JP7081950B2 - Resin composition, prepreg, metal-clad laminate, and printed wiring board - Google Patents

Description

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

In recent years, with the remarkable progress of information network technology and the expansion of services utilizing information networks, electronic devices are required to have a large amount of information and a high processing speed. In order to meet these demands, substrate materials such as printed wiring boards have low dielectric constant and low dielectric constant in addition to the characteristics such as flame retardancy, heat resistance, and peel strength with copper foil, which have been conventionally required. Dielectric loss tangent is required. Therefore, further improvement of the resin composition used for the substrate such as the printed wiring board is being studied.

Polyphenylene ether (PPE) has a low dielectric constant and a low dielectric loss tangent, and is therefore suitable as a material for printed wiring boards that can meet the above-mentioned requirements. For example, the resin composition described in Patent Document 1 contains a specific modified polyphenylene ether, a specific cyanurate compound as a cross-linking agent, a copolymer of butadiene and styrene, and an organic peroxide in a predetermined ratio. , It is disclosed that a resin composition excellent in low dielectric constant and low dielectric constant contact can be obtained.

JP-A-2017-82200

The resin composition described in Patent Document 1 promotes a curing reaction (crosslinking reaction) by thermally decomposing an organic peroxide into radicals to obtain a radical polymerization initiator. In the above curing reaction, in some organic peroxides, the generated oxygen radical causes a hydrogen abstraction reaction to form a hydroxyl group in the decomposition product of the organic peroxide, so that such an organic peroxide is formed. Decomposed products of oxide may remain in a substrate such as a printed wiring board. Further, since the decomposition product of the organic ring oxide having a hydroxyl group remains in the substrate, the hygroscopicity of the substrate is increased, so that the dielectric loss tangent may not be sufficient in a high humidity environment. ..

When a substrate such as a printed wiring board is used as a material for a device such as a mobile device or an in-vehicle device, it is exposed to various environments. In particular, in an environment where environmental fluctuations such as humidity are remarkable, there is also a problem that the characteristics thereof greatly fluctuate due to the increase in hygroscopicity.

As one of the methods for solving the above problem, it is conceivable to reduce the content of the organic peroxide, but in this case, the content of the polymerization initiator is reduced, so that the content of the resin composition is reduced. The cross-linking reaction between the polyphenylene ether and the cross-linking agent is insufficient. As a result, the glass transition temperature (Tg) of a substrate such as a printed wiring board may decrease. Further, since a part of the cross-linking agent remains in a low molecular weight, there is a possibility that the heat resistance when forming a copper-clad laminate is deteriorated. Specifically, in the reflow process, the low molecular weight component may be outgas, which may break the adhesion between the copper foil and the resin and cause the copper foil surface to swell.

Therefore, the problem to be solved by the present invention is that when the resin composition is cured, it has excellent heat resistance and electrical properties (low dielectric constant and low dielectric loss tangent property), and further, electricity due to environmental changes. It is an object of the present invention to provide a resin composition, a prepreg, a metal-clad laminate, and a printed wiring board capable of suppressing fluctuations in characteristics.

As a result of diligent studies to solve the above problems, the present inventors have found a polyphenylene ether having a specific structure at the end of the main chain and having a predetermined number average molecular weight, and a cross-linking agent having a predetermined structure and number average molecular weight. The present invention has been completed by finding that a resin composition containing an organic peroxide having a predetermined structure in a predetermined ratio can solve the above-mentioned problems.

（式（１）中、ｎは、０を示し、Ｒ¹は、１～８の炭素数を有する飽和アルキル基又は不飽和アルキル基を示し、Ｒ²は、水素原子又は１～８の炭素数を有する飽和アルキル基又は不飽和アルキル基を示す。）
で表される官能基を１分子中に平均１．５～５個有し、前記ポリフェニレンエーテルの数平均分子量が、１０００以上４５００以下であり、
前記架橋剤が、炭素－炭素不飽和二重結合を１分子中に平均２個以上有し、前記架橋剤の数平均分子量が４０００以下であり、
前記ポリフェニレンエーテルと前記架橋剤との重量比が、前者：後者＝６２：３８～９５：５であり、
前記有機過酸化物が、下記式（２）又は（３）：

（式（２）中、Ｒ³及びＲ⁴は、各々独立に、１～１５の炭素数を有する１価の炭化水素基であり、Ｒ³及びＲ⁴の少なくとも一方は、芳香環を有する。式（３）中、Ｒ⁵、及びＲ⁷は、各々独立に、１～１５の炭素数を有する１価の炭化水素基であり、Ｒ⁶は、１～１５の炭素数を有する２価の炭化水素基であり、Ｒ⁵、Ｒ⁶、及びＲ⁷からなる群より選択される少なくとも一つは、芳香環を有する。）
で表される構造を有する芳香環含有ジアルキルペルオキシドであり、
前記有機過酸化物の含有量が、前記ポリフェニレンエーテル及び前記架橋剤の合計１００質量部に対し、０．０５質量部以上０．９質量部以下であり、
前記熱可塑性樹脂が、ビニル芳香族化合物とオレフィン系アルケン化合物とのブロック共重合体及びその水素添加物、並びにビニル芳香族化合物の単独重合体からなる群より選択される１種以上であり、前記ブロック共重合体又はその水素添加物のビニル芳香族化合物由来の単位の含有率が２０質量％以上であり、
前記基材が、ガラスクロスであり、前記ガラスクロスの誘電率が、５．１以下である、プリプレグ。
［２］
前記架橋剤が、トリアリルシアヌレート、トリアリルイソシアヌレート、及びポリブタジエンからなる群より選択される少なくとも一種類以上の化合物を含む［１］のプリプレグ。
［３］
前記熱可塑性樹脂の重量平均分子量が、３０，０００～３００，０００である［１］又は［２］のプリプレグ。
［４］
前記熱可塑性樹脂の含有量は、前記ポリフェニレンエーテル及び前記架橋剤の合計１００質量部に対し、２～２０質量部である［１］～［３］のいずれかのプリプレグ。
［５］
難燃剤を含み、前記難燃剤が、前記樹脂組成物中で硬化後も相溶しない難燃剤を含む［１］～［４］のいずれかのプリプレグ。
［６］
溶剤を更に含有する［１］～［５］のいずれかのプリプレグ。
［７］
前記ガラスクロスが、前記ガラスクロス１００質量部に対し、ホウ素を５．５質量部以上８．５質量部以下含む［１］～［６］のいずれかのプリプレグ。
［８］
［１］～［７］のいずれかのプリプレグと、金属箔とを積層して硬化して得られる金属張積層板。
［９］
［８］の金属張積層板から金属箔の一部が除去されていることを特徴とするプリント配線板。 That is, the present invention is as follows.
[1]
A prepreg containing a base material and a resin composition impregnated or coated on the base material.
The resin composition contains a polyphenylene ether, a cross-linking agent , an organic peroxide , and a thermoplastic resin .
The polyphenylene ether has the following formula (1): at the end of the main chain.

