JP2013199656A - Thermosetting resin composition and cured product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosetting resin composition suitable for forming a flexible coated film showing excellence in adhesion to a base material, folding resistance, low warpage, solder heat resistance, electroless gold plating resistance, electric insulation and the like, and to provide a printed wiring board on which a protective film and an insulation layer each composed of the cured product are formed.SOLUTION: A thermosetting resin composition includes (A) an oligomer containing a group reacting with an epoxy group derived from an alicyclic or aliphatic isocyanate and (B) an epoxy resin as a thermosetting resin. The thermosetting resin composition preferably contains (C) a curing accelerator and an inorganic and/or organic filler.

Description

  The present invention is a thermosetting resin composition suitable for forming a flexible film excellent in adhesion to a substrate, folding resistance, low warpage, solder heat resistance, electroless gold plating resistance, electrical insulation, etc. Protective films and insulating materials made of cured products thereof, and protective films and insulating layers such as solder resists and interlayer insulating films used in the manufacture of printed wiring boards, particularly flexible printed wiring boards and tape carrier packages Protective film for back electrodes of electroluminescent panels used for backlights of liquid crystal displays and displays for information display, protective films for display panels of cell phones, watches, car stereos, ICs and VLSIs Useful for sealing materials.

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

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

  Further, as a conventional thermosetting solder resist ink, an epoxy resin resist having an epoxy resin and a long-chain dibasic acid anhydride as essential components as disclosed in JP-B-5-75032 (Patent Document 1). Although there is an ink composition, when it is adjusted to give flexibility to the film to be formed, the adhesion with the polyimide of the base material is deteriorated, and the plating resistance, PCT resistance and solder heat resistance are reduced. There's a problem.

Therefore, in Japanese Patent Application Laid-Open No. 2006-117922 (Patent Document 2), (A) one molecule has two or more carboxyl groups and is formed by the reaction of polycarbonate diol (a) and polyisocyanate (b). A thermosetting resin composition containing a polyurethane having a urethane bond and (B) a thermosetting component has been proposed. By using such a carboxyl group-containing urethane resin in combination with an epoxy resin as a thermosetting component, the problems of the conventional solder resist ink described above can be solved, but the characteristics such as solder heat resistance should still be improved. The point was left.
Japanese Patent Publication No. 5-75032 (Claims) JP 2006-117922 A (Claims)

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

  In order to achieve the above object, according to the present invention, (A) an oligomer containing a group that reacts with an epoxy group derived from an alicyclic or aliphatic isocyanate, and (B) an epoxy as a thermosetting compound A thermosetting resin composition comprising a resin is provided.

In a preferred embodiment, it is preferable to further contain (C) a curing accelerator. Furthermore, an inorganic and / or organic filler can be contained, and an organic solvent can be contained as necessary.
Furthermore, according to the present invention, there are also provided a cured product obtained by curing the thermosetting resin composition, and a printed wiring board in which a part or all of the surface is coated with the cured product.

  The thermosetting resin composition of the present invention is capable of forming a flexible film excellent in adhesion to a substrate, folding resistance, low warpage, solder heat resistance, electroless gold plating resistance, electrical insulation and the like. Is suitable.

  Further, the thermosetting resin composition of the present invention containing an oligomer containing a group that reacts with an epoxy group derived from an alicyclic or aliphatic isocyanate together with a thermosetting compound is excellent in flexibility. In addition, it is useful as a protective film such as a solder resist or an insulating resin material used in the manufacture of flexible printed wiring boards and tape carrier packages. Moreover, since the film obtained from such a thermosetting resin composition does not warp after thermosetting, it is easy to mount components or chips on a flexible printed wiring board or a tape carrier package. Therefore, by using the thermosetting resin composition of the present invention, flexibility excellent in various properties such as adhesion, folding resistance, low warpage, electroless gold plating resistance, solder heat resistance, and electrical insulation. The protective film can be formed at low cost with high productivity.

