TWI453253B - Resin composition - Google Patents

Description

Resin composition

The present invention relates to a useful resin composition as a cover material for protecting an electronic circuit surface of a flexible printed circuit board, a flexible printed circuit board having a cured surface protected by the resin composition, and a flexible printed circuit therewith Electronic machine for the board.

Flexible printed circuit boards (FPC) utilized by TCP (Tape Carrier Package) and COF (Chip On Flexible or Film), generally, on one or both sides of polyester terephthalate and polyimide films. It is mainly composed of a substrate having a conductor layer (conductor circuit layer) forming a circuit, and a surface protective film protecting the surface of the substrate. Insulating protective film for FPC, generally, a method of punching a polyimide film into a desired shape and providing a cover film of an adhesive layer, attaching to a substrate, and a varnish-like resin composition (covering agent) A method of printing into a desired pattern by screen printing and hardening it. The method of using a cover film is disadvantageous in terms of workability and cost, so that a method of coating a cover film by screen printing has become mainstream. A coating composition for a flexible printed circuit board, for example, a composition comprising an epoxy resin, an imidazole compound, and a long-chain dibasic acid anhydride is disclosed in Japanese Patent Publication No. Hei 5-75032.

A coating material for a flexible printed circuit board is required to satisfy both solvent resistance, flexibility (bending property), low bendability, and electrical insulating properties. Accordingly, the present invention is directed to a resin composition which is excellent in providing such a property as a coating agent for a flexible printed circuit board.

In order to solve the above problems, the inventors of the present invention have found that a resin composition containing a polyurethane resin having an epoxy group and a urethane structure and an epoxy curing agent is excellent in the above characteristics. Moreover, it can be used as an excellent resin composition for covering a flexible printed circuit board, and the present invention has been completed. That is, the present invention encompasses the following.

[1] A resin composition for covering a flexible printed circuit board, comprising (A) a polyurethane resin having an epoxy group and a urethane structure, and (B) an epoxy resin; hardener.

[2] The resin composition according to the above [1], wherein the polyurethane resin further has one or more structures selected from the group consisting of a polycarbonate structure, a polydiene structure, a polyester structure, and a polyether structure.

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

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

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

[6] The resin composition according to the above [5], wherein the polyol compound is one or more selected from the group consisting of a polycarbonate polyol, a polydiene polyol, a polyester polyol, and a polyether polyol. .

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

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

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

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

[11] The resin composition according to any one of [1] to [10] further comprising (C) Oxazoline compound.

[12] The resin composition according to [11] above, wherein (C) Oxazoline compound is double Oxazoline compound.

[13] The resin composition according to any one of [1] to [12] wherein the resin composition is a paste resin composition.

[14] The resin composition according to any one of [1] to [13] further comprising a curing accelerator.

[15] A flexible printed circuit board characterized by the cured surface of the resin composition according to any one of the above [1] to [14].

[16] An electronic device comprising the flexible printed circuit board according to [15] above.

[17] A resin composition comprising (A) a polyurethane resin having an epoxy group and a urethane structure, (B) an epoxy hardener, and (c) Oxazoline compound.

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

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

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

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

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

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

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

[25] The resin composition according to any one of [17] to [24] wherein Oxazoline compound is double Oxazoline compound.

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

The resin composition of the present invention is excellent in solvent resistance, flexibility (bending property), low bendability, and electrical insulation, and can be used as an excellent resin composition for covering a flexible printed circuit board.

The "polyurethane resin having an epoxy group and a urethane structure" of the component (A) in the present invention further has a polycarbonate structure and a polycondensation from the viewpoint of sufficiently exhibiting the effects of the present invention. A diene structure, a polyester structure or a polyether structure is preferred. Among these structures, a polycarbonate structure and a polybutadiene structure are preferred, and a polycarbonate structure is particularly preferred. In one molecule of the polyurethane resin having an epoxy group and a urethane structure, two or more of these structures may be contained at the same time.

The "polyurethane resin having an epoxy group and a urethane structure" preferably has, for example, a polyol compound having (a) two or more hydroxyl groups in the molecule, and (b) one molecule in the molecule. The above hydroxyl group can be obtained by reacting an epoxy compound having one or more epoxy groups and (c) a polyisocyanate compound having two or more isocyanate groups in the molecule.

Examples of the polyol compound having two or more hydroxyl groups in the molecule of the raw material (a) include a polycarbonate polyol, a polydiene polyol, a polyester polyol, and a polyether polyol.

Examples of the polyester polyol include an adipate-based polyol such as a polyethylene adipate polyol or a polybutylene adipate polyol, and a p-citric acid-based polyol or a polybutyrolactone polyol. Two or more types of polyol compounds may be used in combination.

Examples of the polyether polyol include polypropylene glycol, polybutylene glycol, and polyvinyl ether polyol. Examples of the polyvinyl ether polyol include TOE-2000H (manufactured by Kyowa Chemical Co., Ltd.).

