JP2010037398A - Prepreg and laminate using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a prepreg with low dielectric loss being excellent in a wiring burying property, and to provide a laminate obtained using such a prepreg. <P>SOLUTION: In the prepreg, a reinforced fiber is impregnated with a curable resin composition containing a resin component, a crosslinking agent and a filler, the resin component contains a conjugated diene polymer and at least one aromatic vinyl-based polymer selected from the group consisting of an aromatic vinyl polymer and an aromatic vinyl-conjugated diene copolymer, and a ratio of the conjugated diene polymer to the aromatic vinyl based polymer (conjugated diene polymer/aromatic vinyl based polymer) in the resin component is in a range of 10/90-50/50 in a weight ratio. The laminate is obtained using the prepreg. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a prepreg suitable for a multilayer wiring board including an electronic circuit wiring board, and a laminate using such a prepreg.

  A circuit board is generally composed of a dielectric layer and a conductor layer. In recent years, with the advent of advanced information technology, information transmission has begun to increase in speed and frequency, and microwave communication and millimeter wave communication have become a reality. The dielectric layers of circuit boards in these high frequency eras need to reduce noise and transmission loss at high frequencies to the utmost, and as a material for forming such a dielectric layer, a dielectric with a low dielectric loss (tan δ) Material is desired.

  As such a dielectric material having a small dielectric loss, conjugated diene polymers such as polybutadiene and polyisoprene are attracting attention.

  For example, Patent Document 1 discloses a 25-50 vol% thermosetting composition comprising a polybutadiene or polyisoprene resin and an unsaturated butadiene or isoprene-containing polymer that can participate in crosslinking with the polybutadiene or polyisoprene resin. An electrical circuit material is disclosed that comprises an article, 10 to 40 volume percent woven fabric, 5 to 60 volume percent particulate filler, and a free radical cure initiator. In this patent document 1, as a specific example, a styrene-butadiene block polymer 9 having 13.5% by weight of 1,2-polybutadiene having a molecular weight of less than 5,000 at room temperature and a styrene unit content of 50% by weight as a solid polymer. A slurry is prepared by thoroughly mixing a resin component combined with 3% by weight, a granular filler, a curing agent, a flame retardant, and a coupling agent with a solvent, and the resulting slurry is reinforced with a woven web such as glass fiber. An example is disclosed in which a prepreg is produced by impregnating a material and removing the solvent, and a laminate is obtained by laminating and curing a plurality of prepregs between two copper foils.

  Patent Document 2 discloses a thermosetting composition containing a polybutadiene or polyisoprene resin in a proportion of 25 to 50% by volume of the whole, and a woven fabric containing a proportion of 10 to 40% by volume of the whole. And a wiring board material comprising a granular filler contained in a ratio of 5 to 60% by volume of the whole, a free radical curing initiator, and a flame retardant. In this Patent Document 2, as a specific example, as a resin component, 4.4% by weight of a liquid polybutadiene resin and 13.1% by weight of a styrene-butadiene-styrene triblock type copolymer are based on the total thermosetting composition. An example of using a combination (styrene unit content of 50% by weight) in combination is disclosed.

  Further, Patent Document 3 discloses a resin composition of about 10% by volume to about 75% by volume based on the total substrate, including polybutadiene or polyisoprene resin and a maximum gel penetration of about 20% by weight based on the total resin composition. A resin composition containing an ethylene-propylene rubber having a weight average molecular weight measured by chromatography of less than about 50,000, a flame retardant of about 20 to about 60 phr, and a maximum of about 50% by volume based on the total substrate. An electrical circuit material is disclosed that includes a knitted fabric, up to about 65 volume percent particulate filler based on total substrate, and a suitable amount of a peroxide curing agent. In this Patent Document 3, as specific examples, 1,3-polybutadiene liquid resin 15.73 wt%, styrene unit content 30 wt% styrene-butadiene-styrene triblock copolymer 4.53 wt%, and ethylene-propylene A thermosetting resin composition comprising a resin component comprising dicyclopentadiene liquid rubber, 65.96% by weight of 10 micron amorphous silica, 10.03% by weight of a bromine-based flame retardant and 0.75% by weight of dicumyl peroxide A product is dissolved or dispersed with a solvent to form a slurry, a glass web is immersed in the obtained slurry, a prepreg is formed by removing the solvent, and one or more layers of the obtained prepreg are laminated and laminated by heat curing. I have the goods. In Patent Document 3, a small amount of 2,2-oxalylamidobis [ethyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] is added as an antioxidant to stabilize the viscosity during operation. Techniques for improving the performance are also disclosed.

