# US 12,765,714 B2 · Crisp plate for microwave ovens

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- Number: US 12,765,714 B2
- Document ID: US12765714B2
- Status: Granted
- Kind: B2
- Application number: 17/941,707
- Filed: 2022-09-09
- Published: 2023-03-16
- Granted: 2026-10-20
- Earliest claimed: 2021-09-14
- Assignees: Whirlpool Corporation
- Applicants: Whirlpool Corporation
- Inventors: Muhammad Khizar
- Web page: https://patentgrep.com/patent/US12765714B2

## CPC

- A47J 36/027: {Cooking- or baking-vessels specially adapted for use in microwave ovens; Accessories therefor}
- A47J 37/0629: {with electric heating elements}
- H05B 6/6408: {Supports or covers specially adapted for use in microwave heating apparatus}
- H05B 6/6494: {for cooking}
- A47J: KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL

## Abstract

A plate for a microwave oven includes a substrate layer for supporting food items to be heated in the microwave oven, with the substrate layer having a first surface. The plate also includes a coating layer on the first surface. The coating layer includes at least one of a ferritic material and a boron nitride compound. The coating layer is configured to be heated by electromagnetic radiation irradiated by the microwave oven.

## Claims

### Claim 1

A plate for a microwave oven, comprising:
a substrate layer for supporting food items to be heated in the microwave oven, the substrate layer having a first surface; and
a coating layer on the first surface, the coating layer including a first layer including a boron nitride compound, and a second layer contacting the first surface and including a ferritic material of at least one of a manganese-zinc ferritic compound, a nickel-manganese ferritic compound, and a nickel-copper-zinc ferritic compound, the second layer being embedded between the first surface and the first layer,
wherein the coating layer is configured to be heated by electromagnetic radiation irradiated by the microwave oven.

### Claim 2 (depends on 1)

The plate of claim 1, wherein the substrate layer has a first thickness, and the coating layer has a second thickness, and the first thickness is greater than the second thickness.

### Claim 3 (depends on 1)

The plate of claim 1, wherein the first surface is a substantially planar contacting surface.

### Claim 4 (depends on 1)

The plate of claim 1, wherein the second layer contacts the first surface and between the substrate layer and the first layer.

### Claim 5 (depends on 4)

The plate of claim 4, wherein the second layer includes the ferritic material dispersed in a polymer matrix.

### Claim 6 (depends on 5)

The plate of claim 5, wherein the polymer matrix is silicone.

### Claim 7 (depends on 1)

The plate of claim 1, wherein the substrate layer includes a second surface opposite to first surface, the second surface being a upper surface in contact with the food items.

### Claim 8

A plate for a microwave oven, comprising:
a substrate layer for supporting food items to be heated in the microwave oven, and
a plurality of coating layers at least partially juxtaposed and in contact with the substrate layer, a first coating layer of the plurality of coating layers including a boron nitride compound, and a second coating layer of the plurality of coating layers including at least one of a ferritic material of at least one of a manganese-zinc ferritic compound, a nickel-manganese ferritic compound, and a nickel-copper-zinc ferritic compound, the second coating layer with the ferritic material positioned between the substrate layer and the first coating layer with a substantially planar contact surface therebetween; and
an auxiliary layer of the plurality of coating layers in substantial contact with the substrate layer and positioned between the substrate layer and the second coating layer with the ferritic material, the auxiliary layer also comprising the boron nitride compound,
wherein the second coating layer with the ferritic material is heatable by an electromagnetic radiation irradiated by the microwave oven.

### Claim 9 (depends on 8)

The plate of claim 8, wherein the plurality of coating layers includes a second layer comprising a polymeric matrix being provided with a silicone, and the polymeric matrix comprises a bi-component pre-polymerized polymer.

### Claim 10 (depends on 8)

The plate of claim 8, wherein the plurality of coating layers includes a second composite layer of a carbon material blended with the ferritic material.

### Claim 11 (depends on 10)

The plate of claim 10, wherein the carbon material is carbon nanotubes, and the ferritic material is ferromagnetic nanowires, and the carbon nanotubes are blended with the ferritic material in an amount of 1.0 wt % to 7.0 wt %.

### Claim 12 (depends on 8)

The plate of claim 8, wherein the ferritic material is a nickel-manganese ferritic compound, a nickel-copper-zinc ferritic compound, a manganese-zinc ferritic compound, a carbon ferrite compound, or combinations thereof.

### Claim 13 (depends on 12)

The plate of claim 12, wherein the nickel-manganese ferritic compound is a Ni0.5Mn0.5F2O4 compound, the nickel-copper-zinc ferritic compound is a Ni0.60-yCuyZn0.42Fe1.98O0.39 compound, and the manganese-zinc ferritic compound is a (MnxZnyFe2+1-x-y)Fe3+2O4 compound.

### Claim 14 (depends on 8)

The plate of claim 8, wherein the at least one coating layer has a textured surface and comprises a plurality of tiles abutting from the substrate layer or a plurality of venting openings configured to vent any gaseous residue trapped in the at least one coating layer and/or in the substrate layer.

### Claim 15 (depends on 8)

The plate of claim 8, wherein the at least one coating layer is configured to reach a surface temperature of at least 200° C. when heated by the microwave oven irradiating an electromagnetic radiation at a power of at least 750 W.

### Claim 16

An assembly comprising:
a microwave oven comprising a microwave source, a cavity, and a wave guide, the microwave source being configured for generating radiation, the cavity being configured for accommodating food items to be heated or cooked or thawed, and the wave guide transferring the electromagnetic radiation from the microwave source to the cavity; and
a plate configured to be placed in the cavity of the microwave oven, the plate including a substrate layer having a top surface for supporting food items to be heated in the microwave oven, and a lower surface opposite to the top surface, and at least one coating layer at least partially juxtaposed and in contact with the substrate layer on the lower surface, the at least one coating layer includes at least a first layer including a boron nitride compound and a second layer including a ferritic material of at least one of a manganese-zinc ferritic compound, a nickel-manganese ferritic compound, and a nickel-copper-zinc ferritic compound, the second layer being positioned between the substrate layer and the first layer,
wherein the at least one coating layer is heatable by the electromagnetic radiation irradiated by the microwave oven.