Novel polytetrafluoroethylene fine powder
    2.
    发明授权
    Novel polytetrafluoroethylene fine powder 失效
    新型聚四氟乙烯细粉

    公开(公告)号:US4714748A

    公开(公告)日:1987-12-22

    申请号:US858836

    申请日:1986-04-29

    CPC分类号: C08F114/26

    摘要: Polytetrafluoroethylne fine powder is disclosed having an average molecular weight of at least 6,000,000, an amorphous index larger than 0.1 and a number average primary particle size of 0.1 to 0.8 micron, and further having a clear endothermic peak at a temperature of 347.degree..+-.3.degree. C. and another endothermic peak or shoulder at a temperature between 330.degree. C. and the temperature of said clear endothermic peak on a crystalline melting chart recorded by a differential scanning calorimeter. An unsintered article is made which is sintered and expanded at a temperature higher than the melting point of the polytetrafluoroethylene to give a porous article having improved properties.

    摘要翻译: 公开了具有平均分子量至少为6,000,000,无定形指数大于0.1和数均一次粒径为0.1至0.8微米的聚四氟乙烯微粉末,并且在347度+/-的温度下还具有清晰的吸热峰 在330℃的温度和通过差示扫描量热计记录的结晶熔融图上的所述透明吸热峰的温度之间的另一个吸热峰或肩峰。 制造未烧结制品,其在比聚四氟乙烯的熔点高的温度下烧结和膨胀,得到具有改进性能的多孔制品。

    Modified tetrafluoroethylene polymer and process for producing same
    3.
    发明授权
    Modified tetrafluoroethylene polymer and process for producing same 失效
    改性四氟聚乙烯聚合物及其生产方法

    公开(公告)号:US4134995A

    公开(公告)日:1979-01-16

    申请号:US874422

    申请日:1978-02-02

    CPC分类号: C08F214/262 C08F259/08

    摘要: In a process for polymerization of tetrafluoroethylene with a copolymerizable modifier in an aqueous medium containing a polymerization initiator and a dispersant to produce a modified tetrafluoroethylene polymer containing 0.001 to 2 wt.% of the copolymerizable modifier based on the weight of the polymer, a process for producing the modified tetrafluoroethylene polymer characterized in that:(1) chlorotrifluoroethylene is used as said copolymerizable modifier,(2) at least 50 wt.% of the copolymerizable modifier to be incorporated into the polymer is introduced into the polymerization system after 70 wt.% of the polymer to be finally formed has been formed, and(3) after 90 wt.% of the polymer to be finally formed has been formed, the concentration of said copolymerizable modifier is maintained at at least 0.01 mol.% based on the total amount of tetrafluoroethylene and the modifier in the polymerization system.