초록 ▼

A process for the preparation of soft porous sheets, comprises forming into a sheet a composition comprising (i) 40 to 80% by weight of an inorganic filler and (ii) 60 to 20% by weight of a polyolefin type thermoplastic elastomer composition comprising at least 50% by weight of a polyolefin type the

A process for the preparation of soft porous sheets, comprises forming into a sheet a composition comprising (i) 40 to 80% by weight of an inorganic filler and (ii) 60 to 20% by weight of a polyolefin type thermoplastic elastomer composition comprising at least 50% by weight of a polyolefin type thermoplastic elastomer substantially free of a polar group, in which the tensile stress at a temperature of 25°C. under 100% stretching (100% modulus) is 10 to 100 Kg/cm2, the elongation at break under stretching is at least 100% and the permanent strain under 100% stretching is less than 50% and up to 50% by weight of a thermoplastic plastomer, and stretching the sheet at a temperature lower than the softening temperature of the polyolefin type thermoplastic elastomer. A porous sheet obtained according to this process has a good combination of flexibility, air permeability and water resistance.

대표청구항 ▼

A porous sheet comprising (i) 40 to 80% by weight of an inorganic filler and (ii) 60 to 20% by weight of a polyolefin type thermoplastic elastomer composition comprising at least 50% by weight of a polyolefin type thermoplastic elastomer selected from the group consisting of an ethylene-propylene co

A porous sheet comprising (i) 40 to 80% by weight of an inorganic filler and (ii) 60 to 20% by weight of a polyolefin type thermoplastic elastomer composition comprising at least 50% by weight of a polyolefin type thermoplastic elastomer selected from the group consisting of an ethylene-propylene copolymer, an ethylene-propylene-diene copolymer and an ethylene-butene-1 copolymer, in which the tensile stress at a temperature of 25°C. under 100% stretching (100% modulus) is 10 to 100 kg/cm2, the elongation at break under stretching is at least 100% and the permanent strain under 100% stretching is less than 50% and up to 50% by weight of a thermoplastic polyolefin resin plastomer, said sheet being stretched in at least one direction and having fine communicating pores in the interior thereof, wherein the initial tensile elastic modulus is lower than 500 kg/cm2, the permanent strain after 50% stretching is lower than 50%, the air permeability is lower than 10000 sec/100 cc, the water pressure resistance is at least 1000 mmH2O, the maximum pore size is smaller than 10 microns and the elongation at break is at least 50%.