JP2012062346A - Thermosetting resin composition and interlayer adhesive film for printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosetting resin composition from which a cured product excellent in dimensional stability and an insulating layer excellent also in low-temperature meltability are obtained and which exhibits excellent stability, and an interlayer adhesive film for obtaining an insulating layer.SOLUTION: The thermosetting resin composition contains a polyimide resin (A) having a biphenyl skeleton directly linked to a 5-membered cyclic imide skeleton and having a content of the bisphenyl skeleton of 20-45 mass%, a logarithmic viscosity of 0.2-0.8 dl/g, and an acid value of 10-100, an epoxy resin (B), and an inorganic filler (C) having a specific surface area of 20-200 m/g. The interlayer adhesive film for a printed wiring board is obtained by applying the thermosetting resin composition onto a carrier film and drying it.

Description

  The present invention relates to a thermosetting resin composition having a cured product excellent in dimensional stability and an insulating layer excellent in low-temperature meltability and excellent in stability, and an interlayer adhesive film for obtaining an insulating layer.

  In recent years, there has been an increasing demand for thinner, lighter and higher mounting density semiconductor components, and the wiring density of circuit boards is expected to increase further in the future. As means for improving the wiring density, for example, a three-dimensional circuit is formed by stacking wiring boards. In the future, the number of laminated layers is expected to reach 10 layers or more. As the number of laminated layers increases, the generation of circuit strain stress due to the difference in thermal expansion between the insulating layer and the copper foil has been regarded as a problem. Has been demanded.

As a resin composition for obtaining an insulating layer having a low coefficient of thermal expansion, for example, a polybutadiene polyol compound having two or more alcoholic hydroxyl groups in one molecule and a diisocyanate compound are reacted to form a diisocyanate prepolymer. Polyimide resin obtained by reacting a basic acid dianhydride and a polyfunctional phenol compound having two or more phenolic hydroxyl groups in one molecule, an epoxy resin, and an inorganic packing having a specific surface area of 18 to 50 m ² / g An interlayer insulating resin composition containing an agent is disclosed (for example, see Patent Document 1). However, even the polyimide resin disclosed in Patent Document 1 has a high coefficient of thermal expansion, and the dimensional stability of the obtained insulating layer is not yet sufficient.

  In addition, the insulating layer is also required to melt at a low temperature. However, low linear expansion resins are generally poor in low meltability, and it has been difficult to obtain a resin composition that achieves both low linear expansion and low meltability.

International Publication No. 2008/153208 Pamphlet

  An object of the present invention is to obtain an insulating layer having a low coefficient of linear expansion and excellent in low-temperature meltability, and also excellent in dispersion stability of inorganic fine particles, and an insulating layer. It is to provide an interlayer adhesive film.

  As a result of intensive studies, the inventors of the present invention have a biphenyl skeleton as a polyimide resin in a specific ratio, a logarithmic viscosity of 0.2 to 0.8 dl / g, and an acid value of 10 to 100. By using a certain polyimide resin, an insulating layer excellent in low-temperature meltability is obtained, and furthermore, the linear expansion coefficient of the cured product of the insulating layer is low. Furthermore, as an inorganic filler, the filler described in Patent Document 1 is used. The inventors have found that a filler having a large specific surface area can be used, and have completed the present invention.

That is, the present invention has a biphenyl skeleton directly linked to a 5-membered ring imide skeleton, the content of the biphenyl skeleton is 20 to 45% by mass, and the logarithmic viscosity is 0.2 to 0.8 dl / g. A thermosetting resin comprising a polyimide resin (A) having an acid value of 10 to 100, an epoxy resin (B), and an inorganic filler (C) having a specific surface area of 20 to ²⁰⁰ m ² / g. A composition is provided.

  Moreover, this invention provides the interlayer adhesive film for printed wiring boards characterized by being obtained by apply | coating and drying the said thermosetting resin composition on a carrier film.

  Although the thermosetting resin composition of the present invention is excellent in low-temperature meltability after being B-staged, the cured product has a low coefficient of linear expansion and excellent dimensional stability. It is also excellent in heat resistance, dimensional stability, flame retardancy, wear resistance, insulation, adhesion, and mechanical properties (toughness, flexibility). It can be used in various fields by utilizing these performances. Specifically, engine peripheral parts, sliding parts, HDD sliding parts, voice coils, electromagnetic coils, coating agents for various films, insulation coatings for electric wires, heat resistance such as cooking devices, insulation Applications requiring coating properties: Fiber-reinforced composite materials such as carbon fiber prepregs, printed wiring boards, semiconductor insulating materials, coverlays, surface protection layers such as solder resists, build-up materials, prepreg resins, flexible displays Insulating materials, organic TFT insulating layers, buffer coatings, semiconductor coatings such as Low-k, polymer waveguides, semiconductor encapsulants, adhesives such as underfill, etc. Applications: solar cells, lithium batteries, capacitors, electricity Insulating layers such as double layer capacitors, electrode binders, various energy industrial materials such as separators; others, lasers It can be used for endless belts such as transfer belts and fixing belts for printers and copiers or coating agents, conductive films, binders for heat dissipation films, alignment films for color filters, overcoat films, etc. Especially for insulating layers such as multilayer printed wiring boards It can be suitably used for solder resist. Also, by using the interlayer adhesive film for printed wiring boards of the present invention, an insulating layer having a low coefficient of linear expansion of the cured product can be obtained while being melted at a low temperature at the time of crimping with a copper foil. It is suitably used as an adhesive film for forming an insulating layer.

  The polyimide resin (A) used in the present invention has a biphenyl skeleton content of 20 to 45 mass%, a relative viscosity of 0.2 to 0.8 dl / g, and an acid value of 10 to 100. When the content of the biphenyl skeleton is less than 20% by mass, it is not preferable because low linear expansion (dimensional stability) is hardly exhibited. When the content of the biphenyl skeleton is larger than 45% by mass, it is not preferable because solvent solubility and low-temperature meltability are hardly exhibited. The content of the biphenyl skeleton is preferably 25 to 40% by mass because a thermosetting resin composition having both low linear expansion and low temperature meltability is obtained, and more preferably 25 to 35% by mass.

  The content of the biphenyl structure is such that the molecular weight is 152 when the biphenyl structure is bonded to the polyimide resin main chain and the molecular weight is 150 when the biphenyl structure is bonded at 4 positions. It can be calculated from the ratio of the biphenyl structure to the weight.

  When the logarithmic viscosity of the polyimide resin (A) used in the present invention is less than 0.2 dl / g, it is not preferable because a cured product having sufficient strength cannot be obtained. When the logarithmic viscosity is larger than 0.8 dl / g, the low-temperature meltability is remarkably impaired. The logarithmic viscosity of the polyimide resin (A) is preferably 0.2 to 0.7 dl / g because a cured product having sufficient strength can be obtained and low-temperature meltability is exhibited. When calculating | requiring low temperature meltability, logarithmic viscosity has preferable 0.2-0.5 dl / g. When low linear expansion is required, the logarithmic viscosity is preferably 0.3 to 0.7 dl / g.

  Therefore, the polyimide resin (A) used in the present invention is preferably a polyimide resin having a biphenyl skeleton content of 25 to 40% by mass and a logarithmic viscosity of 0.2 to 0.7 dl / g.

In the present invention, the logarithmic viscosity of the polyimide resin was determined under the following conditions.
A polyimide resin was dissolved in N-methyl-2-pyrrolidone so that the resin concentration was 0.5 g / dl to obtain a resin solution. The solution viscosity of the resin solution and the solvent viscosity (viscosity of N-methyl-2-pyrrolidone) were measured at 30 ° C. with an Ubbelohde type viscosity tube, and the obtained measured values were obtained by applying the following formulas. .

