A thermosetting resin composition, a prepreg, a laminate, and a printed circuit board are provided. The thermosetting resin composition has a thermosetting polyphenylene ether resin, an unsaturated polyolefin resin, a curing agent, and hollow borosilicate microspheres with surfaces treated with a bromine-containing silane coupling agent. The laminate produced from the thermosetting resin composition satisfies the requirements for overall properties such as low dielectric constant, low dielectric loss, low water absorption rate, high peeling strength, and the like for a high-frequency electronic circuit substrate.

An emulsifier-free process for the preparation of water expandable polymer beads, including: a) providing an emulsifier-free starting composition comprising styrene, b) prepolymerizing the starting composition to obtain a prepolymer composition, c) mixing an aqueous blowing agent with the prepolymer composition at an elevated temperature to obtain an inverse emulsion of water droplets in the prepolymer composition, wherein the aqueous blowing agent comprises water and a water soluble initiator dissolved in the water and the water droplets comprise spheres of a styrene polymer, wherein the water soluble initiator partly decomposes due to the elevated temperature leading to the formation of the inverse emulsion of water droplets in the prepolymer composition, d) suspending the inverse emulsion in an aqueous medium to yield an aqueous suspension of suspended droplets and e) polymerizing monomers in the droplets of the suspension obtained by step d) to obtain the water expandable polymer beads.

A resin composition is provided. The resin composition comprises: (A) a compound having a structure of formula (I), ##STR00001## wherein R.sub.1 is an organic group; and (B) a vinyl-containing elastomer, wherein the weight ratio of the compound having the structure of formula (I) to the vinyl-containing elastomer is 20:1 to 1:1.

A curable composition includes specific amounts of a ketone, a curable component, and particulate poly(phenylene ether) having a mean particle size of 3 to 12 micrometers and a particle size relative standard deviation of 20 to 60 percent. The composition has a low viscosity that facilitates wetting of reinforcing structures, and composites formed from the composition and a reinforcing structure cure to form a dielectric material with a low dielectric constant and loss tangent.

A prepreg containing at least the following components [A]-[F], wherein the ratio Ne/Nd of the number of structures Ne of component [F] present in a range of outside 110% of the particle diameter of component [E] and the number of structures Nd of component [F] present in a range outside 110% of the particle diameter of component [D] is 0.25 or higher. [A]: Carbon fibers, [B] thermosetting resin, [C]: curing agent, [D]: particles composed mainly of thermoplastic resin having a primary particle number-average particle size of 5-50 μm, [E]: conductive particles different from component [D] and having a primary particle number-average particle size in the range of a specific expression, [F]: filler comprising a carbon material.

A thermosetting resin composition and a prepreg and a laminated board prepared therefrom. The thermosetting resin composition contains the following components in parts by weight: 50-150 parts of a cyanate; 30-100 parts of an epoxy resin; 5-70 parts of styrene-maleic anhydride; 20-100 parts of a polyphenyl ether; 30-100 parts of a halogen-free flame retardant; 0.05-5 parts of a curing accelerator; and 50-200 parts of a filler. The prepreg and laminated board prepared from the thermosetting resin composition have comprehensive performances such as a low dielectric constant, a low dielectric loss, an excellent flame retardance, heat resistance and moisture resistance, etc., and are suitable for use in a halogen-free high-frequency multilayer circuit board.

Provided is a resin composition, a prepreg for a printed circuit and a metal-coated laminate. The resin composition includes: a silicone aryne resin, a polyphenylene ether resin with unsaturated bonds, and a butadiene polymer. The resin composition is used such that the prepared metal-coated laminate can have at least one of the following characteristics: a low dielectric loss factor, high heat resistance, and a low coefficient of thermal expansion.

A filler-containing film has a structure in which fillers are held in a binder resin layer. The average particle diameter of the fillers is 1 to 50 μm, the total thickness of the resin layer is 0.5 times or more and 2 times or less the average particle diameter of the fillers, and the ratio Lq/Lp of, relative to the minimum inter-filler distance Lp at one end of the filler-containing film in a long-side direction, a minimum inter-filler distance Lq at the other end at least 5 m away from the one end in the film long-side direction is 1.2 or less. The fillers are preferably arranged in a lattice form.

A resin composition is provided and includes (A) a modified polyphenylene ether compound terminal-modified with a substituent having a carbon-carbon unsaturated double bond, (B) a maleimide compound containing no phenylmaleimide group and having a hydrocarbon group having 10 or more carbon atoms in the molecule thereof, and (C) at least one selected from a maleimide compound containing a phenylmaleimide group and a maleimide compound having an aliphatic hydrocarbon group having 9 or less carbon atoms in the molecule thereof, in which the content ratio of the component (A) to the component (B) is (A):(B)=20:80 to 90:10 in mass ratio.

This resin composition contains a first resin and a second resin, and exhibits curability by thermal crosslinking, wherein the first resin is at least one selected from among a bifunctional epoxy resin having a weight average molecular weight of 4,000 or more, and a phenoxy resin, and the second resin is a polycarbonate resin. The content ratio, by weight, of the first resin to the second resin (the first resin:the second resin) is preferably in the range of 9:1 to 2:8. Both the first resin and the second resin preferably have a bisphenol skeleton in a molecule.