JP2012188633A - Thermosetting resin composition, resin sheet with metal foil, and flexible printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosetting resin composition in which the change in color hardly occurs even when bent and which can form an insulating layer, wherein in the insulating layer, high flame retardance is exhibited and furthermore the bleed out of a flame retardant is prevented.SOLUTION: The thermosetting resin composition contains: a phosphorus-containing epoxy resin; a first phosphazene compound that has no reactivity with an epoxy group; a second phosphazene compound that has reactivity with an epoxy group; and a carbodiimide-modified soluble polyamide. The thermosetting resin composition does not contain an insoluble particulate filler.

Description

    The present invention relates to a thermosetting resin composition, a resin sheet with a metal foil formed using the thermosetting resin composition, and a flexible printed wiring board formed using the thermosetting resin composition.

  Many flexible printed wiring boards are used for small and thin electronic devices. In recent years, due to the demand for higher density and thinness in electronic devices, the need for multi-layered flexible printed wiring boards has increased, and the required quality and cost have become severe.

  In order to multilayer a flexible printed wiring board, a core material including an insulating layer (first insulating layer) made of polyimide film or the like and a conductor wiring (first conductor wiring) is further added to an insulating layer (second insulating layer). It is necessary to laminate the insulating layer) and the conductor wiring (second conductor wiring). As a method for forming the second insulating layer and the second conductor wiring, a method using a resin sheet with a metal foil can be mentioned.

  For example, Patent Document 1 contains an epoxy resin, an epoxy resin curing agent, and a carbodiimide-modified soluble polyamide as an epoxy resin composition for producing a metal foil with resin and a flexible printed wiring board, and further a phosphorus-modified epoxy resin, A resin composition containing at least one of a phosphorus-modified phenoxy resin and a phosphorus-based flame retardant is disclosed.

  However, the quality required for flexible printed wiring boards has become increasingly severe, and the appearance of flexible printed wiring boards has come to be regarded as important. In particular, the second insulating layer, which is often bent, may cause discoloration such as whitening due to the occurrence of fine cracks in the bent portion, and it is required that such discoloration does not occur. It has come to be.

  Furthermore, the insulating layer in the flexible printed wiring board is required to exhibit high flame retardancy and be difficult for the flame retardant to bleed out from the insulating layer.

  It is difficult to form an insulating layer that can achieve such various requirements at a high level, and therefore development of a resin composition for forming such an insulating layer is required.

International Publication No. WO2009 / 145224

  The present invention has been made in view of the above-mentioned reasons, and is thermosetting capable of forming an insulating layer that hardly causes discoloration even when bent, exhibits high flame retardancy, and further suppresses bleed out of the flame retardant. Resin sheet with metal foil comprising a resin layer formed from this thermosetting resin composition, and a flexible printed wiring board comprising an insulating layer formed from this thermosetting resin composition The purpose is to do.

  The thermosetting resin composition according to the present invention includes a phosphorus-containing epoxy resin, a first phosphazene compound that is not reactive with an epoxy group, a second phosphazene compound that is reactive with an epoxy group, and a carbodiimide-modified soluble Contains polyamide and no insoluble particulate filler.

  In the thermosetting resin composition according to the present invention, the second phosphazene compound preferably contains phenoxyphosphazene having 1 to 2 phenolic hydroxyl groups in one molecule.

  The thermosetting resin composition according to the present invention has a solid content ratio of 25 to 45% by mass of the phosphorus-containing epoxy resin, 2 to 12% by mass of the first phosphazene compound, and 5 of the second phosphazene compound. It is preferable to contain -15 mass% and the said carbodiimide modified | denatured soluble polyamide in the ratio of 30-60 mass%.

  The resin sheet with metal foil according to the present invention includes a metal foil and a first resin layer, and the first resin layer is formed from the thermosetting resin composition.

  The resin sheet with metal foil according to the present invention may further include a second resin layer different from the first resin layer, which is interposed between the metal foil and the first resin layer.

  The flexible printed wiring board which concerns on this invention is equipped with the insulating layer formed from the hardened | cured material of the said thermosetting resin composition.

  According to the present invention, it is possible to obtain a thermosetting resin composition capable of forming an insulating layer that hardly causes discoloration even when bent, exhibits high flame retardancy, and further suppresses bleed-out of the flame retardant.

  Furthermore, according to the present invention, a metal for forming an insulating layer that is unlikely to cause discoloration even when bent on a flexible printed wiring board, exhibits high flame retardancy, and further suppresses bleedout of flame retardant. A resin sheet with a foil is obtained.

  Furthermore, according to the present invention, it is possible to obtain a flexible printed wiring board including an insulating layer that hardly changes color even when bent, exhibits high flame retardancy, and further suppresses bleed out of the flame retardant.

(A) And (b) is sectional drawing which shows the resin sheet with metal foil which concerns on embodiment of this invention. It is sectional drawing which shows the flexible printed wiring board which concerns on embodiment of this invention. It is general | schematic sectional drawing which shows the manufacturing process of the flexible printed wiring board which concerns on embodiment of this invention. It is sectional drawing which shows the laminated body for flexible printed wiring board manufacture which concerns on embodiment of this invention.

  The thermosetting resin composition according to the present embodiment is used for forming an insulating layer of a printed wiring board, and particularly preferably used for forming an insulating layer of a flexible printed wiring board.

  The thermosetting resin composition according to the present embodiment includes a phosphorus-containing epoxy resin, a first phosphazene compound having no reactivity with an epoxy group, a second phosphazene compound having reactivity with an epoxy group, and a carbodiimide modification Contains soluble polyamide.

  Thus, since the thermosetting resin composition contains the phosphorus-containing epoxy resin, the first phosphazene compound, and the second phosphazene compound, the thermosetting resin composition is composed of a halogen-based flame retardant or an insoluble particulate filler. Even if it does not contain a flame retardant, the flame retardancy of the insulating layer is increased. Furthermore, among the compounds containing phosphorus in the thermosetting resin composition, the phosphorus-containing epoxy resin and the second phosphazene compound constitute a resin skeleton in the insulating layer, so that the insulating layer has high flame retardancy. The bleed-out of the phosphorus-containing compound from the insulating layer is suppressed.

  Furthermore, since the thermosetting resin composition contains the first phosphazene compound and the carbodiimide-modified soluble polyamide, the flexibility of the insulating layer formed from the thermosetting resin composition is increased, so that the insulating layer is bent. Cracks are less likely to occur.

  Furthermore, since the thermosetting resin composition does not contain an insoluble particulate filler, when the insulating layer is bent, peeling on the surface of the insoluble particulate filler and cracks starting from the insoluble particulate filler do not occur.

  For this reason, a printed wiring board provided with the thermosetting resin composition according to the present embodiment has excellent flame retardancy and suppresses bleed out of the flame retardant. Further, even if the insulating layer is bent, peeling or cracking is unlikely to occur in this insulating layer, and this insulating layer is difficult to discolor. Therefore, the thermosetting resin composition according to the present embodiment is suitably used for forming an insulating layer in a flexible printed wiring board that is frequently bent.

