Abstract: An epoxy resinous composition suitable for impregnating windings of turbine generators comprises a reaction product of an epoxy resin and maleic anhydride combined with a vinyl monomer, a (vinyl or isopropenyl)phenyl glycidyl ether which co-reacts with the epoxy diester prepolymer formed from said reaction product, and the polymerized vinyl monomer, and an anhydride.

Abstract: A dry, highly flexible, porous, essentially solvent free mica insulation tape is made, containing a curable, resinous, bonding composition containing polybutadiene containing from 70 weight percent to 100 weight percent of 1,2-polybutadiene, and catalyst, where the tape contains from 2 weight percent to 15 weight percent of polybutadiene based on the total weight of the resin bonded tape, and where the tape is capable of subsequent impregnation by an impregnating resin.

Abstract: Disclosed is a coil of insulated wire impregnated with a solventless vacuum pressure impregnated resin. The resin contains polybutadiene, at least 15% of which is 1,2-polybutadiene, about 10 about 150 phr dicyclopentadiene acrylate, about 0.005 to about 0.75 phr of a free radial polymerization inhibitor, about 0.05 to about 2.5 phr of a free radial polymerization initiator, and up to about 2.0 phr of a coupling agent. An optional component is about 1 to about 80 phr of an aromatic monomer having 1 to 2 vinyl groups. Also disclosed is a method of making a vacuum pressure impregnated coil by placing a coil of insulated wire in a partial vacuum, impregnating the coil with the resin, applying pressure to the resin to force it into the interstices of the coil, and curing the resin by heating it at about 100.degree. to about 180.degree. C. for about 2 to about 16 hours.