(In the formula (1), n represents 0 , R ¹ represents a saturated alkyl group or an unsaturated alkyl group having 1 to 8 carbon atoms, and R ² is a hydrogen atom or 1 to 8 carbon atoms. Indicates a saturated alkyl group or an unsaturated alkyl group having
Each molecule has an average of 1.5 to 5 functional groups represented by, and the number average molecular weight of the polyphenylene ether is 1000 or more and 4500 or less.
The cross-linking agent has an average of two or more carbon-carbon unsaturated double bonds in one molecule, and the number average molecular weight of the cross-linking agent is 4000 or less.
The weight ratio of the polyphenylene ether to the cross-linking agent is the former: the latter = 62: 38 to 95: 5.
The organic peroxide is the following formula (2) or (3):

In formula (2), R ³ and R ⁴ are monovalent hydrocarbon groups each independently having 1 to 15 carbon atoms, and at least one of R ³ and R ⁴ has an aromatic ring. In formula (3), R ⁵ and R ⁷ are monovalent hydrocarbon groups having 1 to 15 carbon atoms independently, and R ⁶ is a divalent hydrocarbon group having 1 to 15 carbon atoms. At least one selected from the group consisting of R ⁵ , R ⁶ , and R ⁷ which is a hydrocarbon group has an aromatic ring.)
It is an aromatic ring-containing dialkyl peroxide having a structure represented by.
The content of the organic peroxide is 0.05 parts by mass or more and 0.9 parts by mass or less with respect to 100 parts by mass in total of the polyphenylene ether and the cross-linking agent .
The thermoplastic resin is one or more selected from the group consisting of a block copolymer of a vinyl aromatic compound and an olefin-based alkene compound, a hydrogenated product thereof, and a homopolymer of the vinyl aromatic compound. The content of the unit derived from the vinyl aromatic compound of the block copolymer or its hydrogenated product is 20% by mass or more.
A prepreg in which the base material is glass cloth and the dielectric constant of the glass cloth is 5.1 or less.
[2]
The prepreg of [1], wherein the cross-linking agent contains at least one compound selected from the group consisting of triallyl cyanurate, triallyl isocyanurate, and polybutadiene.
[3 ]
The prepreg of [ 1 ] or [2] , wherein the thermoplastic resin has a weight average molecular weight of 30,000 to 300,000.
[ 4 ]
The prepreg according to any one of [1] to [3] , wherein the content of the thermoplastic resin is 2 to 20 parts by mass with respect to a total of 100 parts by mass of the polyphenylene ether and the cross-linking agent.
[ 5 ]
The prepreg according to any one of [1] to [ 4 ], which contains a flame retardant and the flame retardant is incompatible with the resin composition even after curing.
[ 6 ]
The prepreg according to any one of [1] to [ 5 ], which further contains a solvent.
[7 ]
The prepreg according to any one of [1] to [6] , wherein the glass cloth contains 5.5 parts by mass or more and 8.5 parts by mass or less of boron with respect to 100 parts by mass of the glass cloth.
[ 8 ]
A metal-clad laminate obtained by laminating and curing a prepreg according to any one of [1 ] to [ 7 ] and a metal foil.
[ 9 ]
A printed wiring board, characterized in that a part of the metal foil is removed from the metal-clad laminate of [ 8 ].

According to the present invention, when the resin composition is cured, it has excellent heat resistance and electrical properties (low dielectric constant and low dielectric loss tangent property), and can further suppress fluctuations in electrical properties due to environmental changes. A resin composition, a prepreg, a metal-clad laminate, and a printed wiring board can be provided.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not intended to be limited to these embodiments.

（式（１）中、ｎは、０又は１の整数を示し、Ｒ¹は、１～８の炭素数を有する飽和アルキル基又は不飽和アルキル基を示し、Ｒ²は、水素原子又は１～８の炭素数を有する飽和アルキル基又は不飽和アルキル基を示す。）
架橋剤は、炭素－炭素不飽和二重結合を１分子中に平均２個以上有し、前記架橋剤の数平均分子量が４０００以下である。ポリフェニレンエーテルと架橋剤との割合は、重量比で前者：後者＝６２：３８～９５：５である。有機過酸化物は、下記式（２）又は（３）：

（式（２）中、Ｒ³及びＲ⁴は、各々独立に、１～１５の炭素数を有する１価の炭化水素基であり、Ｒ³及びＲ⁴の少なくとも一方は、芳香環を有する。式（３）中、Ｒ⁵、及びＲ⁷は、各々独立に、１～１５の炭素数を有する１価の炭化水素基であり、Ｒ⁶は、１～１５の炭素数を有する２価の炭化水素基であり、Ｒ⁵、Ｒ⁶、及びＲ⁷からなる群より選択される少なくとも一つは、芳香環を有する。）
で表される構造を有する芳香環含有ジアルキルペルオキシドである。有機過酸化物の含有量は、ポリフェニレンエーテル及び架橋剤の合計１００質量部に対し、０．０５質量部以上０．９質量部以下である。本実施形態の樹脂組成物は、上記の構成を備えることにより、樹脂組成物を硬化させた際、優れた耐熱性及び電気特性（低誘電率性及び低誘電正接性）を有し、更には環境変動による電気特性の変動を抑制可能である。また、本実施形態の樹脂組成物は、上記の構成を備えることにより、樹脂組成物を硬化させた際、耐吸水性に優れ、この樹脂組成物をプリント配線板用材料として用いる際には金属箔（例えば、銅箔）との密着性に優れる。 [Resin composition]
The resin composition of the present embodiment is a resin composition containing a polyphenylene ether, a cross-linking agent, and an organic peroxide. The polyphenylene ether has an average of 1.5 to 5 functional groups represented by the following formula (1) at the end of the main chain thereof, and the number average molecular weight of the polyphenylene ether is 1000 or more and 4500 or less.

(In the formula (1), n represents 0 or an integer of 1, R ¹ represents a saturated alkyl group or an unsaturated alkyl group having 1 to 8 carbon atoms, and R ² is a hydrogen atom or 1 to 1 to. Indicates a saturated alkyl group or an unsaturated alkyl group having 8 carbon atoms.)
The cross-linking agent has an average of two or more carbon-carbon unsaturated double bonds in one molecule, and the number average molecular weight of the cross-linking agent is 4000 or less. The ratio of the polyphenylene ether to the cross-linking agent is the former: the latter = 62: 38 to 95: 5 in terms of weight ratio. The organic peroxide is represented by the following formula (2) or (3):

In formula (2), R ³ and R ⁴ are monovalent hydrocarbon groups each independently having 1 to 15 carbon atoms, and at least one of R ³ and R ⁴ has an aromatic ring. In formula (3), R ⁵ and R ⁷ are monovalent hydrocarbon groups having 1 to 15 carbon atoms independently, and R ⁶ is a divalent hydrocarbon group having 1 to 15 carbon atoms. At least one selected from the group consisting of R ⁵ , R ⁶ , and R ⁷ which is a hydrocarbon group has an aromatic ring.)
It is an aromatic ring-containing dialkyl peroxide having a structure represented by. The content of the organic peroxide is 0.05 parts by mass or more and 0.9 parts by mass or less with respect to 100 parts by mass of the total of the polyphenylene ether and the cross-linking agent. By providing the above configuration, the resin composition of the present embodiment has excellent heat resistance and electrical properties (low dielectric constant and low dielectric loss tangent property) when the resin composition is cured, and further. It is possible to suppress changes in electrical characteristics due to environmental changes. Further, the resin composition of the present embodiment is excellent in water absorption resistance when the resin composition is cured by having the above-mentioned structure, and when this resin composition is used as a material for a printed wiring board, it is a metal. Excellent adhesion to foil (for example, copper foil).

