Electrolytic cell including a flexible sheet covering the cell base

Claim 2

IN AN ELECTROLYTIC CELL OF THE DIAPHRAGM TYPE FOR THE PRODUCTION OF CHLORINE, SAID CELL COMPRISING A CELL CAN FOR CONTAINING A BRINE SOLUTION, CONDUCTIVE METAL CELL BASE SUPPORTING SAID CAN AND ANODE MEMBERS DISPOSED WITHIN SAID CAN AND EXTENDING THROUGH SAID BASE; A FLEXIBLE HEAT-RESISTANT ELASTOMERIC SHEET COVERING AND IN CONTACT WITH SAID CELL BASE ABND SUBJECTED TO THE HEAT GENERATED BY THE CONDUCTIVE METAL OF THE CELL BASE, SAID SHEET COMPRISED OF A VULCANIZED HEAT-RESISTANT BLEND OF A FIRST VULCANIZED RUBBERY POLYMER WHICH WILL SOFTEN UNDER THE PROLONGATED INFLUENCE OF HEAT WHEREIN SAID FIRST POLYMER IS A POLYISOPRENE SELECTED FROM THE GROUP CONSISTING OF NATURAL RUBBER AND SYNTHETIC RUBBER OF A CIS 1,4-POLYMER OF ISOPRENE AND A SECOND VULCANIZED HEAT-RESISTANT RUBBERY POLYMER WHICH WILL HARDEN UNDER THE PROLONGED INFLUENE CE OF HEAT WHEREIN SAID SECOND POLYMER IS AT LEAST ONE POLYMER SELECTED FROM THE GROUP CONSISTING OF HALOGENATED BUTYL RUBBER, ETHYLENE PROPYLENE TERPOLYMER RUBBER, A COPOLYMER OF BUTADIENE AND ACRYLONITRILE, A COPOLYMER OF BUTADIENE AND STYRENE AND A CHLOROSULFONATED POLYETHYLENE AND WHEREIN THE WEIGHT RATIO OF SAID POLYISOPRENE TO SAID SECOND POLYMER IS FROM ABOUT 35/65 TO ABOUT 65/35, SAID SHEET, DUE TO THE COMBINED EFFECTS OF SAID FIRST AND SECOND POLYMERS, THEREBY RETAINING ITS FLEXIBLE REILIENT CHARACTERISTICS TO PROVIDE A SEAL BETWEEN THE CELL BASE AND BER AND THE CELL BASE AND BETWEEN THE CELL BASE AND THE BRINE BRINE SOLUTION CONTAINED IN THE CAN.

Claim 3

The invention as claimed in claim 1 wherein the sheet when tested for 7 days at 250*F in accordance with ASTM D-573 will exhibit a hardness increase of less than 10 points as measured on the Shore A scale.

Claim 4

The invention as claimed in claim 1 wherein said halogenated butyl rubber is selected from the group consisting of chlorinated butyl and brominated butyl rubber.

Claim 5

The invention as claimed in claim 3 wherein said second polymer is at least one polymer selected from the group consisting of chlorinated butyl rubber, brominated butyl rubber and ethylene propylene terpolymer rubber.

Claim 6

The invention as claimed in claim 1 wherein said second polymer is chlorinated butyl rubber anad the weight ratio of polyisoprene to said chlorinated butyl rubber is from about 45/55 to about 55/45.

Claim 7

The invention as claimed in claim 1 wherein said second polymer is ethylene propylene terpolymer rubber and the weight ratio of polyisoprene to said ethylene propylene terpolymer rubber is from about 35/65 to about 45/55.

Claim 8

In an electrolytic cell of the diaphragm type comprising the combination of a cell can for containing a brine solution, a conductive metal cell base supporting said can, cathodes and dimensionally stable anodes disposed within the can with the anodes connected to anode risers which extend through the cell base, and an electrically non-conductive vulcanized elastomeric sheet covering substantially the entire cell base serving to provide a compressible seal between the anodes and the cell base and between the cell can and the cell base with the sheet subjected to the heat generated by the conductive metal of the cell base, the improvement wherein said sheet is comprised of a heat-resistant vulcanized blend of a first vulcanized rubbery polymer which will soften under the prolonged influence of heat wherein said first polymer is a polyisoprene selected from the group consisting of natural rubber and synthetic rubber of a cis 1,4-polymer of isoprene and a second vulcanized rubbery polymer which will harden under the prolonged influence of heat wherein said second polymer is at least one polymer selected from the group consisting of halogenated butyl rubber, ethylene propylene terpolymer rubber, a copolymer of butadiene and acrylonotrile, a copolymer of butadiene and styrene and a chlorosulfonated polyethylene and wherein the weight ratio of said polyisoprene to said second polymer is from about 35/65 to about 65/35, said sheet, due to the combined effects of said first and second polymers, thereby retaining its flexible resilient characteristics to prevent cracking of the sheet at the juncture between the anode risers and the cell base and the resulting leakage of the brine solution onto the conductive metal of the base.

Claim 9

In an electrolytic cell of the diaphragm type comprising the combination of a cell can for containing a brine solution, a conductive metal cell base supporting said can, cathodes and dimensionally stable anodes disposed within the can with the anodes connected to anode risers which extend through the cell base, and an electrically non-conductive vulcanized elastomeric sheet covering substantially the entire cell base serving to provide a compressible seal between the anodes and the cell base and between the cell can and the cell base with the sheet subjected to the heat generated by the conductive metal of the cell base, the improvement wherein said sheet is comprised of a heat-resistant vulcanized blend of a first vulcanized rubbery polymer which will soften under the prolonged influence of heat wherein said first polymer is a polyisoprene selected from the group consisting of natural rubber and synthetic rubber of a cis 1,4-polymer of isoprene and a second vulcanized rubbery polymer which will harden under the prolonged influence of heat wherein said second polymer is at least one polymer selected from the group consisting of halogenated butyl rubber, ethylene propylene terpolymer rubber, a copolymer of butadiene and acrylonotrile, a copolymer of butadiene and styrene and a chlorosulfonated polyethylene and wherein the weight ratio of said polyisoprene to said second polymer is from about 35/65 to about 65/35, said sheet, due to the combined effects of said first and second polymers, thereby retaining its flexible resilient characteristics to prevent cracking of the sheet at the juncture between the anode risers and the cell base and the resulting leakage of the brine solution onto the conductive metal of the base.

Claim 10

The invention as claimed in claim 7 wherein said sheet is comprised of at least a single layer of said first and second polymer with said layer in contact with a flanged member of said anode riser.

Claim 11

The invention as claimed in claim 7 wherein the sheet, when tested for 7 days at 250*F in accordance with ASTM D-573, will exhibit a hardness increase of less than 10 points as measured on the Shore A scale.

Claim 12

The invention as claimed in claim 7 wherein said halogenated butyl rubber is selected from the group consisting of chlorinated butyl and brominated butyl rubber.

Claim 13

The invention as claimed in claim 10 wherein said second polymer is at least one polymer selected from the group consisting of chlorinated butyl rubber, brominated butyl rubber and ethylene propylene terpolymer rubber.

Claim 14

The invention as claimed in claim 7 wherein said second polymer is chlorinated butyl rubber and the weight ratio of polyisoprene to said chlorinated butyl rubber is from about 45/55 to about 55/45.

Claim 15

The invention as claimed in claim 7 wherein said second polymer is ethylene propylene terpolymer rubber and the weight ratio of polyisoprene to said ethylene propylene terpolymer rubber is from about 35/65 to about 45/55.