| 摘要 |
<p>1536208 Polyvinyl chloride; anti-scaling agents SHIN-ETSU CHEMICAL CO Ltd 11 March 1976 [24 March 1975 31 March 1975] 09696/76 Heading C3P [Also in Division B1] In a polymerization vessel employed for the bulk polymerization of vinyl chloride, either alone or with comonomers, the inner walls and other surfaces which contact the polymerization system are precoated with a compound having a solubility of >0À5 g. per 100 g. of H 2 O at 25‹ C. and a boiling point of >60‹C/ 760 mm. Specified classes of compound are (i) alkali metal (A.M.) or alkaline earth metal hydroxides, (ii) metal-containing acids, or A.M. salts thereof, (iii) phosphorus-containing acids, (iv) A.M. carbonates, phosphates, polymetaphosphates or polyphosphates, (v) sulphates, nitrates, halides, and double salts thereof, of metallic elements other than those of V, Nb, and Ta, (vi) A.M. thiocyanates, ferrocyanides and ferricyanides, and double salts thereof, (vii) A.M. borates and silicates, and boric acid and (viii) a wide range of polymeric and non- polymeric organic compounds.</p> |