Logarithmic viscosity (dl / g) = [ln (V1 / V2)] / V3
In the above formula, V1 represents the solution viscosity measured with an Ubbelohde type viscosity tube, and V2 represents the solvent viscosity measured with an Ubbelohde type viscosity tube. Here, V1 and V2 were determined from the time required for the resin solution and the solvent (N-methyl-2-pyrrolidone) to pass through the capillary of the viscosity tube. V3 is the polymer concentration (g / dl).

  Moreover, when the acid value of the polyimide resin (A) used in the present invention is smaller than 10, it is not preferable because the dispersibility and dispersion stability of the inorganic filler (C) are not sufficient. An acid value greater than 100 is not preferable because the physical properties of the coating film become brittle. The acid value is more preferably 15 to 90.

  Therefore, the polyimide resin (A) used in the present invention is a polyimide resin having a biphenyl skeleton content of 25 to 40% by mass, a logarithmic viscosity of 0.2 to 0.7 dl / g, and an acid value of 10 to 100. A polyimide resin having a biphenyl skeleton content of 25 to 35% by mass, a logarithmic viscosity of 0.2 to 0.7 dl / g, and an acid value of 15 to 90 is more preferable.

  The polyimide resin (A) includes, for example, a polyisocyanate compound (a1) having a biphenyl structure and / or an acid anhydride (a2) having a biphenyl structure, and a polyisocyanate compound (a3) other than (a1) as necessary. It can be easily obtained by reacting an acid anhydride (a4) other than (a2).

  Examples of the polyisocyanate compound (a1) having a biphenyl structure include 4,4′-diisocyanate-3,3′-dimethyl-1,1′-biphenyl, 4,4′-diisocyanate-3,3′-diethyl. -1,1'-biphenyl, 4,4'-diisocyanate-2,2'-dimethyl-1,1'-biphenyl, 4,4'-diisocyanate-2,2'-diethyl-1,1'-biphenyl, Examples include 4,4′-diisocyanate-3,3′-ditrifluoromethyl-1,1′-biphenyl, 4,4′-diisocyanate-2,2′-ditrifluoromethyl-1,1′-biphenyl, and the like.

  Examples of the acid anhydride (a2) having a biphenyl structure include biphenyl-3,3 ′, 4,4′-tetracarboxylic acid, biphenyl-2,3,3 ′, 4′-tetracarboxylic acid, and these Monoanhydrides, dianhydrides, and the like. These can be used alone or as a mixture of two or more.

  Examples of the polyisocyanate compound (a3) other than (a1) include aromatic polyisocyanates and aliphatic polyisocyanates other than (a1).

  Examples of the aromatic polyisocyanate other than (a1) include p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylene diisocyanate, m-xylene diisocyanate, 2,4-tolylene diisocyanate, and 2,6-tolylene diisocyanate. 4,4'-diphenylmethane diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, 3,3'-diethyldiphenyl-4,4'-diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, , 3-bis (α, α-dimethylisocyanatomethyl) benzene, tetramethylxylylene diisocyanate, diphenylene ether-4,4′-diisocyanate and naphthalene diisocyanate.

  Examples of the aliphatic polyisocyanate compound include hexamethylene diisocyanate, lysine diisocyanate, trimethylhexamethylenemethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, hydrogenated xylene diisocyanate, and norbornene diisocyanate.

  As the polyisocyanate compound, it is also possible to use an isocyanate prepolymer obtained by reacting the polyisocyanate compound and various polyol components in advance with an excess of isocyanate groups.

  The polyimide resin used in the present invention may have a branched structure in order to improve solvent solubility and compatibility with other resins. As the branching method, as the polyisocyanate compound, for example, a tri- or higher functional polyisocyanate compound having an isocyanurate ring, which is an isocyanurate body such as the diisocyanate compound, a burette body, an adduct body, an allohanate body of the diisocyanate, or Polymethylene polyphenyl polyisocyanate (crude MDI) or the like may be used.

  Examples of the acid anhydride (a4) other than (a2) include aromatic tricarboxylic acid anhydrides, alicyclic tricarboxylic acid anhydrides other than (a2), and tetracarboxylic acid anhydrides other than (a2). . Examples of aromatic tricarboxylic acid anhydrides other than (a2) include trimellitic anhydride and naphthalene-1,2,4-tricarboxylic acid anhydride.

  Examples of the alicyclic tricarboxylic acid anhydride include cyclohexane-1,3,4-tricarboxylic acid anhydride-3,4-anhydride, cyclohexane-1,3,5-tricarboxylic acid anhydride-3,5-anhydride, And cyclohexane-1,2,3-tricarboxylic acid anhydride-2,3-anhydride.

  Examples of tetracarboxylic acid anhydrides other than (a2) include pyromellitic dianhydride, benzophenone-3,3 ', 4,4'-tetracarboxylic dianhydride, diphenyl ether-3,3', 4. , 4'-tetracarboxylic dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, naphthalene-2,3,6,7-tetracarboxylic dianhydride, naphthalene-1,2 , 4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, decahydronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 4, 8-Dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8- Tetracarboxylic dianhydride, , 7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, phenanthrene- 1,3,9,10-tetracarboxylic dianhydride, berylene-3,4,9,10-tetracarboxylic dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3 , 4-dicarboxyphenyl) methane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 2,3-bis (3,4-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) sulfone Anhydride Bis (3,4-carboxyphenyl) ether dianhydride,

Ethylene glycol bisanhydro trimellitate, propylene glycol bis anhydro trimellitate, butanediol bis anhydro trimellitate, hexamethylene glycol bis anhydro trimellitate, polyethylene glycol bis anhydro trimellitate, polypropylene lenglycol bis Anhydro trimellitate, other alkylene glycol bisan hydroxy trimellitate, etc. are mentioned.

  The polyimide (A) used in the present invention is preferable because a polyimide resin having a benzophenone structure further exhibits heat resistance and low linear expansion. A polyimide resin having a benzophenone structure can be obtained, for example, by using benzophenone tetracarboxylic acid anhydride as an essential component in the production method.

  The content of the benzophenone structure is preferably from 1 to 30% by mass based on the mass of the polyimide resin, since a cured product having excellent heat resistance is obtained, and more preferably from 5 to 20% by mass is excellent in synthetic stability.

  The content of the benzophenone structure can be calculated from the ratio of the benzophenone structure to the total weight of the polyimide resin, with the molecular weight of the benzophenone structure having 4 bonding points to the polyimide resin main chain being 178.

In addition, the polyimide (A) used in the present invention is preferable because a polyimide resin having a tolylene structure bonded to the main chain at the 2- and 4-positions easily exhibits melt adhesion and low linear expansion. A polyimide resin having a tolylene structure bonded to the main chain at positions 2 and 4 can be obtained, for example, by using toluene diisocyanate as an essential component in the production method.
The content of the tolylene structure bonded to the main chain at the 2nd and 4th positions is based on the ratio of the tolylene structure to the total weight of the polyimide resin, assuming that the molecular weight of the tolylene structure bonded at the 2nd and 4th positions to the polyimide resin main chain is 150. Can be calculated.

  The content of the tolylene structure bonded to the main chain at positions 2 and 4 in the polyimide resin is preferably 1 to 20% by mass because it is excellent in synthetic stability, and 2 to 14% by weight is low in linear expansion and synthetic stability. More preferable.