JP-A-8-208856 JP-A-10-117052 Special table 2003-528450 gazette

However, as a result of evaluation by the present inventor, it was recognized that the prepreg and the laminate described in the above-mentioned document have a problem that the wiring embedding property is insufficient.
Accordingly, an object of the present invention is to provide a prepreg having a low dielectric loss and an excellent wiring embedding property, and a laminate obtained by using the prepreg.

  As a result of intensive studies in view of the above problems, the present inventor, as a resin component, in a prepreg impregnated with a curable resin composition containing a resin component, a crosslinking agent and a filler, as a resin component; A combination of at least one aromatic vinyl polymer selected from the group consisting of a vinyl polymer and an aromatic vinyl-conjugated diene copolymer, and a conjugated diene monomer unit in a resin component By making the weight ratio between the vinyl monomer unit and the aromatic vinyl monomer unit within a specific range, the dielectric property and the wiring embedding property are highly balanced when laminated on a circuit board and cured to form a laminate. The present invention has been completed based on the finding and the findings.

  In addition to the above, the present inventor has a relatively large amount of filling in the curable resin composition for the purpose of improving heat resistance and the like by configuring the resin component contained in the curable resin composition as described above. Even if an agent is blended, heat resistance can be improved while ensuring wiring embedding in the case of a laminate, and an amine-based anti-aging agent is added to the curable resin composition. As a result, it has also been found that the wiring embeddability can be further improved when the laminate is formed without inhibiting the crosslinking activity of the prepreg.

  That is, according to the present invention, there is provided a prepreg obtained by impregnating reinforcing fibers with a curable resin composition containing a resin component, a crosslinking agent, and a filler, wherein the resin component is a conjugated diene polymer; And at least one aromatic vinyl polymer selected from the group consisting of a polymer and an aromatic vinyl-conjugated diene copolymer; and a conjugated diene monomer unit and an aromatic vinyl monomer in the resin component There is provided a prepreg having a weight ratio to a body unit (conjugated diene monomer unit / aromatic vinyl monomer unit) in the range of 10/90 to 50/50.

Preferably, the blending amount of the filler in the curable resin composition is 1-1,500 parts by weight with respect to 100 parts by weight of the conjugated diene polymer.
Preferably, the curable resin composition further includes an anti-aging agent.
Preferably, the anti-aging agent is an amine-based anti-aging agent.

  Moreover, according to this invention, the laminated body obtained by laminating | stacking one of the said prepregs, the said prepreg, or another material, and hardening | curing is provided.

  According to the present invention, it is possible to provide a prepreg with low dielectric loss and excellent wiring embedding, and a laminate obtained using such a prepreg. In particular, since the laminate of the present invention has low dielectric loss and excellent wiring embedding properties, it can be suitably used for high-frequency circuit boards such as microwaves or millimeter waves for communication equipment applications.

  The prepreg of the present invention is obtained by impregnating a reinforcing fiber with a curable resin composition containing a resin component, a crosslinking agent and a filler, and the resin component is a conjugated diene polymer; an aromatic vinyl polymer and an aromatic vinyl. -At least one aromatic vinyl polymer selected from the group consisting of conjugated diene copolymers; and the weight ratio of the conjugated diene monomer unit to the aromatic vinyl monomer unit in the resin component (Conjugated diene monomer unit / aromatic vinyl monomer unit) is from 10/90 to 50/50.

  First, each component which comprises the curable resin composition used by this invention is demonstrated.

Resin component The resin component comprises: a conjugated diene polymer; and at least one aromatic vinyl polymer selected from the group consisting of an aromatic vinyl polymer and an aromatic vinyl-conjugated diene copolymer. It is.

