Base coatings for use on vacuum metallized paper

摘要

Improved base coatings for use on paper substrates to be vacuum metallized consist essentially of an organic solvent solution (e.g. ethyl acetate or ethyl acetate/toluene) containing about 10-30 wt. % of a film-forming coating mixture of (a) about 90-98 wt. % of a vinyl acetate/acrylic acid copolymer (97.5-99/1-2.5%) or a vinyl acetate/monoethyl maleate copolymer (94-97/3-6%) and (b) about 2-10 wt. % of a soluble nitrocellulose resin solids, the resin being soluble in the solvent and having a nitrogen content of about 12 wt. % and a viscosity of from about 4-5 sec. in a 25% solution to about 3-4 sec. in a 20% solution of ethyl alcohol/toluene/ethyl acetate (25/55/20), when measured using the Falling Ball method. Paper products coated with the base coating (about 2-6 lbs./3000 ft.2) are characterized by a balanced combination of alkali removability, water-resistance, and block-resistance. The metallized products are smooth and glossy, and the aluminized product is especially useful for bottle labels.