JP2011105950A - Urethane resin, thermosetting resin composition containing the same, and cured product of the thermosetting resin composition - Google Patents

Abstract

A urethane resin suitable for forming a flexible film excellent in adhesion to a substrate, folding resistance, low warpage, solder heat resistance, and the like, a thermosetting resin composition containing the urethane resin, and Provided is a printed wiring board on which a protective film or an insulating layer made of a cured product is formed.
A urethane resin includes (a) a polyisocyanate, (b) a compound having two or more alcoholic hydroxyl groups, and (c) one alcoholic hydroxyl group and one or more phenols in one molecule. The component (b) is a polycarbonate diol containing a repeating unit derived from one or more linear aliphatic diols as a constituent unit, It contains at least one selected from the group consisting of a polycarbonate diol containing a repeating unit derived from two or more alicyclic diols as a constituent unit, and a compound having a phenolic hydroxyl group and two or more alcoholic hydroxyl groups.
[Selection figure] None

Description

  The present invention provides a phenolic hydroxyl group suitable for forming a flexible film excellent in adhesion to a substrate, folding resistance, low warpage, solder heat resistance, electroless gold plating resistance, electrical insulation, etc. Urethane resin having, thermosetting resin composition containing the same, and protective film and insulating material made of the cured product, used for the production of printed wiring boards, particularly for the production of flexible printed wiring boards and tape carrier packages Protective films and insulating layers such as solder resists and interlayer insulation films, or back-electrode protective films for electroluminescent panels used in liquid crystal display backlights and information display displays, mobile phones, watches, cars It is useful as a protective film for display panels such as stereo, IC and VLSI sealing materials.

  Solder resist used in the manufacture of flexible printed wiring boards and tape carrier packages is a type that can be applied with an adhesive after punching a polyimide film called a coverlay film with a mold that matches the pattern. There are used a type in which an ultraviolet curable type and thermosetting type solder resist ink for forming a film having a coating is applied by screen printing, and a liquid photo solder resist ink type for forming a film having flexibility.

  However, since the coverlay film has a problem in followability with the copper foil, a highly accurate pattern cannot be formed. On the other hand, in the ultraviolet curable solder resist ink and the liquid photo solder resist ink, the adhesiveness with the polyimide of the base material is poor and sufficient flexibility cannot be obtained. Further, since the curing shrinkage of the solder resist ink and the cooling shrinkage after curing are large, warping occurs, which is a problem.

  In addition, as a conventional thermosetting solder resist ink, an epoxy resin resist ink composition containing an epoxy resin and a dibasic acid anhydride as essential components as disclosed in JP-B-5-75032 (Patent Document 1) Although there is a thing, when it adjusts so that flexibility may be given to the formed film, the adhesiveness with the polyimide of a base material worsens, and there is a problem that plating resistance, PCT resistance, and solder heat resistance fall. is there.

  Therefore, in Japanese Patent Application Laid-Open No. 2006-117922 (Patent Document 2), (A) one molecule has two or more carboxyl groups and is formed by the reaction of polycarbonate diol (a) and polyisocyanate (b). A thermosetting resin composition containing a polyurethane having a urethane bond and (B) a thermosetting component has been proposed. By using such a carboxyl group-containing urethane resin in combination with an epoxy resin as a thermosetting component, the problems of the conventional solder resist ink described above can be solved, but the characteristics such as solder heat resistance should still be improved. The point was left.

Japanese Patent Publication No. 5-75032 (Claims) JP 2006-117922 A (Claims)

  Accordingly, the object of the present invention is to solve the problems of the prior art as described above, adhesion to the substrate, folding resistance, low warpage, solder heat resistance, electroless gold plating resistance, electrical insulation, etc. A urethane resin suitable for forming a flexible film and a thermosetting resin composition containing the same, and a printed wiring having a protective film and an insulating layer made of the cured product at a relatively low cost It is to provide parts or products such as boards, particularly flexible printed wiring boards, tape carrier packages and the like.

In order to achieve the above object, according to the present invention, there is provided a urethane resin having a phenolic hydroxyl group. Moreover, the urethane resin which has a carboxyl group and a phenolic hydroxyl group, More preferably, the urethane resin which has a phenolic hydroxyl group at the terminal is provided.
That is, in a basic embodiment, (a) a polyisocyanate, (b) a compound having two or more alcoholic hydroxyl groups, and (c) one alcoholic hydroxyl group and one or more A urethane resin obtained by reacting a compound having a phenolic hydroxyl group, wherein the component (b) is
(B-1) a polycarbonate diol containing a repeating unit derived from one or more linear aliphatic diols as a constituent unit;
(B-2) a polycarbonate diol containing a repeating unit derived from one or more alicyclic diols as a constituent unit, and (b-3) a phenolic hydroxyl group and two or more alcoholic hydroxyl groups A urethane resin containing at least one selected from the group consisting of compounds is provided.

Moreover, according to this invention, the thermosetting resin composition characterized by including (A) urethane resin which has the said phenolic hydroxyl group, and (B) thermosetting compound is provided.
In a preferred embodiment, the thermosetting compound (B) is an epoxy resin, and preferably further contains (C) a curing accelerator. Furthermore, an inorganic and / or organic filler can be contained, and an organic solvent can be contained as necessary.
Furthermore, according to the present invention, there are also provided a cured product obtained by curing the thermosetting resin composition, and a printed wiring board in which a part or all of the surface is coated with the cured product.