(Polyphenylene ether)
The polyphenylene ether contains a phenylene ether unit as a repeating structural unit, and the phenylene group in the phenylene ether unit may or may not have a substituent. Further, the polyphenylene ether may contain other constituent units other than the phenylene ether unit as long as the action and effect of the present invention are not impaired.

（式（Ａ）中、Ｒ⁸、Ｒ⁹、Ｒ¹⁰及びＲ¹¹は、各々独立して、水素原子、ハロゲン原子（例えば、フッ素原子、塩素原子及び臭素原子）、置換基を有してもよいアルキル基（例えば、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、ｔｅｒｔ－ブチル基等の炭素数１～６の直鎖状若しくは分岐状のアルキル基、シクロヘキシル基等の炭素数６～１０の環状のアルキル基）、置換基を有してもよいアルコキシ基（例えば、メトキシ基、エトキシ基、ブトキシ基等の炭素数１～６のアルコキシ基）、置換基を有してもよいアリール基（例えば、フェニル基及びナフチル基）、置換基を有してもよいアミノ基、ニトロ基又はカルボキシル基を表す。） The polyphenylene ether preferably contains a repeating structural unit represented by the following formula (A).

(In the formula (A), R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ may independently have a hydrogen atom, a halogen atom (for example, a fluorine atom, a chlorine atom and a bromine atom), and a substituent. A good alkyl group (eg, a linear or branched alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a cyclohexyl group, etc. It has a cyclic alkyl group having 6 to 10 carbon atoms), an alkoxy group which may have a substituent (for example, an alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an ethoxy group, and a butoxy group), and a substituent. Represents a optionally aryl group (eg, a phenyl group and a naphthyl group), an amino group which may have a substituent, a nitro group or a carboxyl group).

Specific examples of the polyphenylene ether include poly (2,6-dimethyl-1,4-phenylene ether), poly (2-methyl-6-ethyl-1,4-phenylene ether), and poly (2-methyl-). 6-Phenyl-1,4-phenylene ether), poly (2,6-dichloro-1,4-phenylene ether), 2,6-dimethylphenol and other phenols (eg 2,3,6-trimethylphenol) , 2-Methyl-6-butylphenol, etc.), and a polyphenylene ether copolymer obtained by coupling 2,6-dimethylphenol with biphenols or bisphenols, and poly (2,6). -Dimethyl-1,4-phenylene ether) and the like are heated in a toluene solvent in the presence of phenolic compounds such as bisphenols and trisphenols and organic peroxides, and are redistributed to obtain a linear structure. Alternatively, it is a polyphenylene ether having a branched structure.

The main chain terminal of the polyphenylene ether has an average of 1.5 to 5 functional groups represented by the above formula (1) (hereinafter, also referred to as "terminal functional groups") in one molecule. The terminal functional group is preferably a methacrylic group and / or an acrylic group from the viewpoint of imparting more excellent heat resistance when the resin composition is cured, and further excellent in resin fluidity during heat molding. Therefore, it is more preferable that it is a methacrylic group.

As described above, the number of terminal functional groups (average value) in one molecule of the polyphenylene ether is 1.5 to 5. The number of terminal functional groups (mean value) is preferably 1.7 to 4. When the number of terminal functional groups (average value) is 1.5 or more, the resin composition can impart sufficient heat resistance when cured. When the number of terminal functional groups (average value) is 5 or less, the resin composition can impart sufficient resin fluidity during heat molding.

The "number of terminal functional groups" as used herein is a numerical value representing the average value of functional groups per molecule of all polyphenylene ethers present in one mole of polyphenylene ether. The number of terminal functional groups can be obtained, for example, by measuring the number of hydroxyl groups remaining in the obtained polyphenylene ether and calculating the amount of decrease from the number of hydroxyl groups of the polyphenylene ether before modification. The decrease from the number of hydroxyl groups of the polyphenylene ether before this modification is the number of terminal functional groups. The method for measuring the number of hydroxyl groups in PPE before and after modification is to add a quaternary ammonium salt (tetraethylammonium hydroxide) that associates with hydroxyl groups to a solution of polyphenylene ether and measure the UV absorbance of the mixed solution. ,Desired. As a specific method for calculating the number of terminal functional groups, the method described in Examples described later can be referred to.

The number average molecular weight of polyphenylene ether is 1000 or more and 4500 or less. When the number average molecular weight is 1000 or more, the resin composition of the present embodiment is excellent in low dielectric constant and low dielectric loss tangent in the cured form. Further, since the number average molecular weight is 4500 or less, the resin composition of the present embodiment is excellent in resin fluidity at the time of heat molding. Further, since the number average molecular weight is 4500 or less, the number of cross-linking points per unit volume of the polyphenylene ether becomes a suitable value after the reaction with the cross-linking agent or the like, and due to this, in a high temperature and high humidity environment. As a result, it is possible to suppress fluctuations in electrical characteristics (low dielectric weight and low dielectric loss tangent) due to environmental changes, as will be described later. The number average molecular weight of the polyphenylene ether can be obtained in terms of standard polystyrene from the relational expression between the molecular weight of the standard polystyrene sample measured under the same conditions and the elution time by gel permeation chromatography (GPC) measurement. For a specific method for calculating the number average molecular weight, the method described in Examples described later can be referred to.

(Crosslinking agent)
The cross-linking agent preferably has a number average molecular weight of 4000 or less. By setting the molecular weight to 4000 or less, an increase in the viscosity of the varnish can be suppressed, and good resin fluidity at the time of heat molding can be obtained. The molecular weight here means a number average molecular weight when the cross-linking agent is a polymer or an oligomer. The number average molecular weight may be any one measured by a general molecular weight measuring method, and specific examples thereof include values measured by using GPC.

The cross-linking agent has an average of two or more carbon-carbon unsaturated double bonds in one molecule, and the number average molecular weight of the cross-linking agent is 4000 or less. The cross-linking agent may be composed of one kind of compound or two or more kinds of compounds. As used herein, the term "carbon-carbon unsaturated double bond" refers to a double bond located at the end branched from the main chain when the cross-linking agent is a polymer or oligomer. Examples of carbon-carbon unsaturated double bonds include 1,2-vinyl bonds in polybutadiene.

When the number average molecular weight of the cross-linking agent is less than 600, the number of carbon-carbon unsaturated double bonds (average value) per molecule of the cross-linking agent is preferably 2 to 4. When the number average molecular weight of the cross-linking agent is less than 600 to 1500, the number of carbon-carbon unsaturated double bonds (average value) per molecule of the cross-linking agent is preferably 4 to 26. Number of Crosslinkers When the average molecular weight is 1500 to 4000, the number of carbon-carbon unsaturated double bonds (average value) per molecule of the crosslinker is preferably 26 to 60. When the number average molecular weight of the cross-linking agent is within the above range and the number of carbon-carbon unsaturated double bonds is equal to or more than a specific value, the resin composition of the present embodiment further enhances the reactivity of the cross-linking agent and is a resin. The cross-linking density of the cured product of the composition is further improved, and as a result, more excellent heat resistance can be imparted. On the other hand, when the number average molecular weight of the cross-linking agent is within the above range and the number of carbon-carbon unsaturated double bonds is not more than a specific value, more excellent resin fluidity can be imparted during heat molding.

