WO2009145224A1 - Epoxy resin composition for printed wiring board, solder resist composition, resin film, resin sheet, prepreg, metal foil with resin, cover lay, and flexible printed wiring board - Google Patents

Abstract

Disclosed is an epoxy resin composition for printed wiring boards, which can improve all of storage stability, adhesion, bendability and fillability. The epoxy resin composition for printed wiring boards contains, as essential components, (A) an epoxy resin, (B) an epoxy resin curing agent and (C) a carbodiimide-modified soluble polyamide.

Description

Epoxy resin composition for printed wiring board, solder resist composition, resin film, resin sheet, prepreg, metal foil with resin, coverlay, flexible printed wiring board

The present invention relates to an epoxy resin composition for a printed wiring board, a solder resist composition, a resin film, a resin sheet, a prepreg, a resin-coated metal foil (resin sheet with a metal foil) used in the production of a printed wiring board such as a flexible printed wiring board. ) And coverlays and flexible printed wiring boards formed using these.

Many flexible printed wiring boards are used in small and thin electronic devices. Recently, the demand for multilayered flexible printed wiring boards has increased due to the demand for higher density and lower thickness.・ Cost is severe. Conventionally, bonding sheets and coverlays are known as multilayered materials for flexible printed wiring boards. These bonding sheets and coverlays used as insulating build-up materials have not only storage stability, press-formability such as through-holes and circuit fillability, but also flexibility, heat resistance, and chemical resistance as flexible printed wiring boards. Electrical insulation is required. Accordingly, a resin composition obtained by blending NBR or acrylic rubber having excellent flexibility with an epoxy resin having excellent insulation, heat resistance, and chemical resistance is used for bonding sheets and coverlays.

However, the varnish and sheet storage stability of such a resin composition is insufficient, and the electric insulation, heat resistance, and chemical resistance of the flexible printed wiring board obtained using the resin composition are not satisfactory. . For this reason, it is also possible to use a resin composition obtained by blending an epoxy resin with polyamideimide or polyamide, which is superior in chemical resistance, heat resistance, insulation, flame retardancy and flexibility than synthetic rubber such as NBR and acrylic rubber. However, the press formability such as varnish storage stability, sheet storage stability, through-hole and circuit filling properties is still not sufficient. Moreover, when the storage stability and press formability are improved, other characteristics that have been favorable are deteriorated.

Moreover, the electrical insulation, heat resistance, and chemical resistance of the flexible printed wiring board obtained by using the resin composition as described above were not satisfactory.

There is also a strong demand from the market for the flame retardancy of electronic components due to the demand for safety of electronic equipment. As flame retarding technology for electronic components, halogen compounds represented by brominated epoxy have been widely used. On the other hand, there is a concern to ban or regulate the use of harmful substances in electrical products, etc. because of concerns about the global environment protection and adverse effects on the human body, but halogenated compounds may generate toxic gases during incineration. For this reason, the development of halogen-free flame retardant technology that does not use halogen compounds has become a trend.

Examples of halogen-free flame retardants that can replace halogen-based compounds are organic phosphorus compounds represented by phosphate esters (see, for example, Patent Document 2). However, in this case, in order to impart sufficient flame retardancy to the composition, it is necessary to use a large amount of an organic phosphorus compound, so that the glass transition temperature (Tg) of the cured product is lowered, and the heat resistance, There is a problem that the chemical resistance and the like are remarkably lowered.
JP 11-14164 A JP 2008-56820 A

The present invention has been made in view of the above points. First, an epoxy resin composition for a printed wiring board and a solder resist composition that can improve storage stability, adhesion, flexibility, and filling properties. Products, resin films, resin sheets, prepregs, metal foils with resin, coverlays, flexible printed wiring boards, and secondly, they are highly insulating and flexible and contain halogen Epoxy resin composition for printed wiring boards, solder resist composition, resin film, resin sheet, which has high flame retardancy without deterioration of glass transition temperature (Tg) and has high heat resistance and chemical resistance, An object of the present invention is to provide a prepreg, a metal foil with resin, a coverlay, and a flexible printed wiring board.

The epoxy resin composition for a printed wiring board according to claim 1 of the present invention contains (A) an epoxy resin, (B) an epoxy resin curing agent, and (C) a carbodiimide-modified soluble polyamide as essential components. It is what.

The invention according to claim 2 is characterized in that, in claim 1, the content of component (C) is 20 to 70% by mass with respect to the total amount of components (A), (B) and (C). It is.

The invention according to claim 3 is characterized in that, in claim 1 or 2, an epoxy resin having a naphthalene skeleton is used as the component (A).

The invention according to claim 4 is characterized in that, in claim 3, as the epoxy resin having a naphthalene skeleton, at least one of those represented by the following structural formulas (1) to (3) is used. To do.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, at least one of aminotriazine novolak resin and dicyandiamide represented by the following structural formula (4) is used as the component (B). It is characterized by being.

The invention according to claim 6 is the reaction product according to any one of claims 1 to 5, wherein 0.5 to 20 parts by mass of a carbodiimide compound is added as a component (C) to 100 parts by mass of the soluble polyamide. What was obtained is used, It is characterized by the above-mentioned.

The invention according to claim 7 is characterized in that, in any one of claims 1 to 6, a phenoxy resin is contained.

The invention according to claim 8 is characterized in that in any one of claims 1 to 7, at least one of a phosphorus-modified epoxy resin, a phosphorus-modified phenoxy resin, and a phosphorus-based flame retardant is contained. Is.

The invention according to claim 9 is the invention according to claim 8, characterized in that an aluminum alkylphosphinate represented by the following structural formula (5) is used as the phosphorus-based flame retardant.

The invention according to claim 10 is the invention according to claim 9, wherein the content of aluminum alkylphosphinate represented by the structural formula (5) is 5 to 20 with respect to the total amount of components (A), (B) and (C). It is characterized by being mass%.

A solder resist composition according to an eleventh aspect of the present invention comprises the epoxy resin composition for a printed wiring board according to any one of the first to tenth aspects.

The resin film according to claim 12 of the present invention is characterized in that the epoxy resin composition for printed wiring board according to any one of claims 1 to 10 is formed into a film shape.

A resin sheet according to claim 13 of the present invention is characterized in that the epoxy resin composition for a printed wiring board according to any one of claims 1 to 10 is formed into a sheet shape.

A prepreg according to claim 14 of the present invention is characterized in that the substrate is impregnated with the epoxy resin composition for printed wiring board according to any one of claims 1 to 10 and is in a semi-cured state. To do.

The metal foil with resin according to claim 15 of the present invention is in a semi-cured state by applying the epoxy resin composition for printed wiring board according to any one of claims 1 to 10 to the metal foil. It is characterized by.

The metal foil with resin according to claim 16 of the present invention is the epoxy resin composition 1 for printed wiring board according to any one of claims 1 to 10, wherein the coated resin 2 and the film-like material 3 It is characterized in that it is applied to the metal foil 5 through at least one insulating layer 4 and is in a semi-cured state.

A coverlay according to claim 17 of the present invention is characterized in that the epoxy resin composition for printed wiring boards according to any one of claims 1 to 10 is applied to a plastic sheet and is in a semi-cured state. It is what.

A coverlay according to claim 18 of the present invention is characterized by comprising the resin-attached metal foil according to claim 15 or 16.

A flexible printed wiring board according to claim 19 of the present invention is a solder resist composition according to claim 11, a resin film according to claim 12, a resin sheet according to claim 13, and a prepreg according to claim 14. A metal foil with resin according to claim 15, a metal foil with resin according to claim 16, a cover lay according to claim 17, and a cover lay according to claim 18. It is characterized by being.

According to the epoxy resin composition for a printed wiring board according to claim 1 of the present invention, the storage stability, adhesion, flexibility, and filling properties can be improved by the carbodiimide-modified soluble polyamide.

According to the invention of claim 2, the flexibility and chemical resistance can be improved.

According to the invention of claim 3, heat resistance, migration resistance, and chemical resistance can be improved.

According to the invention of claim 4, the heat resistance, migration resistance, and chemical resistance can be further improved.

According to the invention of claim 5, flame retardancy and chemical resistance can be enhanced, and long-term product storage stability (B-stage storage stability) can be improved.

