion.
An object of the present invention is to obtain a protective film that is flexible, has good electrical insulation reliability, and has good adhesion to a flexible wiring board (that is, good adhesion to a polyimide film and a tin plating layer). An object of the present invention is to provide a thermosetting composition for a protective film for a wiring board, a protective film for a wiring board obtained by curing the composition, and a flexible wiring board covered with the protective film.

  As a result of repeated studies to solve the above problems, the present inventors have found that when a thermosetting composition containing a polyurethane having a specific structural unit, an epoxy group-containing compound having a specific structure, and a solvent is used, the heat The cured product obtained by curing the curable composition is found to be excellent in flexibility and electrical insulation reliability and have good adhesion to a polyimide film or a tin plating layer, and the present invention is completed. It came to.

  That is, the present invention (I) includes an epoxy group-containing compound having an alkoxysilyl group in a molecule, a polyurethane having a carboxyl group and having a structural unit represented by the following formula (1), and a wiring board having essential components: This is a thermosetting composition for a protective film.

(In the formula, R ¹ represents an alkylene group having 3 to 18 carbon atoms, and n represents an integer of 1 or more.)

  This invention (II) is a protective film of a wiring board obtained by hardening | curing the thermosetting composition for protective films of the wiring board of this invention (I).

  In the present invention (III), part or all of the surface of the flexible wiring board in which the wiring is formed on the flexible substrate is covered with the protective film of the wiring board of the present invention (II). This is a flexible wiring board covered with a protective film.

  Further, the present invention is the following thermosetting composition for a protective film of a wiring board [1] to [13], a protective film of a wiring board [14], and a flexible wiring board [15]. .

[1] Thermosetting for protective film of wiring board having epoxy group-containing compound having alkoxysilyl group in molecule, polyurethane having carboxyl group and structural unit represented by following formula (1) and solvent as essential components Sex composition.

(In the formula, R ¹ represents an alkylene group having 3 to 18 carbon atoms, and n represents an integer of 1 or more.)

[2] The polyurethane having a carboxyl group and the structural unit represented by the formula (1) is a polyurethane polyimide obtained by reacting raw material components essentially including the following components (a) to (d): [1] The thermosetting composition for a protective film for a wiring board according to [1].
Component (a) Diisocyanate Component (b) (Poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms Component (c) Diol having a carboxyl group Component (d) Shown by the following formula (2) Bifunctional hydroxyl-terminated imide

Wherein R ² and R ³ each independently represents a divalent aliphatic or aromatic hydrocarbon group, and Y ¹ represents a tetravalent organic group derived from a tetracarboxylic acid or an acid anhydride group thereof. X ¹ represents a divalent organic group derived from diamine or diisocyanate, and m is an integer of 0 to 20.)

[3] A raw material component in which the polyurethane having a carboxyl group and the structural unit represented by the formula (1) has the following components (a), (b), (c) and (e) as essential components: The thermosetting composition for a protective film for a wiring board according to [1], which is a polyurethane obtained by reaction.
Component (a) Diisocyanate Component (b) (Poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms Component (c) Diol having a carboxyl group Component (e) 3 hydroxyl groups in one molecule Compounds with more than

[4] The compounds according to [1] to [3], wherein the epoxy group-containing compound having an alkoxysilyl group in the molecule is a compound having an alkoxysilyl group and two or more epoxy groups in the molecule. The thermosetting composition for protective films of the wiring board in any one.

[5] The thermosetting composition for a protective film for a wiring board according to any one of [1] to [4], further comprising an epoxy-containing compound having a tricyclodecane structure.

[6] The epoxy-containing compound having a tricyclodecane structure has a tricyclo [5.2.1.0 ^2,6 ] decane structure or a tricyclo [3.3.1.1 ^3,7 ] decane structure, and The thermosetting composition for a protective film for a wiring board according to [5], which is an epoxy-containing compound having an aromatic ring structure.

[7] An epoxy-containing compound having a tricyclo [5.2.1.0 ^2,6 ] decane structure or a tricyclo [3.3.1.1 ^3,7 ] decane structure and having an aromatic ring structure is described below. The thermosetting composition for a protective film of a wiring board according to [6], which is a compound represented by the formula (3).

(In the formula, l represents 0 or an integer of 1 or more.)

[8] The solvent according to any one of [1] to [7], wherein the solvent is a mixed solvent containing two or more kinds of solvents having boiling points of 150 ° C. or more and 250 ° C. or less under atmospheric pressure. A thermosetting composition for a protective film of a wiring board.

[9] The solvent is a mixed solvent containing at least one solvent having a boiling point of 170 ° C. or more and less than 200 ° C. and at least one solvent having a boiling point of 200 ° C. or more and 220 ° C. or less under atmospheric pressure. The thermosetting composition for a protective film for a wiring board according to any one of [1] to [7].

[10] The solvent is a mixed solvent containing at least one solvent selected from the following group A and at least one solvent selected from the following group B as essential components [1] -The thermosetting composition for protective films of the wiring board in any one of [7].
Group A: Diethylene glycol diethyl ether (boiling point 189 ° C.), diethylene glycol ethyl methyl ether (boiling point 176 ° C.), dipropylene glycol dimethyl ether (boiling point 171 ° C.), 3-methoxybutyl acetate (boiling point 171 ° C.), ethylene glycol monobutyl ether acetate (boiling point) 192 ° C)
Group B: Diethylene glycol butyl methyl ether (boiling point 212 ° C.), tripropylene glycol dimethyl ether (boiling point 215 ° C.), triethylene glycol dimethyl ether (boiling point 216 ° C.), ethylene glycol dibutyl ether (boiling point 203 ° C.), diethylene glycol monoethyl ether acetate (boiling point) 217 ° C.), γ-butyrolactone (boiling point 204 ° C.)

[11] The thermosetting composition for a protective film for a wiring board according to any one of [1] to [10], further comprising a curing accelerator.

[12] The curing accelerator may be one or more selected from the group consisting of melamine, imidazole compounds, cycloamidine compounds and derivatives thereof, phosphine compounds, and amine compounds. The thermosetting composition for protective films of the described wiring board.

[13] The thermosetting composition for a protective film of a wiring board according to any one of [1] to [12], further comprising inorganic fine particles and / or organic fine particles.

[14] A protective film for a wiring board obtained by curing the thermosetting composition for a protective film for a wiring board according to any one of [1] to [13].

[15] A flexible wiring board in which wiring is formed on a flexible substrate, wherein a part or all of the surface on which the wiring is formed is covered with the protective film of the wiring board described in [14]. A flexible wiring board covered with a protective film.

The cured product of the present invention has good handling properties, good flexibility and moisture resistance, long-term electrical insulation reliability at a high level, low warpage, and adhesion to a substrate. Good properties. For this reason, when applying the curable composition of the present invention to a flexible substrate such as a flexible wiring board or a polyimide film, and then creating a cured product (protective film) by a curing reaction, a flexible wiring board with a protective film or The warp of the flexible base material with the protective film is small, and the alignment of the IC chip mounting process is facilitated thereafter.
Moreover, since the cured product of the present invention has flexibility, it is possible to provide a flexible wiring board (for example, a flexible printed wiring board such as COF) with an electrically insulating protective film that is less susceptible to cracking.

Hereinafter, the present invention will be specifically described.
First, the present invention (I) will be described.
The invention (I) protects a wiring board comprising an epoxy group-containing compound having an alkoxysilyl group in the molecule, a polyurethane having a carboxyl group and a structural unit represented by the following formula (1), and a solvent as essential components. It is a thermosetting composition for a film.

(In the formula, R ¹ represents an alkylene group having 3 to 18 carbon atoms, and n represents an integer of 1 or more.)

First, an epoxy group-containing compound having an alkoxysilyl group in the molecule, which is one of the essential components of the composition of the present invention (I), will be described.
The epoxy group-containing compound having an alkoxysilyl group in the molecule, which is one of the essential components of the composition of the present invention (I), is not particularly limited as long as it is a compound having an alkoxysilyl group and an epoxy group in one molecule. There is no.
Examples of the epoxy group-containing compound having an alkoxysilyl group in the molecule include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycid Examples thereof include xylpropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and a compound represented by the following formula (4).

(In the formula, plural R ^{4 s} each independently represent a methyl group, a methoxy group, and an ethoxy group, and p and q each independently represent an integer of 1 or more.)

  As a commercial item of the compound represented by Formula (4), Composeran E102, E102B, E103, E103A, E201, E202 (made by Arakawa Chemical Industries Ltd.) etc. can be mentioned, for example.

  Examples of the epoxy group-containing compound having an alkoxysilyl group in the molecule include 3- (meth) acryloyloxypropyltrimethoxysilane, 3- (meth) acryloyloxypropylmethyldimethoxysilane, and 3- (meth) acryloyloxypropyl. A compound having a polymerizable unsaturated group and an alkoxysilyl group in one molecule, such as triethoxysilane, 3- (meth) acryloyloxypropylmethyldiethoxysilane, p-styryltrimethoxysilane, glycidyl (meth) acrylate, List polymer compounds obtained by copolymerizing a polymerizable compound containing a compound having a polymerizable unsaturated group and an epoxy group as essential components in one molecule such as 4- (meth) acryloyloxybutyl glycidyl ether. You can also.

The amount of the epoxy group-containing compound having an alkoxysilyl group in the molecule is the amount of the epoxy group contained in the thermosetting composition of the present invention (I) including the epoxy group-containing compound having a tricyclodecane structure described later. In the thermosetting composition of the present invention (I) comprising a total number and a polyurethane having a carboxyl group and a structural unit represented by the formula (1), which is an essential component of the present invention (I) described later It can show by ratio with the number of the carboxyl group contained.
The ratio of the total number of epoxy groups to the total number of carboxyl groups contained in the thermosetting composition of the present invention (I) is preferably in the range of 1/2 to 3/1, more preferably 1 / The range is 1.5 to 2.5 / 1. When this ratio is larger than 3/1, there is a high possibility that many unreacted epoxy groups remain, which is not preferable. On the other hand, if this ratio is less than ½, many carboxyl groups remain, which is not preferable in terms of electrical insulation performance.

In addition, the expression “(meth) acryloyl” described in the present specification means acryloyl and / or methacryloyl.
Furthermore, the expression “(meth) acrylate” as used herein means acrylate and / or methacrylate.

  Among the epoxy group-containing compounds having an alkoxysilyl group in the molecule, preferred are compounds represented by the formula (4) and compounds having a polymerizable unsaturated group and an alkoxysilyl group in one molecule. And an alkoxysilyl group in the molecule such as a polymer compound obtained by copolymerizing a polymerizable compound having a compound having a polymerizable unsaturated group and an epoxy group as essential components in one molecule and an epoxy A compound having two or more groups.

Next, a polyurethane having a carboxyl group and having a structural unit represented by the formula (1), which is one of the essential components of the composition of the present invention (I), will be described.
A polyurethane having a carboxyl group and having a structural unit represented by the formula (1), which is one of the essential components of the composition of the present invention (I), is represented by the carboxyl group and the formula (1) in the same molecule. There is no particular limitation as long as the polyurethane has a structural unit.

In the formula, R ¹ represents an alkylene group having 3 to 18 carbon atoms, and n represents an integer of 1 or more.
A preferable structure of R ¹ is an alkylene group having 6 to 14 carbon atoms, and more preferably an alkylene group having 9 to 12 carbon atoms. In the case of an alkylene group having 2 or less carbon atoms, the water resistance of the resulting polyurethane cannot be kept sufficiently, which is not preferable. Further, in the case of an alkylene group having 19 or more carbon atoms, the type of solvent capable of dissolving the generated polyurethane may be extremely reduced, or adhesion to polyimide may be lowered, which is not preferable. .
n is preferably an integer of 1 to 20.

  The structural unit of the formula (1) is a structural unit derived from a (poly) carbonate diol raw material having a diol structural unit having 3 to 18 carbon atoms. In order to further increase water resistance, a dimer diol is added to a carboxyl group. It can be used as one component when producing a polyurethane having a structural unit represented by formula (1) and is preferred. The raw material (poly) carbonate diol having a number average molecular weight of 400 to 10,000 can be used.

