Repulpable corrugated boxboard
View Patent ↗A coating composition for the linerboard of corrugated paperboard provides water and grease resistance but is water vapor permeable, and thus permits a different mode of manufacture of corrugated paperboard when aqueous adhesives are employed in the assembly of the linerboards and corrugated medium; in particular the linerboards may be coated with the coating composition prior to assembly of the corrugated paperboard because the water vapor permeable coating permits escape of the water of the aqueous adhesive, during drying of the assembled components of the corrugated paperboard; the coating composition employs a styrene-acrylate copolymer and a C 14 -C 18 fatty acid complex of a metal ion having an oxidation state of at least 3, such as chromium.
1. A repulpable coated paperboard liner for use in corrugated paperboard packaging manufacture comprising:
a) a paperboard sheet having opposed first and second surfaces,
b) a wax-free, water-resistant, grease resistant, water vapor permeable coating on at least one of said surfaces,
said coating consisting essentially of a styrene-acrylate copolymer and a C 14 -C 18 fatty acid complex of a metal ion having an oxidation state of at least 3.
2. A liner according to claim 1 , wherein said metal ion is trivalent chromium, said copolymer is a styrene-butyl acrylate copolymer, and said coating further comprises an inert particulate filler.
3. A liner according to claim 2 , wherein said coating has a dry coating weight of 5 to 25 g/m 2 .
4. A liner according to claim 3 , wherein said complex is a water soluble Werner complex and said fatty acid is tetradecanoic acid.
5. A liner according to claim 3 , wherein said filler comprises 10 to 15% by weight of said coating.
6. A liner according to claim 1 , wherein said complex is a water soluble Werner complex in which said metal ion is trivalent chromium and said fatty acid is tetradecanoic acid.
7. A liner according to claim 1 , wherein said complex is chromium pentahydroxy(tetradecanoato)di-.
8. A liner according to claim 1 , wherein said copolymer is a copolymer of styrene and an alkylacrylate in which the alkyl moiety has 1 to 6 carbon atoms.
9. A liner according to claim 8 , wherein said metal ion is an ion of iron, titanium, chromium or vanadium and said fatty acid is tetradecanoic acid or stearic acid.
10. A repulpable coated paperboard for packaging comprising:
a) a paperboard sheet having opposed first and second surfaces,
b) a wax-free, water-resistant, grease resistant, water vapor permeable coating on at least one of said surfaces,
said coating consisting essentially of a styrene-acrylate copolymer and a C 14 -C 18 fatty acid complex of a metal ion having an oxidation state of at least 3.
11. A paperboard according to claim 10 , wherein said metal ion is trivalent chromium, said copolymer is a styrene-butyl acrylate copolymer, and said coating further comprises an inert particulate filler.
12. A paperboard according to claim 11 , wherein said filler comprises 10 to 15% by weight of said coating.
13. A paperboard according to claim 11 , wherein said coating has a dry coating weight of 5 to 25 g/m 2 .
14. A paperboard according to claim 13 , wherein said complex is a water soluble Werner complex and said fatty acid is tetradecanoic acid.
15. A paperboard according to claim 13 , wherein said filler comprises 10 to 15% by weight of said coating.
16. A paperboard according to claim 10 , wherein said complex is a water soluble Werner complex in which said metal ion is trivalent chromium and said fatty acid is tetradecanoic acid.
17. A paperboard according to claim 10 , wherein said complex is chromium pentahydroxy(tetradecanoato)di-.
18. A paperboard according to claim 10 , wherein said copolymer is a copolymer of styrene and an alkylacrylate in which the alkyl moiety has 1 to 6 carbon atoms.
19. A paperboard according to claim 18 , wherein said metal ion is an ion of iron, titanium, chromium or vanadium and said fatty acid is tetradecanoic acid or stearic acid.