According to the invention of claim 6, it is possible to sufficiently improve the moisture resistance and heat resistance and to prevent the plasticity from becoming too high or the impact resistance from being impaired.

According to the invention of claim 7, the flexibility can be further improved.

According to the invention of claim 8, the flame retardancy can be further enhanced.

According to the invention of claim 9, excellent flame retardancy can be imparted to the epoxy resin composition for printed wiring boards without containing halogen. In addition, since the aluminum alkylphosphinate represented by the structural formula (5) has a high phosphorus content, it can exhibit an excellent flame retardant effect even if the blending amount is small. In addition, when the alkyl group in the chemical structure of the aluminum alkylphosphinate has a low molecular weight, the aluminum alkylphosphinate behaves in the same manner as an inorganic filler, and therefore, a decrease in glass transition temperature (Tg) is suppressed. The high heat resistance and chemical resistance of the epoxy resin composition for boards can be maintained. Furthermore, by containing a carbodiimide-modified soluble polyamide, the insulating property of the epoxy resin composition for printed wiring boards is improved, and the flame retardancy, heat resistance and chemical resistance are further improved, and in addition to the inorganic filler. In spite of containing the aluminum aluminum phosphinate that behaves, the epoxy resin composition for printed wiring board is imparted with excellent flexibility and can maintain high flexibility. Thus, the flame retardancy can be further enhanced as compared with the case of using other phosphorus flame retardants.

According to the invention of claim 10, the epoxy resin composition for a printed wiring board can exhibit particularly excellent flame retardancy, and further the reduction of the glass transition temperature (Tg) is further suppressed, and the printed wiring board. The high flexibility of the epoxy resin composition can be sufficiently maintained. That is, flame retardancy and flexibility can be further improved.

According to the solder resist composition according to the eleventh aspect of the present invention, it is possible to improve all of adhesiveness, flexibility and fillability.

According to the resin film of the twelfth aspect of the present invention, it is possible to improve all of adhesion, flexibility, and fillability.

According to the resin sheet according to claim 13 of the present invention, it is possible to improve all of adhesion, flexibility, and fillability.

According to the prepreg according to claim 14 of the present invention, it is possible to improve all of adhesion, flexibility, and fillability.

According to the metal foil with a resin according to the fifteenth aspect of the present invention, it is possible to improve all of adhesion, flexibility, and fillability.

According to the metal foil with a resin according to claim 16 of the present invention, it is possible to improve all of adhesion, flexibility, filling property and dimensional stability.

According to the coverlay according to claim 17 of the present invention, it is possible to improve all of adhesion, flexibility and filling properties.

According to the coverlay according to claim 18 of the present invention, it is possible to improve all of adhesion, flexibility and filling properties.

According to the flexible printed wiring board of the nineteenth aspect of the present invention, it is possible to improve all of adhesion, flexibility, and filling properties.

An example of the metal foil with resin which concerns on this invention is shown, (a) (b) is sectional drawing.

DESCRIPTION OF SYMBOLS 1 Epoxy resin composition for printed wiring boards 2 Coated material 3 Film-like material 4 Insulating layer 5 Metal foil

Hereinafter, embodiments of the present invention will be described.

In the present invention, the epoxy resin composition for a printed wiring board contains (A) an epoxy resin, (B) an epoxy resin curing agent, and (C) a carbodiimide-modified soluble polyamide as essential components.

As the epoxy resin as the component (A), for example, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, oxidation type epoxy resin and the like can be used. Among these, examples of the glycidyl ether type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, alcohol type epoxy resin and the like. Examples of the glycidyl ester type epoxy resin include hydrophthalic acid type epoxy resins and dimer acid type epoxy resins. Examples of the glycidylamine type epoxy resin include aromatic amine type epoxy resins and aminophenol type epoxy resins. Moreover, as an oxidation type epoxy resin, an alicyclic epoxy resin etc. can be illustrated. Furthermore, an epoxy resin having a naphthalene skeleton, a novolac type epoxy resin having a phenol skeleton and a biphenyl skeleton (biphenyl novolac epoxy resin), a phosphorus-modified epoxy resin (described later), etc. can be used, but one containing no halogen is used. preferable. In particular, as the component (A), it is preferable to use an epoxy resin having a naphthalene skeleton. When such an epoxy resin is used, the heat resistance, migration resistance, and chemical resistance of the flexible printed wiring board can be improved. Among these, as the epoxy resin having a naphthalene skeleton, it is preferable to use at least one of those represented by the structural formulas (1) to (3). When such an epoxy resin is used, the heat resistance, migration resistance, and chemical resistance of the flexible printed wiring board can be further enhanced as compared with the case of using other epoxy resins.

As the epoxy resin curing agent as component (B), for example, polyamines, modified polyamines, acid anhydrides, hydrazine derivatives, polyphenols, and the like can be used. Among these, examples of the polyamine-based curing agent include aliphatic polyamines, alicyclic polyamines, and aromatic polyamines. Of these, examples of the aliphatic polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, and diethylaminopropylamine. Examples of the alicyclic polyamines include isophorone diamine, 1,3-bisaminomethylcyclohexane, bis (4-aminocyclohexyl) methane, norbornene diamine, 1,2-diaminocyclohexane, and laromine. Examples of aromatic polyamines include diaminodiphenylmethane, metaphenylenediamine, and diaminodiphenylsulfone. Examples of acid anhydrides include hexahydrophthalic anhydride, methyl tetrahydro anhydride, methyl hexahydrophthalic anhydride, methyl nadic acid anhydride, hydrogenated methyl nadic acid anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexene tetracarboxylic acid. Examples include dianhydride, trimellitic anhydride, pyromellitic acid free, benzophenone tetracarboxylic dianhydride, aliphatic dibasic acid polyanhydride, and the like. Examples of the polyphenol-based curing agent include phenol novolak, xylene novolak, bis A novolak, triphenylmethane novolak, biphenyl novolak, dicyclopentadienephenol novolak, and terpene phenol novolak. Further, aminotriazine novolac resins, novolac-type phenol resins and the like can be used. In particular, as the component (B), it is preferable to use at least one of aminotriazine novolak resin and dicyandiamide represented by the structural formula (4). When such an epoxy resin curing agent is used, long-term product storage stability (B-stage storage stability) of a resin film, prepreg, and resin-attached metal foil (resin sheet with metal foil) can be enhanced and flexible. The flame retardancy and chemical resistance of the printed wiring board can be improved. The content of component (B) is preferably 10 to 45% by mass with respect to the total amount of components (A), (B) and (C).

As the carbodiimide-modified soluble polyamide as component (C), it is possible to use a product obtained by reacting a soluble polyamide and a carbodiimide compound at a reaction temperature of 50 to 250 ° C. in the presence or absence of a solvent. it can.

The soluble polyamide is completely dissolved in an amount of 1 part by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass or more with respect to 100 parts by mass of a mixture of alcohol and aromatic and / or ketone organic solvents. It is possible.

Examples of the alcohol include methanol, ethanol, isopropyl alcohol and the like. Examples of the aromatic solvent include benzene and toluene. Examples of the ketone solvent include cyclohexanone. , 2-butanone, cyclopentanone and the like. These alcohols, aromatic solvents and ketone solvents preferably have a boiling point of 130 ° C. or lower.

Soluble polyamide can be obtained by solubilizing polyamide. As the solubilization method, for example, a method in which hydrogen atoms of amide bonds of various polyamides are partially substituted with methoxymethyl groups can be exemplified. When a methoxy group is introduced into a polyamide, the hydrogen bonding ability of the amide group is lost, and the crystallinity of the polyamide is inhibited, so that the solubility in a solvent is increased. Examples of the solubilization method include a method of introducing a polyether or polyester into a polyamide molecule before solubilization to obtain a copolymer. Examples of the polyamide before solubilization include nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, and nylon 46.

Specific examples of the soluble polyamide include “Zytel 61” (manufactured by DuPont), “Versalon” (manufactured by General Mills), “Amilan CM4000” (manufactured by Toray Industries, Inc.), and “Amilan CM8000” (manufactured by Toray Industries, Inc.). , “PA-100” (manufactured by Fuji Kasei Kogyo Co., Ltd.), “Toresin” (manufactured by Nagase ChemteX Corporation), and the like.