In addition, the expression “(poly) carbonate” in the (poly) carbonate diol described in the present specification means that the molecule has one or more carbonate bonds. In other words, “(poly) carbonate” means both monocarbonate and polycarbonate. Therefore, “(poly) carbonate diol” described in the present specification means a compound having one or more carbonate bonds in the molecule and two alcoholic hydroxyl groups.
In addition, when the (poly) carbonate diol is produced, the raw material diol component may remain and be included. In the present specification, the remaining diol component is referred to as “(poly) carbonate diol”. It is defined as not included.
For example, when (poly) carbonate diol is produced by transesterification using 1,9-nonanediol and diethyl carbonate as raw materials in the presence of a catalyst, the raw material 1,9-nonanediol is a product. When 5 mass% remains in a certain (poly) carbonate diol, it means that the remaining 1,9-nonanediol is not included in the “(poly) carbonate diol”.

  Polyurethanes having a carboxyl group and having a structural unit represented by formula (1) are generally (poly) carbonate polyols and carboxyls having an organic residue derived from a diisocyanate, a diol having 3 to 18 carbon atoms. It can be produced by reacting a diol having a group. The production of the polyurethane having a carboxyl group and the structural unit represented by the formula (1) can be carried out, for example, by a method described in JP-A-2007-39673.

In order to suppress warping during curing of the composition of the present invention (I), the increase in the crosslinking density during curing should be smaller unless the solvent resistance, long-term electrical insulation properties, and heat resistance of the cured product are impaired. desirable. A structural unit having a carboxyl group and represented by the formula (1) in order to suppress an increase in the crosslinking density during curing to some extent and to exhibit the solvent resistance, long-term electrical insulation properties and heat resistance of the cured product. It is preferable that the polyurethane having has at least one of the following two structures in the molecule.
One of them is that the polyurethane having a carboxyl group and the structural unit represented by the formula (1) further has an imide structure. That is, the polyurethane having a carboxyl group and the structural unit represented by the formula (1) is a polyurethane polyimide having a carboxyl group and the structural unit represented by the formula (1), and further having an imide bond. It is desirable.
It is desirable that the other structure has a certain branched structure in the molecule as long as it is soluble in the solvent.

First, a polyurethane polyimide having a carboxyl group, a structural unit represented by the formula (1), and further having an imide bond will be described.
Examples of the polyurethane polyimide having a carboxyl group and having a structural unit represented by the formula (1) and further having an imide bond include compounds described in JP-A-2006-307183.
A polyurethane polyimide having a carboxyl group and having a structural unit represented by the formula (1) and further having an imide bond described in JP-A No. 2006-307183 has the following components (a) and (b): It can be obtained by reacting the raw materials of component (c) and component (d).
Component (a) Diisocyanate Component (b) (Poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms Component (c) Diol having a carboxyl group Component (d) represented by the formula (2) Bifunctional hydroxyl-terminated imide

In the formula, R ² and R ³ each independently represent a divalent aliphatic or aromatic hydrocarbon group, and Y ¹ represents a tetravalent organic group derived from a tetracarboxylic acid or an acid anhydride group thereof. X ¹ represents a divalent organic group derived from diamine or diisocyanate, and m is an integer of 0 to 20.

  The diisocyanate of component (a) may be any as long as it has two isocyanate groups in one molecule. For example, an aliphatic, alicyclic or aromatic diisocyanate, preferably an aliphatic, alicyclic or aromatic diisocyanate having 2 to 30 carbon atoms excluding an isocyanate group, 4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, lysine diisocyanate, 3-isocyanate methyl-3,5 , 5-trimethylcyclohexyl isocyanate (isophorone diisocyanate), 1,3-bis (isocyanate methyl) -cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5- Lid diisocyanate, tolidine diisocyanate, can be preferably exemplified xylylene diisocyanate and the like.

As the diisocyanate, a blocked diisocyanate obtained by blocking an isocyanate group with a blocking agent can be used.
Examples of the blocking agent include alcohol, phenol, active methylene, mercaptan, acid amide, acid imide, imidazole, urea, oxime, amine, imine, bisulfite, pyridine. These may be used alone or in combination. Specific blocking agents include alcohols such as methanol, ethanol, propanol, butanol, 2-ethylhexanol, methyl cellosolve, butyl cellosolve, methyl carbitol, benzyl alcohol, cyclohexanol, etc., phenols such as phenol, cresol, ethyl Phenol, butylphenol, nonylphenol, dinonylphenol, styrenated phenol, hydroxybenzoate, etc., active methylene, dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, etc., mercaptans, butyl mercaptan, Dodecyl mercaptan, etc. As acid amides, acetanilide, acetic acid amide, ε-caprolactam, δ-valerolactam, γ-butyrolol Tam, etc., acid imide type, succinimide, maleic imide, imidazole type, imidazole, 2-methylimidazole, urea type, urea, thiourea, ethylene urea, etc., oxime type, formaldoxime, acetoald Oxime, acetooxime, methyl ethyl ketoxime, cyclohexanone oxime, etc., amine type, diphenylamine, aniline, carbazole, etc., imine type, ethyleneimine, polyethyleneimine, etc., bisulfite type, bisulfite type, pyridine type, 2 -Hydroxypyridine, 2-hydroxyquinoline and the like.

The (poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms as the component (b) has an effect of imparting flexibility to a target polyurethane polyimide.
The (poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms preferably has a number average molecular weight of 500 to 10,000, more preferably 1,000 to 5,000. When the number average molecular weight is less than 500, it is difficult to obtain suitable flexibility, and when the number average molecular weight exceeds 10,000, the heat resistance and solvent resistance may be deteriorated. The (poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms is specifically UH-CARB, UN-CARB, UD-CARB, UC-CARB, Daicel manufactured by Ube Industries, Ltd. Suitable examples include PLACEL CD-PL, PLACEL CD-H manufactured by Chemical Industry Co., Ltd., and Kuraray polyol C series manufactured by Kuraray Co., Ltd. These polycarbonate polyols are used alone or in combination of two or more.

In addition, when the (poly) carbonate polyol is produced, the polyol component as a raw material may remain and be included. In the present specification, the remaining polyol component is referred to as “(poly) carbonate polyol”. It is defined as not included.
For example, when (poly) carbonate polyol is produced by transesterification using 1,9-nonanediol and diethyl carbonate as raw materials in the presence of a catalyst, the raw material 1,9-nonanediol is a product. When 5% by mass remains in a certain (poly) carbonate polyol, the remaining 1,9-nonanediol is not included in the “(poly) carbonate polyol”, but the component (x ).

  As a raw material of this polyurethane polyimide, a (poly) carbonate polyol having an organic residue derived from one kind of diol having 3 to 18 carbon atoms may be used, or two or more kinds may be used in combination.

  The diol having a carboxyl group as the component (c) is preferably a diol compound having 1 to 30 carbon atoms, and more preferably a diol compound having 2 to 20 carbon atoms. Specific examples of the diol having a carboxyl group include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, N, N-bis (hydroxyethyl) glycine, N, N -Bis (hydroxymethyl) glycine etc. can be mentioned. Among these, 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid are particularly preferable from the viewpoint of solubility in a solvent. These diols having a carboxyl group may be used alone or in combination of two or more.

  By introducing a diol having a carboxyl group as the component (c) into the polyurethane polyimide molecule, it is possible to effectively crosslink the polyurethane polyimide, and the resulting cured insulating film has heat resistance and resistance. Solvent properties can be further increased.

  The bifunctional hydroxyl-terminated imide of the component (d) can be represented by the following formula (2).

In the formula, R ² and R ³ each independently represent a divalent aliphatic or aromatic hydrocarbon group, and Y ¹ represents a tetravalent organic group derived from a tetracarboxylic acid or an acid anhydride group thereof. X ¹ represents a divalent organic group derived from diamine or diisocyanate, and m is an integer of 0 to 20.

  This bifunctional hydroxyl-terminated imide is obtained from a tetracarboxylic acid component and an amine component composed of a diamine compound and a monoamine compound having one hydroxyl group. In addition, the said diamine compound can also be substituted with the below-mentioned diisocyanate. In formula (2), m represents an integer of 0 to 20, preferably an integer of 0 to 10, more preferably an integer of 0 to 5, and particularly preferably an integer of 1 to 5. If m exceeds 20, the bending resistance of the obtained insulating film may be deteriorated.

As the tetracarboxylic acid component that is a raw material component of the bifunctional hydroxyl-terminated imide, aromatic tetracarboxylic acids, or their acid dianhydrides and esterified products of lower alcohols, the resulting polyurethane polyimide has excellent heat resistance. Therefore, it is preferable. Specifically, 2,3,3 ′, 4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 2,2 ′, 3,3′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-diphenyl ether tetracarboxylic acid, 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic acid, 3,3 ′, 4,4′-benzophenone tetracarboxylic acid, 2,2- Bis (3,4-benzenedicarboxylic acid) hexafluoropropane, pyromellitic acid, 1,4-bis (3,4-benzenedicarboxylic acid) benzene, 2,2-bis [4- (3,4-phenoxydicarboxylic acid) ) Phenyl] propane, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 1,2,4,5-naphthalenetetracarboxylic acid, , 5,8-Naphthalenetetracarboxylic acid, aromatic tetracarboxylic acids such as 1,1-bis (2,3-dicarboxyphenyl) ethane, or their acid dianhydrides and esterified products of lower alcohols, and cyclopentane Alicyclic tetracarboxylic acids such as tetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 3-methylcyclohexane-1,2,4,5-tetracarboxylic acid, or acid dianhydrides thereof And esterified products of lower alcohols. Among these, in particular, 2,3,3 ', 4'-biphenyltetracarboxylic acid, 3,3', 4,4'-diphenyl ether tetracarboxylic acid, and 2,2 ', 3,3'-biphenyltetracarboxylic acid These acid dianhydrides and esterified products of lower alcohols are preferred because they have excellent solubility in solvents when polyurethane polyimides are used.
The tetracarboxylic acid component is preferably a tetracarboxylic dianhydride that can be easily reacted with a diamine.

  The diamine compound in the amine component used as a raw material for the bifunctional hydroxyl-terminated imide is not particularly limited, and aromatic, alicyclic and aliphatic diamines can be used. Specifically, the aromatic diamine is one benzene ring such as 1,4-diaminobenzene, 1,3-diaminobenzene, 2,4-diaminotoluene, 1,4-diamino-2,5-dihalogenobenzene. Diamines containing bis (4-aminophenyl) ether, bis (3-aminophenyl) ether, bis (4-aminophenyl) sulfone, bis (3-aminophenyl) sulfone, bis (4-aminophenyl) methane, Bis (3-aminophenyl) methane, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) sulfide, 2,2-bis (4-aminophenyl) propane, 2,2-bis (3-aminophenyl) ) Propane, 2,2-bis (4-aminophenyl) hexafluoropropane, o-dianisidine, o-tolidine, torigins Diamines containing two benzene rings such as phonic acids, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenyl) Benzene, 1,4-bis (3-aminophenyl) benzene, α, α'-bis (4-aminophenyl) -1,4-diisopropylbenzene, α, α'-bis (4-aminophenyl) -1, Diamines containing three benzene rings such as 3-diisopropylbenzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexa Fluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 4,4 '-(4-aminophenoxy) biphenyl, 9,9-bis (4-a Examples thereof include diamine compounds such as diamines containing four or more benzene rings such as minophenyl) fluorene and 5,10-bis (4-aminophenyl) anthracene. The alicyclic diamine is preferably an alicyclic diamine having 5 to 30 carbon atoms having one or more aliphatic rings in the molecule, such as isophorone diamine, norbornene diamine, 1,2-diaminocyclohexane, 1,3-diamino. Examples include cyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, and the like. The aliphatic diamine is preferably an aliphatic diamine having 2 to 30 carbon atoms, and examples thereof include hexamethylene diamine and diaminododecane.

Among the diamine compounds, a bifunctional hydroxyl-terminated imide using an alicyclic diamine has high solubility in a solvent. For this reason, even when a polyurethane polyimide resin is obtained in combination with a (poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms, the polyurethane polyimide is easily dissolved in a solvent, It is particularly suitable because of its good heat resistance.
When diisocyanate is used as a raw material for the bifunctional hydroxyl-terminated imide (that is, a raw material for forming the structural unit represented by X ¹ in the formula (2)), the reactivity of the diisocyanate and the acid anhydride is increased. In consideration, aromatic diisocyanates such as tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, and 1,5-naphthalene diisocyanate are preferable, and tolylene diisocyanate and 4,4′-diphenylmethane diisocyanate are more preferable.

