Liquid composition
To provide a liquid composition containing a fluoropolymer having sulfonic acid functional groups, which rarely corrodes a metal and has good handling efficiency, which liquid composition comprises a fluoropolymer having sulfonic acid functional groups and a solvent, wherein the solvent contains a polyhydric alcohol and a monohydric alcohol. The content of the fluoropolymer is preferably from 5 to 50 mass % in the liquid composition (100 mass %), and the content of the polyhydric alcohol is preferably from 5 to 50 mass % in the solvent (100 mass %).
1. A liquid composition comprising a fluoropolymer having sulfonic acid functional groups and a solvent, wherein the solvent comprises, based on 100 mass % of the solvent, from 5 to 50 mass % of at least one dihydric alcohol and from 50 to 95 mass % of at least one monohydric alcohol, and wherein the water content in the liquid composition is at most 0.5 mass %.
2. The liquid composition according to claim 1 , wherein the content of the fluoropolymer is from 5 to 50 mass %, based on 100 mass % of the liquid composition.
3. The liquid composition according to claim 1 , wherein the content of the solvent is from 50 to 95 mass %, based on 100 mass % of the liquid composition.
4. The liquid composition according to claim 1 , wherein the dihydric alcohol is one member selected from the group consisting of ethylene glycol, 1,2-propanediol and 1,3-propanediol, and the monohydric alcohol is ethanol.
5. The liquid composition according to claim 4 , wherein the dihydric alcohol is ethylene glycol.
6. The liquid composition according to claim 4 , wherein the dihydric alcohol is 1,2-propanediol.
7. The liquid composition according to claim 4 , wherein the dihydric alcohol is 1,3-propanediol.
8. The liquid composition according to claim 1 , wherein the fluoropolymer is a copolymer having constituting units based on a monomer represented by the following formula (1) and constituting units based on a monomer represented by the following formula (2), or a copolymer obtained by hydrolyzing the above copolymer to convert W to a sulfonic acid group:
CF 2 ═CX a X b (1)
CF 2 ═CF(OCF 2 CFX d ) s O(CF 2 ) t W (2)
wherein each of X a and X b is independently a fluorine atom, a chlorine atom, a hydrogen atom or a trifluoromethyl group, X d is a fluorine atom or a trifluoromethyl group, s is an integer of from 0 to 2, t is an integer of from 1 to 3, and W is a precursor group which can be converted to a sulfonic acid group by hydrolysis.
9. The liquid composition according to claim 8 , wherein the monomer represented by the formula (1) is CF 2 ═CF 2 , and the monomer represented by the formula (2) is CF 2 ═CFOCF 2 CF(CF 3 )OCF 2 CF 2 CF 2 SO 2 F.
10. The liquid composition according to claim 1 , wherein the ion-exchange capacity of the fluoropolymer is from 0.8 to 1.3 meq/g dry resin.
11. The liquid composition according to claim 1 , wherein the dihydric alcohol is present in an amount of from 20 to 50 mass % and the monohydric alcohol is present in an amount of 50 to 80 mass %, based on 100 mass % of the solvent.
12. The liquid composition according to claim 1 , wherein an organic solvent other than said solvent may be present in an amount no greater than 5 mass %, based on 100 mass % of the liquid composition.
13. The liquid composition according to claim 12 , wherein an organic solvent other than said solvent is present and is a ketone, an ether or an ester.
14. The liquid composition according to claim 1 , wherein the ion-exchange capacity of the fluoropolymer is from 0.9 to 1.2 meq/g dry resin.
15. The liquid composition according to claim 1 , wherein the content of the solvent is from 75 to 95 mass %, based on 100 mass % of the liquid composition.
16. The liquid composition according to claim 1 , wherein the water content is no greater than 0.0965 mass %.