The Dow Chemical Company

Loyd B Hutchinson

Robert R Blanchard

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.degree. 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.degree. Centrigrade to about 105.degree. 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.degree. Centigrade to about 132.degree. 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.degree. 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.

Anhydrous process for preparing amorphous chlorinated polyethylene and

Process and apparatus for extruding synthetic resinous thermoplastic materials, wherein a heat plastified stream of such material is divided into a primary or core stream, and non-primary or secondary stream(s), the secondary stream(s) heated to a temperature substantially hotter than the core stream, and the hot secondary stream(s) thereafter layered onto the opposite surfaces of the core stream prior to expelling the material from an extrusion die. Such a process and apparatus is practiced to avoid a loss of surface smoothness in the extruded product.

Growing community of inventors

Denham Springs, LA, United States of America

Loyd B Hutchinson