JP2006342334A - Curable resin composition, prepreg, substrate, metal foil-clad laminate, metal foil with resin and printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed wiring board having sufficient adhesiveness between a wiring and a substrate and sufficient heat resistance and to provide a curable resin composition forming prepreg having sufficiently suppressed breakages or cracks. <P>SOLUTION: The curable resin composition for the printed wiring board comprises (a) a component of an acrylic polymer having a monomer unit derived from glycidyl (meth)acrylate, (b) a component of an epoxy resin, (c) a component of a phenol resin, (d) a component of a curing promoter and (e) a component of a thiol compound. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a curable resin composition, a prepreg, a substrate, a metal foil-clad laminate, a resin-coated metal foil, and a printed wiring board.

  With the downsizing and high performance of electronic devices typified by mobile phones, printed wiring boards mounted therein are strongly required to have high density including thinning and multilayering. In order to increase the density of the printed wiring board, a prepreg that is semi-cured by impregnating a glass cloth serving as a base material with a thermosetting resin such as an epoxy resin or a polyimide resin is suitably employed as the substrate material. This prepreg is also used in an embodiment of a metal foil-clad laminate obtained by placing metal foils such as copper foils on both main surfaces and heating and pressing.

  Densification of the printed wiring board can be achieved more suitably by reducing the thickness of the glass cloth as a base material, for example, by making the thickness to 30 μm or less. Prepreg has been developed and marketed recently. As a result, although the density of printed wiring boards is increasing, it is difficult to ensure sufficient heat resistance, insulation reliability, and wiring-to-board adhesion. It has become to.

  As one method for producing a printed wiring board, there is a method of patterning a metal foil of a metal foil-clad laminate obtained by laminating a metal foil on one side or both sides of an insulating substrate. In general, the metal foil used for the metal foil-clad laminate has a roughened surface on the side bonded to the substrate in order to ensure high adhesion to the substrate. As a result, the thickness of the substrate is locally reduced due to the unevenness on the surface of the metal foil. However, as described above, when the prepreg, which is the substrate material of the printed wiring board, is thinned and the overall thickness of the substrate is reduced, it becomes clear that the insulation reliability particularly in the locally thinned portion is lowered. It was. Therefore, there is a demand for a technique for suppressing the roughening of the metal foil to some extent while maintaining high insulation reliability of the printed wiring board and at the same time sufficiently increasing the adhesion between the wiring and the substrate.

  As a means intended to improve the adhesion between the copper foil and the substrate in the copper clad laminate, for example, in Patent Document 1, a hydroxyl group is imparted to the surface of the copper foil, and the copper foil and the substrate are coupled via a coupling agent. Means for laminating materials have been proposed.

  By the way, a prepreg using a thin glass cloth, for example, a glass cloth of 50 μm or less as a base material, is likely to be broken or cracked during handling as compared with the case of using a conventional thick glass cloth. This is due to the high flexibility of the glass cloth as the base material. When the prepreg is broken or cracked, peeling between the glass cloth and the impregnated resin occurs. The bending and cracking of these prepregs and the separation between the glass cloth and the resin become defects in the prepreg, which can cause defective molding of the laminated board using this prepreg and poor insulation of the printed wiring board. Further, with the prepreg being bent and cracked, the resin powder also falls off from the main surface and end surface of the prepreg. The dropped resin powder is not preferable because it can be mixed as a foreign substance when forming the laminated plate.

In order to prevent the prepreg from being broken or cracked, for example, Patent Document 2 reports a laminate in which a glass cloth is impregnated with a vinyl ester resin composition.
JP-A-5-229060 JP 2002-128977 A

  However, when the present inventors have studied in detail the conventional methods including those described in Patent Documents 1 and 2 described above, such a conventional method is not sufficient between the wiring or the metal foil and the substrate. It was proved difficult to satisfy both of ensuring sufficient adhesion and sufficiently preventing the prepreg from being broken or cracked at the same time. In the future, when trying to further increase the density of the printed wiring board, the conventional method is sufficient to ensure sufficiently good wiring or metal foil-substrate adhesion, and to prevent the prepreg from being folded or cracked. It became clear that it was difficult to suppress.

  Therefore, the present invention has been made in view of the above circumstances, a printed wiring board having sufficiently excellent wiring-to-substrate adhesion and sufficient heat resistance, and a prepreg capable of sufficiently suppressing folding and cracking. An object is to provide a curable resin composition that can be formed, and a prepreg, a substrate, a metal foil-clad laminate, a metal foil with resin, and a printed wiring board using the curable resin composition.