The polydiene polyol may, for example, be a polybutadiene polyol or a polyisoprene polyol. As the polydiene polyol, a hydrogenated polydiene polyol such as a hydrogenated polybutadiene polyol or a hydrogenated polyisoprene polyol can also be used. The polybutadiene polyol may be exemplified by a 1,4-bonded hydroxyl terminal liquid polybutadiene Poly bd R-45HT, R-15HT (manufactured by Idemitsu Kosan Co., Ltd.), and a hydroxyl terminated polybutadiene. Hydrogenated Polytail H, Polytail HA (manufactured by Mitsubishi Chemical Corporation), terminal hydroxylated polybutadiene G-1000, G-2000, G-3000 mainly having 1,2-bonding (above Japanese Soda ( (Production), the above-mentioned oxides GI-1000, GI-2000, GI-3000 (manufactured by Japan Soda Co., Ltd.) which mainly have a 1,2-bonded terminal hydroxylated polybutadiene resin. Examples of the polyisoprene polyol include a hydroxyl terminal liquid isoprene Poly ip, Epol (manufactured by Idemitsu Kosan Co., Ltd.), and the like.

The polycarbonate polyol includes a polycarbonate polyol containing one or two or more kinds of repeating units of a polyhydric alcohol such as a linear aliphatic diol, an alicyclic diol or a glycerin. The linear aliphatic diol may, for example, be 1,6-hexanediol, 1,5-pentanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,9- Decylene glycol, 2-methyl-1,8-octanediol, and the like. The alicyclic diol is exemplified by 1,4-cyclohexanedimethanol.

Among these polyols, polybutadiene polyols and polycarbonate polyols are preferred from the viewpoint of water resistance, heat resistance and flexibility, and polycarbonate polyols are particularly preferred. The polybutadiene polyol is particularly preferably a polybutadiene diol, and the polycarbonate polyol is particularly preferably a polycarbonate diol.

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

The epoxy group compound having one or more hydroxyl groups and one or more epoxy groups in the molecule of the raw material (b) includes one or more hydroxyl groups in the molecule, a glycidyl ether structure, a glycidyl ester structure, and a glycidylamine structure. An epoxy compound in which one or more epoxy groups are selected from the alicyclic epoxy structure and the oxirane ring structure. In the epoxy compound having one or more hydroxyl groups and one or more condensed glyceryl ether structures in the molecule, Epicoat 1001, Epicoat 1004 (manufactured by Japan Epoxy Resin Co., Ltd.), etc., and one or more molecules are included in the molecule. The epoxy compound having a hydroxyl group and one or more oxirane ring structures may be exemplified by a hydroxyl terminated epoxidized polybutadiene PB-3600 (Diacel Chemical Industry Co., Ltd.).

(b) an epoxy compound having one or more hydroxyl groups and one or more epoxy groups in the molecule, and (e) an epoxy compound having two or more epoxy groups in the molecule (d) and (e) one molecule in the molecule The above reaction with the active hydrogen group-reactive compound of the epoxy group can also be obtained.

Examples of the epoxy compound having two or more epoxy groups in the molecule of the raw material (d) include a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, and a hydrogenated bisphenol A type ring. Oxygen resin, hydrogenated bisphenol F type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, dicyclopentadiene type epoxy resin, alkyl phenol novolac type epoxy resin, double Phenolic epoxy resin, naphthalene epoxy resin, epoxide of phenol and condensate of phenolic hydroxyl aromatic aldehyde, triglycidyl isocyanurate, alicyclic epoxy resin, glycidylamine resin An epoxy resin such as a glycidyl ester resin, a diglycidyl ether of an aliphatic diol, or a diglycidyl ether of an alicyclic diol. These epoxy compounds may be used in combination of two or more kinds.

The compound having one or more active hydrogen groups reactive with an epoxy group in the molecule of the raw material (e) may, for example, be a compound having one or more phenolic hydroxyl groups, a compound having one or more carboxyl groups, or the like. In the case of a compound having three or more active hydrogen groups, the compound (e) is preferably one having two or more active hydrogen groups because of the possibility of gelation in the reaction with the epoxy compound. Examples of the compound having one active hydrogen group include a phenol compound, a sulfur phenol compound, and a carboxylic acid compound. Examples of the compound having two active hydrogen groups include bisphenol A, bisphenol F, bisphenol S, bisphenol, hydroquinone, adipic acid, sebacic acid, dodecanedioic acid, and 8,12-eicosane. Aenedioic acid, behenic acid, and the like. These compounds may be used in combination of two or more kinds.

The raw materials (d) and (e) can be reacted at a reaction temperature of 80 ° C to 180 ° C, usually in the range of 1 hour to 8 hours. In the reaction, an organic solvent may be added as needed, and if necessary, a catalyst may be added to carry out the reaction. Examples of the catalyst include a nitrogen compound and a phosphorus compound.

Examples of the polyisocyanate compound having two or more isocyanate groups in the molecule of the raw material (c) include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and diphenylmethane. Diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate, xylene diisocyanate, hydrogenated xylene diisocyanate, butyl dimethyl diisocyanate, trimethyl hexyl diisocyanate, ornidyl diisocyanate, and the like. These isocyanate compounds may be used in combination of two or more kinds.