As a result of earnest research to achieve the above-mentioned problems, the present inventors have found that (a) a polyisocyanate compound, (b) a compound having two or more alcoholic hydroxyl groups, and (c) a primary amino group. The amino group-containing urethane oligomer obtained by reacting with the compound to be contained has excellent adhesion to the substrate mentioned as a property derived from the amino group, and further, this amino group is heated during thermosetting. It has been found that a crosslinking reaction with a functional group of a curable compound, for example, an epoxy group of an epoxy resin, can improve characteristics such as solder heat resistance. Generally, the lower the crosslink density of the resin, the greater the flexibility of the formed film and the less the warp of the film after thermosetting. However, when the crosslink density is lowered, characteristics such as solder heat resistance, plating resistance, chemical resistance, and the like of the obtained film are likely to be lowered. In the present invention, by using an oligomer containing a group that reacts with an epoxy group derived from an alicyclic or aliphatic isocyanate, high reactivity derived from a group that reacts with an epoxy group and adhesion to a substrate can be achieved. Can be improved. In addition, because it has excellent flexibility derived from the urethane structure, it uses high-Tg epoxy resin or polyfunctional epoxy with high performance that is generally difficult to use for solder resists for flexible substrates. It has become possible to improve the properties such as solder heat resistance while maintaining low warpage.
Hereinafter, each component of the thermosetting resin composition of this invention is demonstrated in detail.

  First, the oligomer (A) of the present invention comprises (a) a polyisocyanate compound, (b) a compound having two or more alcoholic hydroxyl groups, and (c) a primary amino group (a group that reacts with an epoxy group). It is preferable that it is a urethane oligomer which has the amino group (group which reacts with an epoxy group) introduce | transduced into the terminal by reaction with the compound containing this.

  For example, in the case of the suitable urethane oligomer, the oligomer (A) is obtained by reacting (a) a polyisocyanate compound and (b) a compound having two or more alcoholic hydroxyl groups as a first reaction, As the second reaction, it is preferable to react (c) a compound containing a primary amino group.

  The reaction proceeds without catalyst by stirring and mixing at room temperature to 100 ° C, but it is preferable to heat to 70 to 100 ° C in order to increase the reaction rate.

  As said polyisocyanate compound (a), conventionally well-known various polyisocyanate can be used, and it is not limited to a specific compound. Specific examples of the (branched) aliphatic or alicyclic isocyanate (a) used in the synthesis of the preferred urethane oligomer include, for example, aliphatic diisocyanates such as hexamethylene diisocyanate, and branched fats such as trimethylhexamethylene diisocyanate. Cycloaliphatic diisocyanate, isophorone diisocyanate, (o, m, or p) -hydrogenated xylylene diisocyanate, methylene bis (cyclohexyl isocyanate), cyclohexane-1,3-dimethylene diisocyanate, cyclohexane-1,4-dimethylene diisocyanate, etc. And formula diisocyanates. Among these, hexamethylene diisocyanate which is an aliphatic diisocyanate and trimethylhexamethylene diisocyanate which is a branched aliphatic diisocyanate are preferable. In addition, diisocyanates having an aromatic ring such as (o, m, or p) -xylylene diisocyanate can also be used. These diisocyanates can be used alone or in admixture of two or more. When these diisocyanates are used, a cured product excellent in low warpage can be obtained.

  Next, as the compound (b) having two or more alcoholic hydroxyl groups, conventionally known various polyols can be used and are not limited to specific compounds, but polycarbonate polyols such as polycarbonate diol, polyether polyols, Polyester polyol, polyolefin polyol, polybutadiene polyol, polyisoprene polyol, hydrogenated polybutadiene polyol, hydrogenated isoprene polyol, acrylic polyol, bisphenol A alkylene oxide adduct diol, phosphorus-containing polyol, carboxyl group and two A compound having the above alcoholic hydroxyl group, a phenolic hydroxyl group and a compound having two or more alcoholic hydroxyl groups can be suitably used.The polycarbonate diol is derived from a polycarbonate diol (b-1) containing a repeating unit derived from one or more linear aliphatic diols as a constituent unit, derived from one or two or more alicyclic diols. Polycarbonate diol (b-2) containing a repeating unit as a constituent unit, or polycarbonate diol (b-3) containing a repeating unit derived from both a linear aliphatic diol and an alicyclic diol as a constituent unit. It is done. The compound (b) having two or more alcoholic hydroxyl groups can be used alone or in admixture of two or more.

