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    EXPANDABLE STYRENE POLYMER BEADS CONTAINING STERICALLY HINDERED PHENOLS AND THEIR PRODUCTION
    16.
    发明专利
    EXPANDABLE STYRENE POLYMER BEADS CONTAINING STERICALLY HINDERED PHENOLS AND THEIR PRODUCTION 未知

    公开(公告)号：CA2171867A1

    公开(公告)日：1995-03-30

    申请号：CA2171867

    申请日：1994-09-07

    Applicant: BASF AG

    Inventor： SCHERZER DIETRICH ,  RIETHUES MICHAEL ,  HENN ROLF ,  HAHN KLAUS ,  WITT MICHAEL

    IPC: C08J9/16 ,  C08F2/18 ,  C08F2/44 ,  C08J9/20 ,  C08K5/134 ,  C08L25/04 ,  C08J9/224

    Abstract: Pearl-shaped, expandable styrene polymers contain (a) a styrene polymer; (b) 0.03 to 1.5 % by weight, in relation to (a), of a sterically inhibited phenol homogenously distributed in the styrene polymer and/or applied as a coating on the surface of the styrene polymer; (c) an expanding agent or mixture of expanding agents; and if required (d) effective amounts of usual additives. Also disclosed is a process for producing said polymers, according to which styrene, if required with other comonomers, is polymerised in an aqueous suspension in the presence of suspension stabilisers and usual styrene-soluble polymerisation catalysts, with addition of an expanding agent or mixture of expanding agents, and if required of an effective amount of usual additives and of up to 1.5 % by weight, in relation to styrene and comonomers, of sterically hindered phenols. The thus obtained pearl-shaped, expandable styrene polymers are coated with up to 1.5 % by weight, in relation to the expanding agent-free styrene polymer, of sterically inhibited phenols, provided that the expandable styrene polymers that are homogenously distributed in the styrene polymer and/or applied as a surface coating contain in total 0.03 to 1.5 % by weight of sterically inhibited phenols, in relation to the styrene polymer.

    PREPARATION OF BEAD-FORM EXPANDABLE STYRENE POLYMERS HAVING IMPROVED EXPANDABILITY
    17.
    发明专利
    PREPARATION OF BEAD-FORM EXPANDABLE STYRENE POLYMERS HAVING IMPROVED EXPANDABILITY 未知

    公开(公告)号：CA2155423A1

    公开(公告)日：1994-09-29

    申请号：CA2155423

    申请日：1994-03-05

    Applicant: BASF AG

    Inventor： WITT MICHAEL ,  SCHERZER DIETRICH ,  HAHN KLAUS ,  NAEGELE DIETER

    IPC: C08F2/20 ,  C08F2/44 ,  C08J9/20 ,  C08K5/09

    Abstract: The invention concerns a method of producing expandable styrene-polymer spheres by polymerizing styrene, optionally using other comonomers, in aqueous suspension in the presence of organic-molecule colloids as suspension stabilizers and the usual styrene-soluble polymerization catalysts, and with the addition of a propellant and optionally other additives in effective amounts, the aqueous suspension containing at least one olefinically unsaturated carboxylic acid, or a water-soluble salt thereof, present in a amount, relative to the organic compounds present, of 0.002 to 0.3 % by wt. of carboxylic-acid anions.

    Preparation of expandable thermoplastic polymers by post-impregnation
    19.
    发明专利
    Preparation of expandable thermoplastic polymers by post-impregnation 未知

    公开(公告)号：AU4133893A

    公开(公告)日：1993-12-23

    申请号：AU4133893

    申请日：1993-06-18

    Applicant: BASF AG

    Inventor： WITT MICHAEL ,  HAHN KLAUS ,  LORENZ MARIA

    IPC: C08J9/18 ,  C08J9/20 ,  C08K13/02

    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.

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