Conjugated Diene Polymer The conjugated diene polymer used in the present invention may be a polymer obtained by polymerizing only a conjugated diene monomer, and those generally used industrially can be used without any particular limitation. Examples of the conjugated diene monomer that forms the conjugated diene polymer include butadiene, isoprene, chloroprene, cyanobutadiene, and pentadiene. Among these, butadiene and isoprene are preferable, and butadiene is more preferable. These conjugated diene monomers can be used alone or in combination of two or more. The polymerization mode of the conjugated diene polymer is not particularly limited and may be appropriately selected depending on the purpose of use.

  Specific examples of such a conjugated diene polymer include polybutadiene, polyisoprene, polychloroprene, polycyanobutadiene, and polypentadiene. Among these, polybutadiene and polyisoprene are preferable, and polybutadiene is more preferable.

  The amount of 1,2-vinyl bonds in the conjugated diene polymer used in the present invention is not particularly limited and may be appropriately selected according to the purpose of use, but is usually 5 mol% or more, preferably 40 mol% or more, more preferably Is 60 mol% or more, more preferably 80 mol% or more. By setting the 1,2-vinyl bond amount of the conjugated diene polymer within the above range, the mechanical strength and heat resistance of the prepreg and laminate are improved, which is preferable.

  The molecular weight of the conjugated diene polymer used in the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, but the weight average molecular weight measured by gel permeation chromatography (polystyrene conversion, eluent: tetrahydrofuran). In general, it is in the range of 1,000 to 1,000,000, preferably 2,000 to 200,000, more preferably 2,500 to 10,000.

  The conjugated diene polymer of the present invention can be produced by a known method. The conjugated diene polymers may be used alone or in combination of two or more.

Aromatic vinyl polymer The aromatic vinyl polymer used in the present invention is a polymer containing an aromatic vinyl unit, and is selected from the group consisting of an aromatic vinyl polymer and an aromatic vinyl-conjugated diene copolymer. At least one kind.

  The aromatic vinyl polymer is obtained by polymerizing only an aromatic vinyl monomer. Examples of the aromatic vinyl monomer forming the aromatic vinyl polymer include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-diisopropylstyrene, 2, Examples include 4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, N, N-dimethylaminoethylstyrene, N, N-diethylaminoethylstyrene, and the like. Of these, styrene and α-methylstyrene are particularly preferable. These aromatic vinyl monomers can be used alone or in combination of two or more.

  The aromatic vinyl-conjugated diene copolymer is obtained by polymerizing only an aromatic vinyl monomer and a conjugated diene copolymer. The aromatic vinyl monomer forming the aromatic vinyl-conjugated diene copolymer is the same as the aromatic vinyl polymer, and the conjugated diene monomer is the same as the conjugated diene polymer. May be used respectively.

  The polymerization mode of the aromatic vinyl polymer and the aromatic vinyl-conjugated diene copolymer is not particularly limited, and may be appropriately selected depending on the purpose of use.

  Preferred examples of the aromatic vinyl polymer used in the present invention include polystyrene and poly α-methylstyrene, with polystyrene being particularly preferred.

  As the aromatic vinyl-conjugated diene copolymer used in the present invention, either a random copolymer or a block copolymer can be used, but the balance between wiring embeddability and crack resistance of the prepreg and the laminate. From the viewpoint of improving the quality, a block copolymer is preferred. Examples of such an aromatic vinyl-conjugated diene copolymer block copolymer include styrene-butadiene diblock copolymer, styrene-isoprene block copolymer, and styrene-butadiene-styrene triblock copolymer. Styrene-isoprene-styrene triblock copolymer, α-styrene-butadiene-α-styrene triblock copolymer, and the like. Of these, styrene-butadiene diblock copolymers and styrene-butazine-styrene triblock copolymers are preferred.

  The weight ratio of aromatic vinyl monomer unit to conjugated diene monomer unit in the aromatic vinyl-conjugated diene copolymer used in the present invention (aromatic vinyl monomer unit / conjugated diene monomer unit) is However, it is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually in the range of 30/70 to 95/5, preferably 40/60 to 90/10, more preferably 50/50 to 80/20. is there. By making the ratio of the aromatic vinyl monomer unit and the conjugated diene monomer unit within the above range, the balance of the heat resistance, mechanical strength, and wiring embedding property of the prepreg and laminate obtained is improved. Can be preferable.

