Aqueous fluoroelastomer curable composition and coated article

Abstract

An aqueous fluoroelastomer curable composition having an aqueous fluoroelastomer dispersion and a basic polyol curing agent, and an article having a coating film formed from this composition. The aqueous fluoroelastomer curable composition has a long pot life although it is a one-fluid type aqueous dispersion, and forms a cured film having sufficient strength and heat resistance at a relatively low temperature in a short time.

1 . An aqueous fluoroelastomer curable coating composition comprising: 
 an aqueous fluoroelastomer dispersion;    a basic polyol curing agent;    a curing accelerator selected from the group consisting of salts of tertiary amines of the formula NR 3  with inorganic or organic acids and salts of tertiary amines of the formula R 2 N—R′— NR 2  with inorganic or organic acids; and    optionally at least one fluoropolymer selected from the group consisting of a fluororesin and a terminal-modified perfluoropolyester; 
 wherein each of the R groups in either formula for the curing accelerator is the same or different from each other and each is an alkyl or alkenyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, or two or more R groups together form a carbon ring or a heterocyclic group, and  
 R′ is an alkylene group having 2 to 21 carbon atoms or a phenylenedialkylene group having 8 to 12 carbon atoms.  
   
     
     
         2 . The aqueous fluoroelastomer curable composition according to  claim 1 , wherein said basic polyol curing agent is a salt of a polyol having a phenyl group and at least two hydroxyl groups with a basic compound.  
     
     
         3 . The aqueous fluoroelastomer curable composition according to  claim 1 , wherein said basic polyol curing agent is a salt of a polyol having a phenyl group and at least two hydroxyl groups with at least one basic compound selected from the group consisting of ammonium, phosphonium, alkali metals and alkaline earth metals.  
     
     
         4 . The aqueous fluoroelastomer curable composition according to  claim 1 , wherein said basic polyol curing agent is a salt of at least one polyol selected from the group consisting of hydroquinone, bisphenol A, bisphenol AF and resol type phenolic resins and at least one basic compound selected from the group consisting of ammonium, phosphonium, alkali metals and alkaline earth metal.  
     
     
         5 . The aqueous fluoroelastomer curable composition according to  claim 1 , wherein said fluoroelastomer is an elastic copolymer of vinylidene fluoride and at least one other ethylenically unsaturated fluorine-containing monomer copolymerizable therewith.  
     
     
         6 . The aqueous fluoroelastomer curable composition according to  claim 1 , wherein said aqueous fluoroelastomer dispersion in said coating composition comprises a fluorine-containing elastic copolymer having repeating units represented by the formula: —CH 2 — in the backbone.  
     
     
         7 . The aqueous fluoroelastomer curable composition according to  claim 1 , said aqueous fluoroelastomer curable composition comprises said fluororesin.  
     
     
         8 . The aqueous fluoroelastomer curable composition according to  claim 7 , wherein said fluororesin is a tetrafluoroethylene base polymer.  
     
     
         9 . The aqueous fluoroelastomer curable composition according to  claim 7 , wherein said fluororesin is a copolymer of tetrafluoroethylene with at least one monomer selected from the group consisting of hexafluoropropylene and a perfluoroalkyl vinyl ether.  
     
     
         10 . The aqueous fluoroelastomer curable composition according to  claim 1 , said aqueous fluoroelastomer curable composition comprises said terminal-modified perfluoropolyether.  
     
     
         11 . The aqueous fluoroelastomer curable composition according to  claim 7 , said aqueous fluoroelastomer curable composition comprises the terminal-modified perfluoropolyether.  
     
     
         12 . An article wherein at least a part of the surface of said article is coated with a coating layer formed from the aqueous fluoroelastomer curable coating composition according to  claim 1 , wherein said coating layer is further coated with a non-tacky layer of fluororesin.  
     
     
         13 . An article wherein at least a part of the surface of said article is coated with a coating layer formed from the aqueous fluoroelastomer curable coating composition according to  claim 7 , wherein said coating layer is further coated with a non-tacky layer of fluororesin.  
     
     
         14 . An article wherein at least a part of the surface of said article is coated with a coating layer formed from the aqueous fluoroelastomer curable coating composition according to  claim 10 , wherein said coating layer is further coated with a non-tacky layer of fluororesin.