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AssigneeX-Flow B.V.
InventorsHendrik D. W. Roesink, Dirk M. Koenhen, Marcellinus H. V. Mulder, Cornelis A. Smolders
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The invention relates to a process for preparing a microporous membrane, starting from a mixture of at least a hydrophobic polymer and a hydrophilic polymer, by dissolving these polymers first in a suitable solvent or mixture of solvents and subsequently by coagulating in a coagulation bath. According to the invention a more or less hydrophilic membrane is prepared by removing the membrane so obtained from the coagulation bath and subsequently by leaching at least a part of the hydrophilic polymer from the matrix, alternatively followed by hydrophobization. Said leaching of the hydrophilic polymer occurs by treatment of the membrane with an oxidizing/hydrolizing agent. The invention furthermore comprises microporous membranes, flat or tubular or in the form of hollow fibers, having a good chemical resistance and good mechanical strength.
A process for preparing a microporous membrane comprising dissolving a hydrophobic polymer and a hydrophilic polymer in a suitable solvent or mixture of solvents to obtain a polymer solution, and subsequently coagulating the polymer solution in a coagulation bath to obtain a membrane, removing the membrane so obtained from the coagulation bath and subsequently chemically reacting said membrane to remove at least a part of the hydrophilic character of the polymer, alternatively followed by hydrophobisation.
A process for preparing a microporous membrane comprising dissolving a hydrophobic polymer and a hydrophilic polymer in a suitable solvent or mixture of solvents to obtain a polymer solution, and subsequently coagulating the polymer solution in a coagulation bath to obtain a membrane, removing the membrane so obtained from the coagulation bath and subsequently chemically reacting said membrane with an oxidising/hydrolising agent to remove at least a part of the hydrophilic character of the polymer, alternatively followed by hydrophobisation.
Microporous membranes which can be made hydrophobic by heat treatment, flat or tubular or in the form of a hollow fibers, essentially comprising at least a hydrophobic polymer and a hydrophilic polymer, which hydrophilic polymer has been cross-linked and has been fixated in or at the polymer matrix, the membrane having pores of 0.0001-5 /um, a heat resistance up to 250.degree. C., a water permeability up to 8000 1/m2.h.bar, also having a good chemical resistance and good mechanical strength.
Dependencies are inferred from the claim text.