  Further, the amount of 1,2-vinyl bond in the conjugated diene polymer portion in the aromatic vinyl-conjugated diene copolymer used in the present invention is not particularly limited, and may be appropriately selected according to the purpose of use. 5 mol%, preferably 15 mol% or more, more preferably 30 mol% or more. By making 1,2-vinyl bond amount into the said range, the mechanical strength and heat resistance of a prepreg and a laminated body can be improved, and it is preferable.

  The molecular weights of the aromatic vinyl polymer and aromatic vinyl-conjugated diene copolymer used in the present invention are not particularly limited, and may be appropriately selected according to the purpose of use. Gel permeation chromatography (polystyrene conversion, elution) Liquid: tetrahydrofuran), which is usually in the range of 1,000 to 1,000,000, preferably 5,000 to 500,000, more preferably 10,000 to 100,000.

  In addition, the aromatic vinyl polymer and the aromatic vinyl-conjugated diene copolymer constituting the aromatic vinyl polymer may be used alone or in combination of two or more, In the present invention, it is preferable to use a polymer containing at least an aromatic vinyl polymer as the aromatic vinyl polymer.

Weight ratio of conjugated diene monomer unit to aromatic vinyl monomer unit in resin component Weight ratio of conjugated diene monomer unit to aromatic vinyl monomer unit in resin component used in the present invention (conjugation) The diene polymer / aromatic vinyl polymer) is 10/90 to 50/50. If the weight ratio of the conjugated diene monomer unit to the aromatic vinyl monomer unit in the resin component is excessively small, the wiring embeddability of the prepreg and the laminate is inferior. . The weight ratio of the conjugated diene monomer unit to the aromatic vinyl monomer unit is preferably 20/80 to 45/55, more preferably 30/70 to 45/55.

  The resin component used in the present invention may contain a resin other than the conjugated diene polymer and the aromatic vinyl polymer within a range not impairing the effects of the present invention. In the resin component of the present invention, the content of the resin other than the conjugated diene polymer and the aromatic vinyl polymer is usually 20% by weight or less, preferably 10% by weight or less, preferably 5% by weight or less.

Cross-linking agent The cross-linking agent used in the present invention is not particularly limited as long as it can cross-link the resin component, and a radical generator is usually used.

  Examples of the radical generator include organic peroxides, diazo compounds, and nonpolar radical generators. Among these, organic peroxides and nonpolar radical generators are preferable, and organic peroxides are particularly preferable because the dielectric properties of the prepreg and laminate obtained can be improved.

  Examples of the organic peroxide include hydroperoxides such as t-butyl hydroperoxide, p-menthane hydroperoxide, 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, 2,5-dimethyl-2,5-di ( dialkyl peroxides such as 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) -2-methyl Peroxyketals such as chlorocyclohexane and 1,1-di (t-butylperoxy) cyclohexane; peroxyesters such as t-butylperoxyacetate and t-butylperoxybenzoate; t-butylperoxyisopropylcarbonate, di (isopropylperoxy) ) Peroxycarbonates such as dicarbonate; alkylsilyl peroxides such as t-butyltrimethylsilyl peroxide; 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2, And peroxyketals such as 5-di (t-butylperoxy) -3-hexyne and 1,3-di (t-butylperoxyisopropyl) benzene; Of these, dialkyl peroxides and peroxyketals are preferable.

  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, 1,1,1- And triphenyl-2-phenylethane.

  The 1-minute half-life temperature of the radical generator is appropriately selected depending on the type and use conditions of the radical generator, and is usually 50 to 350 ° C, preferably 100 to 250 ° C, more preferably 150 to 230 ° C. is there.

  These crosslinking agents can be used alone or in combination of two or more. The amount of the crosslinking agent used is usually 0.01 to 10 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the conjugated diene polymer. is there.

Filler The filler used in the present invention is not particularly limited as long as it is a particulate filler generally used industrially, but an inorganic filler is usually used.

