KR20100076016A - Resin composition - Google Patents

Abstract

Disclosed is a resin composition which is excellent in solvent resistance, flexibility (bendability), low warping property, and electrical insulation. This resin composition is useful as an overcoating agent for flexible printed wiring boards. Specifically disclosed is a resin composition for overcoats of flexible printed wiring boards, which contains a polyurethane resin having an epoxy group and a urethane structure, and an epoxy curing agent.

Description

Resin composition

This invention relates to the resin composition useful as an overcoat agent which protects the electronic circuit surface of a flexible printed circuit board, the flexible printed wiring board whose surface was protected by the hardened | cured material of the said resin composition, and the electronic apparatus which incorporates the said flexible printed wiring board.

Flexible printed wiring boards (FPCs) used in TCP (Tape Carrier Package), COF (Chip On Flexible or Film), etc., generally have a conductor layer formed on one or both surfaces of a film of polyester terephthalate or polyimide. And a surface protective film protecting the surface of the substrate. As an insulating protective film for FPC, generally, the method of sticking the coverlay film which provided the adhesive bond layer to the board | substrate which made the polyimide film perforate the desired shape with a metal mold | die, and the varnish-like resin composition (made by the overcoat) screen printing The method of printing in a desired pattern and hardening this is known. Since the method of using a coverlay film becomes disadvantageous in terms of workability and cost, the method of coating an overcoat agent by screen printing becomes the mainstream. As an overcoat agent for flexible printed wiring boards, the composition which consists of an epoxy resin, an imidazole compound, and a long chain dibasic acid anhydride is disclosed by Unexamined-Japanese-Patent No. 5-75032, for example.

The overcoat agent for flexible printed wiring boards requires a material which simultaneously satisfies performances such as solvent resistance, flexibility (flexibility), low warpage, and electrical insulation. Therefore, an object of this invention is to provide the resin composition useful as an overcoat agent of a flexible printed wiring board which is excellent in such a characteristic.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, the resin composition containing the epoxy resin and the polyurethane resin which has an urethane structure, and an epoxy hardening | curing agent is excellent in the said characteristic, and excellent for the overcoat of a flexible printed wiring board. It turned out to be a resin composition, and completed this invention. That is, this invention includes the following content.

[1] A resin composition for overcoat of a flexible printed wiring board containing (A) an epoxy group having a epoxy group and a urethane structure, and (B) an epoxy curing agent.

[2] The resin composition according to the item [1], wherein the polyurethane resin further has at least one structure selected from a polycarbonate structure, a polydiene structure, a polyester structure, and a polyether structure.

[3] The resin composition according to the item [1], wherein the polyurethane resin further has a polycarbonate structure and / or a polydiene structure.

[4] The resin composition according to the item [1], wherein the polyurethane resin further has a polycarbonate structure.

[5] The polyol compound according to any one of the above items [1] to [4], wherein the polyurethane resin is (a) a polyol compound having two or more hydroxyl groups in the molecule, and (b) one or more hydroxyl groups in the molecule. A resin composition, which is a polyurethane resin obtained by reacting an epoxy compound having at least one epoxy group and (c) a polyisocyanate compound having at least two isocyanate groups in a molecule.

[6] The resin composition according to the above [5], wherein the polyol compound is at least one polyol compound selected from polycarbonate polyols, polydiene polyols, polyester polyols, and polyether polyols.

[7] The resin composition according to the above [5], wherein the polyol compound is a polycarbonate polyol and / or a polydiene polyol.

[8] The resin composition according to the above [5], wherein the polyol compound is a polycarbonate polyol.

[9] The resin composition according to any one of the above items [1] to [8], wherein (B) the epoxy curing agent is an acid anhydride compound.

[10] The resin composition according to any one of the above items [1] to [8], wherein (B) the epoxy curing agent is a tetrabasic dianhydride.

[11] The resin composition according to any one of the above items [1] to [10], further comprising (C) an oxazoline compound.

[12] The resin composition according to the item [11], wherein the (C) oxazoline compound is a bisoxazoline compound.

[13] The resin composition according to any one of the above items [1] to [12], wherein the resin composition is a pasty resin composition.

[14] The resin composition according to any one of the above items [1] to [13], further containing a curing accelerator.

[15] A flexible printed wiring board whose surface is protected by a cured product of the resin composition according to any one of items [1] to [14].

[16] An electronic device containing the flexible printed wiring board according to item [15].

[17] A resin composition containing (A) a polyurethane resin having an epoxy group and a urethane structure, (B) an epoxy curing agent, and (C) an oxazoline compound.

[18] The resin composition according to the above [17], wherein the polyurethane resin further has a polycarbonate structure and / or a polydiene structure.

[19] The resin composition according to the above [17], wherein the polyurethane resin further has a polycarbonate structure.

[20] The polyurethane resin according to any one of the above items [17] to [19], wherein the polyurethane resin is (a) a polyol compound having two or more hydroxyl groups in the molecule, and (b) one or more hydroxyl groups in the molecule. A resin composition, which is a polyurethane resin obtained by reacting an epoxy compound having at least one epoxy group and (c) a polyisocyanate compound having at least two isocyanate groups in a molecule.

[21] The resin composition according to the above [20], wherein the polyol compound is a polycarbonate polyol and / or a polydiene polyol.

[22] The resin composition according to the above [20], wherein the polyol compound is a polycarbonate polyol.

[23] The resin composition according to any one of items [17] to [22], wherein the epoxy curing agent is an acid anhydride compound.

[24] The resin composition according to any one of items [17] to [22], wherein the epoxy curing agent is a tetrabasic acid dianhydride.

[25] The resin composition according to any one of items [17] to [24], wherein the oxazoline compound is a bisoxazoline compound.

