Patent GB-1475715-A (GB)
Title: Thermoplastic composition
IPC: C08L33/02
Filed: 1974-08-29
Abstract: 1475715 Thermoplastic compositions HOECHST AG 29 Aug 1974 37862/74 Heading C3P A thermoplastic composition comprises a mixture of (a) from 98 to 50 weight per cent of vinyl chloride polymer, namely either homopolymer or copolymer containing not more than 20 weight per cent of units derived from monomer(s) other than vinyl chloride, for example selected from vinyl acetate, acrylic acid esters and methacrylic acid esters, and (b) from 2 to 50 weight per cent of chlorinated low pressure polyethylene which has a chlorine content of from 25 to 42 weight per cent and which has been prepared by chlorination of low pressure polyethylene at a temperature of from 50 to 130 C. with the proviso that at least 10 weight per cent of the chlorine has been incorporated at a temperature of from 120 to 130 C, the chlorination having been effected in water in the presence of (i) from 0À1to 2 weight per cent, based on the polyethylene, of silicic acid and (ii) from 0À01 to 1 weight per cent, based on the polyethylene, of siloxane oil containing from 10 to 10,000 recurring units having the structure wherein each of R 1  and R 2  is an alkyl group preferably containing from 1 to 6 carbon atoms, an aralkyl group preferably containing from 7 to 12 carbon atoms or an aryl group, for example a phenyl group. The silicic acid, which preferably has an internal (BET) surface area of from 50 to 400 m.2/g. and an average particle size of from 1 to 50 microns, may be any known hydrous or anhydrous form of porous silica. The siloxane oil, which preferably has a viscosity at 25 C. of from 100 to 500,000 centistokes, may be a dimethyl-, diethyl-, dipropyl-, dibutyl-, dihexyl-, dioctyl-, didodecyl-, methylethyl- or methylpropyl-polysiloxane. Prior to being chlorinated, the polyethylene may have been thermally treated or pre-sintered at a temperature of from 100 C. to its crystallite melting point. The composition additionally may contain material selected from vinyl chloride polymer stabilizers, for example barium laurate, cadmium laurate, tin and lead compounds, organic phosphites and epoxide stabilizers, UV absorbers, lubricants, processing auxiliaries, dyes and pigments. The composition, which may be prepared by dry blending, may be used for making tubes, profiles, plates, sheets, cables and injection moulded articles. As exemplified, a mixture of suspension polyvinyl chloride having a K value of 70 and chlorinated polyethylene prepared by chlorination of polyethylene in water in the presence of silicic acid and either dimethylpolysiloxane (Examples 1 and 2) or an unidentified siloxane oil (Example 3) was rolled, together with barium/cadmium stabilizer and diphenyloctyl phosphite, for 10 minutes at 175 C. and the resulting blend was moulded into plates; and polyvinyl chloride having a K value of 70, chlorinated polyethylene prepared by chlorination of polyethylene in water in the presence of silicic acid and dimethylpolysiloxane, barium/cadmium laurate, diphenyloctyl phosphite, epoxidized soybean oil and titanium dioxide were mixed together in an impeller and the resulting blend was processed on a screw extruder at temperature rising from 150 to 180 C. to give ribbon having a glossy surface. Reference is made to Specification 1,475,716.