  The monoamine compound having one hydroxyl group in the amine component of the bifunctional hydroxyl-terminated imide is not particularly limited as long as it is a compound having one hydroxyl group and one amino group in the molecule. Aliphatic monoamine compounds having a hydroxyl group such as propanol and aminobutanol, in particular aliphatic monoamine compounds having a hydroxyl group having 1 to 10 carbon atoms, alicyclic monoamine compounds having a hydroxyl group such as aminocyclohexanol, particularly 3 to 3 carbon atoms Fragrance having a hydroxyl group such as an alicyclic monoamine compound having 20 hydroxyl groups, aminophenol, aminocresol, 4-hydroxy-4'-aminodiphenyl ether, 4-hydroxy-4'-aminobiphenyl, aminobenzyl alcohol, aminophenethyl alcohol, etc. Group monoamination Object, in particular carbon atoms can be preferably exemplified an aromatic monoamine compound having 6-20 hydroxyl groups.

  The bifunctional hydroxyl-terminated imide comprises a tetracarboxylic acid component and an amine component composed of a diamine compound and a monoamine compound having one hydroxyl group, an acid anhydride group of the tetracarboxylic acid component (or two adjacent carboxyl groups, etc. ) And the number of equivalents of the amino group of the amine component so as to be substantially equal to each other, polymerization and imidization reaction can be performed in a solvent. Specifically, a tetracarboxylic acid component (particularly tetracarboxylic dianhydride), an amine component composed of a diamine compound and a monoamine compound having a hydroxyl group, an acid anhydride group (or an adjacent dicarboxylic acid group) and an amine component. Each component is reacted in an organic polar solvent, preferably at a reaction temperature of about 100 ° C. or less, more preferably 80 ° C. or less, in such a proportion that the amino group of the amide-acid bond is approximately equivalent. Then, the amide-acid oligomer (also referred to as an amic acid oligomer) is added with an imidizing agent at a low temperature of about 0 ° C to 140 ° C or heated at a high temperature of 140 ° C to 250 ° C. Can be obtained by a method of dehydration and imidization. In the dehydration / imidation reaction, toluene or xylene may be added and reacted while removing condensed water by azeotropy.

  Examples of the solvent used in producing the bifunctional hydroxyl-terminated imide include amides such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and N-methylcaprolactam. Solvents, dimethyl sulfoxide, hexamethylphosphamide, dimethylsulfone, tetramethylenesulfone, dimethyltetramethylenesulfone-containing solvents such as sulfur atoms, cresol, phenol, xylenol and other phenolic solvents, diethylene glycol dimethyl ether (diglyme), triethylene Glycol solvents such as glycol dimethyl ether (triglyme) and tetraglyme, lactone solvents such as γ-butyrolactone, isophorone, cyclohexanone, 3,3,5-trimethylcyclohexane Ketones solvents such Sanon, pyridine, ethylene glycol, dioxane, and other solvents such as tetramethylurea and benzene optionally toluene, aromatic hydrocarbon solvents such as xylene. These organic solvents may be used alone or in combination of two or more.

  The bifunctional hydroxyl-terminated imide produced as described above may be a mixture of a plurality of bifunctional hydroxyl-terminated imides having different m in the formula (2). In the present invention, a mixture of a plurality of bifunctional hydroxyl-terminated imide oligomers having different m may be used separately for each polyimide, but can be suitably used as it is without being separated. In addition, m (average value of m in the case of a mixture) of bifunctional hydroxyl-terminated imides can be controlled by the charging ratio (molar ratio) of the diamine compound and the monoamine compound in the amine component at the time of production.

  In addition, the bifunctional hydroxyl-terminated imide produced as described above may be used as a modified imide oligomer solution by directly or concentrating or diluting the reaction solution as it is. Alternatively, the reaction solution may be poured into a non-soluble solvent such as water and isolated as a powdered product, and the powder product may be dissolved in a solvent and used when necessary.

This polyurethane polyimide, as mentioned above,
Component (a) diisocyanate,
Component (b) (poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms,
Component (c) Obtained by reacting a diol having a carboxyl group, and a component (d) having a bifunctional hydroxyl-terminated imide represented by formula (2) as essential components, the component (b ), A polyol that does not belong to any of component (c) and component (d) (hereinafter, this component is referred to as component (x)) can be used in combination.
Examples of the component (x) include 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,9-nonanediol, 2 -Methyl-1,8-octanediol, 1,10-decamethylene glycol, 1,2-tetradecanediol, 2,4-diethyl-1,5-pentanediol, 2-butyl-2-ethylpropanediol, 1, Examples include 3-cyclohexanedimethanol, 1,3-xylylene glycol, and 1,4-xylylene glycol.

  As described above, when the (poly) carbonate polyol is produced, the polyol component as a raw material may be left and contained, but in this specification, the remaining polyol component is “(poly) It is not included in “carbonate polyol” but included in component (x).

  The composition ratio of each component of component (a), component (b), component (c), and component (d) is the total number of hydroxyl groups / isocyanate groups, and the specific component [component (b) + component The molar ratio of (c) + component (d) + component (x)] / component (a) is 0.5 to 3.0, preferably 0.8 to 2.5, especially 0.9 to 2.0. It is preferable to make the ratio. When there are too many components (a), a polymerization liquid may thicken and it is unpreferable. Furthermore, the molar ratio of [component (b) + component (c) + component (x)] / component (d) is 0.01 to 100, preferably 0.1 to 10. When there are too many [component (b) + component (c) + component (x)], it is inferior in heat resistance, and when there are too many components (d), it is inferior in a softness | flexibility.

  Moreover, the organic residue which the combination of the said component (b) and the component (c) which is a raw material component at the time of manufacturing this polyurethane polyimide is induced | guided | derived from a C3-C18 diol with a number average molecular weight of 500-10000. When the (poly) carbonate polyol (component (b)) and the component (c) having a component are combined, the component (a) and [component (b) + component (c) + component (x)] (B) + component (c) + component (x)] / component (a) has a molar ratio of 0.5 to 2.5, preferably 0.8 to 2.5, and component (b ) And component (c), the molar ratio of component (c) / component (b) is 0.1 to 10, preferably 0.1 to 5. If the value of [component (b) + component (c) + component (x)] / component (a) is too small, the content of component (d) increases and the flexibility is inferior, and [component (b) + component ( If the value of c) + component (x)] / component (a) is too large, the content of component (d) decreases and the heat resistance is inferior. Moreover, in the ratio of a component (b) and a component (c), when there are too many ratios of a component (c), the viscosity of the obtained polyurethane polyimide solution will become high too much, or the hygroscopic property of the obtained cured film will become large. It is not preferable because it may be too much. On the other hand, if the proportion of the component (c) is too small, the crosslink density is lowered, and the heat resistance of the resulting cured film tends to be lowered, which is not preferable. Component (x) is preferably used in a smaller amount than component (b) or component (c), and more preferably only the polyol component remaining during the synthesis of component (b) is used.

  The resulting polyurethane polyimide preferably contains structural units of the following formulas (5) to (7).

(In the formula, X ⁶ is a divalent group obtained by removing an isocyanate group from diisocyanate, a plurality of R ²⁰ are each independently a divalent group obtained by removing a hydroxyl group from a diol having 3 to 18 carbon atoms, and t is 1) Integer of ~ 40, u represents an integer of 1-100.)

(In the formula, X ⁶ represents a divalent group obtained by removing an isocyanate group from diisocyanate, W represents a divalent group obtained by removing a hydroxyl group from a diol having a carboxyl group, and v represents an integer of 1 to 40.)

(Wherein X ⁶ is a divalent group obtained by removing an isocyanate group from diisocyanate, a plurality of R ²¹ and R ²² are each independently a divalent aliphatic or aromatic hydrocarbon group, and Y ⁴ is a tetracarboxylic acid. A tetravalent group excluding a carboxyl group, X ⁷ represents a divalent group excluding an amino group of diamine, w is an integer of 0 to 20, and x is an integer of 1 to 100.)

  Polyurethane polyimide is obtained by copolymerizing a (poly) carbonate unit derived from a diol having 3 to 18 carbon atoms, a carboxyl group-containing diol unit, and a bifunctional hydroxyl-terminated imide unit via a urethane bond, and u, v , And x indicate the degree of polymerization and the composition ratio of these units. However, this does not restrictively indicate that the above units are block copolymerized. The (poly) carbonate unit derived from a diol having 3 to 18 carbon atoms, the carboxyl group-containing diol unit, and the bifunctional hydroxyl-terminated imide unit may be block copolymerization or random copolymerization. Moreover, although the terminal is not specified, it is an isocyanate group or a hydroxyl group by the diisocyanate compound located at the terminal or each unit.

  Furthermore, in this method for producing polyurethane polyimide, all components may be dissolved in a solvent at the same time and reacted. However, when a molecular chain in which a bifunctional hydroxyl-terminated imide unit is formed in a block form is formed, it is insoluble in the solvent. Since precipitation is likely to occur, the diisocyanate and (poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms are reacted in excess with respect to the hydroxyl group of the isocyanate group, Next, it is preferable to react with a bifunctional hydroxyl-terminated imide because the reaction can be favorably advanced while maintaining solubility.

  The production method of this polyurethane polyimide will be described in detail. The reaction between a diisocyanate compound and a (poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms or a diol having a carboxyl group is not allowed to occur. It can be carried out by dissolving in a solvent or a solvent. The reaction temperature is preferably 30 ° C to 150 ° C, more preferably 30 ° C to 120 ° C, and the reaction time is usually 1 to 10 hours. This reaction is preferably performed in a nitrogen atmosphere in order to prevent the isocyanate from being deactivated by moisture.

  A diisocyanate compound obtained by reacting a diisocyanate compound with a (poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms or a diol having a carboxyl group, and a bifunctional hydroxyl-terminated imide The reaction can be suitably carried out in a solvent, preferably at a reaction temperature of 30 ° C. to 150 ° C., more preferably 30 ° C. to 120 ° C., preferably for a reaction time of 1 to 15 hours under a nitrogen atmosphere. In this reaction, the ratio of the number of hydroxyl groups of the bifunctional hydroxyl-terminated imide to the number of isocyanate groups of the diisocyanate compound (number of hydroxyl groups / number of isocyanate groups) is 0.5 to 2.5, preferably 1.5 to 2.5. Preferably it is. If it is 0.5 or less, the heat resistance of the resulting polyurethane polyimide resin is low, and if it is 2.5 or more, it becomes too hard when it is used as a cured film.

  As the solvent that can be suitably used in the reaction for producing this polyurethane polyimide, the solvents described in the description of the solvent which is one of the essential components of the thermosetting composition of the present invention described later can be used. After synthesis, it is preferable to use a suitable solvent for the thermosetting composition of the present invention as it is. It is preferable that the usage-amount of a solvent shall be 0.8 to 5.0 times (mass ratio) of the polyurethane polyimide to produce | generate. If it is less than 0.8 times, the viscosity at the time of synthesis is too high, and the synthesis tends to be difficult due to the inability to stir. If it exceeds 5.0 times, the reaction rate tends to decrease.

  The reaction temperature is preferably 80 to 210 ° C, more preferably 100 to 190 ° C, and particularly preferably 120 to 180 ° C. If it is less than 80 ° C., the reaction time becomes too long, and if it exceeds 210 ° C., a three-dimensional reaction occurs during the reaction and gelation tends to occur. The reaction time can be appropriately selected depending on the scale of the batch and the reaction conditions employed. If necessary, the reaction may be performed in the presence of a catalyst such as a tertiary amine, an alkali metal, an alkaline earth metal, a metal such as tin, zinc, titanium, or cobalt, or a metalloid compound.

  In order to suitably obtain the thermosetting composition of the present invention, the polyurethane polyimide can be dissolved in a solvent at a high concentration of at least 3% by mass, preferably about 5 to 60% by mass. The solution viscosity at 25 ° C. (E-type rotational viscometer) is preferably 1000 to 10000000 mPa · s, particularly about 1000 to 600000 mPa · s.

  When the molecular weight of this polyurethane polyimide becomes too large, the solution viscosity becomes too high, and stirring becomes difficult during preparation of the composition. Moreover, when the composition becomes too high in viscosity, workability when forming a coating film by a method such as screen printing is lowered. Therefore, the number average molecular weight of the polyurethane polyimide constituting the resin composition of the present invention is preferably 3000 to 50000, more preferably 4000 to 40000, and particularly preferably 4000 to 30000. When the number average molecular weight is less than 3000, the heat resistance and mechanical properties of the resulting cured insulating film tend to be reduced.