  Specific examples of the polycarbonate diol (b-1) containing as a constituent unit a repeating unit derived from one or more linear aliphatic diols are derived from 1,6-hexanediol, for example. Polycarbonate diol, polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol, polycarbonate diol derived from 1,4-butanediol and 1,6-hexanediol, 3-methyl-1,5 -Polycarbonate diol derived from pentanediol and 1,6-hexanediol, polycarbonate diol derived from 1,9-nonanediol and 2-methyl-1,8-octanediol, and the like.

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

  Specific examples of the polycarbonate diol (b-3) containing as a constituent unit a repeating unit derived from both a linear aliphatic diol and an alicyclic diol include 1,6-hexanediol and 1 Polycarbonate diol derived from 1,4-cyclohexanedimethanol.

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

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

  Examples of the bisphenol A-based alkylene oxide adduct include bisphenol A ethylene oxide adduct, propylene oxide adduct, butylene oxide adduct, etc. Among them, bisphenol A propylene oxide adduct is preferable.

  Specific examples of the phosphorus-containing polyol include FC-450 (Asahi Denka Kogyo Co., Ltd.), M-Ester (Sanko Co., Ltd.), M-Ester-HP (Sanko Co., Ltd.) and the like. . By using these phosphorus-containing polyols, a phosphorus compound can be introduced into the urethane resin, and flame retardancy can be imparted.

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

  Specific examples of the compound (c) containing a primary amino group used in the present invention include aliphatic polyamines such as diaminobutane, hexamethylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, and isophoronediamine. 1,3-bisaminomethylcyclohexane, bis (4-aminocyclohexyl) methane, norbornenediamine, 1,2-diaminocyclohexane, and other alicyclic polyamines.

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

  In the thermosetting resin composition of the present invention, the thermosetting compound (B) blended together with the oligomer (A) is an epoxy resin or oxetane compound having two or more epoxy groups, oxetanyl groups, etc. in one molecule. Can be preferably used, but an epoxy resin is particularly preferable.

  Specific examples of the epoxy resin include, for example, bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, novolac type epoxy resin, phenol Novolac type epoxy resin, cresol novolac type epoxy resin, N-glycidyl type epoxy resin, bisphenol A novolac type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin, chelate type epoxy resin, glyoxal type epoxy resin, containing amino group Epoxy resin, rubber-modified epoxy resin, dicyclopentadiene phenolic epoxy resin, diglycidyl phthalate resin, heterocyclic epoxy resin, tetraglycidyl chloride Renoiruetan resins, silicone-modified epoxy resins, such as ε- caprolactone-modified epoxy resin.

More preferable epoxy resins that can easily obtain a cured product having a high Tg include N-glycidyl type epoxy resins, bixylenol type epoxy resins, biphenol type epoxy resins, tetraglycidyl xylenoyl ethane resins, tetrakisphenol ethane type epoxy resins, Examples thereof include cyclopentadiene phenolic epoxy resins and naphthalene skeleton-containing epoxy resins. Specifically, tetrakisphenolethane epoxy resin GTR-1800 (manufactured by Nippon Kayaku Co., Ltd.), dicyclopentadiene phenolic epoxy resin HP-7200 (manufactured by Dainippon Ink & Chemicals, Inc.), HP-4032D, EXA-7240, EXA-4700, EXA-4770 (all of which are Dainippon Ink Chemical Co., Ltd.) Manufactured), EXA-7335 (produced by Dainippon Ink & Chemicals, Inc.) which is an epoxy resin having a xanthene skeleton, and NC-3000 (produced by Nippon Kayaku Co., Ltd.) which is a biphenol novolac epoxy resin. By using a polyfunctional epoxy resin, other trifunctional and tetrafunctional epoxy resins, etc., characteristics such as solder heat resistance can be improved.
Further, in order to impart flame retardancy, a material in which an atom such as halogen such as chlorine or bromine or phosphorus is introduced into the structure may be used.