  In order to achieve the above object, the present invention provides (a) component: an acrylic polymer having monomer units derived from glycidyl (meth) acrylate, (b) component: epoxy resin, and (c) component: phenol resin. , (D) component: A hardening accelerator and (e) component: The curable resin composition for printed wiring boards containing a thiol compound is provided.

  This curable resin composition is a printed wiring board having sufficiently excellent wiring-to-substrate adhesion and sufficient heat resistance, and can sufficiently suppress folding and cracking, that is, sufficiently excellent flexibility. A prepreg having can be formed. Although the factor which the curable resin composition of this invention has this effect is not clarified in detail at present, the present inventors consider the following factors. However, the factor is not limited to this.

  That is, the factor that improves the flexibility is mainly the blending of the acrylic polymer that is the component (a), and the factor that improves the adhesion between the wiring and the substrate is the thiol compound that is the component (e). It is thought that there was blended. And it is speculated that blending all of the above-mentioned components (a) to (e) raises both the flexibility and the adhesiveness to a sufficiently high level.

  Moreover, the curable resin composition of this invention provided with the said structure is excellent in heat resistance. Therefore, prepregs, metal foil-clad laminates, printed wiring boards and the like produced using this curable resin composition have excellent heat resistance during processing such as solder heat resistance and handling.

  In the curable resin composition of the present invention, the component (a) preferably has 1 to 20% by mass of a monomer unit derived from glycidyl (meth) acrylate based on the total amount. As a result, the curable resin composition is further excellent in heat resistance and insulation properties and can form a prepreg having higher flexibility.

  In the curable resin composition of the present invention, the weight average molecular weight of the component (a) is preferably 30000 or more. By adjusting the weight average molecular weight in this way, the curable resin composition can further enhance the flexibility of the cured product.

  In the curable resin composition of the present invention, from the viewpoint of imparting more excellent flexibility to the cured product, the blending ratio of the component (a) is 10 masses based on the total solid content in the curable resin composition. % Or more is preferable. From the same viewpoint, in the curable resin composition of the present invention, the component (b) preferably has two or more epoxy groups per molecule. Furthermore, from the same viewpoint, in the curable resin composition of the present invention, the component (c) preferably has two or more phenolic hydroxyl groups per molecule.

  In the curable resin composition of the present invention, the molar ratio of the phenolic hydroxyl group in component (c) to the epoxy group in component (b) (number of moles of phenolic hydroxyl group / number of moles of epoxy group) is 0.5 to 1. The component (c) is preferably blended so as to be 5. Thereby, the curable resin composition of this invention exists in the tendency which has the effect that the further outstanding heat resistance, adhesiveness, etc. are expressed.

  In the curable resin composition of the present invention, the component (d) is preferably an imidazole compound. By carrying out like this, the curable resin composition of this invention can improve the storage stability further.

  In the curable resin composition of the present invention, the component (e) is preferably one or more thiol compounds selected from the group consisting of alkylthiols, phenylthiols, and thiol coupling agents. When these thiol compounds are used, the effect that the adhesiveness between metal foil-board | substrate (resin) or wiring-board | substrate (resin) improves more can be show | played.

  The present invention provides a prepreg having a fiber substrate and the above-described curable resin composition impregnated therein. The present invention also provides a substrate obtained by heating and pressing the prepreg, and further comprising a metal foil-clad laminate comprising the substrate and a metal foil provided on at least one surface of the substrate. provide. Since these prepregs, substrates, and metal foil-clad laminates are formed using the curable resin composition of the present invention, they are unlikely to break or crack. Furthermore, the printed wiring board produced using these prepregs, substrates, and metal foil-clad laminates is sufficiently excellent in adhesion between the wiring and the substrate.

  Moreover, this invention provides the metal foil with resin provided with the resin film which consists of the above-mentioned curable resin composition, and the metal foil provided on the at least one surface of the said resin film. This metal foil with resin is excellent in heat resistance and has sufficiently high adhesion between the wiring and the substrate. Moreover, this metal foil with resin is sufficiently excellent in flexibility.

  The present invention provides a printed wiring board comprising the substrate and a wiring pattern provided on at least one surface of the substrate and made of metal. Since the printed wiring board of this invention uses the hardened | cured material of the above-mentioned curable resin composition for an insulation part, it shows the adhesiveness between wiring-board | substrate sufficiently excellent. Moreover, this printed wiring board has high heat resistance.

  According to the present invention, a printed wiring board having sufficiently excellent wiring-to-substrate adhesion and sufficient heat resistance, a curable resin composition capable of forming a prepreg capable of sufficiently suppressing folding and cracking, and A prepreg, a substrate, a metal foil-clad laminate, a resin-coated metal foil, and a printed wiring board using the curable resin composition can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios. Further, “(meth) acrylate” in the present specification means “acrylate” and “methacrylate” corresponding thereto.

