Aqueous surfactant-free base coating for metallized paper

Claim 2

An aqueous coating, which consists essentially of a surfactant-free aqueous emulsion containing a film-forming polymer composite prepared by emulsion copolymerizing an acrylate monomer having a theoretical Tg of -55° to -70°C with a vinyl polymerizable monomer having a theoretical Tg of +50° to +110°C selected from the group consisting of a methacrylate ester, styrene, or styrene derivative to give an acrylate-containing polymer having a theoretical Tg of above -10° to +45°C, the polymerization being carried out in the presence of 25-40% by weight, based on the total weight of the monomers, of a fully neutralized colloid polymer soluble in water and having an actual Tg of +14° to +80°C, the colloid polymer being an ammonium salt of an acid-containing polymer having a number average molecular weight of 2000-10,000 and consisting essentially of 10-40% by weight of acrylic acid, methacrylic acid, or mixtures thereof and 60-90% of a vinyl polymerizable monomer selected from the group consisting of an acrylate ester, methacrylate ester, styrene, styrene derivative, and ethylene, the monomer percentages being by weight and totaling 100%, the polymer composite being present in the aqueous coating in an amount sufficient to form a film coating on a paper substrate as a base coating for vacuum metallization; the vacuum metallized base coating being characterized by a balanced combination of alkali removability, waterresistance, blockresistance, gloss, and metal adhesion.

Claim 3

An aqueous coating, which consists essentially of a surfactant-free aqueous emulsion containing a film-forming polymer composite prepared by emulsion copolymerizing an acrylate monomer having a theoretical Tg of -55° to -70°C with a vinyl polymerizable monomer having a theorical Tg of +50° to +110°C selected from the group consisting of a methacrylate ester, styrene, or styrene derivative to give an acrylate-containing polymer having a theoretical Tg of above -10° to +45°C, with the proviso that the acrylate-containing polymer is not a polymer of 43% butyl acrylate and 57% methyl methacrylate, the polymerization being carried out in the presence of 25-40% by weight, based on the total weight of the monomers, of a fully neutralized colloid polymer soluble in water and having an actual Tg of +14° to +80°C, the colloid polymer being an ammonium salt of an acid-containing polymer having a number average molecular weight of 2000-10,000 and consisting essentially of 10-40% by weight of acrylic acid, methacrylic acid, or mixtures thereof and 60-90% of a vinyl polymerizable monomer selected from the group consisting of an acrylate ester, methacrylate ester, styrene, styrene derivative, and ethylene, the monomer percentages being by weight and totaling 100%, with the proviso that the colloid polymer is not a polymer of 43% butyl acrylate, 43% methyl methacrylate, and 14% acrylic acid; the polymer composite being present in the aqueous coating in an amount sufficient to form a film coating on a paper substrate as a base coating for vacuum metallization; the vacuum metallized base coating being characterized by a balanced combination of alkali removability, waterresistance, blockresistance, gloss, and metal adhesion.

Claim 4

An aqueous coating, which consists essentially of a surfactant-free aqueous emulsion containing a film-forming polymer composite prepared by emulsion copolymerizing an acrylate monomer having a theoretical Tg of -55° to -70°C with a vinyl polymerizable monomer having a theorical Tg of +50° to +110°C selected from the group consisting of a methacrylate ester, styrene, or styrene derivative to give an acrylate-containing polymer having a theoretical Tg of above -10° to +45°C, with the proviso that the acrylate-containing polymer is not a polymer of 43% butyl acrylate and 57% methyl methacrylate, the polymerization being carried out in the presence of 25-40% by weight, based on the total weight of the monomers, of a fully neutralized colloid polymer soluble in water and having an actual Tg of +14° to +80°C, the colloid polymer being an ammonium salt of an acid-containing polymer having a number average molecular weight of 2000-10,000 and consisting essentially of 10-40% by weight of acrylic acid, methacrylic acid, or mixtures thereof and 60-90% of a vinyl polymerizable monomer selected from the group consisting of an acrylate ester, methacrylate ester, styrene, styrene derivative, and ethylene, the monomer percentages being by weight and totaling 100%, with the proviso that the colloid polymer is not a polymer of 43% butyl acrylate, 43% methyl methacrylate, and 14% acrylic acid; the polymer composite being present in the aqueous coating in an amount sufficient to form a film coating on a paper substrate as a base coating for vacuum metallization; the vacuum metallized base coating being characterized by a balanced combination of alkali removability, waterresistance, blockresistance, gloss, and metal adhesion.