  Details of the composition of the thermosetting resin composition according to the present embodiment will be further described.

  The phosphorus-containing epoxy resin can be obtained, for example, by reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with 1,4-naphthoquinone and further reacting with a cresol novolac resin. In addition to this, a phosphorus-modified epoxy resin obtained by reacting a reaction product of an organic phosphorus compound and a quinone compound with an epoxy resin may be used.

  As the organophosphorus compound, an organophosphorus compound represented by the following formula (I) is preferable from the viewpoint that the glass transition temperature after moisture absorption can be increased, the solubility is good, and the phosphorus content is high.

  In the above formula (I), each R independently represents a hydrocarbon group having 1 to 6 carbon atoms, preferably a linear or branched alkyl group having 1 to 6 carbon atoms. n shows the integer of 0-4. Preferable specific examples of the organic phosphorus compound represented by the above formula (I) include 3,4,5,6-dibenzo-1,2-oxaphosphan-2-oxide.

  As the organophosphorus compound, diphenylphosphine oxide or the like can be used.

  Specific examples of the quinone compound to be reacted with the organic phosphorus compound include 1,4-benzoquinone, 1,2-benzoquinone, tolquinone, 1,4-naphthoquinone and the like. These may be used alone or in combination of two or more.

  As an epoxy resin used as a raw material for the phosphorus-modified epoxy resin, a novolac type epoxy resin such as a phenol novolak type epoxy resin or a cresol novolak type epoxy resin is preferably used from the viewpoint of ensuring the heat resistance of the cured product, particularly increasing the glass transition temperature. . The novolac type epoxy resin is preferably blended at a ratio of 20% by mass or more (upper limit is 100% by mass) of the total amount of the epoxy resin.

  When the epoxy resin used as the raw material of the phosphorus-modified epoxy resin is a mixture containing a novolac type epoxy resin, specific examples of the epoxy resin other than the novolac type epoxy resin include those having two or more epoxy groups in one molecule, For example, bisphenol type epoxy resin, resorcin type epoxy resin, polyglycol type epoxy resin, fluorene type epoxy resin and the like can be mentioned.

  The phosphorus-modified epoxy resin can be obtained, for example, by reacting the organic phosphorus compound and the quinone compound in a solvent such as toluene, and then mixing and reacting the reaction product with the epoxy resin.

  For example, when the organophosphorus compound of the above formula (I) is used, the reaction between the organophosphorus compound and the quinone compound is performed by blending the organophosphorus compound in an amount of 1 to 2 moles with respect to 1 mole of the quinone compound. It can be carried out by adding a quinone compound to a compound in which the compound is dissolved in an inert solvent such as dioxane, benzene, toluene, xylene and stirring with heating.

  As the quinone compound, those previously powdered or dissolved in a solvent can be used. Since the reaction between the organophosphorus compound and the quinone compound is accompanied by heat generation, it is desirable to add a predetermined amount of the quinone compound by a dropping method so that rapid heat generation does not occur. After the addition of the quinone compound, the reaction is allowed to proceed for 1 to 4 hours at 50 to 150 ° C., for example.

  Thereafter, when a reaction product of an organophosphorus compound and a quinone compound is reacted with an epoxy resin to synthesize a phosphorus-modified epoxy resin, for example, an epoxy resin is added to the reaction product, and if necessary A catalyst such as triphenylphosphine is added, the reaction temperature is set to 100 to 200 ° C., and the reaction proceeds while stirring.

  The phosphorus-modified epoxy resin thus obtained has a phosphorus content of 1.2 to 4 mass by appropriately changing the synthesis conditions from the viewpoint of suppressing the decrease in heat resistance while ensuring flame retardancy. % And the epoxy equivalent is preferably adjusted to 200 to 600 g / eq.

  The content ratio of the phosphorus-containing epoxy resin in the thermosetting resin composition is appropriately set so that the insulating layer formed from the thermosetting resin composition exhibits high flame retardancy and excellent flexibility. In particular, the content of the phosphorus-containing epoxy resin in the thermosetting resin composition is preferably 25% by mass or more in terms of solid content, more preferably 30% by mass or more, and this content is 45% by mass. % Or less, more preferably 40% by mass or less. The solid content ratio is a ratio based on the solid content in the thermosetting resin composition (a component that becomes a cured product, that is, a component excluding a component that volatilizes during curing).

  The first phosphazene compound having no reactivity with an epoxy group does not have a functional group such as a phenolic hydroxyl group having reactivity with an epoxy group. Examples of the first phosphazene compound include compounds represented by the following [Chemical Formula 2].

  In [Chemical Formula 2], n is preferably an integer of 3 to 25.

  The content ratio of the first phosphazene compound in the thermosetting resin composition is such that the insulating layer formed from the thermosetting resin composition exhibits high flame retardancy and excellent flexibility, and from this insulating layer The first phosphazene compound is appropriately set so that bleeding out of the first phosphazene compound is sufficiently suppressed. In particular, the content ratio of the first phosphazene compound in the thermosetting resin composition is preferably 2% by mass or more, more preferably 4% by mass or more in terms of solid content. The content is preferably 12% by mass or less, and more preferably 10% by mass or less.

  The second phosphazene compound having reactivity with an epoxy group has a functional group such as a phenolic hydroxyl group having reactivity with the epoxy group.

  Examples of the phosphazene compound having a phenolic hydroxyl group include phenoxyphosphazene having a phenolic hydroxyl group. Examples of phenoxyphosphazene include compounds represented by the following [Chemical Formula 3].

  N in [Chemical Formula 3] is preferably an integer of 3 to 25.

  In [Chemical Formula 3], the structures of a plurality of R in one molecule are independently determined. At least one of a plurality of R in one molecule preferably has a structure selected from the group shown in the following [Chemical Formula 4].

R ⁴ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁵ is an alkyl group having 1 to 4 carbon atoms.

  In particular, phenoxyphosphazene has the structure shown in the above [Chemical Formula 3], wherein a plurality of Rs in one molecule are each independently a phenyl group or a hydroxyphenyl group, and at least one R in one molecule is a hydroxyl group. A compound that is a phenyl group is preferred.

  Further, as phenoxyphosphazene, phenoxyphosphazene having 1 to 2 phenolic hydroxyl groups in one molecule is particularly preferably used. As a particularly preferred example of the phenoxyphosphazene having 1 to 2 phenolic hydroxyl groups in one molecule, it has the structure shown in [Chemical Formula 3], wherein n is an integer of 3 to 25, A plurality of R1s are each independently a phenyl group or a hydroxyphenyl group, and a compound having a structure in which the number of hydroxylphenyl groups in one molecule is 1 or 2 can be mentioned.

  When phenoxyphosphazene having 1 to 2 phenolic hydroxyl groups in one molecule is used, the fluidity at the time of heating of the thermosetting resin composition is improved and the insulating layer formed from the thermosetting resin composition Flexibility is particularly improved. The phenoxyphosphazene having 1 to 2 phenolic hydroxyl groups in one molecule has the structure shown in [Chemical Formula 3], n = 3, and one hydroxyphenyl group in one molecule. A mixture of the molecule and two molecules is preferred. The average number of phenolic hydroxyl groups per molecule in this mixture is preferably 1.3 to 1.8.

