JPWO2017183496A1 - Curable composition, cured film and overcoat film using the composition - Google Patents

Abstract

[Problem] When a protective film for a flexible wiring board is formed, while maintaining high electrical insulation reliability at high temperatures and high humidity, warping is sufficiently suppressed and thermosetting is also excellent in bending resistance To provide a resin composition.
[Solution] The curable composition of the present invention comprises (Component A) a functional group having a specific structural unit, having at least one of an imide bond and an amide bond, and reacting with a curing agent. A compound having (Component B) a curing agent, and (Component C) an organic solvent. (Component A) is (raw material a) a trivalent and / or tetravalent polycarboxylic acid derivative having an acid anhydride group, (raw material b) a polyol represented by the following formula (2), and (raw material c) poly It is preferable to contain the compound obtained by making it react using an isocyanate as an essential component.

Description

  The present invention relates to a thermosetting resin composition, a method for forming a protective film for a flexible wiring board, a flexible wiring board and an electronic component, and a method for manufacturing the flexible wiring board.

  In recent years, in the field of electronic parts, resin compositions (for example, sealants, solder resists, etc.) used for electronic parts have better heat resistance in order to cope with downsizing, thinning, and speeding up. It is required to have electrical properties and moisture resistance. Therefore, as a resin constituting the resin composition, a polyimide resin, a polyamideimide resin, or a polyamide resin has been used instead of an epoxy resin. However, these resins have a rigid resin structure and a cured film lacks flexibility. Therefore, when it uses for a thin film base material, there exists a problem that the base material after hardening is easy to warp largely, and is inferior in flexibility.

  In order to improve the warpage and flexibility of the above-mentioned resins, it has been studied so far to make the resin flexible and to have a low elastic modulus, and various modified polyamideimide resins have been proposed. (See, for example, Patent Documents 1, 2, and 3).

  On the other hand, Patent Document 4 discloses a thermosetting resin composition that is improved in low warpage, flexibility, solder heat resistance, and tin plating resistance. The thermosetting resin composition of Patent Document 4 has excellent performance in terms of electrical insulation characteristics that maintain high electrical characteristics at high temperatures and high humidity.

  However, in recent years, with the miniaturization of wiring, there has been a problem that wiring breakage occurs during transportation when the display panel connected with the flexible wiring board is set in the housing in another place. Therefore, a protective film having a protective function against wiring breakage (hereinafter sometimes referred to as “bending resistance”) has been desired.

  Patent Document 5 discloses a thermosetting resin composition containing a polyamideimide-modified polyurethane, a curing agent, and an organic solvent having low warpage, flexibility, and bending resistance. Here, low warpage, flexibility, and electrical insulation characteristics under high temperature and high humidity are measured.

  However, even this thermosetting resin composition does not completely satisfy the bending resistance desired in the market, and an electric insulating protective film having further higher bending resistance has been desired.

JP 62-106960 A Japanese Patent Laid-Open No. 8-12763 JP-A-7-196798 JP 2006-117922 A JP-A-2015-147940

  However, with regard to the resin that forms the protective film of the flexible wiring board, the conventional resin composition with improved warpage and flexibility is easy to infiltrate water molecules under high temperature and high humidity, and maintains high electrical characteristics. It was difficult. In order to impart high electrical properties, it is considered effective to introduce a rigid component into the resin structure and to have a high glass transition temperature, but according to this technique, the substrate after curing tends to warp greatly, In addition, problems such as poor flexibility occur.

  Further, the thermosetting resin composition described in Patent Document 4 provides a protective function against wiring breakage, although some improvement is recognized in terms of low warpage, flexibility, solder heat resistance and tin plating resistance. It was difficult.

Moreover, although the thermosetting resin composition described in Patent Document 5 has a certain degree of bending resistance, it is still not sufficient.
Therefore, when the protective film of the flexible wiring board is formed, the present invention suppresses warping sufficiently while maintaining high electrical insulation reliability under high temperature and high humidity, and is excellent in bending resistance. The main object is to provide a thermosetting resin composition.

  As a result of repeated studies to solve the above problems, the present inventors have flexible a curable composition having a specific structure and a compound having an imide bond and / or an amide bond as an essential component. When printed on a wiring board, the warp of the flexible wiring board when the printed curable composition is cured is small, and the protective film containing a cured product of this curable composition has flexibility and long-term electrical insulation properties. The present invention has been completed by finding that it has an excellent effect of suppressing breakage of a large wiring when the flexible wiring board covered with the protective film is shaken.

That is, the present invention relates to the following matters.
[1] (Component A) A compound having a structural unit represented by the following formula (1), having a bond of at least one of an imide bond and an amide bond, and having a functional group that reacts with a curing agent,
A curable composition comprising (Component B) a curing agent, and (Component C) an organic solvent.

（式（１）中、Ｒ¹は、それぞれ独立に３〜３６個の炭素を有するジオールから誘導される有機残基を表し、Ｒ²は、それぞれ独立にフェニレン基または置換基を有するフェニレン基を表す。）

(In formula (1), each R ¹ independently represents an organic residue derived from a diol having 3 to 36 carbon atoms, and each R ² independently represents a phenylene group or a phenylene group having a substituent. Represents.)

  [2] The curability according to [1], wherein the functional group that reacts with the curing agent is at least one of a carboxyl group, a hydroxyl group, an acid anhydride group, an isocyanato group, an amide group, and an amino group. Composition.

  [3] (Component A) is (raw material a) a trivalent and / or tetravalent polycarboxylic acid derivative having an acid anhydride group, (raw material b) a polyol represented by the following formula (2), and (raw material) c) The curable composition according to [1] or [2], comprising a compound obtained by reacting polyisocyanate as an essential component.

（式（２）中、（ｎ＋１）個のＲ¹は、それぞれ独立に炭素数３〜３６のジオールから誘導される有機残基を表し、ｎ個のＲ²は、それぞれ独立にフェニレン基または置換基を有するフェニレン基を表し、ｎは、１〜６０の整数を表す。）

(In the formula (2), (n + 1 ) number of R ¹ represents an organic residue derived independently from diols 3 to 36 carbon atoms, n number of R ² is a phenylene group or a substituted independently Represents a phenylene group having a group, and n represents an integer of 1 to 60.)

  In addition, (Component A) in the curable composition defined by [3] is (raw material a) trivalent and / or tetravalent polycarboxylic acid derivative having an acid anhydride group, (raw material b) formula ( The polyol represented by 2) and (raw material c) polyisocyanate are used as raw materials, and the reaction is possible between many compounds corresponding to (raw material a), (raw material b), and (raw material c). Moreover, the polymer obtained will also change if the compounding ratio and reaction conditions of each monomer are changed. Therefore, the structure of the component A obtained is extremely diverse, and it is difficult to define with a specific structure, it can be said that it is common technical knowledge of those skilled in the art. And if the structure cannot be specified, the characteristics cannot be specified. That is, the polymerization composition specified in [3] cannot be specified by its structure or characteristics, and can be specified for the first time by a process (production method). Or we think there are circumstances where it is impossible or nearly impractical to identify directly by property.

  [3 ′] (Component A) is at least (raw material a) a trivalent and / or tetravalent polycarboxylic acid derivative having an acid anhydride group, (raw material b) a polyol represented by the following formula (2), And (raw material c) a curable composition as described in [1] or [2], comprising a reaction product comprising polyisocyanate.

（式（２）中、（ｎ＋１）個のＲ¹は、それぞれ独立に炭素数３〜３６のジオールから誘導される有機残基を表し、ｎ個のＲ²は、それぞれ独立にフェニレン基または置換基を有するフェニレン基を表し、ｎは、１〜６０の整数を表す。）

(In the formula (2), (n + 1 ) number of R ¹ represents an organic residue derived independently from diols 3 to 36 carbon atoms, n number of R ² is a phenylene group or a substituted independently Represents a phenylene group having a group, and n represents an integer of 1 to 60.)

[4] The curable composition according to any one of [1] to [3], wherein (Component A) further has a urethane bond.
[5] The curable composition according to any one of [1] to [4], wherein (Component A) has an acid value of 10 to 50 mgKOH / g.
[6] The curable composition according to any one of [1] to [5], wherein (Component B) contains a compound having two or more epoxy groups per molecule.
[7] (Component C) is at least one organic solvent selected from the group consisting of ether solvents, ester solvents, ketone solvents, and aromatic hydrocarbon solvents [1] -The curable composition in any one of [6].
[8] Furthermore,
(Component D) The curable composition according to any one of [1] to [7], comprising at least one fine particle selected from the group consisting of inorganic fine particles and organic fine particles.
[9] Any one of [1] to [8], wherein the total amount of the component (A) and the component (B) is 100 parts by mass, and the component (B) is included in an amount of 1 to 55 parts by mass. The curable composition according to item.
[10] Total amount of component (A), component (B), component (C), and component (D) (when component (D) is not included, component (A), component (B), and component ( The curable composition according to any one of [1] to [9], wherein 25 to 75 parts by mass of the component (C) is included when the total amount of C) is 100 parts by mass.

[11] A cured product of the curable composition according to any one of [1] to [10].
[12] The curable composition according to any one of [1] to [10] is applied to part or all of a surface of a flexible wiring board in which wiring is formed on a flexible substrate. An overcoat film for a flexible wiring board obtained by curing.
[13] A flexible wiring board in which wiring is formed on a flexible substrate is partially or entirely covered with the overcoat film described in [12]. Flexible wiring board.
[14] The flexible wiring board according to [13], wherein the wiring is tin-plated copper wiring.
[15] A method for producing a flexible wiring board covered with an overcoat film, comprising the following (Step 1) and (Step 3) and optionally (Step 2);
(Process 1)
The process of forming a printed film on this pattern by printing the curable composition in any one of [1]-[10] on at least one part of the wiring pattern part of a flexible wiring board (process 2)
A step of evaporating a part or all of the solvent in the printed film by placing the printed film obtained in step 1 in an atmosphere of 40 to 100 ° C. (step 3)
A step of curing the printed film obtained in step 1 or the printed film obtained in step 2 at 100 to 170 ° C. to form an overcoat film.
[16] An electronic component having the cured film according to [11].
Note that the expression “(n + 1) R ¹ 's are independent of each other” in this specification means that (n + 1) R ¹ have the same structure even if they all have the same structure. This means that it does not matter whether the other part has a different structure or a different structure. Similarly, the expression “n R ² 's are independent of each other” described in the present specification is the same, even though all of the R R ² have the same structure, Even if some of them have different structures, all of them have different structures.

  By curing the curable composition of the present invention, a protective film excellent in low warpage, flexibility, and long-term insulation reliability is obtained, and when the flexible wiring board covered with the cured film is shaken. It is possible to provide a protective film having a great effect of suppressing wiring breakage.

  Further, the present invention is a protective film made of a cured product of the curable composition, and a flexible wiring board covered with the protective film, and warping is sufficiently suppressed while maintaining high insulation reliability. In addition, a flexible wiring board having excellent flexibility can be provided.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.
The present invention
(Component A) A compound having a structural unit represented by the following formula (1), having a bond of at least one of an imide bond and an amide bond, and having a functional group that reacts with a curing agent,
(Component B) A curable composition containing a curing agent, and (Component C) an organic solvent.

（式（１）中、Ｒ¹は、それぞれ独立に３〜３６個の炭素を有するジオールから誘導される有機残基を表し、Ｒ²は、それぞれ独立にフェニレン基または置換基を有するフェニレン基を表す。）
本発明の硬化性組成物の必須成分である（成分Ａ）は、式（１）で表される構造単位を有し、かつイミド結合

(In formula (1), each R ¹ independently represents an organic residue derived from a diol having 3 to 36 carbon atoms, and each R ² independently represents a phenylene group or a phenylene group having a substituent. Represents.)
(Component A) which is an essential component of the curable composition of the present invention has a structural unit represented by the formula (1) and has an imide bond.

およびアミド結合（−Ｃ（＝Ｏ）−ＮＨ−）の少なくとも１方の結合を有する化合物である。（成分Ａ）は、さらにウレタン結合（−Ｏ−Ｃ（＝Ｏ）−ＮＨ−）を有していてもよい。さらに(成分Ａ)は、硬化剤と反応する官能基を有している。硬化剤と反応する好ましい官能基としては、カルボキシル基、水酸基、酸無水物基、イソシアナト基、アミド基、アミノ基の少なくとも1種の官能基が挙げられる。イソシアナト基を有する場合には、イソシアナト基はブロック化剤で保護されていることが好ましい。またその他の基においてもブロック化剤で保護されていてもよく、ブロック体が外れて反応するものは官能基とみなすものとする。波線は結合の末端で、他の結合との結合部位を表す。

And a compound having at least one bond of an amide bond (—C (═O) —NH—). (Component A) may further have a urethane bond (—O—C (═O) —NH—). Furthermore, (Component A) has a functional group that reacts with the curing agent. Preferable functional groups that react with the curing agent include at least one functional group of a carboxyl group, a hydroxyl group, an acid anhydride group, an isocyanato group, an amide group, and an amino group. When it has an isocyanato group, the isocyanato group is preferably protected with a blocking agent. In addition, other groups may be protected with a blocking agent, and those that react with the block body removed are regarded as functional groups. The wavy line is the end of the bond and represents the binding site with other bonds.