Examples of the cross-linking agent include a trialkenyl isocyanurate compound such as triallyl isocyanurate (TAIC), a trialkenyl cyanurate compound such as triallyl cyanurate (TAC), and a polyfunctional methacrylate having two or more methacrylic groups in the molecule. Compounds, polyfunctional acrylate compounds having two or more acrylic groups in the molecule, polyfunctional vinyl compounds having two or more vinyl groups in the molecule such as polybutadiene, vinyl benzyl compounds such as divinylbenzene having vinyl benzyl groups in the molecule. , 4,4'-Bismaleimide Diphenylmethane and the like have polyfunctional maleimide compounds having two or more maleimide groups in the molecule. These cross-linking agents may be used alone or in combination of two or more. Among these, the cross-linking agent preferably contains at least one compound selected from the group consisting of triallyl cyanurate, triallyl isocyanurate, and polybutadiene. When these cross-linking agents contain one or more of the above compounds, the cross-linking density becomes higher during the curing reaction (cross-linking reaction), which tends to further improve the heat resistance of the cured product of the resin composition.

The weight ratio of the polyphenylene ether to the cross-linking agent is preferably the former: the latter = 62: 38 to 95: 5. When the weight ratio is 62:38 or more, the resin composition of the present embodiment has an excellent low dielectric constant and low dielectric loss tangent when cured. When the weight ratio is 95: 5 or less, the resin composition of the present embodiment improves the cross-linking density of the cross-linked structure formed by the polyphenylene ether and the cross-linking agent, and as a result, has excellent heat resistance when cured. Has sex. From the same viewpoint, the weight ratio is more preferably 68:32 to 85:15.

（式（２）中、Ｒ³及びＲ⁴は、各々独立に、１～１５の炭素数を有する１価の炭化水素基であり、Ｒ³及びＲ⁴の少なくとも一方は、芳香環を有する。式（３）中、Ｒ⁵、及びＲ⁷は、各々独立に、１～１５の炭素数を有する１価の炭化水素基であり、Ｒ⁶は、１～１５の炭素数を有する２価の炭化水素基であり、Ｒ⁵、Ｒ⁶、及びＲ⁷からなる群より選択される少なくとも一つは、芳香環を有する。） (Organic peroxide)
The organic peroxide is an aromatic ring-containing dialkyl peroxide having a structure represented by the following formula (2) or (3).

In formula (2), R ³ and R ⁴ are monovalent hydrocarbon groups each independently having 1 to 15 carbon atoms, and at least one of R ³ and R ⁴ has an aromatic ring. In formula (3), R ⁵ and R ⁷ are monovalent hydrocarbon groups having 1 to 15 carbon atoms independently, and R ⁶ is a divalent hydrocarbon group having 1 to 15 carbon atoms. At least one selected from the group consisting of R ⁵ , R ⁶ , and R ⁷ which is a hydrocarbon group has an aromatic ring.)

Examples of the monovalent hydrocarbon group having 1 to 15 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group and a pentyl group. Linear or branched alkyl groups such as hexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl group and decyl group, cyclic alkyl group such as cyclopropyl, cyclobutyl group, cyclopentyl group and cyclohexyl group, phenyl group, Examples thereof include an aryl group such as a trill group and a naphthyl group, and an aralkyl group such as a benzyl group and a benzylethyl group. Examples of the divalent hydrocarbon group having 1 to 15 carbon atoms include an alkylene group such as a methylene group, an ethylene group, a trimethylene group, a propylene group, a tetramethylene group, an ethylethylene group, a pentamethylene group and a hexamethylene group. , Alylen groups such as a phenylene group and a naphthylene group can be mentioned.

At least one selected from the group consisting of R ⁵ , R ⁶ , and R ⁷ has an aromatic ring. Examples of the aromatic ring include a benzene ring and a naphthalene ring, and a benzene ring is preferable for the reason described later.

The resin composition of the present embodiment is excellent in heat resistance when cured even if the content of the aromatic ring-containing dialkyl peroxide in the resin composition is reduced. This is presumed for the following reasons, but this presumption does not limit the present invention in any way. That is, it is presumed that the unit structures of the aromatic ring and the polyphenylene ether in the aromatic ring-containing dialkyl peroxide have relatively high compatibility because of the similarity of the structures. As a result, the aromatic ring-containing dialkyl peroxide functions as a reaction initiator that can increase the crosslink density of the crosslinked structure formed by the reaction between the polyphenylene ether and the crosslinking agent even if the content is small. It is presumed to be. Further, as will be described later, even if the content of the aromatic ring-containing dialkyl peroxide is small, the ability to increase the crosslink density can reduce the water absorption rate of the cured product, and further contribute to low dielectric constant and low dielectric loss tangent. preferable.

Examples of the aromatic ring-containing dialkyl peroxide which is an organic peroxide include t-butylcumyl peroxide, bis (1-tert-butylperoxy-1-methylethyl) benzene, and 2-phenyl-2-[(2-phenyl-2-]. Phenylpropane-2-yl) Peroxy] Propane can be mentioned. These organic peroxides may be used alone or in combination of two or more.

Among these, the aromatic ring-containing dialkyl peroxide is bis (1-tert-butylperoxy-1-) from the viewpoint of further excellent heat resistance, mechanical properties and electrical properties (low dielectric constant and low dielectric loss tangent) when cured. Methylethyl) benzene is preferred.

The content of the organic peroxide is 0.05 to 0.9 parts by mass with respect to 100 parts by mass of the total of the polyphenylene ether and the cross-linking agent. When the content of the organic peroxide is 0.05 parts by mass or more, the resin composition of the present embodiment tends to have more excellent heat resistance when cured. When the content of the organic peroxide is 0.9 parts by mass or less, the resin composition of the present embodiment tends to have a lower dielectric constant and a low dielectric loss tangent when cured, and has a humidity and the like. There is a tendency to further reduce changes in permittivity and dielectric loss tangent due to environmental changes. From the same viewpoint, the content is preferably 0.15 to 0.8 parts by mass, more preferably 0.3 to 0.7 parts by mass.

The reason why the fluctuation can be suppressed by providing the aromatic ring-containing dialkyl peroxide in the resin composition of the present embodiment is presumed as follows. However, the present invention is not limited to this speculation. That is, it is considered that the reaction product of the organic peroxide contributes. In organic peroxides, the peroxide structure is decomposed by heat during heat molding, and radicals are generated. This radical is added to a carbon-carbon unsaturated double bond or the like and acts as an initiator of a polymerization reaction, and also causes a hydrogen abstraction reaction from a monomer, a polymer or the like. In general dialkyl peroxide, this hydrogen extraction performance is relatively high, and the cured product of the resin composition contains a product of a hydrogen extraction reaction, that is, a compound having a hydroxyl group. A compound having a hydroxyl group itself tends to not only deteriorate (increase) the dielectric constant and the dielectric loss tangent, but also increase the hygroscopicity of the cured product. When the environment such as humidity changes, the amount of water contained in the cured product also changes due to its hygroscopicity. Moisture is a factor that deteriorates (increases) the dielectric constant and the dielectric loss tangent, and the more the cured product contains a compound having a hydroxyl group, the larger the fluctuation of the dielectric constant and the dielectric loss tangent due to the environmental change becomes. On the other hand, in the aromatic ring-containing dialkyl peroxide of the present embodiment, the polyphenylene ether and the cross-linking agent can be suitably cross-linked, and the amount used thereof can be reduced. As a result, excellent heat resistance is imparted to the cured product of the resin composition, and even in an environment with severe environmental fluctuations, only a small amount of hydrogen abstraction reaction product is produced, so that fluctuations in dielectric constant and dielectric loss tangent can be suppressed. Guessed.