  The ratio of phenoxyphosphazene having 1 to 2 phenolic hydroxyl groups in one molecule to the entire second phosphazene compound is preferably 1% by mass or more, and more preferably 35% by mass or more. Further, this ratio is preferably 100% by mass or less, and more preferably 75% by mass or less. It is also preferable that the second phosphazene compound is only phenoxyphosphazene having 1 to 2 phenolic hydroxyl groups in one molecule.

  The content ratio of the second phosphazene compound in the thermosetting resin composition is appropriately set so that the insulating layer formed from the thermosetting resin composition exhibits high flame retardancy and excellent flexibility. In particular, the content ratio of the second phosphazene compound in the thermosetting resin composition is preferably 5% by mass or more in terms of solid content. Further, the content is preferably 15% by mass or less, and more preferably 10% by mass or less.

  A carbodiimide-modified soluble polyamide is a reaction product of a soluble polyamide and a carbodiimide compound. A reactive functional group such as a carboxyl group or an amino group possessed by the soluble polyamide reacts with a carbodiimide group or an isocyanate group of a carbodiimide compound capable of reacting with these to produce a carbodiimide-modified soluble polyamide.

  The soluble polyamide is a polyamide having solubility in an organic solvent. The soluble polyamide is 1 part by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass with respect to 100 parts by mass of a mixture of alcohol and at least one of an aromatic organic solvent and a ketone organic solvent. It is preferable that at least part of the polyamide is completely soluble. The alcohol is at least one selected from, for example, methanol, ethanol, and isopropyl alcohol. The aromatic organic solvent is at least one selected from, for example, benzene and toluene. The ketone-based organic solvent is at least one selected from, for example, cyclohexanone, 2-butanone, and cyclopentanone. The boiling points of these alcohols, aromatic solvents and ketone solvents are preferably 130 ° C. or lower.

  The soluble polyamide is obtained, for example, by subjecting a polyamide other than the soluble polyamide (polyamide before solubilization) to a treatment for solubilization. Examples of the treatment method for solubilization include a method in which a hydrogen atom in an amide group of a polyamide before solubilization is partially substituted with a methoxymethyl group. When a methoxy group is introduced into the polyamide by this method, the crystallinity of the polyamide is inhibited by losing the hydrogen bonding ability from the amide group, thereby increasing the solubility of the polyamide in the solvent. Examples of the treatment method for solubilization include a method in which polyether or polyester is introduced into a polyamide molecule before solubilization to form a copolymer. Examples of the polyamide before solubilization include nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, nylon 46, and the like.

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

  A carbodiimide compound is a compound having one or more carbodiimide groups in one molecule. Examples of the carbodiimide compound include a monocarbodiimide compound and a polycarbodiimide compound. A carbodiimide compound is synthesized, for example, by a decarboxylation condensation reaction of various polyisocyanates in a solvent-free or inert solvent at a temperature of about 70 ° C. or higher in the presence of an organic phosphorus compound or organometallic compound as a catalyst. The

  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 easy availability industrially.

  The polycarbodiimide compound is produced by various methods. For example, a polycarbodiimide compound may be prepared by a known 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).

  The carbodiimide compound is not particularly limited as long as it has one or more carbodiimide groups in one molecule. From the viewpoint of improving the reactivity and hydrolysis stability, 4,4′-dicyclohexylmethanecarbodiimide, etc. A polycarbodiimide compound having two or more carbodiimide groups in the molecule is preferable. In particular, aliphatic or alicyclic polycarbodiimide compounds are preferred. The degree of polymerization of the polycarbodiimide compound is preferably in the range of 2-30, more preferably in the range of 2-20. When the polymerization degree is 2 or more, the heat resistance of the printed wiring board is preferable, and when the polymerization degree is 20 or less, the compatibility between components in the thermosetting resin composition is preferable. .

  Organic diisocyanate is mentioned as polyisocyanate used for manufacture of a polycarbodiimide compound. Examples of organic diisocyanates 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 diene Isocyanate, 2,6-tolylene diisocyanate, mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate, 2,6-diisopropylphenyl diisocyanate 1,3,5-triisopropylbenzene 2,4-diisocyanate, and the like. Among these, from the viewpoint of improving the flexibility and moisture resistance of the flexible printed wiring board 1, aliphatic (including alicyclic) organic diisocyanates are preferable, and in particular, ilophorone diisocyanate and dicyclohexylmethane-4,4 ′. -Diisocyanate, tetramethylxylylene diisocyanate and mixtures thereof are more preferred.

  During the production of the polycarbodiimide compound, the degree of polymerization of the polycarbodiimide compound can be appropriately controlled by stopping the polymerization reaction halfway by cooling the reaction system during the polymerization reaction of the polyisocyanate. In this case, the terminal of the molecule of the polycarbodiimide compound is an isocyanate group. In order to more appropriately control the degree of polymerization of the polycarbodiimide compound, a compound such as a monoisocyanate compound capable of reacting with an isocyanate group (hereinafter referred to as an end-capping agent) is an isocyanate group at the end of the molecule of the polycarbodiimide compound. By reacting with all or a part of the polycarbodiimide compound, all or part of the isocyanate groups of the polycarbodiimide compound may be sealed. When the degree of polymerization of the polycarbodiimide compound is appropriately controlled, the compatibility between the soluble polyamide and the polycarbodiimide compound is improved, and the storage stability of the member including the first resin layer 7 is improved.

  Examples of the monoisocyanate compound that can be used as the end-capping agent include phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, and naphthyl isocyanate.

End capping agents other than monoisocyanate compounds may be used. Examples of the end-capping agent other than the monoisocyanate compound include active hydrogen compounds that can react with an isocyanate group. As such an active hydrogen compound, for example, (i) an aliphatic, aromatic or alicyclic compound having an —OH group, methanol, ethanol, phenol, cyclohexanol, N-methylethanolamine, polyethylene glycol monomethyl ether, compounds such as polypropylene glycol monomethyl ether; (ii) = diethylamine having an NH group, compounds such as dicyclohexylamine; butylamine with (iii) -NH ₂ group, cyclohexylamine; a (iv) -COOH groups (V) compounds having an epoxy group; (vi) compounds having an epoxy group; (vii) acetic anhydride, methyltetrahydro; compounds having a succinic acid, benzoic acid, cyclohexane and the like; Phthalic anhydride, methyl Kisahidoro anhydride such as phthalic anhydride, and the like.

The decarboxylation condensation reaction of organic diisocyanate can proceed in the presence of a suitable carbodiimidization catalyst. As the carbodiimidization catalyst, an organophosphorus compound, an organometallic compound (represented by the general formula M- (OR) _n , where 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), and other metal elements, R is carbon number 1-20 And an alkyl group or an aryl group, and n represents the valence of M).

