Multifunctional acrylate based abrasion resistant coating composition

Abstract

A radiation curable protective coating composition is disclosed which contains at least one multifunctional acrylate or methacrylate monomer and colloidal silica dispersed in water or an organic solvent/water mixture. When applied to a substrate and radiation cured, the composition forms a transparent abrasion resistant, weather resistant, ultraviolet light resistant, coating firmly held thereon.

That which is claimed is: 
     
       1. A radiation curable coating composition comprising: (A) from 30 to 99 percent, based on the total weight of the composition, of at least one multifunctional acrylate or methacrylate monomer; and   (B) from 1 to 70 percent, based on the total weight of the composition, of colloidal silica dispersed in water or in an organic solvent/water mixture.   
     
     
       2. The composition of claim 1 wherein component (A) is trimethylolpropanetriacrylate. 
     
     
       3. The composition of claim 1 wherein component (A) is a mixture of trimethylolpropanetriacrylate and hexanedioldiacrylate. 
     
     
       4. The composition of claim 1 wherein component (B) is a dispersion of colloidal silica in isopropanol and water. 
     
     
       5. The composition of claim 1 including a diluent selected from the group consisting of isopropanol, t-butanol, n-propanol, n-butanol, methanol, ethanol, ethylene glycol n-butyl ether, and mixtures thereof. 
     
     
       6. The composition of claim 5 wherein the diluent is present in an amount of from 40 to 85 percent, based on the total weight of the composition. 
     
     
       7. The composition of claim 5 wherein the diluent is present in an amount of from 53 to 78 percent, based on the total weight of the composition. 
     
     
       8. The composition of claim 1 which additionally contains one or more hindered amine light stabilizer. 
     
     
       9. The composition of claim 8 wherein the hindered amine light stabilizer is bis(1,2,2,6,6-pentamethyl-4-piperidinyl) [3,5-bis(1,1-dimethylethyl-4-hydroxyphenyl)methyl]-butylpropanedioate. 
     
     
       10. The composition of claim 1 which additionally contains one or more UV absorbers. 
     
     
       11. A composition of claim 10 wherein the UV absorber is 2,2',4,4'-tetrahydroxybenzophenone. 
     
     
       12. The composition of claim 1 which additionally contains one or more photoinitiators. 
     
     
       13. The composition of claim 12 wherein the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-propan-1-one. 
     
     
       14. The composition of claim 12 which additionally contains one or more oxygen inhibitors. 
     
     
       15. A composition of claim 14 wherein the oxygen inhibitor is 2-ethylhexyl-para-dimethylaminobenzoate.