| 摘要 |
<p>1439020 Polyethylene compositions RUHRCHEMIE AG 10 Sept 1973 [16 Sept 1972] 42393/73 Heading C3P Compositions having high wear resistance comprise a low pressure polyethylene having a viscosimetrically determined molecular weight above 1,000,000 and homogeneously distributed therein 0À2 to 0À6 per cent by weight of a compatible organic peroxide prepressed at a pressure of at least 50 kp/cm.<SP>2</SP> and plasticized at a temperature of at least 190‹ C. and a pressure of at least 50 kp/cm.<SP>2</SP>. The peroxide may be a phthalide peroxide and may be supported on an inert carrier, e.g. silica. It may be mixed with a portion of the polyethylene to form a concentrate which is dispersed in further polyethylene. The compositions may be extrusion moulded or ram extruded to form wear resistant profiles. In examples polyethylene mixed with calcium stearate and dilauryl thiodipropionate are mixed with silica-supported (1,3 and 4) 3-methyl-3-t-butylperoxyphthalide, (2) dicumyl peroxide, (5) 3-ethyl-3-t-butylperoxyphthalide, (6) 3-p-chlorophenyl-3-t-butylperoxyphthalide, (7) 3-methyl-3-t-amylperoxyphthalide, (8) 1,3-bis-(t-butylperoxyisopropyl)benzene and (9) 2,5-dimethyl-2,5-di-t-butylperoxyhexane.</p> |