(Thermoplastic resin)
The resin composition preferably contains a thermoplastic resin. The thermoplastic resin is a hydrogenated product obtained by hydrogenating a block copolymer of a vinyl aromatic compound and an olefin-based alkene compound and a hydrogenated product thereof (a block copolymer of a vinyl aromatic compound and an olefin-based alkene compound). It is preferably one or more selected from the group consisting of a block copolymer) and a homopolymer of a vinyl aromatic compound. The content of the unit derived from the vinyl aromatic compound of the block copolymer or its hydrogenated product is preferably 20% by mass or more. The vinyl aromatic compound may have an aromatic ring and a vinyl group in the molecule, and examples thereof include styrene. The olefin-based alkene compound may be an alkene having a linear or branched structure in the molecule, and examples thereof include ethylene, propylene, butylene, isobutylene, butadiene, and isoprene. Among these, the thermoplastic resin is a styrene-butadiene block copolymer, a styrene-ethylene-butadiene block copolymer, a styrene-ethylene-butylene block copolymer, and styrene from the viewpoint of further excellent compatibility with the polyphenylene ether. -Butadiene-butylene block copolymer, styrene-isoprene block copolymer, styrene-ethylene-propylene block copolymer, styrene-isobutylene block copolymer, hydrogenated additive of styrene-butadiene block copolymer, styrene-ethylene -From a group consisting of a hydrogenated product of a butadiene block copolymer, a hydrogenated product of a styrene-butadiene-butylene block copolymer, a hydrogenated product of a styrene-isoprene block copolymer, and a homopolymer of styrene (polystyrene). It is preferably one or more selected, and more preferably one or more selected from the group consisting of a styrene-butadiene block copolymer, a hydrogenated additive of a styrene-butadiene block copolymer, and polystyrene. .. Further, when the content of the unit derived from the vinyl aromatic compound of the block copolymer or its hydrogenated product is 20% by mass or more, the compatibility with the polyphenylene ether is further improved, and the adhesion strength with the metal foil is further improved. Tends to improve further.

The hydrogenation rate of the hydrogenated product is not particularly limited, and a part of the carbon-carbon unsaturated double bond derived from the olefin-based alkene compound may remain.

The weight average molecular weight of the thermoplastic resin is preferably 300000 to 300,000. Since the weight average molecular weight is 300000 or more, the resin composition of the present embodiment tends to have further excellent heat resistance when cured. Since the weight average molecular weight is 300,000 or less, the resin composition of the present embodiment tends to have better resin fluidity at the time of heat molding. The weight average molecular weight is determined by the method described in Examples described later.

The content of the thermoplastic resin is preferably 2 to 20 parts by mass with respect to 100 parts by mass in total of the polystyrene ether and the cross-linking agent. When the content is 2 parts by mass or more, the resin composition of the present embodiment tends to be more excellent in low dielectric constant, low dielectric loss tangent property and adhesion to the metal leaf when cured. When the content is 20 parts by mass or less, the resin composition of the present embodiment tends to have more excellent resin fluidity at the time of heat molding.

(Flame retardants)
The resin composition of the present embodiment preferably contains a flame retardant. The flame retardant is not particularly limited as long as it is incompatible with the polyphenylene ether or the cross-linking agent even after curing from the viewpoint of improving heat resistance. Examples of the flame retardant include inorganic flame retardants such as antimony trioxide, aluminum hydroxide, magnesium hydroxide and zinc borate, hexabromobenzene, decabromodiphenylethane, 4,4-dibromobiphenyl, ethylenebistetrabromophthalimide and the like. Examples thereof include a phosphorus-based flame retardant such as an aromatic bromine compound, resorcinol bis-diphenyl phosphate, and resorcinol bis-dixylenyl phosphate. These flame retardants may be used alone or in combination of two or more. Among these, the flame retardant is preferably decabromodiphenylethane from the viewpoint of further excellent low dielectric constant and low dielectric loss tangent when the resin composition is cured.

The content of the flame retardant is not particularly limited, but is preferably 5 parts by mass or more with respect to a total of 100 parts by mass of the polyphenylene ether resin and the cross-linking agent from the viewpoint of maintaining the flame retardancy of UL standard 94V-0 level. It is more preferably 10 parts by mass or more, still more preferably 15 parts by mass or more. Further, from the viewpoint that the dielectric constant and the dielectric loss tangent of the obtained cured product can be kept low, the content is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, and further preferably 40 parts by mass or less.

(Silica filler)
The resin composition of the present embodiment may contain a silica filler. Examples of the silica filler include natural silica, fused silica, synthetic silica, amorphous silica, Aerosil, and hollow silica. The content of the silica filler may be about 10 to 100 parts by mass with respect to 100 parts by mass of the total of the polyphenylene ether and the cross-linking agent. Further, the surface of the silica filler may be surface-treated with a silane coupling agent or the like.

The resin composition of the present embodiment may contain other flame retardants, heat stabilizers, antioxidants, UV absorbers, surfactants, lubricants, other additives and the like.

The resin composition of the present embodiment may further contain a solvent. In this case, the resin composition of the present embodiment may be in the form of a varnish in which the solid component in the resin composition is dissolved or dispersed in a solvent.

<solvent>
From the viewpoint of solubility, the solvent is preferably an aromatic compound such as toluene or xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, and chloroform. These solvents may be used alone or in combination of two or more.

The prepreg of the present embodiment includes a base material and the resin composition of the present embodiment impregnated or coated on the base material. The prepreg can be obtained, for example, by impregnating the varnish with a base material such as glass cloth and then drying and removing the solvent component with a hot air dryer or the like.

As the base material, various glass cloths such as roving cloths, cloths, chopped mats and surfaced mats; asbestos cloths, metal fiber cloths, and other synthetic or natural inorganic fiber cloths; all aromatic polyamide fibers, all aromatic polyesters. Woven or non-woven fabrics obtained from liquid crystal fibers such as fibers and polybenzoxazole fibers; natural fiber cloths such as cotton cloth, linen cloth and felt; carbon fiber cloth, kraft paper, cotton paper, cloth obtained from paper-glass mixed fiber yarn, etc. Natural cellulose-based base material; polytetrafluoroethylene porous film and the like can be mentioned. These base materials may be used alone or in combination of two or more.

The base material is preferably glass cloth. The dielectric constant of the glass cloth is preferably 5.1 or less, and more preferably 4.9 or less. Since the base material is glass cloth, the heat resistance of the laminated board can be further improved, and the coefficient of thermal expansion tends to be further reduced. When the dielectric constant of the glass cloth is 5.1 or less, the increase in the dielectric constant of the laminated plate tends to be further suppressed as compared with the E glass cloth or the like described later.

The dielectric constant of the glass cloth is a value at 10 GHz measured by the cavity resonance method described later using a sample processed into a lump instead of the cloth.