  Examples of the inorganic filler include metal particles such as iron, copper, nickel, gold, silver, aluminum, lead, and tungsten; carbon particles such as carbon black, graphite, activated carbon, and carbon balloon; silica, silica balloon, alumina, Inorganic oxide particles such as titanium oxide, iron oxide, zinc oxide, magnesium oxide, tin oxide, antimony oxide, beryllium oxide, barium ferrite and strontium ferrite; inorganic hydroxide particles such as aluminum hydroxide and magnesium hydroxide; calcium carbonate Inorganic carbonate particles such as magnesium carbonate and sodium hydrogen carbonate; inorganic sulfate particles such as calcium sulfate; inorganic silicates such as talc, clay, mica, kaolin, fly ash, montmorillonite, calcium silicate, glass, glass balloon Particles: calcium titanate , Titanate particles such as lead zirconate titanate; aluminum nitride, silicon carbide particles and whiskers, and the like. Among these, metal particles, inorganic oxide particles, inorganic hydroxide particles, inorganic silicate particles, and the point that the balance between dielectric properties and heat resistance of the prepreg and laminate can be improved. Titanate particles and the like are preferable, and inorganic oxide particles and titanate particles are more preferable.

  These fillers can be used alone or in combination of two or more. The blending amount of the filler in the curable resin composition is usually 1-1,500 parts by weight, preferably 100-1,000 parts by weight, more preferably 300-100 parts by weight with respect to 100 parts by weight of the conjugated diene polymer. The range is 750 parts by weight. By blending the filler, the heat resistance of the resulting prepreg and laminate can be improved. In particular, by setting the blending amount of the filler within the above range, the heat resistance and wiring of the resulting prepreg and laminate can be improved. The balance with embedding property can be made favorable.

Anti-aging agent The curable resin composition used in the present invention may contain an anti-aging agent in addition to the resin component, the crosslinking agent and the filler. By incorporating an anti-aging agent into the curable resin composition, the wiring embeddability of the prepreg and the laminate can be improved.

  The anti-aging agent is not particularly limited as long as it is commonly used in the industry, but is preferably a phenol anti-aging agent, an amine anti-aging agent, a phosphorus anti-aging agent, a sulfur anti-aging agent. Agents and the like. Among these, amine-based anti-aging agents are preferable from the viewpoint that the wiring embedding property can be improved while maintaining the curing characteristics such as heat resistance.

  Examples of amine-based anti-aging agents include primary amine-based anti-aging agents and secondary amine-based anti-aging agents.

  Examples of the primary amine-based antiaging agent include aldol-α-naphthylamine, acetaldehyde aniline, p, p′-diaminodiphenylmethane, and the like.

  Examples of the secondary amine anti-aging agent include 2,2,4-trimethyl-1,2-dihydroquinoline polymer and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline. Secondary amine / ketone type anti-aging agent; N-phenyl-1-naphthylamine, octylated diphenylamine, 4,4′-bis (α, α-dimethylbenzyl) diphenylamine, p- (p-toluenesulfonylamide) diphenylamine, N, N′-di-2-naphthyl-p-phenylenediamine, N, N′-diphenyl-p-phenylenediamine, N-phenyl-N′-isopropyl-p-phenylenediamine, N-phenyl-N ′-( 1,3-dimethylbutyl) -p-phenylenediamine, N-phenyl-N ′-(3-methacryloyloxy-2-hydroxypropyl) -p-pheny Diphenylamine antioxidant such as Njiamin; and the like.

  Among these, secondary amine-based antioxidants are preferable, diphenylamine-based antioxidants having a high volatility point are more preferable, and in particular, N-phenyl-1-naphthylamine, 4,4′-bis (α, α 3-dimethylbenzyl) diphenylamine, p- (p-toluenesulfonylamido) diphenylamine, N, N′-di-2-naphthyl-p-phenylenediamine, N, N′-diphenyl-p-phenylenediamine and the like 3 A diphenylamine anti-aging agent having two or more is preferred.

  These anti-aging agents can be used alone or in combination of two or more. The blending amount of the anti-aging agent in the curable resin composition is not particularly limited and is appropriately selected depending on the purpose of use, but is usually 0.0001 to 10 parts by weight with respect to 100 parts by weight of the resin component, Preferably it is 0.001-5 weight part, More preferably, it is the range of 0.01-1 weight part.

Other compounding agents Moreover, you may mix | blend other compounding agents , such as a crosslinking adjuvant, a flame retardant, a coloring agent, dye, and a pigment, with a curable resin composition as needed. These other compounding agents can be used alone or in combination of two or more, and the compounding amount may be appropriately selected within a range not impairing the effects of the present invention.

