Multilayer Coating for Covering Vehicle Body Parts

Abstract

The invention further pertains to a method for manufacturing a multilayer coating for covering vehicle body parts.

1 . Multilayer coating for covering vehicle body parts, comprising a polymeric facestock layer ( 3 ) which is located between a polymeric top coat layer ( 4 ) and a polymeric adhesive layer ( 2 ), the top coat layer ( 4 ) comprising at least partially cross-linked polyurethane, characterized in that the at least partially cross-linked polyurethane is the reaction product of a composition comprising a first part and a second part, wherein:
 the first part comprises between 0.1 and 99.9 wt. % of solvent- or waterborne thermally curable polyurethane precursor material, as based on the total weight of said composition; and   the second part comprises between 0.1 and 99.9 wt. % of UV-curable polyurethane precursor material, as based on the total weight of said composition.   
     
     
         2 . Multilayer coating according to  claim 1 , wherein said composition comprises solvent- or waterborne polyurethane precursor material in an amount between 20.0 and 60.0 wt. % and UV-curable polyurethane precursor material in an amount between 40.0 and 80.0 wt. %, as based on the total weight of said composition. 
     
     
         3 . Multilayer coating according to  claim 1 , wherein the solvent- or waterborne thermally curable polyurethane precursor material comprises one or more polyester polyols, polycaprolactone polyols and/or polycarbonate polyols next to one or more polyoxyalkylene, polyester and/or polybutadiene compounds terminated by two or more isocyanate functional groups. 
     
     
         4 . Multilayer coating according to  claim 1 , wherein the UV-curable polyurethane precursor material comprises one or more acrylate polymers, diisocyanates, polyisocyanates, diols, polyols, diamines, polyamines, and/or one or more compounds containing one or more functional groups reactive towards isocyanate groups. 
     
     
         5 . Multilayer coating according to  claim 1 , wherein the facestock layer ( 3 ) comprises a thermoplastic polymer selected from the group comprising polyurethane, polyester and polyvinylchloride. 
     
     
         6 . Multilayer coating according to  claim 1  further comprising a protective layer ( 5 ) adjacent to the top coat layer ( 4 ) and opposite to the facestock layer ( 3 ). 
     
     
         7 . Multilayer coating according to  claim 1  further comprising a liner ( 1 ) adjacent to the adhesive layer ( 2 ) and opposite to the facestock layer ( 3 ). 
     
     
         8 . Multilayer coating according to  claim 1 , wherein the top coat layer ( 4 ) has a haze of less than 15% after 500 taber cycles, as measured at a wavelength ranging from 410 nm to 700 nm according to ASTM D-1003. 
     
     
         9 . Multilayer coating according to  claim 1 , wherein the top coat layer ( 4 ) has a spectral transmission of at least 80% at a wavelength ranging from 410 nm to 700 nm according to ASTM D-1003. 
     
     
         10 . Multilayer coating according to  claim 1 , wherein the top coat layer ( 4 ) has an elongation at break of at least 20% when measured according to ASTM D638-95. 
     
     
         11 . Multilayer coating according to  claim 1 , wherein the top coat layer ( 4 ) has a solvent resistance of at least 100 when measured by MEK double rubs in accordance with ASTM D5402. 
     
     
         12 . Method for manufacturing a multilayer coating for covering vehicle body parts, comprising the steps of:
 providing a polymeric facestock layer  3 ;   providing a polymeric adhesive layer  2 ;   providing a polymeric top coat layer  4 ;   sandwiching the facestock layer  3  between the top coat layer  4  and the adhesive layer  2 ,   wherein the step of providing the top coat layer  4  comprises the following steps:   a) adding thermally curable polyurethane precursor material to solvent or water to obtain a first dispersion or solution;   b) adding UV-curable polyurethane precursor material to the solvent- or waterborne polyurethane obtained in step a) to obtain a second dispersion or solution;   c) coating the mixture obtained in step 2 on the polymeric facestock  3 ;   d) heating the mixture once coated in such a way that water and/or solvent is evaporated and the polyurethane described in step a) is at least partially cross-linked;   e) Submitting the mixture resulting from step d) to UV radiation in such a way that the polyurethane described in step b) is at least partially cross-linked.   
     
     
         13 . Method according to  claim 12 , wherein the second dispersion comprises between 20.0 and 60.0 wt. % of said solvent- or waterborne thermally curable polyurethane and between 40.0 and 80.0 wt. % of said UV-curable polyurethane precursor material, as based on the total weight of said second dispersion.