JP5617373B2 - Manufacturing method of prepreg - Google Patents

Description

  The present invention relates to a prepreg manufacturing method and a prepreg obtained by the manufacturing method. More specifically, the present invention relates to a method for producing a prepreg useful for producing a laminate excellent in mechanical strength and peel strength, and a prepreg obtained by this production method.

  As electronic devices become smaller and higher in performance, printed wiring boards used in electronic devices are also required to have higher density and thickness. In order to cope with such high density and thinning, printed wiring boards are required to have improved mechanical strength such as low linear expansion coefficient and high elastic modulus.

For example, in Patent Document 1, an inorganic filler and a thermosetting resin are essential components as a resin composition for forming a printed wiring board with improved mechanical strength, and the average particle diameter is 1. Water having a particle diameter of 0 μm to 5.0 μm, particles having a particle diameter of 0.5 μm or less are 0.2% by mass or less, a BET specific surface area is 1.5 m ² / g or less, and the amount of coarse particles having a particle diameter of 45 μm or more is 20 ppm or less. A resin composition containing aluminum oxide is disclosed. In addition, in this patent document 1, in addition to the aluminum hydroxide whose average particle diameter is 1-5 micrometers as an inorganic filler, the spherical silica whose average particle diameter is 0.4-0.7 micrometers is used, and these, An embodiment is disclosed in which a varnish is obtained by blending a predetermined resin material and a solvent, and a prepreg is obtained by impregnating the obtained varnish into a glass cloth.

JP 2007-146095 A

However, as in Patent Document 1, a varnish containing an inorganic filler having a large particle size (aluminum hydroxide) and an inorganic filler having a small particle size (spherical silica) at the same time as an inorganic filler is used as a glass cloth. When the prepreg obtained by impregnating is laminated with a plurality of the prepregs, or when laminated with other materials to obtain a laminate, the resulting laminate is inferior in peel strength. The inventors have clarified that the mechanical strength is still insufficient to cope with the recent reduction in size and performance of electronic devices.
In particular, the prepreg disclosed in Patent Document 1 has a structure in which an inorganic filler having a small particle size is dispersed in the reinforcing fiber layer and the surface resin layer constituting the prepreg. In addition, a considerable amount of the inorganic filler having a small particle size is contained, and the peel strength is reduced due to the small particle size inorganic filler contained in the surface resin layer, and further, the reinforcing fiber layer. Although a part of the small particle size inorganic filler is dispersed inside, the large particle size inorganic filler is difficult to enter between the single fibers constituting the reinforcing fiber, and as a result, in the reinforcing fiber layer. As a result of studies by the present inventors, it was found that the inorganic filler was not sufficiently impregnated, and the mechanical strength was insufficient.

  An object of this invention is to provide the manufacturing method of a prepreg useful for manufacture of the laminated body excellent in mechanical strength and peel strength, and the prepreg obtained by this manufacturing method. Another object of the present invention is to provide a laminate and a printed wiring board obtained using this prepreg.

  As a result of intensive studies in view of the above problems, the present inventors combined two types of inorganic fillers, an inorganic filler having a large particle size and an inorganic filler having a small particle size, as the inorganic filler to be contained in the prepreg. Among these, a small particle size inorganic filler is localized in the resin-impregnated reinforcing fiber layer, and a large particle size inorganic filler is used as an outer resin constituting both surfaces of the resin-impregnated reinforcing fiber layer. By localizing in the layer, it was found that a prepreg useful for producing a laminate excellent in mechanical strength and peel strength was obtained, and the present invention was completed based on this finding.

That is, according to the present invention,
[1] A step of forming a resin-impregnated reinforcing fiber layer obtained by impregnating reinforcing fibers with a first resin composition containing a first crosslinkable resin and a first inorganic filler; Forming an outer resin layer made of a second resin composition containing a second crosslinkable resin and a second inorganic filler on the surface, the prepreg manufacturing method comprising the first inorganic filler The average particle size of the prepreg is less than the average particle size of the second inorganic filler,
[2] The method for producing a prepreg according to [1], wherein the first crosslinkable resin and / or the second crosslinkable resin is a cycloolefin polymer.
[3] The resin-impregnated reinforcing fiber layer is formed by impregnating the reinforcing fiber with a first polymerizable composition containing a cycloolefin monomer, a metathesis polymerization catalyst, and the first inorganic filler, and performing bulk polymerization. The method for producing a prepreg according to the above [2], characterized by:
[4] The above-mentioned [2], wherein the outer resin layer is formed by bulk polymerization of a second polymerizable composition containing a cycloolefin monomer, a metathesis polymerization catalyst, and the second inorganic filler. Or the method for producing the prepreg according to [3],
[5] The average particle size of the first inorganic filler is less than 1 μm, and the average particle size of the second inorganic filler is 1 μm or more and less than 5 μm. A method for producing the prepreg according to any one of the above ,
Is provided.

  According to the present invention, a method for producing a prepreg useful for producing a laminate excellent in mechanical strength and peel strength, a prepreg obtained by this production method, and a laminate and a printed wiring obtained using this prepreg A board is provided. Since the laminate and the printed wiring board of the present invention are excellent in mechanical strength and peel strength, they can be suitably used for substrates of various electronic devices.

  The method for producing a prepreg of the present invention includes a step of forming a resin-impregnated reinforcing fiber layer obtained by impregnating reinforcing fibers with a first resin composition containing a first crosslinkable resin and a first inorganic filler; Forming an outer resin layer comprising a second resin composition containing a second crosslinkable resin and a second inorganic filler on both surfaces of the impregnated reinforcing fiber layer, and a method for producing a prepreg comprising: The average particle diameter of the first inorganic filler is less than the average particle diameter of the second inorganic filler.

(Resin impregnated reinforcing fiber layer)
First, the resin-impregnated reinforcing fiber layer formed by the production method of the present invention will be described. In the present invention, the resin-impregnated reinforcing fiber layer is a layer formed by impregnating reinforcing fibers with the first resin composition containing the first crosslinkable resin and the first inorganic filler.

  The first crosslinkable resin contained in the first resin composition is not particularly limited as long as it is a resin having a crosslinkable functional group or a crosslinkable carbon-carbon unsaturated bond. Examples of the resin include a cycloolefin polymer, an epoxy resin, a phenol resin, a polyimide resin, a triazine resin, a melamine resin, a modified resin obtained by modifying these, and these may be used alone or 2 It can be used in combination of more than one species. Among these, from the viewpoint that the obtained laminated body can have a small dielectric loss tangent, and thereby, when the laminated body is applied to a circuit board, transmission loss at high frequencies can be reduced. A cycloolefin polymer is preferable, and as such a cycloolefin polymer, it is more preferable to use a polymer obtained by ring-opening polymerization of a cycloolefin monomer by a known method. Examples of the crosslinkable functional group include an epoxy group, a hydroxyl group, an isocyanate group, and a sulfonic acid group. The crosslinkable carbon-carbon unsaturated bond will be described later.

  Although it does not specifically limit as a 1st inorganic filler contained in a 1st resin composition, What has an average particle diameter less than the average particle diameter of the 2nd inorganic filler contained in the outer side resin layer mentioned later. There is no particular limitation. By including the first inorganic filler in the resin-impregnated reinforcing fiber layer, the resulting laminate can have a low coefficient of linear expansion and a high elastic modulus, thereby improving mechanical strength. It becomes possible.

  Examples of the first inorganic filler include hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; oxides such as silicon oxide (silica), aluminum oxide, magnesium oxide, zinc oxide, and titanium oxide; sodium chloride, Chlorides such as calcium chloride; sulfates such as sodium hydrogen sulfate and sodium sulfate; nitrates such as sodium nitrate and calcium nitrate; phosphates such as sodium dihydrogen phosphate and sodium hydrogen phosphate; mica, kaolin, fly ash, Silicates such as talc and mica; titanates such as barium titanate, strontium titanate and calcium titanate; carbonates such as sodium carbonate and calcium carbonate; carbides such as silicon carbide and boron carbide; aluminum nitride and boron nitride , Nitrides such as silicon nitride; glass powder Carbon black; metal particles such as aluminum, nickel, magnesium, copper, zinc, and iron; ferrites such as Mn—Mg—Zn, Ni—Zn, and Mn—Zn; carbonyl iron, iron-silicon alloys, iron— Examples thereof include ferromagnetic metal powders such as aluminum-silicon alloys and iron-nickel alloys.

  Of these, hydroxides, oxides, titanates and carbonates are preferred, aluminum hydroxide and magnesium hydroxide for hydroxides, silicon oxide (silica) for oxides, barium titanate for titanates, Of strontium titanate, calcium titanate, and carbonates, calcium carbonate is more preferred. These fillers can be used alone or in combination of two or more.

  In addition, what was surface-treated with the well-known silane coupling agent, titanate coupling agent, aluminum coupling agent, etc. can also be used for these fillers.

  The average particle size of the first inorganic filler may be less than the average particle size of the second inorganic filler contained in the outer resin layer described later, but is preferably less than 1 μm, more preferably 0.3 μm. It is not less than 1 μm, more preferably not less than 0.5 μm and less than 1 μm. When the average particle diameter of the first inorganic filler is too large, it becomes difficult to enter between the single fibers constituting the reinforcing fibers, and it becomes difficult to obtain the effect of improving the mechanical strength. In addition, the average particle diameter of a 1st inorganic filler is an average value of the length of a longitudinal direction and a transversal direction when each particle | grains which comprise a 1st inorganic filler are seen three-dimensionally.

