发明名称 |
Processes for preparing vinyl chloride polymers. |
摘要 |
<p>Vinyl chloride polymer is prepared by suspension polymerization of monomeric vinyl chloride or a mixture of vinyl chloride and another monomer in an aqueous medium while agitating the suspension. A first partially saponified polyvinyl alcohol having a degree of saponification of 60 - 80 mol% and an average degree of polymerization of 500-1,000 is added as a suspension stabilizer at the start of polymerization, and a second partially saponified polyvinyl alcohol having a degree of saponification of 75 - 85 mol% and an average degree of polymerization of 1,500-2,700 is added while the conversion is 30% to 60%. The agitating power is controlled to 80 - 120 kg.m/s.ton from the start of polymerization to a conversion of 20 to 50%, and to 130-200 kg.m/s.ton from then to the completion of polymerization. The resulting vinyl chloride polymer is of quality as demonstrated by a high bulk density and improved free flow, monomer removal, gelation, and plasticizer absorption as well as minimal fish eye. Scale build-up on the reactor wall is minimized.</p> |
申请公布号 |
EP0623632(A2) |
申请公布日期 |
1994.11.09 |
申请号 |
EP19940303257 |
申请日期 |
1994.05.05 |
申请人 |
SHIN-ETSU CHEMICAL CO., LTD. |
发明人 |
AMANO, TADASHI;HIYAMA, TADAYOSHI, 3-208, SHIN-ETSU CHEMICAL |
分类号 |
C08F2/20;C08F14/06;(IPC1-7):C08F14/06 |
主分类号 |
C08F2/20 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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