  In the thermosetting resin composition of the present invention, the thermosetting compound (B) is used alone or as a mixture of two or more. The blending amount is 5 to 1000 parts by mass, preferably 10 to 500 parts by mass with respect to 100 parts by mass of the oligomer as component (A). If it is less than 5 parts by mass, the solder heat resistance of the cured film of the thermosetting resin composition may be insufficient. On the other hand, if it exceeds 1000 parts by mass, it is used as an insulating protective film for a flexible printed wiring board (FPC). In this case, various characteristics, particularly electrical insulation, tend to deteriorate.

  The curing accelerator (C) used in the present invention accelerates the thermosetting reaction and is used to further improve the properties such as adhesion, chemical resistance, and heat resistance. Specific examples of such curing accelerators include imidazole and its derivatives (for example, 2MZ, 2E4MZ, C11Z, C17Z, 2PZ, 1B2MZ, 2MZ-CN, 2E4MZ-CN, C11Z-CN, manufactured by Shikoku Kasei Kogyo Co., Ltd.). 2PZ-CN, 2PHZ-CN, 2MZ-CNS, 2E4MZ-CNS, 2PZ-CNS, 2MZ-AZINE, 2E4MZ-AZINE, C11Z-AZINE, 2MA-OK, 2P4MHZ, 2PHZ, 2P4BHZ, etc.); Guanamines; polyamines such as diaminodiphenylmethane, m-phenylenediamine, m-xylenediamine, diaminodiphenylsulfone, dicyandiamide, urea, urea derivatives, melamine, polybasic hydrazides; their organic acid salts and / or Epoxy adduct; amine complex of boron trifluoride; triazine derivatives such as ethyldiamino-S-triazine, 2,4-diamino-S-triazine, 2,4-diamino-6-xylyl-S-triazine; Ethanolamine, N, N-dimethyloctylamine, N-benzyldimethylamine, pyridine, N-methylmorpholine, hexa (N-methyl) melamine, 2,4,6-tris (dimethylaminophenol), tetramethylguanidine, m -Amines such as aminophenol; polyphenols such as polyvinylphenol, polyvinylphenol bromide, phenol novolak, alkylphenol novolak; organic phosphine such as tributylphosphine, triphenylphosphine, tris-2-cyanoethylphosphine Fins; Phosphonium salts such as tri-n-butyl (2,5-dihydroxyphenyl) phosphonium bromide and hexadecyltributylphosphonium chloride; Quaternary ammonium salts such as benzyltrimethylammonium chloride and phenyltributylammonium chloride; Diphenyliodonium tetrafluoroboroate, triphenylsulfonium hexafluoroantimonate, 2,4,6-triphenylthiopyrylium hexafluorophosphate, Irgacure (registered trademark) 261 manufactured by Ciba Specialty Chemicals Co., Ltd. ) Photocationic polymerization catalyst such as ADEKA OPTOMA-SP-170; styrene-maleic anhydride resin; equimolar reaction product of phenyl isocyanate and dimethylamine, Examples thereof include known and commonly used curing accelerators or curing agents such as an equimolar reaction product of organic polyisocyanate such as tolylene diisocyanate and isophorone diisocyanate and dimethylamine.

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

  The thermosetting resin composition of the present invention is prepared by mixing the oligomer (A), the thermosetting compound (B), and optionally a curing accelerator (C), a filler, etc. with a mixer such as a disper, a kneader, 3 It can be obtained by dissolving or dispersing using the present roll mill, bead mill or the like. In that case, you may use the solvent inactive with respect to an epoxy group or a phenolic hydroxyl group. Such an inert solvent is preferably an organic solvent.