The prepreg preferably contains 5.5 to 8.5 parts by mass of boron with respect to 100 parts by mass of the glass cloth. As a result, the prepreg can further reduce the coefficient of thermal expansion. Further, when the boron content is 5.5 mass or more, the dielectric constant and the dielectric loss tangent can be further reduced, and the drill workability tends to be further improved. When the boron content is 8.5 parts by mass or less, the heat resistance tends to be further improved, and the fluctuation range of the dielectric constant and the dielectric loss tangent due to environmental changes such as humidity tends to be further reduced. .. This cause is considered to be derived from the manufacturing process of the glass cloth, but this speculation does not limit the present invention in any way.

As a method for measuring the boron content of the glass cloth, the method described in Examples described later is used.

The proportion of the solid content of the resin composition of the present embodiment in the prepreg is preferably 30 to 80% by mass, more preferably 40 to 70% by mass. When the above ratio is 30% by mass or more, the insulation reliability tends to be further improved when the prepreg is used for an electronic substrate or the like. When the above ratio is 80% by mass or less, it tends to be more excellent in mechanical properties such as bending elastic modulus when it is desired to have it for an electronic substrate or the like.

[Metal-clad laminate]
The metal-clad laminate of the present embodiment is obtained by laminating and curing the resin composition of the present embodiment or the prepreg of the present embodiment and a metal foil. The metal-clad laminate preferably has a form in which a cured product of a prepreg (also referred to as a “cured product complex”) and a metal foil are laminated and adhered to each other, and is preferably used as a material for an electronic substrate. Examples of the metal foil include aluminum foil and copper foil, and among these, copper foil is preferable because it has low electrical resistance. The cured product complex to be combined with the metal foil may be one sheet or a plurality of sheets, and depending on the intended use, the metal foil is laminated on one side or both sides of the composite and processed into a laminated plate. As a method for producing a laminated board, for example, a composite composed of a thermosetting resin composition and a base material (for example, the above-mentioned prepreg) is formed, and after laminating this with a metal foil, the thermosetting resin is produced. Examples thereof include a method of obtaining a laminated plate in which a cured product laminate and a metal foil are laminated by curing the composition. One of the particularly preferable uses of the laminated board is a printed wiring board. It is preferable that at least a part of the metal foil is removed from the metal-clad laminated board of the printed wiring board.

[Printed wiring board]
In the printed wiring board of the present embodiment, a part of the metal foil is removed from the metal-clad laminated board. The printed wiring board of the present embodiment can be typically formed by a method of pressure heating molding using the prepreg of the present invention described above. Examples of the base material include the same as described above for the prepreg. The printed wiring board of the present embodiment has excellent heat resistance and electrical characteristics (low dielectric constant and low dielectric loss tangent) by containing the resin composition of the present embodiment, and further has electrical characteristics due to environmental changes. It is possible to suppress fluctuations, and it also has excellent insulation reliability and mechanical properties.

Hereinafter, the present embodiment will be specifically described with reference to Examples, but the present embodiment is not limited to the following Examples.

Each of the physical properties described in the following Examples and Comparative Examples was evaluated by the following measuring methods.
(1) Number average molecular weight of PPE, weight average molecular weight of thermoplastic resin Using GPC analysis, the number average molecular weight of PPE and the weight average molecular weight of the thermoplastic resin were determined by comparison with the elution time of standard polystyrene having a known molecular weight. Specifically, after preparing a measurement sample having a sample concentration of 0.2 w / vol% (solvent: chloroform), HLC-8220 GPC (manufactured by Toso Co., Ltd.) is used as the measuring device, and the column: Shodex GPC KF-405L HQ ×. Measurement was performed under the conditions of 3 (manufactured by Showa Denko KK), eluent: chloroform, injection amount: 20 μL, flow rate: 0.3 mL / min, column temperature: 40 ° C., detector: RI.

(2) Average number of terminal functional groups of PPE The average number of terminal functional groups per molecule of PPE was determined by the following method. That is, a sample obtained by adding a tetramethylammonium hydroxide solution to a methylene chloride solution of PPE in accordance with the method described in "Polymer Proceedings, vol.51, No. 7 (1994), p. 480". The change in absorbance at a wavelength of 318 nm was measured with an ultraviolet-visible absorptiometer. From this measured value, the number of phenolic hydroxyl groups before and after the terminal denaturation of PPE was determined. Further, the number of molecules of PPE (number average number of molecules) was determined by using the number average molecular weight of PPE obtained by the method (1) above and the mass of PPE.
From these values, the average number of phenolic hydroxyl groups per PPE molecule before and after denaturation was determined according to the following formula (1).
Average number of phenolic hydroxyl groups per molecule = number of phenolic hydroxyl groups / number of average molecules ... (1)
For the average number of terminal functional groups after modification, the average number of terminal functional groups after modification was determined according to the following formula (2).
Average number of terminal functional groups per molecule = average number of phenolic hydroxyl groups before modification-average number of phenolic hydroxyl groups after modification ... (2)

(3) Dielectric constant and dielectric loss tangent of laminated plate and glass sample The dielectric constant and dielectric loss tangent of the laminated board and glass sample at 10 GHz were measured by the cavity resonance method. As a measuring device, a network analyzer (N5230A, manufactured by Agilent Technologies) and a cavity resonator (Cavity Resonator CP series) manufactured by Kanto Electronics Applied Development Co., Ltd. were used. A laminated plate or glass sample having a thickness of about 0.5 mm was cut into a size of about 2 mm in width and 50 mm in length so that the warp of the glass cloth was on the long side, and two same samples were prepared. .. Next, the two samples were placed in an oven at 105 ° C. ± 2 ° C. and dried for 2 hours, and then one sample had a relative humidity of 23 ° C. of 50 ± 5% and the other sample had a relative humidity of 40 ° C. of 85 ±. It was allowed to stand in a 5% environment for 96 ± 5 hours. Then, the dielectric constant and the dielectric loss tangent of each of the two samples were measured by using the above measuring device in an environment of 23 ° C. and a relative humidity of 50 ± 5%.

(4) Glass transition temperature of the laminated plate The dynamic viscoelasticity of the laminated plate was measured, and the temperature at which tan δ was maximized was determined as the glass transition temperature (Tg). A dynamic viscoelastic device (RHEOVIBRON model DDV-01FP, manufactured by ORIENTEC) was used as the measuring device. A laminated plate having a thickness of about 0.3 mm is cut into a length of about 35 mm and a width of about 5 mm so that the warp of the glass cloth described later has a long side, and used as a test piece. The measurement was performed at.

(5) Water absorption rate of the laminated board The laminated board was subjected to a water absorption acceleration test, and the water absorption rate was obtained from the increased mass. A laminated plate having a thickness of about 0.3 mm was cut into a 50 mm square to prepare a test piece. After drying this test piece at 105 ° C. for 60 minutes, the mass was measured and used as the mass (g) before the accelerated test. Next, the mass after performing the water absorption acceleration test under the conditions of temperature: 121 ° C., pressure: 2 atm, and time: 4 hours was measured and used as the mass (g) after the acceleration test. Using the mass (g) before the accelerated test and the mass (g) after the accelerated test, the following formula (3):
Water absorption rate (mass%)
= (Mass before accelerated test-Mass after accelerated test) / Mass before accelerated test x 100 ... (3)
The water absorption rate was calculated by the above method, and the average value of the measured values of the four test pieces was obtained.