  In 100% by volume of the first resin composition, the content of the first inorganic filler is usually 10 to 45% by volume, preferably 15 to 40% by volume, and more preferably 20 to 35% by volume. If the content of the first inorganic filler is too small, and if the content is too large, the dispersibility of the first inorganic filler in the reinforcing fibers is lowered, so that the first inorganic filler sufficiently enters the reinforcing fibers. Therefore, it is difficult to obtain an effect of improving the mechanical strength in the obtained laminate. In the prepreg obtained by the method for producing a prepreg of the present invention, the first inorganic filler is generally localized around the reinforcing fibers of the resin-impregnated reinforcing fiber layer.

  As the reinforcing fibers, inorganic and / or organic fibers can be used, for example, organic fibers such as PET (polyethylene terephthalate) fibers, aramid fibers, ultra-high molecular polyethylene fibers, polyamide (nylon) fibers, and liquid crystal polyester fibers. And inorganic fibers such as glass fibers, carbon fibers, alumina fibers, tungsten fibers, molybdenum fibers, budene fibers, titanium fibers, steel fibers, boron fibers, silicon carbide fibers, and silica fibers. Among these, organic fibers and glass fibers are preferable, and aramid fibers, liquid crystal polyester fibers, and glass fibers are particularly preferable. As the glass fiber, fibers such as E glass, NE glass, S glass, D glass, H glass, and T glass can be suitably used. These can be used individually by 1 type or in combination of 2 or more types. The shape of the fibrous reinforcing material is not particularly limited, and examples thereof include mats, cloths, and nonwoven fabrics.

  The content ratio of the reinforcing fiber in the obtained prepreg is usually in the range of 5 to 70% by volume, preferably 10 to 60% by volume, more preferably 15 to 50% by volume in 100% by volume of the prepreg. Within this range, the dielectric properties and mechanical strength of the resulting laminate are balanced, which is preferable.

  Further, in the present invention, when the first crosslinkable resin constituting the first resin composition is a cycloolefin polymer, the resin-impregnated reinforcing fiber layer is replaced with a cycloolefin monomer, a metathesis polymerization catalyst, and the above-described first. It is preferable to form the first polymerizable composition containing one inorganic filler by impregnating the above-described reinforcing fiber and performing bulk polymerization.

  The cycloolefin monomer constituting the first polymerizable composition has an alicyclic structure formed of carbon atoms, and a compound having one ring-opening polymerizable carbon-carbon double bond in the alicyclic structure It is.

Examples of the alicyclic structure of the cycloolefin monomer include monocycles, polycycles, condensed polycycles, bridged rings, and combination polycycles thereof. Although there is no limitation in particular in carbon number which comprises each alicyclic structure, Usually, 4-30 pieces, Preferably it is 5-20 pieces, More preferably, it is 5-15 pieces.
The cycloolefin monomer has a hydrocarbon group having 1 to 30 carbon atoms such as an alkyl group, an alkenyl group, an alkylidene group, and an aryl group, and a polar group such as a carboxyl group or an acid anhydride group as a substituent. However, from the viewpoint of making the obtained laminate a low dielectric loss tangent, those having no polar group, that is, comprising only carbon atoms and hydrogen atoms are preferable.

  As the cycloolefin monomer, either a monocyclic cycloolefin monomer or a polycyclic cycloolefin monomer can be used. From the viewpoint of highly balancing the dielectric properties and heat resistance properties of the resulting laminate, polycyclic cycloolefin monomers are preferred. As the polycyclic cycloolefin monomer, a norbornene-based monomer is particularly preferable. The “norbornene monomer” refers to a cycloolefin monomer having a norbornene ring structure in the molecule. Examples include norbornenes, dicyclopentadiene, and tetracyclododecene.

As the cycloolefin monomer, any of those having no crosslinkable carbon-carbon unsaturated bond and those having one or more crosslinkable carbon-carbon unsaturated bonds can be used. As used herein, “crosslinkable carbon-carbon unsaturated bond” refers to a carbon-carbon unsaturated bond that does not participate in ring-opening polymerization and can participate in a crosslinking reaction. The cross-linking reaction is a reaction that forms a bridge structure, and there are various forms such as a condensation reaction, an addition reaction, a radical reaction, and a metathesis reaction. It refers to a crosslinking reaction, particularly a radical crosslinking reaction. Examples of the crosslinkable carbon-carbon unsaturated bond include carbon-carbon unsaturated bonds other than aromatic carbon-carbon unsaturated bonds, that is, aliphatic carbon-carbon double bonds or triple bonds. Usually refers to an aliphatic carbon-carbon double bond. In the cycloolefin monomer having one or more crosslinkable carbon-carbon unsaturated bonds, the position of the unsaturated bond is not particularly limited, and in addition to the alicyclic structure formed by carbon atoms, other than the alicyclic structure It may be present at any position of, for example, at the end or inside of the side chain. For example, the aliphatic carbon-carbon double bond may exist as a vinyl group (CH ₂ ═CH—), a vinylidene group (CH ₂ ═C <), or a vinylene group (—CH═CH—). Since it exhibits radical crosslinkability, it preferably exists as a vinyl group and / or vinylidene group, and more preferably as a vinylidene group.

  Examples of cycloolefin monomers having no crosslinkable carbon-carbon unsaturated bond include cyclopentene, 3-methylcyclopentene, 4-methylcyclopentene, 3,4-dimethylcyclopentene, 3,5-dimethylcyclopentene, and 3-chlorocyclopentene. Monocyclic cycloolefin monomers such as cyclohexene, 3-methylcyclohexene, 4-methylcyclohexene, 3,4-dimethylcyclohexene, 3-chlorocyclohexene, and cycloheptene; norbornene, 5-methyl-2-norbornene, 5-ethyl-2-norbornene, 5-propyl-2-norbornene, 5,6-dimethyl-2-norbornene, 1-methyl-2-norbornene, 7-methyl-2-norbornene, 5,5,6-trimethyl- 2-norbornene, 5- Enyl-2-norbornene, tetracyclododecene, 1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene (TCD), 2-methyl-1, 4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-ethyl-1,4,5,8-dimethano-1,2,3,4 4a, 5,8,8a-octahydronaphthalene, 2,3-dimethyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2- Hexyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-ethylidene-1,4,5,8-dimethano-1,2, 3,4,4a, 5,8,8a-octahydronaphthalene, 2-fluoro-1, , 5,8-Dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 1,5-dimethyl-1,4,5,8-dimethano-1,2,3,4 , 4a, 5,8,8a-octahydronaphthalene, 2-cyclohexyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2, , 3-Dichloro-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-isobutyl-1,4,5,8-dimethano-1 , 2,3,4,4a, 5,8,8a-octahydronaphthalene, 1,2-dihydrodicyclopentadiene, 5-chloro-2-norbornene, 5,5-dichloro-2-norbornene, 5-fluoro- 2-norbornene, 5,5,6-trifluoro-6-tri Fluoromethyl-2-norbornene, 5-chloromethyl-2-norbornene, 5-methoxy-2-norbornene, 5,6-dicarboxyl-2-norbornene anhydrate, 5-dimethylamino-2-norbornene, and 5- Norbornene monomers such as cyano-2-norbornene; and norbornene monomers having no crosslinkable carbon-carbon unsaturated bond are preferable.

Examples of the cycloolefin monomer having one or more crosslinkable carbon-carbon unsaturated bonds include 3-vinylcyclohexene, 4-vinylcyclohexene, 1,3-cyclopentadiene, 1,3-cyclohexadiene, 1,4- Monocyclic cycloolefin monomers such as cyclohexadiene, 5-ethyl-1,3-cyclohexadiene, 1,3-cycloheptadiene, and 1,3-cyclooctadiene; 5-ethylidene-2-norbornene, 5- Methylidene-2-norbornene, 5-isopropylidene-2-norbornene, 5-vinyl-2-norbornene, 5-allyl-2-norbornene, 5,6-diethylidene-2-norbornene, dicyclopentadiene, and 2,5- Norbornene-based monomers such as norbornadiene; Ku crosslinkable carbon - is a norbornene-based monomer having one or more carbon unsaturated bond.
These cycloolefin monomers can be used alone or in combination of two or more.

The cycloolefin monomer used in the present invention preferably includes a cycloolefin monomer having one or more crosslinkable carbon-carbon unsaturated bonds. When such a cycloolefin monomer is used, reliability such as crack resistance is improved in the obtained laminate, which is preferable.
In the cycloolefin monomer for forming the cycloolefin polymer, the blending ratio of the cycloolefin monomer having one or more crosslinkable carbon-carbon unsaturated bonds and the cycloolefin monomer having no crosslinkable carbon-carbon unsaturated bonds is The weight ratio (cycloolefin monomer having at least one crosslinkable carbon-carbon unsaturated bond / cycloolefin monomer having no crosslinkable carbon-carbon unsaturated bond) is usually 5 / 95 to 100/0, preferably 10/90 to 90/10, more preferably 15/85 to 70/30. If the said mixture ratio exists in this range, in the obtained laminated body, characteristics, such as heat resistance and crack resistance, can be improved highly, and it is suitable.

  In addition, the 1st polymerizable composition may contain the arbitrary monomers copolymerizable with the cycloolefin monomer mentioned above, as long as expression of the effect of this invention is not inhibited.