In Formula (1), R ¹ is an organic residue derived from a diol having 3 to 36 carbon atoms. In other words, the organic residue derived from the diol is a divalent group in which two hydroxy groups are removed from the diol.

Examples of the diol having 3 to 36 carbons include 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5- Pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,9- Chain diols such as nonanediol, 1,10-decanediol, 1,12-dodecanediol, hydrogenated dimer (C36) diol, diethylene glycol, triethylene glycol,
5-membered ring diols such as 1,2-cyclopentanedimethanol, 1,3-cyclopentanedimethanol and bis (hydroxymethyl) tricyclo [5.2.1.0] decane, and 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, and 2,2-bis (4-hydroxycyclohexyl) -The diol etc. which have alicyclic structures, such as 6-membered ring diols, such as propane, can be mentioned.

R ¹ is preferably a hydrocarbon group having 3 to 18 carbon atoms and a chain structure, and more preferably a hydrocarbon group having 4 to 9 carbon atoms and a chain structure. Particularly preferred is a hydrocarbon group having 4 to 6 carbon atoms and a chain structure. That is, preferable diols capable of deriving the organic residue of R ¹ include, for example, 1,3-propanediol, 1,2-propanediol, 1,4-ditandiol, 2-methyl-1, 3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1, Examples include 8-octanediol, 1,9-nonanediol, and 1,10-decanediol, and more preferable diols include, for example, 1,4-ditandiol, 2-methyl-1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, 1,9-no Diols, 2-methyl-1,8-octanediol, 1,9-nonanediol, and particularly preferred diols include, for example, 1,4-ditandiol, 2-methyl-1,3-propanediol. 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, and most preferred diols include 1,6-hexanediol, 3-methyl-1, 5-pentanediol.

In formula (1), R ² independently represents a phenylene group or a phenylene group having a substituent. Examples of the phenylene group include a 1,2-phenylene group, a 1,3-phenylene group, and a 1,4-phenylene group. Examples of the substituent of the phenylene group having a substituent include an alkyl group having 1 to 10 carbon atoms, specifically, a 3-methyl-1,2-phenylene group and a 4-methyl-1,2-phenylene group. 4-methyl-1,3-phenylene group, 2-methyl-1,4-phenylene group, 3-ethyl-1,2-phenylene group, 4-ethyl-1,2-phenylene group, 4-ethyl-1 , 3-phenylene group, 2-ethyl-1,4-phenylene group, and the like, examples thereof include a phenylene group having an alkyl group. Examples of the phenylene group having a substituent include 3-bromo-1,2-phenylene group, 4-bromo-1,2-phenylene group, 4-bromo-1,3-phenylene group, and 2-bromo-1,4. Halogens such as -phenylene group, 3-chloro-1,2-phenylene group, 4-chloro-1,2-phenylene group, 4-chloro-1,3-phenylene group, 2-chloro-1,4-phenylene group A phenylene group containing

  Among these, preferred are 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, and phenylene group having an alkyl group as a substituent. A 2-phenylene group, a 1,3-phenylene group, and a 1,4-phenylene group are preferable, and a 1,2-phenylene group and a 1,3-phenylene group are particularly preferable.

Further, the most preferred combination of R ¹ and R ^2, in the case of R ² is 1,2-phenylene group, induction R ¹ is 1,6-hexanediol or 3-methyl-1,5-pentanediol When R ² is a 1,3-phenylene group, R ¹ is an organic residue derived from 3-methyl-1,5-pentanediol.

Next, a synthesis method of (Component A) will be described.
(Component A) can be synthesized, for example, by the following method.
(Method 1) (Raw material b) Polyol represented by the following formula (2)

（式（２）中、（ｎ＋１）個のＲ¹はそれぞれ独立に炭素数３〜３６のジオールから誘導される有機残基を表し、ｎ個のＲ²は、それぞれ独立にフェニレン基または置換基を有するフェニレン基を表し、ｎは、独立に１〜６０の整数を表す。）
（原料ｃ）ポリイソシアネートとを反応させて、ウレタン結合を有しかつ末端にイソシアナト基を有する化合物を得、得たウレタン結合を有しかつ末端にイソシアナト基を有する化合物を含むポリイソシアネートと（原料ａ）酸無水物基(下図)

(In the formula (2), (n + 1) R ^{1 's} each independently represents an organic residue derived from a diol having 3 to 36 carbon atoms, and each of the n R ² ' s independently represents a phenylene group or a substituent. And n represents an integer of 1 to 60 independently.)
(Raw material c) A polyisocyanate is reacted with polyisocyanate to obtain a compound having a urethane bond and having an isocyanato group at the terminal, and the obtained polyisocyanate containing a compound having a urethane bond and having an isocyanato group at the terminal (raw material a) Acid anhydride group (see below)

を有する３価および／または４価のポリカルボン酸誘導体とを反応させる。

Is reacted with a trivalent and / or tetravalent polycarboxylic acid derivative.

  (Method 2) (raw material c) polyisocyanate and (raw material a) a trivalent and / or tetravalent polycarboxylic acid derivative having an acid anhydride group are reacted to bond at least one of an imide bond and an amide bond A polyisocyanate having the following formula (2) is reacted with a polyol represented by the formula (2).

  (Method 3) (raw material c) polyisocyanate and (raw material a) a trivalent and / or tetravalent polycarboxylic acid derivative having an acid anhydride group are reacted to form at least one of an imide bond and an amide bond And a compound having an acid anhydride group and / or a carboxyl group at the terminal is obtained, and this is reacted with a polyol represented by (raw material b) formula (2).

In the synthesis method of (Method 1), first, (raw material b) a polyol represented by formula (2) and (raw material c) are reacted with polyisocyanate to have a urethane bond and an isocyanate group at the terminal. (Hereinafter referred to as “(A ¹ -1) compound”).

R ^1, R ² in the formula (2) are respectively the same as R ^1, R ² in the formula (1).
N in the formula (2) represents an integer of 1 to 60. As preferable n, it is an integer of 1-45, Most preferably, it is an integer of 1-30. The average value of n is preferably from 3 to 11, more preferably from 5 to 10.

The number average molecular weight of the diol of the formula (2) is preferably 500 to 5000, more preferably 750 to 4000, and particularly preferably 1000 to 3000.
The polyisocyanate (that is, (raw material c)) to be reacted with the polyol of (raw material b) is not particularly limited as long as it is a compound having two or more isocyanato groups. Specific examples of the polyisocyanate include 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis. (Isocyanatomethyl) cycloaliphatic polyisocyanates such as biuret of cyclohexane, norbornene diisocyanate and isophorone diisocyanate; diphenylmethane-2,4′-diisocyanate, 3,2′-dimethyldiphenylmethane-2,4′-diisocyanate, 3,3 '-Dimethyldiphenylmethane-2,4'-diisocyanate, 4,2'-dimethyldiphenylmethane-2,4'-diisocyanate, 4,3'-dimethyldiphenylmethane- , 4′-diisocyanate, 5,2′-dimethyldiphenylmethane-2,4′-diisocyanate, 5,3′-dimethyldiphenylmethane-2,4′-diisocyanate, 6,2′-dimethyldiphenylmethane-2,4′-diisocyanate 6,3′-dimethyldiphenylmethane-2,4′-diisocyanate, 3,2′-diethyldiphenylmethane-2,4′-diisocyanate, 3,3′-diethyldiphenylmethane-2,4′-diisocyanate, 4,2 ′ -Diethyldiphenylmethane-2,4'-diisocyanate, 4,3'-diethyldiphenylmethane-2,4'-diisocyanate, 5,2'-diethyldiphenylmethane-2,4'-diisocyanate, 5,3'-diethyldiphenylmethane-2 , 4'-diisocyanate, 6,2'-diethyldiphenyl Tan-2,4′-diisocyanate, 6,3′-diethyldiphenylmethane-2,4′-diisocyanate, 3,2′-dimethoxydiphenylmethane-2,4′-diisocyanate, 3,3′-dimethoxydiphenylmethane-2,4 '-Diisocyanate, 4,2'-dimethoxydiphenylmethane-2,4'-diisocyanate, 4,3'-dimethoxydiphenylmethane-2,4'-diisocyanate, 5,2'-dimethoxydiphenylmethane-2,4'-diisocyanate, 5 3,3′-dimethoxydiphenylmethane-2,4′-diisocyanate, 6,2′-dimethoxydiphenylmethane-2,4′-diisocyanate, 6,3′-dimethoxydiphenylmethane-2,4′-diisocyanate, diphenylmethane-4,4 ′ -Diisocyanate, diphenylmethane-3 , 3′-diisocyanate, diphenylmethane-3,4′-diisocyanate, diphenyl ether-4,4′-diisocyanate, benzophenone-4,4′-diisocyanate, diphenylsulfone-4,4′-diisocyanate, 2,4-tolylene diisocyanate Fragrance such as 2,6-tolylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, 1,5-naphthalene diisocyanate, 4,4 ′-[2,2bis (4-phenoxyphenyl) propane] diisocyanate A polyisocyanate having a ring;
Chain aliphatic polyisocyanates such as biuret of hexamethylene diisocyanate, lysine triisocyanate, lysine diisocyanate, hexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate and 2,2,4-trimethylhexanemethylene diisocyanate;
Examples thereof include polyisocyanates having a heterocyclic ring such as isocyanurate of isophorone diisocyanate and isocyanurate of hexamethylene diisocyanate, and these may be used alone or in combination of two or more.

  The reactivity between the synthesized compound having a urethane bond and an isocyanato group at the terminal and the trivalent and / or tetravalent polycarboxylic acid derivative having an acid anhydride group to be reacted thereafter (raw material a) In consideration, among these, polyisocyanates having an aromatic ring are preferable, and diphenylmethane-4,4′-diisocyanate, diphenylmethane-3,3′-diisocyanate, diphenylmethane-3,4 ′ are more preferable. -Polyisocyanates having an aromatic ring such as diisocyanate and diphenyl ether-4,4'-diisocyanate, and most preferably diphenylmethane-4,4'-diisocyanate.

  In addition, in the polyisocyanate, an isocyanato group may be stabilized with a blocking agent in order to avoid changes over time. Examples of the blocking agent include hydroxy acrylate, methanol, alcohols such as 2-butanone oxime, phenol, and oxime, but there is no particular limitation.

  The reaction of the polyol of (raw material b) and the polyisocyanate of (raw material c) can be carried out by heating and reacting them in the presence of an organic solvent, preferably a non-nitrogen-containing polar solvent.

  Examples of the non-nitrogen-containing polar solvent include ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and triethylene glycol diethyl ether; sulfur-containing solvents such as dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, and sulfolane. An ester solvent such as γ-butyrolactone and cellosolve acetate; a ketone solvent such as cyclohexanone and methyl ethyl ketone; and an aromatic hydrocarbon solvent such as toluene and xylene. These can be used alone or in combination of two or more.

Among the above solvents, it is preferable to select and use a solvent in which the resin to be generated can be dissolved.
Moreover, it is preferable to use what is suitable as a solvent of a thermosetting resin composition as it is after a synthesis | combination. Among these solvents, cyclohexanone, γ-butyrolactone, and diethylene glycol diethyl ether are particularly preferable in view of volatility and efficient reaction in a homogeneous system.

The amount of the solvent to be used, relative to (A ¹ -1) 100 parts by mass of the total amount of the raw materials for synthesizing the compounds is preferably 80 to 500 parts by weight. When the amount used is 80 to 500 parts by mass with respect to 100 parts by mass of the total amount of raw materials for synthesizing the (A ¹ -1) compound, the viscosity at the time of synthesis does not become too high, and synthesis is difficult due to inability to stir. It is preferable that the reaction rate is not extremely reduced.

  The reaction temperature is preferably 60 to 210 ° C, more preferably 70 to 190 ° C, and particularly preferably 80 to 180 ° C. If this temperature is less than 60 ° C, the reaction time tends to be too long, and if it exceeds 210 ° C, gelation tends to occur during the reaction. The reaction time can be appropriately selected depending on the capacity of the reaction vessel 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, cobalt, or a metalloid compound. The blending ratio at the time of reacting the polyol of (raw material b) and the polyisocyanate of (raw material c) is appropriately adjusted according to how many the number average molecular weight of the (A ¹ -1) compound to be produced is. However, since the terminal of the compound (A ¹ -1) to be generated is an isocyanato group, it is necessary that the number of hydroxyl groups in (raw material b) <the number of isocyanate groups in (raw material c).

