Patent Description:
In recent years, an increase in the capacity of signals has been progressed in electrical equipment, and thus the materials used for semiconductor substrates and the like are desired to have dielectric characteristics such as a low dielectric constant and a low dielectric loss tangent which are required for high-speed communications.

Patent Document <NUM> proposes a thermosetting resin composition comprising: (A) a modified polyphenylene ether compound having the group of the following formula (<NUM>) at its terminal, (B) a crosslinking agent having a molecular weight of <NUM>,<NUM> or less, a functional group equivalent of <NUM> or more, and an ethylenically unsaturated double bond, (C) a hydrogenated styrene-based thermoplastic elastomer having a weight average molecular weight of <NUM>,<NUM> or more, (D) a curing accelerator, (E) an inorganic filler, and (F) a flame retardant. Patent Document <NUM> describes that the composition has excellent processability and handleability while maintaining dielectric characteristics, is capable of preventing the warpage after molding, and further, is capable of sufficiently preventing the occurrence of thermal degradation in dielectric characteristics.

(In formula (<NUM>), R<NUM> is a hydrogen atom or an alkyl group.

The metal-clad laminate plates produced using conventionally known resin compositions for a metal-clad laminate plate sometimes have insufficient heat resistance and water resistance. An object of the present invention is to provide a new resin composition for a metal-clad laminate plate capable of producing a metal-clad laminate plate having excellent heat resistance, water resistance, and the like.

The present inventors have intensively studied to solve the above problems, and as a result, found out a resin composition for a metal-clad laminate plate as defined in the claims. comprising.

That is, the present invention encompasses the following aspects.

A resin composition for a metal-clad laminate plate, comprising:.

The molecular weight distribution (Mw/Mn) of the component (A) can be <NUM> to <NUM>.

The content ratio of the component (A) to the component (B) can be component (A): component (B) = <NUM>:<NUM> to <NUM>:<NUM> in terms of weight ratio.

The resin composition for a metal-clad laminate plate can further comprise a crosslinking agent.

The resin composition for a metal-clad laminate plate can further comprise a flame retardant.

The invention also refers to a prepreg wherein the resin composition for a metal-clad laminate plate according to the invention is impregnated in a base material.

The invention also refer to a metal-clad laminate plate produced by laminating the prepreg according to (the invention and a metal foil by hot press molding.

By using the resin composition for a metal-clad laminate plate of the present invention, a metal-clad laminate plate having excellent heat resistance and water resistance can be produced.

Component (A) used in the present invention is a styrene-butadiene-styrene block copolymer (SBS) as defined in the claims.

The weight ratio of the styrene block to the butadiene block in the block copolymer comprising the butadiene block and the styrene block is <NUM>:<NUM> to <NUM>:<NUM>.

The weight average molecular weight (Mw) of the SBS block copolymer is <NUM>,<NUM> to <NUM>,<NUM>, or more than <NUM>,<NUM> to <NUM>,<NUM>. The molecular weight distribution (Mw/Mn) of the block copolymer comprising the butadiene block and the styrene block is not particularly limited, but <NUM> to <NUM>, <NUM> to <NUM>, or the like may be exemplified. The weight average molecular weight (Mw) and the molecular weight distribution (Mw/Mn) are measured by gel permeation chromatography (GPC) using polystyrene as a standard substance. The measurement conditions are as follows: a mobile phase: THF (tetrahydrofuran), a mobile phase flow rate: <NUM>/min, a column temperature: <NUM>, a sample injection volume: <NUM>µL, and a sample concentration: <NUM>% by weight.

A method for producing the SBS block copolymer used in the present invention is not particularly limited, but for example, the styrene-butadiene-styrene block copolymer may be produced by the method described in, for example, <CIT>, <CIT>, and <CIT>, and a method analogous thereto.

The component (B) used in the present invention is defined in the claims.

The molecular weight of the polybutadiene used in the present invention is a weight average molecular weight (Mw) in a range of <NUM> to <NUM>,<NUM>. The weight average molecular weight (Mw) and the number average molecular weight (Mn) are values obtained by converting data measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent based on the molecular weight of standard polystyrene.

The polybutadiene may be polybutadiene the backbone and the terminal of which are modified, or may be polybutadiene the backbone and the terminal of which are not modified. Among these, the polybutadiene the backbone and terminal of which are not modified is preferably used from the viewpoint of obtaining a cured product having high insulating properties.