  As the metathesis polymerization catalyst constituting the first polymerizable composition, the above-mentioned cycloolefin monomer can be subjected to metathesis ring-opening polymerization, usually a plurality of ions, atoms, polyatomic ions, and compounds with a transition metal atom as a central atom And a complex formed by bonding such as. As transition metal atoms, atoms of Group 5, Group 6, and Group 8 (according to the long-period periodic table; the same applies hereinafter) are used. Although the atoms of each group are not particularly limited, examples of the Group 5 atom include tantalum, examples of the Group 6 atom include molybdenum and tungsten, and examples of the Group 8 atom include: Examples include ruthenium and osmium. Of the transition metal atoms, Group 8 ruthenium and osmium are preferred. That is, the metathesis polymerization catalyst used in the present invention is preferably a complex having ruthenium or osmium as a central atom, and more preferably a complex having ruthenium as a central atom. As the complex having ruthenium as a central atom, a ruthenium carbene complex in which a carbene compound is coordinated to ruthenium is preferable. Here, the “carbene compound” is a general term for compounds having a methylene free group, and refers to a compound having an uncharged divalent carbon atom (carbene carbon) as represented by (> C :). Since the ruthenium carbene complex is excellent in catalytic activity during bulk polymerization, when the first polymerizable composition is bulk polymerized, there is little odor derived from unreacted monomers, and a high-quality molded product with good productivity can be obtained. Can do. In addition, it is relatively stable to oxygen and moisture in the air and is not easily deactivated, so that it can be used even in the atmosphere.

  Specific examples of the ruthenium carbene complex include complexes represented by the following general formula (1) or (2).

In the general formulas (1) and (2), R ¹ and R ² may each independently contain a hydrogen atom, a halogen atom, or a halogen atom, oxygen atom, nitrogen atom, sulfur atom, phosphorus atom, or silicon atom. It represents a good cyclic or chain hydrocarbon group having 1 to 20 carbon atoms. X ¹ and X ² each independently represent an arbitrary anionic ligand. L ¹ and L ² each independently represent a hetero atom-containing carbene compound or a neutral electron donating compound other than the hetero atom-containing carbene compound. R ¹ and R ² may be bonded to each other to form an aliphatic ring or an aromatic ring that may contain a hetero atom. Furthermore, R ¹ , R ² , X ¹ , X ² , L ¹ and L ² may be bonded together in any combination to form a multidentate chelating ligand.

  A heteroatom means an atom of groups 15 and 16 of the periodic table, and specifically, a nitrogen atom (N), an oxygen atom (O), a phosphorus atom (P), a sulfur atom (S), an arsenic atom (As), selenium atom (Se), and the like. Among these, N, O, P, and S are preferable from the viewpoint of obtaining a stable carbene compound, and N is particularly preferable.

  As the ruthenium carbene complex, since the mechanical strength and impact resistance of the obtained prepreg and laminate can be highly balanced, a carbene compound having a heterocyclic structure as a hetero atom-containing carbene compound is used as a ligand. Are preferably included. As the heterocyclic structure, an imidazoline ring structure or an imidazolidine ring structure is preferable.

  Examples of the carbene compound having a heterocyclic structure include compounds represented by the following general formula (3) or (4).

In the general formula (3) or (4), R ^{3 to} R ⁶ each independently include a hydrogen atom; a halogen atom; or a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or a silicon atom. Represents a good cyclic or chain hydrocarbon group having 1 to 20 carbon atoms. R ^{3 to} R ⁶ may be bonded to each other in any combination to form a ring.

  Examples of the compound represented by the general formula (3) or (4) include 1,3-dimesitylimidazolidin-2-ylidene, 1,3-di (1-adamantyl) imidazolidin-2-ylidene, 1 , 3-dicyclohexylimidazolidine-2-ylidene, 1,3-dimesityloctahydrobenzimidazol-2-ylidene, 1,3-diisopropyl-4-imidazoline-2-ylidene, 1,3-di (1-phenyl) Ethyl) -4-imidazoline-2-ylidene, 1,3-dimesityl-2,3-dihydrobenzimidazol-2-ylidene and the like.

  In addition to the compound represented by the general formula (3) or (4), 1,3,4-triphenyl-2,3,4,5-tetrahydro-1H-1,2,4-triazole-5 -Iridene, 1,3-dicyclohexylhexahydropyrimidin-2-ylidene, N, N, N ', N'-tetraisopropylformamidinylidene, 1,3,4-triphenyl-4,5-dihydro-1H- Hetero atom-containing carbene compounds such as 1,2,4-triazole-5-ylidene and 3- (2,6-diisopropylphenyl) -2,3-dihydrothiazol-2-ylidene can also be used.

In the general formulas (1) and (2), the anionic (anionic) ligands X ¹ and X ² are ligands having a negative charge when separated from the central metal atom. For example, halogen atoms such as fluorine atom (F), chlorine atom (Cl), bromine atom (Br), and iodine atom (I), diketonate group, substituted cyclopentadienyl group, alkoxy group, aryloxy group, and carboxyl Examples include groups. Among these, a halogen atom is preferable and a chlorine atom is more preferable.

  The neutral electron-donating compound may be any ligand as long as it has a neutral charge when it is separated from the central metal. Specific examples thereof include carbonyls, amines, pyridines, ethers, nitriles, esters, phosphines, thioethers, aromatic compounds, olefins, isocyanides, thiocyanates, and the like. Among these, phosphines, ethers and pyridines are preferable, and trialkylphosphine is more preferable.

  Examples of the complex compound represented by the general formula (1) include benzylidene (1,3-dimesityl-4-imidazolidine-2-ylidene) (tricyclohexylphosphine) ruthenium dichloride, benzylidene (1,3-dimesityl-4, 5-dibromo-4-imidazoline-2-ylidene) (tricyclohexylphosphine) ruthenium dichloride, (1,3-dimesityl-4-imidazoline-2-ylidene) (3-phenyl-1H-indene-1-ylidene) (tri Cyclohexylphosphine) ruthenium dichloride, (1,3-dimesitylimidazolidine-2-ylidene) (3-methyl-2-buten-1-ylidene) (tricyclopentylphosphine) ruthenium dichloride, benzylidene (1,3-dimesityl- Octahydrobenzimidazo -2-ylidene) (tricyclohexylphosphine) ruthenium dichloride, benzylidene [1,3-di (1-phenylethyl) -4-imidazoline-2-ylidene] (tricyclohexylphosphine) ruthenium dichloride, benzylidene (1,3-dimesityl) -2,3-dihydrobenzimidazol-2-ylidene) (tricyclohexylphosphine) ruthenium dichloride, benzylidene (tricyclohexylphosphine) (1,3,4-triphenyl-2,3,4,5-tetrahydro-1H-1 , 2,4-triazole-5-ylidene) ruthenium dichloride, (1,3-diisopropylhexahydropyrimidin-2-ylidene) (ethoxymethylene) (tricyclohexylphosphine) ruthenium dichloride, benzylidene (1 3-Dimesitylimidazolidin-2-ylidene) pyridine ruthenium dichloride, (1,3-Dimesitylimidazolidine-2-ylidene) (2-phenylethylidene) (tricyclohexylphosphine) ruthenium dichloride, (1,3- Dimesityl-4-imidazoline-2-ylidene) (2-phenylethylidene) (tricyclohexylphosphine) ruthenium dichloride, (1,3-dimesityl-4,5-dibromo-4-imidazoline-2-ylidene) [(phenylthio) methylene ] (Tricyclohexylphosphine) ruthenium dichloride, (1,3-dimesityl-4,5-dibromo-4-imidazoline-2-ylidene) (2-pyrrolidone-1-ylmethylene) (tricyclohexylphosphine) ruthenium dichloride, etc. A ruthenium complex compound in which one atom-containing carbene compound and one neutral electron-donating compound are bonded;

  Ruthenium compounds in which two neutral electron-donating compounds are bound, such as benzylidenebis (tricyclohexylphosphine) ruthenium dichloride, (3-methyl-2-buten-1-ylidene) bis (tricyclopentylphosphine) ruthenium dichloride;

  Two heteroatom-containing carbene compounds such as benzylidenebis (1,3-dicyclohexylimidazolidine-2-ylidene) ruthenium dichloride and benzylidenebis (1,3-diisopropyl-4-imidazoline-2-ylidene) ruthenium dichloride bonded Ruthenium complex compounds; and the like.

  Examples of the complex compound represented by the general formula (2) include (1,3-dimesityrylimidazolidine-2-ylidene) (phenylvinylidene) (tricyclohexylphosphine) ruthenium dichloride, (t-butylvinylidene) (1 , 3-diisopropyl-4-imidazoline-2-ylidene) (tricyclopentylphosphine) ruthenium dichloride, bis (1,3-dicyclohexyl-4-imidazoline-2-ylidene) phenylvinylidene ruthenium dichloride, and the like.

  Among these complex compounds, those having one compound represented by the general formula (1) and represented by the general formula (4) as a ligand are most preferable.

  These ruthenium carbene complexes can be produced by the methods described in Org. Lett., 1999, Vol. 1, page 953, Tetrahedron. Lett., 1999, Vol. 40, page 2247, and the like.

  The metathesis polymerization catalysts can be used alone or in combination of two or more. The amount of the metathesis polymerization catalyst used is a molar ratio (metal atom in the metathesis polymerization catalyst: cycloolefin monomer) and is usually from 1: 2,000 to 1: 2,000,000, preferably from 1: 5,000 to 1. : 1,000,000, more preferably in the range of 1: 10,000 to 1: 500,000.