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

The thermosetting resin composition of the present invention contains a compound having a carboxyl group and / or a phenolic hydroxyl group for the purpose of improving the properties such as adhesion, hardness, heat resistance and the like within a range not impairing the effects of the present invention. Can be contained. As the compound having a carboxyl group and / or a phenolic hydroxyl group, any compound can be used as long as it has a carboxyl group and / or a phenolic hydroxyl group, and is not limited to a specific one. Among these, for example, the following resins are preferable.
(1) a carboxyl group-containing resin obtained by co-polymerizing an unsaturated carboxylic acid and a compound having an unsaturated double bond,
(2) a carboxyl group-containing resin obtained by reacting a polyfunctional epoxy compound with a saturated or unsaturated monocarboxylic acid and reacting the resulting secondary hydroxyl group with a polybasic acid anhydride,
(3) a carboxyl group-containing resin obtained by reacting a hydroxyl group-containing polymer with a polybasic acid anhydride,
(4) Polyisocyanate compound, polyol compound, compound having two or more alcoholic hydroxyl groups and one carboxyl group, carboxyl group-containing resin obtained by addition reaction of four kinds of compounds with one hydroxyl group compound ,
(5) polyfunctional phenolic resin,
(6) Polyisocyanate compound, polyol compound, phenolic hydroxyl group-containing resin obtained by addition reaction of three kinds of compounds of alcoholic hydroxyl group and compound having phenolic hydroxyl group, and (7) polyisocyanate compound, polyol Compound, a compound having two or more alcoholic hydroxyl groups and one carboxyl group, a carboxyl group and a phenolic hydroxyl group obtained by the addition reaction of four kinds of compounds of an alcoholic hydroxyl group and a compound having a phenolic hydroxyl group Containing resin.
Among these, in order to improve properties such as adhesion, hardness, heat resistance, etc. without impairing flexibility and low warpage of the obtained cured product, the above (4), (6) and ( It is particularly desirable to add the carboxyl group-containing resin of 7).

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

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

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

  The thermosetting resin composition having the above composition can be applied to a printed circuit board by various known methods such as curtain coating, roll coating, spray coating, and dip coating, as well as dry film. Alternatively, it can be used for various forms and applications such as prepreg. Various solvents can be used depending on the method of use and application, but in some cases, not only good solvents but also poor solvents can be used.

  The thermosetting resin composition of the present invention is applied to a flexible printed wiring board, a tape carrier package or an electroluminescent panel on which a circuit is formed by a screen printing method, and heated to a temperature of 120 to 180 ° C., for example. Solder resist film with excellent adhesion to substrate, folding resistance, low warpage, electroless gold plating resistance, solder heat resistance, electrical insulation, etc. And a protective film is formed.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following, “parts” and “%” are based on mass unless otherwise specified.

Synthesis Example 1 <Synthesis example of amino group-containing urethane oligomer>
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, 280 g of hexamethylene diisocyanate as polyisocyanate was added to 300 g of dimethylformamide and stirred at room temperature. After the inside of the flask is uniformly mixed, the solution is raised to 70 ° C. and a polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol as a compound having two or more alcoholic hydroxyl groups ( 800 g of the number average molecular weight 800) was added while stirring, and stirring was continued at 70 ° C. for 15 hours to obtain a urethane oligomer.
Subsequently, 330 g of dimethylformamide and 130 g of norbornenediamine were charged into a reaction vessel equipped with a stirrer, a thermometer, and a condenser, stirred at room temperature, and after confirming that the flask was uniformly mixed, 540 g of the obtained urethane oligomer was dividedly added over 2 hours, and the reaction temperature was raised from room temperature to 70 ° C. Furthermore, the reaction temperature was kept at 70 ° C. and stirring was performed for 5 hours. The reaction was terminated after confirming that the absorption spectrum (2280 cm ⁻¹ ) of the isocyanate group had disappeared in the infrared absorption spectrum, and an amino group-containing urethane oligomer (hereinafter abbreviated as “varnish A”) having a solid content of 67 wt% was obtained. .

Synthesis Example 2 <Synthesis example of carboxyl group-containing urethane oligomer>
Polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol (number average molecular weight 800) as a compound having two or more alcoholic hydroxyl groups in a reaction vessel equipped with a stirrer, a thermometer and a condenser. ) 360 g, dimethylolbutanoic acid 81.4 g and n-butanol 11.8 g as a reaction terminator were added. Next, 151.2 g of hexamethylene diisocyanate was added, and the mixture was heated to 60 ° C. with stirring and stopped. When the temperature in the reaction vessel began to decrease, the mixture was heated again and stirred at 80 ° C. The reaction was terminated after confirming that the absorption spectrum of the isocyanate group (2280 cm ⁻¹ ) had disappeared by spectrum. Next, carbitol acetate was added so that the solid content was 50 wt%, and a viscous liquid carboxyl group-containing urethane oligomer (hereinafter abbreviated as varnish B) containing a diluent was obtained. The acid value of the solid content of the obtained urethane oligomer was 51.0 mgKOH / g.