The urethane resin of the present invention is characterized by having a phenolic hydroxyl group or having a carboxyl group and a phenolic hydroxyl group. As a result, the carboxyl group or phenolic hydroxyl group undergoes a crosslinking reaction with the functional group of the thermosetting compound, for example, the epoxy group of the epoxy resin during thermosetting, so that the characteristics such as solder heat resistance can be improved. .
The urethane resin of the present invention is more preferably characterized by having a phenolic hydroxyl group at the terminal. As a result, the phenolic hydroxyl group present at the terminal is more reactive with the epoxy group etc. than the phenolic hydroxyl group present in the main chain, and the characteristics such as solder heat resistance are further improved. Can do.
The urethane resin of the present invention comprises, as a basic aspect, (a) a polyisocyanate, (b) a compound having two or more alcoholic hydroxyl groups, and (c) one alcoholic hydroxyl group in one molecule. It is obtained by reacting a group and a compound having one or more phenolic hydroxyl groups. Since the urethane resin thus obtained has a phenolic hydroxyl group at the terminal, it is possible to improve characteristics such as solder heat resistance as described above.
Therefore, the urethane resin of the present invention is suitable for forming a flexible film excellent in adhesion to a base material, folding resistance, low warpage, solder heat resistance, electroless gold plating resistance, electrical insulation, and the like. Yes.

  In the present invention, the thermosetting resin composition containing the urethane resin having a phenolic hydroxyl group or further a carboxyl group together with a thermosetting compound is suitable for the production of flexible printed wiring boards and tape carrier packages having excellent flexibility. It is useful as a protective film such as a solder resist used and an insulating resin material. Moreover, since the film obtained from such a thermosetting resin composition does not warp after thermosetting, it is easy to mount components or chips on a flexible printed wiring board or a tape carrier package. Therefore, the thermosetting resin composition of the present invention is a flexible protective film excellent in various properties such as adhesion, folding resistance, low warpage, electroless gold plating resistance, solder heat resistance, and electrical insulation. Can be formed at low cost with good productivity.

2 is a graph showing an IR spectrum of a urethane resin having a phenolic hydroxyl group produced in Synthesis Example 1. FIG.

As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that a urethane resin having a phenolic hydroxyl group, that is, (a) a polyisocyanate and (b) a compound having two or more alcoholic hydroxyl groups. And (c) a urethane resin having a phenolic hydroxyl group, which is obtained by reacting a compound having one alcoholic hydroxyl group and one or more phenolic hydroxyl groups in one molecule, It has been found that this phenolic hydroxyl group causes a crosslinking reaction with a functional group of a thermosetting compound, for example, an epoxy group of an epoxy resin, and can improve characteristics such as solder heat resistance. Generally, the lower the crosslink density of the resin, the greater the flexibility of the formed film and the less the warp of the film after thermosetting. However, when the crosslink density is lowered, characteristics such as solder heat resistance, plating resistance, chemical resistance, and the like of the obtained film are likely to be lowered. In the present invention, a compound having one alcoholic hydroxyl group and one or more phenolic hydroxyl groups in one molecule as one of the components of the urethane resin, particularly by introducing a phenolic hydroxyl group into the urethane resin. By using (c) and introducing a phenolic hydroxyl group at the terminal, it was possible to balance these contradictory properties and improve properties such as solder heat resistance of the resulting coating.
Hereinafter, each component of the urethane resin having a phenolic hydroxyl group of the present invention and a thermosetting resin composition containing the same will be described in detail.

  First, the urethane resin (A) of the present invention comprises a polyisocyanate (a), a compound (b) having two or more alcoholic hydroxyl groups, and one alcohol per molecule that also functions as a reaction terminator. It is preferably a urethane resin having a phenolic hydroxyl group introduced at the end by reaction with a compound (c) having a functional hydroxyl group and one or more phenolic hydroxyl groups. A compound obtained by reacting (a) with a compound (b) having two or more alcoholic hydroxyl groups, wherein the compound (b) is a compound having a phenolic hydroxyl group and two or more alcoholic hydroxyl groups. Urethane resin with phenolic hydroxyl groups introduced into the side chain Including urethane resin obtained by introducing a carboxyl group into the molecular side chain with a compound having a cyclohexyl group and two or more alcoholic hydroxyl groups. In the latter urethane resin, the compound (c) having one alcoholic hydroxyl group and one or more phenolic hydroxyl groups in one molecule can be used as a terminal blocking agent (reaction terminator). , Monohydroxyl compounds such as aliphatic alcohols and monohydroxy mono (meth) acrylate compounds, monocarboxylic acids having functional groups capable of undergoing an addition reaction or condensation reaction with isocyanate groups such as alcoholic hydroxyl groups, amino groups, and thiol groups Various conventionally known reaction terminators can be used.

