| 摘要 |
A process for producing a shelf-stable ethylene- alpha -olefin (diene) elastomer powder which comprises a release agent, comprising grinding crumbs or preliminarily comminuted particles of an ethylene- alpha -olefin (diene) elastomer having a green strength of 5-20 MPa and a Mooney viscosity ML (1+4) 100 DEG C. of 50-150, and, prior to, during or after the grinding step, adding 0.5-10 parts by weight per 100 parts by weight of the ethylene- alpha -olefin (diene) elastomer, of a release agent which is (a) polyethylene of a density of 0.910-0.975 g/cm3, a viscosity number of 50-330 cm3/g and a melt index of 0.2-50 g/10 min, polypropylene of a density of 0.90-0.910 g/cm3, a viscosity number of 100-1000 cm3/g and a melt index of 0.1-50 g/10 min, polybutene-1 of a density of 0.910-0.975 g/cm3, a viscosity number of 100-1000 cm3/g and a melt index of 0.1-100 g/10 min, polyvinyl chloride of a viscosity number of 50-200, all having an average secondary particle size of 5-50 mu m; (b) a synthetic amorphous silicic acid (SiO2) having an average primary particle size of 0.01-0.2 mu m and an average secondary particle size of 5-35 mu m; a naturally occurring silicic acid, at least 65% by weight of which has an average primary particle diameter of <5 mu m and an average secondary particle size of 7-50 mu m; or a silicic-acid-containing mineral having an average primary particle size of 0.5-2.5 mu m and an average secondary particle size of 10-35 mu m; or (c) a carbon black with an average primary particle size of <0.3 mu m.
|