  FIG. 1 is a partial perspective view showing a preferred embodiment of the prepreg of the present invention. A prepreg 100 shown in FIG. 1 is a sheet-like prepreg composed of a fiber base material and a curable resin composition impregnated therein.

  The fiber base material in the prepreg 100 is a flexible fiber base material that can be bent arbitrarily, and the thickness thereof is preferably 100 μm or less. Thereby, when it combines with the curable resin composition of the specific composition which is mentioned later, the flexibility of the board | substrate obtained increases synergistically, and it becomes very easy to bend | fold arbitrarily. In order to further increase the flexibility of the substrate, the thickness is more preferably 50 μm or less, further preferably 40 μm or less, and particularly preferably 30 μm or less. On the other hand, the lower limit of the thickness of the fiber substrate is not particularly limited, but is preferably 5 μm or more, and more preferably 10 μm or more. Here, by using the fiber base material, the dimensional change accompanying heating, moisture absorption, etc. in the manufacturing process of the substrate is sufficiently small.

  The form of the fiber base material can be appropriately selected from those generally used when producing metal foil-clad laminates and multilayer printed wiring boards, but usually fiber base materials such as woven fabrics and nonwoven fabrics are used. . The fibers constituting the fiber substrate include glass, alumina, asbestos, boron, silica alumina glass, silica glass, tyranno, silicon carbide, silicon nitride, zirconia, and other inorganic fibers, aramid, polyetheretherketone, polyetherimide , Organic fibers such as polyethersulfone, carbon and cellulose, or mixed papers thereof. Among these, glass fiber is preferable. In particular, glass cloth (glass fiber woven fabric) is preferably used as the fiber base material.

  The curable resin composition in the prepreg 100 includes (a) component: an acrylic polymer having monomer units derived from glycidyl (meth) acrylate, (b) component: epoxy resin, (c) component: phenol resin, It contains (d) component: a curing accelerator and (e) component: a thiol compound.

((A) component)
The acrylic polymer having a monomer unit derived from glycidyl (meth) acrylate as the component (a) is not particularly limited as long as it has a monomer unit derived from glycidyl (meth) acrylate as an essential component. Glycidyl (meth) acrylate usually generates a polymer by addition polymerization of its (meth) acrylic group by generating radicals.

  In the acrylic polymer as the component (a), as the monomer unit other than the monomer unit derived from glycidyl (meth) acrylate, for example, a monomer derived from alkyl (meth) acrylate which may have a substituent other than glycidyl group Units are listed. In the alkyl (meth) acrylate, the alkyl group is preferably an alkyl group having 1 to 20 carbon atoms which may have a substituent. Examples of the substituent for the alkyl group include an alicyclic group, a hydroxyl group, and a nitrogen-containing cyclic group.

  Examples of the alkyl (meth) acrylate include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, isobutyl acrylate, ethylene glycol methyl ether acrylate, and acrylic acid. Cyclohexyl, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, isobornyl acrylate, amide acrylate, isodecyl acrylate, octadecyl acrylate, lauryl acrylate, allyl acrylate, N-vinylpyrrolidone acrylate, methyl methacrylate , Ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, isobutyl methacrylate, ethyl methacrylate Glycol methyl ether, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, isobornyl methacrylate, methacrylic acid amide, isodecyl methacrylate, octadecyl methacrylate, lauryl methacrylate, allyl methacrylate, N methacrylate -Vinylpyrrolidone and dimethylaminoethyl methacrylate are mentioned. These are used singly or in combination of two or more.

  The acrylic polymer as the component (a) preferably has 1 to 20% by mass, preferably 1 to 15% by mass of the monomer unit derived from glycidyl (meth) acrylate based on the total amount of the component (a). It is more preferable. If it is less than 1% by mass, the heat resistance tends to decrease, and if it exceeds 20% by mass, the flexibility tends to decrease.

  (A) The weight average molecular weight of a component is preferable in it being 30000 or more, and it is more preferable in it being 30000-2 million. If the weight average molecular weight of the acrylic polymer is less than 30,000 or more than 2,000,000, the flexibility of the prepreg or the substrate tends to decrease. Here, said weight average molecular weight is a value measured by gel permeation chromatography (GPC) analysis, and means a standard polystyrene equivalent value. The GPC analysis can be performed, for example, using “GL8300 MDT-5” (trade name, manufactured by Hitachi Chemical Co., Ltd.) as a column and tetrahydrofuran (THF) as an eluent.