  The urethane resin (A) includes, for example, a polyisocyanate (a), a compound (b) having two or more alcoholic hydroxyl groups, one alcoholic hydroxyl group and one or more phenolic compounds in one molecule. The molecule (c) having a hydroxyl group may be mixed and reacted, or the polyisocyanate (a) and the polyol (b) may be reacted, and subsequently function as a reaction terminator. A compound (c) having one alcoholic hydroxyl group and one or more phenolic hydroxyl groups in it may be reacted. In the case of the other urethane resins described above, the polyisocyanate (a), the phenolic hydroxyl group and / or the carboxyl group and the compound (b) having two or more alcoholic hydroxyl groups, and the reaction terminator are collectively used. Although they may be mixed and reacted, from the viewpoint of adjusting the molecular weight, it is preferable to react the polyisocyanate (a) with the polyol (b) and then react with the reaction terminator.

  The reaction proceeds without catalyst by stirring and mixing at room temperature to 100 ° C, but it is preferable to heat to 70 to 100 ° C in order to increase the reaction rate. The reaction ratio (molar ratio) of the components (a) to (c) is (a) :( b) = 1: 1 to 2: 1, preferably 1: 1 to 1.5: 1. A ratio of a + b) :( c) = 1: 0.01 to 0.5, preferably 0.02 to 0.3 is appropriate.

  As said polyisocyanate (a), conventionally well-known various polyisocyanate can be used, and it is not limited to a specific compound. Specific examples of the polyisocyanate (a) include, for example, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethylene diisocyanate, (o, m, or p) -xylene diisocyanate, (O, m, or p) -hydrogenated xylene diisocyanate, methylene bis (cyclohexyl isocyanate), trimethylhexamethylene diisocyanate, cyclohexane-1,3-dimethylene diisocyanate, cyclohexane-1,4-dimethylene diisocyanate, 1,5-naphthalene And diisocyanates such as diisocyanate. Specifically, toluene diisocyanate and trimethylhexamethylene diisocyanate are preferable. When these diisocyanates are used, a cured product having excellent solder heat resistance can be obtained.

  Next, as the compound (b) having two or more alcoholic hydroxyl groups, a polycarbonate-based polyol such as polycarbonate diol, a compound having a carboxyl group and an alcoholic hydroxyl group, a phenolic hydroxyl group and an alcoholic hydroxyl group are included. A compound etc. can be used conveniently. The polycarbonate diol is derived from a polycarbonate diol (b-1) containing a repeating unit derived from one or more linear aliphatic diols as a constituent unit, derived from one or two or more alicyclic diols. Examples thereof include polycarbonate diol (b-2) containing a repeating unit as a structural unit. When a compound having a phenolic hydroxyl group and two or more alcoholic hydroxyl groups (b-3), a compound having a carboxyl group and two or more alcoholic hydroxyl groups (b-4), etc. are used, A functional group (phenolic hydroxyl group or carboxyl group) can be imparted to the molecular side chain. These compounds (b-1) to (b-3) can be used alone or in admixture of two or more.

  Specific examples of the polycarbonate diol (b-1) containing as a constituent unit a repeating unit derived from one or more linear aliphatic diols are derived from 1,6-hexanediol, for example. Polycarbonate diol, polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol, polycarbonate diol derived from 1,4-butanediol and 1,6-hexanediol, 3-methyl-1,5 -Polycarbonate diol derived from pentanediol and 1,6-hexanediol.

  Specific examples of the polycarbonate diol (b-2) containing a repeating unit derived from one or more alicyclic diols as a constituent unit include, for example, a polycarbonate derived from 1,4-cyclohexanedimethanol. Diol etc. are mentioned.

  If necessary, from polycarbonate diols containing repeating units derived from both linear aliphatic diols and alicyclic diols as constituent units, such as 1,6-hexanediol and 1,4-cyclohexanedimethanol A derived polycarbonate diol or the like can be used.

  Specific examples of the compound (b-4) having a carboxyl group and two or more alcoholic hydroxyl groups include dimethylolpropionic acid and dimethylolbutanoic acid. By using a compound having these carboxyl groups and two or more alcoholic hydroxyl groups, the carboxyl groups can be easily introduced into the urethane resin.

  Specific examples of the compound (b-3) having a phenolic hydroxyl group and two or more alcoholic hydroxyl groups include 6-hydroxy-5-methyl-1,3-benzenedimethanol, 2,4-dimethyl (Hydroxymethyl) -6-cyclohexylphenol, 3,3'-methylenebis (2-hydroxy-5-methyl-benzenemethanol), 4,4 '-(1-methylethylidene) bis [2-methyl-6-hydroxymethyl Phenol], 4,4 ′-[1,4-phenylenebis (1-methylethylidene) bis [2-methyl-6-hydroxymethylphenol], 2-hydroxy-5-fluoro-1,3-benzenedimethanol, 4,4′-methylenebis (2-methyl-6-hydroxymethylphenol), 4,4′-methylenebis (2,5- Methyl-4-hydroxymethylphenol), 4,4′-cyclohexylidenebis (2-methyl-6-hydroxymethylphenol), 4,4′-cyclohexylidenebis (2-cyclohexyl-6-hydroxymethylphenol) 2,6-bis [(2-hydroxy-3-hydroxymethyl-5-methylphenyl) methyl] -4-methylphenol, 2-hydroxy-5-ethyl-1,3-benzenedimethanol, 2-hydroxy- 4,5-dimethyl-1,3-benzenedimethanol, 2-hydroxy-5- (1-methylpropyl) -1,3-benzenedimethanol, 4- (1,1-dimethylethyl) -2-hydroxy- 1,3-benzenedimethanol, 2-hydroxy-5-cyclohexyl-1,3-benzenedimethanol, 2-hydride Xyl-5- (1,1,3,3-tetramethylbutyl) -1,3-benzenedimethanol, 2,6-bis [(4-hydroxy-3-hydroxymethyl-2,5-dimethylphenyl) methyl ] -3,4-dimethylphenol, 2,6-bis [(4-hydroxy-3-hydroxymethyl-2,5-dimethylphenyl) methyl] -4-cyclohexylphenol, 2-hydroxy-1,3,5- Benzene trimethanol, 3,5-dimethyl-2,4,6-trihydroxymethylphenol, 4,4 ′, 4 ″ -ethylidinetris (2-methyl-6-hydroxymethylphenol), 2,3,5 Examples include 6-tetra (hydroxymethyl) -1,4-benzenediol and 4,4′-methylenebis [2,6-bis (hydroxymethyl) phenol]. By using a compound having these phenolic hydroxyl group and alcoholic hydroxyl group, the phenolic hydroxyl group can be easily introduced into the urethane resin.