  In the said manufacturing method, a polyisocyanate compound and the compound which has an acid anhydride group react. The ratio (ma) / (mb) of the number of moles of isocyanate groups in the polyisocyanate compound (ma) and the total number of moles of non-hydroxyl groups and carboxyl groups in the compound having an acid anhydride group (mb) is expressed as the molecular weight. A ratio of 0.7 to 1.2 is preferable, and a ratio of 0.8 to 1.2 is more preferable because a polyimide resin from which a large polyimide resin can be easily obtained and a cured product having excellent mechanical properties is obtained. Moreover, since it is easy to obtain the polyimide resin which is excellent in storage stability, the (ma) / (mb) is more preferably in the range of 0.9 to 1.1. In addition, when using together carboxylic anhydrides, such as trimellitic anhydride, said (mb) is the total number of moles of a hydroxyl-free group and a carboxyl group in all the carboxylic anhydrides.

  In the case of producing in a one-step reaction in the production method, for example, a reaction vessel is charged with a polyisocyanate compound and a compound having an acid anhydride group, and the reaction is allowed to proceed while decarboxylation by heating while stirring. .

  The reaction temperature can be in the range of 50 ° C. to 250 ° C., and is preferably performed at a temperature of 70 ° C. to 180 ° C. in terms of reaction rate and prevention of side reactions.

  The reaction is preferable because the stability of the resulting polyimide resin is improved when the reaction is performed until almost all isocyanate groups have reacted. Moreover, you may make it react by adding an alcohol and a phenol compound with respect to the isocyanate group which remains a little.

  In producing the polyimide resin (A) used in the present invention, it is preferable to use an organic solvent because a uniform reaction can proceed. Here, the organic solvent may be present after being present in the system in advance or may be introduced in the middle. In order to maintain an appropriate reaction rate, the proportion of the organic solvent in the system is preferably 98% by mass or less of the reaction system, more preferably 10 to 90% by mass, and more preferably 40 to 90% by mass. % Is more preferable. As such an organic solvent, since a compound containing an isocyanate group is used as a raw material component, an aprotic polar organic solvent having no active proton such as a hydroxyl group or an amino group is preferable.

  As the aprotic polar organic solvent, for example, polar organic solvents such as dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, sulfolane, and γ-butyrolactone can be used. In addition to the above solvents, ether solvents, ester solvents, ketone solvents, petroleum solvents and the like may be used as long as they are soluble. Various solvents may be mixed and used.

  In particular, use of dimethylacetamide is preferred from the viewpoint of reducing the amount of residual solvent when the coating film is dried and cured, and the solubility of the polyimide resin.

  Examples of ether solvents that can be used in the method for producing a polyimide resin used in the present invention include ethylene glycol dialkyl ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and ethylene glycol dibutyl ether; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, Polyethylene glycol dialkyl ethers such as diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, and triethylene glycol dibutyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, etc. Polyethylene glycol monoalkyl ether acetates such as diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triethylene glycol monomethyl ether acetate, triethylene glycol monoethyl ether acetate, triethylene glycol monobutyl ether acetate Alkyl ether acetates;

Propylene glycol dialkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dibutyl ether; dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dibutyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tripropylene glycol Polypropylene glycol dialkyl ethers such as propylene glycol dibutyl ether; propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate; Polypropylene glycol monoalkyl ether acetate such as triglycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol monobutyl ether acetate, tripropylene glycol monomethyl ether acetate, tripropylene glycol monoethyl ether acetate, tripropylene glycol monobutyl ether acetate Dialkyl ethers of copolymerized polyether glycols such as low molecular weight ethylene-propylene copolymers; monoacetate monoalkyl ethers of copolymerized polyether glycols; alkyl esters of copolymerized polyether glycols; Examples include ether glycol monoalkyl esters and monoalkyl ethers. It is.

  Examples of the ester solvent include ethyl acetate and butyl acetate. Examples of the ketone solvent include acetone, methyl ethyl ketone, and cyclohexanone. In addition, as the petroleum solvent, it is also possible to use toluene, xylene, other high-boiling aromatic solvents, and aliphatic and alicyclic solvents such as hexane and cyclohexane.

  Whether or not the polyimide resin (A) used in the present invention is dissolved in an organic solvent was determined by adding the polyimide resin concentration of the present invention to 10% by mass in the organic solvent and allowing to stand at 25 ° C. for 7 days. Then, it can carry out by observing an external appearance visually.

  The polyimide resin (A) used in the present invention may be a polyimide resin having a linear structure or a polyimide resin having a branched structure. Further, the copolymer component may have a polyester-modified polyesterimide or urethane-modified polyurethaneimide structure.

  Examples of the terminal structure of the polyimide resin (A) used in the present invention include structures such as carboxylic acid, carboxylic acid anhydride, isocyanate group, and amine group. As the terminal structure, the structure of the carboxylic acid or its anhydride is preferable because the stability of the polyimide resin itself of the present invention and the stability after blending with an organic solvent or another resin are good. When the terminal structure is a carboxylic acid or its anhydride structure, the acid value is a polyimide resin with a solid content acid value of 1 to 200, which makes it easy to handle, and a film or molded product with excellent mechanical strength and dimensional stability can be obtained. To preferred.

  The molecular weight of the polyimide resin (A) used in the present invention is preferably from 1,000 to 200,000, more preferably from 5,000 to 80,000 because a polyimide resin (A) that is easy to handle and a film and a molded product excellent in mechanical strength and dimensional stability are obtained. The molecular weight can be measured by GPC or quantitative determination of the terminal functional group.

In the present invention, the weight average molecular weight (Mw) was measured using a gel permeation chromatograph (GPC) under the following conditions.
Measuring device: Tosoh Corporation HLC-8320GPC, UV8320
Column: Super AWM-H × 2 manufactured by Tosoh Corporation Detector: RI (differential refractometer) and UV (254 nm)
Data processing: Tosoh Corporation EcoSEC-WorkStation
Measurement conditions: Column temperature 40 ° C
Solvent DMF
Flow rate 0.35 ml / min Standard: Calibration curve prepared with polystyrene standard sample Sample: 0.2% by weight DMF solution in terms of resin solid content filtered through a microfilter (injection volume: 10 μl)

  Moreover, the polyimide resin (A) used by this invention has a preferable polyimide resin which does not have an alkylene structure.

  The epoxy resin (B) used in the present invention preferably has two or more epoxy groups in the molecule. Examples of such epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resins, bisphenol S type epoxy resins, and bisphenol F type epoxy resins; biphenyl type epoxy resins; naphthalene type epoxy resins; phenol novolac epoxy resins and cresol novolac types. Epoxy resins, novolak type epoxy resins such as bisphenol type novolacs; epoxidized products of various dicyclopentadiene modified phenolic resins obtained by reacting dicyclopentadiene with various phenols; epoxy resins having a fluorene skeleton; 10- (2,5 -Dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide and the like, and a phosphorus-containing epoxy resin; neopentyl glycol di Aliphatic epoxy resins such as ricidyl ether and 1,6-hexanediol diglycidyl ether; 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis- (3,4-epoxycyclohexyl) adipate, etc. And alicyclic epoxy resins; and heterocycle-containing epoxy resins such as triglycidyl isocyanurate. Among them, at least one epoxy resin selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, and naphthalene type epoxy resin is obtained. It is preferable because the composition is excellent in meltability at low temperature while being expanded.