When synthesizing a compound (A ¹ -1) having an isocyanato group at the terminal, the ratio between the number of isocyanato groups and the number of hydroxyl groups (the number of isocyanato groups / the number of hydroxyl groups) is preferably adjusted to be 1.01 or more. It is more preferable to adjust to 0.0 or less.

The number average molecular weight of the (A ¹ -1) compound having an isocyanato group at the terminal is preferably 500 to 30000, more preferably 1000 to 25000, and particularly preferably 1500 to 20000.

The (A ¹ -1) compound having an isocyanato group at the terminal and the (raw material a) trivalent and / or tetravalent polycarboxylic acid derivative having an acid anhydride group are reacted to form a urethane bond, an amide bond and / or Alternatively, a compound having an imide bond is generated. In addition, when (raw material a) is a trivalent polycarboxylic acid derivative having an acid anhydride group, it has one set of acid anhydride and one carboxyl group. When (raw material a) is a tetravalent polycarboxylic acid derivative having an acid anhydride group, it has two sets of acid anhydrides, or one set of acid anhydride groups and two carboxyl groups. . The carboxyl group may form a derivative by forming an ester bond with alcohol. Here, the polycarboxylic acid derivative means a polycarboxylic acid having an acid anhydride group or a derivative such as a carboxylic acid ester thereof.

  Although it does not specifically limit as a trivalent polycarboxylic acid derivative which has an acid anhydride group, For example, the compound represented by following General formula (3) or (4) can be mentioned.

（式（３）中、Ｒ³は、水素原子、炭素数１〜１０のアルキル基又はフェニル基を表す。
）

(In formula (3), R ³ represents a hydrogen atom, an alkyl group or a phenyl group having 1 to 10 carbon atoms.
)

（式（４）中、Ｒ⁴は、水素原子、炭素数１〜１０のアルキル基又はフェニル基を表し、Ｙ¹は、−ＣＨ₂−、−ＣＯ−、−ＳＯ₂−、または−Ｏ−を表す。）

(In formula (4), R ⁴ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group, and Y ¹ represents —CH ₂ —, —CO—, —SO ₂ —, or —O—. Represents.)

R ³ and R ⁴ are preferably a hydrogen atom, and Y 1 is preferably —CO— or —O—.
Among these, as the trivalent polycarboxylic acid derivative having an acid anhydride group, trimellitic anhydride is particularly preferable from the viewpoint of cost.
Although it does not specifically limit about the tetravalent polycarboxylic acid derivative which has an acid anhydride group, For example, the tetracarboxylic dianhydride represented by following General formula (5) can be mentioned. These can be used alone or in combination of two or more.

（式（５）中、Ｙ²は、４価の有機基を示す。）

(In formula (5), Y ² represents a tetravalent organic group.)

  The tetracarboxylic dianhydride represented by the formula (5) is not particularly limited. For example, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2 , 3,2 ′, 3′-benzophenone tetracarboxylic dianhydride, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenyltetracarboxylic dianhydride Anhydride, 2,2 ', 3,3'-diphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-di Carboxyphenyl) ethane dianhydride, bis 2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 3,4,9,10 -Perylenetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetra Carboxylic dianhydride, 1,2,4,5-naphthalene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, phenanthrene-1,8,9,10-tetracarboxylic Acid dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ) Dimethylsilane dianhydride, bis (3,4-dicarboxyphenyl) diphenylsilane dianhydride, 1,4-bis (3,4-dicarboxyphenyldimethylsilyl) benzene dianhydride, 1,3-bis ( 3,4-dicarboxyphenyl) -1,1,3,3-tetramethyldicyclohexane dianhydride, p-phenylbis (trimellitic acid monoester anhydride), ethylenetetracarboxylic dianhydride, 1, 2,3,4-butanetetracarboxylic dianhydride, decahodronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6, 7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetra Rubonic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, bis (exo-bicyclo [2,2,1] heptane-2,3-dicarboxylic anhydride) sulfone, bicyclo- ( 2,2,2) -oct (7) -ene-2,3,5,6-tetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] hexafluoropropane dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 1,4 -Bis (2-hydroxyhexafluoroisopropyl) benzenebis (trimellitic anhydride), 1,3-bis (2-hydroxyhexafluoroisopropyl) benzenebis (trimeric Acid water), 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, tetrahydrofuran-2,3,4,5-tetracarboxylic acid dianhydride 1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro-2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione, ethylene glycol bis ( Trimellitic anhydride) (also referred to as “ethylene glycol bisanhydro trimellitate” or “TMEG”).

  Preferably, the tetracarboxylic dianhydride is ethylene glycol bis (trimellitic anhydride) (TMEG), 3,3 ′, 4,4′-diphenyltetracarboxylic dianhydride (BPDA), pyromellitic dianhydride. Anhydride (PMDA), 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA), 4,4′-oxydiphthalic dianhydride (ODPA).

These tetracarboxylic dianhydrides may be used alone or in combination of two or more.
In Method 1, the (A ¹ -1) compound is reacted with the (raw material a) together with a polyisocyanate other than the (A ¹ -1) compound (hereinafter referred to as (A ¹ -2) compound). A compound having a urethane bond and an amide bond and / or an imide bond may be obtained. The (A ¹ -2) compound is not particularly limited as long as it is a polyisocyanate other than the (A ¹ -1) compound, and examples thereof include the (raw material c). These can be used individually by 1 type or in combination of 2 or more types. And the combined total of the acid anhydride group and a carboxyl group of the starting material a, the ratio of the total number of isocyanate groups of the combined isocyanate groups of isocyanate group and A ¹ in -2 in A ¹ -1 is not particularly limited, The range is preferably 0.9: 1.0 to 1.1: 1.0, and more preferably 0.95: 1.0 to 1.05: 1.0.

  In this embodiment, an amine compound can be used in combination with the polyisocyanate. As an amine compound, the compound which converted the isocyanato group in the said polyisocyanate conversion into the amino group is mentioned. Conversion of the isocyanato group to an amino group can be performed by a known method.

It is preferred 50 to 100 wt% of the total amount of (A ¹ -2) compound is an aromatic polyisocyanate. The aromatic polyisocyanate is particularly preferably diphenylmethane-4,4′-diisocyanate in consideration of the balance of solubility, mechanical properties, cost and the like.

In the synthesis method of (Method 2), first, (raw material c) polyisocyanate and (raw material a) a trivalent and / or tetravalent polycarboxylic acid derivative having an acid anhydride group are reacted to form an imide bond and an amide. A polyisocyanate having at least one bond (hereinafter referred to as “(A ² −1) compound”) is synthesized.

The blending ratio when reacting the (raw material c) polyisocyanate with the (raw material a) trivalent and / or tetravalent polycarboxylic acid derivative having an acid anhydride group is the ratio of the compound (A ² -1) to be produced. The number average molecular weight is appropriately adjusted depending on how much the molecular weight is made. However, since the terminal of the compound (A ² -1) to be generated is an isocyanato group, the total number of the acid anhydride groups and the number of carboxyl groups in (raw material a) <the total number of isocyanato groups in (raw material c). There is a need. Here, the number of carboxyl groups includes R ³ and R ⁴ as hydrogen atoms, such as —COOR ³ in the compound represented by formula (3) and —COOR ^{4 in} the compound represented by formula (4). Also includes the number of certain carboxyl groups.

Note that (raw material a) and (raw material c) used in the synthesis method of (Method 2) are the same as (raw material a) and (raw material c) used in the synthesis method of (Method 1), respectively. used. When synthesizing a compound (A ² -1) having an isocyanato group at the terminal, the ratio of the number of isocyanato groups, the number of acid anhydride groups and the total number of carboxyl groups (the number of isocyanato groups / the number of acid anhydride groups) The total number of carboxyl groups is preferably adjusted to be 1.01 or more, and is preferably adjusted to 2.0 or less.

The number average molecular weight of the (A ² -1) compound having an isocyanato group at the terminal is preferably 500 to 15000, more preferably 800 to 10,000, and particularly preferably 1,000 to 5,000.

Next, the (A ² -1) compound having an isocyanato group at the terminal is reacted with the polyol represented by (raw material b) formula (2) to have a urethane bond and an amide bond and / or an imide bond. A compound is formed.

Further, when reacting the (A ² -1) compound having an isocyanato group at the terminal with the polyol represented by (raw material b) formula (2), 2,2-dimethylolpropionic acid or 2,2-dioxy A polyol having a carboxyl group such as methylol butanoic acid can also be used together.

The total number of isocyanate groups in A ² -1, number of hydroxyl groups in the starting material b, and 2,2 number of hydroxyl groups in the polyol having a carboxyl group such as dimethylol propionic acid and 2,2-dimethylol butanoic acid The ratio of the total number of combined hydroxyl groups is not particularly limited, but when A ² -1 has an amide group, it may be in the range of 0.9: 1.0 to 1.1: 1.0. More preferably, it is the range of 0.95: 1.0 to 1.05: 1.0. When a polyol having no amide group in A ² -1 and having a carboxyl group such as 2,2-dimethylolpropionic acid or 2,2-dimethylolbutanoic acid is not used, 0.9. : 1.0 to 0.95: 1.0, or 1.0: 0.95 to 1.0: 0.9.

  The (raw material b) used in the synthesis method of (Method 2) can be the same as the (raw material b) described in (Method 1). Further, a polyol may be further added to form a urethane bond by a reaction between the terminal isocyanate group and the added polyol.

In the synthesis method of (Method 3), first, (raw material c) polyisocyanate and (raw material a) a trivalent and / or tetravalent polycarboxylic acid derivative having an acid anhydride group are reacted to form an imide bond and an amide. A compound having at least one of the bonds and having an acid anhydride group and / or a carboxyl group at the terminal (hereinafter referred to as “(A ³ -1) compound”) is synthesized.

The blending ratio when reacting the (raw material c) polyisocyanate with the (raw material a) trivalent and / or tetravalent polycarboxylic acid derivative having an acid anhydride group is the ratio of the compound (A ³ -1) to be produced. The number average molecular weight is appropriately adjusted depending on how much the molecular weight is made. However, since the terminal of the generated (A ³ -1) compound is an acid anhydride group and / or a carboxyl group, the total number of the acid anhydride group and the number of carboxyl groups in (raw material a)> (raw material c) the number of isocyanate groups. Here, the number of carboxyl groups includes R ³ and R ⁴ as hydrogen atoms, such as —COOR ³ in the compound represented by formula (3) and —COOR ^{4 in} the compound represented by formula (4). Also includes the number of certain carboxyl groups.

Note that (raw material a) and (raw material c) used in the synthesis method of (Method 3) are the same as (raw material a) and (raw material c) used in the synthesis method of (Method 1), respectively. used.
When synthesizing a compound having an acid anhydride group and / or carboxyl group at the terminal (A ³ -1), the ratio of the total number of acid anhydride groups and the number of carboxyl groups to the number of isocyanate groups (acid anhydride) The total number of the groups and the number of carboxyl groups / isocyanato group number) is preferably adjusted to 1.01 or more, and more preferably to 2.0 or less.

The number average molecular weight of the (A ³ -1) compound having an acid anhydride group and / or a carboxyl group at the terminal is preferably 500 to 15,000, more preferably 800 to 10,000, and 1,000 to 5,000. It is particularly preferred.

Next, the (A ³ -1) compound having an acid anhydride group and / or carboxyl group at the terminal is reacted with the polyol represented by (raw material b) formula (2) to form an amide bond and / or an imide bond. To produce a compound having: The ratio of the total number of acid anhydride groups in A ³ -1 to the number of hydroxyl groups in the raw material b is not particularly limited, but should be in the range of 0.9: 1.0 to 1.1: 1.0. Is more preferable, and the range of 0.95: 1.0 to 1.05: 1.0 is more preferable.

The (raw material b) used in the synthesis method of (Method 3) can be the same as the (raw material b) described in (Method 1).
From the viewpoint of improving chemical resistance and electrical properties, and controlling functional groups such as acid value, a method for obtaining a compound having an isocyanato group at the terminal in the first reaction (that is, (Method 1) and (Method 2)) Is preferred.

The reactions of (Method 1) to (Method 3) can be performed by heating them in the presence of an organic solvent, preferably a non-nitrogen-containing polar solvent.
Examples of the non-nitrogen-containing polar solvent include ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and triethylene glycol diethyl ether; sulfur-containing solvents such as dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, and sulfolane. An ester solvent such as γ-butyrolactone and cellosolve acetate; a ketone solvent such as cyclohexanone and methyl ethyl ketone; and an aromatic hydrocarbon solvent such as toluene and xylene. These can be used alone or in combination of two or more.