  If desired, the metathesis polymerization catalyst can be used dissolved or suspended in a small amount of an inert solvent. Such solvents include chain aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, liquid paraffin, and mineral spirits; cyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, and ethylcyclohexane. , Cyclohexane, decahydronaphthalene, dicycloheptane, tricyclodecane, hexahydroindene, cyclooctane and other alicyclic hydrocarbons; benzene, toluene, xylene and other aromatic hydrocarbons; indene, tetrahydronaphthalene, etc. Hydrocarbons having an alicyclic ring and an aromatic ring; nitrogen-containing hydrocarbons such as nitromethane, nitrobenzene, and acetonitrile; oxygen-containing hydrocarbons such as diethyl ether and tetrahydrofuran; . Among these, it is preferable to use a chain aliphatic hydrocarbon, an alicyclic hydrocarbon, an aromatic hydrocarbon, and a hydrocarbon having an alicyclic ring and an aromatic ring.

  In addition, the 1st polymeric composition used by this invention can be obtained by mixing the said component. As a mixing method, a conventional method may be followed. For example, a liquid (catalyst liquid) in which a metathesis polymerization catalyst is dissolved or dispersed in an appropriate solvent is prepared, and a cycloolefin monomer is added separately as needed. It can be prepared by preparing a liquid (monomer liquid) containing an agent (other compounding agents will be described later) and the like, adding the catalyst liquid to the monomer liquid, and stirring.

(Outside resin layer)
Next, the outer resin layer formed by the manufacturing method of the present invention will be described. In this invention, an outer side resin layer is a layer which consists of a 2nd resin composition containing the 2nd crosslinkable resin and 2nd inorganic filler which are formed on both surfaces of the resin impregnation reinforcement | strengthening fiber layer mentioned above.

  The second crosslinkable resin contained in the second resin composition is not particularly limited as long as it is a resin having a crosslinkable functional group or a crosslinkable carbon-carbon unsaturated bond. Similarly to the functional resin, cycloolefin polymer, epoxy resin, phenol resin, polyimide resin, triazine resin, melamine resin, modified resin obtained by modifying these, and the like can be used. These can be used alone or in combination of two or more. Of these, cycloolefin polymers are preferred. Note that the second crosslinkable resin and the first crosslinkable resin may be the same or different from each other.

  Further, the second inorganic filler contained in the second resin composition is not particularly limited, but has an average particle diameter exceeding the average particle diameter of the first inorganic filler contained in the resin-impregnated reinforcing fiber layer described above. It is not particularly limited as long as it has, and the same material as the first inorganic filler described above can be used except that the average particle diameter exceeds the average particle diameter of the first inorganic filler. By containing the second inorganic filler in the outer resin layer, it is possible to improve the resin fluidity on the surface of the obtained prepreg and to improve the peel strength of the obtained laminate. Note that the second inorganic filler and the first inorganic filler may be made of the same material, or may be made of different materials.

  The average particle size of the second inorganic filler may be larger than the average particle size of the second inorganic filler contained in the above-described resin-impregnated reinforcing fiber layer, but is preferably 1 μm or more and less than 5 μm. Preferably it is 1-4 micrometers, More preferably, it is 1-3 micrometers. If the average particle size of the second inorganic filler is too small, it is difficult to improve the peel strength in the resulting laminate. On the other hand, if it is too large, the coefficient of linear expansion tends not to be sufficiently reduced. The average particle diameter of the second inorganic filler is an average value of the lengths in the longitudinal direction and the short direction when each particle constituting the second inorganic filler is viewed three-dimensionally.

  In 100% by volume of the second resin composition, the content of the second inorganic filler is usually 20 to 80% by volume, preferably 25 to 70% by volume, and more preferably 30 to 60% by volume. When there is too little content of a 2nd inorganic filler, it will become difficult to acquire the improvement effect of mechanical strength in the laminated body obtained. On the other hand, if the amount is too large, the peel strength may decrease. In the prepreg obtained by the prepreg manufacturing method of the present invention, the second inorganic filler is generally localized in the outer resin layer.

  The second resin composition constituting the outer resin layer is the same as the above-described first inorganic filler, for example, a filler other than the above-mentioned second inorganic filler, as long as the effects of the present invention are not impaired. An inorganic filler having an average particle diameter may be contained.

  Further, in the present invention, when the second crosslinkable resin constituting the second resin composition is a cycloolefin polymer, the outer resin layer is formed of a cycloolefin monomer, a metathesis polymerization catalyst, and the above-described second inorganic resin. It is preferable to form the second polymerizable composition containing the filler by bulk polymerization on both surfaces of the above-described resin-impregnated reinforcing fiber layer.

  As a cycloolefin monomer which comprises a 2nd polymeric composition, the thing similar to the 1st polymeric composition mentioned above can be used. Moreover, the arbitrary monomer which can be copolymerized with a cycloolefin monomer may be contained similarly to the 1st polymeric composition mentioned above. The cycloolefin monomer constituting the second polymerizable composition and the cycloolefin monomer constituting the first polymerizable composition may be the same or different from each other.

  As the metathesis polymerization catalyst constituting the second polymerizable composition, the same one as the first polymerizable composition described above can be used, and the blending amount is the same as the first polymerizable composition described above. Good.

  The second polysynthetic composition used in the present invention can be prepared in the same manner as the first polymerizable composition described above.

(Other ingredients)
The first resin composition for forming the resin impregnated reinforcing fiber layer and the second resin composition for forming the outer resin layer described above contain a crosslinking agent, a reactive fluidizing agent, or a crosslinking aid, as desired. You may do it. As described above, when the resin-impregnated reinforcing fiber layer is formed using the first polymerizable composition, or when the outer resin layer is formed using the second polymerizable composition, these What is necessary is just to contain a crosslinking agent, a reactive fluidizing agent, or a crosslinking adjuvant in the 1st polymeric composition and the 2nd polymeric composition, respectively.

  The crosslinking agent is used for the purpose of crosslinking reaction of the first crosslinkable resin forming the resin-impregnated reinforcing fiber layer and / or the second crosslinkable resin forming the outer resin layer. By containing a cross-linking agent, the first cross-linkable resin and / or the second cross-linkable resin can be effectively post-cross-linked. Here, “after-crosslinking is possible” means that, when heated, the crosslinking reaction proceeds to become a crosslinked resin. In this case, the prepreg obtained by the present invention uses the first crosslinkable resin and the second crosslinkable resin as a matrix resin, has high viscosity even when melted by heating, and maintains its shape, while holding any member. When brought into contact, the surface exhibits followability to the shape of the member, and finally crosslinks and cures. Such characteristics of the prepreg of the present invention are considered to contribute to improvement of wiring embedding property and interlayer adhesion in a laminate obtained by laminating, melting and crosslinking by heating.

  Although it does not specifically limit as said crosslinking agent, Usually, a radical generator is used suitably. Examples of the radical generator include organic peroxides, diazo compounds, and nonpolar radical generators, and organic peroxides and nonpolar radical generators are preferable.

  Examples of the organic peroxide include hydroperoxides such as t-butyl hydroperoxide, p-menthane hydroperoxide, and cumene hydroperoxide; dicumyl peroxide, t-butylcumyl peroxide, α, α′-bis (t -Butylperoxy-m-isopropyl) benzene, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) -3-hexyne, and 2,5-dimethyl-2,5- Dialkyl peroxides such as di (t-butylperoxy) hexane; diacyl peroxides such as dipropionyl peroxide and benzoyl peroxide; 2,2-di (t-butylperoxy) butane, 1,1-di (t-hexylperoxy) Cyclohexane, 1,1-di (t-butylperoxy)- Peroxyketals such as 2-methylcyclohexane and 1,1-di (t-butylperoxy) cyclohexane; peroxyesters such as t-butylperoxyacetate and t-butylperoxybenzoate; t-butylperoxyisopropylcarbonate and di Peroxycarbonates such as (isopropylperoxy) dicarbonate; alkylsilyl peroxides such as t-butyltrimethylsilyl peroxide; 3,3,5,7,7-pentamethyl-1,2,4-trioxepane, 3,6,9- Cyclic peroxides such as triethyl-3,6,9-trimethyl-1,4,7-triperoxonan and 3,6-diethyl-3,6-dimethyl-1,2,4,5-tetroxane; Is mentioned. Among these, dialkyl peroxides, peroxyketals, and cyclic peroxides are preferable in that there are few obstacles to the polymerization reaction.

  Examples of the diazo compound include 4,4'-bisazidobenzal (4-methyl) cyclohexanone and 2,6-bis (4'-azidobenzal) cyclohexanone.

  Nonpolar radical generators include 2,3-dimethyl-2,3-diphenylbutane, 3,4-dimethyl-3,4-diphenylhexane, 1,1,2-triphenylethane, and 1,1,1 -Triphenyl-2-phenylethane and the like.

  When a radical generator is used as a crosslinking agent, the 1 minute half-life temperature is appropriately selected depending on the conditions of curing (crosslinking of the prepreg), but is usually 100 to 300 ° C, preferably 150 to 250 ° C, more preferably. It is the range of 160-230 degreeC. Here, the half-life temperature for 1 minute is a temperature at which half of the radical generator decomposes in 1 minute. The 1-minute half-life temperature of the radical generator may be referred to, for example, a catalog or homepage of each radical generator manufacturer (for example, Nippon Oil & Fats Co., Ltd.).