  By using at least one epoxy resin selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, and naphthalene type epoxy resin, the cured product has low linear expansion. And, the excellent meltability at low temperature is that the polyimide resin (A) has a biphenyl structure and the epoxy resin has a bisphenol A structure, a bisphenol F structure, a biphenyl structure, and a naphthalene structure, The inventors speculate that the epoxy resin prevents aggregation of the polyimide resin at the time of melting, and at the same time, the epoxy resin interacts closely after curing to form a dense cured state.

  The content of the epoxy resin (B) is 10 to 100% by mass with respect to 100 parts by mass of the polyimide resin (A), and the cured product has low linear expansion, and has excellent thermosetting properties at low temperatures. It is preferable from the resin composition obtained, 10-40 mass% is more preferable, 10-30 mass% is still more preferable.

  Moreover, since the viscosity of an epoxy resin (B) becomes a composition excellent in low temperature meltability, the epoxy resin whose viscosity in 150 degreeC is 12 Pa.s or less is preferable, and the epoxy resin of 10 Pa.s or less is more preferable.

The inorganic filler (C) used in the present invention has a specific surface area of 20 to ²⁰⁰ m ² / g. By using the inorganic filler (C), a cured product having a low coefficient of linear expansion and good heat resistance can be obtained. When the specific surface area is less than 20 m ² / g, the dispersion stability is deteriorated, and the surface smoothness as a coating film or an adhesive layer is deteriorated. For example, it is formed on an insulating material such as the present resin composition during a printed circuit board manufacturing process. It is not preferable because fine patterning is difficult to obtain in the copper circuit forming process. If the specific surface area is larger than 200 m ² / g, it is not preferable because it becomes difficult to disperse even small particles, the viscosity of the composition becomes high, and the effect of lowering linear expansion is difficult to obtain. The specific surface area is preferably 25~180m ² / g of the inorganic filler (C), 30~150m ² / g is more preferable.

  Examples of the inorganic filler (C) used in the present invention include silica and alumina. Among these, a cured product having excellent dimensional stability and improved heat resistance due to an increase in high-temperature elastic modulus can be obtained.

  The amount of the inorganic filler (C) added is based on the mass of the thermosetting resin composition of the present invention (100 total of polyimide resin (A), epoxy resin (B), and inorganic filler (C). 10 to 50% by mass) is preferable because a cured product having excellent dimensional stability and laser processability and good toughness can be obtained, and more preferably 10 to 40% by mass.

  The analysis of the specific surface area can be performed by a so-called BET method in which molecules having a known adsorption occupation area are adsorbed on liquid nitrogen and the specific surface area of the sample is determined from the amount of the molecules. The BET method by low-temperature low-humidity physical adsorption of inert gas is most often used. Further, when such an inorganic filler is blended in the resin composition, it is preferable that the inorganic filler is uniformly dispersed because the physical properties of the coating film are improved. As a dispersion method, various dispersion methods such as a bead mill, three rolls, two rolls, a homogenizer, meteor stirring, a fill mix dispersion, a high speed dispersion method, and a paint shaker method can be used. The particle diameter after dispersion is more preferably 5 μm or less, more preferably 1 μm or less, and even more preferably by dispersing to 300 nm or less, which is more preferable.

  Boron compounds such as boric acid and / or boric acid esters can be used in combination with the thermosetting resin composition of the present invention. Examples of such compounds include boric acid; trialkyl such as trimethyl borate, triethyl borate, tributyl borate, tri-n-octyl borate, tri (triethylene glycol methyl ether) borate ester, tricyclohexyl borate, and trimenthyl borate. Linear aliphatic borate esters typified by borate esters; aromatic borate esters such as tri-o-cresyl borate, tri-m-cresyl borate, tri-p-cresyl borate, triphenyl borate, tri Boric acid esters containing two or more boron atoms such as (1,3-butanediol) biborate, tri (2-methyl-2,4-pentanediol) biborate, trioctylene glycol diborate, etc. and containing a cyclic structure ; Polyvinyl alcohol borate ester Xylene glycol anhydrous boric acid to.

  Furthermore, phosphorus compounds such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide can also be added to the thermosetting resin composition of the present invention.

  When a compound other than the epoxy resin (B) is added to the thermosetting resin composition of the present invention, a thermosetting resin composition having good storage stability is obtained, and a cured coating film having excellent dimensional stability is obtained. Therefore, boric acid and linear aliphatic borate esters are preferable. Among the linear aliphatic borate esters, trialkyl borate esters having 4 to 20 carbon atoms are preferable, and tributyl borate (tributyl borate) is particularly preferable.

  Other thermosetting resin components can be further added to the thermosetting resin composition of the present invention. Specifically, a phenol compound, an isocyanate compound, a silicate, an alkoxysilane compound, a melamine resin, etc. are mentioned, for example.

  Preferred examples of the phenol compound include, for example, bisphenol compounds having two or more phenolic hydroxyl groups in one molecule such as bisphenol A, bisphenol F, and bisphenol S; hydroquinone, 4,4′-biphenol, 3,3′- 1 phenolic hydroxyl group such as dimethyl-4,4′biphenol, 3,3 ′, 5,5′-tetramethylbiphenol, 2,4-naphthalenediol, 2,5-naphthalenediol, 2,6-naphthalenediol A compound having two or more in the molecule, a phenol compound containing a phosphorus atom such as 10- (2,5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide; a phenol novolac resin; Cresol novolac resin, t-butylphenol Borac resin, dicyclopentagencresol novolak resin, dicyclopentagen phenol novolak resin, xylylene modified phenol novolak resin, naphthol novolak resin, trisphenol novolak resin, tetrakisphenol novolak resin, bisphenol A novolak resin, poly-p-vinylphenol Examples thereof include novolak type phenol resins such as resins, aminotriazine novolak type phenol resins, and phenol aralkyl resins. These phenol resins can be used alone or in combination of two or more. Among them, cured products from which 10- (2,5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide and aminotriazine novolac-type phenol resins are obtained have high heat resistance, flame resistance, and low linear expansion. However, it is preferable because the composition has excellent meltability at low temperatures.

  Examples of the isocyanate compound include aromatic isocyanate compounds, aliphatic isocyanate compounds, and alicyclic isocyanate compounds. Preferably, a polyisocyanate compound having two or more isocyanate groups in one molecule is preferable. A blocked isocyanate compound can also be used.

  Examples of the alkylalkoxysilane include alkyltrialkoxysilane and dialkyldialkoxysilane.

  Examples of the alkyltrialkoxysilane include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltributoxysilane, Examples thereof include phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, and phenyltributoxysilane.

  Examples of the dialkyl dialkoxysilane include dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldipropoxysilane, diethyldibutoxysilane, and diphenyldimethoxy. Silane, diphenyldiethoxysilane, diphenyldipropoxysilane, diphenyldibutoxysilane, methylethyldimethoxysilane, methylethyldiethoxysilane, methylethyldipropoxysilane, methylethyldibutoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane , Methylphenyldipropoxysilane, methylphenyldibutoxysilane, trimethylmethoxysilane, trimethyl ether Kishishiran, triethyl silane, triethyl silane, triphenyl methoxy silane, triphenyl ethoxy silane, and the like.

  Moreover, the condensate of alkyl alkoxysilane can also be used, for example, the condensate of the above-mentioned alkyl trialkoxysilane, the condensate of dialkyl dialkoxysilane, etc. are mentioned.

  As the melamine resin, for example, an alkoxylated melamine resin obtained by reacting a part or all of a methylol product obtained by reaction of a triazine ring-containing amino compound such as melamine or benzoguanamine with formaldehyde is used with an alcohol compound. be able to. As the alcohol compound used here, a lower alcohol having about 1 to 4 carbon atoms can be used. Specifically, a methoxymethylolated melamine resin, a butylated methylolated melamine resin, or the like can be used. The molecular structure may be completely alkoxylated, a methylol group may remain, or an imino group may remain.