The carbodiimide compound is a compound having one or more carbodiimide groups in the molecule, and examples thereof include a monocarbodiimide compound and a polycarbodiimide compound. For example, an organic phosphorus compound or an organometallic compound is used as a catalyst. Isocyanates can be synthesized by a decarboxylation condensation reaction at a temperature of about 70 ° C. or higher in a solvent-free or inert solvent.

Examples of the monocarbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β-naphthylcarbodiimide and the like. Among these, dicyclohexylcarbodiimide or diisopropylcarbodiimide is preferable from the viewpoint of industrial availability.

In addition, as the polycarbodiimide compound, those produced by various methods can be used, but basically, a conventional method for producing polycarbodiimide (for example, US Pat. No. 2,941,956, J. Org). Chem. 28, 2069-2075 (1963), Chemical Review 1981, Vol. 81 No. 4, p619-621) can be used.

Examples of the organic diisocyanate that is a synthetic raw material for producing the polycarbodiimide compound include aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and mixtures thereof. Specifically, 1,5- Naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate , Mixtures of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophor Diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate, 2,6-diisopropylphenyl diisocyanate, 1,3,5-triisopropylbenzene-2,4-diisocyanate, etc. be able to.

Of these, aliphatic (including alicyclic) organic diisocyanates are preferable from the viewpoint of improving flexibility and moisture resistance, and particularly ilophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, tetramethylxylylene diene. Isocyanates and mixtures thereof are more preferred.

Also, when the polycarbodiimide compound is produced, the polymerization reaction can be stopped halfway by cooling or the like to control the polymerization degree to an appropriate level. In this case, the terminal is an isocyanate group. Furthermore, in order to control to an appropriate degree of polymerization, there is a method of sealing all or part of the remaining terminal isocyanate groups using a compound that reacts with the terminal isocyanate group of the polycarbodiimide compound, such as a monoisocyanate compound. . By controlling the degree of polymerization, compatibility with soluble polyamide and storage stability can be enhanced, which is preferable in terms of quality improvement.

Examples of the monoisocyanate compound for sealing the end of such a polycarbodiimide compound and controlling the degree of polymerization thereof include phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, naphthyl isocyanate and the like. be able to.

Further, the end-capping agent that seals the end of the polycarbodiimide compound and controls the degree of polymerization thereof is not limited to the monoisocyanate compound, but an active hydrogen compound that can react with an isocyanate group, for example, ( i) an aliphatic, aromatic or alicyclic compound having an —OH group, methanol, ethanol, phenol, cyclohexanol, N-methylethanolamine, polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether; (ii) = Diethylamine having a NH group, dicyclohexylamine; (iii) butylamine having a NH ₂ group, cyclohexylamine; (iv) succinic acid, benzoic acid, cyclohexane acid having a -COOH group; (v) ethyl having a SH group Mercaptans, ants Lumercaptan, thiophenol; (vi) compounds having an epoxy group; (vii) acid anhydrides such as acetic anhydride, methyltetrahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

The decarboxylation condensation reaction of the organic diisocyanate is performed in the presence of a suitable carbodiimidization catalyst. Examples of the carbodiimidization catalyst that can be used include organic phosphorus compounds, organometallic compounds [general formula M- (OR) _n [M is titanium (Ti), sodium (Na), potassium (K), vanadium (V), tungsten (W), hafnium (Hf), zirconium (Zr), lead (Pb), manganese (Mn), nickel (Ni), calcium (Ca), barium (Ba), etc., R represents an alkyl group or aryl group having 1 to 20 carbon atoms, and n represents a valence of M] From the viewpoint of activity, phospholene oxides are preferable for organophosphorus compounds, and titanium, hafnium and zirconium are preferred for organometallic compounds. Rukokishido are preferred.

Specific examples of the phosphorene oxides include 3-methyl-1-phenyl-2-phospholene-1-oxide, 3-methyl-1-ethyl-2-phospholene-1-oxide, 1,3- Dimethyl-2-phospholene-1-oxide, 1-phenyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 1-methyl-2-phospholene-1-oxide or a double thereof Examples of the bonding isomers are 3-methyl-1-phenyl-2-phospholene-1-oxide, which is easily available industrially.

The carbodiimide compound is not particularly limited as long as it has one or more carbodiimide groups in the molecule having the functions as described above. In view of this, polycarbodiimide compounds having two or more carbodiimide groups in the molecule, such as 4,4′-dicyclohexylmethanecarbodiimide, are preferred, and aliphatic or alicyclic polycarbodiimide compounds are more preferred. The degree of polymerization is preferably 2 to 30, and more preferably 2 to 20. A polymerization degree of 2 or more is preferable from the viewpoint of heat resistance, and a polymerization degree of 20 or less is preferable from the viewpoint of compatibility.

The carbodiimide-modified soluble polyamide as component (C) is obtained by reacting the soluble polyamide with a carbodiimide compound in the presence or absence of a solvent, and reactive functional groups such as a carboxyl group and an amino group that the soluble polyamide has, and It can be obtained by reacting a carbodiimide group or an isocyanate group of a carbodiimide compound that can react with the carboxylic acid.

The method of reacting the soluble polyamide and the carbodiimide compound is not particularly limited, but can be performed in the presence or absence of a solvent.

Examples of the method of reacting in the presence of a solvent include a method of reacting after dissolving a soluble polyamide and a carbodiimide compound in a solvent, and a method of reacting by heating and stirring the soluble polyamide and the carbodiimide compound is preferable. A method in which a carbodiimide compound is added to a solution obtained by dissolving a soluble polyamide in a solvent and reacted by heating and stirring under reflux is more preferable. The carbodiimide-modified soluble polyamide can be obtained by removing the solvent from the solution thus obtained under normal pressure or reduced pressure.

As a method of reacting in the absence of a solvent, for example, a method in which a soluble polyamide is melted to a melting point or higher and then mixed and reacted, or a soluble polyamide and a carbodiimide compound are melted and kneaded by a twin screw extruder. The method of making it react can be mentioned.

When reacting a soluble polyamide and a carbodiimide compound, it is preferable that the reaction system does not contain a compound that inhibits carbodiimide modification, and the reaction system contains only a carbodiimide compound, a soluble polyamide, and a solvent used as necessary. Is more preferable. Specific examples of the compound that inhibits the carbodiimide modification include an epoxy resin, an amine resin, a melamine resin, and a phenol resin.

The time for reacting the soluble polyamide with the carbodiimide compound varies depending on the type of the soluble polyamide and carbodiimide compound used, the reaction method, the reaction temperature, etc., but is, for example, about 1 to 500 minutes, and 5 to 200 minutes. preferable.

The temperature at which the soluble polyamide reacts with the carbodiimide compound also varies depending on the type of soluble polyamide or carbodiimide compound used, the reaction method, the reaction temperature, etc., but is, for example, 50 to 250 ° C. When the reaction is carried out in the presence, it is preferably 50 to 150 ° C, more preferably 70 to 130 ° C. In addition, when the soluble polyamide and the carbodiimide compound are reacted in the absence of a solvent, the temperature is preferably 130 to 250 ° C, more preferably 150 to 220 ° C. If the reaction temperature is less than 50 ° C, the reaction between the soluble polyamide and the carbodiimide compound is slow, and it takes time to modify the soluble polyamide, which is not industrially preferable. If the reaction temperature exceeds 250 ° C, deterioration due to decomposition of the resin is likely to occur. Become.

In addition, by reacting soluble polyamide and a carbodiimide compound as described above, the soluble polyamide is modified to become a carbodiimide-modified soluble polyamide. For example, as the above reaction proceeds, the carbodiimide group of the carbodiimide compound decreases, so when comparing the reaction product with the product by infrared measurement, the peak of the carbodiimide group observed in the reaction product decreases. is doing. In addition, when differential thermogravimetric measurement is performed on the reactant and product, multiple endothermic peaks of the reactant, such as amide resin and carbodiimide resin, are observed, but the endothermic peaks of the product are aggregated into one. The From the above, it can be confirmed that the soluble polyamide has been modified.