  Among the above solvents, it is preferable to select and use a solvent in which the resin to be generated can be dissolved. Moreover, it is preferable to use what is suitable as a solvent of a thermosetting composition as it is after a synthesis | combination. Among the above solvents, in order to perform the reaction in a homogeneous system efficiently, γ-butyrolactone and a mixed solvent containing γ-butyrolactone are preferable.

  In order to synthesize (Component A), the amount of solvent used is preferably 0.8 to 5.0 times (mass ratio) with respect to the total amount of (Component A). It is preferable that the amount used is 0.8 to 5.0 because the viscosity at the time of synthesis does not become too high and the reaction rate does not decrease.

  The reaction temperature is preferably 60 to 210 ° C, more preferably 70 to 190 ° C, and particularly preferably 80 to 180 ° C. If this temperature is less than 60 ° C, the reaction time tends to be too long, and if it exceeds 210 ° C, gelation tends to occur during the reaction. The reaction time can be appropriately selected depending on the capacity of the reaction vessel 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, cobalt, or a metalloid compound.
In the present specification, the number average molecular weight means a value measured by gel permeation chromatography (GPC) and converted using a standard polystyrene calibration curve.
The number average molecular weight, mass average molecular weight, and degree of dispersion are defined as follows.
(A) Number average molecular weight (Mn)
Mn = Σ (N _i M _i ) / ΣN _i = ΣX _i M _i
(X _i = Mole fraction of molecules with molecular weight M _i = N _i / ΣN _i )
(B) Mass average molecular weight (Mw)
Mw = Σ (N _i M _i ² ) / ΣN _i M _i = ΣW _i M _i
(W _i = mass fraction of molecules with molecular weight M _i = N _i M _i / ΣN _i M _i )
(C) Molecular weight distribution (dispersion degree)
Dispersity = Mw / Mn

Moreover, in this specification, unless otherwise indicated, the measurement conditions of GPC are as follows.
Device name: HPLC unit HSS-2000 manufactured by JASCO Corporation
Column: Shodex (registered trademark) 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 amount: 100 μl of sample loop Sample concentration: adjusted to around 0.1% by mass.

  The acid value of (Component A) is preferably 10 to 50 mgKOH / g. Furthermore, Preferably it is 10-35 mgKOH / g, Most preferably, it is 15-30 mgKOH / g. When the acid value of (Component A) is from 10 to 50 mgKOH / g, the warpage is not excessively large and the curing is sufficient, so that it is possible to suppress a decrease in weather resistance, flexibility, and the like.

In addition, the acid value of (Component A) can be measured by the following method. First, about 1 g of the solution containing (Component A) is precisely weighed. Thereafter, 30 g of a mixed solvent of isopropyl alcohol / toluene = 1/2 (mass ratio) is added thereto and dissolved uniformly. An appropriate amount of phenolphthalein as an indicator is added to the obtained solution, and titration is performed using a 0.1N KOH solution (alcoholic). And from the titration result, the following formula (α):
A = 10 × Vf × 56.1 / (Wp × I) Expression (α)
To calculate the acid value. In the formula (α), A represents the acid value (mgKOH / g), Vf represents the titration amount (mL) of the 0.1N KOH solution, and Wp represents the mass (g) of the solution containing (Component A). I represents the proportion (% by mass) of the nonvolatile content of the solution containing (Component A).

  The number average molecular weight of the component A thus obtained is preferably 5,000 to 50,000, more preferably 6,000 to 40,000, and particularly preferably 7,000 to 25,000. A number average molecular weight of 5,000 to 50,000 is preferable because it can suppress a decrease in weather resistance or chemical resistance and can maintain solubility in a non-nitrogen-containing polar solvent.

Next, (Component B) which is an essential component of the curable composition of the present invention will be described.
The curable composition which concerns on this embodiment further contains the hardening | curing agent which can harden the said (component A). The curing agent is a compound having two or more functional groups capable of reacting with the functional group of the component (A) in one molecule. When the component (A) has any of a carboxyl group, a hydroxyl group, an acid anhydride group, an isocyanato group, an amide group, and an amino group, the curing agent of the component (B) is an epoxy group or isocyanato that reacts with those functional groups. It preferably has a plurality of groups, hydroxyl groups and carboxyl groups.

  The epoxy group-containing compound used as a curing agent is one or more compounds having an epoxy group in one molecule, and at least one of them has two or more epoxy groups in one molecule. If included, there is no particular limitation.

  Specific examples of the epoxy group-containing compound used as the curing agent include phenol novolac type epoxy resins, orthocresol novolak type epoxy resins, phenol, cresol, xylenol, resorcin, catechol, phenols and / or α-naphthol. Epoxidized novolak resin obtained by condensation or cocondensation of naphthols such as β-naphthol and dihydroxynaphthalene with compounds having an aldehyde group such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde and salicylaldehyde in the presence of an acidic catalyst Diglycidy such as novolak epoxy resin, bisphenol A, bisphenol F, bisphenol S, alkyl-substituted or unsubstituted biphenol, stilbene phenols Luether (bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol S type epoxy compound, biphenyl type epoxy compound, stilbene type epoxy compound), glycidyl ether of alcohols such as butanediol, polyethylene glycol, polypropylene glycol, phthalic acid, Glycidyl ester type epoxy resin of carboxylic acids such as isophthalic acid and tetrahydrophthalic acid, glycidyl type such as those in which active hydrogen bonded to nitrogen atom such as aniline, bis (4-aminophenyl) methane, isocyanuric acid is substituted with glycidyl group Alternatively, methyl glycidyl type epoxy resin, active hydrogen bonded to nitrogen atom of aminophenols such as p-aminophenol, and active hydrogen of phenolic hydroxyl group are replaced with glycidyl group Glycidyl type or methyl glycidyl type epoxy resin, vinylcyclohexene diepoxide obtained by epoxidizing an olefin bond in the molecule, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 2- ( Of alicyclic epoxy resins such as 3,4-epoxy) cyclohexyl-5,5-spiro (3,4-epoxy) cyclohexane-m-dioxane, glycidyl ether of paraxylylene and / or metaxylylene modified phenolic resin, terpene modified phenolic resin Glycidyl ether, glycidyl ether of dicyclopentadiene modified phenolic resin, glycidyl ether of cyclopentadiene modified phenolic resin, glycidyl ether of polycyclic aromatic ring modified phenolic resin, naphthalene -Containing phenolic resin glycidyl ether, halogenated phenol novolak epoxy resin, hydroquinone epoxy resin, trimethylolpropane epoxy resin, linear aliphatic epoxy resin obtained by oxidizing olefinic bonds with peracid such as peracetic acid, diphenylmethane Type epoxy resin, phenol aralkyl resin, epoxidized aralkyl type phenol resin such as naphthol aralkyl resin, sulfur atom-containing epoxy resin, diglycidyl ether of tricyclo [5,2,1,02,6] decandimethanol, 1,3 -Bis (1-adamantyl) -4,6-bis (glycidylyl) benzene, 1- [2 ', 4'-bis (glycidylyl) phenyl] adamantane, 1,3-bis (4'-glycidylylphenyl) adamantane And 1,3-bis [2 ' 4'-bis (Gurishijiroiru) phenyl] adamantane structure such as adamantane and epoxy resins having. These can be used alone or in combination of two or more.

As the compound having two or more epoxy groups in one molecule, a compound having two or more epoxy groups in one molecule and having an aromatic ring structure and / or an alicyclic structure is preferable.
In the case where importance is attached to the long-term electrical insulation performance of the cured film of the present invention described later, among the compounds having two or more epoxy groups in one molecule and having an aromatic ring structure and / or an alicyclic structure, cyclopentadiene-modified phenolic resins of glycidyl ether (i.e., tricyclo [5,2,1,0 ^2,6] have decane structure and aromatic ring structure and a compound having two or more epoxy groups), 1,3-bis (1-adamantyl) -4,6-bis (glycidylyl) benzene, 1- [2 ′, 4′-bis (glycidylyl) phenyl] adamantane, 1,3-bis (4′-glycidylylphenyl) adamantane and 1 Epoxy resin having an adamantane structure such as 3,3-bis [2 ′, 4′-bis (glycidylyl) phenyl] adamantane (ie, tricyclo [3,3,1,1 ^3,7 ] decane A compound having a tricyclodecane structure and an aromatic ring structure and having two or more epoxy groups, such as a compound having a structure and an aromatic ring structure and having two or more epoxy groups). It is preferable because it can be provided, and a compound represented by the following formula (6) is particularly preferable.

（式（６）中のｍは正の整数を表す。）

(M in the formula (6) represents a positive integer.)

  On the other hand, when importance is attached to the reactivity with the aforementioned (Component A) of the present invention, among compounds having two or more epoxy groups in one molecule and having an aromatic ring structure and / or an alicyclic structure. , Glycidyl-type or methylglycidyl-type epoxy resins such as those in which active hydrogen bonded to the nitrogen atom of aniline or bis (4-aminophenyl) methane is substituted with a glycidyl group, nitrogen of aminophenols such as p-aminophenol An amino group and an aromatic ring structure such as an active hydrogen bonded to an atom and an active hydrogen of a phenolic hydroxyl group substituted with a glycidyl group or an epoxy resin of a methyl glycidyl type, and two or more epoxy groups The compound which has is preferable, Especially preferably, it is a compound as described in following formula (7).

  Examples of the compound having a plurality of isocyanato groups used as a curing agent, that is, a polyisocyanate compound, include diisocyanate compounds, triisocyanates, and other tetrafunctional or higher functional isocyanates. Considering the change over time when (Component A) and the curing agent are mixed, it is preferable to use a polyisocyanate compound in which an isocyanato group is stabilized with a blocking agent. These can be used alone or in combination of two or more.

  Examples of the blocking agent include alcohol, phenol and oxime, but there is no particular limitation. As this blocked isocyanate, for example, trade names “DURANATE 17B-60PX, TPA-B80E, MF-B60X, MF-K60X, E402-B80T” manufactured by Asahi Kasei Chemicals Corporation, trade names “Karenz MOI-BM, MOI-BP ", trade names" BL-3175, BL-4165, Desmo Cup 11, Desmo Cup-12 "manufactured by Sumika Bayer Urethane Co., Ltd. and the like. The blocked isocyanate is preferably selected in accordance with the thermosetting temperature of (Component A), and BL-3175 is particularly preferable during low temperature curing.

  The hydroxyl group-containing compound used as the curing agent is one or more compounds having a hydroxyl group in one molecule, and at least one of them has a compound having two or more hydroxyl groups in one molecule. There is no particular limitation.

  Examples of the hydroxyl group-containing compound used as the curing agent include polyhydric alcohols, and specific examples include ethylene glycol, glycerin, butanediol, pentaerythritol and the like.

  The carboxyl group-containing compound used as the curing agent is one or more compounds having a carboxyl group in one molecule, and at least one of them has a compound having two or more carboxyl groups in one molecule. If included, there is no particular limitation.

  Examples of the carboxyl group-containing compound used as the curing agent include polyvalent carboxylic acids, and specific examples include phthalic acid, succinic acid, trimellitic acid, adipic acid, pyromellitic acid and the like.

  As the curing agent, an epoxy group-containing compound, a polyisocyanate compound, a hydroxyl group-containing compound, and a carboxyl group-containing compound can be used alone or in combination, and can be selected according to the reactive group of (Component A). For example, when (Component A) has a hydroxy group, it is preferable to use a blocked isocyanate, and when (Component A) has a carboxyl group or an amino group, it is preferable to use an epoxy-containing compound. The curing agent is not limited to an epoxy group-containing compound, a polyisocyanate compound, a hydroxyl group-containing compound, and a carboxyl group-containing compound as long as it reacts with the reactive group of (Component A).

  The amount of (Component B) in the curable composition of the present invention is 1 to 55% by mass, preferably 2 to 45% by mass, based on the total amount of (Component A) and (Component B) in the curable composition. More preferably, it is 2.5-30 mass%. The amount of (Component B) in the curable composition of the present invention is 1 to 55% by mass based on the total mass of (Component A) and (Component B) in the curable composition. It is preferable from the viewpoint of the solvent resistance of the cured film, and the balance between the low warpage of the flexible wiring board characterized by being covered with the cured film, suitable electrical insulation reliability, and the effect of suppressing the wiring breakage. Can take.