  A polycarbonate diol containing a repeating unit derived from the linear aliphatic diol as a constituent unit tends to be excellent in low warpage and flexibility. Moreover, the polycarbonate diol which contains the repeating unit derived from alicyclic diol as a structural unit becomes high in crystallinity, and tends to be excellent in tin plating resistance and solder heat resistance. From the above viewpoint, these polycarbonate diols are used in combination of two or more, or, if necessary, polycarbonate diols containing repeating units derived from both linear aliphatic diols and alicyclic diols as constituent units. Can be used. In order to achieve a good balance between low warpage and flexibility, solder heat resistance and tin plating resistance, the copolymerization ratio of the linear aliphatic diol and the alicyclic diol is 3: 7 to 7 by mass ratio. : 3 polycarbonate diol is preferably used.

  The polycarbonate diol preferably has a number average molecular weight of 200 to 5,000, but the polycarbonate diol contains a repeating unit derived from a linear aliphatic diol and an alicyclic diol as a structural unit, and a linear aliphatic diol. When the copolymerization ratio of the alicyclic diol and the alicyclic diol is from 3: 7 to 7: 3, the number average molecular weight is preferably from 400 to 2,000.

  The compound (c) having one alcoholic hydroxyl group and one or more phenolic hydroxyl groups in one molecule is used for the purpose of introducing a phenolic hydroxyl group into polyurethane, and is also used as an end-capping agent for polyurethane. Any compound that has one alcoholic hydroxyl group and one phenolic hydroxyl group that functions and can react with an isocyanate in the molecule functions as a reaction terminator. Specific examples of such a compound (c) include, for example, hydroxymethylphenol, hydroxymethylcresol, hydroxymethyl-di-t-butylphenol, p-hydroxyphenyl-2-methanol, p-hydroxyphenyl-3-propanol, p -Hydroxyphenyl-4-butanol, hydroxyethylcresol, 2,6-dimethyl-4-hydroxymethylphenol, 2,4-dimethyl-6-hydroxymethylphenol, 2,3,6-trimethyl-4-hydroxymethylphenol, 2-cyclohexyl-4-hydroxymethyl-5-methylphenol, 4-methyl-6-hydroxymethylbenzene-1,2-diol, 4- (1,1-dimethylethyl) -6-hydroxymethylbenzene-1,2 -Hydroxy such as diol Alkylphenol or hydroxyalkylcresol; phenol having a carboxyl group-containing substituent such as hydroxybenzoic acid, hydroxyphenylbenzoic acid, or hydroxyphenoxybenzoic acid, and ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene Examples thereof include, but are not limited to, esterified products with glycol and the like; monoethylene oxide adducts of bisphenol, monopropylene oxide adducts of bisphenol, p-hydroxyphenethyl alcohol, and the like. These compounds (c) can be used alone or in admixture of two or more.

  The weight average molecular weight of the urethane resin (A) having a phenolic hydroxyl group is preferably 500 to 100,000, and more preferably 8,000 to 50,000. Here, the weight average molecular weight is a value in terms of polystyrene measured by gel permeation chromatography. When the weight average molecular weight of the urethane resin (A) having a phenolic hydroxyl group is less than 500, the elongation, flexibility, and strength of the cured film may be impaired. On the other hand, when it exceeds 100,000, the solubility in a solvent is increased. In addition, since the viscosity becomes too high even when dissolved, restrictions on use are increased.

  In the thermosetting resin composition of the present invention, as the thermosetting compound (B) blended together with the urethane resin (A) having the phenolic hydroxyl group, the phenolic hydroxyl of the urethane resin as the component (A) Epoxy resins and oxetane compounds having two or more epoxy groups, oxetanyl groups and the like that can react with a group (or further carboxyl group) in one molecule can be suitably used, and epoxy resins are particularly preferable.