As the polybutadiene, a commercial product may be used. As the commercial polybutadiene, NISSO-PB(R) B-<NUM> (manufactured by Nippon Soda Co. ), NISSO-PB B-<NUM> (manufactured by Nippon Soda Co. ), NISSO-PB B-<NUM> (manufactured by Nippon Soda Co. ), or the like may be exemplified. These polybutadienes may be used alone or used by combination of two or more thereof.

The resin composition for a metal-clad laminate plate of the present invention is a resin composition as defined in the claims.

The content ratio of the component (A) to the component (B) in the resin composition for a metal-clad laminate plate of the present invention is not particularly limited, but component (A): component (B) = <NUM>:<NUM> to <NUM>:<NUM>, <NUM>:<NUM> to <NUM>:<NUM>, <NUM>:<NUM> to <NUM>:<NUM>, <NUM>:<NUM> to <NUM>:<NUM>, or the like, in terms of a weight ratio may be exemplified.

Other additives may be appropriately added to the resin composition for a metal-clad laminate plate of the present invention, within a range not impairing the effects of the present invention. As other additives, an initiator, a crosslinking agent, a flame retardant, an inorganic filler, or the like may be exemplified.

The initiator is not particularly limited. Specifically, benzoyl peroxide, cumene hydroperoxide, <NUM>,<NUM>-dimethylhexane-<NUM>,<NUM>-dihydroperoxide, <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-di(t-butylperoxy)hexine-<NUM>, di-t-butyl peroxide, t-butylcumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-di(t-butylperoxy)hexane, dicumyl peroxide, di-t-butyl peroxyisophthalate, t-butyl peroxybenzoate, <NUM>,<NUM>-bis(t-butylperoxy)butane, <NUM>,<NUM>-bis(t-butylperoxy)octane, <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide, trimethylsilyl triphenylsilyl peroxide, or the like may be exemplified. These may be used alone or used by combination of two or more thereof.

The added amount of the initiator is not particularly limited, but an amount of <NUM> to <NUM>% by weight with respect to the combined amount of the component (A) and the component (B) may be exemplified.

The crosslinking agent is not particularly limited. Specifically, divinylbenzene, triallyl isocyanurate, or the like may be exemplified. These may be used alone or used by combination of two or more thereof.

When the crosslinking agent is added, the added amount thereof is not particularly limited, but an amount of <NUM> to <NUM>% by weight with respect to the combined amount of the component (A) and the component (B) may be exemplified.

The flame retardant is not particularly limited. Specifically, a halogen-based flame retardant such as a bromine-based flame retardant, a phosphorus-based flame retardant, or the like may be exemplified.

As the halogen-based flame retardant, a bromine-based flame retardant such as pentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether, tetrabromobisphenol A, and hexabromocyclododecane, a chlorine-based flame retardant such as chlorinated paraffin, or the like may be exemplified. These may be used alone or used by combination of two or more thereof.

As the phosphorus-based flame retardant, a phosphoric acid ester such as a condensed phosphoric acid ester and a cyclic phosphoric acid ester, a phosphazene compound such as a cyclic phosphazene compound, a phosphinate-based flame retardant such as aluminum dialkyl phosphinate, a melamine-based flame retardant such as melamine phosphate and melamine polyphosphate, or the like may be exemplified. These may be used alone or used by combination of two or more thereof.

When the flame retardant is added, the added amount thereof is not particularly limited, but an amount of <NUM> to <NUM>% by weight with respect to the combined amount of the component (A) and the component (B) may be exemplified.

As the inorganic filler, silica, alumina, talc, aluminum hydroxide, magnesium hydroxide, titanium oxide, mica, aluminum borate, barium sulfate, calcium carbonate, or the like may be exemplified. These may be used alone or used by combination of two or more thereof.

When the inorganic filler is added, the added amount thereof is not particularly limited, but an amount of <NUM> to <NUM>% by weight with respect to the combined amount of the component (A) and the component (B) may be exemplified.

The method for producing the resin composition for a metal-clad laminate plate of the present invention is not particularly limited. For example, a method in which the polybutadiene (B) and other components are added to the block copolymer comprising the butadiene block and the styrene block (A) and then kneaded with a kneading machine may be exemplified.

When a prepreg is produced, the resin composition for a metal-clad laminate plate of the present invention is often used by being prepared in a varnish form to impregnate the composition in a base material (fibrous base material) for forming the prepreg. Such a resin varnish is, for example, prepared as follows.

First, respective components that can be dissolved in an organic solvent are put in the organic solvent for dissolution. At this time, components may be heated, as needed. Thereafter, when necessary, components that cannot be dissolved in the organic solvent, such as the inorganic filler, are added and dispersed using a ball mill, a bead mill, a planetary mixer, a roll mill, or the like until a predetermined dispersion state is achieved, whereby a resin varnish is prepared.