The carbodiimide-modified soluble polyamide obtained as described above is excellent in storage stability as compared with a composition comprising a soluble polyamide and a carbodiimide compound. That is, in the case of the above composition, thickening of the solution occurs when it is made into a solution, and further gelation is achieved, whereas the modified one shows no change such as thickening even in the solution state. And can be stored for a long time.

The amount of the carbodiimide compound added is preferably 0.5 to 20 parts by mass, and more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the soluble polyamide. Thereby, while being able to fully improve moisture resistance and heat resistance, it can prevent that plasticity becomes high too much or impact resistance is impaired. If the addition amount is less than 0.5 parts by mass, the moisture resistance and heat resistance may not be sufficiently improved, and if it exceeds 20 parts by mass, the plasticity may become too high or the impact resistance may be impaired. is there.

The content of the carbodiimide-modified soluble polyamide as the component (C) is preferably 20 to 70% by mass with respect to the total amount of the components (A), (B), and (C). When the content of the component (C) is within this range, the flexibility and chemical resistance of the flexible printed wiring board can be improved. However, if the content of the component (C) is less than 20% by mass, the flexibility may be lowered. Conversely, if the content of the component (C) exceeds 70% by mass, flame retardancy and heat resistance are likely to occur. May decrease.

In addition to the components (A), (B), and (C), the epoxy resin composition for printed wiring boards preferably contains a phenoxy resin. As the phenoxy resin, bisphenol A type phenoxy resin, bisphenol A / bisphenol F type copolymer phenoxy resin, phosphorus-modified phenoxy resin (described later), and the like can be used. This phenoxy resin can further enhance the flexibility of the flexible printed wiring board. The content of the phenoxy resin is preferably 5 to 30% by mass with respect to the total amount of the epoxy resin composition for printed wiring boards.

Furthermore, it is preferable that the epoxy resin composition for printed wiring boards contains at least one of phosphorus-based flame retardants such as phosphorus-modified epoxy resin, phosphorus-modified phenoxy resin, and phosphazene. Here, as the phosphorus-modified epoxy resin, for example, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 1,4-naphthoquinone are reacted, and cresol novolac resin is further reacted. What was obtained can be used. In addition, as the phosphorus-modified phenoxy resin, one having a molecular skeleton mainly composed of phenoxy resin and containing several phosphorus elements (for example, about 1 to 5) in 1 mol of phosphorus-containing phenoxy resin is used. Can do. As the phosphorus-based flame retardant, in addition to phosphazene, for example, monomeric phosphate ester, condensed phosphate ester, reactive phosphorus flame retardant, phosphate, phosphazene compound, and the like can be used. Among these, the monomeric phosphate esters include triphenyl phosphate, tricresyl phosphate, trixinyl phosphate, triethyl phosphate, cresyl diphenyl phosphate, xylyl diphenyl phosphate, cresyl bis (di-2,6-xylenyl) phosphate, 2- Examples thereof include ethylhexyl diphenyl phosphate. Examples of the condensed phosphate ester include resorcinol bis (diphenyl) phosphate, bisphenol A bis (diphenyl) phosphate, bisphenol A bis (dicresyl) phosphate, resorcinol bis (di-2,6-xylenyl) phosphate, and the like. it can. Examples of reactive phosphorus flame retardants include bisphenol A bisphenyl phosphate, 9,10-dihydro-9-oxa-10-phosphenanthrene-10-oxide, and 2- (diphenylphosphinyl) hydroquinone. can do. Examples of the phosphate include melamine phosphate, dimelamine phosphate, melamine pyrophosphate, dimelamine pyrophosphate, melamine polyphosphate, and ethylenediamine phosphate. Examples of the phosphazene compound include phosphonitrile phenyl ester, cyanophenol / phenol mixed substituted cyclophosphazene, phosphonitrile chloride / hydroquinone / phenol condensate, and the like. By using such a thing, a flame retardance can further be improved. The total content of the phosphorus-modified epoxy resin, phosphorus-modified phenoxy resin, and phosphorus flame retardant is preferably 10 to 40% by mass with respect to the total amount of the epoxy resin composition for printed wiring boards.

In particular, as the phosphorus-based flame retardant, it is preferable to use aluminum alkylphosphinate represented by the above structural formula (5). This aluminum alkylphosphinate is halogen-free and has a high phosphorus content, so that it can exhibit an excellent flame retardant effect even if the blending amount is small. In addition, when the alkyl group in the chemical structure of the aluminum alkylphosphinate has a low molecular weight, the aluminum alkylphosphinate behaves in the same manner as an inorganic filler, thereby suppressing the decrease in glass transition temperature (Tg). is there. In addition, although it contains the above-described aluminum aluminum phosphinate that behaves like an inorganic filler, the epoxy resin composition for printed wiring boards also contains a carbodiimide-modified soluble polyamide at the same time. A decrease in flexibility of the resin composition is suppressed, and high flexibility is maintained. In this aluminum alkylphosphinate, the carbon number of the alkyl group represented by R ₁ and R ₂ in the structural formula (5) is preferably in the range of 1-6. When such a phosphorus flame retardant is used, the flame retardancy can be further enhanced as compared with the case where other phosphorus flame retardants are used. In particular, when the above-mentioned aluminum alkylphosphinate is used as the phosphorus flame retardant, the content thereof is preferably 5 to 20% by mass with respect to the total amount of the components (A), (B) and (C). When the content of the aluminum alkylphosphinate is within this range, the flame retardancy and flexibility of the flexible printed wiring board can be further enhanced. That is, if the content of the aluminum alkylphosphinate is 5% by mass or more, even if the epoxy resin composition for a printed wiring board contains only the aluminum alkylphosphinate as a flame retardant, the printed wiring Particularly excellent flame retardancy is imparted to the epoxy resin composition for boards. Moreover, if content of the said aluminum alkylphosphinate is 20 mass% or less, the high softness | flexibility of the epoxy resin composition for printed wiring boards is fully maintained.

If the flame retardant compounded in the epoxy resin composition for printed wiring boards is only the above-mentioned aluminum alkylphosphinate, the action of suppressing the decrease in glass transition temperature (Tg) is remarkable. Moreover, you may make the epoxy resin composition for printed wiring boards contain organic phosphorus compounds, such as phosphate ester, as flame retardants other than the said alkylphosphinic acid aluminum. The organophosphorus compound causes a decrease in the glass transition temperature (Tg) of the epoxy resin composition for a printed wiring board, but the decrease in the glass transition temperature (Tg) is alleviated by using the above aluminum alkylphosphinate together. It is desirable that the amount of the flame retardant other than the aluminum alkylphosphinate is appropriately adjusted so that sufficient flame retardancy is ensured and a decrease in the glass transition temperature (Tg) is sufficiently suppressed.

The epoxy resin composition for printed wiring boards contains the components (A), (B), and (C) as essential components, and further includes phenoxy resin, phosphorus-modified epoxy resin, phosphorus-modified phenoxy resin, phosphorus flame retardant, 2- It can be prepared by blending a curing accelerator such as ethyl-4-methylimidazole as an optional component.

In the epoxy resin composition for a printed wiring board thus obtained, the carbodiimide-modified soluble polyamide obtained by reacting an unreacted group (amino group or carboxyl group) of polyamide with carbodiimide is used as an epoxy resin or epoxy. By blending with a resin curing agent, storage stability, adhesion, flexibility, and filling properties can all be improved. That is, by reacting unreacted groups (amino group and carboxyl group) originating from the raw material of polyamide with carbodiimide, the reaction between the polyamide resin and the epoxy resin is prevented from being promoted at a low temperature, the varnish storage stability is maintained, and the coating is performed. Storage stability and press moldability of various sheets (resin film, resin sheet, prepreg, metal foil with resin, coverlay, etc., described later) obtained by processing and drying can be satisfied. And the varnish and sheet workability and processability (storage stability and press formability) of the epoxy resin composition for printed wiring boards, and various characteristics (adhesion, flexibility, fillability, etc.) of the flexible printed wiring board It can be made compatible.