  When a diol having a carboxyl group is used as the component (c) which is a raw material component of the polyurethane polyimide, the acid value of the polyurethane polyimide is preferably 5 to 120 mgKOH / g, more preferably 10 to 50 mgKOH. / G. When the acid value is less than 5 mgKOH / g, the reactivity with the epoxy group-containing compound having a tricyclodecane structure decreases, and the heat resistance of the protective film of the wiring board obtained by curing the thermosetting composition described later is reduced. May be lower. On the other hand, if it exceeds 120 mgKOH / g, the protective film may be too hard and brittle.

  The polyurethane polyimide preferably has a number average molecular weight of 3000 to 50000 and an acid value of 5 to 120 mgKOH / g, more preferably a number average molecular weight of 4000 to 30000 and an acid value of 10 ~ 50 mg KOH / g.

Next, a polyurethane having a carboxyl group, a structural unit represented by the formula (1), and having a certain branched structure in the molecule as long as it dissolves in a solvent will be described.
A polyurethane having a certain branched structure in the molecule and having a carboxyl group and a structural unit represented by the formula (1) within a range that can be dissolved in a solvent includes the following component (a), component (b), component ( It is obtained by reacting raw material components essentially comprising c) and component (e).
Component (a) Diisocyanate Component (b) (Poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms Component (c) Diol having a carboxyl group Component (e) 3 hydroxyl groups in one molecule Compounds with more than

  As a diisocyanate of a component (a), the same thing as the component (a) used for manufacture of the said polyurethane polyimide can be used.

  As the (poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms as the component (b), the same component (b) used in the production of the polyurethane polyimide can be used. However, the number average molecular weight is preferably 400 to 10000, more preferably 450 to 5000, and most preferably 500 to 3000. When the number average molecular weight is less than 400, it is difficult to obtain suitable flexibility, and when the number average molecular weight exceeds 10,000, the heat resistance and solvent resistance may be deteriorated.

As described above, when the (poly) carbonate polyol is produced, the polyol component as a raw material may be left and contained, but in this specification, the remaining polyol component is “(poly) It is defined as not included in “carbonate polyol”.
For example, when a (poly) carbonate polyol is produced by transesterification using trimethylolpropane, 1,9-nonanediol and diethyl carbonate as raw materials in the presence of a catalyst, When 5% by mass of 9-nonanediol remained in the product (poly) carbonate polyol, the remaining trimethylolpropane and 1,9-nonanediol were “(poly) When the polyol is a compound having 3 or more hydroxyl groups in one molecule (in this case, trimethylolpropane) without being included in the “carbonate carbonate polyol”, it means that the polyol belongs to the component (e). And a polyol having two hydroxyl groups in one molecule (in this case, 1, - in the case of nonanediol) is meant to be included in the components described below (y).

  As a diol which has a carboxyl group of a component (c), the same thing as the component (c) used for manufacture of the above-mentioned polyurethane polyimide can be used.

  Examples of the compound having 3 or more hydroxyl groups in one molecule of component (e) include glycerin, trimethylolethane, trimethylolpropane, tris (2-hydroxyethyl) isocyanurate, pentaerythritol, dipentaerythritol, sorbitol, and the like. Can be mentioned. Of these, trimethylolethane, trimethylolpropane, and tris (2-hydroxyethyl) isocyanurate are particularly preferable in view of ease of synthesis.

  In addition to the component (b), the component (c) and the component (e), a diol component not included in any of the component (b), the component (c) and the component (e) (hereinafter, as necessary) , Described as component (y)).

  Examples of the component (y) include 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,9-nonanediol, 2 -Methyl-1,8-octanediol, 1,10-decamethylene glycol, 1,2-tetradecanediol, 2,4-diethyl-1,5-pentanediol, 2-butyl-2-ethylpropanediol, 1, Examples include 3-cyclohexanedimethanol, 1,3-xylylene glycol, and 1,4-xylylene glycol.

As the polyurethane having a carboxyl group which is a component of the thermosetting composition of the present invention and having a structural unit represented by the formula (1), the above-mentioned component (a), component (b), component (c) and component When using the polyurethane obtained by reacting the raw material component which makes (e) essential, as a manufacturing method of this polyurethane, it can manufacture by the following method, for example.
Component (a), component (b), component (c) and component (e) are essential using a solvent in the presence or absence of a known urethanization catalyst such as dibutyltin dilaurate or dioctyltin dilaurate. It can be synthesized by reacting the raw material component (if necessary, component (y)). It is preferable to carry out this reaction without a catalyst because the physical property value of the protective film for the wiring board of the present invention (II) to be described later is improved.

  Although there is no restriction | limiting in particular about the order which prepares these raw materials, Usually, a component (b), a component (c), a component (e), and a component (y) as needed are prepared first, and it melt | dissolves in a solvent. After adding, component (a) is preferably added dropwise at 20 to 140 ° C., more preferably 60 to 120 ° C., and then preferably at 50 to 160 ° C., more preferably at 60 to 150 ° C. React.

  The starting molar ratio of the raw materials is the molecular weight and acid value of the polyurethane obtained by reacting the desired raw material components essentially comprising component (a), component (b), component (c) and component (e). Adjust accordingly. The molecular weight of the polyurethane can also be adjusted by using a monohydroxyl compound. That is, when the target number average molecular weight is reached (or when the target number average molecular weight is approached), a monohydroxyl compound is added for the purpose of blocking the terminal isocyanate group and further suppressing the increase in the number average molecular weight. .

When using a monohydroxyl compound, the number of isocyanate groups of the polyisocyanate compound may be less than or equal to the number of total hydroxyl groups of component (b), component (c), component (e) and component (y). Or there is no problem even if it is increased.
Further, when an excess of monohydroxyl compound is used, an unreacted monohydroxyl compound remains. In this case, the excess monohydroxyl compound may be used as a part of the solvent as it is. Alternatively, it may be removed by distillation or the like.
Introducing a monohydroxyl compound into a polyurethane obtained by reacting raw material components essentially comprising component (a), component (b), component (c) and component (e) increases the molecular weight of this polyurethane. In order to suppress (that is, stop the reaction), and in order to introduce the monohydroxyl compound into this polyurethane, the monohydroxyl compound is dropped into the solution at 20 to 150 ° C., more preferably at 70 to 140 ° C., Thereafter, the reaction is completed by maintaining at the same temperature.

  Moreover, it is preferable that the usage-amount of a component (e) is 0.1-5.0 mass% of all the raw material components, More preferably, it is 0.2-2.0 mass%, Most preferably, 0.3 to 1.5% by mass. If it is less than 0.1% by mass, the added effect may not be exhibited, which is not preferable. Moreover, when more than 5.0 mass%, molecular weight adjustment at the time of a synthesis | combination may become difficult, and it is unpreferable.

  As described above, the number average molecular weight of the polyurethane obtained by reacting the raw material components essentially comprising the component (a), the component (b), the component (c) and the component (e) is 1000 to 100,000. Is preferable, More preferably, it is 3000-50000, Most preferably, it is 5000-30000.

  The “number average molecular weight” described in the present specification is a number average molecular weight in terms of polystyrene measured by gel permeation chromatography (hereinafter referred to as GPC). If the number average molecular weight is less than 1,000, the elongation, flexibility, and strength of the cured film may be impaired. If the number average molecular weight exceeds 100,000, the solubility in a solvent becomes low, and the viscosity even if dissolved. Becomes higher, and there may be restrictions in terms of use.

In this specification, unless otherwise specified, the GPC measurement conditions are as follows.
Device name: HPLC unit HSS-2000 manufactured by JASCO Corporation
Column: Shodex column LF-804 (3 in series)
Mobile phase: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: JASCO Corporation RI-2031Plus
Temperature: 40.0 ° C
Sample volume: Sample loop 100 μL
Sample concentration: prepared at around 0.1% by mass.

  The acid value of this polyurethane is preferably 5 to 120 mgKOH / g, more preferably 10 to 50 mgKOH / g. When the acid value is less than 5 mgKOH / g, the reactivity with the epoxy group-containing compound having a tricyclodecane structure decreases, and the heat resistance of the protective film of the wiring board obtained by curing the thermosetting composition for protective film is low. May be lower. On the other hand, if it exceeds 120 mgKOH / g, the protective film may be too hard and brittle.

  As this polyurethane, a polyurethane having a number average molecular weight of 1000 to 100,000 and an acid value of 5 to 120 mgKOH / g and having a functional group capable of curing reaction and a carbonate bond is preferable, and more preferably, the number average molecular weight is 3000. The acid value is 10-50 mg KOH / g.

  In addition, in this specification, the acid value of polyurethane is a value of an acid value measured by a potentiometric titration method of JIS K0070.

  As the solvent that can be suitably used in the reaction for producing this polyurethane, the solvents described in the description of the solvent which is one of the essential components of the thermosetting composition of the present invention described later can be used. After synthesis, it is preferable to use a suitable solvent for the thermosetting composition of the present invention as it is. The amount of the solvent used is preferably 0.8 to 5.0 times (mass ratio) of the polyurethane to be produced. If it is less than 0.8 times, the viscosity at the time of synthesis is too high, and the synthesis tends to be difficult due to the inability to stir. If it exceeds 5.0 times, the reaction rate tends to decrease.

  As the solvent that is one of the essential components of the thermosetting composition of the present invention, a solvent having a boiling point of 150 ° C. or higher and 250 ° C. or lower under atmospheric pressure is generally used. In order to balance the solubility of the polyurethane and the volatility of the solvent, two or more solvents having a boiling point of 150 ° C. or more and 250 ° C. or less under atmospheric pressure can be used in combination. More preferably, a solvent having a boiling point of 170 ° C. or higher and lower than 200 ° C. under atmospheric pressure and a solvent having a boiling point of 200 ° C. or higher and 220 ° C. or lower under atmospheric pressure are used in combination.

  Examples of the solvent having a boiling point of 170 ° C. to 200 ° C. under atmospheric pressure include diethylene glycol diethyl ether (boiling point 189 ° C.), diethylene glycol ethyl methyl ether (boiling point 176 ° C.), dipropylene glycol dimethyl ether (boiling point 171 ° C.), 3- Examples thereof include methoxybutyl acetate (boiling point 171 ° C.), ethylene glycol monobutyl ether acetate (boiling point 192 ° C.), and the like.

  Examples of the solvent having a boiling point of 200 ° C. or higher and 220 ° C. or lower under atmospheric pressure include diethylene glycol butyl methyl ether (boiling point 212 ° C.), tripropylene glycol dimethyl ether (boiling point 215 ° C.), triethylene glycol dimethyl ether (boiling point 216 ° C.), Examples include ethylene glycol dibutyl ether (boiling point 203 ° C.), diethylene glycol monoethyl ether acetate (boiling point 217 ° C.), and γ-butyrolactone (boiling point 204 ° C.).

The combination of the following solvents is preferable in that it is highly volatile, can impart low-temperature curability, and can efficiently perform a polyurethane production reaction in a homogeneous system.
Specifically, as a solvent having a boiling point of 170 ° C. to 200 ° C. under atmospheric pressure, diethylene glycol diethyl ether (boiling point 189 ° C.), diethylene glycol ethyl methyl ether (boiling point 176 ° C.), dipropylene glycol dimethyl ether (boiling point 171 ° C.) It is preferable to combine at least one selected from the above and γ-butyrolactone (boiling point 204 ° C.) as a solvent having a boiling point of 200 ° C. or higher and 220 ° C. or lower under atmospheric pressure, and the most preferable combination is under atmospheric pressure. In combination, diethylene glycol diethyl ether (boiling point 189 ° C.) as a solvent having a boiling point of 170 ° C. to 200 ° C. and γ-butyrolactone (boiling point 204 ° C.) as a solvent having a boiling point of 200 ° C. to 220 ° C. under atmospheric pressure. It is.
Use of a combination of these preferable solvents is preferable because it has a low hygroscopic property, a high boiling point, and a low volatility, and is therefore excellent as a solvent for screen printing ink.
In order to sufficiently express the above effect, the ratio of the solvent having a boiling point of 170 ° C. to 200 ° C. under atmospheric pressure and the solvent having a boiling point of 200 ° C. or higher and 220 ° C. or lower under atmospheric pressure is expressed by mass ratio. The range is from 5:95 to 80:20, and more preferably from 10:90 to 60:40.

  Further, a solvent other than a solvent having a boiling point of 170 ° C. to 200 ° C. under atmospheric pressure and a solvent having a boiling point of 200 ° C. or higher and 220 ° C. or lower under atmospheric pressure is used in combination as long as the solubility of polyurethane is not impaired. be able to. Reactive monomers and reactive diluents can also be used as solvents.

