Coating composition, method for manufacturing film using the same, and coated article using the same

Abstract

A chromium-free fluoropolymer-containing primer composition, which can provide a coated article having excellent higher corrosion resistance by forming a fluoropolymer coating film, and a primer layer having sufficient adhesive strength to the fluoropolymer coating film on the surface of a substrate such as metal, glass, ceramic and heat resistant plastics, a method for manufacturing a coating film using the same, and a coated article using the same. The coating composition contains at least one kind of a fluoropolymer component selected from a reactive functional group-containing fluoropolymer, and a fluoropolymer having a melt flow rate (MFR), measured under a load of 5 kg and at 372° C., in accordance with ASTM D1238, of 10 to 100 g/10 minutes, and an organic titanate, wherein content of titanium contained in the organic titanate, relative to the fluoropolymer component, is 1 to 40% by weight.

1 . A coating composition, which comprises at least one kind of a fluoropolymer component selected from a fluoropolymer containing a reactive functional group, and a fluoropolymer having a melt flow rate (MFR) measured under a load of 5 kg and at 372° C. in accordance with ASTM D1238, of 10 to 100 g/10 minutes, and an organic titanate, wherein content of titanium contained in the organic titanate, relative to the fluoropolymer component, is 1 to 40% by weight. 
     
     
         2 . The coating composition according to  claim 1 , wherein the organic titanate is alkoxy titanium, titanium acylate, or titanium chelate which has a structure containing Ti—O—C bond formed by Ti(IV) or Ti(III), and a compound having an alcoholic hydroxyl group, a phenolic hydroxyl group or a carboxyl group. 
     
     
         3 . The coating composition according to  claim 2 , wherein the organic titanate is titanium diisopropoxybis(triethanolaminate). 
     
     
         4 . The coating composition according to  claim 1 , wherein the fluoropolymer is a polymer of a monomer selected from tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, fluoroalkoxytrifluoroethylene, vinylidene fluoride and vinyl fluoride, or a copolymer of the monomer and ethylene, or a copolymer of a compound having a reactive functional group and a fluorine-containing comonomer. 
     
     
         5 . The coating composition according to  claim 4 , wherein the fluoropolymer is at least one kind selected from a tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer (PFA), a tetrafluoroethylene/hexafluoropropylene copolymer (FEP), a ethylene/tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (CTFE), and polyvinilidene fluoride (PVDF). 
     
     
         6 . The coating composition according to  claim 1 , wherein the reactive functional group-containing fluoropolymer is a copolymer of a tetrafluoroethylene/a monomer having a reactive functional group/a fluorine-containing comonomer. 
     
     
         7 . The coating composition according to  claim 6 , wherein the compound having a reactive functional group is a phosphate ester compound containing trifluorovinyl ether group. 
     
     
         8 . The coating composition according to  claim 7 , wherein the phosphate ester compound containing trifluorovinyl ether group is a dihydrogenphophate ester compound represented by the following formula (3):
   CF 2 ═CF(OR) M (CH 2 )OP(O)(OH) 2   (3)
   (wherein R represents a perfluoroalkyl group or a perfluoroalkoxyl group, having carbon atoms of 1 to 20; and m is an integer of 1 to 10. When m is 2 or more, R may be the same or different, respectively).   
     
     
         9 . The coating composition according to  claim 6 , wherein the fluorine-containing comonomer is perfluoro(alkyl vinyl ether) or perfluoro(alkylvinyl). 
     
     
         10 . The coating composition according to  claim 1 , wherein the fluoropolymer component is a mixture of the fluoropolymer and 0 to 99% by weight of the reactive functional group-containing fluoropolymer, relative to the fluoropolymer. 
     
     
         11 . A method for manufacturing a coated article obtained by coating the coating composition according to  claim 1  on a substrate, removing a liquid solvent, and then baking to form a coating film. 
     
     
         12 . A coated article manufactured by the method according to  claim 11 , wherein average thickness of the film formed on the substrate is 1 to 300 μm. 
     
     
         13 . A coated article comprising a structure where the film according to  claim 12  is used as a primer layer, and at least one layer of a fluoropolymer or layer mainly comprising the fluoropolymer is formed on said primer, in an average thickness of 2 to 5000 μm. 
     
     
         14 . The coated article according to  claim 13 , wherein a layer containing a fluoropolymer and a polyphenylene sulfide resin is formed; as an intermediate layer, between the primer layer and the outermost layer. 
     
     
         15 . The coated article according to  claim 12 , wherein the substrate is any one of metal, ceramic, stainless steel, glass and heat resistant plastics. 
     
     
         16 . The coated article according to  claim 13 , wherein the substrate is any one of metal, ceramic, stainless steel, glass and heat resistant plastics.