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US 5,328,724 AGranted
Solution coating process for packaging film
AssigneeE. I. Du Pont de Nemours and Company
InventorGedeon I. Deak
Life of this patent
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Abstract
A process for applying a barrier layer of ethylene/vinyl alcohol copolymer (EVOH) to a substrate, such as a plastic film, by coating the substrate with a solution of EVOH in a solvent of tetrahydrofuran and water, followed by removing the solvent. Multilayer structures having an EVOH barrier layer coated on a plastic substrate from solution in aqueous tetrahydrofuran solvent have excellent oxygen barrier properties.
Claims5
A process for solution coating a substrate with an ethylene/vinyl alcohol copolymer (EVOH) barrier, comprising the steps of:
- (1) agitating a coating solution consisting essentially of
- (A) about 7 to about 20 wt % ethylene/vinyl alcohol copolymer having copolymerized ethylene content from about 20 to about 55 mole %;
- and
- (B) a complementary amount to total to 100 wt % of a solvent consisting essentially of about 10 to about 70 wt % water;
- and a complementary amount to total 100 wt % of tetrahydrofuran;
- at a temperature within the range of about 55.degree.-100.degree. C. until a clear solution is obtained;
- (2) coating at least one surface of the substrate with the coating solution;
- and
- (3) removing the solvent, whereby a dry ethylene/vinyl alcohol copolymer coating on the at least one surface is produced.
6 more elements
Dependencies are inferred from the claim text.