The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 11, 1987
Filed:
Dec. 09, 1985
Joachim Behnke, Amorbach, DE;
Hans-Jurgen Pitowski, Miltenberg, DE;
AKZO NV, Arnhem, NL;
Abstract
A method is provided for producing a membrane from polycarbonate-polyether-blockcopolymers with about 5 to 35 weight percent of repeating alkyleneethercarbonate units and about 95 to 65 weight percent of repeating bisphenol A-carbonate units, wherein the polyethyleneoxide blocks have a molecular weight from about 1,000 to 20,000, wherein the intrinsic viscosity of the copolymer is from about 180 to 300 ml/g as measured in chloroform at 25.degree. C. and wherein the ultrafiltration rate is from about 4 to 200 ml/h.m.sup.2.mm Hg. In a first dissolving step a polycarbonate-polyether-copolymer is homogeneously mixed with a solvent at a temperature from about 80.degree. to 120.degree. C. and in a second dissolving step the temperature is brought to about 140.degree. to 180.degree. C. to produce a true solution. The filtered solution is cooled to from about 20.degree. to 50.degree. C. and is then extruded through a nozzle into a bath comprising a nonsolvent for the polymer for precipitating the polymer. The precipitated polymer is then washed and dried. The resulting membranes improve the processes of hemodialyzing and of homofiltration.