ES378484A1 - A procedure for obtaining coatings on enhanced, engraved or uncovered woods. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Wooden materials are coated with polyesters by applying a primer coating which comprises at least one salt of a metal of the fourth period of the periodic system having an atomic number 19-32 drying the primer coat applying a mixture comprising a polyester, a photochemically active sensitising agent and at least one peroxide catalyst of formula: in which R, is straight or branched chain aliphatic hydrocarbon radical, R 2 is methyl or phenyl, R 3 is hydrogen, a branched chain aliphatic hydrocarbon, a mixed aliphaticaromatic hydrocarbon with alkyl substituents in the aliphatic chain or an acyl group derived from an aliphatic carboxylic acid having its chain substituted by alkyl radicals, and in which n is 1 or 2 and then curing the coating with ultra violet light. The primer coating may comprise an unsaturated polyester or other synthetic resins or nitrocellulose and preferably contains 0.02-0.06% wt. of the activator which is suitably the salt of a metal with atomic number 21-30 in a high valency state, e.g. vanadium paratoluene sulphonate, copper sulphate, calcium octoate chromium trichloride. The primer may contain dyestuffs and/or carbon black and is suitably applied by staining, spraying or curtain coating. The top coating preferably contains 1.5-3.5% of the peroxide as well as other monomers, e.g. styrene and stabilisers such as hydroquinone. Specified peroxides are methyl isobutyl ketone peroxide, 2,5-dimethylhexane-2,5-dehydroperoxide t-butylhydroperoxide, cumene hydroperoxide, di-t-butyl hydroperoxide t-butylcumylperoxide t-butylcumylperoxide, dicumpl peroxide and t-butyl perisononate. Curing is best effected by U.V. light of energy in the range 350 to 380 nanometer.