[26] The resin composition according to any one of items [17] to [25], wherein the resin composition is a paste-like resin composition.

The resin composition of this invention is excellent in solvent resistance, flexibility (flexibility), low curvature, and electrical insulation, and becomes a resin composition excellent for the overcoat of a flexible printed wiring board.

"Polyurethane resin which has an epoxy group and a urethane structure" of component (A) in this invention is a polycarbonate structure, a polydiene structure, a polyester structure, or a polyether structure from a viewpoint of fully exhibiting the effect of this invention. It is preferable to have further. Among these structures, polycarbonate structures and polybutadiene structures are preferable, and polycarbonate structures are particularly preferable. In 1 molecule of the polyurethane resin which has an epoxy group and a urethane structure, these 2 or more types of structures may be contained simultaneously.

"Polyurethane resin having an epoxy group and a urethane structure" is preferably a polyol compound having two or more hydroxyl groups in (a) a molecule, and (b) one or more hydroxyl groups and one or more epoxy groups in a molecule. It can be obtained by reacting an epoxy compound having a compound and (c) a polyisocyanate compound having two or more isocyanate groups in a molecule.

As a polyol compound which has two or more hydroxyl groups in the molecule | numerator of raw material (a), a polycarbonate polyol, a polydiene polyol, polyester polyol, a polyether polyol, etc. are mentioned.

Examples of the polyester polyols include azate-based polyols such as polyethylene azate polyols and polybutylene azate polyols, terephthalic acid-based polyols, and polycaprolactone polyols. You may use a polyol compound in combination of 2 or more type.

Examples of the polyether polyol include polypropylene glycol, polytetramethylene ether glycol, polyvinyl ether polyol, and the like. As a polyvinyl ether polyol, TOE-2000H (made by Kyowa Hakko Chemical Co., Ltd.) etc. is mentioned.

As a polydiene polyol, a polybutadiene polyol, a polyisoprene polyol, etc. are mentioned. As a polydiene polyol, you may use hydrogenated polydiene polyol, such as a hydrogenated polybutadiene polyol and a hydrogenated polyisoprene polyol. As a polybutadiene polyol, hydroxyl group terminal liquid polybutadiene Polybd R-45HT which mainly has a 1, 4- bond, R-15HT (refer to the above-mentioned Idemitsukosan Co., Ltd. product), hydroxyl group terminal polybutadiene hydride Polytel H, polytel HA (see above, manufactured by Mitsubishi Chemical Co., Ltd.), terminal hydroxylated polybutadiene having mainly 1,2-bonds G-1000, G-2000, G-3000. Nippon Soda Co., Ltd.], hydrides GI-1000, GI-2000, and GI-3000 of terminal hydroxylated polybutadiene resins mainly having the above 1,2-bonds (refer to the above Nihon Soda Co., Ltd.) Etc. can be mentioned. Examples of the polyisoprene polyols include hydroxyl group terminal liquid isoprene Poly ip and epole (see above; manufactured by Idemitsuko Co., Ltd.).

As a polycarbonate polyol, the polycarbonate polyol containing the repeating unit derived from 1 type, or 2 or more types of diols among polyols, such as linear aliphatic diol, alicyclic diol, and glycerin, is mentioned. Examples of linear aliphatic diols include 1,6-hexanediol, 1,5-pentanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-methyl-1, 8-octanediol, etc. are mentioned. As an alicyclic diol, 1, 4- cyclohexane dimethanol is mentioned.

Among these polyols, polybutadiene polyols and polycarbonate polyols are preferable, and polycarbonate polyols are preferable in view of water resistance, heat resistance and flexibility. As the polybutadiene polyol, polybutadiene diol is particularly preferable, and as the polycarbonate polyol, polycarbonate diol is particularly preferable.

The number average molecular weight of the polyol is preferably 400 to 5,000. When the number average molecular weight is less than 400, the flexibility of the cured product of the resin composition tends to be lowered. When the number average molecular weight exceeds 5,000, the solubility of the polyurethane resin in the solvent tends to be lowered.

Examples of the epoxy compound having at least one hydroxyl group and at least one epoxy group in the molecule of the starting material (b) include at least one hydroxyl group in the molecule, a glycidyl ether structure, a glycidyl ester structure, a glycidyl amine structure, and an alicyclic ring. The epoxy compound which has one or more epoxy groups chosen from a formula epoxy structure and an oxirane ring structure is mentioned. As what is marketed, the epoxy compound which has a 1 or more hydroxyl group and 1 or more glycidyl ether structure in a molecule | numerator, Epicoat 1001, Epocoat 1004 (made by Japan Epoxy Resin Co., Ltd.), etc. are mentioned, As an epoxy compound which has 1 or more hydroxyl group and 1 or more oxirane ring structure in a molecule | numerator, hydroxyl group terminal epoxidized polybutadiene PB-3600 (made by Daicel Chemical Co., Ltd.) is mentioned.

(b) An epoxy compound having at least one hydroxyl group and at least one epoxy group in a molecule includes (d) an epoxy compound having at least two epoxy groups in a molecule and (e) a compound having at least one active hydrogen group reacting with an epoxy group in a molecule. It can also be obtained by making it react.

Examples of the epoxy compound having two or more epoxy groups in the molecule of the raw material (d) include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, hydrogenated bisphenol A type epoxy resins, hydrogenated bisphenol F type epoxy resins, and phenol nos. Volac type epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, alkylphenol novolac type epoxy resin, biphenol type epoxy resin, naphthalene type epoxy resin, aromatic aldehyde having phenol and phenolic hydroxyl group Epoxide of condensate with, triglycidyl isocyanurate, alicyclic epoxy resin, glycidylamine resin, glycidyl ester resin, diglycidyl ether of aliphatic diol, diglycidyl ether of alicyclic diol Epoxy resins, such as these, are mentioned. You may use these epoxy compounds in combination of 2 or more type.