  The curable resin composition used in the present invention can be obtained by mixing the above components. The mixing method is not particularly limited, and can be performed according to a conventional method.

Reinforcing fiber The reinforcing fiber used in the present invention is not particularly limited. For example, organic fibers such as PET (polyethylene terephthalate) fiber, aramid fiber, ultra-high molecular polyethylene fiber, polyamide (nylon) fiber, and liquid crystal polyester fiber; glass fiber , Carbon fibers, alumina fibers, tungsten fibers, molybdenum fibers, budene fibers, titanium fibers, steel fibers, boron fibers, silicon carbide fibers, silica fibers, and other inorganic 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, and H glass can be suitably used.

  These reinforcing fibers can be used alone or in combination of two or more. The compounding amount of the reinforcing fiber is not particularly limited and is appropriately selected depending on the purpose of use. In the prepreg or laminate, usually 10 to 90% by weight, preferably 20 to 80% by weight, more preferably 30 to 30%. It is in the range of 70% by weight. By setting the blending amount within this range, the balance between the dielectric properties and heat resistance of the prepreg and the laminate can be improved.

Prepreg The prepreg of the present invention is produced by impregnating the reinforcing fiber with the curable resin composition.

As an impregnation method in producing the prepreg of the present invention, a conventional method may be used, and examples thereof include a wet method and a hot melt method (dry method). Usually, a wet method is used.
According to the wet method, a resin component, a crosslinking agent, a filler, and an anti-aging agent and other compounding agents added as necessary are dissolved in a solvent to prepare a curable resin composition having a reduced viscosity, A prepreg is prepared by impregnating a reinforcing fiber with a curable resin composition having a reduced viscosity and then removing the solvent. Examples of the solvent used in the preparation of the curable resin composition having a reduced viscosity include aromatic hydrocarbon solvents such as xylene and toluene.
According to the hot melt method (dry method), a release paper is coated with a curable resin composition (substantially free of a solvent), reinforced fibers are aligned on it, and the heat-dissolved resin is rolled or A prepreg is prepared by impregnating with a doctor blade or the like and then allowing to cool.

  The drying temperature after impregnation by the wet method is usually in the range of 50 to 250 ° C., preferably 100 to 200 ° C., more preferably 120 to 170 ° C. In the present invention, in addition to the temperature range, It is more preferable to set the temperature in consideration of the one-minute half-life temperature of the radical generator (crosslinking agent) contained in the curable resin composition. That is, the drying temperature is preferably not higher than 1 minute half-life temperature of the radical generator, more preferably not more than 10 ° C. of 1-minute half-life temperature, and more preferably not more than 20 ° C. of 1-minute half-life temperature. . Here, the half-life temperature for 1 minute is a temperature at which half of the radical generator decomposes in 1 minute. For example, it is 186 ° C. for di-t-butyl peroxide and 194 ° C. for 2,5-dimethyl-2,5-bis (t-butylperoxy) -3-hexyne. The drying time may be appropriately selected, but is usually in the range of 0.1 to 120 minutes, preferably 0.5 to 60 minutes, more preferably 1 to 30 minutes.

  The thickness of the prepreg of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually 0.001 to 10 mm, preferably 0.01 to 1 mm, more preferably 0.02 to 0.2 mm. Range. By adjusting the thickness to the above range, the balance between the operability of the prepreg and the mechanical strength and toughness characteristics of the laminate obtained by curing the prepreg can be improved.

  The amount of the volatile component of the prepreg of the present invention is usually 10% by weight or less, preferably 5% by weight or less, more preferably 1% by weight or less, when it is heated at 200 ° C. for 1 hour. If the amount of volatile components in the prepreg is too large, stickiness of the prepreg will occur and the operability and storage stability will deteriorate, and voids will occur in the cured laminate, resulting in decreased appearance and mechanical strength, bleeding, This is not preferable because there is a tendency to cause problems such as deterioration in heat resistance and chemical resistance.

Laminate The laminate of the present invention is produced by laminating two or more prepregs of the present invention, shaping as necessary, and curing. Alternatively, the prepreg of the present invention is manufactured by laminating with other materials (materials other than the prepreg of the present invention), shaping as necessary, and curing.