  This alkoxylated melamine resin, in the thermosetting resin composition of the present invention, has the effect of preventing precipitation with time when boric acid and / or boric acid esters are added in addition to the improvement of heat resistance and physical properties as a crosslinking component. Yes, it improves the stability as a thermosetting resin composition.

  As the resin structure of the alkoxylated melamine resin, the methoxymethylolated melamine resin is preferable because of compatibility with the polyimide resin and good curability at the time of curing, and more preferably, a methoxymethylol having a methoxylation rate of 80% or more. A melamine resin is more preferable.

  The resin structure may be a polynuclear body by self-condensation. The degree of polymerization at this time is preferably about 1 to 5 in terms of compatibility and stability, and more preferably about 1.2 to 3.

  As the number average molecular weight of the alkoxylated melamine resin, those having a molecular weight of 100 to 10,000 can be used. Preferably, 300 to 2000 is preferable in terms of compatibility with the polyimide resin and curability at the time of curing, and more preferably 400 to 1000.

  As the alkoxylated melamine resin, even if melamine, benzoguanamine, formalin and alcohol are simultaneously charged and reacted, melamine or benzoguanamine and formalin are reacted in advance to obtain a methylolated melamine compound and then alkoxylated with the alcohol compound. May be.

  Specific examples of commercially available alkoxylated melamine resins include, for example, product Cymel 300, 301, 303, and 305 manufactured by Nippon Cytec Industries, as methoxymethylolated melamine resins. Examples of the methylol group-containing methoxymethylolated melamine resin include product Cymel 370 and 771 manufactured by Nippon Cytec Industries. Examples of the imino group-containing methoxylated melamine resin include commercial Cymel 325, 327, 701, 703, and 712 manufactured by Mitsui Cytec Co., Ltd. Examples of the methoxylated butoxylated melamine resin include product Cymel 232, 235, 236, 238, 266, 267, 285 manufactured by Nippon Cytec Industries. Examples of the butoxylated melamine resin include product Uban 20SE60 manufactured by Nippon Cytec Industries.

  The amount of the alkoxylated melamine resin used is 1 to 80 parts by mass, preferably 1 to 80 parts by mass with respect to a total of 100 masses of the polyimide resin (A) and boron compound (B) because of excellent mechanical properties and high TG. 50 mass parts and 1-30 mass parts are preferable.

  Further, the thermosetting resin composition of the present invention includes a binder resin such as polyester, phenoxy resin, PPS resin, PPE resin, polyarylene resin, phenol resin, melamine resin, alkoxysilane curing agent, polybasic acid anhydride, cyanate compound. Curing such as curing agents or reactive compounds such as melamine, dicyandiamide, guanamine and derivatives thereof, imidazoles, amines, phenols having one hydroxyl group, organic phosphines, phosphonium salts, quaternary ammonium salts, photocationic catalysts, etc. It is also possible to add a defoaming agent, leveling agent, slip agent, wetting improver, anti-settling agent, flame retardant, antioxidant, ultraviolet absorber, etc. as a catalyst, curing accelerator, further filler, and other additives .

  The thermosetting resin composition of the present invention is preferably a composition in which the cured product has a linear expansion coefficient of 50 ppm / ° C. or less when the composition is cured.

  In addition, various fillers, organic pigments, inorganic pigments, extender pigments, rust inhibitors and the like can be added to the thermosetting resin composition of the present invention as necessary. These may be used alone or in combination of two or more.

  Examples of the filler include barium sulfate, barium titanate, silicon oxide powder, finely divided silicon oxide, silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, mica, and alumina. Is mentioned.

  As the filler, those having various particle sizes can be used, and can be added to such an extent that the physical properties of the present resin and its composition are not impaired. Such an appropriate amount is in the range of about 5 to 80% by mass, and preferably used after being uniformly dispersed. As a dispersion method, it is possible to carry out dispersion by a known roll, bead mill, high-speed dispersion or the like, and the surface of the particles may be modified in advance with a dispersion treatment agent.

  Examples of the organic pigment include azo pigments; copper phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green, and quinacridone pigments.

  Examples of the inorganic pigment include chromates such as chrome lead, zinc chromate and molybdate orange; ferrocyanides such as bitumen, titanium oxide, zinc white, bengara, iron oxide; metal oxides such as chromium carbide green, Cadmium yellow, cadmium red; metal sulfides such as mercury sulfide; selenides; sulfates such as lead sulfate; silicates such as ultramarine; carbonates, cobalt biored; phosphates such as manganese purple; aluminum powder, zinc dust Metal powders such as brass powder, magnesium powder, iron powder, copper powder and nickel powder; carbon black and the like.

  In addition, any of other coloring, rust prevention, and extender pigments can be used. These may be used alone or in combination of two or more.

  The thermosetting resin composition of the present invention can be dried or cured by heating at 100 to 300 ° C. after coating or molding.

  The substrate used in the method for forming the coating film can be used without any particular limitation. Examples of the substrate include plastic, metal, wood, glass, inorganic material, and composite materials thereof.

  The interlayer adhesive film for printed wiring boards of the present invention is characterized by having a layer formed of a thermosetting resin composition on a carrier film. Such an adhesive film can illustrate the form of the film (adhesive film) which consists of a layer (A layer) and a support body film (B layer) of the thermosetting resin composition of this invention, for example.

  The adhesive film is prepared according to various methods, for example, by preparing a resin varnish obtained by dissolving the thermosetting resin composition of the present invention in an organic solvent, applying the resin varnish to a support film, and heating or blowing hot air. It can manufacture by drying an organic solvent and forming a resin composition layer.

  The support film (B layer) serves as a support when the adhesive film is produced, and is finally peeled off or removed in the production of the printed board. Examples of the support film include polyolefins such as polyethylene and polyvinyl chloride, polyethylene terephthalate (hereinafter sometimes abbreviated as “PET”), polyesters such as polyethylene naphthalate, polycarbonate, and release paper and copper foil. The metal foil etc. can be mentioned. In addition, when using copper foil as a support body film, it can remove by etching with etching liquid, such as ferric chloride and cupric chloride. The support film may be subjected to a release treatment in addition to a mat treatment and a corona treatment, but it is more preferable that the release treatment is performed in consideration of releasability. Although the thickness of a support film is not specifically limited, Usually, it is 10-150 micrometers, Preferably it is used in 25-50 micrometers.

  Organic solvents for preparing the varnish include, for example, ketones such as acetone, methyl ethyl ketone, cyclohexanone, acetates such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, carbitol acetate, cellosolve, butyl Examples thereof include carbitols such as carbitol, aromatic hydrocarbons such as toluene and xylene, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and gamma butyrolactone. Two or more organic solvents may be used in combination.

  The drying conditions are not particularly limited, but the drying is performed so that the content of the organic solvent in the resin composition is usually 5% by mass or less, preferably 3% by mass or less. The specific drying conditions vary depending on the curability of the resin composition and the amount of the organic solvent in the varnish. For example, in a varnish containing 30 to 60% by mass of an organic solvent, it is usually 3 to 13 minutes at 80 to 120 ° C. It can be dried to some extent. Those skilled in the art can appropriately set suitable drying conditions by simple experiments.

  The thickness of the resin composition layer (A layer) can usually be in the range of 5 to 500 μm. The preferred range of the thickness of the A layer varies depending on the use of the adhesive film, and when used for manufacturing a multilayer flexible circuit board by the build-up method, the thickness of the conductor layer forming the circuit is usually 5 to 70 μm. The thickness of the A layer corresponding to the layer is preferably in the range of 10 to 100 μm.

