| 摘要 |
Amorphous, chlorinated ethylene polymers which have relatively low blocking tendencies in the absence of antiblock additives are prepared in a multi-step process. The process involves reacting porous, solid, finely divided, high density polyethylene particles with gaseous chlorine in the presence of a free radical initiator while said particles are agitated or maintained in a fluidized bed state. In a first step, addition of gaseous chlorine is started while the agitated particles are at a temperature of less than about 50 DEG Centigrade. Little, if any, chlorination takes place in the first step. In a second step, the agitated particles are chlorinated to a level of from about 5 to about 14 percent while the temperature of said particles is increased to a temperature within a temperature range of from about 50 DEG Centrigrade to about 105 DEG Centigrade. Chlorination of the agitated particles is continued in a third step wherein the temperature of said particles is increased at a certain rate up to a temperature of from about 125 DEG Centigrade to about 132 DEG Centigrade. Chlorination of the agitated particles is completed in a fourth step while the temperature of said particles is increased to a temperature in excess of about 130 DEG Centigrade but less than that temperature at which the particles tend to agglomerate. The fourth step is continued until a percent residual relative crystallinity of less than about 2 percent is obtained and a desired chlorine content is achieved. Illustrative chlorine contents are from about 30 to about 42 percent by weight of chlorinated polymer. |
