One aspect of the present application relates to a resin composition including a modified polyphenylene ether compound having a carbon-carbon unsaturated double bond at a molecular end, a maleimide compound having two or more N-substituted maleimide groups in one molecule, and a liquid styrene-butadiene copolymer having a weight average molecular weight of less than 10000 and having a 1,2-vinyl group.

Provided are a metal-clad laminate, a printed circuit board, and a semiconductor package, wherein the warps therein are effectively suppressed. Specifically the metal-clad laminate comprises a prepreg, wherein the prepreg has a resin composition attached to a fiber base material and satisfies a following formula (1) as well as a Mowing formula (2), provided that in the formulae, a1 represents an average thickness of the resin composition after being cured which is present on one surface of the fiber base material; a2 represents an average thickness of the resin composition after being cured which is present on other surface of the fiber base material; and B represents an average thickness of the fiber base material.
0.12<{(a1+a2)/2}/B  (1)
0.8≤a1/a2≤1.25  (2)

[Problem] Provided is a resin composition, resin sheet, prepreg and printed wiring board capable of obtaining excellent low permittivity, low dielectric loss tangent, flexibility and peel strength.

[Solution Means] A resin composition containing (A) a maleimide compound exhibiting a relative permittivity of lower than 2.7, (B) a polyphenylene ether compound represented by general formula (1) below and having a number-average molecular weight of 1000 to 7000, and (C) a block copolymer with a styrene skeleton. In general formula (1), X represents an aryl group, —(Y—O)n.sub.2- represents a polyphenylene ether portion, R.sub.1, R.sub.2 and R.sub.3 each independently represent a hydrogen atom or an alkyl, alkenyl or alkynyl group, n.sub.2 represents an integer of 1 to 100, n.sub.1 represents an integer of 1 to 6 and n.sub.3 represents an integer of 1 to 4.

##STR00001##

To provide an epoxy resin composition that exhibits excellent low-dielectric properties and that is excellent in copper foil peel strength and interlayer cohesion strength in a printed-wiring board application, as well as an active ester resin that provides the epoxy resin composition. An active ester resin having a polyaryloxy unit containing a dicyclopentenyl group and represented by the following formula (1), and a polyarylcarbonyl unit. Here, R.sup.1 represents a hydrocarbon group having 1 to 8 carbon atoms, R.sup.2 represents a hydrogen atom, or formula (1a) or formula (1b), and at least one R.sup.2 is formula (1a) or formula (1b); and n represents a number of repetitions of 1 to 5.

##STR00001##

Provided is a resin composition having excellent low water absorption, as well as a cured product, a prepreg, a metal foil-clad laminate, a resin sheet, and a printed wiring board. The resin composition contains a compound (A) represented by Formula (M1) and a compound (B) containing two or more unsaturated carbon-carbon double bonds, and in Formula (M1), A is a four- to six-membered alicyclic group:

##STR00001##

A resin composition includes: (A) 100 parts by weight of a thermosetting resin, which includes a vinyl-containing polyphenylene ether resin, a maleimide resin, or a combination thereof; (B) 15 parts by weight to 50 parts by weight of a sintered body formed by aluminum nitride and boron nitride; and (C) 180 parts by weight to 280 parts by weight of titanium dioxide. Moreover, an article may be made from the resin composition, including a prepreg, a resin film, a laminate or a printed circuit board.

A resin composition includes 100 parts by weight of an unsaturated C═C double bond-containing polyphenylene ether resin and 20 parts by weight to 150 parts by weight of a homopolymer of Formula (1). The resin composition is useful for making different articles, including a prepreg, a resin film, a laminate or a printed circuit board, which may achieve excellent multi-layer board thermal resistance, thermal resistance after moisture absorption and rigidity and achieve high glass transition temperature, low dissipation factor, and low Z-axis ratio of thermal expansion.

##STR00001##

A resin composition includes 100 parts by weight of a prepolymer and 100 parts by weight to 250 parts by weight of a spherical silica prepared by vaporized metal combustion, wherein: the prepolymer is prepared by subjecting a reaction mixture to a prepolymerization reaction; the reaction mixture includes a maleimide resin, an amino-modified silicone and cyclohexanone, and relative to a total of 100 parts by weight of the maleimide resin, the amino-modified silicone and the cyclohexanone, the reaction mixture includes 60 parts by weight to 80 parts by weight of the maleimide resin, 15 parts by weight to 30 parts by weight of the amino-modified silicone and 2 parts by weight to 15 parts by weight of the cyclohexanone; the reaction mixture does not include m-aminophenol or p-aminophenol; and the amino-modified silicone has an amino equivalent of 750 g/mol to 2500 g/mol. The resin composition may be used to make various articles, such as a prepreg, a resin film, a laminate or a printed circuit board, and at least one of the following improvements can be achieved, including varnish transparency, varnish sedimentation property, glass transition temperature, X-axis coefficient of thermal expansion, T300 thermal resistance, resin cluster and resin filling property.

A first composition is disclosed that includes a fire-resistant thermoplastic resin. The fire-resistant thermoplastic resin includes 1-20 wt % of an aryl phosphate, includes 1-20 wt % of a phosphate polymer, and 60%-98% of a (meth)acrylic polymer, including units from at least one monomer, wherein the monomer is chosen from methyl methacrylate, acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, acrylonitrile and maleic anhydride. The first composition may further include a fabric or a composite material that is embedded with the fire-resistant thermoplastic resin. In some instances, the aryl-phosphate and the phosphonate polymer synergistically reduce an effective heat of combustion, a peak heat release, or a flame time as compared to a second composition that contains only one of the aryl phosphate or the phosphonate polymer.

A resin composition includes: a resin as Component (A); and an inorganic filler as Component (B). The Component (B) includes anhydrous magnesium carbonate as Component (b1) and aluminum oxide as Component (b2). Content of the Component (b1) falls within a range from 35% by volume to 65% by volume relative to 100% by volume of the Components (b1) and (b2) combined. Content of the Component (B) falls within a range from 60% by volume to 75% by volume relative to 100% by volume of the resin composition.