Waterborne coating composition useful for promoting adhesion to plastic surfaces

Abstract

The waterborne coating composition herein is useful for promoting adhesion of paint to a component such as a plastic automobile part or accessory. The waterborne coating composition is particularly useful for promoting adhesion of paint to a thermoplastic polyolefin surface. The waterborne coating composition is prepared from a mixture comprising at least one chlorinated polyolefin resin and at least one urethane acrylic hybrid resin. The waterborne coating composition provides not only good adhesion of a paint to a thermoplastic polyolefin surface, but also provides good appearance. The waterborne coating composition is also compatible with a wide variety of paint systems and can be rapidly dried under ambient conditions.

What is claimed is: 
     
         1 . A waterborne coating composition for forming a paint adhesion-promoting coating on a plastic surface, the waterborne coating composition prepared from a mixture comprising:
 at least one chlorinated polyolefin resin in an amount effective to promote adhesion of the coating to a plastic surface; and   at least one urethane acrylic hybrid resin in an amount effective to counteract tackiness of the chlorinated polyolefin resin and promote rapid drying of the coating;   wherein the chlorinated polyolefin resin is present in the mixture at about 35.0 to 45.0 wt % based on total dry resin solids content; and   wherein the urethane acrylic hybrid resin is present in the mixture at about 55.0 to 65.0 wt % based on total dry resin solids content.   
     
     
         2 . The waterborne coating composition according to  claim 1 , wherein the coating formed by the waterborne coating composition is ready to have a paint layer applied thereon after drying for about 20 minutes or less under ambient conditions. 
     
     
         3 . The waterborne coating composition according to  claim 1 , wherein the mixture comprises a coalescent solvent. 
     
     
         4 . The waterborne coating composition according to  claim 3 , wherein the coalescent solvent comprises an ethylene glycol derivative and an alcohol ester. 
     
     
         5 . The waterborne coating composition according to  claim 1 , wherein the mixture comprises a surfactant. 
     
     
         6 . The waterborne coating composition according to  claim 1 , wherein the surfactant is present in a surfactant blend comprising a wetting agent and a leveling agent. 
     
     
         7 . A coating formed from a waterborne coating composition prepared from a mixture comprising:
 at least one chlorinated polyolefin resin in an amount effective to promote adhesion of the coating to a plastic surface,   at least one urethane acrylic hybrid resin in an amount effective to counteract tackiness of the chlorinated polyolefin resin and promote rapid drying of the coating, and   water,   wherein the chlorinated polyolefin resin is present in the mixture at about 35.0 to 45.0 wt % based on total dry resin solids content; and   wherein the urethane acrylic hybrid resin is present in the mixture at about 55.0 to 65.0 wt % based on total dry resin solids content.   
     
     
         8 . The coating according to  claim 7 , wherein the coating has a thickness of from about 0.01 mils to about 2.5 mils. 
     
     
         9 . The coating according to  claim 7 , wherein the coating is applied to a plastic substrate having a surface. 
     
     
         10 . The coating according to  claim 9 , wherein the coated plastic substrate is a plastic automotive component. 
     
     
         11 . The coating according to  claim 10 , wherein the plastic automotive component comprises an automotive paint. 
     
     
         12 . The coating according to  claim 10 , wherein the plastic automotive component is a bumper, a door, a fender, a body panel, a side-panel, a hood, a trunk, or a roof. 
     
     
         13 . The coating according to  claim 10 , wherein the plastic automotive component is formed at least partially from a thermoplastic olefin. 
     
     
         14 . A method of painting a plastic automotive component, comprising:
 applying, to at least a portion of a surface of a plastic automotive component, a waterborne coating composition to form an adhesion-promoting coating, the waterborne coating composition prepared from a mixture comprising:
 at least one chlorinated polyolefin resin in an amount effective to promote adhesion of the coating to a plastic surface, 
 at least one urethane acrylic hybrid resin in an amount effective to counteract tackiness of the chlorinated polyolefin resin and promote rapid drying of the coating, and 
 wherein the chlorinated polyolefin resin is present in the mixture at about 35.0 to 45.0 wt % based on total dry resin solids content; and 
 wherein the urethane acrylic hybrid resin is present in the mixture at about 55.0 to 65.0 wt % based on total dry resin solids content; and 
   painting the coated surface of the plastic automotive component with an automotive paint.   
     
     
         15 . The method according to  claim 14 , further comprising:
 cleaning at least a portion of the surface of the plastic automotive component to remove dust, debris and contaminants from the surface of the plastic automotive component; and   applying the waterborne coating composition on a cleaned portion of the surface.   
     
     
         16 . The method according to  claim 18 , further comprising drying the adhesion-promoting coating for about 20 minutes or less under ambient conditions prior to painting the coated surface with an automotive paint. 
     
     
         17 . The method according to  claim 18 , further comprising heating the adhesion-promoting coating for less than about 5 minutes. 
     
     
         18 . The method according to  claim 18 , wherein applying the waterborne coating composition comprises spraying, brushing or rolling. 
     
     
         19 . A method of making a waterborne coating composition for forming a coating that promotes adhesion of paint to plastic surfaces, comprising:
 mixing:   at least one chlorinated polyolefin resin in an amount effective to promote adhesion of the coating to a plastic surface, and   at least one urethane acrylic hybrid resin in an amount effective to counteract tackiness of the chlorinated polyolefin resin and promote rapid drying of the coating, and   water;   wherein the chlorinated polyolefin resin is present in the mixture at about 35.0 to 45.0 wt % based on total dry resin solids content;   wherein the urethane acrylic hybrid resin is present in the mixture at about 55.0 to 65.0 wt % based on total dry resin solids content.   
     
     
         20 . The method according to  claim 19 , wherein the chlorinated polyolefin resin is selected from the group consisting of chlorinated polyethylene, chlorinated polypropylene, chlorinated ethylene-propylene copolymer, chlorinated polyisobutylene, chlorinated polybutene, chlorinated ethylene-vinyl acetate copolymer, and a combination thereof.