Process for forming multi layered coated film and multi layered coated film

Abstract

The present invention provides a process for forming a multi layered coated film having good finished appearance. The present invention relates to a process for forming a multi layered coated film comprising the steps of conducting electrodeposition coating with a cationic electrodeposition coating composition on a substrate, and then heating and curing it to form an cured electrodeposition coated film on the substrate, applying an intermediate coating composition on the cured coated film to form an uncured intermediate coated film, applying a base top coating composition on the uncured intermediate coated film to form an uncured base coated film, applying a clear top coating composition on the uncured base coated film to form an uncured clear coated film, and simultaneously heating and curing the three uncured coated films, wherein the cured electrodeposition coated film has specified ranges of Ra and Pa; or has specified ranges of Tg and crosslinking density.

1 . A process for forming a multi layered coated film comprising the steps of: 
 conducting electrodeposition coating with a cationic electrodeposition coating composition on a substrate, and then heating and curing it to form an cured electrodeposition coated film on the substrate,    applying an intermediate coating composition on the cured electrodeposition coated film to form an uncured intermediate coated film,    applying a base top coating composition on the uncured intermediate coated film to form an uncured base coated film    applying a clear top coating composition on the uncured base coated film to form an uncured clear coated film, and    simultaneously heating and curing the uncured intermediate coated film, the uncured base top coated film and the uncured clear coated film; wherein    the cured electrodeposition coated film has a centerline average roughness (Ra) of 0.05 to 0.25 μm obtained from a roughness curve and a centerline average roughness (Pa) of 0.05 to 0.30 μm obtained from a profile curve.    
     
     
         2 . A process for forming a multi layered coated film comprising the steps of: 
 conducting electrodeposition coating with a cationic electrodeposition coating composition on a substrate, and then heating and curing it to form an cured electrodeposition coated film on the substrate,    applying an intermediate coating composition on the cured electrodeposition coated film to form an uncured intermediate coated film,    applying a base top coating composition on the uncured intermediate coated film to form an uncured base coated film    applying a clear top coating composition on the uncured base coated film to form an uncured clear coated film, and    simultaneously heating and curing the uncured intermediate coated film, the uncured base top coated film and the uncured clear coated film; wherein    the cured electrodeposition coated film has a surface energy of 37 to 43 mJ/m 2 , and the intermediate coating composition has a contact angle of 10 to 30 degrees on the cured electrodeposition coated film.    
     
     
         3 . A process for forming a multi layered coated film comprising the steps of: 
 conducting electrodeposition coating with a cationic electrodeposition coating composition on a substrate, and then heating and curing it to form an cured electrodeposition coated film on the substrate,    applying an intermediate coating composition on the cured electrodeposition coated film to form an uncured intermediate coated film,    applying a base top coating composition on the uncured intermediate coated film to form an uncured base coated film    applying a clear top coating composition on the uncured base coated film to form an uncured clear coated film, and    simultaneously heating and curing the uncured intermediate coated film, the uncured base top coated film and the uncured clear coated film; wherein    the cured electrodeposition coated film has a centerline average roughness (Ra) of 0.05 to 0.25 μm obtained from a roughness curve, a centerline average roughness (Pa) of 0.05 to 0.30 μm obtained from a profile curve and a surface energy of 37 to 43 mJ/m 2 , and the intermediate coating composition has a contact angle of 10 to 30 degrees on the cured electrodeposition coated film.    
     
     
         4 . A process for forming a multi layered coated film comprising the steps of: 
 conducting electrodeposition coating with a cationic electrodeposition coating composition on a substrate, and then heating and curing it to form an cured electrodeposition coated film on the substrate,    applying an intermediate coating composition on the cured electrodeposition coated film to form an uncured intermediate coated film,    applying a base top coating composition on the uncured intermediate coated film to form an uncured base coated film    applying a clear top coating composition on the uncured base coated film to form an uncured clear coated film, and    simultaneously heating and curing the uncured intermediate coated film, the uncured base top coated film and the uncured clear coated film; wherein    the cured electrodeposition coated film has a glass transition temperature Tg of 100 to 130° C. and a crosslinking density of 1.2 to 2.6 mmol/cc, obtained by dynamic viscoelastic measurement.    
     
     
         5 . The process for forming a multi layered coated film according to  claim 1 , wherein the intermediate coating composition comprises 
 an intermediate coating resin comprising at least one selected from the group comprising of acrylic resin, polyester resin and polyurethane resin    an intermediate coating curing agent comprising at least one selected from the group consisting of blocked isocyanate compound, oxazoline compound, carbodiimide compound and melamine compound, and    a pigment.    
     
     
         6 . The process for forming a multi layered coated film according to  claim 2 , wherein the intermediate coating composition comprises 
 an intermediate coating resin comprising at least one selected from the group comprising of acrylic resin, polyester resin and polyurethane resin    an intermediate coating curing agent comprising at least one selected from the group consisting of blocked isocyanate compound, oxazoline compound, carbodiimide compound and melamine compound, and    a pigment.    
     
     
         7 . The process for forming a multi layered coated film according to  claim 3 , wherein the intermediate coating composition comprises 
 an intermediate coating resin comprising at least one selected from the group comprising of acrylic resin, polyester resin and polyurethane resin    an intermediate coating curing agent comprising at least one selected from the group consisting of blocked isocyanate compound, oxazoline compound, carbodiimide compound and melamine compound, and    a pigment.    
     
     
         8 . The process for forming a multi layered coated film according to  claim 4 , wherein the intermediate coating composition comprises 
 an intermediate coating resin comprising at least one selected from the group comprising of acrylic resin, polyester resin and polyurethane resin    an intermediate coating curing agent comprising at least one selected from the group consisting of blocked isocyanate compound, oxazoline compound, carbodiimide compound and melamine compound, and    a pigment.