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    2.
    发明专利
    未知

    公开(公告)号：DE2212962A1

    公开(公告)日：1973-09-20

    申请号：DE2212962

    申请日：1972-03-17

    Applicant: BASF AG

    Inventor： DEUSCHEL WALTER DR ,  GULBINS ERICH DR ,  HAUSS ALFRED DR ,  LAUSBERG DIETRICH DR ,  SIGMUND WILHELM DR

    IPC: C08F14/00 ,  C08F2/00 ,  C08F2/18 ,  C08F14/06 ,  C08F3/30

    Abstract: 1414714 Suspension polymerization BADISCHE ANILIN- & SODA-FABRIK AG 16 March 1973 [17 March 1972] 12765/73 Heading C3P In the polymerization of vinyl chloride, optionally with up to 30% by weight of one or more comonomers, in aqueous suspension in the presence of a free-radical initiator and a watersoluble protective colloid in a stirred reactor, the polymerization mixture is heated to the desired polymerization temperature in a heat-up stage which constitutes not more than one third of the time required for the full polymerization cycle, whereupon polymerization is carried out in a polymerization stage at a substantially constant temperature, while (a) using one or more free-radical initiators having a half-life at 50‹ C. of less than 10 hours, (b) maintaining the polymerization mixture at a pH of less than 8 during the heat-up stage, and (c) maintaining the temperature of the reactor walls at not more than 20‹ C. above the temperature of the polymerization mixture during the heat-up stage and maintaining the temperature of the reactor walls at a lower value than that of the polymerization mixture during the polymerization stage. At least 30% of the monomers are grafted on to the protective colloid in the heat up stage.

    Removing residual monomers etc. from aq. polymer dispersions - by passing through the dispersion a stream of inert gas contg. specified vol. of water to gas
    6.
    发明专利
    Removing residual monomers etc. from aq. polymer dispersions - by passing through the dispersion a stream of inert gas contg. specified vol. of water to gas 未知

    公开(公告)号：DE4118526A1

    公开(公告)日：1991-12-19

    申请号：DE4118526

    申请日：1991-06-06

    Applicant: BASF AG

    Inventor： DEUSCHEL WALTER DR ,  LAY PETER N ,  WAGNER KURT JOSEF

    IPC: C08F6/00

    Abstract: Process is claimed for removing residual monomers and low-mol wt. impurities (I) from polymers in aq. dispersion by passing through the dispersion a stream of gas produced by means of a distributor device, the novelty is that the gas stream contains 0.01-0.5-1 liq. water per 100-1 gas. The process can be used with aq. dispersions (pref. 40-60 wt. %) of various polymers (based on styrene, olefins, dienes, acrylonitrile, acrylate, vinyl ethers, etc. contg. up to 1500 ppm (I), pref. the dispersion is treated at 70-80 deg.C with a stream of gas (nitrogen, air, etc) contg. water at 10-30 deg.C then worked up e.g. by spray drying. USE/ADVANTAGE - The process enables the removal of (I) from polymer dispersions without the disadvantages of prior art processes (high cost of steam treatment, breakdown of dispersions, coagulation).

    Process for the preparation of vinyl chloride polymers
    9.
    发明专利
    Process for the preparation of vinyl chloride polymers 未知

    公开(公告)号：DE3633818A1

    公开(公告)日：1988-04-14

    申请号：DE3633818

    申请日：1986-10-04

    Applicant: BASF AG

    Inventor： DEUSCHEL WALTER DR ,  HEBGEN WERNER DR

    IPC: C08F2/20 ,  C08F14/06

    Abstract: The preparation of vinyl chloride polymers by polymerisation of vinyl chloride or a mixture of vinyl chloride and one or more other monomers which can be copolymerized with vinyl chloride, with stirring in aqueous suspension, by free-radical polymerisation in the presence of protective colloids, where the polymerisation is terminated after from 70 to 97 % of the polymerisation time to be expected before the pressure drops.

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