Antibacterial lead-free cationic electrodeposition coating composition

Abstract

The present invention provides an antibacterial lead-free cationic electrodeposition coating composition comprising an aqueous medium, a binder resin including a cationic epoxy resin and a blocked isocyanate curing agent which is dispersed or dissolved in the aqueous medium, a neutralizing acid for neutralizing the cationic epoxy resin, an organic solvent and an antibacterial agent, wherein a volatile organic content is not more than 2% by weight, and the antibacterial agent is an isothiazolone compound. The antibacterial lead-free cationic electrodeposition coating composition of the present invention has reduced VOC and lead ion content in order to exert small influence on the environment, whereas having antibacterial ability comparable to that before reducing VOC and lead ion content, and having excellent electrodeposition performance.

What is claimed is:  
     
         1 . An antibacterial lead-free cationic electrodeposition coating composition comprising an aqueous medium, a binder resin including a cationic epoxy resin and a blocked isocyanate curing agent which is dispersed or dissolved in the aqueous medium, a neutralizing acid for neutralizing the cationic epoxy resin, an organic solvent and an antibacterial agent, 
 wherein a volatile organic content is not more than 2% by weight, and the antibacterial agent is an isothiazolone compound.    
     
     
         2 . The cationic electrodeposition coating composition according to  claim 1 , wherein said isothiazolone compound is chloromethyl isothiazolone, methyl isothiazolone, octyl isothiazolone or a mixture of two or more kinds of these.  
     
     
         3 . The cationic electrodeposition coating composition according to  claim 1 , wherein said isothiazolone compound is comprised in an amount of 2 to 100 ppm.  
     
     
         4 . The cationic electrodeposition coating composition according to  claim 1 , wherein hydrophilic organic solvent having antibacterial activity is comprised in an amount of not more than 1% by weight.  
     
     
         5 . The cationic electrodeposition coating composition according to  claim 1 , wherein said neutralizing acid is one or more kind selected from the group consisting of acetic acid, lactic acid, formic acid and sulfamic acid.  
     
     
         6 . The cationic electrodeposition coating composition according to  claim 1 , wherein a pigment is further comprised in an amount to that the weight ratio of pigment to resin solid contained in the coating composition is in the range of 1/80 to 1/1.  
     
     
         7 . An antibacterial agent comprising an isothiazolone compound, wherein the antibacterial agent is used for preventing microorganisms from breeding in a lead-free electrodeposition coating composition having a volatile organic content of not more than 2% by weight.  
     
     
         8 . The antibacterial agent according to  claim 7 , wherein said isothiazolone compound is chloromethyl isothiazolone, methyl isothiazolone, octyl isothiazolone or a mixture of two or more kinds of these.  
     
     
         9 . The antibacterial agent according to  claim 8 , wherein said isothiazolone compound is used in an amout of 2 to 100 ppm in the lead-free electrodeposition coating composition.  
     
     
         10 . Use of an isochiazolone compound for preventing microorganisms from breeding in a lead-free electrodeposition coating composition having a volatile organic content of not more than 2% by weight.  
     
     
         11 . The use according to  claim 10 , wherein said isothiazolone compound is chloromethyl isothiazolone, methyl isothiazolone, octyl isothiazolone or a mixture of two or more kinds of these.  
     
     
         12 . The use according to  claim 11 , wherein the amount of the isothiazolone compound is 2 to 100 ppm in the lead-free electrodeposition coating composition.