| 摘要 |
1494933 Cross-linking graft polymers HOECHST AG 26 June 1975 [28 June 1974] 27142/75 Heading C3G A graft polymer is produced by bulk or bulk/ suspension polymerization of a mixture of (a) styrene and/or a styrene derivative and acrylonitrile and/or another derivative of acrylic acid and (b) an ethylene/propylene/tercomponent rubber, an organic peroxide is added to the reaction mixture prior to or during polymerization and the graft polymer is subjected to a two-step extrusion, the first step being carried out at 130‹ to 240‹ C. to produce by shearing rubber particles of a size less than 1 micron and the second step being carried out at 200‹ to 280‹ C. to cross-link the rubber particles, the quantity, half-life and time of addition of the peroxide and the polymerization and shearing temperatures being chosen in a manner such that, after termination of shearing, the quantity of peroxide remaining in the polymer is from 0À05 to 0À5% by weight calculated on the total quantity of monomers and rubber. Examples are given in which styrene and acrylonitrile are grafted on to ethylene/ propylene/ethylidene norbornene rubber by a bulk-suspension process in which (i) di-t-butyl peroxide is used as initiator in the bulk stage, dibenzoyl peroxide is added prior to the suspension stage and the graft polymer is subjected to extrusion in a double screw extruder (1) at 180‹ C. and (2) at 230‹ to 250‹ C.; (ii) as (i) except that di-t-buty peroxide is also added prior to the suspension stage and the extrusion stage (1) is at 160‹ C.; (iii) at (i) except that stage (1) is at 200‹ C. and stage (2) at 220‹ to 240‹ C. and (iv) as (i) except that a mixture of dibenzoyl peroxide and t-butyl hydroperoxide is added prior to the suspension stage and stage (2) is at 240‹ C.
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