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    PROCESS FOR THE PREPARATION OF POLYACETAL COPOLYMERS
    1.
    发明专利
    PROCESS FOR THE PREPARATION OF POLYACETAL COPOLYMERS 未知

    公开(公告)号：CA2157456A1

    公开(公告)日：1996-03-06

    申请号：CA2157456

    申请日：1995-09-01

    Applicant: HOECHST AG

    Inventor： HOFFMOCKEL MICHAEL ,  MUECK KARL-FRIEDRICH ,  FLEISCHER DIETRICH ,  SEXTRO GUENTER

    IPC: C08G2/10 ,  C08G2/00 ,  C08G2/18 ,  C08G2/24 ,  C08G2/28

    Abstract: In the process for the preparation, with simultaneous end group stabilization, of polyacetal copolymers in a homogeneous phase and working up thereof, cyclic formaldehyde oligomers are copolymerized with cyclic acetals in the presence of an initiator in a polymerization reactor and immediately thereafter the initiator is deactivated by addition of basic substances, the unstable chain ends being degraded down to 0.01% to 1% in the presence of residual monomer, the product losing the majority of the residual monomer at the reactor outlet by letting down into a pelletizing device and the residual monomer which remains and the impurities dissolved in the product being removed by extraction with solvents and the product being pelletized, after drying and stabilization.

    CONTINUOUS PROCESS FOR REMOVING UNSTABLE COMPONENTS FROM CRUDE OXYMETHYLENE COPOLYMER
    6.
    发明专利
    CONTINUOUS PROCESS FOR REMOVING UNSTABLE COMPONENTS FROM CRUDE OXYMETHYLENE COPOLYMER 未知

    公开(公告)号：CA1307871C

    公开(公告)日：1992-09-22

    申请号：CA558207

    申请日：1988-02-05

    Applicant: HOECHST AG

    Inventor： SEXTRO GUENTER ,  MUECK KARL-FRIEDRICH ,  BURG KARLHEINZ ,  FISCHER EBERHARD

    IPC: C08G2/10 ,  C08G2/28

    Abstract: HOE 87/F 037 Continuous process for removing unstable components from crude oxymethylene copolymer, which still contains catalysts, monomeric starting materials and unstable components, by treating the copolymer with deactivators, optionally in the presence of auxiliaries, in a pressure zone, and subsequently removing volatile components in a pressure-release zone in the presence or absence of stabilizers, in which process the crude polymer is fully melted in the absence of the deactivators and auxiliaries immediately after completion of the polymerization step, and the deactivators are subsequently incorporated, alone or together with auxiliaries, under pressure into the resultant polymer melt in at least one pressure zone. By this process, degradation is avoided and significantly better properties are contained.

    PROCESS FOR THE CONTINUOUS MANUFACTURE OF TRIOXAN
    8.
    发明专利
    PROCESS FOR THE CONTINUOUS MANUFACTURE OF TRIOXAN 未知

    公开(公告)号：CA1125774A

    公开(公告)日：1982-06-15

    申请号：CA341491

    申请日：1979-12-07

    Applicant: HOECHST AG

    Inventor： MUCK KARL-FRIEDRICH ,  SEXTRO GUENTER ,  BURG KARLHEINZ

    IPC: C07D317/12 ,  C07D323/06

    Abstract: HOE 78/F 266 PROCESS FOR THE CONTINUOUS MANUFACTURE OF TRIOXAN of the disclosure: The invention provides a process for the continuous manufacture of trioxan, optionally together with cyclic formals, from aqueous formaldehyde solutions in a circulation reactor with evaporator, the vapor amount leaving the system being in the range of from 0.1 to 4 %. The process of the invention allows to attain especially high space/time yields.

    10.
    发明专利
    未知

    公开(公告)号：DK140850B

    公开(公告)日：1979-11-26

    申请号：DK496675

    申请日：1975-11-05

    Applicant: HOECHST AG

    Inventor： SEXTRO GUENTER ,  BURG KARLHEINZ ,  LEUGERING HANS JOACHIM ,  SCHLAF HELMUT ,  HELLER ALWIN

    IPC: C08G2/00 ,  C08J3/14 ,  C08J3/16 ,  C08L59/00

    Abstract: Oxymethylene polymers (POM) are obtained in granular form by cooling a POM solution or dispersion having a temperature above the sintering temperature of the POM in two stages to a temperature just below the said sintering temperature. The solvent or dispersion agent used is a mixture of methanol and water and the cooling agent is a methanol/water mixture which may contain POM suspended therein. The granular POM obtained is suitable as technical material for making shaped articles.

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