Claim 5

The coating of Claim 1, wherein the polymer composite is present in an amount of 20-50% by weight and wherein the acrylate monomer is butyl acrylate or 2-ethylhexyl acrylate and the acrylate-containing polymer has the Tg of above -10° to +25°C.

Claim 6

4 . The coating of Claim 3, wherein the acrylate-containing polymer has the Tg of about -5° to +15°C and comprises 35-50% of the acrylate monomer and 50-65% of the vinyl polymerizable monomer, the vinyl polymerizable monomer being selected from the group consisting of styrene, methyl methacrylate, isobutyl methacrylate and mixtures thereof.

Claim 7

The coating of Claim 4, wherein the acrylate-containing polymer is 45% butyl acrylate and 55% methyl methacrylate; 50% butyl acrylate and 50% methyl methacrylate; 40% 2-ethylhexyl acrylate and 60% styrene; 40% 2-ethylhexyl acrylate and 60% methyl methacrylate; 50% butyl acrylate, 25% methyl methacrylate, and 25% styrene; 50% butyl acrylate, 25% methyl methacrylate, and 25% isobutyl methacrylate; or 40% 2-ethylhexyl acrylate, 30% methyl methacrylate, and 30% styrene, the acrylate- containing polymers having a Tg of -6 to +25°C.

Claim 8

The coating of Claim 1, wherein the colloid polymer has a Tg of +30° to +80°C and molecular weight of 2000-6000.

Claim 9

The coating of Claim 6, wherein the colloid polymer is 14% acrylic acid 43%, isobutyl methacrylate, and 43% methyl methacrylate; 35% acrylic acid and 65% styrene; or 20% acrylic acid and 80% ethylene.

Claim 10

The coating of Claim 1, wherein the film-forming polymer composite consists essentially of the acrylate-containing polymer of 40-50% butyl acrylate or 2-ethylhexyl acrylate and 50-60% of styrene, methyl methacrylate, isobutyl methacrylate, or mixtures thereof having a Tg of -10° to + 15°C and of the colloid polymer which is the ammonium salt of 10-40% of acrylic acid or methacrylic acid and 60-90% of styrene, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, methyl methacrylate, ethylene and mixtures thereof, the colloid polymer having a Tg of +30 to +80°C.

Claim 11

The coating of Claim 8, wherein the acrylate-containing polymer has a Tg of -5° to +10°C and the colloid polymer has a Tg of about +80°C and a molecular weight of about 3000.

Claim 12

1 0. In a process for the vacuum metallization of a paper substrate, wherein the paper substrate is passed into a high-vacuum metallization chamber in which a metallic vapor is deposited upon the paper substrate, the steps of: (a) first applying, to a surface of the paper substrate to be metallized, a coating of the aqueous base coating of Claim 1 in an amount sufficient to form a continuous, smooth film of said polymer composite sufficient to cover substantially all fibrous paper material projecting from said surface; (b) drying said coated paper substrate to substantially remove said water and ammonia from said ammonium salt; and (c) metallizing the surface of said dried, coated paper substrate.

Claim 13

11 . A metallized paper product, which comprises a paper substrate coated on at least one side thereof with a smooth, continuous coating of the aqueous base coating of Claim 1, dried, and overcoated with a thin metallic layer applied by vacuum metallization.