  Specific examples of the epoxy resin include, for example, bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, novolac type epoxy resin, phenol Novolac epoxy resin, cresol novolac epoxy resin, N-glycidyl epoxy resin, bisphenol A novolac epoxy resin, bixylenol epoxy resin, biphenol epoxy resin, chelate epoxy resin, glyoxal epoxy resin, amino group-containing Epoxy resin, rubber-modified epoxy resin, dicyclopentadiene phenolic epoxy resin, diglycidyl phthalate resin, heterocyclic epoxy resin, tetraglycidyl chloride Renoiruetan resins, silicone-modified epoxy resins, such as ε- caprolactone-modified epoxy resin. Further, in order to impart flame retardancy, a material in which an atom such as halogen such as chlorine or bromine or phosphorus is introduced into the structure may be used.

  In the thermosetting resin composition of the present invention, the thermosetting compound (B) is used alone or as a mixture of two or more. The blending amount is 5 to 150 parts by mass, preferably 10 to 80 parts by mass with respect to 100 parts by mass of the urethane resin having a phenolic hydroxyl group as the component (A). If it is less than 5 parts by mass, the solder heat resistance of the cured film of the thermosetting resin composition may be insufficient. On the other hand, if it exceeds 150 parts by mass, it is used as an insulating protective film for a flexible printed circuit board (FPC). In this case, various characteristics, particularly electrical insulation, tend to deteriorate.

  The curing accelerator (C) used in the present invention accelerates the thermosetting reaction and is used to further improve the properties such as adhesion, chemical resistance, and heat resistance. Specific examples of such a curing accelerator include imidazole and derivatives thereof (for example, 2MZ, 2E4MZ, C11Z, C17Z, 2PZ, 1B2MZ, 2MZ-CN, 2E4MZ-CN, C11Z-CN, manufactured by Shikoku Chemical Industry Co., Ltd.). 2PZ-CN, 2PHZ-CN, 2MZ-CNS, 2E4MZ-CNS, 2PZ-CNS, 2MZ-AZINE, 2E4MZ-AZINE, C11Z-AZINE, 2MA-OK, 2P4MHZ, 2PHZ, 2P4BHZ, etc.); Guanamines; polyamines such as diaminodiphenylmethane, m-phenylenediamine, m-xylenediamine, diaminodiphenylsulfone, dicyandiamide, urea, urea derivatives, melamine, polybasic hydrazides; their organic acid salts and / or epoxies Duct; amine complex of boron trifluoride; triazine derivatives such as ethyldiamino-S-triazine, 2,4-diamino-S-triazine, 2,4-diamino-6-xylyl-S-triazine; trimethylamine, triethanol Amine, N, N-dimethyloctylamine, N-benzyldimethylamine, pyridine, N-methylmorpholine, hexa (N-methyl) melamine, 2,4,6-tris (dimethylaminophenol), tetramethylguanidine, m- Amines such as aminophenol; polyphenols such as polyvinylphenol, polyvinylphenol bromide, phenol novolak, alkylphenol novolak; organic phosphines such as tributylphosphine, triphenylphosphine, tris-2-cyanoethylphosphine; Phosphonium salts such as tri-n-butyl (2,5-dihydroxyphenyl) phosphonium bromide and hexadecyltributylphosphonium chloride; quaternary ammonium salts such as benzyltrimethylammonium chloride and phenyltributylammonium chloride; the polybasic acid anhydrides; diphenyl Iodonium tetrafluoroboroate, triphenylsulfonium hexafluoroantimonate, 2,4,6-triphenylthiopyrylium hexafluorophosphate, manufactured by Ciba Geigy, Irgacure 261, manufactured by Asahi Denka Co., Ltd., Optoma-SP- 170 photocatalytic polymerization catalyst; styrene-maleic anhydride resin; equimolar reaction product of phenyl isocyanate and dimethylamine, tolylene diisocyanate, isophorone diiso Organic polyisocyanate and a curing accelerator or curing agents are conventionally known, such as equimolar reaction product of dimethylamine, such Aneto like.

  These curing accelerators (C) can be used alone or in admixture of two or more. The use of a curing accelerator (C) is not essential, but particularly when it is desired to accelerate curing, it is preferably used in a range of 0.1 to 25 parts by mass with respect to 100 parts by mass of the thermosetting compound (B). be able to. If it exceeds 25 parts by mass, the sublimable component from the cured product increases, which is not preferable.

  The thermosetting resin composition of the present invention comprises a urethane resin (A) having a phenolic hydroxyl group, a thermosetting compound (B) and, if necessary, a curing accelerator (C), a mixer such as a disper, It can be obtained by dissolving or dispersing using a kneader, a three-roll mill, a bead mill or the like. In that case, you may use the solvent inactive with respect to an epoxy group or a phenolic hydroxyl group. Such an inert solvent is preferably an organic solvent.

  The organic solvent is used for easily dissolving or dispersing the urethane resin (A) having the phenolic hydroxyl group and the thermosetting compound (B), or adjusting the viscosity to be suitable for coating. Examples of the organic solvent include toluene, xylene, ethylbenzene, nitrobenzene, cyclohexane, isophorone, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, carbitol acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, dipropylene glycol methyl ether acetate, Diethylene glycol ethyl ether acetate, methyl methoxypropionate, ethyl methoxypropionate, methyl ethoxypropionate, ethyl ethoxypropionate, ethyl acetate, n-butyl acetate, isoamyl acetate, ethyl lactate, acetone, methyl ethyl ketone, cyclohexanone, N, N-dimethyl Formamide, N, N-dimethylacetamide, - it includes methyl pyrrolidone, .gamma.-butyrolactone, dimethyl sulfoxide, chloroform and methylene chloride. The blending amount of the organic solvent can be appropriately set according to the desired viscosity.