As a compound which has one or more active hydrogen groups which react with an epoxy group in the molecule | numerator of raw material (e), the compound which has one or more phenolic hydroxyl groups, the compound which has one or more carboxyl groups, etc. are mentioned. When it has three or more active hydrogen groups, since it may gelatinize during reaction with an epoxy compound, as compound (e), what has one or two active hydrogen groups is preferable. As a compound which has one active hydrogen group, a phenol compound, a thiophenol compound, a carboxylic acid compound, etc. are mentioned. Examples of the compound having two active hydrogen groups include bisphenol A, bisphenol F, bisphenol S, biphenol, hydroquinone, azipic acid, sebacic acid, dodecane diacid, 8,12-eicosadiene diacid and eicosadiic acid. Etc. can be mentioned. You may use these compounds in combination of 2 or more type.

Raw material (d) and (e) can be made to react in the range of 1 to 8 hours normally at reaction temperature of 80-180 degreeC. An organic solvent may be added to reaction as needed, and a catalyst may be added as needed. Examples of the catalyst include nitrogen compounds, phosphorus compounds and the like.

As a polyisocyanate compound which has two or more isocyanate groups in the molecule | numerator of raw material (c), 2, 4-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, di And cyclohexyl methane diisocyanate, naphthalene diisocyanate, xylene diisocyanate, hydrogenated xylene diisocyanate, tetramethylene xylene diisocyanate, trimethylhexamethylene diisocyanate, norbornene diisocyanate. You may use these polyisocyanate compounds in combination of 2 or more type.

As reaction conditions of a raw material (a), (b), and (c), it can react in the range of reaction temperature of 15-120 degreeC and reaction time normally 1 to 8 hours, for example in an organic solvent. Moreover, you may react by adding a catalyst as needed.

The reaction ratios of the raw materials (a), (b) and (c) are the numbers of the hydroxyl groups of the raw material (a) as Xa and the number of the hydroxyl groups of the raw material (b) as Xb and the isocyanate groups of the raw material (c). When the number of is Y, the range in which the value of (Xa + Xb) / Y becomes 1 to 3 is preferable, and the range that becomes 1.01 to 2 is more preferable. When this ratio is less than 1.0, an isocyanate group will react in excess, and it will become difficult to control molecular weight, and when it exceeds 3, it will become difficult to make molecular weight high.

In addition, it is preferable to use the raw material (a) and the raw material (b) in the range of (a) :( b) = 90: 10-10: 90 by weight ratio, and also in the range of 90: 10-30: 70. It is more preferable to use. When the weight ratio of the raw material (a) is larger than 90:10, the heat resistance of the cured coating film tends to be lowered, and when the weight ratio of the raw material (b) is larger than 10:90, the flexibility tends to be insufficient.

As an organic solvent used for reaction, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-, for example Nitrogen-containing compound solvents such as 2-pyrrolidone and tetramethyl urea, sulfur-containing compound solvents such as dimethyl sulfoxide and diethyl sulfoxide, cyclic ester compound solvents such as γ-butyrolactone, cyclohexanone and the like And ether solvents such as ketone solvents, diglyme, and triglyme; ester solvents such as carbitol acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate. You may use these solvent in mixture of 2 or more type. Moreover, you may use it, mixing suitably nonpolar solvents, such as an aromatic hydrocarbon, as needed.

The reaction may be carried out by adding a catalyst as necessary. Examples of the catalyst include tetramenalbutanediamine, benzyldimethylamine, triethanolamine, triethylamine, N, N-dimethylpiperidine, α-methylbenzyldimethylamine, and N-methyl. Tertiary amines such as morpholine and triethylenediamine, and organic metal catalysts such as dibutyltin laurate, dimethyltin dichloride, cobalt naphthenate and zinc naphthenate.

As for the number average molecular weight of component (A) in this invention, 500-100,000 are preferable. More preferably, it is 2,000-50,000. In this invention, a number average molecular weight is the value of polystyrene conversion measured by the gel permeation chromatography (GPC). As for the number average molecular weight by GPC method, Mobile phase uses GPC-101 by Showa Denko Corporation as a measuring apparatus, and Shodex KF-800RH / LF-804 by Showa Denko Corporation as a column. Tetrahydrofuran is used as the measurement, measured at a column temperature of 40 ° C., and can be calculated using a calibration curve of standard polystyrene. When the number average molecular weight of component (A) is less than 500, there exists a tendency for the softness of the cured coating film to become inadequate, and when it exceeds 100,000, the viscosity of component (A) will become high and handling will become difficult.

As for the epoxy equivalent of the component (A) in this invention, 500-25,000 are preferable. More preferably, it is 500-10,000. When the epoxy equivalent of component (A) is less than 500, the softness of a cured coating film may be impaired, and when it exceeds 25,000, it exists in the tendency for a crosslinking reaction to become inadequate. In this invention, an epoxy equivalent is the value measured according to JISK7236.

The epoxy curing agent which is the component (B) in the present invention is not particularly limited as long as it is a compound that crosslinks or polymerizes an epoxy group. Specifically, anionic polymerization catalysts such as imidazole compounds, dicyandiamide, guanamine derivatives, melamine derivatives, polybasic acid hydrazide compounds, aliphatic amine compounds, aromatic amine compounds, polythiol compounds, acid anhydride compounds, phenol novolacs, and the like And cationic polymerization catalysts such as polyfunctional phenol compounds and triphenylphosphonium hexafluoroantimonate.