  The acrylic polymer as component (a) is obtained, for example, by copolymerizing glycidyl alkyl (meth) acrylate with another monomer copolymerizable therewith. By adjusting the copolymerization ratio at the time of copolymerization, an acrylic polymer having monomer units derived from glycidyl (meth) acrylate within a predetermined range based on the total amount of component (a) can be obtained. Moreover, you may obtain and use a commercial item for the acrylic polymer which is (a) component. The commercially available product has, for example, a monomer unit derived from glycidyl (meth) acrylate in a range of 1 to 20% by mass based on the total amount of the component (a), and a weight average molecular weight of 30,000 or more “HTR860P3” (Manufactured by Nagase ChemteX Corporation, trade name, epoxy value 3.05).

  In addition, the acrylic polymer may have a monomer unit derived from acrylonitrile or the like in addition to glycidyl (meth) acrylate or an alkyl (meth) acrylate which may have a substituent other than the glycidyl group.

  The acrylic polymer as component (a) is obtained, for example, by radical polymerization using a radical polymerization initiator that generates radicals. Radical polymerization initiators include persulfates such as azobisisobutyronitrile (AIBN), tert-butyl perbenzoate, benzoyl peroxide, lauroyl peroxide, potassium persulfate, cumene hydroperoxide, t-butyl hydroperoxide Dicumyl peroxide, di-t-butyl peroxide, 2,2′-azobis-2,4-dimethylvaleronitrile, t-butyl perisobutyrate, t-butyl perpivalate, hydrogen peroxide / ferrous salt, Examples thereof include persulfate / sodium acid sulfite, cumene hydroperoxide / ferrous salt, benzoyl peroxide / dimethylaniline, and the like. These may be used alone or in combination of two or more.

  As the component (a), acrylic polymers having the same weight average molecular weight, the same type of monomer units, and the same proportion of monomer units derived from glycidyl (meth) acrylate may be used alone, and the weight average molecular weights are different from each other. Two or more kinds of acrylic polymers, acrylic polymers having different types of monomer units, and / or acrylic polymers having glycidyl (meth) acrylate-derived monomer units in different proportions may be used.

  In the curable resin composition, the blending ratio of the acrylic polymer as the component (a) is preferably 10% by mass or more based on the total solid content in the curable resin composition, and is 10 to 60% by mass. More preferably. When the blending ratio of the acrylic polymer is less than 10% by mass, the flexibility of the cured product of the curable resin composition tends to decrease and the heat resistance tends to decrease. Moreover, when the blending ratio of the acrylic polymer exceeds 60% by mass, voids tend to remain in the fiber base material such as glass cloth when the prepreg is formed.

((B) component)
The epoxy resin as the component (b) is preferably an epoxy resin composed of a polyepoxy compound having two or more epoxy groups per molecule as a crosslinkable functional group. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin. And alicyclic epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, hydantoin type epoxy resins, isocyanurate type epoxy resins, and aliphatic chain epoxy resins. These epoxy resins may be halogenated or hydrogenated. These epoxy resins may be used alone or in combination of two or more. Moreover, these epoxy resins may be synthesized by a conventional method, or commercially available products may be obtained.

(Component (c))
The phenol resin as component (c) is preferably a polyfunctional phenol resin having two or more phenolic hydroxyl groups per molecule as a crosslinkable functional group. Examples of the phenolic resin include phenolic compounds such as bisphenol A, bisphenol F, bisphenol S, and polyvinylphenol, and phenolic compounds such as phenol, cresol, alkylphenol, catechol, bisphenol A, and bisphenol S, and formaldehyde, salicylaldehyde, and the like. Examples include condensates with aldehydes (that is, novolak-type phenol resins), and halides thereof. These phenol resins can be used individually by 1 type or in combination of 2 or more types. Moreover, these phenol resins may be synthesized by a conventional method, or commercially available products may be obtained.

  In the curable resin composition, the blending ratio of the phenol resin as the component (c) is the molar ratio of the phenolic hydroxyl group in the component (c) to the epoxy group in the component (b) (number of moles of phenolic hydroxyl group / epoxy group). The blending ratio is preferably such that the number of moles) is 0.5 to 1.5.

(Component (d))
The curing accelerator as the component (d) is not particularly limited as long as it has a catalytic function that promotes the curing reaction between the components (a) to (c). Examples of the curing accelerator include, but are not limited to, amine compounds, imidazole compounds, organic phosphorus compounds, alkali metal compounds, alkaline earth metal compounds, quaternary ammonium salts, and the like. Moreover, these hardening accelerators may be used individually by 1 type, and may be used in combination of 2 or more type.