  The above radical generators can be used alone or in combination of two or more. As a compounding quantity of a radical generating agent, it is 0.01-10 weight part normally with respect to 100 weight part of 1st crosslinkable resin or 2nd crosslinkable resin, Preferably it is 0.1-10 weight part, More preferably The range is 0.5 to 5 parts by weight.

  The reactive fluidizing agent is present in a substantially free state in the first crosslinkable resin and / or the second crosslinkable resin, whereby the first crosslinkable resin and / or the second crosslinker is used as the fluidizing agent. When the prepreg of the present invention is heated and melted by lowering the glass transition temperature (Tg) of the functional resin to increase the fluidity of the first crosslinkable resin and / or the second crosslinkable resin during heating and melting, While the followability to the shape of an arbitrary member brought into contact with the surface is improved, when the first crosslinkable resin and / or the second crosslinkable resin is subjected to a crosslink reaction, the first crosslink is involved in the crosslink reaction. It is a monofunctional compound showing binding reactivity to the functional resin and / or the second crosslinkable resin. Since the reactive fluidizing agent has such properties, it is preferably contained in the second resin composition constituting the outer resin layer of the prepreg.

  By using such a reactive fluidizing agent, when the prepreg obtained by the present invention is laminated with a circuit board or the like, it can be easily melt-laminated by heating, and the resulting laminate can be adhered to the interlayer. In addition, the wiring embedding property can be improved. Further, the reactive fluidizing agent has a binding reactivity to the first crosslinkable resin and / or the second crosslinkable resin when the first crosslinkable resin and / or the second crosslinkable resin is subjected to a crosslink reaction by heating. Therefore, as the crosslinking reaction proceeds, the number of free ones in the first crosslinkable resin and / or the second crosslinkable resin decreases, and at the end of the crosslinking reaction, the free state is substantially free. It is presumed that nothing exists. Therefore, unlike the so-called plasticizer, it does not become a factor for reducing the heat resistance of the obtained laminate, but rather, the obtained laminate can have the effect of further improving the heat resistance and crack resistance.

  As such a reactive fluidizing agent, for example, there is no polymerizable carbon-carbon unsaturated bond (carbon-carbon double bond or triple bond), and the first crosslinkable resin and / or the second crosslinkable is used. Examples thereof include a monofunctional compound having one group exhibiting a binding reactivity to the first crosslinkable resin and / or the second crosslinkable resin in relation to the resin crosslinking reaction. Examples of the polymerizable carbon-carbon unsaturated bond include a polymerizable carbon-carbon double bond and an aliphatic carbon-carbon unsaturated bond group that can participate in ring-opening polymerization such as a vinyl group. . Examples of the group that participates in the crosslinking reaction and exhibits the binding reactivity to the first crosslinking resin and / or the second crosslinking resin include, for example, a crosslinking carbon-carbon unsaturated bond, or an organic group that exhibits the binding reactivity. Is mentioned. Among these, since it is excellent in the binding reactivity to the first crosslinkable resin and / or the second crosslinkable resin, the reactive fluidizing agent does not have a polymerizable carbon-carbon unsaturated bond, and Monofunctional compounds having one crosslinkable carbon-carbon unsaturated bond are preferred. The crosslinkable carbon-carbon unsaturated bond contained in the compound constituting the reactive fluidizing agent is preferably present, for example, as a vinylidene group present at the molecular end, particularly as an isopropenyl group or methacryl group. More preferably, it is present as a methacrylic group. Moreover, as an organic group which shows the said binding reactivity, an epoxy group, a hydroxyl group, an isocyanate group, a sulfonic acid group etc. are mentioned, for example.

  As the reactive fluidizing agent in the present invention, the cyclic hydrocarbon group-containing methacrylate compound represented by the following general formula (5) is particularly excellent in the binding reactivity to the first crosslinkable resin and / or the second crosslinkable resin. Is particularly preferred.

In the general formula (5), R ⁷ represents a substituted or unsubstituted saturated alicyclic group having 3 to 30 carbon atoms or a substituted or unsubstituted aromatic group having 6 to 30 carbon atoms, and n is 0. It is an integer of -10.
Examples of the saturated alicyclic group having 3 to 30 carbon atoms include monocyclic groups such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group; bicyclic groups such as a bicyclohexyl group; and tricyclo [5. 2.1.0 ^2,6 ] Decanyl group (also referred to as dicyclopentanyl group) and the like; and tetracyclic groups such as adamantyl group; and the like. The saturated alicyclic group is preferably a tricyclic group or a tetracyclic group from the viewpoint of improving the heat resistance of the resulting laminate, and is a tricyclo [5.2.1.0 ^2,6 ] decanyl group or an adamantyl group. The group is more preferable, and a tricyclo [5.2.1.0 ^2,6 ] decanyl group is particularly preferable.
Examples of the aromatic group having 6 to 30 carbon atoms include monocyclic groups such as phenyl groups; bicyclic groups such as naphthyl groups and biphenyl groups; tricyclic groups such as fluorenyl groups; and the like. As the aromatic group, from the same viewpoint as the saturated alicyclic group, a monocyclic group is preferable, and a phenyl group is more preferable.
Examples of the substituent for the saturated alicyclic group and aromatic group include polar groups such as an alkyl group having 3 to 11 carbon atoms, an alkoxy group having 3 to 11 carbon atoms, a carboxyl group, and an acid anhydride group.
n is preferably an integer of 0 to 5, particularly preferably 1.

  Specific examples of the compound represented by the general formula (5) include cyclohexyl methacrylate, cyclooctyl methacrylate, phenyl methacrylate, benzyl methacrylate, tolyl methacrylate, adamantyl methacrylate, and dicyclopentanyl methacrylate. Preferably, Cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, tolyl methacrylate, adamantyl methacrylate, and dicyclopentanyl methacrylate, more preferably benzyl methacrylate, adamantyl methacrylate, and dicyclopentanyl methacrylate, and more preferably benzyl methacrylate.

  As the reactive fluidizing agent used in the present invention, a monofunctional compound having one methacryl group such as lauryl methacrylate, cyclooctenyl methacrylate, tetrahydrofurfuryl methacrylate, and methoxydiethylene glycol methacrylate, in addition to the above-mentioned compounds; A monofunctional compound having one isopropenyl group, such as isopropenylbenzene; can also be mentioned, and among these, a monofunctional compound having one methacryl group is preferable.

  The reactive fluidizing agents can be used alone or in combination of two or more. Although the compounding quantity of a reactive fluidizer is not specifically limited, Usually, 0.1-100 weight part with respect to 100 weight part of 1st crosslinkable resin or 2nd crosslinkable resin, Preferably it is 0.5-50. Part by weight, more preferably 1 to 30 parts by weight.

  As the crosslinking aid, 2 crosslinkable carbon-carbon unsaturated bonds that do not have a polymerizable carbon-carbon unsaturated bond and can participate in the crosslinking reaction of the first crosslinkable resin and / or the second crosslinkable resin are used. The polyfunctional compound which has the above is mentioned. The crosslinkable carbon-carbon unsaturated bond contained in the compound constituting the crosslinking aid is preferably present, for example, as a vinylidene group present at the molecular end, and particularly as an isopropenyl group or a methacryl group. It is more preferable that it exists as a methacryl group.

  Specific examples of the crosslinking aid include isopropenyl groups such as polyfunctional compounds having two isopropenyl groups, such as p-diisopropenylbenzene, m-diisopropenylbenzene, and o-diisopropenylbenzene. 2 or more polyfunctional compounds; ethylene dimethacrylate, 1,3-butylene dimethacrylate, 1,4-butylene dimethacrylate, 1,6-hexanediol dimethacrylate, polyethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, ethylene glycol dimethacrylate Polyfunctional compounds having two methacryl groups such as triethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and 2,2′-bis (4-methacryloxydiethoxyphenyl) propane, Chiro - such as Le propane trimethacrylate and pentaerythritol trimethacrylate, such as a polyfunctional compound having three methacryl groups, a polyfunctional compound having two or more methacryl groups; and the like. Among these, as the crosslinking aid, a polyfunctional compound having two or more methacryl groups is preferable from the viewpoint of further improving the heat resistance and crack resistance of the obtained laminate. Among polyfunctional compounds having two or more methacryl groups, polyfunctional compounds having three methacryl groups such as trimethylolpropane trimethacrylate and pentaerythritol trimethacrylate are more preferable.

  The crosslinking assistants can be used alone or in combination of two or more. The amount of the crosslinking aid is usually 0.1 to 100 parts by weight, preferably 0.5 to 50 parts by weight, more preferably 1 to 100 parts by weight of the first crosslinkable resin or the second crosslinkable resin. -30 parts by weight.

