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US 4,055,696 AGranted
Porous polypropylene hollow filaments and method making the same
AssigneeMitsubishi Rayon Co., Ltd.
InventorsKensuke Kamada, Shunsuke Minami, Kanji Yoshida
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Abstract
There are disclosed porous polypropylene hollow filaments which have a surrounding wall portion of less than 60 .mu., preferably 40 .mu. in thickness which contains many fine holes communicating with each other, distribution curve of radius of said fine holes having at least one maximum points within the range of 200-1200 A. The method for producing said porous polypropylene hollow filaments is also disclosed.
Claims2
Porous polypropylene hollow filaments consisting essentially of polypropylene, wherein;
- the thickness of the surrounding wall portion is less than 60 .mu.;
- many fine interconnecting holes are present in said surrounding wall portion;
- the distribution curve of the radius of said fine holes has at least one maximum point within the range of 200-1200 A;
- said porous polypropylene filaments being more permeable to nitrogen gas than to oxygen gas and;
- wherein said porous polypropylene hollow filaments have been prepared by
2 more elements
Dependencies are inferred from the claim text.