Damage-preventive coatings

Claim 1

A structure comprising a hermetically sealed glass envelope, a combustion-supporting gas in said envelope, ignition means attached to said envelope and disposed in operative relationship to said combustible material, and a protective coating on the exterior surface of said envelope, characterized in that said protective coating comprises an addition-polymerized unsaturated resin composition, further characterized in that said addition-polymerized unsaturated resin composition, prior to curing, comprises an addition-polymerizable admixture comprising: (a) at least one addition-polymerizable resin selected from the group consisting of unsaturated urethane resin and unsaturated urea resin, such addition-polymerizable resin comprising the reaction product of (i) at least one organic isocyanate compound characterized by the presence of at least two reactive isocyanate groups; (ii) from 30 to 100 mol percent of at least one polymeric material characterized by the presence of at least two active hydrogen groups selected from hydroxyl, primary amine, secondary amine, and mixtures of such groups; (iii) from 70 to 0 mol percent of at least one monomeric chain-extending compound having at least two active hydrogen groups selected from hydroxyl, primary amine, secondary amine, and mixtures of such groups; and (iv) at least one addition-polymerizable monomeric compound having a single ethylenically unsaturated unit and a single isocyanate-reactive hydrogen group selected from hydroxyl, primary amine, and secondary amine; said isocyanate compound (i) being present in an amount sufficient to provide an NCO:active hydrogen group ratio of at least 1.05:1 with respect to the active hydrogen groups of (ii) and (iii); the mole percents of (ii) and (iii) being based on total mols of polymeric materials and monomeric materials having at least two active hydrogen groups; said addition-polymerizable monomeric compound (iv) being present in an amount to provide from 0.5 to 3 units of ethylenic unsaturation per 1,000 units of molecular weight of said addition-polymerizable resin; and (b) a reactive diluent system comprising at least one addition-polymerizable unsaturated monomeric compound which is copolymerizable with said addition-polymerizable resin, said reactive diluent system comprising from 10 to 100 percent by weight, based on total weight of diluent system of N-vinyl-2-pyrrolidone.