Synthesis Example 3 <Synthesis example of urethane oligomer>
Polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol (number average molecular weight 800) as a compound having two or more alcoholic hydroxyl groups in a reaction vessel equipped with a stirrer, a thermometer and a condenser. ) 800 g, n-butanol 11.8 g was added. Next, 151.2 g of hexamethylene diisocyanate was added, and the mixture was heated to 60 ° C. with stirring and stopped. When the temperature in the reaction vessel began to decrease, the mixture was heated again and stirred at 80 ° C. to absorb infrared rays. The reaction was terminated after confirming that the absorption spectrum of the isocyanate group (2280 cm ⁻¹ ) had disappeared by spectrum. Next, carbitol acetate was added so that the solid content was 50 wt%, and a viscous liquid urethane oligomer (hereinafter abbreviated as “varnish C”) containing a diluent was obtained.

Examples 1 to 8 and Comparative Examples 1 and 2
A thermosetting resin composition was prepared by mixing each component and blending ratio shown in Table 1 with a three-roll mill at room temperature. The obtained thermosetting resin composition was applied to a substrate by screen printing, and thermosetting was performed at 150 ° C. for 60 minutes.

About the cured film of each said thermosetting resin composition, the following various characteristics were evaluated with the following method. The results are shown in Table 2.
(1) Adhesiveness Each of the thermosetting resin compositions of Examples 1 to 8 and Comparative Examples 1 and 2 was printed on the entire surface by screen printing on Kapton 100H (a polyimide film manufactured by Toray DuPont Co., Ltd., thickness 25 μm) And cured at 150 ° C. for 60 minutes. The adhesion of the cured film was confirmed by the presence or absence of peeling of the resist layer by a peeling test using a cellophane adhesive tape, and evaluated according to the following criteria.
○: No peeling at all.
Δ: Slightly peeled off.
X: There is peeling.

(2) Folding resistance Each surface of the thermosetting resin compositions of Examples 1 to 8 and Comparative Examples 1 and 2 was screen-printed on Kapton 100H (a polyimide film manufactured by Toray DuPont Co., Ltd., thickness 25 μm). Printed and heat cured at 150 ° C. for 60 minutes. The obtained cured film was bent 180 ° and evaluated according to the following criteria.
○: The cured film has no cracks.
Δ: The cured film has some cracks.
X: The cured film has cracks.

(3) Low warpage The entire surface of each of the thermosetting resin compositions of Examples 1 to 8 and Comparative Examples 1 and 2 was screen-printed on Kapton 100H (a polyimide film manufactured by Toray DuPont Co., Ltd., thickness 25 μm). Printed and heat cured at 150 ° C. for 60 minutes. After cooling, the obtained cured film was cut out to 50 × 50 mm, and the average was obtained by measuring four-way warpage, and evaluated according to the following criteria.
○: The warp is less than 1 mm.
(Triangle | delta): The curvature is 1 or more and less than 5 mm.
X: The warp is 5 mm or more.

(4) Electroless gold plating resistance Each of the thermosetting resin compositions of Examples 1 to 8 and Comparative Examples 1 and 2 was pattern-printed on a printed circuit board (thickness: 1.6 mm), and 60 ° C. at 60 ° C. A test piece was obtained by heat curing for minutes. Using the obtained test piece, electroless gold plating was performed in the steps described later, and the electroless gold plating resistance was evaluated according to the following criteria.
○: The cured film has no swelling, peeling, or discoloration.
Δ: Slightly blistered, peeled off, or discolored on the cured film.
X: The cured film has blistering, peeling and discoloration.

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

(5) Solder heat resistance Each of the thermosetting resin compositions of Examples 1 to 8 and Comparative Examples 1 and 2 was subjected to pattern printing on a printed circuit board (thickness 1.6 mm) and heated at 150 ° C. for 60 minutes. Cured. A rosin-based flux was applied to the obtained cured film and immersed in a solder bath at 260 ° C. for 10 seconds, and the state of the cured film was evaluated according to the following criteria.
A: The cured film does not blister, peel off or discolor even after 10 seconds of immersion twice.
○: The cured film has no swelling, peeling, or discoloration.
Δ: Slightly blistered, peeled off, or discolored on the cured film.
X: The cured film has blistering, peeling and discoloration.