Among these epoxy curing agents, acid anhydride compounds are preferred from the viewpoint of reactivity. As the acid anhydride compound, phthalic anhydride, tetrahydro phthalic anhydride, hexahydro phthalic anhydride, methyltetrahydro phthalic anhydride, methylhexahydro phthalic anhydride, methylnadic acid anhydride, hydrogenated methylnadic acid anhydride, trialkyltetrahydro phthalic anhydride, dodecenyl Succinic anhydride, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, benzo Phenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, oxydiphthalic acid dianhydride, 3,3'-4,4'-diphenylsulfontetracarboxylic dianhydride, 1,3,3a, 4 , 5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-C] furan-1,3-dione, ethylene glycolbis (anhydro Trimellitate), styrene-maleic acid copolymerized with styrene and maleic acid Polymeric acid anhydrides, such as resin, etc. are mentioned. Among these acid anhydrides, acid anhydrides having an acid anhydride group of two or more functional groups in one molecule are preferable from the viewpoint of ease of three-dimensional crosslinking reaction and reactivity, and tetrabasic dianhydride is particularly preferable.

As an epoxy curing agent which is the component (B) in this invention, when using the hardening agent which has an active hydrogen group which reacts with an epoxy, and does not react normally with a hydroxyl group, the number of epoxy groups of a component (A) (W _EP ) And the ratio of the number of active hydrogen groups reacting with the epoxy group is preferably 1: 0.2 to 1: 2. When the ratio of the number of active hydrogen groups to the number of epoxy groups is less than 0.2 or exceeds 2.0, the crosslinking reaction tends to be insufficient. Here, "it does not react normally with a hydroxyl group" means that reaction with a hydroxyl group does not occur at the temperature below the curing temperature (for example, 80-200 degreeC) at the time of hardening a resin composition. As an epoxy hardening | curing agent which has an active group which reacts with an epoxy group, and does not normally react with a hydroxyl group, Phenol compounds, such as a dicyandiamide, a guanamine derivative, a polybasic acid hydrazide compound, an aliphatic amine compound, an aromatic amine compound, and a phenol novolak Etc. can be mentioned.

As described above, the "polyurethane resin having an epoxy group and a urethane structure" of the present invention is preferably (a) a polyol compound having two or more hydroxyl groups in the molecule, and (b) one or more hydroxyl groups in the molecule. It can obtain by making the epoxy compound which has the above epoxy group, and (c) polyisocyanate compound which has 2 or more isocyanate groups in a molecule | numerator react.

As described above, when the number of hydroxyl groups of the raw material (a) is Xa and the number of hydroxyl groups of the raw material (b) is Xb and the number of isocyanate groups of the raw material (c) is Y, then (Xa + Xb Although the range whose value of) / Y becomes 1-3 is preferable, in this case, it is thought that the said polyurethane resin has a hydroxyl group.

When the molecular weight of the raw material (a) component is Ma, the hydroxyl group equivalent is Za, the molecular weight of the raw material (b) component is Mb, the hydroxyl group equivalent is Zb, the molecular weight of the raw material (c) is Mc, and the isocyanate group equivalent is Zc. The number of functional groups per molecule of each component can be calculated by the following equation. Here, the number of functional groups per molecule of the hydroxyl group of the raw material (a) is Na, the number of functional groups per molecule of the hydroxyl group of the raw material (b) is Nb, and the number of functional groups per molecule of the isocyanate group of the raw material (c) is Nc. It is called.

Na = Ma / Za

Nb = Mb / Zb

Nc = Mc / Zc

Moreover, the theoretical value of the hydroxyl group equivalent of resin which made the raw material (a), the raw material (b), and the raw material (c) react with the molar ratio of a: b: c can be computed by a following formula.

(Ma × a + Mb × b + Mc × c) / (Na × a + Nb × b-Nc × c)

When the "polyurethane resin having an epoxy group and a urethane structure" of the present invention is in a form having a hydroxyl group theoretically from the reaction ratio of the raw material as described above, from the viewpoint of promoting the crosslinking reaction, particularly as an epoxy curing agent, an epoxy group and Preference is given to using acid anhydride compounds which react with hydroxyl groups.

The compounding quantity of an acid anhydride compound can adjust a preferable quantity with the hydroxyl group derived by said calculation formula, and, with respect to the sum total of the number of hydroxyl groups (W _OH ) and the number of epoxy groups (W _EP ), an acid anhydride group It is preferable to use so that the number of may be 0.1 to 2.0. When the ratio of the number of acid anhydride groups to the sum of the number of hydroxyl groups and epoxy groups is less than 0.1 or more than 2.0, the effect in the crosslinking reaction tends not to be sufficiently obtained. Here, it is assumed that the acid anhydride group and the hydroxyl group react in an equivalent ratio of 1: 1, and likewise the acid anhydride group and the epoxy group react in an equivalent ratio of 1: 1.

As described above, in the present invention, in a form in which the "polyurethane resin having an epoxy group and a urethane structure" has a hydroxyl group, a system using an acid anhydride compound (particularly tetrabasic anhydride) as an epoxy curing agent is used for crosslinking reaction. It is preferable from a viewpoint of promoting and improving solvent resistance. In this case, the hydroxyl group equivalent of the urethane resin is preferably 250 to 50,000, and more preferably 1,000 to 25,000. When the hydroxyl group equivalent is less than 250, the flexibility of the coating film tends to be impaired. When the hydroxyl group equivalent exceeds 50,000, the effect in the crosslinking reaction is insufficient due to the decrease in reactivity with the acid anhydride compound.