  The A layer may be protected with a protective film. By protecting with a protective film, it is possible to prevent dust and the like from being attached to the surface of the resin composition layer and scratches. The protective film is peeled off during lamination. As the protective film, the same material as the support film can be used. Although the thickness of a protective film is not specifically limited, Preferably it is the range of 1-40 micrometers.

  The adhesive film obtained using the thermosetting resin composition of the present invention can be suitably used particularly for the production of a multilayer printed board. Below, the method to manufacture a printed circuit board is demonstrated. The adhesive film obtained by using the thermosetting resin composition of the present invention can be suitably laminated on a printed board with a vacuum laminator. The printed circuit board used here is mainly a conductor layer patterned on one or both sides of a substrate such as a fiber reinforced prepreg such as an epoxy substrate or a glass epoxy substrate, a polyester substrate, a polyimide substrate, a polyamideimide substrate, or a liquid crystal polymer substrate. (Circuit) As a matter of course, a multilayer printed circuit board in which a circuit and an insulating layer are alternately formed and a circuit is formed on one side or both sides can be used for further multilayering. In addition, from the viewpoint of adhesion of the insulating layer to the circuit board, the surface of the circuit should have been previously roughened with a surface treatment agent such as hydrogen peroxide / sulfuric acid or MEC Etch Bond (MEC Co., Ltd.). preferable.

  Commercially available vacuum laminators include, for example, a vacuum applicator manufactured by Nichigo Morton, a vacuum pressurizing laminator manufactured by Meiki Seisakusho, a roll dry coater manufactured by Hitachi Techno Engineering Co., Ltd., Hitachi AIC ( A vacuum laminator manufactured by Co., Ltd. can be mentioned.

In the lamination, when the adhesive film has a protective film, the protective film is removed, and then the adhesive film is pressure-bonded to the circuit board while being pressurized and heated. The laminating conditions include pre-heating the adhesive film and the circuit board as required, laminating at a pressure of preferably 70 to 140 ° C., a pressure of pressure of preferably 1 to 11 kgf / cm ² and laminating under a reduced pressure of an air pressure of 20 mmHg or less. preferable. The laminating method may be a batch method or a continuous method using a roll.

  After laminating the adhesive film on the circuit board, it is cooled to around room temperature and the support film is peeled off. Next, the thermosetting resin composition laminated on the circuit board is cured by heating. The conditions for heat curing are usually selected in the range of 150 to 220 ° C. for 20 to 180 minutes, more preferably in the range of 160 to 200 ° C. for 30 to 120 minutes. When the support film has a release layer or a release layer such as silicon, the support film can be peeled after the thermosetting resin composition is heat-cured or after heat-curing and punching.

  After the insulating layer, which is a cured product of the thermosetting resin composition, is formed, the via holes and through holes are formed by drilling the circuit board as necessary using a method such as drilling, laser, plasma, or a combination thereof. May be. In particular, drilling with a laser such as a carbon dioxide laser or a YAG laser is generally used.

  Next, surface treatment of the insulating layer (cured product of the thermosetting resin composition) is performed. The surface treatment can employ a method used in a desmear process, and can be performed in a form that also serves as a desmear process. As a chemical used in the desmear process, an oxidizing agent is generally used. Examples of the oxidizing agent include permanganate (potassium permanganate, sodium permanganate, etc.), dichromate, ozone, hydrogen peroxide / sulfuric acid, nitric acid, and the like. Preferably, an alkaline permanganate solution (for example, potassium permanganate, sodium hydroxide aqueous solution of sodium permanganate), which is an oxidizer widely used for roughening the insulating layer in the production of multilayer printed wiring boards by the build-up method. It is preferable to carry out the treatment using A treatment with a swelling agent can also be performed before the treatment with the oxidizing agent. Further, after the treatment with an oxidizing agent, neutralization treatment with a reducing agent is usually performed.

  After the surface treatment, a conductor layer is formed by plating on the surface of the insulating layer. The conductor layer can be formed by a method combining electroless plating and electrolytic plating. Alternatively, a plating resist having a pattern opposite to that of the conductor layer can be formed, and the conductor layer can be formed only by electroless plating. After the conductor layer is formed, the peel strength of the conductor layer can be further improved and stabilized by annealing at 150 to 200 ° C. for 20 to 90 minutes.

  As a method for forming a circuit by patterning the conductor layer, for example, a subtractive method or a semi-additive method known to those skilled in the art can be used. In the case of the subtractive method, the thickness of the electroless copper plating layer is 0.1 to 3 μm, preferably 0.3 to 2 μm. An electroplating layer (panel plating layer) is formed thereon with a thickness of 3 to 35 μm, preferably 5 to 20 μm, an etching resist is formed, and etching is performed with an etching solution such as ferric chloride or cupric chloride. After forming a conductor pattern by this, a circuit board can be obtained by peeling an etching resist. In the case of the semi-additive method, after forming the electroless copper plating layer with an electroless copper plating layer thickness of 0.1 to 3 μm, preferably 0.3 to 2 μm, a pattern resist is formed, and then the electrolytic copper A circuit board can be obtained by peeling after plating.

  A film in which the support film is replaced with a heat-resistant resin layer (heat-resistant resin film), that is, a film comprising the thermosetting composition layer (A layer) and the heat-resistant resin layer (C layer) of the present invention is a flexible circuit board. Can be used as a base film. A film comprising the thermosetting resin composition layer (A layer), the heat-resistant resin layer (C layer) and the copper foil (D layer) of the present invention can be used as a base film of a flexible circuit board as well. In this case, the base film has a layer structure in the order of A layer, C layer, and D layer. In the base film as described above, the heat-resistant resin layer is not peeled off and constitutes a part of the flexible circuit board.

  A film in which an insulating layer (A ′ layer) made of a cured product of the thermosetting resin composition of the present invention is formed on a heat-resistant resin layer (C layer) can be used as a base film for a single-sided flexible circuit board. Moreover, it consists of a film having a layer structure in the order of A ′ layer, C layer and A ′ layer, and A ′ layer, C layer and copper foil (D layer). Similarly, a film having a layer structure can be used as a base film for a double-sided flexible circuit board.

  Examples of the heat-resistant resin used for the heat-resistant resin layer include a polyimide resin, an aramid resin, a polyamideimide resin, and a liquid crystal polymer. In particular, a polyimide resin and a polyamideimide resin are preferable. Moreover, on the characteristic used for a flexible circuit board, the breaking strength is 100 MPa or more, the breaking elongation is 5% or more, the thermal expansion coefficient between 20 and 150 ° C. is 40 ppm or less, and the glass transition temperature is 200 ° C. or more or the decomposition temperature is 300 ° C. It is preferable to use the above heat resistant resin.

  As the heat-resistant resin satisfying such characteristics, a heat-resistant resin that is commercially available in the form of a film can be suitably used. For example, a polyimide film “Upilex-S” manufactured by Ube Industries, Ltd., Toray DuPont Co., Ltd. ) Polyimide film "Kapton", Kaneka Chemical Co., Ltd. polyimide film "Apical", Teijin Advanced Films Ltd. "Aramika", Kuraray Co., Ltd. liquid crystal polymer film "Bexstar", Sumitomo Bakelite Co., Ltd. A polyether ether ketone film “Sumilite FS-1100C” and the like are known.