  In these, it is preferable to mix | blend an imidazole compound as a hardening accelerator from a viewpoint of storage stability. Examples of the imidazole compound include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 2- Heptadecylimidazole, 4,5-diphenylimidazole, 2-methylimidazoline, 2-phenylimidazoline, 2-undecylimidazoline, 2-heptadecylimidazoline, 2-isopropylimidazole, 2,4-dimethylimidazole, 2-phenyl-4 -Methylimidazole, 2-ethylimidazoline, 2-isopropylimidazoline, 2,4-dimethylimidazoline, 2-phenyl-4-methylimidazoline, 1-cyanoethyl-2-methylimidazole, 1-sia Ethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2- Feirimidazolium trimellitate, 2,4-diamino-6- [2'-undecylimidazolyl- (1 ')]-ethyl-s-triazine, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl Examples include -4-methyl-5-hydroxymethylimidazole, imidazole whose imino group is masked with acrylonitrile, phenylene diisocyanate, toluidine isocyanate, naphthalene diisocyanate, methylene bisphenyl isocyanate, and melamine acrylate. It is. These imidazole compounds are used alone or in combination of two or more.

  0.01-5 mass parts is preferable with respect to 100 mass parts of epoxy resins which are (b) components, and, as for the mixture ratio of the hardening accelerator in curable resin composition, 0.01-3 mass parts is more preferable. If the blending ratio of the curing accelerator is less than 0.01 parts by mass, insufficient curing tends to occur, and if it exceeds 5 parts by mass, the storage stability of the curable resin composition tends to decrease.

  (D) The hardening accelerator which is a component may be synthesize | combined by a conventional method, and a commercial item may be obtained.

((E) component)
The thiol compound as the component (e) is not particularly limited, but is preferably one or more thiol compounds selected from the group consisting of alkyl thiols, phenyl thiols, and thiol coupling agents.

  Specific examples of the thiol compound include n-butyl mercaptan, 1-decanethiol, entanethiol, hinokitiol, 2-methoxybenzenethiol, thiophenol, 1-naphthalenethiol, p-nitrothiophenol, 1-octanethiol, Examples thereof include 1-pentanethiol, 1-propanethiol, o-aminothiophenol, 2-benzothiazolethiol, 1-butanethiol, 2-hydroxyethyl mercaptan, and γ-mercaptopropyltrimethoxysilane. Among these, γ-mercaptopropyltrimethoxysilane is preferable from the viewpoint of more effectively exerting the effects of the present invention. These thiol compounds are used alone or in combination of two or more. Moreover, these thiol compounds may be synthesized and / or prepared by a conventional method, and commercially available products may be obtained.

  The mixing ratio of the component (e) in the curable resin composition is preferably 0.05 to 10 parts by mass, more preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the epoxy resin (b). . When the blending ratio of the component (e) is less than 0.05 parts by mass, the adhesion between the wiring or metal foil and the insulating substrate tends to decrease, and when it exceeds 10 parts by mass, the heat resistance and the like decrease. There is a tendency.

  In addition to the components described above, the curable resin composition may include a crosslinking agent such as isocyanate and melamine, an inorganic filler such as silica, a conductive particle, a coupling agent, a pigment, a leveling agent, and an antifoam as necessary. An agent, an ion trap agent and the like may be contained.

  The curable resin composition of the present embodiment contains the above components (a) to (e) inseparably, so that the metal foil-clad laminate using the metal foil-substrate and wiring of a printed wiring board are used. -Give sufficiently good adhesion between the substrates. For example, for the copper foil-clad laminate using the curable resin composition of the present embodiment, when the peel strength between the copper foil and the substrate is measured by a predetermined method, the value becomes 0.8 kN / m or more, More preferable is 1.2 kN / m or more. Here, the predetermined method is a method described below.

  First, a prepreg is prepared by impregnating a glass cloth having a thickness of 0.04 mm with a curable resin composition so that the mass ratio of the solid content in the curable resin composition to the glass cloth is 7:10. . Next, a copper foil having a thickness of 18 μm and a 10-point average surface roughness (Rz) of 2.0 to 3.0 is disposed on both sides of the prepreg, and further heated at 170 ° C. and 4.0 MPa for 90 minutes from both sides. And pressurization is performed to obtain a double-sided copper-clad laminate. The copper foil of this double-sided copper clad laminate is partially etched to form a 1 mm wide copper foil line. Next, the copper foil line is peeled off at a speed of 50 mm / min in the direction of 90 ° with respect to the bonding surface, the load at that time is measured, and the maximum load is peeled off to be the strength.

  In addition, the curable resin composition of the present embodiment imparts sufficiently excellent flexibility to the dried product and the cured product due to the combined action of the components (a) to (e) described above. Furthermore, the curable resin composition of the present embodiment can form a cured product having high heat resistance.