  Among these carbodiimidization catalysts, particularly from the viewpoint of improving reaction activity, phospholene oxides are used from among organic phosphorus compounds, and alkoxides of titanium, hafnium, or zirconium from among organometallic compounds. Are preferably used. Specific examples of the phosphorene oxides include 3-methyl-1-phenyl-2-phospholene-1-oxide, 3-methyl-1-ethyl-2-phospholene-1-oxide, and 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 their double bond isomers Is mentioned. Of these phospholene oxides, 3-methyl-1-phenyl-2-phospholene-1-oxide is preferably used in terms of industrial availability.

  A carbodiimide-modified soluble polyamide is produced by reacting a soluble polyamide and a carbodiimide compound, for example, in the presence or absence of a solvent.

  As a method of reacting soluble polyamide and carbodiimide compound in the presence of a solvent, for example, there is a method of adding the soluble polyamide and carbodiimide compound to the solvent and agitating the resulting solution while heating to advance the reaction. Can be mentioned. In particular, it is preferable that the soluble polyamide is first added to a solvent, and a carbodiimide compound is further added to the resulting solution, and then this solution is heated and stirred under reflux (reflux) to advance the reaction. When the solvent is removed from the solution after the reaction under normal pressure or reduced pressure, a carbodiimide-modified soluble polyamide is obtained.

  Examples of a method of reacting a soluble polyamide and a carbodiimide compound in the absence of a solvent include, for example, a method in which the reaction is allowed to proceed by mixing a carbodiimide compound with a soluble polyamide heated to a temperature equal to or higher than the melting point, or a soluble polyamide. And a carbodiimide compound are melt-kneaded by a twin screw extruder and the reaction is allowed to proceed while mixing.

  When the soluble polyamide reacts with the carbodiimide compound, the ratio of the carbodiimide compound to 100 parts by mass of the soluble polyamide is preferably in the range of 0.5 to 20 parts by mass, and more preferably 1 to 10 parts by mass. In this case, the moisture resistance and heat resistance of the flexible printed wiring board are sufficiently improved, and the plasticity of the flexible printed wiring board is not increased excessively and the impact resistance is not easily lost. That is, when the ratio of the carbodiimide compound is 0.5 parts by mass or more, the moisture resistance and heat resistance of the flexible printed wiring board are sufficiently improved. On the other hand, when the ratio is 20 parts by mass or less, the plasticity of the flexible printed wiring board becomes too high and the impact resistance is hardly deteriorated.

  During the reaction between the soluble polyamide and the carbodiimide compound, it is preferable that the reaction system does not contain a compound that inhibits the modification of the soluble polyamide. In particular, the reaction system contains only the carbodiimide compound, the soluble polyamide and the solvent used as necessary. It is preferable. Specific examples of the compound that inhibits the modification of the soluble polyamide include epoxy resins, amine resins, melamine resins, and phenol resins.

  The reaction time of the soluble polyamide with the carbodiimide compound is appropriately set according to the type of the soluble polyamide or carbodiimide compound, the reaction method, the reaction temperature, etc., but is preferably in the range of 1 to 500 minutes, preferably 5 to 200 minutes. If it is the range, it is still more preferable.

  The temperature of the reaction system during the reaction between the soluble polyamide and the carbodiimide compound is also appropriately set according to the type of the soluble polyamide or carbodiimide compound, the reaction method, the reaction temperature, etc., but is preferably in the range of 50 to 250 ° C. . In particular, when the soluble polyamide and the carbodiimide compound react in the presence of a solvent, the temperature of the reaction system is preferably in the range of 50 to 150 ° C, more preferably in the range of 70 to 130 ° C. On the other hand, when the soluble polyamide and the carbodiimide compound react in the absence of a solvent, the temperature of the reaction system is preferably in the range of 130 to 250 ° C, more preferably 150 to 220 ° C. When the temperature of this reaction system is 50 ° C. or higher, the reaction between the soluble polyamide and the carbodiimide compound is sufficiently fast and the modification of the soluble polyamide occurs rapidly, which is preferable from an industrial viewpoint. Furthermore, it is preferable that the temperature of the reaction system is 250 ° C. or less because the product is hardly deteriorated due to decomposition of the resin or the like.

  Thus, when soluble polyamide and a carbodiimide compound react, soluble polyamide will modify and it will become carbodiimide modified soluble polyamide. As this reaction proceeds, the carbodiimide group of the carbodiimide compound decreases accordingly. For this reason, when each of the raw material and the product is measured by infrared spectroscopy, the peak attributed to the carbodiimide group decreases in the infrared absorption spectrum measured for the product. Furthermore, when differential thermogravimetric analysis of the raw material and the product is performed, a plurality of absorption peaks such as an absorption peak due to the amide resin and an absorption peak due to the carbodiimide resin are observed in the raw material, but in the product, the endothermic peak is It is aggregated into one. These confirm that the soluble polyamide has been modified.

  A composition containing a carbodiimide-modified soluble polyamide is excellent in storage stability as compared with a composition containing a soluble polyamide and a carbodiimide compound. That is, a composition containing a soluble polyamide and a carbodiimide compound thickens when it is made into a solution, and becomes easier to gel, whereas a composition containing a carbodiimide-modified soluble polyamide is less susceptible to changes such as thickening, Long-term storage is possible.

  The content ratio of the carbodiimide-modified soluble polyamide in the thermosetting resin composition is appropriately set, but is preferably in the range of 30 to 60% by mass in terms of solid content. If the content of the carbodiimide-modified soluble polyamide is 30% by mass or more, the flexibility of the flexible printed wiring board is improved. This content is preferably 35% by mass or more. Moreover, the flame retardance and heat resistance of a flexible printed wiring board improve that this content is 60 mass% or less. This content is preferably 45% by mass or less.

  The thermosetting resin composition does not contain insoluble particulate filler as described above. The insoluble particulate filler refers to inorganic particles and organic particles that are incompatible with the components in the thermosetting resin composition. That is, it refers to particles that remain in the insulating layer without being dissolved in the thermosetting resin composition. In general, inorganic particles such as aluminum hydroxide and magnesium hydroxide, and organic particles such as organic phosphate may be used as a flame retardant. In this embodiment, such particles are contained in the thermosetting resin composition. Not. For this reason, even if the insulating layer formed from the thermosetting resin composition is bent, cracks originating from the insoluble granular filler do not occur in the insulating layer. Furthermore, in this embodiment, even if it does not contain an insoluble granular filler, the insulating layer formed from a thermosetting resin composition exhibits excellent flame retardancy.

  The thermosetting resin composition may further contain an epoxy resin other than the phosphorus-containing epoxy resin. As this epoxy resin, a glycidyl ether type epoxy resin, a glycidyl ester type epoxy resin, a glycidyl amine type epoxy resin, an oxidation type epoxy resin and the like can be included. 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 may include hydrophthalic acid type epoxy resins, dimer acid type epoxy resins, and the like. Examples of the glycidylamine type epoxy resin include aromatic amine type epoxy resins and aminophenol type epoxy resins. An alicyclic epoxy resin is mentioned as an oxidation type epoxy resin. Examples thereof include an epoxy resin having a naphthalene skeleton and a novolac type epoxy resin having a phenol skeleton and a biphenyl skeleton (biphenyl novolac epoxy resin).

