Abstract: A methyl methacrylate syrup composition comprises an intimate mixture of 1-99 parts by weight of a first polymer-in-monomer syrup (A) and 99-1 parts by weight of a second polymer-in-monomer syrup which can be either (B.sub.1) or (B.sub.2), wherein the syrups (A), (B.sub.1) and (B.sub.2) are as follows:(A) a polymer-in-monomer syrup obtained by copolymerizing a mixture of methyl methacrylate monomer, one or more monomers having reactivity with glycidyl groups and containing at least one ethylenically-unsaturated bond, and one or more of (meth)acrylates, styrene and styrene derivatives;(B.sub.1) a polymer-in-monomer syrup obtained by copolymerizing a mixture of one or more monomers containing at least one glycidyl group and at least one ethylenically-unsaturated bond, and one or more monomers selected from the group consisting of methyl methacrylate, (meth)acrylates, styrene and styrene derivatives;(B.sub.

Abstract: An abrasive for removing flashes of a molded product, which comprises synthetic resin particles, each particle having a plurality of cutting edges and of cracks capable of easily forming cleavages upon collision against a workpiece. A method for manufacturing such synthetic resin abrasive particles which comprises a step of intentionally forming a number of cracks in the resin particles.