The reaction conditions of the raw materials (a), (b), and (c) are, for example, in the organic solvent, the reaction temperature is 15 ° C to 120 ° C, and the reaction time is usually in the range of 1 to 8 hours. Further, a catalyst may be added to carry out the reaction as needed.

The reaction ratio of the raw materials (a), (b), and (c) is regarded as the number of hydroxyl groups of the raw material (a) as Xa, the number of hydroxyl groups of the raw material (b) is regarded as Xb, and the number of isocyanate groups of the raw material (c) is regarded as Y, the range of (Xa+Xb)/Y is preferably from 1 to 3, and more preferably from 1.01 to 2. When the ratio is less than 1.0, the isocyanate group reacts in an excessive state, and it is difficult to control the molecular weight. When it exceeds 3, it tends to be difficult to increase the molecular weight.

Further, the raw material (a) and the raw material (b) are preferably used in the range of weight ratio (a):(b)=90:10 to 10:90, and more preferably in the range of 90:10 to 30:70. Better. When the weight ratio of the raw material (a) is more than 90:10, the heat resistance of the cured coating film tends to decrease, and when the weight ratio of the raw material (b) is more than 10:90, the flexibility tends to be insufficient.

The organic solvent to be used in the reaction may, for example, be N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethyl. a solvent containing a nitrogen-containing compound such as acetamide, N-methyl-2-pyrrolidone or tetramethylurea, a sulfur-containing compound solvent such as dimethyl hydrazine or diethyl hydrazine, γ-butyrolactone, or the like The cyclic ester compound is a solvent, a ketone solvent such as cyclohexanone, an ether solvent such as Diglyme or Triglyme, an ester solvent such as carbitol acetate, propylene glycol monomethyl ether acetate or propylene glycol monoethyl ether acetate. Polar solvent. These solvents may be used in combination of two or more kinds. Further, a nonpolar solvent such as an aromatic hydrocarbon may be appropriately mixed as needed.

The reaction is carried out by adding a catalyst as needed. Examples of the catalyst include tetramethylbutanediamine, benzyldimethylamine, triethanolamine, triethylamine, N,N-dimethylpiperidine, and α-methylbenzyl. Tertiary amines such as dimethylamine, N-methylmorpholine, tri-ethylidene diamine, and dibutyltin laurate, dimethyltin dichloride, cobalt naphthenate, zinc naphthenate, etc. Metal catalysts, etc.

The component (A) in the present invention preferably has a number average molecular weight of 500 to 100,000. More preferably 2,000 to 50,000. In the present invention, the number average molecular weight is a polystyrene equivalent enthalpy measured by gel permeation chromatography (GPC). In the number average molecular weight of the GPC method, specifically, GPC-101 manufactured by Showa Denko Co., Ltd. is used as a measuring device, and Shodex KF-800RH/LF-804 manufactured by Showa Denko Co., Ltd. is used as a column and tetrahydrofuran is used as a mobile phase. The column temperature was measured at 40 ° C and was calculated using a standard polystyrene calibration curve. When the number average molecular weight of the component (A) is less than 500, the flexibility of the cured coating film tends to be insufficient, and when it exceeds 100,000, the viscosity of the component (A) becomes high, which tends to be difficult to handle.

The epoxy equivalent of the component (A) in the present invention is preferably from 500 to 25,000. More preferably 500~10,000. When the epoxy equivalent of the component (A) is less than 500, the flexibility of the cured coating film is impaired, and if it exceeds 25,000, the crosslinking reaction tends to be insufficient. In the present invention, the epoxy equivalent is oxime measured in accordance with JIS K7236.

The epoxy curing agent of the component (B) in the present invention is not particularly limited as long as it is a compound which crosslinks or polymerizes an epoxy group. Specific examples thereof include an anionic polymerization catalyst such as an imidazole compound, dicyandiamide, a decylamine derivative, a melamine derivative, a polybasic acid hydrazine compound, an aliphatic amine compound, an aromatic amine compound, and a polythiol compound. A polyfunctional phenol compound such as an acid anhydride compound or a phenol novolak or a cationic polymerization catalyst such as diphenylphosphonium hexafluoroantimonate.

Among these epoxy curing agents, an acid anhydride compound is preferred from the viewpoint of reactivity. Examples of the acid anhydride compound include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl Nadic anhydride, hydrogenated methyl Nadic anhydride, and trialkyltetrahydrofurfuric anhydride. Dodecenyl succinic anhydride, 5-(2,5-dioxytetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, homo benzene Tetracarboxylic anhydride, benzophenone tetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, oxydicarboxylic acid dianhydride, 3,3'-4,4'-diphenylanthracene Tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxy-3-furanyl)-naphtho[1,2-C] A polymer type acid anhydride such as furan-1,3-dione, ethylene glycol bis(hydrogen trimellitate), styrene-maleic acid copolymer or the like, and the like. Among these acid anhydrides, the acid anhydride group is preferably a difunctional or higher acid anhydride in one molecule from the viewpoint of easiness of the three-dimensional crosslinking reaction and reactivity, and particularly preferably a tetrabasic acid dianhydride.