The resin composition of this invention may contain the oxazoline compound of component (C) for the purpose of further improving insulation reliability. As the oxazoline compound, 2-ethyl-2-oxazoline, 2-propyl-2-oxazoline, 2-butyl-2-oxazoline, 2-octyl-2-oxazoline, 2-cyclohexyl-2-oxazoline , 2-allyl-2-oxazoline, 2-phenyl-2-oxazoline, laurylaminoethyloxazoline, dilaurylaminoethyloxazoline, lauryloxyethyloxazoline, 2,2'-bis (2-oxa Sleepy), 2,2'-ethylenebis (2-oxazoline), 2,2'-tetramethylenebis (2-oxazoline), 2,2 '-(1,3-phenylene) bis (2-oxa Sleepy), 2,2 '-(1,4-phenylene) bis (2-oxazoline), etc. are mentioned. Moreover, the compound which contains an oxazoline frame | skeleton in a polymer, such as a polyoxazoline compound which contains such an oxazoline compound as a monomeric unit, a styrene- 2-isopropenyl 2-oxazoline copolymer, etc. are mentioned. Among these oxazoline compounds, an oxazoline compound having two or more oxazoline skeletons is preferable from the viewpoint of crosslinking reaction, and a bisoxazoline compound is preferable from the viewpoint of reactivity. Among them, 2,2 '-(1,3-phenylene) bis (2-oxazoline) (hereinafter abbreviated as 1,3-PBO) is particularly preferable. As for the compounding quantity of an oxazoline compound, the ratio of the oxazoline group with respect to an acid anhydride group is preferably 0.05-3.0. More preferably, it is 0.1-2.0. If it is less than 0.05 molar equivalent, the effect which added the oxazoline compound is small, and when it exceeds 3.0, insulation reliability may fall rather.

The resin composition of this invention may use together the hardening accelerator which accelerates the hardening reaction of an epoxy hardening | curing agent as needed. Examples of the curing accelerator include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, 1,8-diazabicyclo- [5.4.0] -7-undecene ( DBU), metal salts, such as 2-ethylhexanoate of zinc, octylic acid zinc, and octylic acid tin, urea compounds, such as phenyldimethyl urea, toluenebisdimethyl urea, and methylenediphenyldimethyl urea, etc. are mentioned.

Various resin additives can be mix | blended with the resin composition of this invention in the range in which the effect of this invention is exhibited. As the resin additive, silica, alumina, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate Inorganic fillers such as bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, organic rubbers such as acrylic rubber particles, polyamide fine particles and silicon particles, silane coupling agents, titanate coupling agents, aluminum coupling agents, and the like. Defoamers such as coupling agents, silicone defoamers, fluorine defoamers, acrylic polymer defoamers, inorganic pigments such as titanium oxide and zinc oxide, organic compounds such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow and carbon black. Coloring agents such as pigments and organic dyes, hindered phenol compounds, phosphorus compounds, sulfur compounds, UV light absorbers such as antioxidants such as drazide compounds, benzotriazole compounds, hindered amine compounds, flame retardants such as phosphorus compounds, aluminum hydroxide and magnesium hydroxide, leveling agents, thixotropic agents, 2,4,6- Adhesion promoters such as trimercapto-s-triazole, 2,5-dimercapto-1,3,4-thiadiazole, and the like.

The resin composition of this invention can be prepared by melt | dissolving or disperse | distributing the compounding component containing (A) epoxy group containing urethane resin and (B) epoxy hardening | curing agent using a planetary mixer, three rolls, a bead mill, etc. In preparation, you may use the organic solvent for viscosity adjustment as needed. The organic solvent used for viscosity adjustment can use the same thing as the organic solvent used for said reaction. When using for overcoat of a flexible printed wiring board, it is normally prepared as a paste-like resin composition.

By apply | coating the paste-form resin composition of this invention to the predetermined part of a flexible printed wiring board and drying an application | coating surface, the flexible printed wiring board in which the whole surface or one part surface was protected by the resin composition of this invention can be obtained. Drying conditions can be suitably easily set by a person skilled in the art according to the kind of paste resin composition to be used, Usually, it is made to dry at 100-200 degreeC for about 1 to 120 minutes. Although the thickness of the surface protection film formed is not specifically limited, either, Usually, it is 5-100 micrometers. There is no restriction | limiting in particular in the flexible printed wiring board whose surface is protected by the resin composition of this invention, Flexible printed wiring board for TAB (Tape Automated Bonding), Flexible printed wiring board for COF, Multilayer flexible printed wiring board, Flexible paste printed flexible printed wiring board, etc. Although various flexible printed wiring boards can be used, the resin composition of this invention can be used suitably especially for overcoat of a flexible printed wiring board for TAB, and a flexible printed wiring board for COF.

The flexible printed wiring board whose surface was protected by the resin composition of this invention can be used in the form incorporated in various electronic devices. For example, mobile phones, digital cameras, video cameras, game equipment, PCs, printers, hard disk drives, plasma televisions, liquid crystal televisions, liquid crystal displays, car navigation systems, copiers, fax machines, AV equipment, measuring equipment, medical equipment, etc. It is suitably used as internal wiring of various electronic devices.

Hereinafter, although an Example is shown and this invention is demonstrated concretely, this invention is not limited to this. In an example, a part means a mass part. In addition, the hydroxyl group equivalent of the hydroxyl group containing epoxy resin of the synthesis example 1, and the epoxy group containing urethane resin of the synthesis examples 2-6 was calculated | required by calculation. Regarding Synthesis Example 1, the phenolic hydroxyl group of bisphenol A to react with epoxy resin (HP-7200) and equimolar hydroxyl group are produced, and to Epicoat 1001 used in Synthesis Examples 2 to 6 Regarding this, two epoxy groups were used in one molecule, and the molecular weight was considered to be twice the epoxy equivalent from the actual value of the premise and the epoxy equivalent, and the number of hydroxyl groups in one molecule was obtained from the following equation.

