A hydrophilic composite porous membrane, a method of producing the same and a plasma separator

Claim 2

A hydrophilic composite porous membrane comprising: a polyolefin membranous matrix having pores which are present within the matrix in communicating relationship and form throughpaths running from one surface of the matrix to the other surface of the matrix, and at least one copolymer coat layer formed substantially on the overall surface of the matrix including both the surfaces of the matrix and the inner wall surfaces of said pores, leaving spaces within said pores and leaving openings on both the surfaces of said matrix, said openings respectively communicating with said spaces, said copolymer being water-insoluble and comprised of hydrophilic monomeric units and hydrophobic monomeric units, and having a hydrophilic monomeric unit content of from 40 to 90 % by weight based on ' the copolymer.

Claim 3

A membrane according to claim 1, wherein the or each coat layer covers at least 70 % of the area of said overall surface.

Claim 4

A membrane according to claim 1 or 2, wherein said hydrophobic monomeric units are ethylene units.

Claim 5

A membrane according to any one of claims 1 to 3, wherein said hydrophilic monomeric units are vinyl alcohol units.

Claim 6

A membrane according to any one of claims 1 to 4, wherein said polyolefin is polyethylene or polypropylene.

Claim 7

A membrane according to any one of claims 1 to 5, wherein said matrix is oriented in the stretching direction of the matrix, and said pores within the matrix are elliptic in the cross section taken in the stretching direction of the matrix and are defined by microfibrils that are oriented in the stretching direction of the matrix and knotted portions that are cross-connected to said microfibrils and are each in the form of stacked lamellae, said pores within the matrix including intermediate pores which are present within the matrix in communicating relationship and end pores which open at both the surfaces of the matrix, said intermediate pores and said end pores forming the. throughpaths running between both the surfaces of the matrix.

Claim 8

A membrane according to any one of claims 1 to 6, wherein said spaces have an average pore diameter of from 0.02-ta 4.0 u.m.

Claim 9

A membrane according to any one of claims 1 to 7, wherein said matrix is in the form of a hollow fiber.

Claim 10

A membrane according to any one of claims 1 to 7, wherein said matrix is in the form of a flat membrane.

Claim 13

A method according to claim 10, wherein said solution has a copolymer concentration of from about 0.1 to about 5 % by weight, and said application of the solution is conducted at a temperature of from about 25 °C to less than 100 °C.

Claim 14

A plasma separator comprising: a vessel provided with a blood introduction means, a blood withdrawal means and a plasma withdrawal means; and a plurality of porous hollow fibers which are contained within the vessel, leaving spaces between the inner surface of said vessel and said plurality of porous hollow fibers and between and inside said plurality of porous hollow fibers; said blood introduction mean and said blood withdrawal means communicating with each other through said plurality of porous hollow fibers fluidtightly connected therebetween; said hollow fiber being adapted to pass blood therethrough while causing the plasma component of the blood to be selectively passed through the walls of the hollow fibers and withdrawn through the plasma withdrawal means; each hollow fiber comprising: a polyolefin membranous matrix having pores which are present within the matrix in communicating relationship and form throughpaths running from one surface of the matrix to the other surface of the matrix, and at least one copolymer coat layer formed substantially on the overall surface of the matrix including both the surfaces of the matrix and the inner wall surfaces of said pores, leaving spaces within said pores and leaving openings on both the surfaces of said matraix, said openings respectively communicating with said spaces within said pores, said copolymer being water-insoluble and comprised of hydrophilic monomeric units and hydrophobic monomeric units, and having a hydrophilic monomeric unit content of from 40 to 90 % by weight based on the copolymer.

Claim 15

A plasma separator comprising: a vessel provided with a blood introduction means, a blood withdrawal means and a plasma withdrawal means; and a plurality of porous hollow fibers which are contained within the vessel, leaving spaces between the inner surface of said vessel and said plurality of porous hollow fibers and between and inside said plurality of porous hollow fibers; said blood introduction mean and said blood withdrawal means communicating with each other through said plurality of porous hollow fibers fluidtightly connected therebetween; said hollow fiber being adapted to pass blood therethrough while causing the plasma component of the blood to be selectively passed through the walls of the hollow fibers and withdrawn through the plasma withdrawal means; each hollow fiber comprising: a polyolefin membranous matrix having pores which are present within the matrix in communicating relationship and form throughpaths running from one surface of the matrix to the other surface of the matrix, and at least one copolymer coat layer formed substantially on the overall surface of the matrix including both the surfaces of the matrix and the inner wall surfaces of said pores, leaving spaces within said pores and leaving openings on both the surfaces of said matraix, said openings respectively communicating with said spaces within said pores, said copolymer being water-insoluble and comprised of hydrophilic monomeric units and hydrophobic monomeric units, and having a hydrophilic monomeric unit content of from 40 to 90 % by weight based on the copolymer.