In the epoxy curing agent of the component (B) of the present invention, when a curing agent having an active hydrogen group reactive with an epoxy and which does not normally react with a hydroxyl group is used, the epoxy group number (W _EP ) of the component (A), and The ratio of the number of active hydrogen groups in the epoxy group reaction is preferably from 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 more than 2.0, the crosslinking reaction tends to be insufficient. Here, the phrase "generally does not react with a hydroxyl group" means that the reaction with a hydroxyl group is not caused at a temperature lower than the curing temperature (for example, 80 to 200 ° C) at the time of curing the resin composition. Examples of the epoxy hardener having an active group reactive with an epoxy group and generally not reacting with a hydroxyl group include dicyandiamide, a decylamine derivative, a polybasic acid hydrazine compound, an aliphatic amine compound, an aromatic amine compound, and phenol. a phenolic compound such as a novolak or the like.

The "polyurethane resin having an epoxy group and a urethane structure" according to the present invention is preferably a polyol compound having (a) two or more hydroxyl groups in the molecule, and (b) The epoxy compound having one or more hydroxyl groups and one or more epoxy groups in the molecule and (c) a polyisocyanate compound having two or more isocyanate groups in the molecule are reacted.

Further, as described above, when the number of hydroxyl groups of the raw material (a) is regarded as Xa, the number of hydroxyl groups of the raw material (b) is regarded as Xb, and the number of isocyanate groups of the starting material (c) is regarded as Y, then (Xa+Xb)/Y is The range of 1 to 3 is preferable, and in this case, the polyurethane resin is considered to have a hydroxyl group.

When the molecular weight of the raw material (a) is regarded as Ma, the hydroxyl equivalent is regarded as Za, the molecular weight of the raw material (b) is regarded as Mb, the hydroxyl equivalent is regarded as Zb, and the molecular weight of the raw material (c) is regarded as Mc or isocyanate equivalent. Zc, the number of functional groups per molecule per molecule can be calculated by the following formula. Here, the number of functional groups per one molecule of the hydroxyl group of the starting material (a) is regarded as Na, the number of functional groups per one molecule of the hydroxyl group of the raw material (b) is regarded as Nb, and the isocyanate group of the starting material (c) is regarded as the number of functional groups per molecule. Nc.

Nz=Ma/Za

Nb=Mb/Zb

Nc=Mc/Zc

Further, the raw material (a), the raw material (b), and the raw material (c) are theoretically calculated from the hydroxyl equivalent of the resin of the molar ratio of a:b:c, and can be calculated according to the following formula.

(Ma×a+Mb×b+Mc×c)/(Na×a+Nb×b-Nc×c)

The "polyurethane resin having an epoxy group and a urethane structure" according to the present invention is such that when the reaction ratio of the raw material is theoretically a hydroxyl group as described above, the crosslinking reaction is promoted. In view of the above, an acid anhydride compound which reacts with an epoxy group and a hydroxyl group is particularly preferably used as the epoxy curing agent.

The compounding amount of the acid anhydride compound can be adjusted according to the hydroxyl group derived from the above formula, and the ratio of the number of acid groups (W _OH ) and the number of epoxy groups (W _EP ) is 0.1 to 2.0. good. When the ratio of the number of acid anhydride groups to the total number of hydroxyl groups and epoxy groups is less than 0.1 or more than 2.0, the effect of the crosslinking reaction tends to be insufficient. Here, the acid anhydride group and the hydroxyl group are reacted in an equivalent ratio of 1:1, and similarly, the acid anhydride group and the epoxy group are reacted in an equivalent ratio of 1:1.

Thus, in the present invention, the "polyurethane resin having an epoxy group and a urethane structure" is in the form of a hydroxyl group, and an acid anhydride compound (particularly a tetrabasic acid anhydride) is used as an epoxy hardener. The system is preferably from the viewpoint of promoting the crosslinking reaction and improving the solvent resistance. In this case, the urethane resin preferably has a hydroxyl equivalent of from 250 to 50,000, more preferably from 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 amount exceeds 50,000, the reactivity with the acid anhydride compound is lowered, and the effect of the crosslinking reaction tends to be insufficient.

The resin composition of the present invention further contains the component (C) for the purpose of further improving the reliability of insulation. Oxazoline compounds are also available. The oxazoline compound can be exemplified by 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, laurylamine ethyl Oxazoline, dilauroyl ethyl Oxazoline, lauric oxyethyl Oxazoline, 2,2'-double (2- Oxazoline), 2,2'-extended ethyl bis (2- Oxazoline), 2,2'-butylene bis(2- D is a porphyrin), 2,2'-(1,3-phenylene) bis(2- Oxazoline), 2,2'-(1,4-phenylene) bis(2- Oxazoline) and the like. Moreover, it can also be cited that it contains such Oxazoline compound as a monomer unit Oxazoline compound, styrene ‧2-isopropenyl-2- Included in polymers such as oxazoline copolymers a compound of an oxazoline skeleton or the like. Some of these In the oxazoline compound, the crosslinking reaction can be carried out to have two or more Oxazoline skeleton Oxazoline compounds are preferred, and more in terms of reactivity, The oxazoline compound is preferred. Among them, 2,2'-(1,3-phenylene) bis(2- Oxazoline) (hereinafter, abbreviated as 1,3-PBO) is preferred. The amount of the oxazoline compound is The ratio of the oxazoline group to the acid anhydride group is preferably from 0.05 to 3.0. More preferably 0.1~2.0. If it is less than 0.05 mol equivalent, add The effect of the oxazoline compound is small, and if it exceeds 3.0, the insulation reliability is lowered.