  Note that both the reactive fluidizing agent and the crosslinking aid described above are present in a substantially free state in the first crosslinkable resin and / or the second crosslinkable resin. A plasticizing effect is exhibited with respect to the crosslinkable resin and / or the second crosslinkable resin. Therefore, when these reactive fluidizing agents and crosslinking aids are added, when the prepreg obtained by the present invention is heated, the first crosslinkable resin and / or the second crosslinkable resin are melted, and an appropriate resin flow is obtained. Will show gender. On the other hand, when the heating of the prepreg is continued, the first crosslinkable resin and / or the second crosslinkable resin undergoes a crosslinking reaction, but both the above-described reactive fluidizing agent and crosslinking assistant are involved in the crosslinking reaction. As a result, it exhibits binding reactivity to the first crosslinkable resin and / or the second crosslinkable resin, so that as the crosslink reaction proceeds, the amount existing in a free state decreases, and is substantially free at the end of the crosslink reaction. It is presumed that none exist in the state. Thus, although the reactive fluidizing agent and the crosslinking aid have the same characteristics, the binding reactivity to the first crosslinking resin and / or the second crosslinking resin is higher than that of the reactive fluidizing agent. The crosslinking aid is considered to be higher, and thus the plastic effect can be expressed longer with the reactive fluidizing agent than with the crosslinking aid. The use of a crosslinking aid is preferable from the viewpoint of increasing the crosslinking density in the resulting laminate, but if the crosslinked structure is formed earlier when the prepreg is heated, the first crosslinking resin and / or the second crosslinking resin is used. The fluidity of the prepreg becomes insufficient, and the followability to other members of the prepreg surface is reduced. On the other hand, when the reactive fluidizing agent and the crosslinking aid are used in combination, even in the first crosslinking resin and / or the second crosslinking resin, even after the expression of the plastic effect by the crosslinking aid disappears. Sustainable expression of the plastic effect by the ionic fluidizing agent is expected, and the obtained laminate is preferable because the wiring embedding property, heat resistance, and crack resistance are improved in a very balanced manner. Like the reactive fluidizing agent, the crosslinking aid is preferably contained in the second resin composition constituting the outer resin layer of the prepreg.

  In the case where the reactive fluidizing agent and the crosslinking aid are blended together, the reactive fluidizing agent (simply, from the viewpoint of improving the wiring embedding property, heat resistance, and crack resistance in a balanced manner in the resulting laminate. A functional compound), a polyfunctional compound having two crosslinkable carbon-carbon unsaturated bonds (bifunctional compound), and a polyfunctional compound having three crosslinkable carbon-carbon unsaturated bonds (trifunctional compound) Are preferably used.

  The mixing ratio of the reactive fluidizing agent and the crosslinking aid may be appropriately selected as desired, but is usually 5/95 to 90/10, preferably by weight ratio (reactive fluidizing agent / crosslinking aid). Is in the range of 10/90 to 70/30, more preferably 15/85 to 70/30. By setting the blending ratio in the above range, in the prepreg, the resin fluidity of the surface during heating is improved, and in the laminate having a layer formed by crosslinking the prepreg, wiring embedding property, heat resistance and resistance Each characteristic of crack property is balanced, which is preferable.

  In addition, as a combination of the reactive fluidizing agent and the crosslinking aid, at least one compound selected from the group consisting of benzyl methacrylate, adamantyl methacrylate and dicyclopentanyl methacrylate (hereinafter referred to as reactive fluidizing agent), trimethylo -Combinations consisting of lepropane trimethacrylate (above, crosslinking aid) are mentioned. According to such a combination, even if a bifunctional compound is not included as a crosslinking aid, the resin fluidity of the surface during heating is improved in the prepreg, and the wiring embedding property, heat resistance and resistance are increased in the laminate. Each characteristic of crack property is highly balanced and is very suitable.

  When the reactive fluidizing agent and the crosslinking aid are used in combination, the blending amount (total blending amount of the reactive fluidizing agent and the crosslinking assistant) is the first crosslinking resin or the second crosslinking resin 100. It is 0.2-200 weight part normally with respect to a weight part, Preferably it is 1-100 weight part, More preferably, it is 2-60 weight part.

  Further, as described above, when the resin-impregnated reinforcing fiber layer is formed using the first polymerizable composition, or when the outer resin layer is formed using the second polymerizable composition, the first The polymerizable composition and / or the second polymerizable composition may further contain a polymerization regulator, a polymerization reaction retarding agent, a chain transfer agent, and an antiaging agent.

  The polymerization regulator is blended for the purpose of controlling the polymerization activity or improving the polymerization reaction rate. For example, trialkoxyaluminum, triphenoxyaluminum, dialkoxyalkylaluminum, alkoxydialkylaluminum, trialkyl Examples include aluminum, dialkoxyaluminum chloride, alkoxyalkylaluminum chloride, dialkylaluminum chloride, trialkoxyscandium, tetraalkoxytitanium, tetraalkoxytin, and tetraalkoxyzirconium. These polymerization regulators can be used alone or in combination of two or more. The blending amount of the polymerization regulator is, for example, in a molar ratio (metal atom in the metathesis polymerization catalyst: polymerization regulator), usually 1: 0.05 to 1: 100, preferably 1: 0.2 to 1:20. More preferably, it is in the range of 1: 0.5 to 1:10.

  The polymerization reaction retarder can suppress an increase in viscosity of the first polymerizable composition and / or the second polymerizable composition. Polymerization retarders include phosphine compounds such as triphenylphosphine, tributylphosphine, trimethylphosphine, triethylphosphine, dicyclohexylphosphine, vinyldiphenylphosphine, allyldiphenylphosphine, triallylphosphine, and styryldiphenylphosphine; Lewis such as aniline and pyridine Base; etc. can be used. What is necessary is just to adjust the compounding quantity suitably as needed.

Examples of chain transfer agents include 1-hexene, 2-hexene, styrene, vinylcyclohexane, allylamine, glycidyl acrylate, allyl glycidyl ether, ethyl vinyl ether, methyl vinyl ketone, 2- (diethylamino) ethyl acrylate, and 4-vinylaniline. Chain transfer agents having no crosslinkable carbon-carbon unsaturated bonds; divinylbenzene, vinyl methacrylate, allyl methacrylate, styryl methacrylate, allyl acrylate, undecenyl methacrylate, styryl acrylate, and ethylene glycol diacrylate A chain transfer agent having one crosslinkable carbon-carbon unsaturated bond; a chain transfer agent having two or more crosslinkable carbon-carbon unsaturated bonds, such as allyltrivinylsilane and allylmethyldivinylsilane; All It is. Among these, in the obtained laminate, those having one or more crosslinkable carbon-carbon unsaturated bonds are preferable from the viewpoint of highly balancing the properties of wiring embedding, heat resistance, and crack resistance. Those having one carbon-carbon unsaturated bond are more preferable. Among such chain transfer agents, chain transfer agents having one vinyl group and one methacryl group are preferable, and vinyl methacrylate, allyl methacrylate, styryl methacrylate, and undecenyl methacrylate are particularly preferable.
During the polymerization of the first polymerizable composition and / or the second polymerizable composition, the chain transfer agent can be bonded to the resulting polymer, but this is required when the chain transfer agent has a crosslinkable carbon-carbon unsaturated bond. Crosslinkability may be imparted to the resin contained in the first resin composition and / or the second resin composition by the carbon-carbon unsaturated bond.
These chain transfer agents can be used alone or in combination of two or more. As a compounding quantity of the chain transfer agent to the polymeric composition used for this invention, it is 0.01-10 weight part normally with respect to 100 weight part of cycloolefin monomers, Preferably it is 0.1-5 weight part. .

  Examples of the anti-aging agent include at least one anti-aging agent selected from the group consisting of a phenol-based anti-aging agent, an amine-based anti-aging agent, a phosphorus-based anti-aging agent and a sulfur-based anti-aging agent. By blending these anti-aging agents, the heat resistance of the obtained laminate can be improved to a high degree without inhibiting the crosslinking reaction, which is preferable. Among these anti-aging agents, phenol-based anti-aging agents and amine-based anti-aging agents are preferable, and phenol-based anti-aging agents are more preferable. These anti-aging agents can be used alone or in combination of two or more. The amount of the anti-aging agent is appropriately selected as desired, but is usually 0.0001 to 10 parts by weight, preferably 0.001 to 5 parts by weight, and more preferably 0 to 100 parts by weight of the cycloolefin monomer. .01 to 2 parts by weight.

  In addition, the first resin composition and / or the second resin composition (and the first polymerizable composition and / or the second polymerizable composition) include, for example, a colorant, a light stabilizer, a pigment, and a foaming agent. A compounding agent other than those described above may be contained. As the colorant, a dye or a pigment is used. There are various kinds of dyes, and known ones may be appropriately selected and used. These other compounding agents can be used alone or in combination of two or more, and the amount used is appropriately selected within a range not impairing the effects of the present invention.

(Manufacturing method of prepreg)
The prepreg of the present invention forms a resin-impregnated reinforcing fiber layer obtained by impregnating reinforcing fibers with a first resin composition containing a first crosslinkable resin and a first inorganic filler. It is manufactured by forming an outer resin layer comprising a second resin composition containing a second crosslinkable resin and a second inorganic filler on the surface.

  Such a prepreg of the present invention can be produced, for example, by the following methods (A) to (H).

(A) A first resin composition containing a first crosslinkable resin and a first inorganic filler is impregnated into a reinforcing fiber to form a resin-impregnated reinforcing fiber layer, on both surfaces of the resin-impregnated reinforcing fiber layer, A method of obtaining a prepreg by thermocompression bonding of an outer resin layer comprising a second resin composition containing a second crosslinkable resin and a second inorganic filler.
(B) The first resin composition containing the first crosslinkable resin and the first inorganic filler is impregnated into the reinforcing fiber to form a resin-impregnated reinforcing fiber layer, on both surfaces of the resin-impregnated reinforcing fiber layer, By forming an outer monomer layer composed of a second polymerizable composition containing a cycloolefin monomer, a metathesis polymerization catalyst, and a second inorganic filler, and heating the outer monomer layer, the second polymerizable composition is bulk polymerized. How to get a prepreg.
(C) A first polymerizable composition containing a cycloolefin monomer, a metathesis polymerization catalyst, and a first inorganic filler is impregnated into a reinforcing fiber to form a monomer-impregnated reinforcing fiber layer. An outer resin layer composed of a second resin composition containing a second crosslinkable resin and a second inorganic filler is formed on both surfaces, and the first polymerizable composition is bulk polymerized by heating the outer resin layer. That is how to get the prepreg.
(D) A first polymerizable composition containing a cycloolefin monomer, a metathesis polymerization catalyst, and a first inorganic filler is impregnated into a reinforcing fiber to form a monomer-impregnated reinforcing fiber layer. By forming an outer monomer layer composed of a second polymerizable composition containing a cycloolefin monomer, a metathesis polymerization catalyst, and a second inorganic filler on both surfaces, and heating the outer monomer layer, the first polymerizable composition and A method of obtaining a prepreg by bulk polymerization of the second polymerizable composition.