  The thermosetting resin composition of this invention can contain a well-known and usual mercapto compound in order to improve adhesiveness with base materials, such as a polyimide, as needed. Examples of mercapto compounds include 2-mercaptopropionic acid, trimethylolpropane tris (2-thiopropionate), 2-mercaptoethanol, 2-aminothiophenol, 3-mercapto-1,2,4-triazole, and 3-mercapto. -A mercapto group-containing silane coupling agent such as propyltrimethoxysilane. These may be used alone or in combination of two or more. The blending amount is suitably in the range of 10 parts by mass or less per 100 parts by mass of the urethane resin (A) having a phenolic hydroxyl group. When the blending amount of the mercapto compound exceeds the above range, it is not preferable because the epoxy group of the epoxy resin necessary for the crosslinking reaction is consumed (reacts with the epoxy group) and the crosslinking density is lowered.

  The thermosetting resin composition of the present invention may further contain an inorganic and / or organic filler as necessary for the purpose of improving properties such as adhesion, hardness, and heat resistance. Examples of the inorganic filler include barium sulfate, calcium carbonate, barium titanate, silicon oxide, amorphous silica, talc, clay, and mica powder. Examples of the organic filler include silicon powder, nylon powder, and fluorine powder. . Among the fillers, silica is particularly excellent in low hygroscopicity and low volume expansion. Silica may be a mixture of these materials regardless of melting or crystallinity, but in particular, silica surface-treated with a coupling agent or the like is preferable because it can improve electrical insulation. The average particle size of the filler is desirably 25 μm or less, more preferably 10 μm or less, and still more preferably 3 μm or less. The blending amount of these inorganic and / or organic fillers is suitably 300 parts by mass or less, preferably 5 to 150 parts by mass, per 100 parts by mass of the urethane resin (A) having a phenolic hydroxyl group. When the blending amount of the filler exceeds the above ratio, the folding resistance of the cured film is lowered, which is not preferable.

  Furthermore, in the thermosetting resin composition of the present invention, other additives and colorants other than the above components may be added as long as the effects of the present invention are not impaired. Additives include thickeners such as asbestos, olven, and benton, silicone-based and fluorine-based antifoaming agents, leveling agents, fiber reinforcements such as glass fibers, carbon fibers, and boron nitride fibers, and coloring agents. Examples include phthalocyanine blue, phthalocyanine green, iodin green, disazo yellow, titanium oxide, and carbon black. Furthermore, if necessary, known and commonly used thermal polymerization inhibitors, ultraviolet absorbers, silane coupling agents, plasticizers, foaming agents, flame retardants, antistatic agents, anti-aging agents, antibacterial / antifungal agents, and the like can be added. .

The thermosetting resin composition having the above composition can be applied to a printed circuit board by various known methods such as curtain coating, roll coating, spray coating, and dip coating, as well as dry film. Alternatively, it can be used for various forms and applications such as prepreg. Various solvents can be used depending on the method of use and application, but in some cases, not only good solvents but also poor solvents can be used.
The thermosetting resin composition of the present invention is applied to a flexible printed wiring board, a tape carrier package or an electroluminescent panel on which a circuit is formed by a screen printing method, and heated to a temperature of 120 to 180 ° C., for example. Solder resist film with excellent adhesion to substrate, folding resistance, low warpage, electroless gold plating resistance, solder heat resistance, electrical insulation, etc. And a protective film is formed.

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. In the following, “parts” and “%” are based on mass unless otherwise specified.

Synthesis example 1
A polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol as a compound having two or more alcoholic hydroxyl groups in a reaction vessel equipped with a stirrer, a thermometer, and a condenser (Ube Industries, Ltd.) ), PCDL800, number average molecular weight 800) 360 g (0.45 mol), dimethylolbutanoic acid 81.4 g (0.55 mol), and one alcoholic hydroxyl group and one or more phenolic per molecule As a compound having a hydroxyl group, 22.1 g (0.16 mol) of hydroxyphenylethyl alcohol was added. Next, 187.9 g (1.08 mol) of tolylene diisocyanate was added as a polyisocyanate, and the mixture was heated to 60 ° C. with stirring and stopped. When the temperature in the reaction vessel began to decrease, the mixture was heated again to 80 ° C. Stirring was continued at 0 ° C., and the reaction was terminated after confirming that the absorption spectrum (2280 cm ⁻¹ ) of the isocyanate group had disappeared in the infrared absorption spectrum. Subsequently, carbitol acetate was added so that a solid content might be 50 wt%, and the urethane resin (varnish A) which has the phenolic hydroxyl group of the viscous liquid containing a diluent was obtained. The acid value of the solid content of the obtained urethane resin was 50.1 mgKOH / g. The IR spectrum of the obtained urethane resin having a phenolic hydroxyl group is shown in FIG.