The resin composition of the present invention may be used in combination with a curing accelerator which accelerates the curing reaction of the epoxy curing agent. Examples of the hardening accelerator include triphenylphosphine, bismuth borate compound, tetraphenylphosphonium tetraphenyl borate, n-butyl phosphonium tetraphenyl borate, and 1,8-dioxinbicyclo[5.4.0]-7- eleven. Carbene (DBU), DBU 2-ethylhexanoate, zinc octoate, tin octylate, etc., phenyl dimethyl urea, toluene bisdimethyl urea, methylene diphenyl dimethyl urea Such as urea compounds and the like.

In the resin composition of the present invention, various resin additives can be blended in the range in which the effects of the present invention are exerted. Examples of the resin additive include cerium oxide, aluminum oxide, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum borate, barium strontium titanate, and titanium. Organic filling materials such as acid strontium, calcium titanate, magnesium titanate, barium titanate, titanium oxide, barium zirconate, calcium zirconate, etc., acrylic rubber particles, polyamide fine particles, polyfluorene oxide particles, etc. a defoaming agent such as a coupling agent such as a material, a decane coupling agent, a titanate coupling agent, or an aluminum coupling agent; a polyfluorene defoaming agent; a fluorine-based antifoaming agent; and an acrylic polymer defoaming agent; Inorganic pigments such as titanium oxide and zinc oxide, organic pigments such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, and carbon black; coloring agents such as organic dyes, hindered phenol compounds, phosphorus compounds, and sulfur compounds An anti-oxidant such as a compound or an oxime-based compound, an ultraviolet absorber such as a benzotriazole-based compound or a hindered amine-based compound, a phosphorus-based compound, a flame retardant such as aluminum hydroxide or magnesium hydroxide, a leveling agent, and a touch Denaturing agent, 2,4,6-trihydrothio-s-triazole, 2,5- A dense adhesion improver such as dihydrothio-1,3,4-thiadiazole or the like.

The resin composition of the present invention is prepared by dissolving a component containing (A) an epoxy group-containing urethane resin and (B) an epoxy curing agent, using a planetary mixer, three crucibles, a bead mill or the like. Or dispersion can be modulated. In the preparation, an organic solvent for adjusting the viscosity may be used as needed. The organic solvent used for adjusting the viscosity can be the same as the organic solvent used in the above reaction. When it is used as a cover for a flexible printed circuit board, it is usually prepared into a paste-like resin composition.

When the paste-like resin composition of the present invention is applied to a designated portion of a flexible printed circuit board, and the coated surface is dried, the flexibility of the entire surface or a part of the surface protected by the resin composition of the present invention can be obtained. A printed circuit board. The drying conditions are set according to the type of the paste resin composition to be used, and can be appropriately and easily set by the manufacturer, and it is usually dried at 100 to 200 ° C for about 1 to 120 minutes. The thickness of the surface protective film to be formed is also not particularly limited, but is usually 5 to 100 μm. The flexible printed circuit board that protects the surface of the resin composition of the present invention is not particularly limited, and a flexible printed circuit board for TAB (Tape Automated Bonding), a flexible printed circuit board for COF, and multilayer flexible can be used. Various flexible printed circuit boards such as a printed circuit board and a conductive paste printed flexible printed circuit board, and the resin composition of the present invention can be suitably used as a flexible printed circuit board for TAB and flexible for COF. Coverage of printed circuit boards.

The flexible printed circuit board which protects the surface with the resin composition of the present invention can be used in various electronic machines for use. For example, it can be suitably used as a mobile phone, a digital camera, a camcorder, a game machine, a personal computer, a list machine, a hard disk drive, a plasma TV, a liquid crystal television, a liquid crystal display, a car satellite navigation system, a photocopying machine, a facsimile machine, Internal wiring of various electronic devices such as AV equipment, measurement equipment, and medical equipment.

Hereinafter, the invention will be specifically described by way of examples, but the invention is not limited thereto. In the examples, parts mean parts by mass. Further, the hydroxyl group equivalent of the hydroxyl group-containing epoxy resin of Synthesis Example 1 and the urethane resins of Synthesis Examples 2 to 6 was obtained by calculation. In Synthesis Example 1, it is considered to react with an epoxy resin (HP-7200) to form a hydroxyl group such as a phenolic hydroxyl group of bisphenol A, and Epicoat 1001 used in Synthesis Examples 3 to 5 has an epoxy group of 1 molecule. 2, and the measured value of the epoxy equivalent is considered to be twice the epoxy equivalent, and the number of hydroxyl groups in the molecule of formula 1 = (molecular weight - 57) / (228 + 58) -1

The number of hydroxyl groups in one molecule was determined. Here, "57" is a molecular weight of a glycidyl ether group, "228" is a molecular weight of bisphenol A, and "58" is a structure having a secondary hydroxyl group generated when a glycidyl ether structure reacts with a phenol group of bisphenol A. The molecular weight of the compound.