  Moreover, the quantity of (component A) in the curable composition of this invention is 45-99 mass% with respect to the total amount of (component A) and (component B) in a curable composition, Preferably it is 55-98. It is mass%, More preferably, it is 70-97.5 mass%. The amount of (Component A) in the curable composition of the present invention is 45 to 99% by mass based on the total amount of (Component A) and (Component B) in the curable composition. It is preferable from the viewpoint of the solvent resistance of the cured film, and it is possible to balance the low warpage of the flexible wiring board characterized by being covered with the cured film and the effect of suppressing wiring breakage.

Next, (Component C) which is an essential component of the curable composition of the present invention will be described.
The organic solvent used as (Component C) is not particularly limited as long as it can dissolve (Component A) and (Component B). For example, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, Ether solvents such as diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, diethylene glycol isopropyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol dimethyl ether, ethylene glycol Monomethyl ether acetate, ethylene glycol monoe Ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, methyl methoxypropionate, methoxypropionic acid Ester solvents such as ethyl, methyl ethoxypropionate, ethyl ethoxypropionate and γ-butyrolactone, hydrocarbon solvents such as decahydronaphthalene, ketone solvents such as cyclohexanone, and aromatic hydrocarbon solvents such as toluene and xylene These solvents can be used alone or in combination of two or more. .

  Among these, γ-butyrolactone, diethylene glycol diethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate are preferable, and more preferably γ-butyrolactone, diethylene glycol, in consideration of the balance between screen printability and organic solvent volatility. Monoethyl ether acetate and diethylene glycol diethyl ether, most preferably a single solvent of γ-butyrolactone, a mixed solvent of two types of γ-butyrolactone and diethylene glycol monoethyl ether acetate, a mixed solvent of two types of γ-butyrolactone and diethylene glycol diethyl ether, And γ-butyrolactone, diethylene glycol monoethyl ether acetate and diethylene glycol A three mixed solvent of call diethyl ether.

These preferable combinations of solvents are suitable because they are excellent as solvents for screen printing inks.
Moreover, as a part of these preferable organic solvents, it is possible to use the solvent for synthesis in producing the above-mentioned (Component A) as it is as a part of the organic solvent of the curable composition of the present invention. Yes and process-preferred.

  The content of (Component C) in the curable composition of the present invention is (Component A), (Component B), (Component C), and (Component D) described later, which are components of the curable composition of the present invention. Of the total amount (however, when (Component D) is not included in the curable composition of the present invention, the total amount of (Component A), (Component B) and (Component C)) is preferably 25 to 25%. It is 75 mass%, More preferably, it is 35-65 mass%. The total amount of (Component A), (Component B), (Component C), and the filler described later, where the content of (Component C) is a component of the curable composition of the present invention (however, the curability of the present invention) When the composition does not contain a filler, the total amount of (Component A), (Component B) and (Component C)) is in the range of 25 to 75% by mass. Since the viscosity is good for printing by the screen printing method and the spread due to bleeding of the curable composition after screen printing does not increase so much, as a result, the portion to be coated with the curable composition (that is, the shape of the printing plate) ), The printing area of the actual curable composition does not become too large.

Moreover, in the said curable composition, it is preferable that (Component C) is contained in the quantity of 0.5-20 mass parts with respect to 100 mass parts (Component A).
In addition, the curable composition of the present invention can and preferably includes at least one kind of fine particles selected from the group consisting of inorganic fine particles and organic fine particles which are (Component D).

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 ), silicon nitride (Si ₃ N ₄ ). , Barium titanate (BaO · TiO ₂ ), barium carbonate (BaCO ₃ ), lead titanate (PbO · TiO ₂ ), lead zirconate titanate (PZT), zirconate titanate, lanthanum lead (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 (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) Hydrotalcite 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. These resins are preferably polyimide resins or precursors thereof, polyamideimide resins or precursors thereof, or polyamide resins from the viewpoint of heat resistance and mechanical properties. These can be used alone or in combination of two or more.
Among these, (Component D) can preferably include at least one selected from silica fine particles and hydrotalcite fine particles.

The silica fine particles used in the curable composition of the present invention are defined to include fine particles that are physically coated with a powder or chemically surface-treated with an organic compound.
The silica particles used in the curable composition of the present invention are not particularly limited as long as they are dispersed in the curable composition of the present invention to form a paste. For example, provided by Nippon Aerosil Co., Ltd. Aerosil etc. which can be mentioned.
Silica fine particles represented by these aerosils are sometimes used for imparting printability during screen printing, and in that case, they are used for the purpose of imparting thixotropy.

Further, hydrotalcite is a kind of naturally occurring clay minerals typified by Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O and is a layered inorganic compound. The hydrotalcite may be a synthetic material, and such a hydrotalcite is an Mg / Al-based layered compound, and chloride ions (Cl ⁻ ) and ion are exchanged with a carbonate group between layers. / Or Anion of sulfate ion (SO ⁴⁻ ) can be immobilized. Using this function, chloride ions (Cl ⁻ ) and sulfate ions (SO ⁴⁻ ), which cause migration of copper and tin, can be captured and used for the purpose of improving insulation reliability. .

Examples of commercially available hydrotalcite include STABIACE HT-1, STABIACE HT-7, STABIACE HT-P from Sakai Chemical Co., Ltd., DHT-4A, DHT-4A2, DHT-4C from Kyowa Chemical Industry Co., Ltd. Is mentioned.
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.

  Moreover, the compounding quantity of (component D) is 0.1-60 mass% with respect to the total amount of (component A), (component B), (component C), and (component D), Preferably 0.3- It is 55 mass%, More preferably, it is 0.5-40 mass%. When the compounding quantity of (Component D) exists in the range of 0.1-60 mass% with respect to the total amount of (Component A), (Component B), (Component C), and (Component D), curable composition Since the viscosity of the product is good for printing by the screen printing method and the spread due to bleeding of the curable composition after screen printing does not increase so much, as a result, the portion where the curable composition is to be applied (that is, the printing plate) The actual printed area of the curable composition does not become too large.

Moreover, in the said curable composition, it is preferable that (Component D) is contained in the quantity of 1-30 mass parts with respect to 100 mass parts (Component A).
In the curable composition of the present invention, as a method of dispersing organic and / or inorganic fine particles, roll kneading, mixer mixing and the like usually performed in the paint field are applied, and sufficient dispersion is performed. I just need it.

Furthermore, the curable composition of the present invention can and preferably includes an antifoaming agent for the purpose of eliminating or suppressing the generation of bubbles during printing.
Specific examples of the antifoaming agent used in the curable composition of the present invention include, for example, BYK-077 (manufactured by Big Chemie Japan), SN deformer 470 (manufactured by San Nopco), TSA750S (momentive performance Materials), silicone-based antifoaming agents such as silicone oil SH-203 (Toray Dow Corning), Dappo SN-348 (San Nopco), Dappo SN-354 (San Nopco), Acrylic polymer antifoaming agents such as Dappo SN-368 (manufactured by San Nopco), Disparon 230HF (manufactured by Enomoto Kasei Co., Ltd.), Surfynol DF-110D (manufactured by Nissin Chemical Industry Co., Ltd.), Surfynol DF-37 ( Acetylenediol antifoaming agent such as Nissin Chemical Industry Co., Ltd. And the like fluorine-containing silicone-based defoaming agents such as -630. These can be used alone or in combination of two or more.

  The content of the antifoaming agent is the total amount of (Component A), (Component B), (Component C) and (Component D) (provided that (Component D) is not included in the curable composition of the present invention). Is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 4 parts by weight, based on 100 parts by weight of (component A), (component B) and (component C). Yes, particularly preferably 0.1 to 3 parts by mass.

Moreover, in the said curable composition, it is preferable that the antifoamer is contained in the quantity of 0.2-10 mass parts with respect to 100 mass parts (component A).
Furthermore, the curable composition of the present invention can and preferably includes a curing accelerator. The curing accelerator is not particularly limited as long as it is a compound that accelerates the reaction between an epoxy group and a carboxyl group. -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 Compound, 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-methylimidazole, N- [2- (2-Methyl-1-imidazolyl) ethyl] urea, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-methylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium tri Melitrate, 1-cyanoethyl-2-ethyl-4-methylimidazolium trimellitate, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- ( 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-phenylimidazole Isocyanuric acid adduct, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine Luric 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, 2,3- Imidazole compounds such as dihydro-1H-pyrrolo [1,2-a] benzimidazole, 1-benzyl-2-phenylimidazole hydrobromide, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 1,5 -Diazabicyclo (4.3.0) -5 and salts thereof, cycloamidine compounds such as diazabicycloalkenes such as 1,8-diazabicyclo (5.4.0) undecene-7 and salts thereof, and derivatives of cycloamidine compounds, triethylenediamine, benzyldimethylamine, Amine compounds such as triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol, triphenylphosphine, diphenyl (p-tolyl) phosphine, tris (alkylphenyl) phosphine, tris (alkoxyphenyl) phosphine, tris (alkyl・ Alkoxyphenyl) phosphine, Tris (dialkylphenyl) phosphine, Tris (trialkylphenyl) phosphine, Tris (tetraalkylphenyl) phosphine, Tris (dialkoxyphenyl) ) Phosphine, tris (trialkoxyphenyl) phosphine, tris (tetraalkoxyphenyl) phosphine, trialkylphosphine, dialkylarylphosphine, alkyldiarylphosphine, and other phosphine compounds, dicyandiazide, and the 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 and electrical insulation performance, preferred are melamine, imidazole compounds, cycloamidine compounds, derivatives of cycloamidine compounds, phosphine compounds and amines. 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 viewpoint of the curability of the curable composition of the present invention and the electrical insulation properties and water resistance of the overcoat film obtained by curing the curable composition of the present invention, the curable composition of the present invention contains It is preferable to mix in the range of 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the total amount of (component A) and (component B) which are essential components of the present invention. Part. When the blending amount is in the range of 0.05 to 5 parts by mass with respect to 100 parts by mass of the total amount of (Component A) and (Component B), it can be cured in a short time and the curability of the present invention. The electrical insulation characteristics and water resistance of the overcoat film obtained by curing the composition are improved.

  Moreover, when it is necessary to suppress acid value deterioration of the resin and discoloration during heating, the curable composition of the present invention includes a phenolic antioxidant, a phosphite antioxidant, a thioether antioxidant, and the like. An antioxidant can be added.

  Furthermore, a leveling agent, a colorant such as a dye or a pigment, a flame retardant, and a lubricant are added to the curable composition of the present invention in order to improve workability during coating and film properties before and after film formation. You can also.

  The method for producing the curable composition of the present invention is not particularly limited as long as (Component A), (Component B) and (Component C) and, if necessary, other components can be dissolved or dispersed in an organic solvent. . For example, the curable composition of the present invention may be produced by producing a main agent containing at least (Component A) and a curing agent containing at least (Component B), and then blending the main agent and the curing agent. .

  In addition, the curable composition of the present invention improves the screen printability and prevents the composition from flowing and not having a constant film thickness after printing the curable composition. The thixotropy index is desirably 1.1 or more at 25 ° C., more preferably in the range of 1.1 to 3.0, and particularly preferably in the range of 1.1 to 2.5. In order for the thixotropy index to be 1.1 or more at 25 ° C., there are a method of adjusting the thixotropy index using the inorganic fine particles and organic fine particles, a method of adjusting the thixotropy index using a polymer additive, and the like. The method of adjusting the thixotropy index using inorganic fine particles or organic fine particles is preferred.

  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.

  The curable composition preferably has a viscosity at 25 ° C. of 20 Pa · s to 80 Pa · s, more preferably 30 Pa · s to 50 Pa · s, as measured by a rotary viscometer. When the viscosity is less than 20 Pa · s, there is a tendency that the flow of the composition after printing becomes large and the film thickness tends to be reduced, and when it exceeds 80 Pa · s, the transfer property of the composition to the substrate is increased. There is a tendency that voids and pinholes in the printed film increase with decreasing.

Finally, the cured film of the present invention, the overcoat film of the present invention, the flexible wiring board, and the method for producing the flexible wiring board will be described.
The cured film of the present invention includes a cured product that can be obtained by curing the curable composition of the present invention. Moreover, the electronic component of this invention has the said cured film.

  The overcoat film of the present invention is an overcoat film for a flexible wiring board containing a cured product of the curable composition of the present invention. More specifically, the curable composition of the present invention is wired on a flexible substrate. This is an overcoat film for a flexible wiring board obtained by applying and curing a part or all of the surface on which the wiring is formed of the formed flexible wiring board.

  Moreover, the flexible wiring board of the present invention is a flexible wiring board in which a part or all of the surface on which the wiring is formed of the flexible wiring board formed by wiring on the flexible substrate is covered with the overcoat film. is there.

Note that the wiring covered with the overcoat film is preferably a tin-plated copper wiring in view of the oxidation prevention and economical aspect of the wiring.
Furthermore, the manufacturing method of the flexible wiring board of this invention is a manufacturing method of the flexible wiring board coat | covered with the overcoat film | membrane including the following process 1 'and process 2'.

