公开(公告)号：DE4438376A1

公开(公告)日：1996-05-02

申请号：DE4438376

申请日：1994-10-27

Applicant: BASF AG

Inventor： SCHERZER DIETRICH DR ,  HUSEMANN WOLFRAM DR ,  WITT MICHAEL DR ,  HAHN KLAUS DR ,  KAEMPFER KNUT DR ,  ALICKE GERHARD

IPC: C08F2/18 ,  C08F2/20 ,  C08F2/38 ,  C08F12/08 ,  C08F255/02 ,  C08F257/00 ,  C08F257/02 ,  C08J9/20 ,  C08J11/08 ,  C08L23/06 ,  C08L25/00 ,  C08L25/04 ,  C08L25/06 ,  C08J11/04 ,  C08L51/06

Abstract: Expandable polystyrene contains up to 40 wt.% recycled polystyrene. It is obtd. by dissolving the recycled material in styrene monomer and polymerising this soln. in aq. suspension, with addn. of finely-divided polyethylene wax (I) and/or a mol.wt. regulator (II) during polymerisation. Pref. the material is treated with 0.05-1.0 wt.% (I) and/or 10-5000 ppm (II). (I) has a Mn of 2000-6000. (II) is dimerised alpha -methylstyrene.

公开(公告)号：AT135387T

公开(公告)日：1996-03-15

申请号：AT93109565

申请日：1993-06-16

Applicant: BASF AG

Inventor： WITT MICHAEL DR ,  HAHN KLAUS DR ,  LORENZ MARIA DR

IPC: C08J9/18

Abstract: A process for the preparation of expandable thermoplastic polymers by post-impregnation with a blowing agent in liquid suspension in the presence of a mixture of magnesium pyrophosphate and a sulphonate group-containing extender as suspension stabiliser in a reactor, characterised in that a) the magnesium pyrophosphate is prepared in the same reactor at a temperature below 50 DEG C by addition of a solid magnesium salt in an amount corresponding to an at least 3% stoichiometric excess, based on pyrophosphate, to an aqueous solution of the pyrophosphate, b) the suspension medium is heated to a temperature in the range between 70 and 140 DEG C, and c) the blowing agent is added in this temperature range.