Breathable barrier films containing cavated fillers

    公开(公告)号:US06569225B2

    公开(公告)日:2003-05-27

    申请号:US09732258

    申请日:2000-12-07

    IPC分类号: B01D5302

    摘要: A breathable, stretch-thinned barrier film having improved strength, processability and/or breathability is formed from a mixture of a thermoplastic polymer and cavated filler particles such as cyclodextrin. The cavated filler particles provide the film with enhanced breathability to water vapor due to their ring-like, conical, cylindrical or otherwise hollow molecular structure, yet the film remains substantially impermeable to aqueous liquids. The enhanced breathability occasioned by the cavated particles permits the use of relatively low filler levels and correspondingly high polymer levels, thereby enhancing the film strength. The filler may melt during extrusion of the molten polymer into a film, facilitating smooth processing, and re-crystallize into particles after the film is formed and cooled.