(Step 1 ′) Step of forming a printed film on the pattern by printing the curable composition of the present invention on at least a part of the wiring pattern portion of the flexible wiring board (Step 2 ′) Obtained in Step 1 ′ The printed film obtained, the printed film obtained in step 1 ′ is placed in an atmosphere of 40 to 100 ° C. to remove a part of the solvent in the printed film, or the printed film from which a part of the solvent is removed, or The printing film obtained in step 1 ′ is placed in an atmosphere of 40 to 100 ° C. to evaporate all the solvent in the printing film, and the printing film from which the entire amount of solvent has been removed is heated at 100 to 170 ° C. The process of making it harden | cure and forming an overcoat film | membrane.

  The curable composition of the present invention can be used, for example, as an ink for an overcoat film for insulation protection of wiring, and the cured product of the present invention can be used as an overcoat film for insulation protection. In particular, for example, by covering all or part of the wiring of a flexible wiring board such as a chip-on-film (COF), it can be used as an overcoat film for insulating and protecting the wiring.

  Below, the specific process performed with the manufacturing method of the flexible wiring board of this invention is described. For example, the overcoat film of the flexible wiring board can be formed through the following step 1 and step 3 and step 2 as necessary.

(Process 1)
The process of forming a printed film on this pattern by printing the curable composition of this invention in at least one part of the wiring pattern part of a flexible wiring board (process 2)
A step of evaporating a part or all of the solvent in the printed film by placing the printed film obtained in step 1 in an atmosphere of 40 to 100 ° C. (step 3)
A step of curing the printed film obtained in step 1 or the printed film obtained in step 2 at 100 to 170 ° C. to form an overcoat film.

  The temperature at which the solvent in the printed film is evaporated by placing the printed film obtained in Step 1 in an atmosphere of 40 to 100 ° C., which is carried out in Step 2, depends on the evaporation rate of the solvent and the subsequent operation (100 to 100). In consideration of a rapid transition to an operation of curing by heating at 170 ° C., it is usually 40 to 100 ° C., preferably 60 to 100 ° C., and more preferably 70 to 90 ° C. The time for evaporating the solvent in the printed film by placing the printed film obtained in Step 1 in an atmosphere of 40 to 100 ° C. carried out in Step 2 is not particularly limited, but preferably 10 to 120. Minutes, more preferably 20 to 100 minutes.

  The operation of evaporating the solvent in the printed film by placing the printed film obtained in Step 1 in an atmosphere of 40 to 100 ° C. is an operation performed as necessary. Immediately, the process may be shifted to Step 3 and heated at 100 to 170 ° C. to cure and form an overcoat film, and the curing reaction and the solvent removal may be performed together. The thermosetting conditions performed here are preferably 105 to 160 ° C., more preferably 110 from the viewpoint of preventing the diffusion of the plating layer and obtaining low warpage and flexibility suitable as a protective film. ~ 150 ° C. There is no particular limitation on the heat curing time when the film is cured by heating to form an overcoat film, but it is preferably 10 to 150 minutes, more preferably 15 to 120 minutes.

  By the method as described above, a flexible wiring board in which wiring is formed on a flexible substrate, a flexible wiring board in which a part or all of the surface on which the wiring is formed is covered with the overcoat film can be obtained. it can.

  In addition, the curable composition of the present invention is blended with the above-described optional components as necessary, and is uniformly mixed, and as a film forming material, an overcoat ink for semiconductor elements and various electronic components, solder resist ink, interlayer insulation Besides being useful as a film, it can also be used as a paint, a coating agent, an adhesive and the like.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples.
<Measurement of acid value>
The acid value of the solution containing (Component A) used in the present invention was measured by the following method, and the acid value of (Component A) was determined using the formula (α). However, the solvent used in the solution is one having an acid value of “0”.

First, about 1 g of the solution containing (Component A) is precisely weighed. Thereafter, 30 g of a mixed solvent of isopropyl alcohol / toluene = 1/2 (mass ratio) is added thereto and dissolved uniformly. An appropriate amount of phenolphthalein as an indicator is added to the obtained solution, and titration is performed using a 0.1N KOH solution (alcoholic). And from the titration result, the following formula (α):
A = 10 × Vf × 56.1 / (Wp × I) Expression (α)
To calculate the acid value. In the formula (α), A represents the acid value (mgKOH / g), Vf represents the titration amount (mL) of the 0.1N KOH solution, and Wp represents the mass (g) of the solution containing (Component A). I represents the ratio (mass%) of the component (A) of the solution containing (component A).

<Measurement of hydroxyl value>
The hydroxyl value was measured according to JIS K0070.
<Measurement of number average molecular weight>
The number average molecular weight is a polystyrene-reduced number average molecular weight measured by GPC, and GPC measurement conditions are as follows.
Device name: HPLC unit HSS-2000 manufactured by JASCO Corporation
Column: Shodex (registered trademark) 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 amount: 100 μl of sample loop Sample concentration: adjusted to around 0.1% by mass.

<Measurement of thixotropy index>
The thixotropy index of the curable composition was measured by the following method.
Using about 0.8 g of the curable composition, a cone / plate viscometer (Brookfield model: DV-II + Pro spindle model number: CPE-52) was used at a temperature of 25.0 ° C. and a rotation speed of 10 rpm. Under the conditions, the viscosity after 7 minutes from the start of measurement 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 obtained by the following calculation.
How to find the thixotropy index:
Thixotropic index = [viscosity at 1 rpm] ÷ [viscosity at 10 rpm]

<Synthesis of polyester polyol>
(Reference Synthesis Example 1) <Polyesterdiol (α)>
To a reaction vessel equipped with a stirrer, a thermometer and a condenser with a distillation device, 983.5 g (6.74 mol) of phthalic anhydride and 879.2 g (7.44 mol) of 1,6-hexanediol were added, and the reaction vessel The internal temperature was raised to 140 ° C. using an oil bath, and stirring was continued for 4 hours. Thereafter, while continuing stirring, 1.74 g of mono-n-butyltin oxide was added, the temperature inside the reaction vessel was gradually raised, a vacuum pump was connected, and the pressure inside the reaction vessel was gradually added. The pressure was reduced and water was removed by distillation under reduced pressure outside the reaction vessel. Finally, the internal temperature was raised to 220 ° C., and the pressure was reduced to 133.32 Pa. After 15 hours, it was confirmed that water was not completely distilled off, and the reaction was completed. The obtained polyester polyol (hereinafter referred to as polyester diol (α)) had the structure of the above formula (2), and n = 1 to 20. When the hydroxyl value was measured, the hydroxyl value was 53.1 mg-KOH / g.

<Synthesis of (Component A)>
(Synthesis example 1) <А-1 solution>
As a tetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA) 270. was added to a four-necked flask equipped with a stirrer, a condenser, a nitrogen inlet tube and a thermometer. 7 parts by mass and 964.4 parts by mass of γ-butyrolactone as a solvent were added and stirred and dissolved at 120 ° C. Thereto, 142.6 parts by mass of 4,4′-diphenylmethane diisocyanate (MDI) as a diisocyanate compound was added and stirred, and 1,8-diazabicyclo [5.4.0] -7-undecene (DBU) was used as a catalyst here. 0.1 part by mass was added and reacted at 120 ° C. for 3 hours under a nitrogen stream. Then, the terminal acid anhydride group containing imide prepolymer with a solid content concentration of 30 mass% was obtained by cooling to room temperature.

  Subsequently, the terminal acid anhydride group-containing imide prepolymer having a solid content concentration of 30% by mass was heated to 100 ° C. and stirred to obtain 908.7 parts by mass of polyester diol (α) and 1018.7 parts by mass of γ-butyrolactone. Was added and stirred. Here, 2.4 parts by mass of 4-dimethylaminopyridine (DMAP) was added as a catalyst and reacted at 100 ° C. for 8 hours. Then, the solution of the compound (henceforth "compound (A-1)") which has an imide bond and a hydroxyl group of 40 mass% of solid content concentration was obtained by cooling to room temperature. The number average molecular weight of the compound (A-1) was 15000, the degree of dispersion was 4.0, and the acid value of the solid content was 25 mgKOH / g.

(Synthesis Example 2) <А-2 solution>
As a tetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA) 270. was added to a four-necked flask equipped with a stirrer, a condenser, a nitrogen inlet tube and a thermometer. 7 parts by mass and 964.4 parts by mass of γ-butyrolactone as a solvent were added and stirred and dissolved at 120 ° C. Thereto, 142.6 parts by mass of 4,4′-diphenylmethane diisocyanate (MDI) as a diisocyanate compound was added and stirred, and 1,8-diazabicyclo [5.4.0] -7-undecene (DBU) was used as a catalyst here. 0.1 part by mass was added and reacted at 120 ° C. for 3 hours under a nitrogen stream. Then, the terminal acid anhydride group containing imide prepolymer with a solid content concentration of 30 mass% was obtained by cooling to room temperature.

Subsequently, the terminal acid anhydride group-containing imide prepolymer having a solid content concentration of 30% by mass was heated to 100 ° C. and stirred, and a polyester polyol of 3-methyl-1,5-pentanediol: isophthalic acid (manufactured by Kuraray Co., Ltd.). Product name: 908.7 parts by mass of Kuraray polyol P-2030 (*) and 1018.7 parts by mass of γ-butyrolactone were added and stirred. Here, 2.4 parts by mass of 4-dimethylaminopyridine (DMAP) was added as a catalyst and reacted at 100 ° C. for 8 hours. Then, the solution of the compound (henceforth "compound (A-2)") which has an imide bond and a hydroxyl group of solid content concentration 40 mass% was obtained by cooling to room temperature. The number average molecular weight of the compound (A-2) was 15000, the degree of dispersion was 4.0, and the acid value of the solid content was 25 mgKOH / g.
(* Polyester polyol having the structure of the above formula (2), the average of n is 8.0 to 8.1)

Synthesis Example 3 <А-3 Solution>
As a tetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA) 270. was added to a four-necked flask equipped with a stirrer, a condenser, a nitrogen inlet tube and a thermometer. 7 parts by mass and 863.2 parts by mass of γ-butyrolactone as a solvent were added and stirred and dissolved at 120 ° C. Then, as a diisocyanate compound, Cosmonate T-80 (Mitsui Chemical Polyurethane Co., Ltd.) (TDI) which is a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate in a mass ratio of 80:20. 3 parts by mass was added and stirred, and 0.1 part by mass of 1,8-diazabicyclo [5.4.0] -7-undecene (DBU) was added as a catalyst, and the mixture was stirred at 120 ° C. for 3 hours under a nitrogen stream. Reacted. Then, the terminal acid anhydride group containing imide prepolymer with a solid content concentration of 30 mass% was obtained by cooling to room temperature.

  Subsequently, the terminal acid anhydride group-containing imide prepolymer having a solid content concentration of 30% by mass was heated to 100 ° C. and stirred to obtain 908.7 parts by mass of polyester diol (α) and 1054.8 parts by mass of γ-butyrolactone. Was added and stirred. Here, 2.4 parts by mass of 4-dimethylaminopyridine (DMAP) was added as a catalyst and reacted at 100 ° C. for 8 hours. Then, the solution of the compound (henceforth "compound (A-3)") which has an imide bond and a hydroxyl group of 40 mass% of solid content concentration was obtained by cooling to room temperature. The number average molecular weight of the compound (A-3) was 15000, the degree of dispersion was 4.0, and the acid value of the solid content was 26 mgKOH / g.

(Synthesis Example 4) <А-4 solution>
As a tetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA) 270. was added to a four-necked flask equipped with a stirrer, a condenser, a nitrogen inlet tube and a thermometer. 7 parts by mass and 863.2 parts by mass of γ-butyrolactone as a solvent were added and stirred and dissolved at 120 ° C. Then, as a diisocyanate compound, Cosmonate T-80 (Mitsui Chemical Polyurethane Co., Ltd.) (TDI) which is a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate in a mass ratio of 80:20. 3 parts by mass was added and stirred, and 0.1 part by mass of 1,8-diazabicyclo [5.4.0] -7-undecene (DBU) was added as a catalyst, and the mixture was stirred at 120 ° C. for 3 hours under a nitrogen stream. Reacted. Then, the terminal acid anhydride group containing imide prepolymer with a solid content concentration of 30 mass% was obtained by cooling to room temperature.

