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US 4,012,270 AGranted
Method of improving the adhesion of propylene polymers to enamel coated metal surfaces
AssigneeThe Continental Group, Inc.
InventorChester W. Fitko
Life of this patent
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Abstract
Propylene polymers are heat sealed to enamel coated metal surfaces, the enamel having incorporated therein an adhesion promoting carboxyl modified polypropylene resin. The bond strength of the heat seal is improved by incorporating the carboxyl modified polypropylene resin in the enamel coating formulation dissolved in a hot (heated above 100.degree. C) organic solvent solution selected from aliphatic acids, alcohols and hydrocarbons having at least 10 carbon atoms.
Claims15
A method of heat sealing a propylene polymer to a metal surface which comprises;
- a. preparing a solution of a carboxyl modified polypropylene resin by dissolving an adhesion promoting amount of the resin in a solvent heated to a temperature greater than 100.degree. C, the solvent being selected from the group consisting of saturated and olefinic unsaturated aliphatic acids and alcohols having 10 to 22 carbon atoms and saturated and unsaturated hydrocarbons having 10 to 30 carbon atoms,
- b. adding the resin solution to an enamel coating formulation so that the modified enamel coating formulation is comprised of a solids mixture of about 60 to about 95% by weight of an epoxy resin about 5 to about 40% by weight of a urea formaldehyde resin and about 0.01 to about 5% by weight of the carboxyl modified polypropylene resin,
- c. applying the modified coating formulation to the metal surface,
- d. baking the modified coating formulation to cure and harden the coating,
- e. heat sealing a propylene polymer layer to the hardened enamel coated metal surface and then,
- f. cooling the heat sealed assembly to ambient temperature.
3 more elements
Dependencies are inferred from the claim text.