Number of hydroxyl groups in 1 molecule = (molecular weight-57) / (228 + 58))-1

Here, "57" is the molecular weight of the glycidyl ether group, "228" is the molecular weight of bisphenol A, "58" is the secondary hydroxyl group structure produced when the glycidyl ether structure and the phenol group of bisphenol A react. The molecular weight of the compound having

<Synthesis example 1> Synthesis of hydroxyl group-containing epoxy resin (E-1)

291.4 g of dicyclopentadiene type epoxy resin HP-7200 (made by Dainippon Ink & Chemicals Co., Ltd., epoxy equivalent 260) in 500 ml flask equipped with a stirring apparatus, a thermometer, and a condenser, bisphenol A (Mitsui Chemical Co., Ltd.) Preparation) 55.6 g, 150.0 g of ethyl diglycol acetate was injected as a solvent, and it heated at 70 degreeC under nitrogen stream, and obtained the uniform solution. After adding 2.9 g of triphenylphosphine to it, it heated up at 120 degreeC and reacted for 5 hours as it was, and obtained hydroxyl group containing epoxy resin E-1.

Properties of the hydroxyl group-containing epoxy resin E-1:

Viscosity 74 Pa.s (25 ° C, E-type viscometer)

70% solids

Number average molecular weight 1,700 (GPC, polystyrene equivalent)

Epoxy equivalent 538

Hydroxyl group equivalents 711

Synthesis Example 2 Synthesis of Epoxy Group-Containing Urethane Resin (EU-1)

185.5 g of polycarbonate diol T-6001 (made by Asahi Chemical Co., Ltd., hydroxyl value 115 mgKOH / g) in the 500 ml flask provided with the stirring apparatus, the thermometer, and the condenser, and the hydroxyl group shown in <synthesis example 1>. 188.8 g of epoxy resin E-1 and 90.0 g of γ-butyrolactone were injected, and 32.3 g of 2,4-trilene diisocyanate and ifsol # 150 of dibutyltin dilaurate were stirred at room temperature under a stream of nitrogen ( 3.5 g of a 1% solution of Idemitsukosan Co., Ltd.) was added, and the temperature of the product (temperature of the mixture) was raised to 80 ° C and allowed to react for 3 hours. Infrared spectroscopy confirmed that the absorption based on the isocyanate group was lost, and the reaction was terminated to obtain an epoxy group-containing urethane resin EU-1.

Properties of Epoxy Group-containing Urethane Resin EU-1

Viscosity 107 Pa · s (25 ° C, E-type viscometer)

70% solids

Number average molecular weight 4,100 (GPC, polystyrene equivalent)

Epoxy equivalent 1,411

Hydroxyl group equivalents 1,476

Synthesis Example 3 Synthesis of Epoxy Group-Containing Urethane Resin (EU-2)

Polycarbonate diol T-6001 (manufactured by Asahi Chemical Co., Ltd., 115 mgKOH / g of hydroxyl group value 115 mgKOH / g) in a 500 ml flask equipped with a stirring device, a thermometer, and a condenser, epicoat 1001 (as a hydroxyl group-containing epoxy resin) Japan Epoxy Resin Co., Ltd., 41.9 g of epoxy equivalent 475), γ-butyrolactone 88.0 g, and 2.1 g of 1% solution of Ipsol # 150 (manufactured by Idemitsukosan Co., Ltd.) of dibutyltin dilaurate are injected. And 33.7 g of 4,4'- diphenylmethane diisocyanate was added little by little so that product temperature might not exceed 80 degreeC, stirring at room temperature under nitrogen stream. After adding the whole amount of 4,4'- diphenylmethane diisocyanate, the product temperature was heated up to 80 degreeC and made to react for 1 hour. Infrared spectroscopy confirmed that absorption based on the isocyanate group was lost, and the reaction was terminated to obtain an epoxy group-containing urethane resin EU-2.

Properties of Epoxy Group-containing Urethane Resin EU-2

Viscosity 239 Pa.s (25 ° C, E-type viscometer)

70% solids

Number average molecular weight 5,326 (GPC, polystyrene equivalent)

Epoxy equivalent 2,199

Hydroxyl group equivalent 2,085

Synthesis Example 4 Synthesis of Epoxy Group-Containing Urethane Resin (EU-3)

Polycarbonate diol UM-CARB90 (1/3) (manufactured by Ubeko Co., Ltd., diol component of 1,4-cyclohexanedimethanol / 1,6-hexanediol) in a 500 ml flask equipped with a stirring device, a thermometer, and a condenser. Copolymer carbonate diol contained in 1/3, hydroxyl group value 126mgKOH / g) 114.2g, 58.0 g of epicoat 1001 (Japan Epoxy Resin Co., Ltd., epoxy equivalent 475) as a hydroxyl group containing epoxy resin, gamma-buty 18.0 ml of 2,4-trilene diisocyanate, ifsol # 150 (manufactured by Idemitsukosan Co., Ltd.) of 2,4-trilene diisocyanate and dibutyltin dilaurate while injecting 198.0 g of rockactone and stirring at room temperature under a stream of nitrogen. g was added, the product temperature was raised to 80 ° C. and reacted for 3 hours. Infrared spectroscopy confirmed that the absorption based on the isocyanate group was lost, and the reaction was terminated to obtain an epoxy group-containing urethane resin EU-3.