  The prepreg 100 can be manufactured by, for example, impregnating a fiber base material with a varnish in which a curable resin composition is dissolved or dispersed in a solvent, and removing the solvent from the varnish by heating at 80 ° C. to 200 ° C. . In the prepreg 100, the solvent used in the varnish may remain, but 80% by mass or more of the solvent contained in the varnish is preferably removed. The varnish is a fiber base material in such a ratio that the amount of the curable resin composition in the varnish is 30 to 80% by mass based on the total mass of the curable resin composition and the fiber base material in the varnish. It is preferable to impregnate.

  The solvent used when varnishing the above-mentioned thermosetting resin composition is not particularly limited. Examples of the solvent include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, aromatic hydrocarbons such as toluene, xylene, and mesitylene, alcohols such as methanol, ethanol, and butanol, ethyl cellosolve, butyl cellosolve, and ethylene glycol. Monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethers such as carbitol, butyl carbitol, esters such as methoxyethyl acetate, ethoxyethyl acetate, butoxyethyl acetate, ethyl acetate, propylene glycol monomethyl ether acetate, etc. Ether acetates, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2- The solvent of the nitrogen Motorui such as pyrrolidone and the like. These may be used individually by 1 type and may be used in combination of 2 or more type.

  In addition, when curable resin composition itself has fluidity | liquidity, it is not necessary to varnish using a solvent. In this case, after impregnating the fiber base material with the curable resin composition, it is preferable to heat at a predetermined temperature until the curable resin composition does not flow.

  FIG. 2 is a partial cross-sectional view showing a preferred embodiment of the metal foil-clad laminate of the present invention. A metal foil-clad laminate 200 shown in FIG. 2 includes a substrate 30 obtained by heating and pressing one prepreg 100 and two metal foils 10 provided in close contact with both surfaces of the substrate 30. The

The metal foil-clad laminate 200 is obtained, for example, by stacking metal foils on both sides of the prepreg 100 and heating and pressurizing the metal foil to cure the curable resin composition in the prepreg 100. The heating at this time is preferably performed at a temperature in the range of 100 to 250 ° C, more preferably 100 to 200 ° C. The pressurization is preferably performed at a pressure in the range of 0.5 MPa to 20 MPa, more preferably 1 MPa to 8 MPa (10 kgf / cm ^{2 to} 80 kgf / cm ² ).

  As the metal foil 10, a copper foil or an aluminum foil is generally used, but a copper foil is preferable. As the copper foil, one having a thickness of 3 to 200 μm, which is usually used for a copper clad laminate, can be used, but in order to increase the flexibility of the metal foil clad laminate, the thickness is 3 to 18 μm. More preferably. Alternatively, nickel, nickel-phosphorus, nickel-tin alloy, nickel-iron alloy, lead, lead-tin alloy, etc. are used as intermediate layers, and a 0.5-15 μm copper layer and a 10-300 μm copper layer are provided on both sides. Alternatively, a composite foil having a three-layer structure or a composite foil having a two-layer structure in which aluminum and copper foil are combined can be used.

  The embodiment of the metal foil-clad laminate is not limited to the above aspect. For example, a plurality of prepregs 100 may be used to make the substrate a multilayer fiber reinforced resin layer, or a metal foil may be provided only on one side of the substrate.

  The metal foil-clad laminate of the present embodiment exhibits excellent solder heat resistance. For example, when this metal foil-clad laminate is immersed in a solder bath at 288 ° C., 60 seconds or more elapse after the immersion until the occurrence of swelling in the metal foil-clad laminate is recognized, and more preferably 180 seconds. More than has passed.

  The metal foil with resin of the present embodiment includes a resin film made of the curable resin composition described above and a metal foil provided on at least one surface of the resin film. Such a metal foil with resin is obtained by applying a curable resin composition or a varnish of the curable resin composition on a metal foil similar to the metal foil 10 described above, and heating at a predetermined temperature. Alternatively, a resin film obtained by previously forming a curable resin composition into a film shape may be placed on a metal foil and heated and pressurized at a predetermined temperature and a predetermined pressure to produce a resin-coated metal foil.

