Pressure formed paperboard tray with oriented polyester film interior
AssigneeInternational Paper Company
InventorsJames R. Quick, James W. Mitchell
Life of this patent
Estimating the term…
Abstract
An ovenable food tray for cooking foodstuffs, such as frozen foodstuffs, in an oven of either the microwave or conventional type. The tray is formed from a flat, unitary laminate blank by deforming the blank in any conventional male and female die apparatus under pressure and heat. The laminate includes a food contacting PET bi-axially oriented film coating adhered to a paperboard base stock by means of a crosslinkable adhesive. The use of such a coating and such an adhesive formulation permits use of the tray in oven temperatures to about 400 degrees F. without delamination of the coating from the paperboard or cracking of the coating.
Claims18
An ovenable food tray comprising a food contacting inner layer of a biaxially-oriented polyethylene terephthalate and an outer layer of paperboard, said layers secured together by and sandwiching a layer of cross-linkable adhesive including a crosslinking agent, whereby the tray exhibits improved resistance to delamination and cracking upon exposure to oven temperatures to about 400 degrees Fahrenheit.
A method of making a paperboard laminate tray including the steps of (1) forming a flat laminate by laminating together a biaxially oriented polyethylene terephthalate resin film and a paperboard base stock by means of a crosslinkable adhesive including a crosslinking agent, and (2) deforming the flat laminate into the shape of a tray.
A method of making a flat unitary laminate blank capable of being formed into an ovenable food tray resistant to delamination and cracking upon exposure to oven temperatures to about 400 degrees Fahrenheit, which comprises,
- a. providing a paperboard stock and a film of biaxially-oriented polyester;
- b. applying a cross-linkable adhesive including a crosslinking agent to a surface of the paperboard stock or of the biaxially-oriented polyester;
- c. contacting the adhesive coated surface of the paperboard stock with a surface of the biaxially-oriented polyester or contacting the adhesive coated surface of the biaxially-oriented polyester with a surface of the paperboard stock;
- and
- d. heating the thus formed laminate at about 400 degrees Fahrenheit.
A flat unitary laminate blank capable of being formed into an ovenable food tray resistant to delamination and cracking upon exposure to oven temperatures to 400 degrees F, which consists of a layer of paperboard stock and a layer of biaxially-oriented polyester adhered to each other by means of a cross-linkable adhesive including a crosslinking agent.
A method of making an ovenable food tray formed from a paperboard stock and a film of biaxially-oriented polyester, said food tray being resistant to delamination and cracking upon exposure to oven temperatures up to 400 degrees Fahrenheit, which comprises,
- a. applying a cross-linkable adhesive including a crosslinking agent to a surface of the paperboard stock or of the biaxially-oriented polyester;
- b. contacting the adhesive coated surface of the paperboard stock with a surface of the biaxially-oriented polyester, or contacting the adhesive coated surface of the biaxially-oriented polyester with a surface of the paperboard stock , to form a flat laminate;
- c. heating the thus formed flat laminate at about 400 degrees Fahrenheit;
- and
- d. deforming the flat laminate into the shape of a food tray.
Dependencies are inferred from the claim text.