(E) A resin-impregnated reinforcing fiber is obtained by impregnating a reinforcing fiber with a varnish obtained by adding a solvent to the first resin composition containing the first crosslinkable resin and the first inorganic filler, and drying the solvent. A varnish formed by adding a solvent to the second resin composition containing the second crosslinkable resin and the second inorganic filler is formed on both surfaces of the resin-impregnated reinforcing fiber layer. The method of obtaining a prepreg by heat-pressing the outer side resin layer obtained by apply | coating and then drying a solvent.
(F) A resin-impregnated reinforcing fiber is obtained by impregnating a reinforcing fiber with a varnish obtained by adding a solvent to the first resin composition containing the first crosslinkable resin and the first inorganic filler, and drying the solvent. Forming a layer, and applying a varnish formed by adding a solvent to the second resin composition containing the second crosslinkable resin and the second inorganic filler on both surfaces of the resin-impregnated reinforcing fiber layer, A method of obtaining a prepreg by forming a varnish layer and removing the solvent by heating the varnish layer.
(G) A varnish formed by adding a solvent to a first resin composition containing a first crosslinkable resin and a first inorganic filler is impregnated into a reinforcing fiber to form a varnish-impregnated reinforcing fiber layer. On both surfaces of the impregnated reinforcing fiber layer, a varnish obtained by adding a solvent to the second resin composition containing the second crosslinkable resin and the second inorganic filler is applied on the substrate, and then the solvent is added. A method of obtaining a prepreg by laminating an outer resin layer obtained by drying and removing the solvent by heating.
(H) A varnish formed by adding a solvent to the first resin composition containing the first crosslinkable resin and the first inorganic filler is impregnated into the reinforcing fiber to form a varnish-impregnated reinforcing fiber layer. On both surfaces of the impregnated reinforcing fiber layer, a varnish obtained by adding a solvent to the second resin composition containing the second crosslinkable resin and the second inorganic filler is applied to form an outer varnish layer. The method of obtaining a prepreg by removing a solvent by heating.

  Among the methods (A) to (H), from the viewpoint that the interface between the resin-impregnated reinforcing fiber layer and the outer resin layer can be strengthened, (B), (C), and The method (D) is preferable, and the method (D) is more preferable.

  In the above methods (A) and (B), the method for impregnating the first resin composition into the reinforcing fiber is not particularly limited. For example, the monomer that forms the first crosslinkable resin, A composition containing an inorganic filler (for example, the first polymerizable composition described above) is applied to a known method such as a spray coating method, a dip coating method, a roll coating method, a curtain coating method, a die coating method, or a slit coating method. It can apply by applying to a reinforced fiber by a method, putting a protective film on it as needed, pressing with a roller etc. from the upper side, and then polymerizing a monomer by heating etc. then.

  In the methods (A) and (C), the method for forming the outer resin layer comprising the second resin composition containing the second crosslinkable resin and the second inorganic filler is not particularly limited. A composition containing a monomer that will form the second crosslinkable resin and a second inorganic filler (for example, the second polymerizable composition described above) is spray-coated, dip-coated, or roll-coated. Then, it is applied onto the substrate by a known method such as curtain coating method, die coating method, and slit coating method, then the monomer is polymerized by heating or the like, and the resulting polymer is peeled off from the substrate. A coalesced sheet or film can be obtained, and the outer resin layer can be formed from the sheet or film.

  In the methods (C) to (H), the method for impregnating the first polymerizable composition or varnish into the reinforcing fiber is not particularly limited. For example, the first polymerizable composition or varnish is spray-coated. Apply to the reinforcing fiber by a known method such as dip coating method, roll coating method, curtain coating method, die coating method, slit coating method, etc., and if necessary, layer a protective film on it and press with a roller or the like from above Can be performed.

  In the methods (B) to (D), the heating temperature for polymerizing the first polymerizable composition and / or the second polymerizable composition is usually 30 to 250 ° C., preferably 50 to 200. C., more preferably in the range of 90 to 150.degree. C., and when a radical generator is contained as a crosslinking agent, it is usually at most 1 minute half-life temperature of the radical generator, preferably 10 minutes of 1-minute half-life temperature. It is 20 ° C. or less, more preferably 1 minute half-life temperature. The polymerization time may be appropriately selected, but is usually 1 second to 20 minutes, preferably 10 seconds to 5 minutes. Heating the first polymerizable composition and / or the second polymerizable composition under such conditions is preferable because a prepreg with less unreacted monomer can be obtained.

  Furthermore, in the methods (E) to (H), the solvent used for diluting the first resin composition and the second resin composition to form a varnish is not particularly limited. For example, acetone, methyl ethyl ketone, toluene Xylene, methyl isobutyl ketone, ethyl acetate, ethylene glycol monomethyl ether, N, N-dimethylformamide, methanol, ethanol and the like. In addition, although the solid content density | concentration of a varnish is not specifically limited, The range of 50 mass%-80 mass% is preferable.

  Moreover, the thickness of a prepreg is although it does not specifically limit, Usually, 0.001-10 mm, Preferably it is 0.005-1 mm, More preferably, it is the range of 0.01-0.5 mm. If it exists in this range, the shaping property at the time of lamination | stacking and the mechanical strength of a laminated body, toughness, etc. will improve, and it is suitable.

  Further, the thickness of the reinforcing fiber constituting the prepreg is usually 10/100 to 4000/100, preferably 20/100 to 3000/100, more preferably 30 in terms of thickness ratio (reinforcing fiber / prepreg). / 100 to 2500/100.

  The 1st crosslinkable resin and 2nd crosslinkable resin which comprise the prepreg obtained as mentioned above do not have a crosslinked structure substantially, for example, are soluble in toluene. The molecular weight of the first crosslinkable resin and the second crosslinkable resin is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (eluent: tetrahydrofuran), and is usually 1,000 to 1,000,000. 000, preferably 5,000 to 500,000, more preferably 10,000 to 100,000. However, the first crosslinkable resin and the second crosslinkable resin may be partially crosslinked.

  Further, the resin-impregnated reinforcing fiber layer and the outer resin layer constituting the prepreg of the present invention do not necessarily have to be clearly distinguished in the vicinity of the interface. When observed by the above, it is sufficient that the resin-impregnated reinforcing fiber layer and the outer resin layer are present in a state where they can be almost confirmed.

(Laminate)
The laminate of the present invention is a laminate including at least a layer formed by crosslinking the above-described prepreg of the present invention. For example, the laminate of the present invention may have a configuration in which a plurality of layers formed by crosslinking the prepreg of the present invention are laminated, or a layer formed by crosslinking the prepreg of the present invention and other layers. May be laminated.

  For example, when the laminate of the present invention has a structure in which a layer formed by crosslinking the prepreg of the present invention and other layers are laminated, the prepreg of the present invention is arbitrarily laminated, and this A laminate of the present invention can be obtained by laminating a metal foil on the substrate, and hot-pressing and crosslinking. The metal foil preferably has a smooth surface, and the surface roughness (Rz) is a value measured by an AFM (atomic force microscope), usually 10 μm or less, preferably 5 μm or less. More preferably, it is 3 μm or less, and further preferably 2 μm or less. If the surface roughness of the metal foil is in the above range, for example, in the high-frequency circuit board obtained as the laminate of the present invention, generation of noise, delay, transmission loss and the like in high-frequency transmission is suppressed, which is preferable. The surface of the metal foil is preferably treated with a known coupling agent or adhesive such as a silane coupling agent, a thiol coupling agent, and a titanate coupling agent. The pressure at the time of hot pressing is usually 0.5 to 20 MPa, preferably 3 to 10 MPa. The hot pressing may be performed in a vacuum or a reduced pressure atmosphere. The hot pressing can be performed using a known press having a press frame mold for flat plate forming, a press molding machine such as a sheet mold compound (SMC) or a bulk mold compound (BMC).

  Since the laminate of the present invention is obtained by using the prepreg of the present invention described above, it has excellent mechanical strength and peel strength. In addition to the mechanical strength and peel strength, the laminate of the present invention is also excellent in heat resistance, drill wear resistance and insulation reliability. Therefore, the laminate of the present invention can be suitably used for a wide range of applications such as substrates of various electronic devices. In particular, the laminate of the present invention forms a conductor layer such as a circuit layer on the laminate. It is particularly suitable as a printed wiring board. Such a printed wiring board can be appropriately manufactured according to a known method using the prepreg of the present invention.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to these Examples. In addition, the part and% in an Example and a comparative example are a basis of weight unless there is particular notice.

  Each characteristic in an Example and a comparative example was measured and evaluated according to the following methods.