In particular, in the epoxy resin composition for printed wiring boards containing the aluminum alkylphosphinate represented by the structural formula (5), excellent flame retardancy can be imparted without containing halogen. Is something that can be done. Moreover, since this aluminum alkylphosphinate has a high phosphorus content, it can exhibit an excellent flame retardant effect even if the blending amount is small. In addition, when the alkyl group in the chemical structure of the aluminum alkylphosphinate has a low molecular weight, the aluminum alkylphosphinate behaves in the same manner as an inorganic filler, and therefore, a decrease in glass transition temperature (Tg) is suppressed. The high heat resistance and chemical resistance of the epoxy resin composition for boards are maintained. Furthermore, by containing a carbodiimide-modified soluble polyamide, the insulating property of the epoxy resin composition for printed wiring boards is improved, and the flame retardancy, heat resistance and chemical resistance are further improved, and in addition to the inorganic filler. In spite of containing the aluminum aluminum phosphinate that behaves, the epoxy resin composition for printed wiring board is imparted with excellent flexibility and can maintain high flexibility.

Using the epoxy resin composition for printed wiring boards as a varnish as appropriate, a sheet of a solder resist composition, a resin film, a resin sheet, a prepreg, a resin-attached metal foil, a coverlay, etc. can be produced. It is possible to manufacture a flexible printed wiring board.

That is, an epoxy resin composition whose viscosity is adjusted by blending an appropriate organic solvent as required can be used as a solder resist composition.

The resin film can be produced by forming an epoxy resin composition for a printed wiring board into a film and drying it by heating until it is in a semi-cured state (B stage state).

The resin sheet can be produced by molding the epoxy resin composition for a printed wiring board into a sheet shape and heating and drying it until it is in a semi-cured state (B stage state).

The prepreg can be produced by impregnating a substrate such as a glass cloth with an epoxy resin composition for a printed wiring board and heating and drying it until it is in a semi-cured state.

The metal foil with resin can be produced by applying an epoxy resin composition for a printed wiring board to a metal foil such as a copper foil and heating and drying it to form a semi-cured adhesive resin layer. .

Further, as shown in FIG. 1, the metal foil with resin is obtained by applying the epoxy resin composition 1 for a printed wiring board to a copper foil through an insulating layer 4 composed of at least one of a coated product 2 and a film-like product 3. It can also be manufactured by applying to a metal foil 5 such as the like and heating and drying to form a semi-cured adhesive resin layer 6.

That is, for example, the resin-attached metal foil shown in FIG. 1A is obtained by applying a liquid polyimide resin or the like as the coated product 2 to the surface of the metal foil 5 such as a copper foil, and further, an epoxy resin composition for a printed wiring board. It can manufacture by apply | coating the thing 1 and heat-drying this. Then, the insulating layer 4 is formed by the cured or semi-cured coated product 2, and the adhesive resin layer 6 is formed by the semi-cured epoxy resin composition 1 for a printed wiring board. Specifically, the resin-attached metal foil shown in FIG. 1A is, for example, “R-F552” (manufactured by Panasonic Electric Works Co., Ltd.). A two-layer casting flexible copper-clad laminate produced by heating and drying the coating, wherein the copper foil has a thickness of 12 μm and the cured coating 2 has a thickness of 12.5 μm) It can manufacture by apply | coating the epoxy resin composition 1 for printed wiring boards to the surface of the workpiece 2, and heat-drying this. Then, the insulating layer 4 is formed by the cured coated product 2, and the adhesive resin layer 6 having a thickness of 50 μm is formed by the semi-cured epoxy resin composition 1 for a printed wiring board. Further, the resin-attached metal foil shown in FIG. 1A is used for a printed wiring board on the surface of the film-like material 3 after pressure-bonding a polyimide film or the like as the film-like material 3 on the surface of the metal foil 5 such as a copper foil. It can also be produced by applying the epoxy resin composition 1 and drying it by heating. And the insulating layer 4 is formed with the film-form thing 3, and the adhesive resin layer 6 is formed with the epoxy resin composition 1 for printed wiring boards in a semi-hardened state.

On the other hand, the resin-coated metal foil shown in FIG. 1 (b) is obtained by applying a liquid polyimide resin or the like as the coated product 2 to the surface of the metal foil 5 such as a copper foil, and forming a polyimide film as the film-like product 3 on the coated surface. It can be manufactured by applying the epoxy resin composition 1 for a printed wiring board on the surface of the film-like product 3 and drying it by heating. Then, the insulating layer 4 is formed by the coated product 2 and the film-like product 3 in the cured or semi-cured state, and the adhesive resin layer 6 is formed by the epoxy resin composition 1 for a printed wiring board in the semi-cured state.

Thus, in the metal foil with resin shown in FIG. 1, since the adhesive resin layer 6 is formed of the epoxy resin composition for printed wiring boards, all of adhesion, flexibility and fillability are improved. Further, since the insulating layer 4 composed of at least one of the coated material 2 and the film-like material 3 is interposed between the adhesive resin layer 6 and the metal foil 5, this insulation The layer 4 can enhance dimensional stability. In addition to the liquid polyimide resin, a liquid polyetherimide resin and a polyether sulfone resin can be used as the coated product 2, and the film-like product 3 includes a polyether film and a polyether. An imide film and a polyether sulfone film can also be used. Moreover, the number of layers and the order of the coated product 2 and the film-like product 3 that form the insulating layer 4 are not particularly limited.

Moreover, a coverlay can be manufactured by apply | coating the epoxy resin composition for printed wiring boards to the surface of plastic sheets, such as a polyimide film, and heat-drying this and forming the adhesive resin layer of a semi-hardened state. .

Also, the metal foil with resin can be used as a coverlay having a shielding function.

Further, the flexible printed wiring board is formed using at least one of a solder resist composition, a resin film, a resin sheet, a prepreg, a resin-attached metal foil, and a coverlay.

Specifically, for example, a flexible printed wiring board is manufactured by forming a circuit on one side or both sides of a polyimide film or the like, and a solder resist composition is applied to the circuit forming surface of the flexible printed wiring board in a pattern. By heating and forming a film, a flexible printed wiring board having a solder resist film can be produced.

In addition, using polyimide film or the like as a core material, after laminating any one of resin film, resin sheet, prepreg, and metal foil with resin on one or both sides of this core material, circuit formation and interlayer connection as appropriate By performing this, a flexible printed wiring board can be manufactured. Moreover, a multilayer flexible printed wiring board can also be manufactured by sequentially repeating the lamination of these resin films, resin sheets, prepregs, or resin-attached metal foils, circuit formation, interlayer connection, and the like.

In addition, a flexible printed wiring board having a cover lay can be manufactured by overlaying an adhesive resin layer of a cover lay on the circuit forming surface of the flexible printed wiring board and heating and curing the adhesive resin layer as necessary. it can.

In the solder resist composition, resin film, resin sheet, prepreg, resin-attached metal foil, coverlay, and flexible printed wiring board obtained in this manner, any of the above epoxy resin compositions for printed wiring boards is used as a material. Therefore, it is possible to improve adhesion, flexibility, and filling properties. Furthermore, since the reaction between the epoxy group and the carbodiimide group also proceeds during high-temperature press molding, a flexible printed wiring board having excellent heat resistance and chemical resistance can be obtained. In addition, the metal foil with resin can be used as a build-up insulating sheet similarly to a bonding sheet or a cover lay, and can also be used as a cover lay having a shielding function.

In addition, a solder resist composition, a resin film, a resin sheet, a prepreg, and a resin formed using, as a material, an epoxy resin composition for a printed wiring board containing the aluminum alkylphosphinate represented by the structural formula (5) above. In the case of metal foils, coverlays, and flexible printed wiring boards, excellent flame retardancy can be imparted without using halogen. Further, the aluminum alkylphosphinate behaves in the same manner as an inorganic filler, and therefore, a decrease in glass transition temperature (Tg) is suppressed, and high heat resistance and chemical resistance are maintained. Furthermore, by using a carbodiimide-modified soluble polyamide, the insulating properties are improved, and the flame retardant, heat resistance, and chemical resistance are further improved, and the above-described aluminum alkylphosphinate that behaves like an inorganic filler is used. Nevertheless, excellent flexibility is imparted and high flexibility can be maintained. Thus, the carbodiimide-modified soluble polyamide can improve all of adhesion, flexibility, and fillability, and further the reaction between the epoxy group and the carbodiimide group during high-temperature press molding, A flexible printed wiring board having excellent chemical resistance and the like can be obtained.

Hereinafter, the present invention will be specifically described by way of examples.