  The other material to be laminated on the prepreg of the present invention is not particularly limited and is appropriately selected depending on the purpose of use. Examples thereof include thermoplastic resin materials and metal materials, and metal materials are particularly preferably used. It is done. As the metal material, those generally used in circuit boards can be used, and usually metal foil, preferably copper foil is used. The thickness of the metal material is not particularly limited and is appropriately selected depending on the purpose of use, but is usually 1 to 50 μm, preferably 3 to 30 μm, more preferably 5 to 20 μm, and further preferably 5 to 15 μm. .

  As a lamination and curing method in producing the laminate of the present invention, a conventional method may be followed, for example, a known press machine having a press frame mold for flat plate molding, a sheet mold compound (SMC) or a bulk mold. Heat press can be performed using a press molding machine such as a compound (BMC).

  The heating temperature at the time of lamination and curing is a temperature at which crosslinking by the radical generator occurs, and is usually higher than the 1 minute half-life temperature of the radical generator, preferably 5 ° C. higher than the 1 minute half-life temperature of the radical generator. The temperature is more preferably 10 ° C. or more higher than the one minute half-life temperature of the radical generator, and is usually in the range of 100 to 300 ° C., preferably 150 to 250 ° C. The heating time is usually in the range of 0.1 to 180 minutes, preferably 1 to 120 minutes, more preferably 2 to 20 minutes. The pressing pressure is usually 0.1 to 20 MPa, preferably 0.1 to 10 MPa, more preferably 1 to 5 MPa. Further, the hot pressing may be performed in a vacuum or a reduced pressure atmosphere.

  The laminate of the present invention thus obtained can be suitably used as a high-frequency substrate material used in a wide range because it has excellent dielectric properties in a high-frequency region and wiring embedding. Specifically, the laminate of the present invention can be suitably used for a microwave or millimeter wave high-frequency circuit board for use in communication equipment.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to these Examples. In the examples and comparative examples, “part” and “%” are based on weight unless otherwise specified.
The test and evaluation were as follows.

(1) Dielectric loss With respect to the laminate, the dielectric loss (tan δ) at 1 GHz was measured by a capacitance method using an impedance analyzer. The measurement results were evaluated according to the following criteria.
Good: 0.01 or less Poor: Over 0.01

(2) Wiring embedding property The wiring embedding property is evaluated by cutting the central portion of the multilayer body in the direction perpendicular to the wiring and observing any five cross sections of the plurality of wiring locations on the obtained cut surface. went. The results were evaluated according to the following criteria.
Good: As a result of observing 5 cross sections, a portion where wiring is not embedded is not confirmed. Bad: A portion where wiring is not embedded is confirmed among 5 cross sections.

(3) Heat resistance The heat resistance was evaluated by immersing the laminated body in a solder bath at 260 ° C. for 20 seconds and performing an overview observation on the laminated body after immersion. The results were evaluated according to the following criteria.
Good: No change in shape such as sagging, swelling, foaming, etc. Poor: Some shape change such as sagging, swelling, foaming, etc.

Example 1
100 parts of polybutadiene as a conjugated diene polymer (polybutadiene resin B3000, manufactured by Nippon Soda Co., Ltd., weight average molecular weight 3000, 1,2-vinyl bond content 95 mol%); styrene-butadiene as an aromatic vinyl polymer -100 parts of styrene triblock copolymer (weight average molecular weight 50,000, styrene unit content 50%, polybutadiene moiety 1,2-vinyl bond content 95 mol%) and polystyrene (weight average molecular weight 60,000) 175 Parts: 2 parts of di-t-butyl peroxide as a crosslinking agent; 500 parts of silica as a filler (manufactured by Admafine, volume average particle size 0.5 μm); and 4,4′-bis (α , Α-dimethylbenzyl) diphenylamine was mixed in xylene as a solvent to obtain a curable resin composition.
In the resin component, the weight ratio of the conjugated diene monomer unit to the aromatic vinyl monomer unit (butadiene unit / styrene unit) was 150/225. In addition, content of the styrene unit and the butadiene unit in the styrene-butadiene-styrene triblock copolymer was calculated by ¹ H-NMR measurement. Further, the 1,2-vinyl bond amount of the polybutadiene and the polybutadiene portion is determined from the area ratio of the unsaturated bond peak total amount and the unsaturated bond peak derived from 1,2-addition polymerization by ¹ H-NMR measurement. It was.