Properties of Epoxy Group-Containing Urethane Resin EU-3

Viscosity 65 Pa.s (25 ° C, E-type viscometer)

50% solids

Number average molecular weight 8,034 (GPC, polystyrene equivalent)

Epoxy Equivalent 1,443

Hydroxyl group equivalents 2,928

Synthesis Example 5 Synthesis of Epoxy Group-Containing Urethane Resin (EU-4)

Polycarbonate diol UM-CARB90 (1/1) (manufactured by Ubeko Co., Ltd., diol component of 1,4-cyclohexanedimethanol / 1,6-hexanediol) in a 500 ml flask equipped with a stirring device, a thermometer, and a condenser. Copolymer carbonate diol, hydroxyl group value 124mgKOH / g) 170.1g, and polybutadiene diol G-1000 (manufactured by Nippon Soda Co., Ltd., hydroxyl value 72mgKOH / g) 15.3g, hydroxyl group contained in 1/1 As the containing epoxy resin, 58.0 g of Epicoat 1001 (Japan Epoxy Resin Co., Ltd., Epoxy equivalent 475) and 117.2 g of ethyl diglycol acetate were charged, and 2,4-trilene was stirred at room temperature under a nitrogen stream. 34.5 g of diisocyanate and 2.8 g of 1% solution of IFZOL # 150 (manufactured by Idemitsukosan Co., Ltd.) of dibutyltin dilaurate were added, and the temperature of the product was raised to 80 ° C and allowed to react for 3 hours. Infrared spectroscopy confirmed that the absorption based on the isocyanate group was lost, the reaction was terminated, and an epoxy group-containing urethane resin EU-4 was obtained.

Properties of Epoxy Group-containing Urethane Resin EU-4

Viscosity 267 Pa.s (25 ° C, E-type viscometer)

70% solids

Number average molecular weight 7,723 (GPC, polystyrene equivalent)

Epoxy equivalent 2,028

Hydroxyl group equivalents 2,139

<Synthesis example 6> Synthesis of urethane resin (U-1) containing no epoxy group

Into a 500 ml flask equipped with a stirring device, a thermometer, and a condenser, 329.1 g of polycarbonate diol T-6001 (manufactured by Asahi Chemical Co., Ltd., hydroxyl value 115 mgKOH / g) and 121.7 g of γ-butyrolactone were injected. 45.9 g of 2,4-trilene diisocyanate and 3.3 g of 1% solution of Ipsol # 150 (manufactured by Idemitsukosan Co., Ltd.) of dibutyltin dilaurate were added while stirring at room temperature under a nitrogen stream, and the temperature was 80 ° C. It was heated up and reacted for 3 hours. Infrared spectroscopy confirmed that absorption based on the isocyanate group was lost, and the reaction was terminated to obtain an epoxy group-containing urethane resin U-1.

Properties of Urethane Resin U-1 without Epoxy Group

Viscosity 185 Pa.s (25 ° C, E-type viscometer)

75% solids

Number average molecular weight 8,600 (GPC, polystyrene equivalent)

Hydroxyl Group Equivalent 2,541

Example 1

The epoxy group-containing urethane resin solution (EU-1) obtained in Synthesis Example 2 was converted into solids as 40.0 g, tetrabasic acid anhydride, and B-4400 (manufactured by Dainippon Ink Chemical Co., Ltd., acid anhydride equivalent 132) 2.91 g, triphenylphosphine (manufactured by Junsegawa Chemical Co., Ltd.) 0.21 g, and 0.8 g of hydrophilic fumed silica A-380 (manufactured by Nippon Aerosol Co., Ltd.) as an inorganic filler were mixed and kneaded with three roll mills. Then, gamma -butyrolactone was added, the viscosity was adjusted to about 20-40 Pa.s, and the thermosetting resin composition was prepared.

Example 2

As a bisoxazoline compound, 3.44g of 1,3-PBO (made by Mikuni Seyaku Kogyo Co., Ltd., oxazoline group equivalent 108) is newly added, except 3.64g of B-4400 and 0.24g of triphenylphosphine. In the same manner as in Example 1, a thermosetting resin composition was prepared.

Example 3

The epoxy group-containing urethane resin solution (EU-2) obtained in Synthesis Example 3 was converted to 40.0 g in terms of solid content, except that 2.22 g for 1,3-PBO, 2.26 g for B-4400, and 0.22 g for triphenylphosphine. In the same manner as in Example 2, a thermosetting resin composition was prepared.

Example 4

The epoxy group-containing urethane resin solution (EU-3) obtained in Synthesis Example 4 was converted to 40.0 g in terms of solid content, except that 2.07 g for 1,3-PBO, 2.70 g for B-4400, and 0.23 g for triphenylphosphine. In the same manner as in Example 2, a thermosetting resin composition was prepared.

Example 5

The epoxy group-containing urethane resin solution (EU-4) obtained in Synthesis Example 5 was converted to 40.0 g in terms of solid content, except that 3.24 g for 1,3-PBO, 2.64 g for B-4400, and 0.23 g for triphenylphosphine. In the same manner as in Example 2, a thermosetting resin composition was prepared.

&Lt; Reference Example 1 &

45.8g of solid-state urethane resin solution (U-1) obtained in the synthesis example 6 was converted into solid content, and HP-7200 (made by Dainippon Ink & Chemical Co., Ltd., epoxy equivalent 260) was newly added as an epoxy resin. A thermosetting resin composition was prepared in the same manner as in Example 1 except that 4.18 g, 2.13 g of B-4400, 0.22 g of triphenylphosphine, and 1.00 g of A-380 were prepared.

Reference Example 2

The urethane resin solution (U-1) which does not contain the epoxy group obtained by the synthesis example 6 is 35.0g in terms of solid content, 15.0g for HP-7200, 7.62g for B-4400, and 0.29g for triphenylphosphine. A thermosetting resin composition was prepared in the same manner as in Reference Example 1 except for the above.