(Synthesis of carbodiimide compounds)
By reacting 590 g of 4,4′-dicyclohexylmethane diisocyanate, 62.6 g of cyclohexyl isocyanate and 6.12 g of carbodiimidization catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide) at 180 ° C. for 48 hours, As a carbodiimide compound, 4,4′-dicyclohexylmethane carbodiimide resin (degree of polymerization = 10) was obtained.

((C) Synthesis of carbodiimide-modified soluble polyamide)
In a 1-liter separable flask, 50.0 g of ester copolymerized amide resin (trade name: “CM8000”, manufactured by Toray Industries, Inc.) and 450.0 g of a mixed solvent of isopropyl alcohol and toluene (mass mixing ratio 4: 6) are added. In addition, it was dissolved by stirring. To the solution thus obtained, 5.0 g of the above carbodiimide compound (4,4′-dicyclohexylmethanecarbodiimide resin) was added, the flask was immersed in an oil bath at 120 ° C., heated and stirred for 3 hours under reflux, and then dried under reduced pressure. Then, by removing the solvent, a carbodiimide-modified soluble polyamide serving as component (C) was obtained.

When the infrared spectrophotometric measurement was performed on the (C) carbodiimide-modified soluble polyamide obtained as described above, an absorption peak indicating the presence of a carbodiimide group was observed at 2120 cm ⁻¹ . Further, when differential scanning calorimetry was performed on the (C) carbodiimide-modified soluble polyamide, one endothermic peak was observed. The (C) carbodiimide-modified soluble polyamide had a glass transition temperature (Tg) of 120 ° C., a 5% weight loss temperature of 320 ° C., and a solution viscosity of 860 mPa · s.

Next, varnishes of the epoxy resin compositions for printed wiring boards of Examples 1 to 14 and Comparative Examples 1 and 2 were prepared according to the composition shown in Table 1 below. In addition, all the mixing | blendings of following Table 1 are solid content ratios.

Example 1
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (1)), (B) epoxy resin curing agent (aminotriazine novolak resin represented by the above structural formula (4)), (C ) A varnish of an epoxy resin composition for a printed wiring board having a solid content of 33% by mass was prepared by mixing a carbodiimide-modified soluble polyamide, a curing accelerator, and a phosphorus-based flame retardant (phosphazene) in a container.

(Example 2)
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (1)), (B) epoxy resin curing agent (aminotriazine novolak resin represented by the above structural formula (4)), (C ) A varnish of an epoxy resin composition for a printed wiring board having a solid content of 33% by mass was prepared by mixing a carbodiimide-modified soluble polyamide, a curing accelerator, and a phosphorus-based flame retardant (phosphazene) in a container.

(Example 3)
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (1)), (B) epoxy resin curing agent (aminotriazine novolak resin represented by the above structural formula (4)), (C ) A varnish of an epoxy resin composition for a printed wiring board having a solid content of 27% by mass was prepared by mixing a carbodiimide-modified soluble polyamide, a curing accelerator, and a phosphorus-based flame retardant (phosphazene) in a container.

Example 4
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (1)), (B) epoxy resin curing agent (aminotriazine novolak resin represented by the above structural formula (4)), (C ) A varnish of an epoxy resin composition for a printed wiring board having a solid content of 25% by mass was prepared by mixing a carbodiimide-modified soluble polyamide, a curing accelerator, and a phosphorus-based flame retardant (phosphazene) in a container.

(Example 5)
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (1)), (B) epoxy resin curing agent (aminotriazine novolak resin represented by the above structural formula (4)), (C ) A varnish of an epoxy resin composition for a printed wiring board having a solid content of 19% by mass was prepared by mixing a carbodiimide-modified soluble polyamide, a curing accelerator, and a phosphorus flame retardant (phosphazene) in a container.

(Example 6)
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (1)), (B) epoxy resin curing agent (aminotriazine novolak resin represented by the above structural formula (4)), (C ) A varnish of an epoxy resin composition for a printed wiring board having a solid content of 27% by mass was prepared by mixing a carbodiimide-modified soluble polyamide, a curing accelerator, and a phosphorus-based flame retardant (phosphazene) in a container.

(Example 7)
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (1)), (B) epoxy resin curing agent (aminotriazine novolak resin represented by the above structural formula (4)), (C ) A varnish of an epoxy resin composition for printed wiring boards having a solid content of 29% by mass was prepared by mixing a carbodiimide-modified soluble polyamide, a phenoxy resin, a curing accelerator, and a phosphorus flame retardant (phosphazene) in a container.

(Example 8)
(A) epoxy resin (biphenyl novolac epoxy resin), (B) epoxy resin curing agent (aminotriazine novolac resin represented by the above structural formula (4)), (C) carbodiimide-modified soluble polyamide, curing accelerator, phosphorus-based A varnish of an epoxy resin composition for printed wiring boards having a solid content of 27% by mass was prepared by mixing a flame retardant (phosphazene) in a container.

Example 9
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (1)), (B) epoxy resin curing agent (novolak type phenol resin), (C) carbodiimide-modified soluble polyamide, curing accelerator, A phosphorus flame retardant (phosphazene) was put in a container and mixed to prepare a varnish of an epoxy resin composition for a printed wiring board having a solid content of 27% by mass.

(Example 10)
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (2)), (B) epoxy resin curing agent (aminotriazine novolak resin represented by the above structural formula (4)), (C ) A varnish of an epoxy resin composition for a printed wiring board having a solid content of 22% by mass was prepared by mixing a carbodiimide-modified soluble polyamide, a curing accelerator, and a phosphorus-based flame retardant (phosphazene) in a container.

(Example 11)
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (3)), (B) epoxy resin curing agent (aminotriazine novolac resin represented by the above structural formula (4)), (C ) A varnish of an epoxy resin composition for a printed wiring board having a solid content of 22% by mass was prepared by mixing a carbodiimide-modified soluble polyamide, a curing accelerator, and a phosphorus-based flame retardant (phosphazene) in a container.

Example 12
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (1)), (B) epoxy resin curing agent (aminotriazine novolak resin represented by the above structural formula (4)), (C ) Prepare varnish of epoxy resin composition for printed wiring board with a solid content of 26% by mass by mixing carbodiimide-modified soluble polyamide, curing accelerator, phosphorus flame retardant (phosphazene) and phosphorus-modified epoxy resin in a container. did.

(Example 13)
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (1)), (B) epoxy resin curing agent (aminotriazine novolak resin represented by the above structural formula (4)), (C ) Prepare varnish of epoxy resin composition for printed wiring board having a solid content of 26 mass% by mixing carbodiimide-modified soluble polyamide, curing accelerator, phosphorus flame retardant (phosphazene), and phosphorus-modified phenoxy resin in a container. did.

(Example 14)
(A) Epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (1)), (B) epoxy resin curing agent (dicyandiamide), (C) carbodiimide-modified soluble polyamide, curing accelerator, phosphorus-based difficulty A varnish of an epoxy resin composition for printed wiring boards having a solid content of 28% by mass was prepared by mixing a flame retardant (phosphazene) in a container.

(Comparative Example 1)
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (1)), (B) epoxy resin curing agent (aminotriazine novolak resin represented by the above structural formula (4)), soluble polyamide A varnish of an epoxy resin composition for printed wiring boards having a solid content of 26% by mass was prepared by mixing a curing accelerator and a phosphorus-based flame retardant (phosphazene) in a container.

(Comparative Example 2)
(A) epoxy resin (epoxy resin having a naphthalene skeleton represented by the above structural formula (1)), (B) epoxy resin curing agent (aminotriazine novolak resin represented by the above structural formula (4)), soluble polyamide A varnish of an epoxy resin composition for a printed wiring board having a solid content of 22% by mass was prepared by mixing a curing accelerator in a container.

In addition, each component shown in the following Table 1 is as follows.

