Continuous gas-phase polymerization processes

    公开(公告)号:US10358509B2

    公开(公告)日:2019-07-23

    申请号:US15559792

    申请日:2016-03-23

    Abstract: The present disclosure relates to a continuous process for the preparation of ethylene homopolymers or ethylene copolymers comprising polymerizing ethylene or copolymerizing ethylene and one or more other olefins in the presence of a chromium catalyst in a gas-phase polymerization reactor which is equipped with a cycle gas line for withdrawing reactor gas from the reactor, leading the reactor gas through a heat-exchanger for cooling and feeding the reactor gas back to the reactor, wherein the polymerization is carried out at a temperature from 30° C. to 130° C. and a pressure of from 0.1 to 10 MPa and an aliphatic carboxylic acid ester having from 8 to 24 carbon atoms is added.

    OLEFIN POLYMERIZATION PROCESS
    32.
    发明申请

    公开(公告)号:US20190055328A1

    公开(公告)日:2019-02-21

    申请号:US16079229

    申请日:2017-02-23

    Abstract: A process for the preparation of an ethylene polymer including the step of polymerizing ethylene or copolymerizing ethylene and one or more other olefins in the presence of a Phillips-type chromium catalyst in a gas-phase polymerization reactor containing a reactor bed of particulate polymer, wherein the gas-phase polymerization reactor is equipped with a cycle gas line, wherein the reactor gas returned to the polymerization reactor through the cycle gas line has been condensed in part and the amount of liquid in the returned reactor gas is from 0.5 wt. % to 10 wt. % based upon the total weight of the reactor gas/liquid composition, the polymerization is carried out at from 108° C. to 125° C., and an aluminum alkyl is fed into the polymerization reactor in an amount in the range of from 0.0025 mole to 0.1 mole per ton of dosed ethylene.

    POLYETHYLENE MOLDING COMPOSITION FOR PRODUCING BLOWN FILMS HAVING IMPROVED PROCESSABILITY
    40.
    发明申请
    POLYETHYLENE MOLDING COMPOSITION FOR PRODUCING BLOWN FILMS HAVING IMPROVED PROCESSABILITY 审中-公开
    用于生产具有改进的可加工性的薄膜的聚乙烯模塑组合物

    公开(公告)号:US20160251504A1

    公开(公告)日:2016-09-01

    申请号:US15154800

    申请日:2016-05-13

    Abstract: The invention relates to a polyethylene molding composition having a multimodal molar mass distribution particularly suitable for blow molding films having a thickness in the range from 8 to 200 μm. The molding composition has a density at a temperature of 23° C. in the range from 0.953 to 0.960 g/cm3 and an MFR190/5 of the final product after extrusion in the range from 0.10 to 0.50 dg/min. The composition comprises from 30 to 60% by weight of a first ethylene polymer fraction made of a homopolymer A having a first molecular weight, from 22 to 40% by weight of a second ethylene polymer fraction made of a further homopolymer or first copolymer B of ethylene and at least one first comonomer from the group of olefins having from 4 to 8 carbon atoms, the first copolymer B having a second molecular weight higher than the first molecular weight, and from 10 to 30% by weight of a third ethylene polymer fraction made of a second copolymer C having a third molecular weight higher than the second molecular weight. The molding composition of the invention allows to produce thin films having improved processability without impairing the mechanical properties.

    Abstract translation: 本发明涉及具有特别适用于厚度在8至200μm范围内的吹塑薄膜的多峰摩尔质量分布的聚乙烯模塑组合物。 模塑组合物的密度在23℃的温度范围为0.953至0.960g / cm3,挤出后的最终产品的MFR 190/5为0.10至0.50dg / min。 该组合物包含30至60重量%的由具有第一分子量的均聚物A制成的第一乙烯聚合物部分,22至40重量%的由其它均聚物或第一共聚物B制成的第二乙烯聚合物部分 乙烯和来自具有4至8个碳原子的烯烃基团的至少一种第一共聚单体,第一共聚物B具有高于第一分子量的第二分子量和10至30重量%的第三乙烯聚合物部分 由具有高于第二分子量的第三分子量的第二共聚物C制成。 本发明的模塑组合物允许制造具有改进加工性能的薄膜而不损害机械性能。

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