Sunlight curable coating compositions

摘要

A coating composition capable of curing to a high hardness by exposure to sunlight. More particularly, the coating composition comprises a high molecular weight polyurethane (meth)acrylate or methacrylate dissolved in one or more non-alcohol solvent, a visible light photoinitiator, and an alcohol solubilizer.

主权项

1. A liquid, curable coating composition comprising in admixture:
(a) one or more polyurethane film-forming polymers having the formula
C-(D-[-(R-D)n-(P-D)m-]xE)k-C wherein: i) D is a residue of a diisocyanate group, ii) R is a residue of one or more diol or triol groups having a molecular weight less than or equal to 500 Daltons; iii) P is a residue of one or more oligomeric diol groups having a molecular weight of from about 500 Daltons to about 3000 Daltons; iv) E is a residue of a urea group having a molecular weight less than or equal to 500 Daltons; v) C is a residue of a monohydroxyl functional acrylate group or methacrylate group; wherein the equivalent ratio of (i) to (ii) is less than 1.5:1; and the equivalent ratio of (i) to (iii) is greater than 15:1; n=20 to 450, m=θ1 to 5, x=1 to 10, and k=1 to 10; b) an alcohol solubilizer; c) a non-alcohol solvent; (d) a photoinitiator in an amount sufficient to polymerize the polyurethane film-forming polymers when exposed to light energy having a wavelength of 395 nm or above at an energy level of about 1 J/cm2 or more.