Synthesis example 2
A polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol as a compound having two or more alcoholic hydroxyl groups in a reaction vessel equipped with a stirrer, a thermometer, and a condenser (Ube Industries, Ltd.) ), PCDL800, number average molecular weight 800) 360 g (0.45 mol), dimethylolbutanoic acid 81.4 g (0.55 mol), and one alcoholic hydroxyl group and one or more phenolic per molecule As a compound having a hydroxyl group, 22.1 g (0.16 mol) of hydroxyphenylethyl alcohol was added. Next, 83.5 g (0.48 mol) of tolylene diisocyanate and 111.6 (0.60 mol) of tolylene diisocyanate were added as polyisocyanates, and the mixture was heated to 60 ° C. with stirring and stopped. When the temperature began to decrease, the mixture was heated again and stirred at 80 ° C., and the reaction was terminated after confirming that the absorption spectrum of the isocyanate group (2280 cm ⁻¹ ) disappeared in the infrared absorption spectrum. Subsequently, carbitol acetate was added so that a solid content might be 50 wt%, and the urethane resin (varnish B) which has the phenolic hydroxyl group of the viscous liquid containing a diluent was obtained. The acid value of the solid content of the obtained urethane resin was 49.2 mgKOH / g.

Synthesis example 3
A polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol as a compound having two or more alcoholic hydroxyl groups in a reaction vessel equipped with a stirrer, a thermometer, and a condenser (Ube Industries, Ltd.) ), PCDL800, number average molecular weight 800) 800 g (1.00 mol), and 22.1 g of hydroxyphenylethyl alcohol as a compound having one alcoholic hydroxyl group and one or more phenolic hydroxyl groups in one molecule ( 0.16 mol) was added. Next, 187.9 g (1.08 mol) of tolylene diisocyanate was added as a polyisocyanate, and the mixture was heated to 60 ° C. with stirring and stopped. When the temperature in the reaction vessel began to decrease, the mixture was heated again to 80 ° C. Stirring was continued at 0 ° C., and the reaction was terminated after confirming that the absorption spectrum (2280 cm ⁻¹ ) of the isocyanate group had disappeared in the infrared absorption spectrum. Subsequently, carbitol acetate was added so that a solid content might be 50 wt%, and the urethane resin (varnish C) which has the phenolic hydroxyl group of the viscous liquid containing a diluent was obtained.

Varnish D:
Acrylic copolymer resin manufactured by Daicel Chemical Industries, Ltd .; cyclomer ACA Z250 (solid content acid value 70.0 mgKOH / g) was used as varnish D.

Examples 1 to 4 and Comparative Example 1
Each component and blending ratio shown in Table 1 were mixed with three rolls at room temperature to prepare a thermosetting resin composition. The obtained thermosetting resin composition was applied to a substrate so as to have a film thickness of about 15 μm by screen printing, and thermosetting was performed at 150 ° C. for 60 minutes.

About the cured film of each said thermosetting resin composition, the following various characteristics were evaluated with the following method. The results are shown in Table 2.
(1) Adhesiveness Each of the thermosetting resin compositions of Examples 1 to 4 and Comparative Example 1 was printed on the entire surface by screen printing on Kapton 200H (a polyimide film manufactured by Toray DuPont Co., Ltd., thickness 50 μm). Thermal curing was performed at 150 ° C. for 60 minutes (dry film thickness: 15 μm). The adhesiveness of the cured film was evaluated according to JIS D 0202 according to the following criteria.
○: When the number of grids remains completely △: When the number of grids is less than 100 and 60 or more remain ×: When the number of grids remains less than 60

(2) Folding resistance Each of the thermosetting resin compositions of Examples 1 to 4 and Comparative Example 1 was printed on the entire surface by screen printing on Kapton 200H (a polyimide film manufactured by Toray DuPont Co., Ltd., thickness 50 μm). And thermosetting at 150 ° C. for 60 minutes (dry film thickness: 15 μm). The obtained cured film was bent 180 ° and evaluated according to the following criteria.
○: The cured film has no cracks Δ: The cured film has some cracks ×: The cured film has cracks

(3) Low warpage Each of the thermosetting resin compositions of Examples 1 to 4 and Comparative Example 1 was printed on the entire surface by screen printing on Kapton 200H (a polyimide film manufactured by Toray DuPont Co., Ltd., thickness 50 μm). And thermosetting at 150 ° C. for 60 minutes (dry film thickness: 15 μm). After cooling, the obtained cured film was cut into 50 × 50 mm, and the warpage was evaluated according to the following criteria.
○: No warping Δ: Some warping ×: Warping

(4) Resistance to electroless gold plating Each of the thermosetting resin compositions of Examples 1 to 4 and Comparative Example 1 was pattern-printed on a printed circuit board (thickness 1.6 mm) and heated at 150 ° C. for 60 minutes. Cured to obtain a test piece (dry film thickness 15 μm). Using the obtained test piece, electroless gold plating was performed in the steps described later, and the electroless gold plating resistance was evaluated according to the following criteria.
○: The cured film has no blistering, peeling, or discoloration △: The cured film has slight blistering, peeling, or discoloration ×: The cured film has blistering, peeling, or discoloration