  When an epoxy resin other than the phosphorus-containing epoxy resin is used, it is particularly preferable to use an epoxy resin having a naphthalene skeleton. In this case, the heat resistance, migration resistance, and chemical resistance of the flexible printed wiring board are improved. As the epoxy resin having a naphthalene skeleton, at least one of the compounds represented by the following structural formulas (1) to (3) is preferably used. In this case, the heat resistance, migration resistance, Chemical resistance is further improved.

  It is preferable that all the epoxy resins including the phosphorus-containing epoxy resin and the other epoxy resins in the thermosetting resin composition do not contain a halogen.

  It is also preferred that the thermosetting resin composition further contains a curing agent. Curing agents can include polyamines, modified polyamines, acid anhydrides, hydrazine derivatives, polyphenols, and the like. Examples of polyamines include aliphatic polyamines, alicyclic polyamines, and aromatic polyamines. Among these, examples of the aliphatic polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, and diethylaminopropylamine. Examples of the alicyclic polyamine include isophorone diamine, 1,3-bisaminomethylcyclohexane, bis (4-aminocyclohexyl) methane, norbornene diamine, 1,2-diaminocyclohexane, and laromine. Examples of the aromatic polyamine include diaminodiphenylmethane, metaphenylenediamine, and diaminodiphenylsulfone. Examples of acid anhydrides include hexahydrophthalic anhydride, methyl tetrahydro anhydride, methyl hexahydrophthalic anhydride, methyl nadic anhydride, hydrogenated methyl nadic anhydride, trialkyltetrahydrophthalic anhydride, and methylcyclohexene tetracarboxylic acid. Anhydride, trimellitic anhydride, pyromellitic acid-free, benzophenone tetracarboxylic dianhydride, aliphatic dibasic acid polyanhydride and the like can be mentioned. 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. The curing agent may include an aminotriazine novolac resin, a novolac type phenol resin, and the like.

  In particular, the curing agent preferably contains at least one of an aminotriazine novolak resin represented by the following structural formula (4) and dicyandiamide. In this case, the B-stage resin layer formed from the thermosetting resin composition is stably maintained in the B-stage for a long period of time (improving storage stability) and flexible printing. The flame retardancy and chemical resistance of the wiring board are improved.

  Although content of the hardening | curing agent in a thermosetting resin composition is set suitably, especially 10-45 mass with respect to the total amount of the epoxy resin in a thermosetting resin composition, a hardening | curing agent, and a carbodiimide modified soluble polyamide. % Is preferable.

  The thermosetting resin composition may contain a curing accelerator such as 2-ethyl-4-methylimidazole as necessary.

  It is also preferred that the thermosetting resin composition further contains a phenoxy resin. In this case, the flexibility of the flexible printed wiring board is further improved. The phenoxy resin may include bisphenol A type phenoxy resin, bisphenol A / bisphenol F type copolymer type phenoxy resin, and the like. The content of the phenoxy resin in the thermosetting resin composition is preferably in the range of 5 to 30% by mass in terms of solid content.

  The thermosetting resin composition preferably contains no phosphorus compound other than the above-mentioned containing epoxy resin, first phosphazene compound, and reactive phosphazene compound from the viewpoint of heat resistance and insulation reliability.

  The thermosetting resin composition may further contain a dye. Even if the insulating layer formed from the thermosetting resin composition has sufficiently high flexibility, slight cracking may occur in the insulating layer when the insulating layer is severely bent. Even with such a slight crack, the insulating layer may be partially whitened to deteriorate the appearance of the insulating layer. However, when the thermosetting resin composition contains a dye, whitening of the insulating layer becomes inconspicuous and the appearance of the insulating layer is further improved. Furthermore, when an inorganic pigment is used, there is a risk that cracks originating from the particles of the inorganic pigment may occur in the insulating layer, but there is an advantage that the dye does not cause such cracks.

  Although it does not restrict | limit especially as dye, C.I. Solvent Black 7, C.I. Solvent Black 3, C.I. Solvent Red, C.I. Solvent YelloW 14 etc. may be used. Although the content rate of the dye in a thermosetting resin composition is set suitably, it is preferable that it is the range of 0.01-1 mass% in solid content ratio, for example.

  The thermosetting resin composition is prepared by blending the above components. Furthermore, the thermosetting resin composition may contain an organic solvent for viscosity adjustment, if necessary.

  The insulating layer can be formed by thermosetting the thermosetting resin composition according to the present embodiment. Since this insulating layer has high flexibility as described above, even if it is bent, cracks are not easily generated, the flame retardancy is high, and further, the flame retardant bleed-out hardly occurs.

  In particular, the tensile elastic modulus of the cured product of the thermosetting resin composition is 1.5 GPa or less, that is, the tensile elastic modulus of the insulating layer formed from the thermosetting resin composition is 1.5 GPa or less. preferable. In this case, the flexibility of the insulating layer is particularly high, so that the generation of cracks when the insulating layer is bent is further suppressed. The lower limit of the tensile elastic modulus is not particularly limited, but is practically preferably 0.1 GPa or more. This tensile modulus is measured with a viscoelastic spectrometer at a temperature of 30 ° C. In order to suppress the occurrence of cracks, it is more preferable that the tensile elastic modulus is 1.2 GPa or less.

  The resin sheet 9 with metal foil which concerns on this embodiment is provided with the metal foil 10 and the 1st resin layer 7 in a semi-hardened state (B stage state), as FIG.1 (a) shows. The first resin layer 7 is formed from the thermosetting resin composition according to this embodiment. This resin sheet 9 with a metal foil is preferably used for multilayering of a printed wiring board, and particularly preferably for multilayering of a flexible printed wiring board.

  The resin sheet 9 with metal foil can be produced by applying a thermosetting resin composition on a metal foil 10 such as a copper foil, and further heating and drying the thermosetting resin composition to be semi-cured. In this case, the first resin layer 7 made of a semi-cured product of the thermosetting resin composition is formed on the metal foil 10, thereby the metal foil 10 and the first layer directly laminated on the metal foil 10. A resin sheet 9 with a metal foil comprising the resin layer 7 is obtained. In this case, the heating conditions at the time of heating and drying of the thermosetting resin composition are appropriately set, but the heating temperature is preferably in the range of 130 ° C. to 160 ° C., and the heating time is preferably in the range of 2 to 10 minutes.

  It is also preferable that the resin sheet with metal foil 9 includes a second resin layer 8 interposed between the metal foil 10 and the first resin layer 7 as shown in FIG. In this case, the presence of the second resin layer 8 improves the insulating reliability of the flexible printed wiring board formed from the resin sheet 9 with metal foil. That is, when creating a flexible print using the resin sheet 9 with metal foil, even if the first resin layer 7 flows, the thickness of the insulating layer is ensured by the presence of the second resin layer 8. This improves the insulation reliability. The 2nd resin layer 8 is formed from the hardened | cured material or semi-hardened | cured material of resin which has a composition different from the thermosetting resin composition which concerns on this embodiment, or a resin composition.