(6) Solder heat resistance after water absorption test of laminated board Using the laminated board after measuring the water absorption rate described in (5) above, a solder heat resistance test at 288 ° C. was performed. The laminated plate after the water absorption acceleration test was immersed in a solder bath at 288 ° C. for 20 seconds and visually observed. Laminated plates in which no swelling, peeling, or whitening was confirmed even when immersed in a solder bath were evaluated as "○ (good)". Further, the laminated board in which any of swelling, peeling and whitening occurred due to immersion in the solder bath was evaluated as "x (defective)".

(7) Copper foil peeling strength of laminated board (copper foil peeling strength N / mm)
The stress when peeling the copper foil of the copper-clad laminate at a constant speed was measured. A copper-clad laminate using a 35 μm thick copper foil (GTS-MP foil manufactured by Furukawa Denki Kogyo Co., Ltd.) produced by the method described later was cut into a size of 15 mm in width × 150 mm in length, and an autograph (AG-) was cut out. Using 5000D (manufactured by Shimadzu Corporation), measure the average value of the load when the copper foil is peeled off at an angle of 90 ° C to the removal surface at a speed of 50 mm / min, and measure the average value of the five measurements. I asked.

(8) Resin flow amount at the time of heat molding of the laminated board The resin flow amount at the time of heat molding of the laminated board was obtained by the following method.
A prepreg having a resin composition content of 58% by mass was cut into 10 cm squares, and four of them were laminated and heat-molded by a method described later. The weight (g) and the size before heat-molding (10 cm). Using the weight (g) of the laminated board from which the cured product of the resin composition flowing out from the corner) was removed, the following formula (4):
Resin flow amount (mass%)
= (Weight of laminated board before removal of flowing part-Weight of laminated board after removal) / Weight of laminated board before removal × 100 ... (4)
Was calculated by

(9) Content of Boron in Glass Cloth The weighed glass cloth was melted with sodium carbonate and then melted with dilute nitric acid to give a constant volume. The boron content of this solution was measured by the ICP method with a measuring device (PS3520 VDDII, manufactured by Hitachi High-Tech Science Co., Ltd.).

Each component used in the following Examples and Comparative Examples is as follows.
"PPE"
-Terminal methacrylic acid modified PPE "Product name SA9000"
(Manufactured by Sabic Innovative Plastics, Mn: 2756, number of terminal functional groups: 2.0)
-PPE-A (synthesized by the method described later, Mn: 2150, number of terminal functional groups: 2.8)
-PPE-B (synthesized by the method described later, Mn: 3240, number of terminal functional groups: 2.9)
-PPE-C (synthesized by the method described later, Mn: 4250, number of terminal functional groups: 2.9)

"Crosslinking agent"
・ TAIC (manufactured by Nihon Kasei Co., Ltd., molecular weight: 249.7, number of unsaturated double bonds: 3)
-TAC (manufactured by Kayaku Akzo, molecular weight: 249, number of unsaturated double bonds: 3)
-Polybutadiene "Product name B-1000"
(Manufactured by Nippon Soda, Mn: 1200, number of unsaturated double bonds: 18.4)
-Polybutadiene "Product name B-2000"
(Manufactured by Nippon Soda, Mn: 2100, number of unsaturated double bonds: 34.4)

"Organic peroxide"
・ Bis (1-tert-butylperoxy-1-methylethyl) benzene "Product name Perbutyl P" (manufactured by NOF CORPORATION)
-2-Phenyl-2-[(2-Phenylpropane-2-yl) Peroxy] Propane "Product Name Park Mill D" (manufactured by NOF CORPORATION)
-2,5-di-methyl-2,5-di- (t-butylperoxyl) -hexyne-3
"Product name Perhexin 25B" (manufactured by NOF CORPORATION)

"Thermoplastic resin"
-Hydrogenated styrene-based thermoplastic resin "Product name Tough Tech H1041"
(Mw: 49,000, styrene unit content: 30% by mass, manufactured by Asahi Kasei Corporation)
-Hydrogenated styrene-based thermoplastic resin "Product name Tough Tech H1043"
(Mw: 39,000, styrene unit content: 67% by mass, manufactured by Asahi Kasei Corporation)
-Hydrogenated styrene-based thermoplastic resin "Product name Tough Tech N504"
(Mw: 200,000, styrene unit content: 32% by mass, manufactured by Asahi Kasei Corporation)
-Polystyrene "Product name PSJ-Polystyrene 685"
(PS Japan, Mw: 260,000)
・ Styrene-based thermoplastic resin "Product name Tough Prene A"
(Mw: 100,000, styrene unit content: 40% by mass, manufactured by Asahi Kasei Corporation)
-Hydrogenated styrene-based thermoplastic resin "Product name Tough Tech H1221"
(Mw: 60,000, styrene unit content: 12% by mass, manufactured by Asahi Kasei Corporation)

"Flame retardants"
・ Decabromodiphenylethane "Product name SAYTEX8010" (manufactured by Albemarle)

"filler"
・ Spherical silica (manufactured by Ryumori)

"Base material"
・ L glass cloth (manufactured by Asahi Schebel, style: 2116, boron: 7.3 parts by mass, permittivity: 4.9)
・ E glass cloth (manufactured by Asahi Schebel, style: 2116, boron: 2.1 parts by mass, permittivity: 6.8)

<Manufacturing example 1>
100 parts by mass of toluene was placed in a flask equipped with a stirrer and a stirrer. While controlling the internal temperature of the flask to 90 ° C., 40 parts by mass of PPE (“Zylon S203A” manufactured by Asahi Kasei Co., Ltd.) with a number average molecular weight of 12700, 2,4 ′, 4 ″ -trihydroxytriphenylmethane (2 parts by mass), excess. A solution of PPE having a reduced molecular weight was prepared by adding 8 parts by mass of benzoyl oxide and continuously stirring for 2 hours for reaction. The Mn of this PPE was 1800, the Mw / Mn was 2.3, and the average number of phenolic hydroxyl groups per molecule was 2.8. While maintaining the internal temperature at 90 ° C., 0.4 parts by mass of N, N'-dimethyl-4-aminopyridine was added and dissolved in this solution of PPE, and then 10 parts by mass of methacrylic anhydride was gradually added. The resulting solution was maintained at 90 ° C. for 3 hours with stirring. The solution was then cooled to room temperature to give a solution of PPE with the backbone end denatured to a methacrylic group. A precipitate of PPE was produced by gradually adding this solution to 300 parts by mass of isopropanol heated to 40 ° C. with stirring. The mixture was recovered by filtration, and the recovered precipitate was vacuum dried in a vacuum oven at 105 ° C. for 5 hours. The terminal methacrylic acid-modified PPE obtained by the above operation was designated as PPE-A. The Mn of PPE-A was 2150, and the average number of phenolic hydroxyl groups per molecule was 0. Therefore, the number of terminal functional groups (methacrylic groups) of PPE-A was 2.8.

