Porous hydrophilic polypropylene membrane, method for production

Details Porous hydrophilic polypropylene membrane, method for production Porous hydrophilic polypropylene membrane, method for production

1990-04-26

1993-02-16

Spear, Frank

Liquid purification or separation

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21050038, 264 49, B01D 6700

Patent

active

051868350

DESCRIPTION:

BRIEF SUMMARY
DESCRIPTION

1. Technical Field
This invention relates to a porous hydrophilic polypropylene membrane, a method for the production thereof, and a blood plasma separation apparatus. More particularly, it relates to a flat sheetlike porous polypropylene membrane, a method for the production thereof, and a blood plasma separation apparatus. Still more particularly, this invention relates to a flat sheetlike porous hydrophilic polypropylene membrane which excels in compatibility to blood and dimensional stability and which, when used for the separation of blood plasma, permits quick separation of blood plasma and has a remote possibility of suffering from embedment of blood cells or hemolysis, a method for the production thereof, and a blood plasma separation apparatus.
2. Background Art
Heretofore, various permeable membranes have found utility for the separation of blood into the component of blood cells and the component of blood plasma. The permeable membranes are now used for the defecation of blood plasma aimed at removal of abnormal protein, immune complex, antigen, and antibody from patients with diseases due to abnormal immunity such as general erythematodes, chronic arthrorheumatism, glomerular nephtrities, and bulbospinal paralysis, for the preparation of blood plasma agents for componental transfusion, for the pretreatment of artificial kidneys, and so on. For example, cellulose acetate membranes (Japanese Patent Laid-Open SHO 54(1979)-15,476), polyvinyl alcohol membranes, polyester membranes, polycarbonate membranes, polymethyl methacrylate membranes, polyethylene membranes (Japanese Patent Laid-Open SHO 57(1982)-84,702), and polypropylene membranes have been used as permeable membranes for the separation of blood plasma. These permeable membranes are deficient in mechanical strength, porosity, and ability to separate blood plasma. When they are used for the separation of blood plasma, the red blood cells sustain injury due to clogging, the complemental component in the blood plasma is suffered to undergo activation, and the separated blood plasma is seriously injured ("Artificial Internal Organs," Vol. 16 No. 2, pp. 1045-1050) (1987).
A permeable membrane produced by mixing a polymer such as crystalline polyolefin or polyamide which exhibits sparing solubility in solvents and possesses expandability with a compound which possesses partial compatibility with the polymer and exhibits ready solubility in solvents, molding the resultant mixture into a film, a sheet, or a hollow article, treating the molded article with a solvent, drying the wet molded article, and thereafter stretching the dried molded article uniaxially or biaxially by a ratio in the range of 50 to 15,000% has been proposed (Japanese Patent Publication SHO 57(1982)-20,970). Since this membrane is stretched for the purpose of enlarging the pores in diameter, it has a large thermal shrinkage such that, when used as a medical material, it cannot tolerate the impact of sterilization in an autoclave. Further, since this membrane acquires its porous texture in consequence of the stretching, the pores are linear extensions substantially parallel to the direction of all thickness of the membrane and have a substantially uniform cross section in the opposite surface parts and in the interior part thereof. When this membrane is used for the separation of blood plasma, therefore, the pores therein are highly liable to be clogged with proteins and blood cells.
Regarding the applicability of a permeable membrane to the separation of blood plasma, polyolefin type macromolecular compounds have been attracting attention as a material characterized by manifesting only an insignificant complemental activity. Thus, permeable membranes using polyolefin type macromolecular compounds are being studied with respect to their feasibility in the intended application under discussion. For example, a method for producing a porous membrane by melt mixing 10 to 80% by weight of a paraffin with 90 to 20% by weight of a polypropylene resin, extruding the resultant

REFERENCES:
patent: 3083118 (1963-03-01), Bridgeford
patent: 4501793 (1985-02-01), Sarada
patent: 4597868 (1986-07-01), Watanabe
patent: 4845132 (1989-07-01), Masuoka et al.

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