Patterned microwave susceptor

• US 6,414,290 B1
• Filed: 03/19/1998
• Issued: 07/02/2002
• Est. Priority Date: 03/19/1998
• Status: Expired due to Term

• Current Assignee: Graphic Packaging International Incorporated
• Original Assignee: Graphic Packaging Corporation
• Inventors: Lafferty, Terrence P., Cole, Lorin R.
• Primary Examiner(s): Hoang, Tu Ba
• Application Number:
  US09/044,576
• Time in Patent Office: 1,566 Days
• Field of Search: 219/730-735, 219/728, 219/759, 426/107, 426/109, 426/234, 426/241, 426/243, 99D/IG.14
• US Class Current: 219/759
• CPC Class Codes: B65D 2581/3406 Pizza or bread
• CPC Class Codes: B65D 2581/344 Geometry or shape factors influencing the microwave heating properties
• CPC Class Codes: B65D 2581/3467 Microwave reactive layer shaped by delamination, demetallizing or embossing
• CPC Class Codes: B65D 2581/3472 Aluminium or compounds thereof
• CPC Class Codes: B65D 2581/3494 Microwave susceptor B65D2581/3487 takes precedence
• CPC Class Codes: B65D 81/3446 specially adapted to be heated by microwaves
• CPC Class Codes: H05B 6/6494 for cooking

Abstract

The heating effect of a microwave susceptor can be improved by providing a pattern of microwave transparent areas in the susceptor. The transparent areas are preferably circles having a diameter of about 0.5 inch. The distance between adjacent circles is preferably about 0.5 inch. The susceptor may be used to brown and crispen the crust of frozen pizza heated in a microwave oven. The crust of the pizza is browner, especially at its central area, than the crust of pizza heated using a conventional susceptor.

Claims

1. In an imperforate microwave susceptor comprising a layer of metallized plastic film laminated to a dimensionally stable substrate, the improvement wherein the susceptor has a pattern of substantially transparent circles in the layer of metal on the plastic film that enhances the heating effect of the susceptor in the central area of the susceptor, with each circle having a diameter of about 1.3 cm, the distance between adjacent circles being between about one and three cm, and the susceptor being electrically continuous.

2. The improvement of claim 1, wherein the proportion of the cumulative area of the transparent circles in the central area of the susceptor to the total area of the central area of the susceptor is from about 10 to 20%, and the central area of the susceptor having an area of about 80 sq. cm.

3. A microwave susceptor comprising:

a dimensionally stable substrate; and

a generally continuous layer of metallized plastic film laminated to the substrate to form a microwave susceptor, the film having spaced-apart microwave-transparent areas within one generally continuous microwave-interactive area for enhancing the heating effect of the susceptor, each of the transparent areas having a major linear dimension of about one eighth an operating wavelength of a microwave oven.

4. The microwave susceptor of claim 3, wherein each of the transparent areas has a major linear dimension of about 1.3 cm.

5. The microwave susceptor of claim 3, wherein each transparent area has a width to height ratio between about 1 to 1 and about 2 to 1.

6. The microwave susceptor of claim 3, wherein each transparent area has a generally circular shape.

7. The microwave susceptor of claim 3, wherein adjacent transparent areas are separated by between about 1 and 3 cm.

8. The microwave susceptor of claim 3, wherein the susceptor is electrically continuous.

9. The microwave susceptor of claim 3, wherein the dimensionally stable substrate is paper or paperboard.

10. The microwave susceptor of claim 3, wherein the susceptor has a center portion surrounded by an outer portion, and wherein the center portion of the susceptor is at least 10 cm from a nearest edge of the susceptor.

11. The microwave susceptor of claim 10, wherein a cumulative area of the microwave-transparent areas disposed within the center portion is about 10% to 20% of a total area of the center portion.

12. The microwave susceptor of claim 3, wherein a cumulative area of the microwave transparent areas is about 7% to 15% a total area of the susceptor.

13. The microwave susceptor of claim 3, wherein the susceptor includes a peripheral margin portion having a microwave-transparent grid pattern.

14. The microwave susceptor of claim 3, wherein the transparent areas become more concentrated toward a center region of the susceptor.