Electroless gold plating process:
1. Degreasing: The test piece was immersed in an acidic degreasing solution at 30 ° C. (manufactured by Nippon MacDermid Co., Ltd., 20 vol% aqueous solution of Metex L-5B) for 3 minutes.
2. Water washing: The test piece was immersed in running water for 3 minutes.
3. Soft etching: The test piece was immersed in an aqueous solution of 14.3 wt% ammonium persulfate for 1 minute at room temperature.
4). Water washing: The test piece was immersed in running water for 3 minutes.
5. Acid immersion: The test piece was immersed in a 10 vol% sulfuric acid aqueous solution at room temperature for 1 minute.
6). Rinsing: The test piece was immersed in running water for 30 seconds to 1 minute.
7). Application of catalyst: The test piece was immersed in a 30 ° C. catalyst solution (manufactured by Meltex, 10 vol% aqueous solution of metal plate activator 350) for 3 minutes.
8). Water washing: The test piece was immersed in running water for 3 minutes.
9. Electroless nickel plating: The test piece was immersed in a nickel plating solution (Meltex, Melplate Ni-865M, 20 vol% aqueous solution) at 85 ° C. and pH = 4.6 for 30 minutes.
10. Acid immersion: The test piece was immersed in a 10 vol% sulfuric acid aqueous solution at room temperature for 1 minute.
11. Rinsing: The test piece was immersed in running water for 30 seconds to 1 minute.
12 Electroless gold plating: The test piece was immersed for 30 minutes in a gold plating solution (manufactured by Meltex Co., Ltd., Aurolectroles UP15 vol%, potassium gold cyanide 3 wt% aqueous solution) at 85 ° C. and pH = 6.
13. Water washing: The test piece was immersed in running water for 3 minutes.
14 Hot water washing: The test piece was immersed in warm water of 60 ° C. and thoroughly washed with water for 3 minutes, and then the water was thoroughly dried.

(5) Solder heat resistance Each of the thermosetting resin compositions of Examples 1 to 4 and Comparative Example 1 is printed on a printed circuit board (thickness: 1.6 mm) and thermally cured at 150 ° C. for 60 minutes. (Dry film thickness 15 μm). A rosin-based flux was applied to the obtained cured film and immersed in a solder bath at 260 ° C. for 10 seconds, and the state of the cured film was evaluated according to the following criteria.
○: The cured film has no blistering, peeling, or discoloration △: The cured film has slight blistering, peeling, or discoloration ×: The cured film has blistering, peeling, or discoloration

(6) Electrical Insulation Each of the thermosetting resin compositions of Examples 1 to 4 and Comparative Example 1 is L / S = 20/20 μm polyimide substrate (Kapton EN, Espanex manufactured by Toray DuPont Co., Ltd.) A coating film was formed thereon and thermally cured at 150 ° C. for 60 minutes (dry film thickness 15 μm). The electrical insulation of the obtained cured film was evaluated according to the following criteria.
Humidification conditions: temperature 120 ° C., humidity 85% RH, 0.17 MPa, applied voltage 60 V, 100 hours Measurement conditions: measurement time 60 seconds, applied voltage 60 V
○: Insulation resistance value after humidification of 10 ⁹ Ω or more, no copper migration Δ: Insulation resistance value after humidification of 10 ⁹ Ω or more, copper migration ×: Insulation resistance value after humidification of 10 ⁸ Ω or less, copper migration Yes

  As is clear from the results shown in Table 2 above, the cured film formed from the thermosetting resin composition of the present invention has adhesion to a substrate, folding resistance, low warpage, electroless gold plating resistance, solder Excellent heat resistance. Also, the insulation reliability was good. On the other hand, in the case of Comparative Example 1 using an acrylic copolymer-based carboxyl group-containing resin (varnish D), there was no problem in adhesion to the substrate, electroless gold plating resistance, and electrical insulation, It was inferior in folding resistance and low warpage.

Claims (8)

(A) a polyisocyanate, (b) a compound having two or more alcoholic hydroxyl groups, and (c) a compound having one alcoholic hydroxyl group and one or more phenolic hydroxyl groups in one molecule. A urethane resin obtained by reaction, wherein the component (b) is
(B-1) a polycarbonate diol containing a repeating unit derived from one or more linear aliphatic diols as a constituent unit;
(B-2) a polycarbonate diol containing a repeating unit derived from one or more alicyclic diols as a constituent unit, and (b-3) a phenolic hydroxyl group and two or more alcoholic hydroxyl groups A urethane resin containing at least one selected from the group consisting of compounds.   The urethane resin according to claim 1, wherein the component (b) further comprises (b-4) a compound having a carboxyl group and two or more alcoholic hydroxyl groups.   (A) A thermosetting resin composition comprising the urethane resin according to claim 1 or 2 and (B) a thermosetting compound.   The thermosetting resin composition according to claim 3, wherein the thermosetting compound (B) is an epoxy resin.   The thermosetting resin composition according to claim 3 or 4, further comprising (C) a curing accelerator.   Furthermore, an inorganic and / or organic filler is contained, The thermosetting resin composition of any one of Claims 3-5 characterized by the above-mentioned.   Hardened | cured material formed by hardening | curing the thermosetting resin composition of any one of the said Claims 3-6.   The printed wiring board by which one part or all part of the surface was coat | covered with the hardened | cured material of the thermosetting resin composition of any one of the said Claims 3-6.

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