As a method for producing a prepreg by using the obtained resin varnish, for example, a method in which the obtained resin varnish is impregnated in a fibrous base material and then dried may be exemplified.

As the fibrous base material used for producing the prepreg, specifically, glass fiber cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, printer paper, or the like may be exemplified.

The fibrous base material in which the resin varnish is impregnated is heated under desired heating conditions, for example, at <NUM> to <NUM> for <NUM> to <NUM> minutes, to remove the solvent, whereby a prepreg in a semi-cured state (B stage) can be obtained.

One or a plurality of the obtained prepregs are stacked, a metal foil such as copper foil is further stacked on both the top and bottom surfaces or on one surface of the prepreg or the prepreg stack, and this is integrally laminated by hot press molding, whereby a double-sided metal-clad or single-sided metal-clad laminate plate can be fabricated.

The hot press conditions may be appropriately set according to the thickness of the laminate plate to be produced, the kind of resin composition of the prepreg, and the like. For example, the hot press conditions may be set such that the temperature is <NUM> to <NUM>, the pressure is <NUM> to <NUM> MPa, and the time is <NUM> to <NUM> minutes.

Hereinafter, the present invention will be described in detail by way of Examples.

Into a <NUM> flask, <NUM> of tetrahydrofuran (hereinafter, abbreviated as THF) and <NUM> of hexane were added. After the mixture was cooled to -<NUM>, <NUM> of n-butyllithium (a hexane solution with a concentration of <NUM>% by weight) was added and stirred for <NUM> minutes, then <NUM> of styrene was added dropwise, and the reaction was continued for <NUM> minutes. The solution was measured by gas chromatography (hereinafter, abbreviated as GC) and the disappearance of monomers was confirmed. Then, a mixed solution of <NUM> of <NUM>,<NUM>-butadiene, <NUM> of THF, and <NUM> of hexane was added dropwise, and the reaction was continued. After the solution was measured by GC and the disappearance of monomers was confirmed, <NUM> of styrene was added dropwise, and after <NUM> minutes, <NUM> of methanol was added to terminate the reaction.

The copolymer obtained was analyzed by gel permeation chromatography (mobile phase: THF, polystyrene standards), and it was confirmed that the weight average molecular weight (Mw) was <NUM>,<NUM> and the molecular weight distribution (Mw/Mn) was <NUM>. The copolymer obtained was a copolymer having a composition ratio of PS/PB/PS = <NUM>/<NUM>/<NUM>% by weight. Note that PS means the styrene block and PB means the butadiene block. The same applies hereinafter.

The reaction liquid was washed twice with water, and then the solvent was distilled off. This was reprecipitated in methanol, filtered off, and dried in vacuo to obtain a white powder. The <NUM>,<NUM>-bonding structure in the butadiene block calculated by <NUM>H-NMR was <NUM> mol%.

Into a <NUM> flask, <NUM> of THF and <NUM> of hexane were added. After the mixture was cooled to -<NUM>, <NUM> of n-butyllithium (a hexane solution with a concentration of <NUM>% by weight) was added and stirred for <NUM> minutes, then <NUM> of styrene was added dropwise, and the reaction was continued for <NUM> minutes. The solution was measured by gas chromatography (hereinafter, abbreviated as GC) and the disappearance of monomers was confirmed. Then, a mixed solution of <NUM> of <NUM>,<NUM>-butadiene and <NUM> of THF was added dropwise and the reaction was continued. After the solution was measured by GC and the disappearance of monomers was confirmed, <NUM> of styrene was added dropwise, and after <NUM> minutes, <NUM> of methanol was added to terminate the reaction.

The copolymer obtained was analyzed by gel permeation chromatography (mobile phase: THF, polystyrene standards), and it was confirmed that the weight average molecular weight (Mw) was <NUM>,<NUM> and the molecular weight distribution (Mw/Mn) was <NUM>. The copolymer obtained was a copolymer having a composition ratio of PS/PB/PS = <NUM>/<NUM>/<NUM>% by weight.

The reaction liquid was washed twice with water, and then the solvent was distilled off. This was reprecipitated in methanol, filtered off, and dried in vacuo to obtain a colorless and transparent viscous liquid. The <NUM>,<NUM>-bonding structure in the butadiene block calculated by <NUM>H-NMR was <NUM> mol%.

