Microporous membrane materials
AssigneeHooker Chemicals & Plastics Corporation
InventorsChristine A. Lazarz, Edward H. Cook, Jr., Lesleigh V. Scripa
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Abstract
Microporous membrane materials suitable for use in electrolytic cells, such as cells for the electrolysis of brine to produce chlorine, are formed from a mixture of polytetrafluoroethylene, a particulate pore forming material and an organic fluorinated lubricant. Such materials are preferably formed into a sheet, which is rolled to a desired thickness, sintered and subjected to leaching out of the pore forming material.
Claims22
A process for the preparation of a sheet material suitable for use as a separator for an electrolytic cell which comprises:
- (a) forming a sheet from a composition comprising a fluorocarbon polymer, a pore forming additive and a fluorinated surface active agent;
- (b) sintering the sheet;
- and (c) removing the pore forming additive, to form a microporous sheet.
A method of improving the milling characteristics and rolling characteristics of a fluorocarbon polymer--pore forming particulate material mixture which comprises mixing with such mixture a fluorinated surface active agent and milling the mixture resulting.
In the preparation of a microporous sheet material from a fluorocarbon polymer and pore forming material the method of improving the milling and rolling characteristics of a mixture of such polymer and pore forming material which comprises incorporating in the mixture a fluorinated surface active agent which is nonionic.
A process for the preparation of a sheet material suitable for use as a separator for an electrolytic cell which comprises:
- (a) mixing together polytetrafluoroethylene in powder form, a water insoluble particulate pore forming additive and a lower alkanol solution of a nonionic fluorinated surface active agent of the formula F.sub.3 C(CF.sub.2).sub.m CH.sub.2 CH.sub.2 O(CH.sub.2 CH.sub.2 O).sub.n H, wherein m is in the range of 3 to 19 and n is in the range of from 6 to 19;
- (b) milling the mixture to form a sheet;
- (c) sintering the sheet, and (d) removing the pore forming particulate material.
In the preparation of a microporous sheet material from polytetrafluoroethylene and a water insoluble particulate pore forming material the method of improving the milling and rolling characteristics of the mixture which comprises incorporating in the mixture a perfluorinated polyethylene glycol nonionic surface active agent.
Dependencies are inferred from the claim text.