Fast film formation water based barrier coating
View Patent ↗The invention relates to a composition which, when mixed with a polymer composition, allows for the formation of a continuous and cohesive film. The film is characterized in that it provides water, grease and oil resistance, provides a water vapor barrier and can used as wax replacement treatment and a top coat for flexible packaging, but also on other substrates. This film is formed at a very fast set speed without the need of thermal energy. The composition contains i) a salt of one or more of myristic, palmitic and stearic acid; and preferably also ii) a C 9 -C 18 fatty acid complex of a metal ion, the metal ion having an oxidation state of at least 3. The invention also provides processes and coated substrates.
1. A process for providing water, vapour, oil and grease resistance to a paper or paperboard material comprising:
I. combining a) a salt of one or more of myristic, palmitic and stearic acid, said salt being selected from the group consisting of sodium, potassium, calcium, and zinc salts; and b) a polymeric composition comprising a polymer, a copolymer, or mixtures of polymers or copolymers, in the presence of an aqueous solvent to form a liquid water-based film-forming composition;
II. Coating directly on a paper or paperboard surface of the paper or paperboard material with a liquid coating of said liquid film-forming composition; and
III. allowing a solid film of said polymeric composition to form from said liquid coating on the material at a temperature less than 50° C.
2. The process of claim 1 , wherein step I) further comprises combining a) and b) with c) a C 9 -C 18 fatty acid complex of a metal ion, said metal ion having an oxidation state of at least 3.
3. The process of claim 1 , wherein said solid film in step III is formed without direct heat in less than 1 minute.
4. The process of claim 1 , wherein said water-based film-forming composition is in the form of a dispersion, emulsion, solution, or suspension in which said aqueous solvent comprises at least 50% by volume of water.
5. The process of claim 4 , wherein said film-forming composition comprises 5 to 30% by weight of said salt, and 0 to 30% by weight of a filler, based on the weight of the water-based film-forming composition.
6. The process of claim 1 , wherein said solid film in step III is formed without added thermal or microwave energy.
7. The process of claim 1 , wherein said salt is calcium stearate or zinc stearate.
8. The process of claim 1 , wherein said solid film is formed at a temperature of 15 to 35° C.
9. The process of claim 3 , wherein said solid film is formed at a temperature of 15 to 35° C.
10. The process of claim 9 , wherein said water-based film-forming composition further comprises a tackifier resin.
11. The process of claim 10 , wherein said tackifier resin is a glycerol ester of hydrogenated rosin.
12. A process for providing water, vapour, oil and grease resistance to a paper or paperboard material comprising:
I. combining a) a salt of one or more of myristic, palmitic and stearic acid; b) a polymeric composition comprising a polymer, a copolymer, or mixtures of polymers or copolymers, and c a C 9 -C 18 fatty acid complex of a metal ion, said metal ion having an oxidation state of at least 3, in the presence of an aqueous solvent to form a water-based film-forming composition;
II. coating a surface of the paper or paperboard material with said film-forming composition; and
III. allowing a film of said polymeric composition to form on the material at a temperature less than 50° C.;
wherein said salt in a) is calcium stearate and said metal ion in c) is chromium ion, and a) and c) are in a ratio of 5:1 to 20:1.
13. The process of claim 12 , wherein said solid film in step III is formed without direct heat.
14. The process of claim 13 , wherein said solid film in step III is formed in less than 1 minute.