Into a <NUM> flask, <NUM> of cyclohexane and <NUM> of THF were added. The mixture was warmed to <NUM>, <NUM> of n-butyllithium (a hexane solution with a concentration of <NUM>% by weight) was added and stirred for <NUM> minutes, then <NUM> of styrene was added dropwise, and the reaction was continued for <NUM> minutes. The solution was measured by gas chromatography (hereinafter, abbreviated as GC) and the disappearance of monomers was confirmed. Then, a mixed solution of <NUM> of <NUM>,<NUM>-butadiene and <NUM> of cyclohexane was added dropwise and the reaction was continued. After the solution was measured by GC and the disappearance of monomers was confirmed, <NUM> of styrene was added dropwise, and after <NUM> minutes, <NUM> of methanol was added to terminate the reaction.

Into a <NUM>,<NUM> flask, <NUM>,<NUM> of THF and <NUM> of hexane were added. After the mixture was cooled to -<NUM>, <NUM> of n-butyllithium (a hexane solution with a concentration of <NUM>% by weight) was added and stirred for <NUM> minutes, then <NUM> of styrene was added dropwise, and the reaction was continued for <NUM> minutes. The solution was measured by gas chromatography (hereinafter, abbreviated as GC) and the disappearance of monomers was confirmed. Then, a mixed solution of <NUM> of butadiene, <NUM> of THF, and <NUM> of hexane was added dropwise and the reaction was continued. After the solution was measured by GC and the disappearance of monomers was confirmed, <NUM> of styrene was added dropwise, and after <NUM> minutes, <NUM> of methanol was added to terminate the reaction.

The reaction liquid was washed twice with water, and the solvent was distilled off to obtain a white viscous liquid. The <NUM>,<NUM>-bonding structure in the butadiene unit calculated by <NUM>H-NMR was <NUM>%.

Polybutadiene (manufactured by Nippon Soda Co. , B-<NUM>), the styrene-butadiene-styrene block copolymer obtained in Production Example <NUM>, and dicumyl peroxide (manufactured by Aldrich) were mixed in an amount shown in Table <NUM> and dissolved in methyl ethyl ketone (hereinafter, referred to as MEK, manufactured by FUJIFILM Wako Pure Chemical Corporation) to obtain a varnish.

A varnish was obtained in the same manner as in Example <NUM>, except for using the styrene-butadiene-styrene block copolymer obtained in Production Example <NUM> instead of the styrene-butadiene-styrene block copolymer obtained in Production Example <NUM>.

A varnish was obtained in the same manner as in Example <NUM>, except for using Kraton D1192 (manufactured by Kraton, styrene-butadiene-styrene block copolymer) instead of the styrene-butadiene-styrene block copolymer obtained in Production Example <NUM>.

<NUM> pieces of glass fiber cloth which were cut into <NUM> squares were sufficiently impregnated with the varnish and heated in an oven at <NUM> for <NUM> minutes to fabricate prepregs. The rough surface of a copper foil having a thickness of <NUM> was applied to both surfaces of the obtained prepregs. Thereafter, this was sandwiched by polytetrafluoroethylene plates and hot-pressed using a press at <NUM> under conditions of <NUM>-<NUM> MPa for <NUM> hours to obtain an evaluation substrate (copper-clad laminate plate).

The solder heat-resistance test was measured in accordance with JIS C <NUM>. The solder heat resistance was evaluated by immersing the copper-clad laminate plate in solder at <NUM> for <NUM> minutes and observing the peeling of the copper foil. When no peeling occurred, it was evaluated as "∘," and when peeling occurred, it was evaluated as "×. " The results are shown in Table <NUM>.

<NUM> pieces of glass fiber cloth which were cut into <NUM> squares were sufficiently impregnated with the varnish and heated in an oven at <NUM> for <NUM> minutes to fabricate prepregs. <NUM> pieces of the prepregs obtained were laminated, and this was sandwiched by polytetrafluoroethylene plates and hot-pressed using a press at <NUM> under conditions of <NUM>-<NUM> MPa for <NUM> hours to obtain an evaluation substrate (laminate plate).

The Tg of the laminate plate was measured by using a dynamic viscoelasticity apparatus "RSA-G2" manufactured by TA Instruments. At this time, dynamic viscoelasticity measurement (DMA) was carried out with a bending module using a <NUM> dual cantilever as a jig at a frequency of <NUM>, and the temperature at which the tanδ was maximum when the temperature was raised from -<NUM> to <NUM> at a temperature rising rate of <NUM>/min was determined as Tg. The results are shown in Table <NUM>.

