Abstract: 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.

Abstract: 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.

Abstract: A porous polyethylene film was obtained which is characterized in that micropores are contiguous with one another from one surface to the other surface of the film to constitute a laminar structure, and said micropores assume the form of strips being composed of microfibrils that are arrayed in a direction in which the film is stretched and nodular portions that are coupled to said microfibrils nearly at right angles thereto, wherein the micropores have an average pore diameter over a range of 0.05 to 2 microns as measured using a mercury porosimeter, said film has a porosity over a range of 30 to 90%, and an elastic recovery factor from the 50% stretching ratio is less than 50%.

Abstract: A suede-like sheet material characterized by being formed of a base cloth and ultrafine fibers of a denier less than 0.5 per filament, said ultrafine fibers being entangled with each other and covering at least one surface of the base cloth, wherein a portion of said ultrafine fibers is stuffed into the gaps in the network of the base cloth, at least a portion of said ultrafine fibers being entangled with the component fibers of the base cloth, and said base cloth and ultrafine fibers being substantially integrated with each other.

Abstract: A suede-like sheet material characterized by being formed of a base cloth and ultrafine fibers of a denier less than 0.5 per filament, said ultrafine fibers being entangled with each other and covering at least one surface of the base cloth, wherein a portion of said ultrafine fibers is stuffed into the gaps in the network of the base cloth, at least a portion of said ultrafine fibers being entangled with the component fibers of the base cloth, and said base cloth and ultrafine fibers being substantially integrated with each other.