(6) Electrical insulation The thermosetting resin compositions of Examples 1 to 8 and Comparative Examples 1 and 2 were each L / S = 20/20 μm polyimide substrate (Espanex, manufactured by Nippon Steel Chemical Co., Ltd.) (Registered trademark)) A coating film was formed on it and thermally cured at 150 ° C for 60 minutes. The electrical insulation of the obtained cured film was evaluated under the following conditions and criteria.
Humidification conditions: temperature 120 ° C., humidity 85% RH, applied voltage 60 V, 100 hours Measurement conditions: measurement time 60 seconds, applied voltage 60 V
○: Insulation resistance value after humidification of 10 ⁹ Ω or more, no copper migration.
Δ: Insulation resistance value after humidification of 10 ⁹ Ω or more, copper migration.
X: Insulation resistance value after humidification of 10 ⁸ Ω or less, copper migration.

About the cured film of each said thermosetting resin composition, the following methods evaluated the following various characteristics on the board | substrate which carried out the pre-tin plating process. The results are shown in Table 3.
(7) Adhesion on tin plating The thermosetting resin compositions of Examples 1 to 8 and Comparative Examples 1 and 2 are each subjected to a tin plating treatment of L / S (line / space) = 15/15 μm. A coating film was formed on a polyimide substrate (a substrate plated with S'PERFLEX manufactured by Sumitomo Metal Mining Co., Ltd.), thermally cured at 120 ° C. for 60 minutes, and then 7.5 ° C. at 125 ° C. Time curing was performed. The adhesion of the cured film on tin plating was confirmed by the presence or absence of peeling of the resist layer by a peeling test using a cellophane adhesive tape, and evaluated according to the following criteria.
○: No peeling at all.
Δ: Slightly peeled off.
X: There is peeling.

(8) Electrical insulation Polyimide substrate (Sumitomo) in which each thermosetting resin composition of Examples 1 to 5 and Comparative Example 1 is subjected to tin plating of L / S (line / space) = 15/15 μm. Create a coating film on the metal mining Co., Ltd. Esperflex (S'PERFLEX) tin-plated substrate, heat cure at 120 ° C for 60 minutes, then heat cure at 125 ° C for 7.5 hours went. The electrical insulation of the obtained cured film was evaluated under the following conditions and criteria.
Humidification conditions: temperature 120 ° C., humidity 85% RH, applied voltage 60 V, 100 hours Test conditions: measurement time 60 seconds, applied voltage 60 V, measured at room temperature ○: insulation resistance value after humidification 10 ⁹ Ω or more, occurrence of migration None.
Δ: Insulation resistance value after humidification is 10 ⁹ Ω or more and migration occurs.
X: Insulation resistance value after humidification is 10 ⁸ Ω or less, and migration occurs.

  As is clear from the results shown in Tables 2 and 3 above, the cured film formed from the thermosetting resin composition of the present invention has adhesion to the substrate, folding resistance, low warpage, and electroless gold plating resistance. Excellent solder heat resistance and electrical insulation. Furthermore, good results could be obtained even on the substrate subjected to the pre-tin plating treatment. On the other hand, in the case of Comparative Examples 1 and 2 using urethane oligomers that do not contain amino groups (varnish B, C), there was no problem in adhesion to the substrate, folding resistance, and low warpage, It was inferior in electroless gold plating resistance, solder heat resistance and electrical insulation.

Claims (5)

  A thermosetting resin comprising (A) an oligomer containing a group that reacts with an epoxy group derived from an alicyclic or aliphatic isocyanate, and (B) an epoxy resin as a thermosetting compound. Composition.   The thermosetting resin composition according to claim 1, further comprising (C) a curing accelerator.   Furthermore, an inorganic and / or organic filler is contained, The thermosetting resin composition of Claim 1 or 2 characterized by the above-mentioned.   Hardened | cured material formed by hardening | curing the thermosetting resin composition of any one of the said Claims 1-3.   The printed wiring board by which one part or all part of the surface was coat | covered with the hardened | cured material of the thermosetting resin composition of any one of the said Claims 1-3.