  Subsequently, the terminal acid anhydride group-containing imide prepolymer having a solid content concentration of 30% by mass was heated to 100 ° C. and stirred, and a polyester polyol of 3-methyl-1,5-pentanediol: isophthalic acid (manufactured by Kuraray Co., Ltd.). (Product name: Kuraray polyol P-2030) 908.7 parts by mass and γ-butyrolactone 1054.8 parts by mass were added and stirred. Here, 2.4 parts by mass of 4-dimethylaminopyridine (DMAP) was added as a catalyst and reacted at 100 ° C. for 8 hours. Then, the solution of the compound (henceforth "compound (A-4)") which has an imide bond and a hydroxyl group of 40 mass% of solid content concentration was obtained by cooling to room temperature. The number average molecular weight of the compound (A-4) was 15000, the degree of dispersion was 4.0, and the acid value of the solid content was 26 mgKOH / g.

(Synthesis Example 5) <А-5 solution>
378.29 g (0.179 mol) of polyester diol (α) was placed in a reaction vessel equipped with a stirrer, a thermometer, and a condenser, and MILIONATE MT (produced by Nippon Polyurethane Industry Co., Ltd.) 53, which is 4,4′-diphenylmethane diisocyanate 53 Cosmonate T-80 (Mitsui Chemical Polyurethane Co., Ltd.) 24, which is a mixture of .65 g (0.214 mol) and a mass ratio of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate of 80:20 .89 g (0.143 mol) and γ-butyrolactone 685.3 g were charged, and all raw materials were dissolved at 150 ° C. and reacted for 4 hours to produce a polyisocyanate having a urethane bond.

  Next, the temperature of the reaction solution was lowered to 60 ° C., and 63.71 g (0.332 mol) of trimellitic anhydride was added and completely dissolved, and then 23.00 g (0.092 mol) of MILLIONATE MT and Cosmonate T-80 were added. Was added with 10.67 g (0.061 mol) and 146.07 g of γ-butyrolactone, and the mixture was heated to 120 ° C. to dissolve all the raw materials and reacted for 1 hour.

Thereafter, the temperature of the reaction solution was raised to 180 ° C. and reacted at 180 ° C. for 2 hours. Subsequently, the temperature of the reaction solution is lowered to 120 ° C., 5.61 g of 2-butanone oxime (manufactured by Wako Pure Chemical Industries, Ltd.) is added, the reaction is terminated, and the mixture is cooled to room temperature, whereby an amide having a solid content concentration of 40 mass% A solution of a compound having a bond and an imide bond and a block isocyanato group (hereinafter referred to as “compound (A-5)”) was obtained.
The number average molecular weight of the obtained compound (A-5) was 10,500, the degree of dispersion was 3.1, and the acid value of the solid content was 19 mgKOH / g.

(Synthesis Example 6) <А-6 solution>
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, 378.29 g (0.179 mol) of 3-methyl-1,5-pentanediol: polyester polyol of isophthalic acid (trade name: Kuraray Polyol P-2030 manufactured by Kuraray Co., Ltd.) 4,4′-diphenylmethane diisocyanate MILLIONATE MT (manufactured by Nippon Polyurethane Industry Co., Ltd.) 53.65 g (0.214 mol), and 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate Cosmonate T-80 (Mitsui Chemical Polyurethane Co., Ltd.) 24.89 g (0.143 mol) and γ-butyrolactone 685.3 g, which is a mixture with a mass ratio of 80:20, are charged and all raw materials are dissolved at 150 ° C. And react for 4 hours to obtain a urethane bond. To produce a isocyanate.

  Next, the temperature of the reaction solution was lowered to 60 ° C., and 63.71 g (0.332 mol) of trimellitic anhydride was added and completely dissolved, and then 23.00 g (0.092 mol) of MILLIONATE MT and Cosmonate T-80 were added. Was added with 10.67 g (0.061 mol) and 146.07 g of γ-butyrolactone, and the mixture was heated to 120 ° C. to dissolve all the raw materials and reacted for 1 hour.

Thereafter, the temperature of the reaction solution was raised to 180 ° C. and reacted at 180 ° C. for 2 hours. Subsequently, the temperature of the reaction solution is lowered to 120 ° C., 5.61 g of 2-butanone oxime (manufactured by Wako Pure Chemical Industries, Ltd.) is added, the reaction is terminated, and the mixture is cooled to room temperature, whereby an amide having a solid content concentration of 40 mass% A solution of a compound having a bond and an imide bond and a block isocyanato group (hereinafter referred to as “compound (A-6)”) was obtained.
The number average molecular weight of the obtained compound (A-6) was 10,500, the degree of dispersion was 3.1, and the acid value of the solid content was 19 mgKOH / g.

(Synthesis Example 7) <А-7 solution>
In a reaction vessel equipped with a stirrer, a thermometer and a condenser, 369.85 g (0.175 mol) of polyester diol (α) and Desmodur-W (Sumika Bayer Urethane Co., Ltd.) which is 4,4′-dicyclohexylmethane diisocyanate Product) 91.70 g (0.350 mol) and 692.33 g of γ-butyrolactone (Mitsubishi Chemical Corporation) as a solvent are charged, all raw materials are dissolved at 150 ° C. and reacted for 4 hours to form a urethane bond. A polyisocyanate having was produced.

  Subsequently, the temperature of the reaction solution was lowered to 80 ° C., and Desmodur-W was 45.85 g (0.175 mol), trimellitic anhydride (manufactured by Mitsubishi Gas Chemical Co., Inc.) 33.60 g (0.175 mol), and γ -Butyrolactone (Mitsubishi Chemical Co., Ltd.) 119.18g was added, it heated up at 150 degreeC, all the raw materials were dissolved, and it was made to react for 3 hours.

The temperature of the reaction solution is lowered to 80 ° C., 16.40 g (0.158 mol) of neopentyl glycol (manufactured by Kanto Chemical Co., Ltd.) as a diol is added, and the temperature is raised to 120 ° C. to dissolve all the raw materials for 4 hours. Reacted. Thereafter, the temperature of the reaction solution is lowered to 80 ° C., and 9.67 g (0.105 mol) of glycerin (manufactured by Kanto Chemical Co., Ltd.) as a triol and 39.10 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) are added. The temperature was raised to 0 ° C. and the reaction was allowed to proceed. The reaction is carried out while confirming the presence of the isocyanate group in the reaction solution by IR measurement. When the isocyanate group is no longer confirmed in the system, the reaction is terminated, and the reaction mixture is cooled to room temperature. A solution of a compound having an amide bond, an imide bond and a hydroxyl group (hereinafter referred to as “compound (A-7)”) was obtained.
The number average molecular weight of the obtained compound (A-7) was 10,000, the degree of dispersion was 4.3, the acid value of the solid content was 17 mgKOH / g, and the hydroxyl value was 10 mgKOH / g.

(Comparative Synthesis Example 1) <CА-1 solution>
As a tetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA) 270. was added to a four-necked flask equipped with a stirrer, a condenser, a nitrogen inlet tube and a thermometer. 7 parts by mass and 863.2 parts by mass of γ-butyrolactone as a solvent were added and stirred and dissolved at 120 ° C. Thereto, 99.27 parts by mass of Cosmonate T-80 (Mitsui Chemical Polyurethane Co., Ltd.), which is a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate in a mass ratio of 80:20 as a diisocyanate compound. Then, 0.1 part by mass of 1,8-diazabicyclo [5.4.0] -7-undecene (DBU) was added as a catalyst, and the mixture was reacted at 120 ° C. for 3 hours under a nitrogen stream. . Then, the terminal acid anhydride group containing imide prepolymer with a solid content concentration of 30 mass% was obtained by cooling to room temperature.

  Subsequently, the terminal acid anhydride group-containing imide prepolymer having a solid content concentration of 30% by mass was heated and stirred to 100 ° C., and as a polyol compound, a polycarbonate diol compound (trade name: DURANOL T5650E: manufactured by Asahi Kasei Chemicals Corporation) , Mn = 500) 100.0 parts by mass, and polyester diol of adipic acid / neopentyl glycol / 1,6-hexanediol (trade name: OD-X-688 manufactured by DIC Corporation, number average molecular weight of about 2,000) ) 460.0 parts by mass and 531.71 parts by mass of γ-butyrolactone were added and stirred. Here, 2.4 parts by mass of 4-dimethylaminopyridine (DMAP) was added as a catalyst and reacted at 100 ° C. for 8 hours. Then, the solution of the compound (henceforth "compound (CA-1)") which has an imide bond of 40 mass% of solid content concentration, a carboxyl group, and a hydroxyl group was obtained by cooling to room temperature. The number average molecular weight of the compound (CA-1) was 13,500, the degree of dispersion was 4.0, and the acid value of the solid content was 36 mgKOH / g.

(Comparative Synthesis Example 2) <CА-2 solution>
A reaction vessel equipped with a stirrer, a thermometer, and a condenser contains a structural unit derived from 1,4-cyclohexanedimethanol and a structural unit derived from 1,6-hexasandiol at a molar ratio of 1: 1. Polycarbonate diol UM-CARB90 (1/1) (manufactured by Ube Industries Co., Ltd.) 161.44 g (0.179 mol) is added, and MILLOIONATE MT (manufactured by Nippon Polyurethane Industry Co., Ltd.), which is 4,4′-diphenylmethane diisocyanate 53. Cosmonate T-80 (Mitsui Chemical Polyurethane Co., Ltd.), which is a mixture of 65 g (0.214 mol) and a mass ratio of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate of 80:20. 89 g (0.143 mol) and γ-butyrolactone 159.93 g were prepared. All raw materials were dissolved at 150 ° C. and reacted for 4 hours to produce a polyisocyanate having a urethane bond.

  Next, the temperature of the reaction solution was lowered to 60 ° C., and 63.71 g (0.332 mol) of trimellitic anhydride was added and completely dissolved, and then 23.00 g (0.092 mol) of MILLIONATE MT and Cosmonate T-80 were added. And 10.67 g (0.061 mol) of γ-butyrolactone and 342.98 g of γ-butyrolactone were added, the temperature was raised to 120 ° C., and all the raw materials were dissolved and reacted for 1 hour.

Thereafter, the temperature of the reaction solution was raised to 180 ° C. and reacted at 180 ° C. for 2 hours. Subsequently, the temperature of the reaction solution was lowered to 120 ° C., 3.13 g of 2-butanone oxime (manufactured by Wako Pure Chemical Industries, Ltd.) was added, the reaction was terminated, and the amide having a solid content concentration of 40% by mass was cooled to room temperature. A solution of a compound having a bond, an imide bond and a carboxyl group (hereinafter referred to as “compound (CА-2)”) was obtained.
The number average molecular weight of the obtained compound (CА-2) was 9200, the degree of dispersion was 3.1, and the acid value of the solid content was 31 mgKOH / g.

(Comparative Synthesis Example 3) <CА-3 solution>
A reaction vessel equipped with a stirrer, a thermometer, and a condenser contains a structural unit derived from 1,4-cyclohexanedimethanol and a structural unit derived from 1,6-hexasandiol in a molar ratio of 3: 1. Polycarbonate diol UM-CARB90 (3/1) (manufactured by Ube Industries, average molecular weight: about 900) 156.98 g (0.175 mol) and Desmodur-W (Sumi), which is 4,4′-dicyclohexylmethane diisocyanate Kay Bayer Urethane Co., Ltd.) 91.70 g (0.350 mol) and γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) 165.80 g as a solvent are charged and all raw materials are dissolved at 150 ° C. for 4 hours. Thus, a polyisocyanate having a urethane bond was produced.

  Subsequently, the temperature of the reaction solution was lowered to 80 ° C., and Desmodur-W was 45.85 g (0.175 mol), trimellitic anhydride (manufactured by Mitsubishi Gas Chemical Co., Inc.) 33.60 g (0.175 mol), and γ -Butyrolactone (Mitsubishi Chemical Co., Ltd.) 162.33g was added, and it heated up at 150 degreeC, dissolved all the raw materials, and made it react for 3 hours.

  The temperature of the reaction solution is lowered to 80 ° C., 16.40 g (0.158 mol) of neopentyl glycol (manufactured by Kanto Chemical Co., Ltd.) as a diol is added, and the temperature is raised to 120 ° C. to dissolve all the raw materials for 4 hours. Reacted. Thereafter, the temperature of the reaction solution is lowered to 80 ° C., 9.67 g (0.105 mol) of glycerin (manufactured by Kanto Chemical Co., Ltd.) as a triol and 26.07 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) are added. The reaction was allowed to proceed to a temperature of 0 ° C. The reaction is carried out while confirming the presence of the isocyanate group in the reaction solution by IR measurement. When the isocyanate group is no longer confirmed in the system, the reaction is terminated, and 177.1 g of γ-butyrolactone is added to obtain a solid concentration of 40 A solution of a compound having a mass% hydroxyl group, amide bond, imide bond and hydroxyl group (hereinafter referred to as “compound (CA-3)”) was obtained. The number average molecular weight of the obtained compound (CA-3) was 8000, the degree of dispersion was 4.4, the acid value of the solid content was 27 mgKOH / g, and the hydroxyl value was 16 mgKOH / g.

