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    3.
    发明专利
    未知

    公开(公告)号：DE1165269B

    公开(公告)日：1964-03-12

    申请号：DEB0068612

    申请日：1962-08-29

    Applicant: BASF AG

    Inventor： OHLINGER DR HELMUT ,  GUENTHER DR WOLFGANG ,  SINGLE DIPL-ING WINFRIED ,  BUCHHOLZ DR KARL ,  WILD DR HANS

    IPC: C08F279/02 ,  C08J9/16

    Abstract: Finely particled expandable styrene polymers are manufactured by a process wherein styrene or a mixture of monomers comprising styrene and one or more a -ethylenically unsaturated compounds which can be copolymerized with styrene, and an organic compound which is liquid or gaseous at standard pressure and temperature which does not dissolve or only swells the styrene polymer obtained by polymerization of styrene or the said mixture of monomers and which has a boiling point lower than the softening point of the styrene polymer, is continuously introduced at the top of a pressure vessel having a diameter less than its height, the styrene or the said mixture of monomers is polymerized with the temperature at the top of the pressure vessel being between 70 DEG C. and 130 DEG C. and at the bottom between 170 DEG C. and 230 DEG C. and the pressure in the pressure vessel being more than the vapour pressure of the organic compound and the monomers at the temperature prevailing at the bottom of the vessel, the composition comprising styrene polymer and organic compound is continually discharged at the bottom of the pressure vessel at a rate equivalent to that at which the monomers and organic compound are supplied at the top of the pressure vessel, and the composition is cooled to 20 DEG C. to 65 DEG C. and then reduced in size. The mixture of monomers should contain at least 50% by weight of styrene. A polymer of ethylenically unsaturated monomeric polymerizable compounds may also be added to the monomer mixture. In general the expanding agents have boiling points greater than - 45 DEG C., e.g. n-pentane, heptane, trichlorofluoroethane and trifluoro-1,1,2-trichloroethane. The ratio of diameter to height of the polymerization vessel may be between 1:100 and 1:5.

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