| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polymer which is excellent in impact characteristics, esp. in thin-wall impact characteristics, without detriment to the balance among physical properties by mixing and grafting a part of a monomer component contg. an arom. vinyl monomer and a vinyl cyanide monomer, in a specified amt., with and onto a rubbery polymer before the addition of a polymn. initiator. SOLUTION: In polymerizing 25-55 pts.wt. monomer component comprising 50-99 wt.% arom. vinyl monomer, 1-50 wt.% vinyl cyanide monomer, and 0-50 wt.% other vinyl monomer in the presence of 45-75 pts.wt. rubbery polymer, a part of the monomer component is mixed in advance before the addition of a polymn. initiator in such a manner that the ratio of the amt. (m pts.wt.) of the monomer component mixed to the amt. (r pts.wt.) of the rubbery polymer charged is 0.2 or higher and the rest of the monomer component is added to the polymn. system in such an amt. that the ratio of the amt. (m' pts.wt.) of the monomer component charged from the begining until the end of the addition of the polymn. initiator to that of the total amt. (R pts.wt.) of the rubbery polymer charged until the end of the addition of the polymn. initiator is 0.2 or higher.
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