Abstract: A composite-forming process includes impregnating a reinforcing structure with a curable composition at a temperature of about 10 to about 40° C. The curable composition includes specific amounts of an epoxy resin, a poly(arylene ether), a solvent, and a curing promoter. The poly(arylene ether) includes, on average, about 1.6 to about 2.4 phenolic hydroxy groups per molecule, and it has a polydispersity index less than or equal to 2.2 and an intrinsic viscosity of about 0.03 to about 0.2 deciliter per gram. These characteristics substantially improve the solubility of the poly(arylene ether) in the curable composition and allow the curable composition to be formed and used at or near room temperature. Composites formed by the process and circuit boards including the composites are also described.

Abstract: A curable composition includes a functionalized poly(arylene ether), a vinyl thermoset resin, and a flame retardant composition. The flame retardant composition includes a trihydrocarbylphosphine oxide and a nitrogen-containing flame retardant that may be melamine phosphate, melamine pyrophosphate, or melamine polyphosphate. The combination of the trihydrocarbylphosphine oxide and the nitrogen-containing flame retardant is particularly effective at improving the flame retardancy of the cured composition at relatively low levels of total flame retardant. A method of preparing the curable composition and articles including the cured composition are also described.

Abstract: A varnish composition for producing an electrically insulative thermoset coating is provided. The varnish composition includes poly(phenylene ether) having at least one end group having aliphatic unsaturation and a reactive solvent. When cured, the poly(phenylene ether) and reactive solvent form an electrically insulative thermoset.