  The second resin layer 8 is formed of at least one selected from, for example, a coated material and a sheet-like material. The coated product is a liquid resin or resin composition that forms the second resin layer 8 by being coated on the metal foil 10. A sheet-like material is a resin or a resin composition molded into a sheet shape.

  The second resin layer 8 is formed, for example, by applying a liquid resin such as a liquid polyimide resin on the metal foil 10 and curing or semi-curing the liquid resin. In this case, the second resin layer 8 made of a cured or semi-cured liquid resin is formed. The second resin layer 8 may be formed by applying a liquid resin such as a liquid polyimide resin on the metal foil 10 and further overlapping a resin film such as a polyimide film on the liquid resin. In this case, the 2nd resin layer 8 which consists of hardened | cured material or semi-hardened | cured material of a liquid resin, and a resin film is formed. After the second resin layer 8 is formed on the metal foil 10, the thermosetting resin composition according to the present embodiment is applied on the second resin layer 8, and the thermosetting resin composition is further applied. By heating and drying and semi-curing, the first resin layer 7 made of a semi-cured product of the thermosetting resin composition is formed. Thereby, the resin sheet 9 with metal foil provided with metal foil, the 1st resin layer 7, and the 2nd resin layer 8 is obtained.

  The flexible printed wiring board which concerns on this embodiment is provided with the insulating layer formed from the hardened | cured material of the thermosetting resin composition which concerns on this embodiment.

  As shown in FIG. 2, in the present embodiment, the flexible printed wiring board 1 includes a bendable first insulating layer 2 and a first conductor wiring laminated on the first insulating layer 2. 3 and a second insulating layer 4 laminated on the first insulating layer 2 and covering the first conductor wiring 3. This 2nd insulating layer 4 is formed from the hardened | cured material of the thermosetting resin composition which concerns on this embodiment. Furthermore, in this embodiment, the flexible printed wiring board includes a second conductor wiring 5 laminated on the second insulating layer 4.

  In the present embodiment, the first conductor wiring 3 is laminated on the first surface in the thickness direction of the first insulating layer 2, and the first conductor layer 3 is stacked on the second surface in the thickness direction of the first insulating layer 2. Conductor wiring 3 is laminated. Further, a second insulating layer 4 is laminated on the first surface of the first insulating layer 2 so as to cover the first conductor wiring 3, and on the second surface of the first insulating layer 2. A second insulating layer 4 is laminated so as to cover the first conductor wiring 3. Further, a second conductor wiring 5 is laminated on each second insulating layer 4.

  The first insulating layer 2 has flexibility. The first insulating layer 2 is formed of various highly flexible insulating materials such as polyimide resin, liquid crystal polymer, polyethylene terephthalate resin, and polyethylene naphthalate resin. Although the thickness of the 1st insulating layer 2 is set suitably, it is preferable that it is 5 micrometers or more. The thickness is preferably 50 μm or less, and more preferably 25 μm or less.

  The first conductor wiring 3 can be formed of a metal such as copper. Although the thickness of the 1st conductor wiring 3 is set suitably, it is preferable that it is the range of 9-70 micrometers, it is still more preferable if it is the range of 9-35 micrometers, and it is especially preferable if it is the range of 9-12 micrometers.

  The 1st insulating layer 2 and the 1st conductor wiring 3 in the flexible printed wiring board 1 are formed from a flexible laminated board, for example. The flexible laminate includes a first insulating layer and a metal foil laminated on the first insulating layer. The first insulating layer 2 in the flexible printed wiring board 1 and the first insulating layer in the flexible laminate are the same. The flexible laminate is formed, for example, by bonding or heat-sealing a metal foil such as a copper foil to a member made of only the first insulating layer. In the present embodiment, the metal foil is laminated on the first surface in the thickness direction of the first insulating layer, and the metal foil is further laminated on the second surface in the thickness direction of the first insulating layer.

  The first conductor wiring 3 is formed by performing a process such as an etching process on each metal foil of the flexible laminate. Furthermore, an opening is formed in the first insulating layer 2 and through-hole 6 may be formed by hole plating in the opening. Thereby, the core material 11 (refer FIG. 3) provided with the 1st insulating layer 2 and the 1st conductor wiring 3 is obtained. In the core material 11 in the present embodiment, the first conductor wiring 3 is formed on the first surface in the thickness direction of the first insulating layer 2, and further on the second surface in the thickness direction of the first insulating layer 2. A first conductor wiring 3 is formed.

  The 2nd insulating layer 4 and the 2nd conductor wiring 5 in a flexible printed wiring board are formed from the resin sheet 9 with a metal foil in this embodiment. When the flexible printed wiring board 1 is produced from the core material 11 and the resin sheet 9 with metal foil, for example, as shown in FIG. 3, the resin sheet 9 with metal foil is formed on the core material 11 by the first resin layer 7. The first conductor wiring 3 is overlaid so as to be covered. In the present embodiment, the resin sheet 9 with metal foil is stacked on the first surface in the thickness direction of the core material 11, and the resin sheet 9 with metal foil is stacked on the second surface in the thickness direction of the core material 11. . In this state, the resin sheet 9 with metal foil and the core material 11 are pressed and heated in the direction in which they are laminated by the hot platen 12. At this time, a hard plate for molding, a soft or elastic member (cushion material, for example, a TPX film manufactured by Mitsui Chemicals, Inc. (trade name) between the resin sheet with metal foil 9 and the hot platen 12 as necessary. The first resin layer 7 of each resin sheet 9 with a metal foil is first softened and filled between the lines of the first conductor wiring 3, and the member 13 such as Opulan) may be interposed. When the through hole 6 is formed in one insulating layer 2, the through hole 6 is also filled in. Subsequently, each first resin layer 7 is thermally cured, whereby each first resin layer is cured. 7 becomes the second insulating layer 4. When the resin sheet 9 with the metal foil includes the first resin layer 7 and the second resin layer 8, the cured product of the first resin layer 7. And the second resin layer 8 or a cured product thereof, and the second insulating layer 4 and That.

  In particular, when the thermosetting resin composition contains phenoxyphosphazene having 1 to 2 phenolic hydroxyl groups in one molecule, the first resin layer 7 is formed of the thermosetting resin according to this embodiment. When the first resin layer 7 is heated and softened, the fluidity of the first resin layer 7 becomes very high. For this reason, when the first resin layer 7 softened in the above process is filled between the lines of the first conductor wiring 3, the filling property of the first resin layer 7 between the lines, that is, between the lines. The filling property of the second insulating layer 4 becomes very high.