Dynamic viscoelasticity measurement (DMA) was carried out using a dynamic viscoelasticity apparatus "RSA-G2" manufactured by TA Instruments with a bending module using a <NUM> dual cantilever as a jig at a frequency of <NUM>, and when two cycles of measurements from -<NUM> to <NUM> at a temperature rising rate of <NUM>/min were carried out, the difference of Tg between the first cycle and the second cycle, ΔTg was evaluated. The temperature at which the tanδ was maximum was determined as Tg. The results are shown in Table <NUM>.

The relative dielectric constants (Dk) and dielectric loss tangents (Df) of the evaluation substrates at <NUM> were measured by the resonant cavity perturbation method. Specifically, the relative dielectric constants and dielectric loss tangents of the test substrates at <NUM> were measured using a network analyzer (MS46122B, manufactured by Anritsu Corporation). The results are shown in Table <NUM>.

These test results revealed that the Tg of the laminate plate produced using the composition of the present invention has excellent heat resistance that is higher than that of Comparative Example. block copolymer obtained in Production Example <NUM> instead of the styrene-butadiene-styrene block copolymer obtained in Production Example <NUM>.

<NUM> pieces of glass fiber cloth which were cut into <NUM> squares were sufficiently impregnated with the varnish and heated in an oven at <NUM> for <NUM> minutes to fabricate prepregs. The rough surface of a copper foil having a thickness of <NUM> was applied to both surfaces of the obtained prepregs. Thereafter, this was sandwiched by polytetrafluoroethylene plates and hot-pressed using a press at <NUM> under conditions of <NUM>-<NUM> MPa for <NUM> hours to obtain an evaluation substrate (copper-clad laminate plate).

The solder heat-resistance test was measured in accordance with JIS C <NUM>. The solder heat resistance was evaluated by immersing the copper-clad laminate plate in solder at <NUM> for <NUM> minutes and observing the peeling of the copper foil. When no peeling occurred, it was evaluated as "o," and when peeling occurred, it was evaluated as "×. " The results are shown in Table <NUM>.

The Tg of the laminate plate was measured by using a dynamic viscoelasticity apparatus "RSA-G2" manufactured by TA Instruments. At this time, dynamic viscoelasticity measurement (DMA) was carried out with a bending module using a <NUM> dual cantilever as a jig at a frequency of <NUM>, and the temperature at which the tan5 was maximum when the temperature was raised from -<NUM> to <NUM> at a temperature rising rate of <NUM>/min was determined as Tg. The results are shown in Table <NUM>.

Dynamic viscoelasticity measurement (DMA) was carried out using a dynamic viscoelasticity apparatus "RSA-G2" manufactured by TA Instruments with a bending module using a <NUM> dual cantilever as a jig at a frequency of <NUM>, and when two cycles of measurements from -<NUM> to <NUM> at a temperature rising rate of <NUM>/min were carried out, the difference of Tg between the first cycle and the second cycle, ΔTg was evaluated. The temperature at which the tan5 was maximum was determined as Tg. The results are shown in Table <NUM>.

Claim 1:
A resin composition for a metal-clad laminate plate, comprising:
(A) a styrene-butadiene-styrene block copolymer (SBS) having
i) a molar ratio of a <NUM>,<NUM>-bonding structure to a <NUM>,<NUM>-bonding structure in a butadiene block of <NUM>:<NUM> to <NUM>:<NUM> which is measured by <NUM>H NMR,
ii) a weight ratio of the styrene block to the butadiene block of <NUM>:<NUM> to <NUM>:<NUM>, and
iii) a weight average molecular weight (Mw) of <NUM>,<NUM> to <NUM>,<NUM>,
(B) a polybutadiene having
i) a molar ratio of a <NUM>,<NUM>-bonding structure to a <NUM>,<NUM>-bonding structure of <NUM>:<NUM> to <NUM>:<NUM> which is measured by <NUM>H NMR, and
ii) a weight average molecular weight (Mw) of <NUM> to <NUM>,<NUM>, and
(C) an initiator which is selected from the group consisting of benzoyl peroxide, cumene hydroperoxide, <NUM>,<NUM>-dimethylhexane-<NUM>,<NUM>-dihydroperoxide, <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-di(t-butylperoxy)hexine-<NUM>, di-t-butyl peroxide, t-butylcumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-di(t-butyl peroxy) hexane, dicumyl peroxide, di-t-butyl peroxy isophthalate, t-butyl peroxybenzoate, <NUM>,<NUM>-bis(t-butylperoxy)butane, <NUM>,<NUM>-bis(t-butylperoxy)octane, <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide and trimethylsilyl triphenylsilyl peroxide.