  Next, the obtained curable resin composition was impregnated into glass cloth (E glass) and heated to remove xylene as a solvent to prepare a sheet-like prepreg. The reinforcing fiber (glass cloth) content in the prepreg was 50%.

  Subsequently, the prepreg sheet produced above was overlaid on a circuit board (L / S = 100 μm), and heated at 200 ° C. for 10 minutes at a pressure of 3 MPa to obtain a laminate. And according to the said method, each evaluation of dielectric loss, wiring embedding property, and heat resistance was performed about the obtained laminated body. The results are shown in Table 1.

Example 2
A prepreg and a laminate were prepared in the same manner as in Example 1 except that the amount of polybutadiene was changed from 100 parts to 50 parts and the amount of polystyrene was changed from 175 parts to 100 parts. Each evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Example 3
The styrene-butadiene-styrene triblock copolymer was converted into a styrene-butadiene-styrene triblock copolymer having a weight average molecular weight of 70,000, a styrene unit content of 70%, and a 1,2-vinyl bond content of 95 mol% in the polybutadiene portion. Except for the changes, a prepreg and a laminate were produced in the same manner as in Example 1, and each evaluation was performed in the same manner as in Example 1 for the obtained laminate. The results are shown in Table 1.

Example 4
A prepreg and a laminate were prepared in the same manner as in Example 3 except that 50 parts of polybutadiene was blended, 300 parts of styrene-butadiene-styrene triblock copolymer was blended, and no polystyrene was blended. Each evaluation was performed on the laminate in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1
The blending amount of styrene-butadiene-styrene triblock copolymer was changed from 100 parts to 70 parts, polystyrene was not blended, and 4 parts of 4,4′-bis (α, α-dimethylbenzyl) diphenylamine as an anti-aging agent Prepreg and laminate in the same manner as in Example 1 except that 2 parts of 2,2-oxalylamidobis [ethyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] was blended instead of A body was prepared, and each evaluation was performed in the same manner as in Example 1 for the obtained laminate. The results are shown in Table 1.

Comparative Example 2
The blending amount of styrene-butadiene-styrene triblock copolymer was changed from 100 parts to 300 parts, polystyrene was not blended, and 4 parts of 4,4′-bis (α, α-dimethylbenzyl) diphenylamine as an anti-aging agent Prepreg and laminate in the same manner as in Example 1 except that 2 parts of 2,2-oxalylamidobis [ethyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] was blended instead of A body was prepared, and each evaluation was performed in the same manner as in Example 1 for the obtained laminate. The results are shown in Table 1.

As shown in Table 1, the laminate obtained by setting the weight ratio of the conjugated diene monomer unit to the aromatic vinyl monomer unit in the resin component constituting the curable resin composition within a predetermined range. Resulted in low dielectric loss and excellent wiring embedding and heat resistance (Examples 1 to 4).
On the other hand, when the content ratio of the aromatic vinyl monomer unit in the resin component constituting the curable resin composition is too small, the resulting laminate is inferior in wiring embedding property and heat resistance. (Comparative Examples 1-2).

Claims (5)

A prepreg formed by impregnating reinforcing fibers with a curable resin composition containing a resin component, a crosslinking agent, and a filler,
The resin component includes: a conjugated diene polymer; and at least one aromatic vinyl polymer selected from the group consisting of an aromatic vinyl polymer and an aromatic vinyl-conjugated diene copolymer. A prepreg in which the weight ratio of the conjugated diene monomer unit to the aromatic vinyl monomer unit (conjugated diene monomer unit / aromatic vinyl monomer unit) is in the range of 10/90 to 50/50.   2. The prepreg according to claim 1, wherein the amount of the filler in the curable resin composition is 1-1,500 parts by weight with respect to 100 parts by weight of the conjugated diene polymer.   The prepreg according to claim 1 or 2, wherein the curable resin composition further contains an antioxidant.   The prepreg according to claim 3, wherein the anti-aging agent is an amine-based anti-aging agent.   The laminated body obtained by laminating | stacking the prepreg in any one of Claims 1-4, the said prepreg, or another material, and hardening | curing.