| 摘要 |
A powdery copolymer having a powder particle size from 0.1 to 200 microns, said copolymer comprising at least 50 percent by weight of methyl methacrylate and 0.2 to 10 percent by weight of at least one monomer having a basic nitrogen atom, the balance, if any, being other monomers copolymerizable therewith, said copolymer being prepared by emulsion copolymerization such that all or a predominant portion of the monomer or monomers having a basic nitrogen atom is first added to the remaining monomers after the polymerization of at least half of said remaining monomers, the resulting copolymer then being recovered from the resultant latex in powder form. |