  Content of the solvent in a thermosetting composition becomes like this. Preferably it is 25-75 mass%, More preferably, it is 35-65 mass%. If the solvent content is too low, the viscosity of the thermosetting composition becomes too high, and it tends to be difficult to print by the screen printing method, which is the most preferred printing method described later. If the solvent content is too high, the screen The spread of the thermosetting composition after printing increases, and as a result, the printing area of the actual thermosetting composition is larger than the portion (ie, the shape of the printing plate) where the thermosetting composition is to be applied. There is a tendency to become too large.

Furthermore, the thermosetting composition for a protective film of a wiring board of the present invention (I) can further contain an epoxy-containing compound having a tricyclodecane structure in order to maintain high electrical insulation reliability. Yes and preferred.
The epoxy group-containing compound having a tricyclodecane structure is not particularly limited as long as it is a compound having a tricyclodecane structure and an epoxy group in the molecule.
Examples of the tricyclodecane structure include a tricyclo [5.2.1.0 ^2,6 ] decane structure or a tricyclo [3.3.1.1 ^3,7 ] decane structure.
Examples of the epoxy group-containing compound having a tricyclo [5.2.1.0 ^2,6 ] decane structure include compounds represented by the following formula (3) and the following formula (10).

(In the formula, l represents 0 or an integer of 1 or more.)

(In the formula, g represents 0 or an integer of 1 or more.)

In addition, examples of the epoxy group-containing compound having a tricyclo [3.3.1.1 ^3,7 ] decane structure include compounds represented by the following formula (11) to the following formula (14).

Among these compounds having a tricyclo [5.2.1.0 ^2,6 ] decane structure or a tricyclo [3.3.1.1 ^3,7 ] decane structure and an epoxy group, it is preferable to reduce the water absorption rate. Specifically, an epoxy group containing a tricyclo [5.2.1.0 ^2,6 ] decane structure or a tricyclo [3.3.1.1 ^3,7 ] decane structure and having an aromatic ring structure Compounds are preferred.
Among the formulas (3) and (10) to (14), the compounds represented by the formulas (3) and (11) to (14) are applicable.

Among epoxy group-containing compounds having a tricyclo [5.2.1.0 ^2,6 ] decane structure or a tricyclo [3.3.1.1 ^3,7 ] decane structure and having an aromatic ring structure In view of the ease, the compound represented by the formula (3) is particularly preferable.
The compound represented by the formula (3) is commercially available from DIC Corporation (grade names: Epicron HP-7200L, Epicron HP-7200, Epicron HP-7200H, Epicron HP-7200HH), and also from Nippon Kayaku Co., Ltd. It is commercially available under the grade names XD-1000-2L and XD-1000 and is easily available.

The amount of the epoxy group-containing compound having a tricyclodecane structure is included in the thermosetting composition of the present invention (I) including the epoxy group-containing compound having an alkoxysilyl group in the molecule as described above. Thermosetting composition of the present invention (I) comprising a total number of epoxy groups and a polyurethane having a carboxyl group and a structural unit represented by the formula (1), which is an essential component of the present invention (I). It can show by ratio with the number of the carboxyl groups contained in a thing.
The ratio of the total number of epoxy groups to the total number of carboxyl groups contained in the thermosetting composition of the present invention (I) is preferably in the range of 1/2 to 3/1, more preferably 1 / The range is 1.5 to 2.5 / 1. When this ratio is larger than 3/1, there is a high possibility that many unreacted epoxy groups remain, which is not preferable. On the other hand, if this ratio is less than ½, many carboxyl groups remain, which is not preferable in terms of electrical insulation performance.

  The thermosetting composition of the present invention (I) can further preferably contain a curing accelerator. The curing accelerator is not particularly limited as long as it is a compound that promotes the reaction between an epoxy group and a carboxyl group. For example, melamine, acetoguanamine, benzoguanamine, 2,4-diamino-6-methacryloyloxyethyl-s -Triazines such as triazine, 2,4-methacryloyloxyethyl-s-triazine, 2,4-diamino-6-vinyl-s-triazine, 2,4-diamino-6-vinyl-s-triazine and isocyanuric acid adducts Compounds, imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl-4 -Methylimidazole, 1-cyanoethyl-2 Methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-aminoethyl-2-ethyl-4-methylimidazole, 1-aminoethyl-2-methylimidazole, 1- (cyanoethylaminoethyl) -2-methyl Imidazole, N- [2- (2-Methyl-1-imidazolyl) ethyl] urea, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-methylimidazolium trimellitate, 1-cyanoethyl-2-phenyl Imidazolium trimellitate, 1-cyanoethyl-2-ethyl-4-methylimidazolium trimellitate, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2,4-diamino-6- [2'-methyl Imidazolyl- (1 ′)]-ethyl-s-triazine 2,4-diamino-6- [2'-undecylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4'-methylimidazolyl- (1 ′)]-Ethyl-s-triazine, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, N, N′-bis (2-methyl-1-imidazolylethyl) urea, N, N′-bis ( 2-methyl-1-imidazolylethyl) adipamide, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-methylimidazole isocyanuric acid adduct, 2-phenyl Imidazole-isocyanuric acid adduct, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-tria Gin isocyanuric acid adduct, 2-methyl-4-formylimidazole, 2-ethyl-4-methyl-5-formylimidazole, 2-phenyl-4-methylformylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1- (2-hydroxyethyl) imidazole, vinylimidazole, 1-methylimidazole, 1-allylimidazole, 2-ethylimidazole, 2-butylimidazole, 2-butyl-5-hydroxymethylimidazole, Imidazoles such as 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole, 1-benzyl-2-phenylimidazole hydrobromide, 1-dodecyl-2-methyl-3-benzylimidazolium chloride Compound, 1,5-diazabicyclo 4.3.0) Nonamene-5 and salts thereof, cycloamidine compounds such as diazabicycloalkenes such as 1,8-diazabicyclo (5.4.0) undecene-7 and salts thereof, and derivatives thereof, triethylenediamine, benzyl Tertiary amino group-containing compounds such as dimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol, triphenylphosphine, diphenyl (p-tolyl) phosphine, tris (alkylphenyl) phosphine, tris (alkoxyphenyl) ) Phosphine, tris (alkylalkoxyphenyl) phosphine, tris (dialkylphenyl) phosphine, tris (trialkylphenyl) phosphine, tris (tetraalkylphenyl) phosphine, tris (dialkoxy) Eniru) phosphine, tris (tri-alkoxyphenyl) phosphine, tris (tetra-alkoxyphenyl) phosphine, trialkyl phosphine, dialkyl aryl phosphines, organic phosphine compounds such as an alkyl diaryl phosphines, can be given Jishianjiajido like.

These curing accelerators may be used alone or in combination of two or more.
Among these curing accelerators, in view of achieving both curing acceleration action and electrical insulation performance, preferable ones are melamine, imidazole compound, cycloamidine compound and derivatives thereof, phosphine compound and amine compound. More preferred are melamine, 1,5-diazabicyclo (4.3.0) nonene-5 and salts thereof, and 1,8-diazabicyclo (5.4.0) undecene-7 and salts thereof.

  There is no restriction | limiting in particular if the compounding quantity of these hardening accelerators can achieve the hardening acceleration effect. However, from the viewpoints of curability of the thermosetting composition of the present invention (I) and electrical insulating properties and water resistance of the protective film obtained by curing the thermosetting composition of the present invention (I), the present invention For 100 parts by mass of the total amount of the polyurethane having a carboxyl group and the structural unit represented by the formula (1) and the epoxy group-containing compound having a tricyclodecane structure contained in the thermosetting composition of (I) It is preferable to mix | blend in the range of 0.05-5 mass parts, More preferably, it is 0.1-3.0 mass parts. When the blending amount is less than 0.05 parts by mass, it is difficult to cure in a short time, and when it exceeds 5 parts by mass, the electrical insulation characteristics and water resistance of the cured product obtained by curing the composition are deteriorated. There is.

In the thermosetting composition of the present invention (I), inorganic fine particles and / or organic fine particles can be blended and preferably blended for the purpose of adjusting fluidity.
In the present specification, “inorganic fine particles and / or organic fine particles” means not only inorganic fine particles and organic fine particles, but also a powdery inorganic compound that is physically coated with an organic compound or chemically surfaced with an organic compound. It is defined to include organic / inorganic composite-based fine particles that have been treated.

  Inorganic fine particles and / or organic fine particles that may be used for the purpose of blending in the thermosetting composition of the present invention (I) contain an epoxy group having a tricyclodecane structure, which is an essential component of the present invention (I). There is no particular limitation as long as it forms a paste by dispersing in a composition containing a compound, a polyurethane having a carboxyl group and a structural unit represented by formula (1) and a solvent.

Examples of the inorganic fine particles include silica (SiO ₂ ), alumina (Al ₂ O ₃ ), titania (TiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), zirconia (ZrO ₂ ), and silicon nitride (Si ₃ N ₄ ). , Barium titanate (BaO · TiO ₂ ), barium carbonate (BaCO ₃ ), lead titanate (PbO · TiO ₂ ), lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), gallium oxide ( Ga ₂ O _3), spinel _{(MgO · Al 2 O 3)} , mullite _{(3Al 2 O 3 · 2SiO 2} ), cordierite _{(2MgO · 2Al 2 O 3 ·} 5SiO 2), talc (3MgO · 4SiO ₂ · H ₂ O), aluminum titanate _{(TiO 2 -Al 2 O 3)} , yttria-containing zirconia _{(Y 2} O 3 -ZrO ₂₎ Barium silicate (BaO · 8SiO _2), boron nitride (BN), calcium carbonate (CaCO _3), calcium sulfate (CaSO _4), zinc oxide (ZnO), magnesium titanate (MgO · _TiO 2), barium sulfate (BaSO ₄ ), Organic bentonite, carbon (C) and the like, and these can be used alone or in combination of two or more.

  The organic fine particles are preferably heat-resistant resin fine particles having an amide bond, an imide bond, an ester bond or an ether bond. The resin is preferably a polyimide resin or a precursor thereof, a polyamideimide resin or a precursor thereof, or a polyamide resin from the viewpoint of heat resistance and mechanical properties.

The average particle diameter of these inorganic fine particles and / or organic fine particles is preferably 0.01 to 10 μm, more preferably 0.1 to 5 μm.
The compounding amount of the inorganic fine particles and / or the organic fine particles is a polymer compound containing a polyurethane having a carboxyl group and having a structural unit represented by the formula (1), a solvent, Preferably, the amount of the epoxy group-containing compound including the epoxy group-containing compound having an alkoxysilyl group in the molecule and the epoxy-containing compound having a tricyclodecane structure is preferably 1 to 150 parts by mass, more preferably 1 It is -120 mass parts, More preferably, it is 1-60 mass parts.

The thermosetting composition for a protective film of a wiring board of the present invention (I) is, for example, a heat for a protective film of a wiring board for Chip On Film (hereinafter referred to as COF) patterned by a screen printing method. It can be used as a curable composition.
Note that “COF” described in this specification means a mounting method in which a bare chip is mounted on a flexible wiring board and connected.

When the thermosetting composition of the present invention (I) is used as a thermosetting composition for a protective film of a wiring board for COF patterned using a screen printing method, generation of bubbles during printing An antifoaming agent can and is preferably used for the purpose of extinguishing or suppressing.
The antifoaming agent is not particularly limited as long as it literally has an action of eliminating or suppressing bubbles generated when the thermosetting composition of the present invention (I) is printed.
Specific examples of the antifoaming agent used in the thermosetting composition of the present invention (I) include, for example, BYK-077 (manufactured by Big Chemie Japan), SN deformer 470 (manufactured by San Nopco), TSA750S ( Momentive Performance Materials Japan G.K.), Silicone Antifoaming Agents such as Silicone Oil SH-203 (Toray Dow Corning), Dappo SN-348 (San Nopco), Dappo SN-354 (San Nopco Co., Ltd.), Dappo SN-368 (San Nopco Co., Ltd.), Disparon 230HF (Enomoto Kasei Co., Ltd.) and other acrylic polymer antifoaming agents, Surfynol DF-110D (Nisshin Chemical Co., Ltd.) , Such as Surfinol DF-37 (manufactured by Nissin Chemical Industry Co., Ltd.) Njioru defoaming agent, and the like fluorine-containing silicone-based defoaming agent such as FA-630.

  Furthermore, the thermosetting composition of the present invention (I) includes surfactants such as a leveling agent, phthalocyanine blue, phthalocyanine green, iodin green, disazo yellow, kustal violet, carbon as necessary. Known colorants such as black and naphthalene black can be added.