(1) Bending elastic modulus The bending elastic modulus of the laminate was measured according to the test method specified in JIS C-6481.

(2) Peel strength The strength when peeling the copper foil (thickness 12 μm) from the laminate was measured based on JIS C6481, and the peel strength was evaluated according to the following criteria.
A: More than 0.45 kN / m B: More than 0.4 kN / m, 0.45 kN / m or less C: 0.4 kN / m or less

Example 1
A catalyst solution was prepared by dissolving 51 parts of benzylidene (1,3-dimesityl-4-imidazolidin-2-ylidene) (tricyclohexylphosphine) ruthenium dichloride and 79 parts of triphenylphosphine in 952 parts of toluene. Separately, 100 parts of tetracyclododecene (TCD) as the cycloolefin monomer, a predetermined amount of silicon oxide (manufactured by Admatechs, trade name SOC02, average particle size 0.5 μm) as the first inorganic filler, chain transfer 0.74 parts of styrene as an agent, 2 parts of 3,3,5,7,7-pentamethyl-1,2,4-trioxepan (1 minute half-life temperature 205 ° C.) as a crosslinking agent, benzyl methacrylate as a reactive fluidizing agent 15 parts, 20 parts of trimethylolpropane trimethacrylate as a crosslinking aid, 50 parts of aluminum dimethylphosphinate as a flame retardant, and 1 part of 3,5-di-t-butyl-4-hydroxyanisole as a phenolic antioxidant A monomer solution was prepared. The said catalyst liquid was added here in the ratio of 0.12 mL per 100 g of cycloolefin monomers, and it stirred, and prepared the 1st polymeric composition.

  On the other hand, apart from the above, instead of silicon oxide as the first inorganic filler, a predetermined amount of aluminum hydroxide [made by Showa Denko KK, trade name Heidilite (registered trademark) 360, average particles as the second inorganic filler A second polymerizable composition was prepared in the same manner as described above except that the diameter was 2.7 μm.

Next, the first polymerizable composition obtained above is impregnated into a glass cloth (E glass) having a thickness of 70 μm to obtain a monomer-impregnated reinforcing fiber layer. The second polymerizable composition obtained above was applied to the surface, and this was subjected to a polymerization reaction at 120 ° C. for 5 minutes to obtain a prepreg having a thickness of 0.11 mm. The glass cloth content of the prepreg was 25% by volume.
The monomer-impregnated reinforcing fiber layer (corresponding to the first polymerizable composition layer) and the second polymerizable composition layer formed on the surface of the layer are prepared separately, and the polymerizable components constituting these layers are prepared. When the composition was subjected to a polymerization reaction to prepare a resin-impregnated reinforcing fiber layer and an outer resin layer separately, the first inorganic filler was used in 100% by volume of the first resin composition constituting the resin-impregnated reinforcing fiber layer. The content of a certain silicon oxide was 20% by volume, and the content of aluminum hydroxide as the second inorganic filler was 40% by volume in 100% by volume of the second resin composition constituting the outer resin layer.

  Next, the six prepreg sheets prepared above were stacked and further laminated with a 12 μm thick F2 copper foil (silane coupling agent-treated electrolytic copper foil, roughness Rz = 1,600 nm, manufactured by Furukawa Circuit Foil Co., Ltd.). The prepreg sheet was sandwiched, and heated and pressed at 3 MPa for 20 minutes at 205 ° C. to obtain a laminate in which the prepreg sheets were laminated. And according to the said method, each evaluation of mechanical strength and peel strength was performed about the obtained laminated body. The results are shown in Table 1.

Example 2
As the cycloolefin monomer, the prepreg and the laminate were prepared in the same manner as in Example 1 except that 80 parts of tetracyclododecene (TCD) was replaced with 80 parts of tetracyclododecene and 20 parts of dicyclopentadiene. Each characteristic was evaluated. The results are shown in Table 1.

Example 3
When preparing the first polymerizable composition, barium titanate (manufactured by Nippon Chemical Industry Co., Ltd., trade name Barcelam BT, average particle size 0.6 μm) is used as the first inorganic filler instead of silicon oxide. Except for the above, in the same manner as in Example 1, prepregs and laminates were obtained, and each characteristic was evaluated. The results are shown in Table 1.

Example 4
When preparing the second polymerizable composition, instead of aluminum hydroxide, magnesium hydroxide (manufactured by Kyowa Chemical Co., Ltd., trade name Kisuma (registered trademark) 8, average particle diameter 1.8 μm) was used as the second inorganic filler. ] Was used in the same manner as in Example 1 to obtain a prepreg and a laminate, and each characteristic was evaluated. The results are shown in Table 1.

Example 5
Except that the prepreg was produced by the following method, a prepreg and a laminate were obtained in the same manner as in Example 1, and each characteristic was evaluated.
That is, the first polymerizable composition obtained in the same manner as in Example 1 was impregnated into a glass cloth (E glass) having a thickness of 70 μm to obtain a monomer-impregnated reinforced fiber layer, and at 120 ° C. for 5 minutes. After the polymerization reaction was carried out to obtain a resin-impregnated reinforcing fiber layer, the second polymerizable composition obtained in the same manner as in Example 1 was applied, and the second polymerizable composition was polymerized at 120 ° C. for 5 minutes. By making it react, the prepreg was manufactured. The results are shown in Table 1.

Example 6
Except that the prepreg was produced by the following method, a prepreg and a laminate were obtained in the same manner as in Example 1, and each characteristic was evaluated.
That is, the second polymerizable composition obtained in the same manner as in Example 1 was applied onto a substrate, and then this was subjected to a polymerization reaction at 120 ° C. for 5 minutes. The sheet | seat for outer side resin layers was obtained by peeling from a base material. Separately from the above, the first polymerizable composition obtained in the same manner as in Example 1 was impregnated into a glass cloth (E glass) having a thickness of 70 μm to obtain a monomer-impregnated reinforcing fiber layer. Then, the obtained monomer-impregnated reinforcing fiber layer is sandwiched between the two sheets for the outer resin layer obtained above, and the first polymerizable composition is subjected to a polymerization reaction at 120 ° C. for 5 minutes, whereby a prepreg is obtained. Manufactured. The results are shown in Table 1.

Example 7
Except that the prepreg was produced by the following method, a prepreg and a laminate were obtained in the same manner as in Example 1, and each characteristic was evaluated.
That is, in Example 7, the first polymerizable composition obtained in the same manner as in Example 1 was impregnated into a glass cloth (E glass) having a thickness of 70 μm to obtain a monomer-impregnated reinforcing fiber layer. A polymerization reaction was performed at 5 ° C. for 5 minutes to obtain a resin-impregnated reinforcing fiber layer. Separately from the above, the second polymerizable composition obtained in the same manner as in Example 1 was coated on a substrate, and then polymerized at 120 ° C. for 5 minutes to obtain The obtained polymer was peeled from the substrate to obtain an outer resin layer sheet. The resin-impregnated reinforcing fiber layer obtained above was sandwiched between two sheets of the outer resin layer sheet obtained above and thermocompression bonded at 205 ° C. for 20 minutes to produce a prepreg. The results are shown in Table 1.

Comparative Example 1
In addition to silicon oxide as the first inorganic filler, a first polymerizable composition is prepared using aluminum hydroxide as the second inorganic filler, and an outer resin layer is formed from the second polymerizable composition. A prepreg was obtained in the same manner as in Example 1 except that it was not present.

  That is, the first polymerizable composition obtained was impregnated into a glass cloth (E glass) having a thickness of 70 μm, and this was subjected to a polymerization reaction at 120 ° C. for 5 minutes, whereby a thickness of 0.11 mm was obtained. A prepreg was obtained, and then, using the obtained prepreg sheet, a laminate was obtained in the same manner as in Example 1, and each characteristic was evaluated. The results are shown in Table 1. The glass cloth content of the obtained prepreg was 25% by volume.

  From Table 1, it can be seen that the laminates obtained in Examples 1 to 7 are all excellent in mechanical strength and peel strength. On the other hand, it turns out that the laminated body of the comparative example 1 obtained using the polymeric composition formed by mix | blending a 1st inorganic filler and a 2nd inorganic filler is inferior to mechanical strength and peel strength.

Claims (5)

Forming a resin-impregnated reinforcing fiber layer obtained by impregnating reinforcing fibers with the first resin composition containing the first crosslinkable resin and the first inorganic filler;
Forming an outer resin layer made of a second resin composition containing a second crosslinkable resin and a second inorganic filler on both surfaces of the resin impregnated reinforcing fiber layer. And
The method for producing a prepreg, wherein an average particle size of the first inorganic filler is less than an average particle size of the second inorganic filler.   The method for producing a prepreg according to claim 1, wherein the first crosslinkable resin and / or the second crosslinkable resin is a cycloolefin polymer.   The resin-impregnated reinforcing fiber layer is formed by impregnating the reinforcing fiber with a first polymerizable composition containing a cycloolefin monomer, a metathesis polymerization catalyst, and the first inorganic filler, and performing bulk polymerization. The method for producing a prepreg according to claim 2.   4. The outer resin layer is formed by bulk polymerization of a second polymerizable composition containing a cycloolefin monomer, a metathesis polymerization catalyst, and the second inorganic filler. Prepreg manufacturing method.   5. The average particle size of the first inorganic filler is less than 1 μm, and the average particle size of the second inorganic filler is 1 μm or more and less than 5 μm. A method for producing a prepreg.