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

A 500 ml flask equipped with a stirring device, a thermometer, and a condenser was charged with a dicyclopentadiene type epoxy resin HP-7200 (manufactured by Dainippon Ink Chemicals Co., Ltd., epoxy equivalent 260), 291.4 g, bisphenol A. (Mitsui Chemical Co., Ltd.) 55.6 g, 150.0 g of diethylene glycol ethyl acetate as a solvent, and heated at 70 ° C under a nitrogen stream to obtain a homogeneous solution, after adding 2.9 g of triphenylphosphine, at 120 ° C The temperature was raised, and the reaction was carried out for 5 hours as it was, to obtain a hydroxyl group-containing epoxy resin E-1.

Properties of hydroxyl-containing epoxy resin E-1:

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

Solid formation 70%

Number average molecular weight 1,700 (GPC, converted to polystyrene)

Epoxy equivalent 538

Hydroxyl equivalent 711

<Synthesis Example 2> Synthesis of epoxy group-containing urethane resin (EU-1)

In a 500 ml flask equipped with a stirring device, a thermometer, and a condenser, 185.5 g of polycarbonate diol T-6001 (Asahi Kasei Chemicals Co., Ltd., hydroxyl group: 115 mgKOH/g) was charged, and the hydroxyl group shown in <Synthesis Example 1> was contained. Epoxy resin E-1 188.8 g, γ-butyrolactone 90.0 g, and under stirring with nitrogen, 22.3 g of 2,4-toluene diisocyanate and Ipusol #150 of dibutyltin dilaurate were added while stirring at room temperature. (1 g of a 1% solution of Idemitsu Kosan Co., Ltd.), and the product temperature (temperature of the mixture) was raised to 80 ° C for 3 hours. According to the infrared spectroscopy analysis, it was confirmed that the absorption disappeared and the reaction was terminated based on the isocyanate group, and the epoxy group-containing urethane resin EU-1 was obtained.

Properties of epoxy-containing urethane resin EU-1

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

Solid formation 70%

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

Epoxy equivalent of 1,411

Hydroxyl equivalent 1,476

<Synthesis Example 3> Synthesis of epoxy group-containing urethane resin (EU-2)

In a 500 ml flask equipped with a stirring device, a thermometer, and a condenser, 134.5 g of polycarbonate diol T-6001 (manufactured by Asahi Kasei Chemicals Co., Ltd., hydroxyl group 115 mgKOH/g) was charged as a hydroxyl group-containing epoxy resin Epicoat 1001. (Japan Epoxy Resin Co., Ltd., epoxy equivalent 475) 41.9 g, γ-butyrolactone 88.0 g, dibutyltin laurate Ipusol #150 (made by Idemitsu Kosan Co., Ltd.), 2.1 g, 1% solution, Further, 33.7 g of 4,4'-diphenylmethane diisocyanate was added in a small amount at a temperature of not more than 80 ° C while stirring at room temperature under a nitrogen stream. After the total amount of 4,4'-diphenylmethane diisocyanate was added, the temperature of the product was raised to 80 ° C for 1 hour. According to the infrared spectroscopy analysis, it was confirmed that the absorption disappeared and the reaction was terminated based on the isocyanate group, and the epoxy group-containing urethane resin EU-2 was obtained.

Properties of epoxy-containing urethane resin EU-2

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

Solid formation 70%

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

Epoxy equivalent 2,199

Hydroxyl equivalent 2,085

<Synthesis Example 4> Synthesis of epoxy group-containing urethane resin (EU-3)

A polycarbonate diol UM-CARB90 (1/3) was placed in a 500 ml flask equipped with a stirring device, a thermometer, and a condenser (manufactured by Ube Industries, Ltd., and the diol component was 1,4-cyclohexane. Methanol / 1,6-hexanediol = 1/3 of the copolycarbonate diol, hydroxyl group 126 mg KOH / g) 114.2 g, as a hydroxyl-containing epoxy resin Epicoat 1001 (made by Japan Epoxy Resin) 58.0 g of oxygen equivalent 475), 198.0 g of γ-butyrolactone, and 27.8 g of 2,4-toluene diisocyanate and 2,4-butyltin dilaurate Ipusol #150 were added while stirring at room temperature. 2.0 g of a 1% solution of a (stock) system, and the product temperature was raised to 80 ° C for 3 hours. According to the infrared spectroscopy analysis, it was confirmed that the absorption disappeared and the reaction was terminated based on the isocyanate group, and the epoxy group-containing urethane resin EU-3 was obtained.