  When the core material 11 and the resin sheet 9 with metal foil are laminated and integrated by the above method, the first conductor wiring 3, the second insulating layer 4, the metal on the first insulating layer 2 as shown in FIG. A laminate 14 for manufacturing a flexible printed wiring board having a structure in which the foils 10 are sequentially laminated is obtained. In the laminate 14 for manufacturing a flexible printed wiring board in the present embodiment, the first conductor wiring 3, the second insulating layer 4, and the metal foil 10 are sequentially formed on the first surface in the thickness direction of the first insulating layer 2. The first conductive wiring 3, the second insulating layer 4, and the metal foil 10 are sequentially stacked on the second surface in the thickness direction of the first insulating layer 2.

  The second conductor wiring 5 is formed by subjecting each outermost metal foil 10 in the laminate 14 for manufacturing a flexible printed wiring board to a known process for forming a wiring such as an etching process. As a method for forming the second conductor wiring 5, for example, an etching resist corresponding to the pattern of the second conductor wiring 5 is formed on the metal foil 10, and then the etching resist in the metal foil 10 is covered by an etching process. There is a method of removing a portion that is not, and then removing the etching resist.

  In the present embodiment, the thickness of the second insulating layer 4 is not particularly limited, but is preferably in the range of 5 to 50 μm. In this case, the second insulating layer 4 exhibits a sufficiently high insulating performance, the second insulating layer 4 is sufficiently bent easily, and further cracks are generated when the second insulating layer 4 is bent. Occurrence is sufficiently suppressed. The thickness of the second insulating layer 4 is preferably in the range of 5 to 40 μm, and more preferably in the range of 5 to 30 μm. In the present embodiment, the thickness of the second conductor wiring 5 is not particularly limited, but is preferably in the range of 9 to 70 μm, more preferably 9 to 35 μm, and particularly preferably 9 to 12 μm.

  In the present embodiment, the flexible printed wiring board 1 may be further multilayered by stacking another insulating layer and conductor wiring on the second insulating layer 4 and the second conductor layer 5. . In further multilayering of the flexible printed wiring board 1, it is preferable to use the resin sheet 9 with a metal foil according to the present embodiment.

  In this aspect, the flexible printed wiring board 1 includes the second conductor wiring 5, but the flexible printed wiring board 1 does not include the second conductor wiring 5 as long as the second insulating layer 4 is included. May be.

  Furthermore, in this embodiment, the 2nd insulating layer 4 is formed from the 1st resin layer 7 in the resin sheet 9 with a metal foil, However, The formation method of the 2nd insulating layer 4 is not restricted to this. For example, by a method in which a semi-cured resin sheet formed from the thermosetting resin composition according to the present embodiment is superposed on the first insulating layer 2 and the first conductor wiring 3 and heated and pressurized, A second insulating layer 4 made of a cured product may be formed.

[Synthesis of carbodiimide compounds]
A mixture was obtained by mixing 590 g of 4,4′-dicyclohexylmethane diisocyanate, 62.6 g of cyclohexylisocyanate, and 6.12 g of carbodiimidization catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide). . The mixture was reacted by heating at 180 ° C. for 48 hours. As a result, 4,4′-dicyclohexylmethane carbodiimide resin (polymerization degree = 10), which is a carbodiimide compound, was obtained.

[Synthesis of carbodiimide-modified soluble polyamide]
To 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) were added and stirred. To dissolve. 5.0 g of the above carbodiimide compound (4,4′-dicyclohexylmethanecarbodiimide resin) is added to the solution thus obtained, the flask is immersed in an oil bath at 120 ° C., heated and stirred for 3 hours under reflux, and then dried under reduced pressure. Then, the carbodiimide-modified soluble polyamide was obtained by removing the solvent.

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

[Preparation of thermosetting resin composition]
The thermosetting resin compositions (solid content 30% by mass) of Examples and Comparative Examples were prepared by blending raw materials according to the blending composition shown in Table 1. In addition, all the compounding compositions shown in Table 1 are solid content ratios.

Each component shown in the following Table 1 is as follows.
(A) Naphthalene skeleton epoxy: Epoxy resin having no naphthalene skeleton and having a naphthalene skeleton (manufactured by Nippon Kayaku Co., Ltd., product number NC-7000L).
(B) Phosphorus-containing epoxy: Phosphorus-modified epoxy resin (manufactured by Nippon Steel Chemical Co., Ltd., product number FX-305EK70). Use a methyl ethyl ketone solution with a solid content of 70% by mass.
(C) Carbodiimide-modified soluble polyamide: A carbodiimide-modified soluble polyamide synthesized by the above [Synthesis of carbodiimide compound]. A mixed solvent solution having a solid content of 11% by mass is used. The mixed solvent is a solvent obtained by mixing isopropyl alcohol and toluene at a mass mixing ratio of 4: 6.
(D) Phenoxy: Phenoxy resin (manufactured by Nippon Steel Chemical Co., Ltd., product number YP-40ASM40). A solution having a resin solid content concentration of 40% by mass.
(E) Addition type phosphazene: Phosphazene (manufactured by Otsuka Chemical Co., Ltd., product number SPB-100).
-(F) Flame-retardant filler: Organophosphate (manufactured by Clariant Japan, part number OP935).
(G) Reactive phosphazene: A phosphazene compound having a structure represented by [Chemical Formula 3] and containing three hydroxyphenyl groups in one molecule (product number SPH-100, manufactured by Otsuka Chemical Co., Ltd.).
(H) Reactive phosphazene: a compound having a structure represented by [Chemical Formula 3], wherein n is 3, and a compound containing one hydroxyphenyl group in one molecule and two hydroxys in one molecule Mixtures with compounds containing phenyl groups.
(I) Curing agent: dicyandiamide.
(J) Curing accelerator: 2-ethyl-4-methylimidazole (manufactured by Shikoku Chemicals Co., Ltd., product number 2E4MZ).
(K) Dye: Chuo Synthetic Chemical Co., Ltd., product number OIL BLACK SF.

[Evaluation test]
Using a comma coater and a dryer connected thereto, the thermoplastic resin compositions in the examples and comparative examples were applied to one side of a 12 μm thick copper foil and dried by heating. This obtained the resin sheet with metal foil which has a 40-micrometer-thick semi-hardened resin layer. The following evaluation tests were performed on these resin sheets with metal foil.

(Tensile modulus)
Two resin sheets with metal foil were stacked such that the resin layers were in contact with each other. These two resin sheets with metal foil were heat-pressed under conditions of 180 ° C. and 1 MPa to obtain a laminate. A sample for evaluation was obtained by removing all the copper foil in the outermost layer of the laminate by etching.

  The tensile modulus at 30 ° C. of this sample was measured using a viscoelastic spectrometer (manufactured by SII NanoTechnology Co., Ltd., product number DMS6100).

(Folding discoloration resistance)
Two resin sheets with metal foil are arranged so that the resin layers face each other, and a polyimide film with a thickness of 25 μm is arranged between the two resin sheets with metal foil, and in this state, the two resin sheets with metal foil And a polyimide film. In this state, a laminate was obtained by subjecting the resin sheet with metal foil and the poimide film to heat and pressure molding at 180 ° C. and 1 MPa for 1 hour. A sample for evaluation was obtained by removing all the copper foil in the outermost layer of the laminate by etching.