(A) Epoxy resin having a naphthalene skeleton (Structural Formula (1)): Epoxy resin having no naphthalene skeleton and containing a naphthalene skeleton (“NC-7000L” manufactured by Nippon Kayaku Co., Ltd., with the above structural formula (1)) Represented)
(A) Epoxy resin having naphthalene skeleton (Structural Formula (2)): Epoxy resin having no naphthalene skeleton and containing naphthalene skeleton (“EXA-9900” manufactured by DIC Corporation, represented by the above structural formula (2)) Stuff)
(A) Epoxy resin having naphthalene skeleton (structural formula (3)): Epoxy resin not containing halogen and having naphthalene skeleton (“HP-4700” manufactured by DIC Corporation, represented by the above structural formula (3)) Stuff)
(A) Biphenyl novolac epoxy resin: novolac type epoxy resin containing no phenol and having a phenol skeleton and a biphenyl skeleton (“NC-3000” manufactured by Nippon Kayaku Co., Ltd.)
(A) Phosphorus-modified epoxy resin: Phosphorus-modified epoxy resin (“FX-305EK70” manufactured by Tohto Kasei Co., Ltd.), which was dissolved in methyl ethyl ketone, and the resin solid content was 70% by mass.

(B) Phenol novolac type aminotriazine novolak resin (Structural Formula (4), R = H): Phenol novolac type aminotriazine novolak resin (“LA-7052” manufactured by DIC Corporation), represented by the above structural formula (4) And R is H), which was dissolved in methyl ethyl ketone, and the resin solid content was 60% by mass.

(B) Cresol novolac-type aminotriazine novolak resin (Structural Formula (4), R = CH ₃ ): Cresol novolac-type aminotriazine novolak resin (“LA-3018-50P” manufactured by DIC Corporation, the above structural formula (4) And R is CH ₃ ), dissolved in propylene glycol monomethyl ether, and the resin solid content was 50% by mass.

(B) Novolak type phenol resin: phenol novolak resin (manufactured by DIC Corporation, “TD-2090-60M”) dissolved in methyl ethyl ketone, and the resin solid content was 60% by weight.

(B) Dicyandiamide (C) Carbodiimide-modified soluble polyamide: The one synthesized as described above was used. In addition, this was melt | dissolved in the mixed solvent (mass mixing ratio 4: 6) of isopropyl alcohol and toluene, and solid content concentration was 11 mass%.

(C) Soluble polyamide: ester copolymer amide resin (“CM-8000” manufactured by Toray Industries, Inc.), which is dissolved in a mixed solvent of isopropyl alcohol and toluene (mass mixing ratio 4: 6). The solid content concentration was 10% by mass.

• Phenoxy resin: Phenoxy resin (“YP-50” manufactured by Toto Kasei Co., Ltd.), which was dissolved in methyl ethyl ketone, and the resin solid content was 65% by mass.

Curing accelerator: 2-ethyl-4-methylimidazole (“2E4MZ” manufactured by Shikoku Chemicals Co., Ltd.)
Phosphazene: Phosphazene (“SPB-100” manufactured by Otsuka Chemical Co., Ltd., represented by the following structural formula (6))

Phosphorus-modified phenoxy resin: Phosphorus-modified phenoxy resin (“ERF-001M30” manufactured by Tohto Kasei Co., Ltd.), a mixed solvent of diglyme, xylene, methyl cellosolve, DMF, and toluene (mass mixing ratio 10: 5: 30: 30) 15) and the resin solid content was 30% by mass.

Next, using a comma coater and a dryer connected thereto, the varnish obtained as described above is applied to one side of a copper foil having a thickness of 12 μm and dried, and the thickness after drying is 50 μm. By forming a resin layer, a copper foil with resin (resin sheet with copper foil) was produced.

And about the said varnish, while evaluating varnish preservability, about the copper foil with a resin obtained as mentioned above, chemical resistance, copper foil peeling strength, solder heat resistance, flexibility, circuit filling property, difficulty Flammability, migration resistance, and product storage stability (B-stage storage stability) were evaluated. The preparation conditions and evaluation conditions of the samples used for each of these evaluations are as follows, and the evaluation results are shown in Table 1 below.

(Varnish preservation)
The varnish preservability is determined by measuring the initial viscosity and the viscosity after storage for 7 days at 25 ° C., and “pass” the varnish whose viscosity change was less than 10%, and “fail” the varnish changed by 10% or more. It was.

(chemical resistance)
Chemical resistance was evaluated as follows. That is, two copper foils with resin were used, the surfaces on which these adhesive resin layers were formed were bonded together, and a sample was prepared by heating and pressing at 180 ° C. for 1 hour, and then the copper foil of this sample Was removed by etching. Next, this sample was immersed in an aqueous solution of 3% by mass of sodium hydroxide and a temperature of 40 ° C. for 3 minutes and then taken out, washed with water, and sufficiently wiped off moisture with a dry clean cloth. Immediately thereafter, changes in appearance such as discoloration, swelling, and peeling of the sample were visually observed. And the thing without an external appearance change was set as "pass", and the thing with an external appearance change was set as "fail".

(Copper foil peel strength)
The copper foil peel strength was prepared by attaching a surface on which an adhesive resin layer of a copper foil with resin was formed on both sides of a polyimide film having a thickness of 25 μm, and heating and pressing at 180 ° C. for 1 hour, The copper foil of this sample was evaluated by the peel strength when peeled off in the 90 ° direction.

(Solder heat resistance)
For solder heat resistance, a sample was prepared by laminating a surface of an adhesive resin layer of a resin-coated copper foil on both sides of a polyimide film having a thickness of 25 μm, and heating and pressing at 180 ° C. for 1 hour. After immersing in a solder bath heated to 260 ° C. and 288 ° C. for 60 seconds, the appearance was evaluated. Those having no appearance abnormality such as blistering or peeling were evaluated as “pass”, and those other than this were defined as “fail”.

(Flexibility)
Flexibility was tested by the MIT method, and the measurement condition was set to be bent at a rate of R = 0.38 mm, a load of 500 g, and 175 times per minute, and evaluated by the number of times of bending until the circuit could not be conducted.

(Circuit fillability)
The circuit filling property is obtained by laminating the surface on which the adhesive resin layer of the copper foil with resin is formed on a test piece formed by providing a comb-shaped pattern on a flexible printed wiring board of rolled copper foil having a thickness of 35 μm on one side, at 180 ° C. A sample was prepared by heating and pressing for 1 hour, and the appearance of this sample was visually observed and evaluated. The pattern filled with resin was regarded as “pass”, and the other pattern was defined as “fail”.

(Flame retardance)
The flame retardancy was evaluated according to the flame retardant judgment standard of 94 VTM according to UL94.

(Migration resistance)
Migration resistance is achieved by bonding the surface on which the adhesive resin layer of the copper foil with resin is formed to a test piece in which a comb-shaped electrode is provided on a single-sided flexible printed wiring board, and heating and pressing at 180 ° C. for 1 hour. A sample was prepared and evaluated by performing a test using a voltage of 10 V for 250 hours in an environment of 85 ° C./85% RH. And the migration degree after this test was evaluated visually. Those in which no migration occurred were defined as “pass”, and those other than this were defined as “fail”.

(Product storage stability)
Product storage stability was evaluated as follows. First, a copper foil with resin was produced and stored at 5 ° C. for 6 months. And the surface in which the adhesive resin layer of the copper foil with resin after the said preservation | save was formed is bonded to the test piece formed by providing the comb-shaped pattern in the flexible printed wiring board of the rolled copper foil of 35 micrometers thickness on one side, and 180 degreeC A sample was prepared by heating and pressing for 1 hour and evaluated by visually observing the appearance of the sample. The pattern filled with resin was regarded as “pass”, and the other pattern was defined as “fail”.

As seen in Table 1 above, each of the examples has good varnish preservability and copper foil peel strength, high flexibility, and satisfactory flexibility required for flexible printed wiring boards and the like. In addition, it was confirmed that the circuit filling property was excellent. In addition, since no halogen-based flame retardant is used, it is a material with little toxic gas and fuming.

Next, varnishes of the epoxy resin compositions for printed wiring boards of Examples 15 to 26 and Comparative Examples 3 to 5 were prepared according to the composition shown in Table 2 below.

(Examples 15 to 26 and Comparative Examples 3 to 5)
For Examples 15 to 26 and Comparative Examples 3 to 5, the components shown in Table 2 below were mixed in a container to prepare a varnish of an epoxy resin composition for a printed wiring board. The amount of each component used in Table 2 below is shown as a solid content ratio, the components (A), (B) and (C) are used in the mass ratio shown in Table 2 below, and the other components are (A). (B) (C) It used so that the mixture ratio with respect to the total amount of a component might become what is shown in following Table 2.