<Manufacturing example 2>
A solution of PPE having a reduced molecular weight was obtained by the same method as in Production Example 1 except that the amount of benzoyle peroxide added was changed to 6 parts by mass. The Mn of this PPE was 2800, the Mw / Mn was 2.5, and the average number of phenolic hydroxyl groups per molecule was 2.9. Next, PPE (PPE-B) whose terminal was modified with a methacrylic group by the same method as in Production Example 1 except that the amount of dimethylaminopyridine added was changed to 0.3 parts by mass and the amount of methacrylic anhydride added was changed to 6 parts by mass. ) Was obtained. The Mn of PPE-B was 3240, and the average number of phenolic hydroxyl groups per molecule was 0. Therefore, the number of terminal functional groups (methacrylic groups) of PPE-B was 2.9.

<Manufacturing example 3>
A solution of PPE having a reduced molecular weight was obtained by the same method as in Production Example 1 except that the amount of benzoyle peroxide added was changed to 4 parts by mass. The Mn of this PPE was 3700, the Mw / Mn was 2.7, and the average number of phenolic hydroxyl groups per molecule was 2.9. Next, PPE (PPE-C) whose terminal was modified with a methacrylic group by the same method as in Production Example 1 except that the amount of dimethylaminopyridine added was changed to 0.2 parts by mass and the amount of methacrylic anhydride added was changed to 4 parts by mass. ) Was obtained. The Mn of PPE-C was 4250, and the average number of phenolic hydroxyl groups per molecule was 0. Therefore, the number of terminal functional groups (methacrylic groups) of PPE-C was 2.9.

<Example 1>
To 210 parts by mass of toluene, 9 parts by mass of Tough Tech H1041 was added, and the mixture was stirred and dissolved. Then, 24.5 parts by mass, 66 parts by mass, and 80 parts by mass of SAYTEX8010, spherical silica, and SA9000 were added, and stirring was continued until SA9000 was dissolved. Then, 20 parts by mass and 0.5 parts by mass of TAIC and perbutyl P were added, respectively, and the mixture was sufficiently stirred to obtain a varnish. After impregnating this varnish with L glass cloth (manufactured by Asahi Schebel Co., Ltd., style: 2116), excess varnish is scraped off by passing it through a predetermined slit, dried in a drying oven at 105 ° C. for a predetermined time, and toluene is used. Was removed to obtain a prepreg. The solid content of the resin composition in the prepreg was calculated by cutting the prepreg into a predetermined size and comparing the weight with the weight of the glass cloth having the same size, and it was 58% by mass. A predetermined number of these prepregs are stacked, and copper foil (manufactured by Furukawa Electric Co., Ltd., thickness 35 μm, GTS-MP foil) is laminated on both sides of the stacked prepregs, and then vacuum pressed to perform copper tensioning. A laminated board was obtained. In this vacuum press process, first, the pressure is set to 10 kg / cm ² while heating from room temperature at a heating rate of 3 ° C./min, and then after reaching 130 ° C., heating is performed at a heating rate of 3 ° C./min. However, the pressure was set to 40 kg / cm ² . After reaching 200 ° C., the conditions were set at a pressure of 40 kg / cm ² and a time of 60 minutes while maintaining the temperature at 200 ° C. Next, the copper foil was removed from the copper-clad laminate by etching to obtain a laminate.

<Examples 2 to 23, Comparative Examples 1 to 8>
Varnishes were prepared in the same manner as in Example 1 except that each material was used as shown in Tables 1 to 4. Further, a prepreg was prepared by the same method as in Example 1 to obtain a prepreg having a resin composition content of 58% by mass. Further, these prepregs were obtained by the same method as in Example 1 to obtain a copper-clad laminate and a laminate from which the copper foil was removed.

The characteristics of the copper-clad laminates and laminates of Examples 1 to 23 and Comparative Examples 1 to 8 were evaluated. The evaluation results are shown in Tables 5-8.

From the results in Tables 5 to 8, by using the resin composition according to the present invention, a laminated board having excellent heat resistance, dielectric constant, and dielectric loss tangent, and suppressing fluctuations in dielectric constant and dielectric loss tangent due to environmental changes. I was able to get.

The present invention is suitable, for example, as an insulating material for an electronic circuit board of an electronic device that utilizes a high frequency band.

Claims (9)

A prepreg containing a base material and a resin composition impregnated or coated on the base material.
The resin composition contains a polyphenylene ether, a cross-linking agent , an organic peroxide , and a thermoplastic resin .
The polyphenylene ether has the following formula (1): at the end of the main chain.

(In the formula (1), n represents 0 , R ¹ represents a saturated alkyl group or an unsaturated alkyl group having 1 to 8 carbon atoms, and R ² is a hydrogen atom or 1 to 8 carbon atoms. Indicates a saturated alkyl group or an unsaturated alkyl group having
Each molecule has an average of 1.5 to 5 functional groups represented by, and the number average molecular weight of the polyphenylene ether is 1000 or more and 4500 or less.
The cross-linking agent has an average of two or more carbon-carbon unsaturated double bonds in one molecule, and the number average molecular weight of the cross-linking agent is 4000 or less.
The weight ratio of the polyphenylene ether to the cross-linking agent is the former: the latter = 62: 38 to 95: 5.
The organic peroxide is the following formula (2) or (3):

In formula (2), R ³ and R ⁴ are monovalent hydrocarbon groups each independently having 1 to 15 carbon atoms, and at least one of R ³ and R ⁴ has an aromatic ring. In formula (3), R ⁵ and R ⁷ are monovalent hydrocarbon groups having 1 to 15 carbon atoms independently, and R ⁶ is a divalent hydrocarbon group having 1 to 15 carbon atoms. At least one selected from the group consisting of R ⁵ , R ⁶ , and R ⁷ which is a hydrocarbon group has an aromatic ring.)
It is an aromatic ring-containing dialkyl peroxide having a structure represented by.
The content of the organic peroxide is 0.05 parts by mass or more and 0.9 parts by mass or less with respect to 100 parts by mass in total of the polyphenylene ether and the cross-linking agent .
The thermoplastic resin is one or more selected from the group consisting of a block copolymer of a vinyl aromatic compound and an olefin-based alkene compound, a hydrogenated product thereof, and a homopolymer of the vinyl aromatic compound. The content of the unit derived from the vinyl aromatic compound of the block copolymer or its hydrogenated product is 20% by mass or more.
A prepreg in which the base material is glass cloth and the dielectric constant of the glass cloth is 5.1 or less. The prepreg according to claim 1, wherein the cross-linking agent contains at least one compound selected from the group consisting of triallyl cyanurate, triallyl isocyanurate, and polybutadiene. The prepreg according to claim 1 or 2, wherein the thermoplastic resin has a weight average molecular weight of 30,000 to 300,000. The prepreg according to any one of claims 1 to 3 , wherein the content of the thermoplastic resin is 2 to 20 parts by mass with respect to a total of 100 parts by mass of the polyphenylene ether and the cross-linking agent. The prepreg according to any one of claims 1 to 4 , which contains a flame retardant and the flame retardant is incompatible with the resin composition even after curing. The prepreg according to any one of claims 1 to 5 , further comprising a solvent. The prepreg according to any one of claims 1 to 6 , wherein the glass cloth contains 5.5 parts by mass or more and 8.5 parts by mass or less of boron with respect to 100 parts by mass of the glass cloth. .. A metal-clad laminate obtained by laminating and curing a prepreg according to any one of claims 1 to 7 and a metal foil. A printed wiring board according to claim 8 , wherein a part of the metal foil is removed from the metal-clad laminate.