  FIG. 3 is a partial cross-sectional view showing a preferred embodiment of the printed wiring board of the present invention. A printed wiring board 300 shown in FIG. 3 is mainly composed of the substrate 30 and the wiring pattern 11 formed on both surfaces of the substrate 30 and formed of patterned metal foil. A plurality of through holes 70 are formed through the substrate 30 in a direction substantially perpendicular to the main surface, and a metal plating layer 60 having a predetermined thickness is formed on the hole wall of the through hole 70. . The printed wiring board 300 is obtained by forming a wiring pattern on the metal foil-clad laminate 200 described above. The wiring pattern can be formed by a conventionally known method such as a subtractive method. The printed wiring board 300 is particularly preferably used as a so-called flexible printed wiring board.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

Example 1
After blending the following components (a) to (e), mixing and stirring the mixture, adding methyl ethyl ketone thereto, adjusting the viscosity at 25 ° C. to 700 cP, the printed circuit board thermosetting resin composition A varnish was obtained.
(A) Component: 15 parts by mass of HTR860P3 (acrylic polymer containing glycidyl acrylate, manufactured by Nagase ChemteX Corporation, trade name) in terms of resin solids,
(B) component: Epicoat 5051 (brominated bisphenol A type epoxy resin, manufactured by Japan Epoxy Resin Co., Ltd., trade name, epoxy group equivalent 600 to 650 g / eq) in 100 parts by mass of resin solids,
(C) Component: 20 parts by mass of VP 6371 (novolac type phenol resin, manufactured by Hitachi Chemical Co., Ltd., trade name, phenolic hydroxyl group equivalent of 104 to 108 g / eq) in terms of resin solids,
(D) Component: 0.5 part by mass of 2E4MZ (imidazole compound, manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name) as a curing accelerator,
(E) Component: 2 parts by mass of γ-mercaptopropyltrimethoxysilane as a thiol compound.

(Example 2)
(A) The varnish of the thermosetting resin composition for printed wiring boards was changed in the same manner as in Example 1 except that the blending amount of the component was changed to 15 parts by mass with resin solids and 120 parts by mass with resin solids. Obtained.

(Example 3)
After blending the following components (a) to (e), mixing and stirring the mixture, adding methyl ethyl ketone thereto, adjusting the viscosity at 25 ° C. to 700 cP, the printed circuit board thermosetting resin composition A varnish was obtained.
(A) Component: 30 parts by mass of HTR860P3 (acrylic polymer containing glycidyl acrylate, manufactured by Nagase ChemteX Corporation, trade name) in terms of resin solids,
(B) component: Epicoat 828 (bisphenol A type epoxy resin, manufactured by Japan Epoxy Resin Co., Ltd., trade name, epoxy group equivalent 184 to 194 g / eq) in 100 parts by mass of resin solids,
(C) component: Fireguard 2000 (brominated bisphenol A, manufactured by Teijin Chemicals Ltd., trade name, phenolic hydroxyl group equivalent: 274 to 278 g / eq) in resin solids of 150 parts by mass,
(D) Component: 0.5 part by mass of 2E4MZ (imidazole compound, manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name) as a curing accelerator,
(E) Component: 1 part by mass of γ-mercaptopropyltrimethoxysilane as a thiol compound.

Example 4
(A) The varnish of the thermosetting resin composition for printed wiring boards was changed in the same manner as in Example 3 except that the blending amount of the component was changed to 30 parts by mass with resin solids and 250 parts by mass with resin solids. Obtained.

(Example 5)
(E) Varnish of thermosetting resin composition for printed wiring boards in the same manner as in Example 2 except that 2 parts by mass of γ-mercaptopropyltrimethoxysilane was used instead of 2 parts by mass of o-aminothiophenol. Got.

(Example 6)
(E) As in Example 2, except that 2 parts by mass of γ-mercaptopropyltrimethoxysilane was used instead of 1 part by mass of γ-mercaptopropyltrimethoxysilane and 1 part by mass of o-aminothiophenol. Thus, a varnish of a thermosetting resin composition for a printed wiring board was obtained.

(Comparative Example 1)
A varnish of a thermosetting resin composition for a printed wiring board was obtained in the same manner as in Example 1 except that the component (a) and the component (e) were not blended.

(Comparative Example 2)
(A) The varnish of the thermosetting resin composition for printed wiring boards was obtained like Example 1 except not mix | blending a component.

(Comparative Example 3)
(E) The varnish of the thermosetting resin composition for printed wiring boards was obtained like Example 1 except not mix | blending a component.

[Preparation of prepreg and metal foil-clad laminate]
The varnishes prepared in the above Examples and Comparative Examples were each made into 0.04 mm thick glass cloth “# 1037” (trade name, manufactured by Asahi Schwer, Inc.), and the mass ratio between the solid content of the varnish and the glass cloth was After impregnation with an impregnation coating machine so as to be 7:10, the solvent was removed by drying with hot air at 150 ° C. for 5 minutes to obtain a prepreg. On both surfaces of the obtained prepreg, an electrolytic copper foil “F2-WS-18” having a thickness of 18 μm (manufactured by Furukawa Circuit Foil Co., Ltd., trade name, 10-point average surface roughness Rz = 2.0 to 3.0). Double-sided copper-clad laminates that are metal foil-clad laminates by heating and pressurizing the laminated body so that the adhesive surfaces are combined with the prepreg from both sides at 170 ° C. for 90 minutes under a vacuum pressure of 4.0 MPa. Was made.