Reference Example 3

A thermosetting resin composition was prepared in the same manner as in Reference Example 2 except that 1.99 g of 1,3-PBO was newly added as a bisoxazolin compound, 9.24 g of B-4400 and 0.31 g of triphenylphosphine.

<< evaluation as an overcoat agent which protects the electronic circuit surface of a flexible printed circuit board >>

<Evaluation of solvent resistance>

The thermosetting resin composition prepared in the Examples and Reference Examples was screen printed using a 200 mesh plate on a 50 μm thick polyimide film (Yuprex 50S: manufactured by Ubekosan Co., Ltd.), at 120 ° C. for 1 hour, and also at 150 ° C. Curing for 2 hours. The hardened surface was rubbed with a force of 400 to 500 g using a cotton swab impregnated with acetone, and the surface was scratched and the color was missing, and the surface was melted and exposed to the substrate. . The results are shown in Table 1.

<Flexibility Evaluation>

The thermosetting resin composition prepared in the Examples and Reference Examples was screen printed using a 200 mesh plate on a 50 μm thick polyimide film (Yuprex 50S: manufactured by Ubekosan Co., Ltd.), at 120 ° C. for 1 hour, and also at 150 ° C. Curing for 2 hours. The printed surface of the polyimide film was folded outward with 180 degrees. (Circle) and that which whitening or a crack were observed in the cured film were made into x that the whitening does not arise in a cured film. The results are shown in Table 1.

<Warping evaluation>

The thermosetting resin composition prepared in Examples and Reference Examples was screen printed on a 50 μm-thick polyimide film (Yuprex 50S manufactured by Ubekosan Co., Ltd.) using 200 mesh and a plate of 10 cm × 10 cm size, and then subjected to screen printing at 120 ° C. After curing for 4 hours, 4 pieces were cut out to a size of 5 cm x 5 cm. Furthermore, these were further hardened | cured at 150 degreeC for 2 hours as a test piece. The hardening caused the test piece to bend in the form in which the printing surface was concave. The four test pieces were placed on the smooth glass plate with the printing surface facing up, and the magnitude of the rise from the glass plate at the position of the one of the largest bends in each test piece was measured, and the average value of the four pieces was calculated. The results are shown in Table 1.

<Evaluation of Electrical Insulation Reliability>

The thermosetting resin composition prepared in the Examples and Reference Examples was used on a polyimide substrate having a comb-shaped electrode pattern with a 30 μm pitch, using a 200 mesh plate, and L / S = 15/15 μm on a polyimide film having a thickness of 37.5 μm. The polyimide substrate with the comb-shaped electrode pattern having a thickness of 8 µm was screen printed so as to cover the entire surface of the comb-shaped electrode pattern, and cured at 120 ° C for 1 hour and at 150 ° C for 2 hours. It was left to stand in 120 degreeC and the atmosphere of 85% of a relative humidity, applying a voltage of 60V here. The holding time until ionic migration or lowering of the insulation resistance value (up to 10 ⁶ Ω or less) was observed, and this was referred to as the HAST (Highly Accelerated temperature and humidity Stress Test) endurance time. The results are shown in Table 1.

As can be seen from Table 1, in the embodiment of the present invention, the resin composition for overcoat of the flexible printed wiring board containing (A) an epoxy group and a polyurethane resin having a urethane structure and (B) an epoxy curing agent is Comparative Example 1 Compared with the 3 to 3, the warpage of the printed wiring board was greatly reduced. (C) Examples 2-5 ”which further contain an oxazoline compound showed the further curvature at the same time, and were excellent also in electrical insulation reliability. Thus, the thermosetting resin composition of this invention is excellent in solvent resistance and bendability, and both the bending property and the electrical insulation reliability are achieved.

This application is based on Japanese Patent Application No. 2007-271600 filed in Japan, and includes all its contents in this specification.

Claims (16)

The resin composition for overcoat of the flexible printed wiring board containing the polyurethane resin which has (A) epoxy group and urethane structure, and (B) epoxy hardening | curing agent. The resin composition according to claim 1, wherein the polyurethane resin further has at least one structure selected from polycarbonate structures, polydiene structures, polyester structures, and polyether structures. The resin composition of Claim 1 in which a polyurethane resin further has a polycarbonate structure and / or a polydiene structure. The resin composition of Claim 1 in which a polyurethane resin further has a polycarbonate structure. The polyurethane resin according to any one of claims 1 to 4, wherein the polyurethane resin has (a) a polyol compound having two or more hydroxyl groups in the molecule, and (b) one or more hydroxyl groups and one or more epoxy groups in the molecule. A resin composition, which is a polyurethane resin obtained by reacting an epoxy compound and (c) a polyisocyanate compound having two or more isocyanate groups in a molecule. The resin composition according to claim 5, wherein the polyol compound is at least one polyol compound selected from polycarbonate polyols, polydiene polyols, polyester polyols, and polyether polyols. The resin composition of Claim 5 whose polyol compound is a polycarbonate polyol and / or a polydiene polyol. The resin composition of Claim 5 whose polyol compound is a polycarbonate polyol. The resin composition as described in any one of Claims 1-8 whose (B) epoxy hardening | curing agent is an acid anhydride compound. (B) The resin composition of any one of Claims 1-8 whose epoxy hardening | curing agent is tetrabasic dianhydride. The resin composition according to any one of claims 1 to 10, further comprising (C) an oxazoline compound. The resin composition of Claim 11 whose (C) oxazoline compound is a bisoxazoline compound. The resin composition according to any one of claims 1 to 12, wherein the resin composition is a pasty resin composition. The resin composition according to any one of claims 1 to 13, further comprising a curing accelerator. The flexible printed wiring board whose surface was protected by the hardened | cured material of the resin composition of any one of Claims 1-14. An electronic device containing the flexible printed wiring board according to claim 15.