公开(公告)号：DE2719905A1

公开(公告)日：1978-11-16

申请号：DE2719905

申请日：1977-05-04

Applicant: BASF AG

Inventor： HINSELMANN KLAUS DIPL ING ,  WEBER HEINZ DIPL CHEM DR ,  BLECKMANN GERHARD ING GRAD ,  WINKENS HELMUT

IPC: B29C44/50 ,  C08J3/24 ,  C08J9/34 ,  B29D27/00

Abstract: Parent Patent discloses the continuous prepn. of foamed profiles, having thickness 1-200 mm, by (A) homogenising a mixt. contg. (a) an olefin polymer, (b) 1-30 wt. % solid organic blowing agent, decomposing on heating to generate inorganic gases, (c) 0.1-10 wt. % organic peroxide and opt. (d) 0.1-10 wt. % foaming auxiliaries, crosslinking promoters and standard additives; (B) crosslinking and foaming the olefin polymer in a foaming zone, at 160-280 degrees C; and (C) extruding the foam from foaming zone, with cooling and solidifying. In foaming zone, pressure is 5-150 bar. Ratio of foaming zone length: max. thickness is 100-2000:1. The improvement comprises applying an additional organic peroxide, c', to the surface of the homogenised mixt. of (A) before entering into foaming zone. c' is pref present at 0.001-0.1 wt. % w.r.t. (a+b+c+d)mixt. Peroxide c' is pref. added together with a lubricant, opt. contg. a solubiliser, e.g. a lower alcohol, for c'. The stronger outer skin allows the prepn. of extrudable foamed profiles having a lower gel content, e.g. 10-30 wt. %.