Novel solid thermosetting resins and processes for preparing same

Claim 1

A process for the preparation of a solid graft copolymeric thermosetting resin comprising: reacting liquid 1,2-polybutadiene glycol with a diisocyanate chain extender in an organic solvent solution, in a molar ratio of 2/3 to 9/10 mole of diisocyanate per mole of hydroxy groups in said gylcol, to produce a urethanated prepolymer substrate; adding glycidyl methacrylate to a solvent solution of said urethanated prepolymer in a ratio of 0.04 to 0.48 mole of said glycidyl methacrylate per mole of pendant vinyl groups in said prepolymer and a free radical polymerization initiator to form a first stage reaction mixture; reacting said first stage mixture until 55 to 65 weight % of the glycidyl methacrylate added has reacted with the prepolymer; and then adding a second polymerizable monomer to said first stage reaction mixture and reacting same to obtain a graft copolymeric thermosetting resin containing 0.35 to 1.1 moles total of glycidyl methacrylate and second monomer per mole of pendant vinyl groups in the prepolymer substrate, said second monomer being a monomer different from said glycidyl methacrylate.