  In addition, when it is necessary to suppress acid value deterioration and discoloration during heating, it is possible to add antioxidants such as phenolic antioxidants, phosphite antioxidants, and thioether antioxidants. And preferably added. Of these, phenolic antioxidants are particularly preferred. Specifically, compounds such as the following formulas (15) to (25) can be given.

  Moreover, a flame retardant and a lubricant can also be added to the thermosetting composition of this invention (I) as needed.

  The thermosetting composition of the present invention (I) can be obtained by uniformly kneading and mixing part or all of the blending components with a roll mill, a bead mill or the like. When a part of the blending components is mixed, the remaining components can be mixed when actually used.

Furthermore, when the thermosetting composition of the present invention (I) is used as a thermosetting composition for a protective film of a wiring board for COF patterned by a screen printing method, the heat of the present invention (I) In order to improve the printability of the curable composition, it is desirable to have a certain range of thixotropy index.
The “thixotropic index” described in this specification is a rotation at 25 ° C. measured using a cone / plate viscometer (manufactured by Brookfield, model: DV-II + Pro, spindle model number: CPE-52). It is defined as the ratio of the viscosity at several rpm and the viscosity at 10 rpm at 25 ° C.
When the thermosetting composition of the present invention (I) is used as a thermosetting composition for a protective film patterned by a screen printing method, the printability of the thermosetting composition of the present invention (I) is good. Therefore, the thixotropy index at 25 ° C. of the composition is preferably in the range of 1.1 to 3.0, more preferably in the range of 1.1 to 2.5. When using the thermosetting composition of the present invention (I) as a solder resist ink composition, when the thixotropy index at 25 ° C. of the curable composition is less than 1.1, after printing the curable composition, The composition may flow and may not have a constant film thickness or may not maintain a printed pattern. Moreover, when the thixotropy index at 25 ° C. of the curable composition is larger than 3.0, the defoaming property of the coating film of the printed composition may be deteriorated.

Next, the protective film of the wiring board of the present invention (II) will be described.
The present invention (II) is a protective film for a wiring board obtained by curing the thermosetting composition for a protective film for a wiring board according to the present invention (I).

The protective film of the wiring board of the present invention (II) removes part or all of the solvent in the thermosetting composition for the protective film of the wiring board of the present invention (I), and then proceeds with the curing reaction by heating. In general, a cured product is obtained. For example, when obtaining the protective film of the wiring board of the present invention (II), the protective film can be obtained through the following first to third steps.
1st process The process of printing the thermosetting composition of this invention (I), and obtaining a coating film.
2nd process The process of obtaining the coating film from which the solvent was evaporated preferably in the atmosphere of 20 to 100 degreeC, and the solvent of one part or all quantity was removed from the coating film obtained at the 1st process.
3rd process The process of obtaining the heat-cured coating film (namely, cured coating film) by heat-curing the coating film obtained at the 2nd process, preferably in 100 degreeC-250 degreeC atmosphere.

  The first step is a step of printing the thermosetting composition of the present invention (I) to obtain a coating film, but there is no particular limitation on the printing method of the thermosetting composition of the present invention (I), for example, A coating film can be obtained by coating by a screen printing method, a roll coater method, a spray method, a curtain coater method or the like, and most preferably a screen printing method.

  The second step is a step of obtaining a coating film from which part or all of the solvent has been removed by evaporating the solvent of the coating film obtained in the first step, preferably in an atmosphere of 20 ° C. to 100 ° C. The time for removing the solvent is preferably 4 hours or less, more preferably 2 hours or less.

  In the third step, the coating film obtained in the second step is preferably thermally cured in an atmosphere of 100 ° C. to 250 ° C. to obtain a thermally cured coating film (that is, a cured coating film). It is. The time for thermosetting is preferably in the range of 20 minutes to 4 hours, more preferably in the range of 30 minutes to 2 hours.

Finally, the flexible wiring board of the present invention (III) and the manufacturing method thereof will be described.
In the present invention (III), a part or all of the surface of the flexible wiring board in which the wiring is formed on the flexible substrate is covered with the protective film for the wiring board described in the present invention (II). This is a flexible wiring board covered with a protective film.
The flexible wiring board of the present invention (III) is printed on the wiring pattern portion of the flexible wiring board that has been subjected to tin plating treatment by printing the thermosetting composition for the protective film of the wiring board of the present invention (I) on the pattern. It can be manufactured by forming a printed film and forming the protective film by heating and curing the printed film preferably at 80 to 130 ° C.
The thermosetting composition of the present invention (I) can be used as a protective film for a COF wiring board, for example, by covering the entire or part of the wiring of a COF flexible wiring board.

Below, the specific process of the manufacturing method of the flexible wiring board of this invention (III) is described. For example, the protective film of a flexible wiring board can be formed through the following steps A to C.
Process A
The process of screen-printing the thermosetting composition of this invention (I) on the wiring pattern part by which the tin plating process of the flexible wiring board was carried out previously, and obtaining a coating film.
Process B
A step of obtaining a coating film from which part or all of the solvent has been removed by evaporating the solvent of the coating film obtained in step A, preferably in an atmosphere of 20 to 100 ° C.
Process C
The process of obtaining the protective film of the flexible wiring board by thermosetting the coating film obtained at the process B, Preferably it is 80-130 degreeC atmosphere.

  The temperature for evaporating the solvent in Step B is preferably 20 to 100 ° C., more preferably 60 to 100 ° C., in consideration of the evaporation rate of the solvent and quick transition to the next step (Step C). More preferably, it is 70-90 degreeC. Although there is no restriction | limiting in particular in the time to evaporate the solvent of process B, Preferably, it is 10 to 120 minutes, More preferably, it is 20 to 100 minutes. The operation of the step B is an operation performed as necessary. The operation of the step C may be performed immediately after the operation of the step A, and the curing reaction and the removal of the solvent may be performed together.

  The conditions for thermosetting performed in the step C are preferably in the range of 80 to 130 ° C. from the viewpoint of preventing the diffusion of the plating layer and obtaining warpage and flexibility suitable as a protective film. More preferably, it is 90-130 degreeC, More preferably, it is 110-130 degreeC. Although the time of the thermosetting performed at the process C does not have a restriction | limiting in particular, Preferably it is 20 to 150 minutes, More preferably, it is 30 to 120 minutes.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples.

<Measurement of acid value>
The acid value of the polyurethane having a carboxyl group and having a structural unit represented by the formula (1), which is an essential component of the present invention (I), was measured by the following method.
The solvent in the polyurethane solution having the carboxyl group and having the structural unit represented by the formula (1) was distilled off under reduced pressure to obtain a polyurethane having a carboxyl group.
Using this polyurethane having a carboxyl group, the acid value was measured according to the potentiometric titration method of JIS K0070.
The apparatus used in the potentiometric titration method is described below.
Device name: Kyoto Denshi Kogyo Co., Ltd. Automatic potentiometric titrator AT-510
Electrode: Composite glass electrode C-173 manufactured by Kyoto Electronics Industry Co., Ltd.

<Measurement of hydroxyl value>
The hydroxyl value was measured according to the neutralization titration method of JIS K0070.

<Measurement of number average molecular weight of polyurethane>
It is a value in terms of polystyrene measured by GPC, and GPC measurement conditions are as follows.
Device name: HPLC unit HSS-2000 manufactured by JASCO Corporation
Column: Three Shodex columns LF-804 connected (in series)
Mobile phase: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI-2031Plus manufactured by JASCO Corporation
Temperature: 40.0 ° C
Sample volume: Sample loop 100 μL
Sample concentration: adjusted to around 0.1% by mass

<Measurement of viscosity of polyurethane solution>
The viscosity of the carboxyl group-containing polyurethane solution was measured by the following method.
Using about 0.8 g of carboxyl group-containing polyurethane solution, rotating at a temperature of 25.0 ° C. using a cone / plate viscometer (Brookfield, model: DV-II + Pro, spindle model: CPE-52) The viscosity after 7 minutes from the start of measurement under the condition of several 5 rpm was measured.

<Measurement of thixotropy index>
The thixotropy index of the curable composition was measured by the following method.
About 0.6 g of the curable composition was used, and a thixotropy index was measured at a temperature of 25.0 ° C. using a cone / plate viscometer (manufactured by Brookfield, model: DV-II + Pro, spindle model number: CPE-52). The viscosity after the elapse of 7 minutes from the start of measurement under the condition of a rotation speed of 10 rpm was measured. Thereafter, the viscosity was measured after 7 minutes from the start of measurement under the conditions of a temperature of 25.0 ° C. and a rotation speed of 1 rpm.
The thixotropy index was calculated by the following method.
How to find the thixotropy index:
Thixotropic index = [viscosity at 1 rpm] ÷ [viscosity at 10 rpm]

<Synthesis of bifunctional hydroxyl-terminated imide>
(Reference Synthesis Example 1) Production of bifunctional hydroxyl-terminated imide (A) In a 500 mL glass separable flask equipped with a nitrogen introduction tube, a Dean-Stark receiver, and a cooling tube, 2, 3, 3 ', 4'- Charge 58.8 g (0.20 mol) of biphenyltetracarboxylic dianhydride, 17.0 g (0.10 mol) of isophoronediamine, 15.0 g (0.20 mol) of 3-aminopropanol, and 200 mL of dimethylacetamide under a nitrogen atmosphere. , And stirred at 100 ° C. for 1 hour. Subsequently, 50 mL of toluene was added and heated at 180 ° C. for 4 hours, and water generated by the imidization reaction was removed azeotropically with toluene. The reaction solution was poured into 2 L of water, and the resulting precipitate was collected by filtration, washed with water and dried under reduced pressure to obtain 78.8 g of powder. From the result of ¹ H-NMR of this compound, this compound is a bifunctional hydroxyl-terminated imide whose m (average value) in formula (2) is 1 (hereinafter referred to as bifunctional hydroxyl-terminated imide (A)). It was confirmed that.

<Synthesis of polyurethane polyimide>
(Execution synthesis example 1)
Synthesis of Polyurethane Polyimide (1) To a glass flask having a volume of 2 L equipped with a nitrogen introduction tube, Kuraray polyol C-2015 (manufactured by Kuraray Co., Ltd., (poly) carbonate diol and raw material diol (ie, 1,6-hexanediol and 3-Methyl-1,5-pentanediol), feed molar ratio of raw material diol; 1,6-hexanediol: 3-methyl-1,5-pentanediol = 85: 15, hydroxyl value 56.1 mgKOH / g , 1,6-Pexanediol residual concentration 1.5% by mass, 3-methyl-1,5-pentanediol residual concentration 0.5% by mass) 500.0 g (250 mmol), 2,2-dimethylolpropion 33.5 g (250 mmol) of acid, 156.4 g (625 mmol) of 4,4′-diphenylmethane diisocyanate ) And 697.6 g of γ-butyrolactone were charged and stirred at 60 ° C. for 3.5 hours in a nitrogen atmosphere. Next, 209.2 g (250 mmol) of the bifunctional hydroxyl-terminated imide (A) prepared in Reference Synthesis Example 1 and 20.92 g of γ-butyrolactone were added and stirred at 80 ° C. for 10 hours. The number average molecular weight determined from GPC of a solution containing this polyurethane polyimide (hereinafter referred to as polyurethane polyimide (1)) was 6800. 237.5 g of a mixed solvent of γ-butyrolactone: diethylene glycol diethyl ether = 27.7: 72.3 (mass ratio) was added to the solution containing the polyurethane polyimide (1) to adjust the solid content concentration to 44 mass%. The viscosity of this solution was 40 Pa · s. Moreover, the acid value of the polyurethane polyimide (1) was 15.6 mg-KOH / g.