  The thickness of the heat-resistant resin layer is usually 2 to 150 μm, preferably 10 to 50 μm. As the heat-resistant resin layer (C layer), a surface-treated layer may be used. Examples of the surface treatment include dry treatment such as mat treatment, corona discharge treatment and plasma treatment, chemical treatment such as solvent treatment, acid treatment and alkali treatment, sand blast treatment and mechanical polishing treatment. In particular, from the viewpoint of adhesion to the A layer, it is preferable that plasma treatment is performed.

  A base film for a single-sided flexible circuit board comprising an insulating layer (A ′) and a heat-resistant resin layer (C) can be produced as follows. First, similarly to the adhesive film described above, a resin varnish prepared by dissolving the thermosetting resin composition of the present invention in an organic solvent is prepared, and this resin varnish is applied on a heat-resistant resin film, and heated or blown with hot air, etc. The organic solvent is dried to form a thermosetting resin composition layer. Conditions such as the organic solvent and drying conditions are the same as those for the adhesive film. The thickness of the resin composition layer is preferably in the range of 5 to 15 μm.

  Next, the thermosetting resin composition layer is dried by heating to form an insulating layer of the thermosetting resin composition. The conditions for heat curing are usually selected in the range of 150 to 220 ° C. for 20 to 180 minutes, more preferably in the range of 160 to 200 ° C. for 30 to 120 minutes.

  The production of a base film of a double-sided flexible circuit board film consisting of three layers of an insulating layer (A ′ layer), a heat-resistant resin layer (C) layer and a copper foil (D layer) is made of a heat-resistant resin layer (C layer) and a copper foil. A resin composition may be formed on a copper-clad laminated film made of (D layer) and manufactured in the same manner as described above. Examples of the copper clad laminated film include a cast method two-layer CCL (Copper-clad laminate), a sputtering method two-layer CCL, a laminate method two-layer CCL, and a three-layer CCL. The thickness of the copper foil is preferably 12 μm or 18 μm.

  Commercially available two-layer CCL includes Espanex SC (manufactured by Nippon Steel Chemical Co., Ltd.), Neoprex I <CM>, Neoprex I <LM> (Mitsui Chemicals), S'PERFLEX (Sumitomo Metal Mining Co., Ltd.) Nikaflex F-50VC1 (manufactured by Nikkan Kogyo Co., Ltd.) and the like are mentioned as the commercially available three-layer CCL.

  The production of a base film for a double-sided flexible circuit board film comprising three layers of an insulating layer (A ′ layer), a heat-resistant resin layer (C layer) and an insulating layer (A ′ layer) can be carried out as follows. First, in the same manner as the adhesive film described above, a resin varnish prepared by dissolving the thermosetting resin composition of the present invention in an organic solvent is prepared, and this resin varnish is applied onto a support film, and organic by heating or hot air blowing, etc. The solvent is dried to form a resin composition layer. Conditions such as the organic solvent and drying conditions are the same as those for the adhesive film. The thickness of the resin composition layer is preferably in the range of 5 to 15 μm.

  Next, this adhesive film is laminated on both surfaces of the heat resistant resin film. Lamination conditions are the same as described above. Moreover, if the resin composition layer is previously provided on one side of the heat-resistant film, the lamination may be only on one side. Next, the resin composition layer is cured by heating to form an insulating layer that is a layer of the resin composition. The conditions for heat curing are usually selected in the range of 150 to 220 ° C. for 20 to 180 minutes, more preferably in the range of 160 to 200 ° C. for 30 to 120 minutes.

  A method for producing a flexible circuit board from the base film for the flexible circuit board will be described. In the case of a base film composed of an A ′ layer, a C layer, and an A ′ layer, first, after heat curing, a circuit board is drilled by a method such as drilling, laser, or plasma to form a through hole for conduction on both sides. . In the case of a base film composed of an A ′ layer, a C layer, and a D layer, holes are formed by the same method to form via holes. In particular, drilling with a laser such as a carbon dioxide laser or a YAG laser is generally used.

  Next, a surface treatment of the insulating layer (resin composition layer) is performed. About surface treatment, it is the same as that of the case of the adhesive film mentioned above. After the surface treatment, a conductor layer is formed by plating on the surface of the insulating layer. The formation of the conductor layer by plating is the same as in the case of the adhesive film described above. After the conductor layer is formed, the peel strength of the conductor layer can be further improved and stabilized by annealing at 150 to 200 ° C. for 20 to 90 minutes.

  Next, the conductor layer is patterned to form a circuit to obtain a flexible circuit board. When a base film composed of an A layer, a C layer, and a D layer is used, a circuit is also formed on the copper foil that is the D layer. As a circuit formation method, for example, a subtractive method or a semi-additive method known to those skilled in the art can be used. Details are the same as in the case of the adhesive film described above.

  The single-sided or double-sided flexible circuit board obtained in this way can be produced as a multilayer flexible circuit board by using the adhesive film of the present invention, for example, as described above.

  The resin composition of the present invention is also useful as a material for forming a stress relaxation layer between a semiconductor and a substrate substrate. For example, in the same manner as described above, all or part of the uppermost insulating layer of the substrate substrate is formed by the adhesive film obtained by using the resin composition of the present invention, and the resin is connected by connecting the semiconductor. A semiconductor device in which a semiconductor and a substrate substrate are bonded via a cured product of the composition can be manufactured. In this case, the thickness of the resin composition layer of the adhesive film is appropriately selected within a range of 10 to 1000 μm. With the resin composition of the present invention, a conductor layer can be formed by plating, and a circuit pattern can also be produced by simply forming a conductor layer by plating on an insulating layer for stress relaxation provided on a substrate substrate. Is possible.

  EXAMPLES Next, an Example is shown and this invention is demonstrated further in detail. Unless otherwise specified, “parts” and “%” are based on weight.

Synthesis Example 1 [Synthesis of Polyimide Resin (A)]
To a flask equipped with a stirrer, a thermometer and a condenser, 213.2 g of DMAC (dimethylacetamide), 6.28 g (0.036 mol) of TDI (tolylene diisocyanate), TODI (4,4′-diisocyanate-3,3 '-Dimethyl-1,1'-biphenyl) 39.3 g (0.143 mol), TMA (trimellitic anhydride) 29.1 g (0.151 mol), BTDA (benzophenone-3,3', 4,4) ′ -Tetracarboxylic dianhydride) and 12.2 g (0.038 mol) were added, the temperature was raised to 150 ° C. over 1 hour while paying attention to heat generation while stirring, and the reaction was carried out at this temperature for 5 hours. I let you. The reaction proceeded with the foaming of carbon dioxide, and the system became a brown transparent liquid. A polyimide resin solution (resin composition in which the polyimide resin was dissolved in DMAC) having a resin solid content of 20% with a viscosity of 2 Pa · s at 25 ° C. and a solution acid value of 16 (KOHmg / g) was obtained. This is abbreviated as polyimide resin (A1) solution. In addition, the solid content acid value of the resin calculated from the value was 64 (KOHmg / g). Moreover, it was the weight average molecular weight 10,000 as a result of the measurement of a gel permeation chromatography (GPC).

  The obtained polyimide resin (A1) solution was coated on a KBr plate, and the infrared absorption spectrum of the sample obtained by volatilizing the solvent was measured. As a result, 2270 cm-1 which is the characteristic absorption of the isocyanate group completely disappeared, and 725 cm- Characteristic absorption of the imide ring was confirmed at 1, 1780 cm <-1> and 1720 cm <-1>. The amount of carbon dioxide generated was 15.8 g (0.36 mol), which was monitored by the change in the flask content weight. From this, it is concluded that the total amount of 0.36 mol, which is the total amount of isocyanate groups, has been converted to imide bonds and amide bonds.

