Diaphragm cloth for water electrolyzer and manufacturing method therefor

Abstract

A diaphragm cloth for a water electrolyzer includes a woven fabric, non-woven cloth or knitted fabric composed of alkali-resistant fiber at a common use temperature of no less than 150° C., an average pore size of the diaphragm cloth is less than 10 μm and, under conditions of pressure of 3 KPa, venting quality of the diaphragm cloth is 2 L/cm 2 /min or less.

1 - 19 . (canceled) 
     
     
         20 . A diaphragm cloth for a water electrolyzer comprising a woven fabric, non-woven cloth or knitted fabric composed of alkali-resistant fiber at a common use temperature of no less than 150° C., an average pore size of the diaphragm cloth is less than 10 μm and, under conditions of pressure of 3 KPa, venting quality of the diaphragm cloth is 2 L/cm 2 /min or less. 
     
     
         21 . The diaphragm cloth according to  claim 20 , wherein said alkali-resistant fiber at a common use temperature of above 150° C. is at least one selected from the group consisting of polyphenylene sulfide fiber, polytetrafluoroethylene fiber, poly(p-phenylene benzobisoxazole) fiber and poly(ether-ether-ketone) fiber. 
     
     
         22 . The diaphragm cloth according to  claim 21 , wherein said alkali-resistant fiber at a common use temperature of no less than 150° C. is polyphenylene sulfide fiber. 
     
     
         23 . The diaphragm cloth according to  claim 20 , wherein the alkali-resistant fiber at a common use temperature of above 150° C. contains hydrophilic groups on its surface, and the content of oxygen element on a surface of the fiber is 12 wt % or more. 
     
     
         24 . The diaphragm cloth according to  claim 23 , wherein said content of oxygen element on the fiber surface is 15-40 wt %. 
     
     
         25 . The diaphragm cloth according to  claim 23 , wherein said hydrophilic groups are at least one selected from the group consisting of carboxyl groups, carbonyl groups, hydroxyl groups and formyl groups, and total content of the hydrophilic groups is 10-60% of the total content of the groups on the fabric surface. 
     
     
         26 . The diaphragm cloth according to  claim 20 , wherein pores with a pore size of 0.2-10 μm in the diaphragm cloth take up no less than 60% of all pores. 
     
     
         27 . The diaphragm cloth according to  claim 20 , wherein stiffness of the diaphragm cloth in both warp and weft directions is no less than 3 N. 
     
     
         28 . The diaphragm cloth according to  claim 20 , wherein stiffness of the diaphragm cloth in both warp and weft directions is no less than 5 N. 
     
     
         29 . The diaphragm cloth according to  claim 22 , wherein the polyphenylene sulfide fiber contains no less than 20 wt % of modified cross-section polyphenylene sulfide fiber. 
     
     
         30 . The diaphragm cloth according to  claim 29 , wherein said modified cross-section polyphenylene sulfide fiber is crossed, latticed, polygonal, leaf-shaped, elliptic or flat cross-section polyphenylene sulfide fiber. 
     
     
         31 . The diaphragm cloth according to  claim 20 , wherein said woven fabric is plain cloth. 
     
     
         32 . The diaphragm cloth according to  claim 31 , wherein the plain cloth has a cover factor of 2300 to 3000. 
     
     
         33 . The diaphragm cloth according to  claim 20 , wherein said knitted fabric is wrap-knitted fabric. 
     
     
         34 . A method of manufacturing the diaphragm cloth according to  claim 20 , comprising:
 weaving, non-weaving or knitting with alkali-resistant fiber at a common use temperature of no less than 150° C. to obtain high-temperature-resistant and alkali-resistant woven fabric, non-woven cloth or knitted fabric, refining and drying the woven fabric or knitted fabric after weaving; and   subjecting a surface of the obtained woven fabric, non-woven cloth or knitted fabric to discharge modification to obtain the diaphragm cloth.   
     
     
         35 . The method according to  claim 34 , wherein said discharge modification is plasma treatment or electric ironing treatment. 
     
     
         36 . The method according to  claim 35 , wherein said plasma treatment is vacuum plasma surface treatment or atmospheric pressure plasma surface treatment. 
     
     
         37 . The method according to  claim 36 , wherein, during the vacuum plasma surface treatment, the process gas is selected from the group consisting of oxygen, argon, a gas mixture of oxygen and argon, carbon dioxide and air, pressure of a vacuum chamber is 5-100 Pa, and treatment intensity is 50-500 KW·s/m 2 . 
     
     
         38 . The method according to  claim 36 , wherein, during the atmospheric pressure plasma surface treatment, the process gas is air, and treatment intensity is 50-500 KW·s/m 2 .