Properties of epoxy-containing urethane resin EU-3

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

Solid formation 50%

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

Epoxy equivalent 1,443

Hydroxyl equivalent 2,928

<Synthesis Example 5> Synthesis of epoxy group-containing urethane resin (EU-4)

A polycarbonate diol UM-CARB90 (1/1) was prepared in a 500 ml flask equipped with a stirring device, a thermometer, and a condenser (manufactured by Ube Industries, Ltd.), and the diol component was 1,4-cyclohexane. Dimethanol/1,6-hexanediol = 1/1 copolycarbonate diol, hydroxyl group 124 mg KOH/g) 170.1 g, and polybutadiene diol G-1000 (made by Japan Soda Co., Ltd.) 72 mg KOH / g) 15.3 g, as a hydroxyl-containing epoxy resin Epicoat 1001 (made by Japan Epoxy Resin Co., Ltd., epoxy equivalent 475) 58.0 g, diethylene glycol ethyl acetate 117.2 g, and under a nitrogen stream, while BR>A, stirring at room temperature, while adding 24.5 g of 2,4-toluene diisocyanate, 2.8 g of a 1% solution of dibutyltin dilaurate Ipusol #150 (manufactured by Idemitsu Kosan Co., Ltd.), the temperature of the product was raised to The reaction was carried out at 80 ° C for 3 hours. According to the infrared spectroscopy analysis, it was confirmed that the absorption disappeared and the reaction was terminated based on the isocyanate group, and the epoxy group-containing urethane resin EU-4 was obtained.

Properties of epoxy group-containing urethane resin EU-4

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

Solid formation 70%

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

Epoxy equivalent 2,028

Hydroxyl equivalent 2,139

<Synthesis Example 6> Synthesis of urethane resin (U-1) not containing an 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 Kasei Chemicals Co., Ltd., hydroxyl group 115 mgKOH/g), and 121.7 g of γ-butyrolactone were placed. Under a nitrogen stream, while stirring at room temperature, a solution of 45.9 g of 2,4-toluene diisocyanate, 3.3 g of dibutyltin dilaurate Ipusol #150 (manufactured by Idemitsu Kosan Co., Ltd.) was added, and the temperature was raised. The reaction was carried out at 80 ° C for 3 hours. According to the infrared spectroscopy analysis, it was confirmed that the absorption disappeared and the reaction was terminated based on the isocyanate group, and the epoxy group-containing urethane resin U-1 was obtained.

Properties of urethane resin U-1 not containing epoxy group

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

Solid form 75%

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

Hydroxyl equivalent 2,541

[Example 1]

The epoxy group-containing urethane resin solution (EU-1) obtained in Synthesis Example 2 was converted into a solid component of 40.0 g as a tetrabasic acid dianhydride B-4400 (manufactured by Dainippon Ink Chemical Industry Co., Ltd.). , an acid anhydride equivalent of 132), 2.91 g, triphenylphosphine (manufactured by Pure Chemical Co., Ltd.), 0.21 g, as a mineral chelating agent, hydrophilic fuming cerium oxide A-380 (manufactured by Nippon Aerosil Co., Ltd.), 0.8 g, and After kneading by three roll mills, γ-butyrolactone was added to adjust the viscosity to about 20 to 40 Pa·s to prepare a thermosetting resin composition.

[Embodiment 2]

In addition to the new 1,3-PBO (Three Kingdoms Pharmaceutical Industry) Oxazolinyl equivalent 108) 3.44 g as double The thermosetting resin composition was prepared in the same manner as in Example 1 except that the oxazoline compound was 3.64 g of B-4400 and 0.24 g of triphenylphosphine.

[Example 3]

In addition to the epoxy group-containing urethane resin solution (EU-2) obtained in Synthesis Example 3, the solid form was divided into 40.0 g, 1,3-PBO was 2.22 g, and B-4400 was 2.26 g, triphenylphosphine. The thermosetting resin composition was prepared in the same manner as in Example 2 except that it was 0.22 g.

[Example 4]

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

[Example 5]

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

<Reference Example 1>

In addition to the epoxy group-free urethane resin solution (U-1) obtained in Synthesis Example 6, the solid form was divided into 45.8 g and a new epoxy resin HP-7200 (manufactured by Dainippon Ink Chemical Industry Co., Ltd.). The thermosetting resin composition was prepared in the same manner as in Example 1 except that the epoxy equivalent (260) was 4.18 g, the B-4400 was 2.13 g, the triphenylphosphine was 0.22 g, and the A-380 was 1.00 g.

<Reference Example 2>

In addition to the epoxy group-free urethane resin solution (U-1) obtained in Synthesis Example 6, the solid form was divided into 35.0 g, HP-7200 was 15.0 g, and B-4400 was 7.62 g, and triphenylphosphine was The composition of the thermosetting resin was prepared in the same manner as in Reference Example 1 except 0.29 g.

<Reference Example 3>

In addition to adding a new 1,3-PBO 1.99g as a double The thermosetting resin composition was prepared in the same manner as in Reference Example 2 except that the oxazoline compound was 9.24 g of B-4400 and 0.31 g of triphenylphosphine.

"Evaluation of Covering Materials for Electronic Circuit Surfaces to Protect Flexible Substrates"

<Evaluation of solvent resistance>

The thermosetting resin composition prepared in the examples and the reference examples was screen-printed on a 50 μm-thick polyimine film (Upirex 50S: manufactured by Ube Industries, Ltd.) using a 200-mesh plate. After 1 hour at ° C, it was hardened again at 150 ° C for 2 hours. The hardened surface was wiped with a cotton rod impregnated with acetone at a force of 400 to 500 g. If there was no abnormality, it was regarded as ○, and when the printed surface was found to be damaged, it was regarded as Δ, and the printed surface was dissolved and the exposed substrate was regarded as ×. The results are shown in Table 1.