After the sample was bent 180 °, the state of discoloration of the mountain fold portion in the sample was visually observed and evaluated according to the following criteria.
◎ Almost no discoloration.
○ Slight discoloration is observed.
Δ Partial discoloration is observed.
× Discoloration is observed throughout the mountain fold.

(Flame retardance)
A copper foil having a thickness of 18 μm was stacked on the resin surface with the resin sheet with metal foil. The resin sheet with metal foil and the copper foil were subjected to heat and pressure molding at 180 ° C. and 1 MPa for 1 hour to obtain a laminate. A sample for evaluation was obtained by removing all the copper foil in the outermost layer of the laminate by etching.

  The flame retardancy of this sample was measured according to UL94, and those that satisfy VTM-0 were evaluated as “pass” and those that did not satisfy VTM-0 were evaluated as “fail” according to the flame retardancy criteria of 94 VTM. .

(Circuit fillability)
A flexible printed wiring board having a comb-like pattern of conductor wiring having a thickness of 35 μm, a line width of 100 μm, and a line spacing of 100 μm is prepared, and a resin sheet resin with metal foil is provided on the surface of the flexible printed wiring board on which the conductor wiring is formed. Layered. In this state, the flexible printed wiring board and the resin sheet with metal foil were heat-pressed for 1 hour under the conditions of 180 ° C. and 1 MPa to prepare a sample. The thickness of the cured resin layer in this sample was 20 μm from the conductor surface to the surface of the insulating layer.

  When the appearance of this sample is visually observed, the case where all the spaces between the conductor wirings are filled with the cured product of the resin layer is passed, and the portion not filled with the cured product of the resin layer is observed between the wires. Was rejected.

(Copper foil peel strength)
Two resin sheets with metal foil are arranged so that the resin layers face each other, and a polyimide film with a thickness of 25 μm is arranged between the two resin sheets with metal foil, and in this state, the two resin sheets with metal foil And a polyimide film. In this state, a sample for evaluation was obtained by heat-pressing the resin sheet with metal foil and the poimide film under the conditions of 180 ° C. and 1 MPa for 1 hour.

  The peel strength when the copper foil was peeled from the sample in the 90 ° direction was measured, and the case where the peel strength was 0.6 kN / m or more was evaluated as acceptable, and the other was evaluated as unacceptable.

(Solder heat resistance)
Two resin sheets with metal foil are arranged so that the resin layers face each other, and a polyimide film with a thickness of 25 μm is arranged between the two resin sheets with metal foil, and in this state, the two resin sheets with metal foil And a polyimide film. In this state, a sample for evaluation was obtained by heat-pressing the resin sheet with metal foil and the poimide film under the conditions of 180 ° C. and 1 MPa for 1 hour. The total thickness of the cured resin layer in this sample was 105 μm.

  This sample was immersed in a solder bath at 288 ° C. for 60 seconds and then pulled out of the solder bath. The appearance of the sample after this treatment was visually observed, and a case where no abnormality in appearance such as swelling or peeling was observed was evaluated as acceptable, and a case where an abnormality in appearance was observed was evaluated as unacceptable.

(Flexibility)
By patterning the copper foil in a flexible substrate provided with a polyimide film having a thickness of 25 μm and a copper foil having a thickness of 18 μm on one surface of the polyimide film, a flexible printed wiring board having a polyimide film and a conductor wiring was obtained. Resin sheets with metal foil were disposed on both sides of this flexible wiring board. In this state, the resin sheet with metal foil and the flexible wiring board were heated and pressed under conditions of 180 ° C. and 1 MPa for 1 hour, and a copper foil on both sides was etched to obtain a sample. The flexibility of this sample was measured.

  Flexibility is tested by the MIT method, and the measurement conditions are set to be R = 0.38 mm, the load is 500 g, and the rate is 175 times per minute. It was evaluated by the number of times.

(Migration resistance)
A flexible printed wiring board comprising a polyimide film having a thickness of 25 μm and a comb-like pattern-like conductor wiring having a thickness of 12 μm on the polyimide film, a line width of 100 μm, and a line spacing of 100 μm was prepared. The resin layer of the resin sheet with metal foil was overlaid on the surface of the flexible printed wiring board on which the conductor wiring was formed. In this state, the flexible printed wiring board and the metal were heat-press molded for 1 hour under the conditions of 180 ° C. and 1 MPa, and the outermost copper foil was removed by etching to obtain a sample for evaluation. In this sample, the thickness between the outer surface of the cured product of the resin layer and the surface of the conductor wiring was 34 μm.

  Under an environment of 85 ° C./85% RH, a voltage of 10 V was applied between both ends of the conductor wiring of the sample for 250 hours. Subsequently, the degree of migration was confirmed by visually observing this sample. The case where the occurrence of migration was not recognized was evaluated as acceptable, and the case where the occurrence of migration was observed was evaluated as failed.

(Bleed-out evaluation)
Two resin sheets with metal foil are arranged so that the resin layers face each other, and a polyimide film with a thickness of 25 μm is arranged between the two resin sheets with metal foil, and in this state, the two resin sheets with metal foil And a polyimide film. In this state, the resin sheet with metal foil and the poimide film were heated and pressed under conditions of 180 ° C. and 1 MPa for 1 hour, and the copper foil on both sides was etched to obtain a sample for evaluation. This sample was left in an environment of 85 ° C./85% RH for 250 hours, and then the sample was visually observed to determine the presence or absence of bleed out. As a result, a case where foreign matter was observed on the surface of the sample was evaluated as unacceptable, and a case where foreign matter was not observed on the surface was evaluated as acceptable.

DESCRIPTION OF SYMBOLS 1 Flexible printed wiring board 7 1st resin layer 8 2nd resin layer 9 Resin sheet with metal foil 10 Metal foil

Claims (6)

  Contains a phosphorus-containing epoxy resin, a first phosphazene compound that is not reactive with an epoxy group, a second phosphazene compound that is reactive with an epoxy group, and a carbodiimide-modified soluble polyamide and no insoluble particulate filler Thermosetting resin composition.   The thermosetting resin composition according to claim 1, wherein the second phosphazene compound contains phenoxyphosphazene having 1 to 2 phenolic hydroxyl groups in one molecule.   In the solid content ratio, 25 to 45% by mass of the phosphorus-containing epoxy resin, 2 to 12% by mass of the first phosphazene compound, 5 to 15% by mass of the second phosphazene compound, and 30 of the carbodiimide-modified soluble polyamide. The thermosetting resin composition according to claim 1, which is contained at a ratio of ˜60 mass%.   A semi-cured layer comprising a metal foil and a first resin layer, wherein the first resin layer is formed from the thermosetting resin composition according to any one of claims 1 to 3. A resin sheet with metal foil.   The resin sheet with metal foil according to claim 4, further comprising a second resin layer different from the first resin layer, interposed between the metal foil and the first resin layer.   A flexible printed wiring board provided with the insulating layer formed from the hardened | cured material of the thermosetting resin composition as described in any one of Claims 1 thru | or 3.

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