Mitsubishi Rayon Company, Limited

Hironari Honda

Kiyonobu Okamura

Kunio Misoo

Toshinobu Koshoji

Osamu Nishimura

Disclosed is a porous membrane comprising (1) a hydrophilic copolymer X composed principally of (poly)alkylene glycol mono(meth)acrylate units A and ethylene units B and (2) a polyolefin Y, the (poly)alkylene glycol mono(meth)acrylate units A being of the formula ##STR1## where R.sup.1 and R.sup.2 independently represent hydrogen or methyl, and n has a value in the range of 1 to 9. This porous membrane has permanent hydrophilicy suitable for the treatment of water-based liquids and can be produced by an industrially advantageous process. This process comprises melt-forming a blend of (1) a hydrophilic copolymer X composed principally of (poly)alkylene glycol mono(meth)acrylate units A and ethylene units B and (2) a polyolefin Y; heat-treating the melt-formed product in a vacuum or an inert gas medium at a temperature not higher than the melting point of polyolefin Y for a period of an hour or more; and stretching the heat-treated, melt-formed product to make it porous.

Porous membrane and production process thereof

Disclosed are porous polyethylene fibers without a central cavity extending along the longitudinal axis thereof, and having (a) a porous structure containing pores defined by lamellar crystal portions and a large number of fibrils interconnecting the lamellar crystal portions, the pores communicating with each other anywhere from the surface to the center of the fiber, (b) a porosity of 50 to 80%, (c) a tensile strength of 1 to 8 g/d, and (d) an elongation of 1 to 300%. These porous polyethylene fibers do not exhibit the waxy feeling characteristic of polyethylene, have very light weight and a soft feeling, and are useful as a high-strength fiber material for the manufacture of clothing.

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Toyohashi, Japan

Hironari Honda