<Synthesis of branched polyurethane having carboxyl group and carbonate bond>
(Execution synthesis example 2)
Synthesis of polyurethane (1) In a reaction vessel equipped with a stirrer, a thermometer and a condenser, C-1015N (manufactured by Kuraray Co., Ltd., (poly) carbonate diol and raw diol (ie, 1,9-nonanediol and 2-methyl) -1,8-octanediol), feed molar ratio of raw material diol; 1,9-nonanediol: 2-methyl-1,8-octanediol = 15: 85, hydroxyl value 112.3 mgKOH / g, 1, Residual concentration of 9-nonanediol 2.1 mass%, residual concentration of 2-methyl-1,8-octanediol 9.3 mass%) 220.4 g (0.221 mol), 2,2-dimethylolbutanoic acid ( 42.2 g (0.285 mol), trimethylolpropane 2.7 g (20.1 mmol), γ-butyrolactone Were charged 10.0g of diethylene glycol diethyl ether 90.0 g, it was dissolved. The materials were heated to 100 ° C.. The temperature of the reaction solution was lowered to 90 ° C., and 133.7 g (0.510 mol) of methylenebis (4-cyclohexylisocyanate) was added dropwise over 30 minutes with a dropping funnel. After reacting at 120 ° C. for 9 hours and confirming that the isocyanate almost disappeared, 1.3 g (28.2 mmol) of ethanol was added dropwise, and further reacted at 80 ° C. for 3 hours to have a carboxyl group and a carbonate bond. A solution containing polyurethane (hereinafter referred to as polyurethane (1)) was obtained.
The viscosity of the solution containing the obtained polyurethane (1) was 101 Pa · s. The number average molecular weight of the polyurethane (1) contained in the solution containing the polyurethane (1) was 14,000, and the acid value of the polyurethane (1) was 40.0 mg-KOH / g.
Moreover, the solid content concentration in the solution containing this polyurethane (1) was 40.0% by mass.

<Synthesis of linear polyurethane having carboxyl group and carbonate bond>
(Execution synthesis example 3)
In a reaction vessel equipped with a stirrer, a thermometer and a condenser, C-1015N (manufactured by Kuraray Co., Ltd., (poly) carbonate diol) and raw material diol (ie, 1,9-nonanediol and 2-methyl-1,8- Mixture of octanediol), feed molar ratio of raw material diol; 1,9-nonanediol: 2-methyl-1,8-octanediol = 15: 85, hydroxyl value 112.3 mgKOH / g, 1,9-nonanediol Residual concentration 7.5 mass%, 2-methyl-1,8-octanediol residual concentration 4.4 mass%) 252.8 g, 2,2-dimethylolbutanoic acid (Nippon Kasei Co., Ltd.) as a diol having a carboxyl group 47.5 g, γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) 467.5 g and diethylene glycol diethyl ether as a solvent Tell charged (made in Japan emulsifier Co., Ltd.) 82.5g, to dissolve all of the material was heated to 100 ℃. The temperature of the reaction solution is lowered to 90 ° C., and 145.6 g of methylenebis (4-cyclohexylisocyanate) (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur-W) is added as a polyisocyanate compound by a dropping funnel over 30 minutes. It was dripped. After reacting at 120 ° C. for 8 hours and confirming that the isocyanate almost disappeared, 4.0 g of isobutanol (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise, and further reacted at 80 ° C. for 3 hours to obtain a carboxyl group. And a solution containing a polyurethane solution having a carbonate bond (hereinafter referred to as polyurethane (2)).
The viscosity of the solution containing the obtained polyurethane (2) was 93 Pa · s. The number average molecular weight of the polyurethane (2) contained in the solution containing the polyurethane (2) was 13,000, and the acid value of the polyurethane (1) was 40.0 mg-KOH / g.
Moreover, the solid content concentration in the solution containing this polyurethane (1) was 45.0% by mass.

(Example formulation 1)
1,8-diazabicyclo (4.5.0) undecene-7 (hereinafter referred to as DBU) as a curing accelerator with respect to 100 parts by mass of polyurethane polyimide (1) in a solution containing polyurethane polyimide (1) ( 1 part by mass of San Apro Co., Ltd.) was added and stirred and mixed uniformly. Furthermore, 7 parts by mass of silica powder (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil R972) and 5 parts by mass of talc (manufactured by Nippon Talc Co., Ltd., trade name: SG2000) are added, first roughly kneaded, and then a three-roll mill (stock) Using Inoue Seisakusho, model: S-43 / 4 × 11), the composition containing polyurethane polyimide (1) uniformly mixed by repeating this kneading three times and performing the main kneading (hereinafter referred to as the main agent composition) (Denoted as A1).
In addition, in a container equipped with a stirrer, a thermometer and a condenser, an epoxy resin having a structure of the following formula (3) (DIC Corporation, grade name: HP-7200H, epoxy equivalent 274 g / eq) 900 g, γ-butyrolactone 540 g and 360 g of diethylene glycol diethyl ether were added and stirring was started. While continuing stirring, the temperature in the container was raised to 70 ° C. using an oil bath. After the internal temperature was raised to 70 ° C., stirring was continued for 30 minutes. Then, it confirmed that HP-7200H melt | dissolved completely, it cooled to room temperature, and the HP-7200H containing solution (henceforth hardening agent solution B1) with a density | concentration of 50 mass% was acquired.

(In the formula, l represents 0 or an integer of 1 or more.)

  216 parts by mass of main agent composition A1 and 15.2 parts by mass of curing agent solution B1, 1.0 part by mass of antifoaming agent (product name: TSA750S, manufactured by Momentive Performance Materials Japan GK) and the following formula ( 26) Silica hybrid / epoxy group-containing compound having a structure represented by 26) (produced by Arakawa Chemical Industries, Ltd., trade name: Composcelan E102B, dipropylene glycol dimethyl ether solution having a solid concentration of 50% by mass) is mixed with 15.2 parts by mass. Then, the mixture was sufficiently stirred and mixed using a spatula. Thereafter, a viscosity adjustment is performed by adding a mixed solvent of γ-butyrolactone: diethylene glycol diethyl ether = 85: 15 (mass ratio) necessary for adjusting the thixotropy index to 1.3. , Written as thermosetting composition G1).

(In the formula, p and q each independently represent an integer of 1 or more.)

(Example of formulation 2)
After stirring 227.5 parts by weight of a mixed solvent of γ-butyrolactone: diethylene glycol diethyl ether = 70: 30 (mass ratio) as a solvent and 247.5 parts by weight of the solution containing polyurethane (1) obtained in Example Synthesis Example 2, Melamine 1.1 parts by mass as thermosetting catalyst, barium sulfate (mass average particle diameter 0.5 μm) 27.5 parts by mass and Aerosil # 380 (trade name of silica fine particles manufactured by Nippon Aerosil Co., Ltd. (Diameter 12 nm) 8.25 parts by mass and 1.65 parts by mass of “Floren AC300HF” (manufactured by Kyoeisha Chemical Co., Ltd.) as an antifoaming agent are roughly kneaded, and then the main kneading is repeated three times using a three-roll mill. And a composition containing the uniformly mixed polyurethane (1) (hereinafter referred to as main agent composition A2) was obtained.
In 280 parts by mass of the main agent composition A2, 35.14 parts by mass of the curing agent solution B1 and a silica hybrid / epoxy group-containing compound having a structure represented by the formula (26) : Composeran E102B, dipropylene glycol dimethyl ether solution having a solid content concentration of 50% by mass) was added 17.57 parts by mass, followed by stirring with a resin mixer, and further γ-butyrolactone: diethylene glycol diethyl ether = 70: 30 (mass ratio) The viscosity was adjusted with a mixed solvent of diethylene glycol diethyl ether to obtain a thermosetting composition (hereinafter referred to as a thermosetting composition G2).

(Example formulation 3)
As a solvent, 22 parts by mass of a mixed solvent of γ-butyrolactone: diethylene glycol diethyl ether = 70: 30 (mass ratio) and 220 parts by mass of a solution containing the polyurethane (1) obtained in Example Synthesis Example 2 were stirred and then thermoset. Melamine 1.1 parts by weight as a catalyst, barium sulfate (mass average particle diameter 0.5 μm) 27.5 parts by weight and Aerosil # 380 (trade name of silica fine particles manufactured by Nippon Aerosil Co., Ltd., mass average particle diameter 12 nm ) 8.25 parts by mass, 1.65 parts by mass of “Floren AC300HF” (manufactured by Kyoeisha Chemical Co., Ltd.) as an antifoaming agent is coarsely kneaded, and then kneaded three times using a three-roll mill to perform main kneading. A composition containing polyurethane (2) uniformly mixed (hereinafter referred to as main agent composition A3) was obtained.
In addition to 255 parts by mass of the main agent composition A3, 35.14 parts by mass of the curing agent solution B1 and a silica hybrid / epoxy group-containing compound having a structure represented by the formula (26) (trade name, manufactured by Arakawa Chemical Industries, Ltd.) : Composeran E102B, dipropylene glycol dimethyl ether solution having a solid content concentration of 50% by mass) was added 17.57 parts by mass, followed by stirring with a resin mixer, and further γ-butyrolactone: diethylene glycol diethyl ether = 70: 30 (mass ratio) The viscosity was adjusted with a mixed solvent of diethylene glycol diethyl ether to obtain a thermosetting composition (hereinafter referred to as thermosetting composition G3).

(Example formulation 4)
216 parts by mass of the main agent composition A1 and 15.2 parts by mass of the curing agent solution B1, 1.0 part by mass of an antifoaming agent (product name: TSA750S, manufactured by Momentive Performance Materials Japan GK) and a formula (26 ) And 9.0 parts by mass of a silica hybrid / epoxy group-containing compound having a structure represented by (Arakawa Chemical Industries, Ltd., trade name: Composeran E102B, dipropylene glycol dimethyl ether solution having a solid content of 50% by mass) The mixture was thoroughly stirred using a spatula. Thereafter, a viscosity adjustment is performed by adding a mixed solvent of γ-butyrolactone: diethylene glycol diethyl ether = 85: 15 (mass ratio) necessary for adjusting the thixotropy index to 1.3. , Written as thermosetting composition G4).

(Example formulation 5)
In 280 parts by mass of the main agent composition A2, 35.14 parts by mass of the curing agent solution B1 and a silica hybrid / epoxy group-containing compound having a structure represented by the formula (26) (trade name, manufactured by Arakawa Chemical Industries, Ltd.) : Composeran E102B, dipropylene glycol dimethyl ether solution having a solid concentration of 50% by mass) is added 9.0 parts by mass, followed by stirring with a resin mixer, and further γ-butyrolactone: diethylene glycol diethyl ether = 70: 30 (mass ratio). The viscosity was adjusted with a mixed solvent of diethylene glycol diethyl ether to obtain a thermosetting composition (hereinafter referred to as thermosetting composition G5).

(Example formulation 6)
To 255 parts by mass of the main agent composition A3, 7.7 parts by mass of an epoxy group-containing compound (manufactured by Japan Epoxy Resin Co., Ltd., trade name: jER604, epoxy equivalent 120 g / eq) having the following formula (27) as a main component, 14.0 parts by mass of a silica hybrid / epoxy group-containing compound having a structure represented by the formula (26) (Arakawa Chemical Industries, Ltd., trade name: Composeran E102B, dipropylene glycol dimethyl ether solution having a solid content concentration of 50% by mass) The mixture was then stirred with a resin mixer, and the viscosity was adjusted with a mixed solvent diethylene glycol diethyl ether of γ-butyrolactone: diethylene glycol diethyl ether = 70: 30 (mass ratio), and a thermosetting composition (hereinafter referred to as thermosetting). This is referred to as composition G6.).

(Example formulation 7)
In 280 parts by mass of the main agent composition A2, 35.14 parts by mass of the curing agent solution B1 and 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-403) 0.7 parts by mass The viscosity was adjusted with a mixed solvent diethylene glycol diethyl ether of γ-butyrolactone: diethylene glycol diethyl ether = 70: 30 (mass ratio), and a thermosetting composition (hereinafter, thermosetting) was added. To be referred to as sex composition G7).

(Comparative Formulation Example 1)
35.14 parts by mass of the curing agent solution B1 is added to 255 parts by mass of the main agent composition A3, followed by stirring with a resin mixer, and further mixing with γ-butyrolactone: diethylene glycol diethyl ether = 70: 30 (mass ratio). The viscosity was adjusted with a solvent diethylene glycol diethyl ether to obtain a thermosetting composition (hereinafter referred to as thermosetting composition H1).

(Comparative Formulation Example 2)
To 255 parts by mass of the main agent composition A3, 7.7 parts by mass of an epoxy group-containing compound (Japan Epoxy Resin Co., Ltd., trade name: jER604, epoxy equivalent 120 g / eq) having the formula (27) as a main component is added. Subsequently, the mixture was stirred with a resin mixer, and the viscosity was adjusted with a mixed solvent diethylene glycol diethyl ether of γ-butyrolactone: diethylene glycol diethyl ether = 70: 30 (mass ratio), and a thermosetting composition (hereinafter referred to as thermosetting composition H2). Was obtained.)

