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US 4,189,369 AGranted
Diaphragm of hydrophilic fluoropolymers
AssigneeE. I. Du Pont de Nemours and Company
InventorJames C. Fang
Life of this patent
Estimating the term…
Abstract
Certain fluoropolymers, when chemically modified by reacting them with sulfur or phosphorus containing compounds, become hydrophilic materials useful for making ion-exchange membranes, especially diaphragms for electrolytic cells, particularly chlor-alkali cells used in the production of chlorine, hydrogen and sodium hydroxide from brine.
Claims3
A diaphragm for a chlor-alkali cell comprising a hydrophilic fluoropolymer containing nonterminal units represented by the structure ##STR28## where M is hydrogen, sodium, potassium, lithium, calcium or magnesium;
- R is an alkyl radical of 1-12 carbon atoms or a cycloalkyl radical of 3-12 carbon atoms;
- and
- x is 1, 2, 3, 4 or 5, the hydrophilic fluoropolymer having a sulfur or phosphorus content of about 0.1-10% by weight, not more than about 1% by weight of the fluoropolymer dissolving in water at 20.degree. C., and a fibrous material resistant to attack by the cell liquor.
Dependencies are inferred from the claim text.