<Manufacture of base compound>
(Main compound 1)
160.0 parts by mass of the solution of the compound (A-1), 6.3 parts by mass of silica powder (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil R-974), and melamine (manufactured by Nissan Chemical Industries, Ltd.) as a curing accelerator ) 0.72 parts by mass and 8.4 parts by mass of diethylene glycol diethyl ether were mixed, and a compound (A-1) was obtained using a three roll mill (manufactured by Inoue Seisakusho Co., Ltd., model: S-4 3/4 × 11). The silica powder and the curing accelerator were mixed. Thereafter, 2.0 parts by mass of an antifoaming agent (manufactured by Momentive Performance Materials, trade name: TSA750S) was added and mixed using a spatula. This blend was designated as a base blend C1.

(Main agent formulations 2-7 and comparative main agent formulations 1-3)
According to the same method as the main agent formulation 1, the components were blended according to the blending composition shown in Table 1. The main agent formulations were 2 to 7, and the comparative main agent formulation ratios were 1 to 3, respectively.
In addition, the numerical value in a table | surface represents a "mass part."

<Production of curing agent solution>
(Formulation example 1 of curing agent solution) <B-1 solution>
In a container equipped with a stirrer, a thermometer and a condenser, an epoxy resin having a structure of the following formula (7) (Mitsubishi Chemical Corporation, grade name: JER604, epoxy equivalent 120 g / eqv) 16.85 parts by mass, diethylene glycol diethyl ether 18.25 parts by weight are added,
Agitation was started.

  While continuing stirring, the temperature in the container was raised to 40 ° C. using an oil bath. After raising the internal temperature to 40 ° C., stirring was continued for 30 minutes. Then, after confirming that JER604 was melt | dissolved completely, it cooled to room temperature and acquired the JER604 containing solution with a density | concentration of 48 mass%. This solution is designated as a curing agent solution B-1.

(Example 2 of curing agent solution) <B-2 solution>
An epoxy resin mainly composed of N, N-diglycidyl-4- (glycidyloxy) aniline (manufactured by Mitsubishi Chemical Corporation, grade name: JER630, epoxy equivalent 98 g / eqv) in a container equipped with a stirrer, a thermometer and a condenser. ) 16.85 parts by mass and 18.25 parts by mass of diethylene glycol diethyl ether were added and stirring was started.

  While continuing stirring, the temperature in the container was raised to 40 ° C. using an oil bath. After raising the internal temperature to 40 ° C., stirring was continued for 30 minutes. Then, it confirmed that JER630 was melt | dissolving completely, it cooled to room temperature, and the JER630 containing solution with a density | concentration of 48 mass% was acquired. This solution is designated as a curing agent solution B-2.

<Mixing of the solution containing the main compound blend and curing agent>
(Example 1 of curable composition)
88.71 parts by mass of the main compound formulation C1 and 3.51 parts by mass of the curing agent solution B-1 were placed in a plastic container. Further, 3.0 parts by mass of diethylene glycol diethyl ether and 1.5 parts by mass of diethylene glycol ethyl ether acetate were added as solvents in order to match the viscosity with the curable compositions of other formulation examples and comparative formulation examples described later. Mixing was performed by stirring for 5 minutes at room temperature using a spatula to obtain a curable composition (hereinafter referred to as “curable composition F1”).

(Examples 2-8 and Comparative Examples 1-3)
The curable composition was formulated according to the composition shown in Table 2 by the same method as in Example 1. The formulations prepared in Examples 2 to 8 of the curable composition were respectively curable compositions F2 to F8, and the formulations prepared in Comparative Examples 1 to 3 of the curable composition were respectively curable compositions G1 to G1. G3. Here, in the curable compositions F8 and G3, a block isocyanate “7950” manufactured by Baxenden corresponding to (Component B) was further blended.

In addition, the numerical value in a table | surface represents a "mass part."
In addition, Table 2 shows the composition of the curable compositions F1 to F8 and the curable compositions G1 to G3. Moreover, what put together the mass part for every component of the said curable composition F1-F8 and the curable composition G1-G3 is described in Table 3. Moreover, the number of epoxy groups / the number of carboxyl groups in Tables 2 and 3 was calculated from the acid value.

(Examples 1-8 and Comparative Examples 1-3)
Using the curable compositions F1 to F8 and the curable compositions G1 to G3, evaluation of flexibility, wire breakage suppression, warpage and long-term electrical insulation reliability were performed by the methods described below. The results are shown in Table 4.

<Evaluation of flexibility>
A flexible copper-clad laminate (manufactured 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 F1 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 protective PET film on the backing 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 ± using a compressor. Compressed at 0.2 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 4.
Moreover, the same evaluation was performed using the curable compositions F2 to F8 and the curable compositions G1 to G3. The results are also shown in Table 4.

<Evaluation of wire breakage suppression of wiring board (MIT test)>
Substrate with a fine comb pattern described in JPCA-ET01, manufactured by etching a flexible copper-clad laminate (manufactured by Sumitomo Metal Mining Co., Ltd., grade name: Esperflex US, copper thickness: 8 μm, polyimide thickness: 38 μm) A thickness of 10 μm from the polyimide surface of the coating film is applied to the flexible wiring board (copper wiring width / inter-copper wiring width = 15 μm / 15 μm) with a curable composition F1 by screen printing. It applied so that it might become (after drying). The obtained coating film-formed wiring board was 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 to cure the coating film.
Using this test piece, it was carried out under the following test conditions in the manner described in JIS C-5016.

(Test conditions)
Testing machine: MIT Tester BE202 manufactured by Tester Sangyo Co., Ltd.
Bending speed: 10 times / min Load: 200g
Bending angle: ± 90 °
Radius of gripper tip: 0.5mm
The number of bendings was increased 10 times under the above test conditions, the presence or absence of cracks in the wiring was visually observed, and the number of bendings when a crack occurred was recorded. The results are shown in Table 3.
Moreover, the same evaluation was performed using the curable compositions F2 to F8 and the curable compositions G1 to G3. The results are also shown in Table 4.

<Evaluation of warpage>
The curable composition F1 was applied to a substrate by screen printing with a # 180 mesh polyester plate, and the substrate was placed in a hot air circulation dryer at 80 ° C. for 30 minutes. Then, the applied curable composition F1 was cured by placing the substrate in a 120 ° C. hot air circulation dryer for 60 minutes. As the substrate, a 25 μm-thick polyimide film [Kapton (registered trademark) 100EN, manufactured by Toray DuPont Co., Ltd.] was used.

  The cured coating film was cut with a circle cutter to a diameter of 50 mmφ together with the substrate. What is cut into a circle exhibits a deformation in which the vicinity of the center warps in a convex or concave shape. The one that has been cut with a circle cutter and has a cured film formed on the substrate is placed in a convex state after 1 hour, that is, with the cured film formed on the substrate so that the vicinity of the center is in contact with the horizontal plane. The maximum and minimum values of the warp height from the horizontal plane were measured, and the average value was obtained. The sign represents the direction of warping, and when left in a convex state, “+” indicates that the cured film is on the upper side of the copper substrate or polyimide film, and “−” indicates that the cured film is on the lower side. It was. And if curvature was less than +3.0 mm, it was set as the pass.

The results are shown in Table 4.
Moreover, the same evaluation was performed using the curable compositions F2 to F8 and the curable compositions G1 to G3. The results are also shown in Table 4.

<Evaluation of long-term electrical insulation reliability>
Substrate with a fine comb pattern described in JPCA-ET01, manufactured by etching a flexible copper-clad laminate (manufactured by Sumitomo Metal Mining Co., Ltd., grade name: Esperflex US, copper thickness: 8 μm, polyimide thickness: 38 μm) A flexible wiring board (copper wiring width / inter-copper wiring width = 15 μm / 15 μm) subjected to tin plating is coated with the curable composition F1 by a screen printing method to a thickness of 15 μm from the polyimide surface (dried). It was applied so that The applied curable composition F1 was cured by placing the flexible wiring board in a hot air circulation dryer at 80 ° C. for 30 minutes and then in a 120 ° C. hot air circulation dryer for 120 minutes.

Using this test piece, a bias voltage of 60 V was applied, and a constant temperature and humidity test under the conditions of a temperature of 120 ° C. and a humidity of 85% RH was performed using MIGRATION TESTER MODEL MIG-8600 (manufactured by IMV). Table 4 shows the resistance values of the substrate having the fine comb pattern shape at the initial start of the temperature and humidity test and at 100 hours, 250 hours, and 400 hours after the start.
Moreover, the same evaluation was performed using the curable compositions F2 to F8 and the curable compositions G1 to G3. The results are also shown in Table 4.

表４の結果より、本発明の硬化性組成物は、可撓性、断線抑制性および長期電気絶縁信頼性に優れており、該硬化物はフレキシブル配線板用の絶縁保護膜として有用である。

From the results of Table 4, the curable composition of the present invention is excellent in flexibility, wire breakage suppression and long-term electrical insulation reliability, and the cured product is useful as an insulating protective film for flexible wiring boards.

  The curable composition of this invention can be utilized suitably for the insulation protection of a flexible wiring board.

Claims (16)

(Component A) A compound having a structural unit represented by the following formula (1), having a bond of at least one of an imide bond and an amide bond, and having a functional group that reacts with a curing agent,
A curable composition comprising (Component B) a curing agent, and (Component C) an organic solvent.

(In Formula (1), R ¹ represents an organic residue derived from a diol having 3 to 36 carbon atoms each independently, and R ² represents a phenylene group or a phenylene group having a substituent each independently. Represents.)   The curable composition according to claim 1, wherein the functional group that reacts with the curing agent is at least one of a carboxyl group, a hydroxyl group, an acid anhydride group, an isocyanato group, an amide group, and an amino group. (Component A) is (raw material a) a trivalent and / or tetravalent polycarboxylic acid derivative having an acid anhydride group, (raw material b) a polyol represented by the following formula (2), and (raw material c) poly The curable composition according to claim 1, comprising a compound obtained by reacting with an isocyanate as an essential component.

(In the formula (2), (n + 1 ) number of R ¹ represents an organic residue derived independently from diols 3 to 36 carbon atoms, n number of R ² is a phenylene group or a substituted independently Represents a phenylene group having a group, and n represents an integer of 1 to 60.)   (Component A) has a urethane bond further, The curable composition in any one of Claims 1-3 characterized by the above-mentioned.   The curable composition according to any one of claims 1 to 4, wherein the acid value of (Component A) is 10 to 50 mgKOH / g.   (Component B) contains the compound which has a 2 or more epoxy group per molecule | numerator, The curable composition of any one of Claims 1-5 characterized by the above-mentioned.   (Component C) is at least one organic solvent selected from the group consisting of ether solvents, ester solvents, ketone solvents, and aromatic hydrocarbon solvents. The curable composition of any one of Claims. further,
(Component D) The curable composition according to any one of claims 1 to 7, comprising at least one fine particle selected from the group consisting of inorganic fine particles and organic fine particles.   The curing according to any one of claims 1 to 8, comprising 1 to 55 parts by mass of the component (B) when the total amount of the component (A) and the component (B) is 100 parts by mass. Sex composition.   Total amount of component (A), component (B), component (C), and component (D) (when component (D) is not included, component (A), component (B), and component (C) The curable composition according to any one of claims 1 to 9, comprising 25 to 75 parts by mass of the component (C) when the total amount is 100 parts by mass.   The cured film containing the hardened | cured material of the curable composition of any one of Claims 1-10.   The curable composition according to any one of claims 1 to 10 is applied to a part or all of a surface of a flexible wiring board in which wiring is formed on a flexible substrate and cured. The overcoat film for flexible wiring boards obtained by this.   A flexible wiring board having a wiring formed on a flexible substrate, wherein a part or all of the surface on which the wiring is formed is covered with the overcoat film according to claim 12. .   The flexible wiring board according to claim 13, wherein the wiring is tin-plated copper wiring. A process for producing a flexible wiring board covered with an overcoat film, comprising the following (Step 1) and (Step 3) and (Step 2) as necessary;
(Process 1)
The process of forming a printed film on this pattern by printing the curable composition of any one of Claims 1-10 on at least one part of the wiring pattern part of a flexible wiring board (process 2)
A step of evaporating a part or all of the solvent in the printed film by placing the printed film obtained in step 1 in an atmosphere of 40 to 100 ° C. (step 3)
A step of curing the printed film obtained in step 1 or the printed film obtained in step 2 at 100 to 170 ° C. to form an overcoat film.   An electronic component having the cured film according to claim 11.