  Table 1 shows the blending amount of the raw material of the polyimide resin (A1), the content of the biphenyl skeleton, the logarithmic viscosity, the weight average molecular weight, and the solid content acid value.

Synthesis Examples 2, 4, 5, 6, 8, 9 [Synthesis of polyimide resin (A) and comparative polyimide resin (a)]
A solution of polyimide resins (A2), (A4) and a polyimide resin (A5), polyimide resins for comparison (a1), (a3) and ( A solution of a4) was obtained. As in Synthesis Example 1, the biphenyl skeleton content, logarithmic viscosity, weight average molecular weight and solid content acid value are shown in Table 1.

Synthesis Example 3 and Synthesis Example 7 [Synthesis of polyimide resin (A3) and polyimide resin (a2)]
Polyimide resin in the same manner as in Synthesis Example 1 except that BPDA (BPDA: biphenyl-3,3 ′, 4,4′-tetracarboxylic anhydride) is used instead of BTDA and the blending ratio shown in Table 1 is used. A solution of (A3) was obtained. As in Synthesis Example 1, the biphenyl skeleton content, logarithmic viscosity, weight average molecular weight and solid content acid value are shown in Table 1.

第１表の脚注
測定不能：合成中、析出物が沈殿し、均一溶液として得られなかった為、測定できなかった。

Footnotes in Table 1 Inability to measure: Precipitates precipitated during synthesis and could not be obtained as a uniform solution, so measurement was not possible.

Examples 1-11 and Comparative Examples 1-7
The thermosetting resin compositions 1 to 11 and comparative thermosetting resin compositions 1 'to 7' of the present invention were obtained with the formulations shown in Tables 2 to 4. The TG, linear expansion coefficient, and meltability of the cured product obtained were evaluated. The results are shown in Tables 2-5.

-Evaluation of TG and linear expansion coefficient of cured product Preparation of test piece The thermosetting resin composition was coated on a tin substrate so that the film thickness of the coating film obtained after curing was 30 μm. Next, this coated plate was dried with a dryer at 50 ° C. for 30 minutes, with a dryer at 100 ° C. for 30 minutes, and with a dryer at 200 ° C. for 60 minutes to form a coating film (film). After cooling to room temperature, the coating film (film) was cut into a predetermined size, isolated from the substrate, and used as a measurement sample.

2. Method for measuring TG and linear expansion coefficient
Using a thermal analysis system TMA-SS6000 manufactured by Seiko Electronics Co., Ltd., measurement was performed by the TMA (Thermal Mechanical Analysis) method under the conditions of a sample length of 10 mm, a heating rate of 10 ° C./min, and a load of 30 mN. In addition, TG calculated | required the inflection point from the temperature-dimension change curve by TMA measurement, and made the temperature TG. Furthermore, the temperature range used for the linear expansion coefficient was determined from the displacement of the sample length at 20 to 150 ° C. The higher the TG, the better the heat resistance, and the smaller the linear expansion coefficient, the better the dimensional stability.

-Evaluation of meltability Create adhesive film
Next, the thermosetting resin composition is uniformly applied on a PET film (thickness 125 μm) with an applicator so that the thickness of the resin composition layer after drying is 25 μm, and dried at 100 ° C. for 5 minutes. An adhesive film was obtained.

2. Melt adhesion test of adhesive film The above-mentioned adhesive film is in contact with copper on an electrolytic copper foil (thickness 18 μm, surface roughness: M surface Rz 7.4 μm, S surface Ra 0.21 μm) heated to 120 ° C. in advance. And then hot-pressed at a pressure of 0.1 MPa for 1 minute. Thereafter, the PET film was peeled off, and the resin composition was further cured by heating at 200 ° C. for 60 minutes. The test piece was subjected to a tape peeling test in accordance with JIS K 5400 8.5.2 (adhesive cross-cut tape method), and evaluated as melt adhesion according to the following evaluation criteria.

A: After the main curing, the tape is peeled off, and the area of the defective part is less than 5% with respect to the test execution area.
○: After the main curing, the tape is peeled off and the area of the defective part is 5% or more with respect to the test execution area.
X: The resin did not adhere to the copper foil at all when the PET film was peeled off before the main curing.

Footnotes in Table 1 TDI: 2,4-tolylene diisocyanate TODI: 4,4'-diisocyanate-3,3'-dimethyl-1,1'-biphenyl TMA: trimellitic anhydride BTDA: benzophenone tetracarboxylic anhydride BPDA: biphenyl-3,3 ', 4,4'-tetracarboxylic anhydride

Footnotes of Table 2 to Table 850S: DIC Co., Ltd. bisphenol A type liquid epoxy resin Epicron 850-S (epoxy equivalent 188 g / eq)
EXA-4710: Naphthalene type epoxy resin manufactured by DIC Corporation Epicron EXA-4710 (epoxy equivalent 173 g / eq)
N-680: Cresol novolac type epoxy resin manufactured by DIC Corporation Epicron N-680 (epoxy equivalent 211 g / eq)
YX4000: manufactured by Mitsubishi Chemical Corporation biphenyl type epoxy resin YX4000 (epoxy equivalent 187 g / eq)
HCA-HQ: 10- (2,5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide

Claims (14)

It has a biphenyl skeleton directly connected to a 5-membered ring imide skeleton, the content of the biphenyl skeleton is 20 to 45% by mass, the logarithmic viscosity is 0.2 to 0.8 dl / g, and the acid value is 10 to 100. A thermosetting resin composition comprising a polyimide resin (A), an epoxy resin (B), and an inorganic filler (C) having a specific surface area of 20 to ²⁰⁰ m ² / g.   The polyimide resin (A) has a biphenyl skeleton content of 25 to 40% by mass, a logarithmic viscosity of 0.2 to 0.7 dl / g, and an acid value of 10 to 100. Thermosetting resin composition.   The epoxy resin (B) is at least one epoxy resin selected from the group consisting of bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, biphenyl type epoxy resins and naphthalene type epoxy resins. Item 2. The thermosetting resin composition according to item 1.   The thermosetting resin composition according to claim 1, wherein the content of the epoxy resin (B) is 10 to 100 parts by mass with respect to 100 parts by mass of the polyimide resin (A).   The thermosetting resin composition according to claim 1, wherein the polyimide resin (A) is a polyimide resin further having a benzophenone structure.   The thermosetting resin composition according to claim 1 or 5, wherein the polyimide resin (A) is a polyimide resin further having a tolylene structure.   The thermosetting resin composition according to claim 1, wherein the polyimide resin (A) is a polyimide resin having no alkylene structure.   The thermosetting resin composition according to claim 1, wherein the epoxy resin (B) has a viscosity at 150 ° C. of 12 Pa · s or less. The thermosetting resin composition according to claim 1, wherein the inorganic filler (C) has a specific surface area of 25 to 180 m ² / g.   Content of the said inorganic filler (C) is 5-50 mass parts with respect to a total of 100 weight part of a polyimide resin (A), an epoxy resin (B), and an inorganic filler (C). The thermosetting resin composition according to 1.   The thermosetting resin composition according to claim 1, wherein the inorganic filler (C) is silica.   Furthermore, the thermosetting resin composition of Claim 1 containing a melamine resin (D).   The thermosetting resin composition according to claim 1, wherein the cured product has a linear expansion coefficient of 50 ppm / ° C. or less. An interlayer adhesive film for printed wiring boards, comprising a layer formed of the thermosetting resin composition according to claim 1 on a carrier film.