In addition, each component shown in the following Table 2 is as follows.

(A) Epoxy resin having a naphthalene skeleton (Structural Formula (1)): Epoxy resin having no naphthalene skeleton and containing a naphthalene skeleton (“NC-7000L” manufactured by Nippon Kayaku Co., Ltd., with the above structural formula (1)) Represented)
(A) Epoxy resin having naphthalene skeleton (Structural Formula (2)): Epoxy resin having no naphthalene skeleton and containing naphthalene skeleton (“EXA-9900” manufactured by DIC Corporation, represented by the above structural formula (2)) Stuff)
(A) Epoxy resin having naphthalene skeleton (structural formula (3)): Epoxy resin not containing halogen and having naphthalene skeleton (“HP-4700” manufactured by DIC Corporation, represented by the above structural formula (3)) Stuff)
(A) Biphenyl novolac epoxy resin: novolac type epoxy resin containing no phenol and having a phenol skeleton and a biphenyl skeleton (“NC-3000” manufactured by Nippon Kayaku Co., Ltd.)
(B) Phenol novolac type aminotriazine novolak resin (Structural Formula (4), R = H): Phenol novolac type aminotriazine novolak resin (“LA-7052” manufactured by DIC Corporation), represented by the above structural formula (4) And R is H), which was dissolved in methyl ethyl ketone, and the resin solid content was 60% by mass.

(B) Cresol novolac-type aminotriazine novolak resin (Structural Formula (4), R = CH ₃ ): Cresol novolac-type aminotriazine novolak resin (“LA-3018-50P” manufactured by DIC Corporation, the above structural formula (4) And R is CH ₃ ), dissolved in propylene glycol monomethyl ether, and the resin solid content was 50% by mass.

(B) Novolak type phenol resin: phenol novolak resin (manufactured by DIC Corporation, “TD-2090-60M”) dissolved in methyl ethyl ketone, and the resin solid content was 60% by mass.

(C) Carbodiimide-modified soluble polyamide: used was synthesized as described above. In addition, this was melt | dissolved in the mixed solvent (mass mixing ratio 4: 6) of isopropyl alcohol and toluene, and solid content concentration was 11 mass%.

-Aluminum alkylphosphinate (Structural formula (5), R ₁ = R ₂ = CH ₃ ): Aluminum alkylphosphinate (represented by the above structural formula (5), R ₁ and R ₂ are CH ₃ )
Aluminum alkylphosphinate (Structural formula (5), R ₁ = R ₂ = CH ₂ CH ₃ ): Aluminum alkylphosphinate (expressed by the above structural formula (5), R ₁ and R ₂ are CH ₂ CH ₃ some stuff)
Aluminum alkylphosphinate (Structural formula (5), R ₁ = R ₂ = CH ₂ CH ₂ CH ₃ ): Alkyl phosphinic acid aluminum (expressed by the above structural formula (5), wherein R ₁ and R ₂ are CH ₂ CH ₂ CH ₃ )
Phenoxy resin: A phenoxy resin (“YP-50” manufactured by Tohto Kasei Co., Ltd.) dissolved in methyl ethyl ketone, and the resin solid content was 65% by mass.

Curing accelerator: 2-ethyl-4-methylimidazole (“2E4MZ” manufactured by Shikoku Chemicals Co., Ltd.)
Phosphazene: Phosphazene (“SPB-100” manufactured by Otsuka Chemical Co., Ltd., represented by the above structural formula (6))
Next, using a comma coater and a dryer connected thereto, the varnish obtained as described above is applied to one side of a copper foil having a thickness of 12 μm and dried, and the thickness after drying is 50 μm. By forming a resin layer, a copper foil with resin (resin sheet with copper foil) was produced.

And about the said varnish, while evaluating varnish preservability, about the copper foil with a resin obtained as mentioned above, chemical resistance, copper foil peeling strength, solder heat resistance, flexibility, circuit filling property, difficulty Flammability, migration resistance, and glass transition temperature (Tg) were evaluated. The preparation conditions and evaluation conditions of the samples used for each of these evaluations are as described above, but the evaluation conditions for flame retardancy and glass transition temperature (Tg) are as follows. The evaluation results are shown in Table 2 below. Show.

(Flame retardance)
The flame retardancy was evaluated as “pass” if VTM-0 was satisfied and “failed” if it did not satisfy VTM-0 according to the flame retardancy criteria of 94 VTM according to UL94.

(Glass transition temperature (Tg))
The glass transition temperature (Tg) was determined from the loss tangent peak by the DMA method (tensile method).

As seen in Table 2 above, each of the examples has good varnish preservability and good copper foil peel strength, high flexibility, and satisfactory flexibility required for flexible printed wiring boards and the like. In addition, it was confirmed that the circuit filling property was excellent. In addition, since no halogen-based flame retardant is used, it is a material with little toxic gas and fuming.

Claims (19)

1. (A) Epoxy resin, (B) Epoxy resin curing agent, (C) A carbodiimide-modified soluble polyamide is contained as an essential component.
2. 2. The epoxy resin composition for printed wiring boards according to claim 1, wherein the content of the component (C) is 20 to 70% by mass with respect to the total amount of the components (A), (B) and (C). .
3. The epoxy resin composition for printed wiring boards according to claim 1 or 2, wherein an epoxy resin having a naphthalene skeleton is used as the component (A).
4. 4. The epoxy resin for printed wiring boards according to claim 3, wherein at least one of those represented by the following structural formulas (1) to (3) is used as the epoxy resin having a naphthalene skeleton. Composition.
   

   
5. 5. The component according to claim 1, wherein at least one of an aminotriazine novolak resin represented by the following structural formula (4) and dicyandiamide is used as the component (B). Epoxy resin composition for printed wiring boards.
   

   
6. The component (C) is obtained by adding 0.5 to 20 parts by mass of a carbodiimide compound and reacting with 100 parts by mass of the soluble polyamide. The epoxy resin composition for printed wiring boards according to any one of the above.
7. The epoxy resin composition for printed wiring boards according to any one of claims 1 to 6, wherein a phenoxy resin is contained.
8. The epoxy resin composition for printed wiring boards according to any one of claims 1 to 7, wherein at least one of a phosphorus-modified epoxy resin, a phosphorus-modified phenoxy resin, and a phosphorus-based flame retardant is contained. object.
9. The epoxy resin composition for printed wiring boards according to claim 8, wherein an aluminum alkylphosphinate represented by the following structural formula (5) is used as the phosphorus-based flame retardant.
   

   
10. The content of the aluminum alkylphosphinate represented by the structural formula (5) is 5 to 20% by mass with respect to the total amount of the components (A), (B) and (C). The epoxy resin composition for printed wiring boards as described.
11. A solder resist composition comprising the epoxy resin composition for a printed wiring board according to any one of claims 1 to 10.
12. A resin film, wherein the epoxy resin composition for a printed wiring board according to any one of claims 1 to 10 is formed into a film shape.
13. A resin sheet, wherein the epoxy resin composition for a printed wiring board according to any one of claims 1 to 10 is formed into a sheet shape.
14. A prepreg characterized in that the epoxy resin composition for printed wiring boards according to any one of claims 1 to 10 is impregnated into a base material and is in a semi-cured state.
15. A metal foil with a resin, wherein the epoxy resin composition for a printed wiring board according to any one of claims 1 to 10 is applied to the metal foil to be in a semi-cured state.
16. The epoxy resin composition for printed wiring boards according to any one of claims 1 to 10, is applied to a metal foil via an insulating layer composed of at least one of a coated material and a film-like material. A resin-coated metal foil characterized by being in a semi-cured state.
17. A coverlay, wherein the epoxy resin composition for a printed wiring board according to any one of claims 1 to 10 is applied to a plastic sheet and is in a semi-cured state.
18. A coverlay comprising the resin-coated metal foil according to claim 15 or 16.
19. A solder resist composition according to claim 11, a resin film according to claim 12, a resin sheet according to claim 13, a prepreg according to claim 14, a metal foil with resin according to claim 15, A flexible printed wiring board formed by using at least one of a metal foil with resin according to claim 16, a cover lay according to claim 17, and a cover lay according to claim 18.

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