<Evaluation of prepreg and double-sided copper-clad laminate>
[Evaluation of flexibility]
Test pieces each having a width of 10 mm and a length of 100 mm were cut out from the prepreg and a wiring board obtained by etching the copper foil of the double-sided copper-clad laminate. A rectangular aluminum plate having a thickness of 5 mm was placed on these test pieces so that the length direction thereof was orthogonal to the length direction of the test pieces. Then, using the edge of the aluminum plate as a fulcrum, the presence or absence of cracks was observed when the test piece was bent upward 90 ° therefrom, and evaluated as follows. The results are shown in Tables 1 and 2.
○: No abnormality
Δ: Whitening due to some cracks
X: Whitening due to cracks on the entire surface.

[Evaluation of solder heat resistance]
A double-sided copper-clad laminate was cut into a 50 mm square to obtain a test piece. The test piece was immersed in a solder bath at 288 ° C., and the time elapsed from that point to the point when the swelling of the test piece was visually observed was measured. The results are shown in Tables 1 and 2.

[Evaluation of adhesion of copper foil to substrate]
The copper foil of the double-sided copper clad laminate was partially etched to form a 1 mm wide copper foil line. Next, the copper foil line was peeled off at a speed of 50 mm / min in the direction of 90 ° with respect to the bonding surface, the load at that time was measured, and the maximum load was peeled off to determine the strength (copper foil adhesiveness). . The results are shown in Tables 1 and 2.

  As is clear from the results shown in Tables 1 and 2, according to the curable resin compositions of Examples 1 to 6, the bending characteristics, heat resistance and the curable resin compositions of Comparative Examples 1 to 3 were compared. It was confirmed that the adhesiveness with the copper foil can be expressed simultaneously.

It is a perspective view which shows one Embodiment of the prepreg by this invention. It is a fragmentary sectional view showing one embodiment of a metal foil tension laminate sheet by the present invention. It is a fragmentary sectional view showing one embodiment of a printed wiring board by the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Metal foil, 11 ... Wiring pattern, 30 ... Board | substrate, 60 ... Metal plating layer, 70 ... Through-hole, 100 ... Pre-preg, 200 ... Metal foil clad laminated board, 300 ... Printed wiring board.

Claims (14)

(A) component: an acrylic polymer having a monomer unit derived from glycidyl (meth) acrylate;
(B) component: an epoxy resin;
(C) component: phenolic resin,
(D) component: a curing accelerator;
(E) component: a thiol compound;
A curable resin composition for printed wiring boards, comprising:   The curable resin composition of Claim 1 in which the said (a) component has the said monomer unit of 1-20 mass% on the basis of the total amount.   The curable resin composition according to claim 1 or 2, wherein the component (a) has a weight average molecular weight of 30000 or more.   The curable resin composition as described in any one of Claims 1-3 whose compounding ratio of the said (a) component is 10 mass% or more on the basis of the total amount of solid content in curable resin composition.   The said (b) component is a curable resin composition as described in any one of Claims 1-4 which has 2 or more of epoxy groups per molecule.   The said (c) component is a curable resin composition as described in any one of Claims 1-5 which has 2 or more of phenolic hydroxyl groups per molecule.   The molar ratio of the phenolic hydroxyl group in the component (c) to the epoxy group in the component (b) (number of moles of phenolic hydroxyl group / number of moles of epoxy group) is 0.5 to 1.5. The curable resin composition as described in any one of Claims 1-6 in which the component c) is mix | blended.   The curable resin composition according to any one of claims 1 to 7, wherein the component (d) is an imidazole compound.   The curable resin composition according to any one of claims 1 to 8, wherein the component (e) is one or more thiol compounds selected from the group consisting of alkylthiols, phenylthiols, and thiol-based coupling agents. object.   The prepreg which has a fiber base material and the curable resin composition as described in any one of Claims 1-9 impregnated in this.   A substrate obtained by heating and pressing the prepreg according to claim 10.   A metal foil-clad laminate comprising the substrate according to claim 11 and a metal foil provided on at least one surface of the substrate.   Metal foil with resin provided with the resin film which consists of a curable resin composition as described in any one of Claims 1-9, and metal foil provided on the at least one surface of the said resin film. A substrate according to claim 11;
A wiring pattern made of metal provided on at least one surface of the substrate;
A printed wiring board comprising:

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