Aqueous dispersions of polytetrafluoroethylene having a low amount of fluorinated surfactant
    31.
    发明申请
    Aqueous dispersions of polytetrafluoroethylene having a low amount of fluorinated surfactant 失效
    具有少量氟化表面活性剂的聚四氟乙烯的水分散体

    公开(公告)号:US20050107518A1

    公开(公告)日:2005-05-19

    申请号:US10962633

    申请日:2004-10-12

    摘要: The present invention provides a method of making an aqueous dispersion of non-melt processible polytetrafluoroethylene, the method comprising: (a) an aqueous emulsion polymerization of an amount of tetrafluoroethylene to produce a final amount of polytetrafluoroethylene solids and optionally up to 1% by weight based on the amount of tetrafluoroethylene of a perfluorinated comonomer, wherein said aqueous emulsion polymerization is initiated with a free radical initiator and the polymerization is carried out in the presence of a fluorinated surfactant, and wherein before completing the feeding of said amount of tetrafluoroethylene but after feeding at least 80% by weight of said amount of tetrafluoroethylene, free radicals capable of introducing ionic end groups or precursors thereof in the polytetrafluoroethylene polymer are caused to be formed at a rate that without counter measures would cause an increase in the polymerization rate of at least 20%; (b) reducing the amount of fluorinated surfactant in the thus obtained aqueous dispersion to an amount of not more than 200 ppm, preferably not more than 100 ppm and more preferably not more than 50 ppm based on the amount of polytetrafluoroethylene solids. The invention further provides an aqueous dispersion of polytetrafluoroethylene particles and the use thereof in coating a substrate.

    摘要翻译: 本发明提供了一种制备不熔融可加工聚四氟乙烯的水性分散体的方法,该方法包括:(a)一定量的四氟乙烯的水乳液聚合以产生最终量的聚四氟乙烯固体,并且任选地高达1重量% 基于全氟化共聚单体的四氟乙烯的量,其中所述水性乳液聚合由自由基引发剂引发,并且聚合在氟化表面活性剂的存在下进行,并且其中在完成所述量的四氟乙烯之前但之后 加入至少80重量%的所述量的四氟乙烯,使得能够在聚四氟乙烯聚合物中引入离子端基或其前体的自由基以不加对策的方式形成,导致聚四氟乙烯聚合速率的升高 至少20%; (b)将由此得到的水性分散体中的氟化表面活性剂的量减少到基于聚四氟乙烯固体量不超过200ppm,优选不超过100ppm,更优选不大于50ppm的量。 本发明还提供聚四氟乙烯颗粒的水分散体及其在涂布基材中的用途。

    Aqueous dispersions of polytetrafluoroethylene particles
    32.
    发明申请
    Aqueous dispersions of polytetrafluoroethylene particles 有权
    聚四氟乙烯颗粒的水分散体

    公开(公告)号:US20050090601A1

    公开(公告)日:2005-04-28

    申请号:US10957898

    申请日:2004-10-04

    CPC分类号: C09D127/18 C08L2666/28

    摘要: The present invention provides an aqueous non-melt processible polytetrafluoroethylene dispersion comprising non-melt processible polytetrafluoroethylene particles in an amount between 30 and 70% by weight based on the total weight of the dispersion and one or more non-ionic surfactants and wherein at least a part of said non-melt processible polytetrafluoroethylene particles comprise polytetrafluoroethylene polymer chains having repeating units comprising ionic groups. The invention further provides a method for obtaining the dispersions.

    摘要翻译: 本发明提供了一种含水不可熔融加工的聚四氟乙烯分散体,其包含基于分散体和一种或多种非离子表面活性剂的总重量为30-70重量%的不可熔融加工的聚四氟乙烯颗粒,并且其中至少一个 所述不可熔融加工的聚四氟乙烯颗粒的一部分包括具有包含离子基团的重复单元的聚四氟乙烯聚合物链。 本发明还提供了获得分散体的方法。

    Degassing apparatus and use thereof
    37.
    发明授权
    Degassing apparatus and use thereof 失效
    脱气装置及其用途

    公开(公告)号:US5634963A

    公开(公告)日:1997-06-03

    申请号:US546614

    申请日:1995-10-23

    摘要: An apparatus suitable in particular for degassing fluoropolymers which have been subjected to thermal degradation contains--in the direction of flow of the product--a product intake, a coolable conveyor section, a comminution apparatus, a heated conveyor section and a product discharge, the entire apparatus being designed to be gastight and advantageously being designed to be resistant to pressure surges and having a gas outlet in the area of the coolable conveyor section and/or in the area of the comminution apparatuses.

    摘要翻译: 特别适用于对经过热降解的含氟聚合物进行脱气的设备包括 - 产品流动方向 - 产品入口,可冷却输送段,粉碎设备,加热输送段和产品排放物,整个 设备被设计为气密的并且有利地设计成抵抗压力冲击并且在可冷却输送机部分的区域中和/或在粉碎设备的区域中具有气体出口。