<Evaluation of Bendingness>

The thermosetting resin composition prepared in the examples and the reference examples was screen-printed on a 50 μm-thick polyimine film (Upirex 50S: manufactured by Ube Industries, Ltd.) using a 200-mesh plate. After 1 hour at ° C, it was hardened again at 150 ° C for 2 hours. The printed surface of the polyimide film was bent 180 degrees to the outside. If the cured film does not cause whitening, it is regarded as ○, and if whitening or cracking is observed on the cured film, it is regarded as ×. The results are shown in Table 1.

<Evaluation of Bending>

The thermosetting resin composition prepared in the examples and the reference examples was applied to a 50 μm thick polyimine film (Upirex 50S: manufactured by Ube Industries, Ltd.) using a 200-mesh, 10 cm × 10 cm plate. After screen printing and hardening at 120 ° C for 1 hour, 4 pieces of 5 cm × 5 cm were cut out. These were further cured at 150 ° C for 2 hours as a test piece. The bending was caused in a form in which the printed surface was recessed via the hardened test piece. Four test pieces were placed on a smooth glass plate with the printing surface facing up, and the position at which the maximum bending apex of each test piece was floated by the glass plate was measured, and the average enthalpy of 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 the reference examples was formed on a polyimine film having a thickness of 37.5 μm by using a 200-mesh plate on a polyimine substrate having a comb-electrode pattern of 30 μm pitch. Forming a comb-electrode pattern on a polyimine substrate having an L/S=15/15 pm and a circuit thickness of 8 pm, screen-printing the pattern of the comb-shaped electrode, and at 120 ° C for 1 hour, and then Hardened at 150 ° C for 2 hours. It was applied with a voltage of 60 V and placed in an atmosphere of 120 ° C and a relative humidity of 85%. The retention time until ion migration and insulation resistance 値 reduction (up to 10 ⁶ Ω or less) was observed, and this was regarded as HAST (Highly Accelerated Temperature and Humidity Stress Test) durability time. The results are shown in Table 1.

As is understood from Table 1, the embodiment of the present invention contains (A) a polyurethane resin having an epoxy group and a urethane structure, and (B) an epoxy hardener. The resin composition for covering the printed circuit board was significantly reduced in bending of the printed circuit board as compared with Reference Examples 1 to 3. Further containing (C) In Examples 2 to 5 of the oxazoline compound, the bending was further reduced, and the electrical insulating reliability was also excellent. As described above, the thermosetting resin composition of the present invention is excellent in solvent resistance and bendability, and can be made into two phases in terms of flexibility and electrical insulation reliability.

The present application is based on Japanese Patent Application No. 2007-271600, the entire contents of which are incorporated herein by reference.

Claims (16)

A resin composition for covering a flexible printed circuit board, comprising: (A) a polyurethane resin having an epoxy group and a urethane structure, and (B) an epoxy hardener; (B) The epoxy hardener is an imidazole compound, a dicyandiamide, a decylamine derivative, a melamine derivative, a polybasic acid hydrazine compound, an aliphatic amine compound, an aromatic amine compound, a polythiol compound, an acid anhydride compound, and the like. A functional phenolic compound, or diphenylphosphonium hexafluoroantimonate. The resin composition of claim 1, wherein the polyurethane resin further has one or more structures selected from the group consisting of a polycarbonate structure, a polydiene structure, a polyester structure, and a polyether structure. The resin composition of claim 1, wherein the polyurethane resin further has a polycarbonate structure and/or a polydiene structure. The resin composition of claim 1, wherein the polyurethane resin further has a polycarbonate structure. The resin composition of claim 1, wherein the polyurethane resin is a polyol compound having (a) a molecule having two or more hydroxyl groups in the molecule, (b) having one or more hydroxyl groups in the molecule, and A polyurethane resin obtained by reacting one or more epoxy compounds of an epoxy group and (c) a polyisocyanate compound having two or more isocyanate groups in the molecule. The resin composition of claim 5, wherein the polyol compound is one or more selected from the group consisting of polycarbonate polyols, polydiene polyols, polyester polyols, and polyether polyols. The resin composition of claim 5, wherein the polyol compound is a polycarbonate polyol and/or a polydiene polyol. The resin composition of claim 5, wherein the polyol compound is a polycarbonate polyol. The resin composition of claim 1, wherein the (B) epoxy hardener is an acid anhydride compound. The resin composition of claim 1, wherein the (B) epoxy hardener is tetrabasic acid dianhydride. For example, the resin composition of claim 1 is further contained (C) Oxazoline compound. Such as the resin composition of claim 11 of the patent scope, wherein (C) Oxazoline compound is double Oxazoline compound. The resin composition of claim 1, wherein the resin composition is a paste resin composition. The resin composition of claim 1, which further comprises a hardening accelerator. A flexible printed circuit board characterized by a cured surface of a resin composition according to any one of claims 1 to 14. An electronic machine characterized by incorporating a flexible printed circuit board as claimed in claim 15.