Liquid fluoropolymer composition, process for producing organosol, film, and fuel cell

Abstract

The invention provides a fluoropolymer liquid composition comprising a fluoropolymer and a film-forming auxiliary, said fluoropolymer comprising acid/acid salt fluorovinyl ether units represented by the general formula (I): said film-forming auxiliary being an organic liquid which is compatible with water and has a boiling point higher than 100° C. but not higher than 300° C., said fluoropolymer liquid composition being a fluoropolymer dispersion composition comprising said film-forming auxiliary and a fluoropolymer fine particle comprising said fluoropolymer, said fluoropolymer fine particle containing, at the proportion of at least 25% by mass thereof, a spherical fluoropolymer fine particle, and said spherical fluoropolymer fine particle being substantially spherical.

1 . A fluoropolymer liquid composition comprising a fluoropolymer and a film-forming auxiliary, 
 said fluoropolymer comprising an acid/acid salt fluorovinyl ether unit represented by the general formula (I):                          (wherein Y 1  represents a halogen atom or a perfluoroalkyl group, n represents an integer of 0 to 3, and n atoms/groups of Y 1  may be the same or different; Y 2  represents a halogen atom, m represents an integer of 1 to 5, and m atoms of Y 2  may be the same or different; and A 1  represents —SO 2 X 1  or —COOZ 1 , in which X 1  represents —OH, —ONR 1 R 2 R 3 R 4 , —NR 5 R 6  or —OM 1   1/L , R 1 , R 2 , R 3  and R 4  may be the same or different and each represents a hydrogen atom or an alkyl group containing 1 to 4 carbon atoms, R 5  and R 6  are the same or different and each represents a hydrogen atom, an alkali metal, an alkyl group or a sulfonyl-containing group, Z 1  represents a hydrogen atom, NR 7 R 8 R 9 R 10  or —M 2   1/L , R 7 , R 8 , R 9  and R 10  may be the same or different and each represents a hydrogen atom or an alkyl group containing 1 to 4 carbon atoms, M 1  and M 2  each represents a metal whose valence is L, and said metal whose valence is L is a metal belonging to the group 1, 2, 4, 8, 11, 12 or 13 of the periodic table),    said film-forming auxiliary being an organic liquid which is compatible with water and has a boiling point higher than 100° C. but not higher than 300° C.,    said fluoropolymer liquid composition being a fluoropolymer dispersion composition comprising said film-forming auxiliary and a fluoropolymer fine particle comprising said fluoropolymer,    said fluoropolymer fine particle containing, at the proportion of at least 25% by mass thereof, a spherical fluoropolymer fine particle, and    said spherical fluoropolymer fine particle being substantially spherical.    
   
   
       2 . The fluoropolymer liquid composition according to  claim 1 , 
 wherein the film-forming auxiliary is incorporated in an amount of 0.1 to 100 parts by mass per part by mass of the fluoropolymer.    
   
   
       3 . The fluoropolymer liquid composition according to  claim 1 , 
 wherein the film-forming auxiliary is a phosphoric acid ester.    
   
   
       4 . The fluoropolymer liquid composition according to  claim 1 , 
 wherein the film-forming auxiliary is a cyclic amide or a cyclic-amide derivative.    
   
   
       5 . The fluoropolymer liquid composition according to  claim 1 , 
 wherein the film-forming auxiliary is an ethylene oxide oligomer monohydroxy ether.    
   
   
       6 . The fluoropolymer liquid composition according to  claim 1 , 
 wherein the fluoropolymer is a binary or multinary copolymer comprising the acid/acid salt fluorovinyl ether unit and an ethylenic monomer-derived ethylenic monomer unit.    
   
   
       7 . The fluoropolymer liquid composition according to  claim 6 , wherein the ethylenic monomer is tetrafluoroethylene.  
   
   
       8 . The fluoropolymer liquid composition according to  claim 1 , 
 wherein Y 1  is trifluoromethyl group, Y 2  is a fluorine atom, n is 0 or 1 and m is 2.    
   
   
       9 . The fluoropolymer liquid composition according to  claim 8 , wherein n is 0.  
   
   
       10 . The fluoropolymer liquid composition according to  claim 1 , 
 wherein the fluoropolymer amounts to 1 to 60% by mass of said fluoropolymer liquid composition.    
   
