63.
    发明专利
    未知

    公开(公告)号:DK67175A

    公开(公告)日:1975-10-27

    申请号:DK67175

    申请日:1975-02-21

    Applicant: HOECHST AG

    Abstract: Oxymethylene copolymer having heat and hydrolysis resistant terminal groups is prepared by heating the polymers present in a liquid phase, whereby a thermal degradation of the unstable terminal groups takes place. The degradation is advantageously effected in the presence of a calcium or magnesium salt of an aliphatic carboxylic acid of low molecular weight. The oxymethylene copolymers are suitable as engineering plastic for preparing semi-finished products and finished products.

    THERMOPLASTIC DRESSING MATERIAL
    69.
    发明专利

    公开(公告)号:GB1292850A

    公开(公告)日:1972-10-11

    申请号:GB5879169

    申请日:1969-12-02

    Applicant: HOECHST AG

    Abstract: 1292850 Surgical casts FARBWERKE HOECHST AG 2 Dec 1969 [2 Dec 1968] 58791/69 Heading A5R [Also in Division B5] A thermoplastic dressing material comprises (i) a textile fabric impregnated and/or coated on one or both sides with at least one copolymer of trioxan and one or more cyclic formals of the formula in which x+y=0 or 1, the polyacetal having a melting point of 40‹-80‹C and the molar ratio of formal: trioxan being 0.7 to 2.8:1, and (ii) at least one sheet of plastics material and aluminium foil coated on one or both sides with polytetrafluorethylene. The fabric may be of cotton, wool, cellulose acetate, polyester or polyacrylonitrile fibres and preferably weighs 10-100 g/m 2 and has a coating thereon 1-5 mm. thick, muslin bandages are preferred. The sheet may be of polypropylene, polyethylene, polyvinylchloride, polyester, cellulose derivatives or aluminium of 10-100 microns in thickness to which the polyetetrafluoroethylene may be applied from aqueous or organic dispersion, e.g. by spraying. The copolymer preferably has a melting point of 40-80‹C and a reduced specific viscosity of 0.6-1.0 U/g (at 140‹C in butrolactone with concentration of 0.5 g/100 ml) and may be applied by extrusion followed by calendering. The sheet may extend beyond the edges of the impregnated fabric.

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