<Evaluation of adhesion to copper substrate with tin plating>
(Creation of tin-plated copper substrate)
To create a tin-plated copper substrate, first, a copper substrate (S'PERFLEX / NT-L50, manufactured by Sumitomo Metal Mining Co., Ltd.) was used, and an IPC clean 91 (Okuno Pharmaceutical Co., Ltd.) having a concentration of 100 mL / L. Manufactured), immersed in an aqueous solution (30 ° C.) for 1 minute, then immersed in a 10 mass% H ₂ SO ₄ aqueous solution (23 ° C.) for 1 minute, and then electroless tin plating solution (LT-34, Rohm and -Made by Hearth Japan Co., Ltd.) for 4 minutes, further immersed in deionized water at 70 ° C for 3 minutes, and then dried at 120 ° C for 90 minutes using a hot-air circulating dryer, to give a tin plating treatment A copper substrate is obtained.
(Preparation of samples for adhesion evaluation)
The sample was prepared by applying the thermosetting resin composition onto the tin-plated copper substrate by screen printing with a # 250 mesh polyester plate and holding it at room temperature for 5 minutes or more in an air atmosphere. A sample having a coating thickness of 10 to 15 μm was obtained by heating at 150 ° C. for 1 hour and subsequently heating at 150 ° C. for 2 hours.
(Adhesion test method)
ACF tape (CP9420IS, manufactured by Sony Chemical Co., Ltd.) having a width of 2 mm and a length of about 30 mm is used in the center of a green epoxy substrate cut to 20 × 110 mm using an ACF thermocompression bonding apparatus PHC-500 (manufactured by Seiwa Seisakusho Co., Ltd.). Temporary pressure bonding was performed at 120 ° C. and 100 N for 2 seconds. The release paper of the temporarily pressed ACF tape was removed, and the cured film side of the sample cut to the same size as the green epoxy substrate was pressed against the ACF tape for 16.5 seconds under the conditions of 245 ° C. and 200 N. The green epoxy substrate and sample that were pressure-bonded via ACF tape were placed on a tensile testing machine (EZ Test / CE, manufactured by Shimadzu Corp.) equipped with a 90 ° peeling jig for printed boards. It installed so that it might become a sample and peel strength was measured at the speed of 50 mm / min. Further, the width (mm) at which the resin composition of the peeled sample was peeled was measured, and the 90 ° peel strength (N / cm) was determined.
The results are shown in Table 1.

<Evaluation of adhesion to polyimide film>
(Preparation of samples for adhesion evaluation)
Samples were prepared by applying the thermosetting resin composition on a polyimide film (Kapton (registered trademark) 150EN, manufactured by Toray DuPont Co., Ltd.) by screen printing with a # 250 mesh polyester plate for 5 minutes or more at room temperature. The sample having a coating film thickness of 10 to 15 μm was obtained by holding and heating in an air atmosphere at 120 ° C. for 1 hour and subsequently heating at 150 ° C. for 2 hours.
(Adhesion test method)
An ACF tape (CP9420IS, manufactured by Sony Chemical & Information Device Co., Ltd.) having a width of 2 mm and a length of about 30 mm is placed in the center of a green epoxy substrate cut to 20 × 110 mm, and an ACF thermocompression bonding apparatus PHC-500 (manufactured by Seiwa Corporation). ) Was temporarily pressed for 2 seconds under the conditions of 120 ° C. and 100 N. The release paper of the temporarily pressed ACF tape was removed, and the cured film side of the sample cut to the same size as the green epoxy substrate was pressed against the ACF tape for 16.5 seconds under the conditions of 238 ° C. and 200 N. The green epoxy substrate and sample that were pressure-bonded via ACF tape were placed on a tensile testing machine (EZ Test / CE, manufactured by Shimadzu Corp.) equipped with a 90 ° peeling jig for printed boards. It installed so that it might become a sample and peel strength was measured at the speed of 50 mm / min. Further, the width (mm) at which the resin composition of the peeled sample was peeled was measured, and the 90 ° peel strength (N / cm) was determined.
The results are shown in Table 1.

<Evaluation of warpage>
The curable composition G1 was applied to the substrate by screen printing, and cured by placing it in a hot air circulating dryer at 80 ° C. for 30 minutes and then placing it in a hot air circulating dryer at 120 ° C. for 60 minutes. A 38 μm-thick polyimide film [Kapton (registered trademark) 150EN, manufactured by Toray DuPont Co., Ltd.] was used as the substrate.
About the coating film which apply | coated the curable composition and was hardened | cured using the dryer, it cut with a circle cutter to 50 mmphi. What is cut into a circle exhibits a deformation in which the vicinity of the center warps in a convex or concave shape. After leaving the test piece at a temperature of 23 ± 0.5 ° C. and a humidity of 60 ± 5% RH for 12 hours or more, the test piece is left in a convex state, and the portion that is most warped from the plane, The height of the warp from the plane was measured using a length meter and averaged at two locations that were symmetric with respect to the center of. The sign represents the direction of warping, and when left in a downwardly convex state, the case where the cured film is on the upper side with respect to the polyimide film is “+”, and the case where the cured film is on the lower side is “−”.
The results are shown in Table 1.
Moreover, the same evaluation was performed using curable composition G2-curable composition G7, curable composition H1, and curable composition H2.
The results are also shown in Table 1.

<Evaluation of flexibility>
A flexible copper-clad laminate (made by Sumitomo Metal Mining Co., Ltd., grade name: Esperflex, copper thickness: 8 μm, polyimide thickness: 38 μm) on copper with a width of 75 mm, a length of 110 mm, and a cured coating film The curable composition G1 was applied by screen printing so as to have a thickness of 15 μm, held at room temperature for 10 minutes, and cured by placing it in a 120 ° C. hot air circulation dryer for 60 minutes. The PET film on the back of the prepared test piece was peeled off, cut into a strip shape with a width of 10 mm with a cutter knife, bent about 180 degrees so that the coating surface was on the outside, and 0.5 ± 0 using a compressor. Compressed at 2 MPa for 3 seconds. The bent part was bent and observed with a 30-fold microscope to confirm the presence or absence of cracks.
The results are shown in Table 1.
Moreover, the same evaluation was performed using curable composition G2-curable composition G7, curable composition H1, and curable composition H2.
The results are also shown in Table 1.

<Evaluation of long-term electrical insulation reliability>
A substrate having a fine comb pattern shape described in JPCA-ET01, manufactured by etching a flexible copper-clad laminate (manufactured by Sumitomo Metal Mining Co., Ltd., grade name: Esperflex, copper thickness: 8 μm, polyimide thickness: 38 μm) Copper wiring width / inter-copper wiring width = 8 μm / 12 μm) on a flexible wiring board subjected to a tin plating process, a thickness of 15 μm from the polyimide surface (after drying) by curable composition G1 by screen printing ) And placed in an 80 ° C. hot air circulation dryer for 30 minutes, and then placed in a 120 ° C. hot air circulation dryer for 120 minutes for curing.
Using this test piece, a bias voltage of 60 V was applied, and a temperature and humidity steady test under conditions of a temperature of 85 ° C. and a humidity of 85% RH was performed using MIGRATION TESTER MODEL MIG-8600 (manufactured by IMV). Table 1 shows the resistance values 10 hours, 500 hours, and 1000 hours after the start of the temperature and humidity steady test.
Moreover, the same evaluation was performed using curable composition G2-curable composition G7, curable composition H1, and curable composition H2.
The results are also shown in Table 1.

  From the results of Table 1, by using the thermosetting composition of the present invention (I), long-term electrical insulation characteristics can be expressed while maintaining a high level of resistance value, and good adhesion to a flexible wiring board. A thermosetting composition for a protective film of a wiring board capable of obtaining (that is, good adhesion to polyimide film and tin-plated copper), and a protective film for a wiring board obtained by curing the composition Can provide.

  The thermosetting composition for a protective film of a wiring board of the present invention is suitably used for production of a flexible wiring board.

Claims (15)

Thermosetting composition for protective film of wiring board comprising epoxy group-containing compound having alkoxysilyl group in molecule, polyurethane having carboxyl group and structural unit represented by following formula (1) and solvent as essential components .

(In the formula, R ¹ represents an alkylene group having 3 to 18 carbon atoms, and n represents an integer of 1 or more.) The polyurethane having a carboxyl group and having a structural unit represented by the formula (1) is a polyurethane polyimide obtained by reacting raw material components essentially comprising the following components (a) to (d): The thermosetting composition for protective films of a wiring board according to claim 1.
Component (a) Diisocyanate Component (b) (Poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms Component (c) Diol having a carboxyl group Component (d) Shown by the following formula (2) Bifunctional hydroxyl-terminated imide

Wherein R ² and R ³ each independently represents a divalent aliphatic or aromatic hydrocarbon group, and Y ¹ represents a tetravalent organic group derived from a tetracarboxylic acid or an acid anhydride group thereof. X ¹ represents a divalent organic group derived from diamine or diisocyanate, and m is an integer of 0 to 20.) A polyurethane having a carboxyl group and a structural unit represented by the formula (1) is reacted with raw material components essential for the following component (a), component (b), component (c) and component (e). The thermosetting composition for a protective film of a wiring board according to claim 1, which is a polyurethane obtained.
Component (a) Diisocyanate Component (b) (Poly) carbonate polyol having an organic residue derived from a diol having 3 to 18 carbon atoms Component (c) Diol having a carboxyl group Component (e) 3 hydroxyl groups in one molecule Compounds with more than   The epoxy group-containing compound having an alkoxysilyl group in the molecule is a compound having an alkoxysilyl group and two or more epoxy groups in the molecule. The thermosetting composition for protective films of the described wiring board.   Furthermore, the epoxy-containing compound which has a tricyclodecane structure is included, The thermosetting composition for protective films of the wiring board of any one of Claims 1-4 characterized by the above-mentioned. The epoxy-containing compound having a tricyclodecane structure has a tricyclo [5.2.1.0 ^2,6 ] decane structure or a tricyclo [3.3.1.1 ^3,7 ] decane structure, and an aromatic ring structure The thermosetting composition for a protective film of a wiring board according to claim 5, wherein the composition is an epoxy-containing compound. An epoxy-containing compound having a tricyclo [5.2.1.0 ^2,6 ] decane structure or a tricyclo [3.3.1.1 ^3,7 ] decane structure and having an aromatic ring structure is represented by the following formula (3 The thermosetting composition for a protective film of a wiring board according to claim 6, wherein the composition is a compound represented by

(In the formula, l represents 0 or an integer of 1 or more.)   The wiring board according to any one of claims 1 to 7, wherein the solvent is a mixed solvent containing two or more kinds of solvents having boiling points of 150 ° C or higher and 250 ° C or lower under atmospheric pressure. Thermosetting composition for protective film.   The solvent is a mixed solvent containing at least one solvent having a boiling point of 170 ° C. or more and less than 200 ° C. and at least one solvent having a boiling point of 200 ° C. or more and 220 ° C. or less under atmospheric pressure. The thermosetting composition for protective films of the wiring board of any one of Claims 1-7. The solvent is a mixed solvent containing at least one solvent selected from the following group A and at least one solvent selected from the following group B as essential components: The thermosetting composition for protective films of the wiring board of any one of Claims 1.
Group A: Diethylene glycol diethyl ether (boiling point 189 ° C.), diethylene glycol ethyl methyl ether (boiling point 176 ° C.), dipropylene glycol dimethyl ether (boiling point 171 ° C.), 3-methoxybutyl acetate (boiling point 171 ° C.), ethylene glycol monobutyl ether acetate (boiling point) 192 ° C)
Group B: Diethylene glycol butyl methyl ether (boiling point 212 ° C.), tripropylene glycol dimethyl ether (boiling point 215 ° C.), triethylene glycol dimethyl ether (boiling point 216 ° C.), ethylene glycol dibutyl ether (boiling point 203 ° C.), diethylene glycol monoethyl ether acetate (boiling point) 217 ° C.), γ-butyrolactone (boiling point 204 ° C.)   Furthermore, the thermosetting composition for protective films of the wiring board of any one of Claims 1-10 containing a hardening accelerator.   The wiring accelerator according to claim 11, wherein the curing accelerator is one or more selected from the group consisting of melamine, imidazole compounds, cycloamidine compounds and derivatives thereof, phosphine compounds, and amine compounds. A thermosetting composition for a protective film of a plate.   Furthermore, inorganic fine particle and / or organic fine particle are contained, The thermosetting composition for protective films of the wiring board of any one of Claims 1-12 characterized by the above-mentioned.   The protective film of a wiring board obtained by hardening | curing the thermosetting composition for protective films of the wiring board of any one of Claims 1-13.   A part of or all of a surface of a flexible wiring board in which wiring is formed on a flexible substrate is covered with the protective film of the wiring board according to claim 14. A flexible wiring board covered with a film.