   
       11 . The fluoropolymer liquid composition according to  claim 1 , 
 wherein the fluoropolymer is obtained by hydrolysis treatment of an emulsion polymer dispersion obtained from a fluorovinyl-ether derivative represented by the general formula (II):      CF 2 ═CF—O—(CF 2 CFY 1 —O) n —(CFY 2 ) m -A 2    (II)    (wherein Y 1  represents a halogen atom or a perfluoroalkyl group, n represents an integer of 0 to 3, and n atoms/groups of Y 1  may be the same or different; Y 2  represents a halogen atom, m represents an integer of 1 to 5, and m atoms of Y 2  may be the same or different; and A 2  represents a —SO 2 X 2  or —COZ 2  in which X 2  represents a halogen atom and Y 2  represents an alkoxy group containing 1 to 4 carbon atoms) by emulsion polymerization.    
   
   
       12 . The fluoropolymer liquid composition according to  claim 1 , 
 wherein the fluoropolymer fine particle contains, at the proportion of at least 50% by mass thereof, a spherical fluoropolymer fine particle, and    said spherical fluoropolymer fine particle is substantially spherical.    
   
   
       13 . The fluoropolymer liquid composition according to  claim 1 , 
 wherein the spherical fluoropolymer fine particle has an average particle diameter of not smaller than 10 nm.    
   
   
       14 . The fluoropolymer liquid composition according to  claim 1 , 
 wherein the fluoropolymer dispersion composition is a dispersion obtained by incorporating the film-forming auxiliary into fluoropolymer aqueous dispersion comprising the fluoropolymer fine particle dispersed in an aqueous dispersion medium.    
   
   
       15 . The fluoropolymer liquid composition according to  claim 14 , 
 wherein the film-forming auxiliary amounts to 10 to 99% by mass relative to the total mass of said film-forming auxiliary and the aqueous dispersion medium.    
   
   
       16 . The fluoropolymer liquid composition according to  claim 1 , 
 which further comprises a lower alcohol as well as the fluoropolymer and the film-forming auxiliary.    
   
   
       17 . The fluoropolymer liquid composition according to  claim 16 , 
 wherein the lower alcohol is incorporated in an amount of 0.5 to 5 parts by mass per part by mass of the fluoropolymer.    
   
   
       18 . The fluoropolymer liquid composition according to  claim 1 , 
 which is an organosol comprising the fluoropolymer fine particle dispersed in an organic medium,    wherein said organic medium comprises the film-forming auxiliary,    said organic medium further contains water or does not contains water and    said water amounts to not more than 10% by mass relative to said organic medium.    
   
   
       19 . The fluoropolymer liquid composition according to  claim 18 , 
 wherein the organic medium further comprises a lower alcohol.    
   
   
       20 . A fluoropolymer liquid composition according to  claim 19 , 
 wherein the lower alcohol is incorporated in an amount of 0.5 to 5 parts by mass per part by mass of the fluoropolymer.    
   
   
       21 . A method of producing an organosol, 
 which is for obtaining the fluoropolymer liquid composition according to  claim 18 , from fluoropolymer aqueous dispersion comprising the fluoropolymer fine particle dispersed in an aqueous dispersion medium, and    which comprises incorporating a film-forming auxiliary into said fluoropolymer aqueous dispersion, followed by water evaporation.    
   
   
       22 . A film/membrane obtainable by cast film formation using the fluoropolymer liquid composition according to  claim 1 .  
   
   
       23 . A film/membrane obtainable by impregnating a porous support with the fluoropolymer liquid composition according to  claim 1 , followed by removal of the liquid medium.  
   
   
       24 . An active substance-immobilized material comprising a fluoropolymer and an active substance, 
 said active substance-immobilized material being obtainable by applying, to a substrate, a liquid composition comprising the active substance and the fluoropolymer liquid composition according to  claim 1 .    
   
   
       25 . An electrolyte membrane comprising the active substance-immobilized material according to  claim 24 .  
   
   
       26 . A membrane/electrode assembly comprising the electrolyte membrane according to  claim 25 .  
   
   
       27 . A solid polymer electrolyte fuel cell comprising the film/membrane according to  claim 22 .  
   
   
       28 . A solid polymer electrolyte fuel cell comprising the film/membrane according to  claim 23 .  
   
   
       29 . A solid polymer electrolyte fuel cell comprising the active substance-immobilized material according to  claim 24 .  
   
   
       30 . A solid polymer electrolyte fuel cell comprising the electrolyte membrane according to  claim 25 .  
   
   
       31 . A solid polymer electrolyte fuel cell comprising the membrane/electrode assembly according to  claim 26.