CA1221338A - Container for use in microwave ovens - Google Patents
Container for use in microwave ovensInfo
- Publication number
- CA1221338A CA1221338A CA000364231A CA364231A CA1221338A CA 1221338 A CA1221338 A CA 1221338A CA 000364231 A CA000364231 A CA 000364231A CA 364231 A CA364231 A CA 364231A CA 1221338 A CA1221338 A CA 1221338A
- Authority
- CA
- Canada
- Prior art keywords
- tray
- microwave energy
- microwave
- absorptive
- liner
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Package Specialized In Special Use (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A disposable tray for use in a microwave oven formed of material that is substantially non-absorptive of microwave energy having thereon a material that is absorptive of microwave energy.
A disposable tray for use in a microwave oven formed of material that is substantially non-absorptive of microwave energy having thereon a material that is absorptive of microwave energy.
Description
~2~33~
BACKGROUND OF THE INVENTION
This invention relates to trays for use in microwave ovens, and especially to disposable trays absorptive of microwave energy.
Frozen foods conveniently are packaged in sealed aluminum or paper board trays in which the foods may be cooked or heated for serving. Such trays are satisfactory for use in conventional ovens Usage of the same trays in microwave ovens, however, has not been encouraged. Aluminum trays are, for example, highly reflective of microwave energy and their usage has not been recomb mended by manufacturers of microwave ovens Paper board trays have not been found to be sufficiently absorptive of microwave energy to be effective. The net result, using either type of tray, has been that foods are often non-uniformly heated to the extent that they may be cold in one region while burned in another region.
Efforts directed to overcoming such difficulties have involved provision of especially designed appliances for enclosing trays of the aforementioned type, or even the reconstruction of the trays in order to absorb and concentrate the microwave energy.
Such efforts, while achieving desired results, are costly.
The following documents are representative of prior art believed material to the examination of this application:
U S. Patent No. 3,547,661 discloses a container provided with a pattern of apertures for selectively heating different foods therein.
~2~33~
U.S. Patent No. 3,997,677 discloses a hermetically sealed package, for use in microwave ovens, formed either of mailmen or of polycar~onate film adhered to polyethylene film by epoxy adhesive.
U.S. Patent No. 3,~81,027 discloses an appliance come prosing an enclosure of mossy material for a frozen food package and adapted for placing in a microwave oven.
U.S. Patent No. 3,615,713 discloses aluminum foil coverer by a cardboard or a plastic wrapper transparent to micro-wave energy.
U.S. Patent Jo. 4,143,647 discloses a porcelain dish including a portion covered with tin oxide, for use in a micro-wave oven.
U.S. Patent No. 3,97~,354 discloses a ceramic dish provided with integral handles having first microwave reflective coatings and second coatings of a material of low heat conduct tivity.
The publication "Quick Frozen Foods", November, 1974, edition, at page 20, second column, discloses "Corning" (a Trademark) heating dishes that employ a thin coating of tin oxide as a heating element.
The present invention provides an improved disposable tray for use in a microwave oven.
The present invention also provides an improved package for both frozen storage of foods and heating of the same foods in a microwave oven.
The present invention still further provides a disposable microwave heat-in tray for packaging frozen foods and capable of being readily formed prom blanks using convent tonal molding techniques.
cDr~i~g Jo the present invention there is provided disposable molded paper board tray for holding and heating food ~22~33~
in a microwave oven, said tray having side and bottom walls of paper board that is substantially fluid previous and non-absorptive of microwave energy and a fluid impervious liner, characterized by a layer of material that is absorptive ox microwave energy adherent to and co-extensive with the side and bottom walls of said paper board tray, said material having the capability of being heated when subjected to microwave energy in said oven, thereby heating food in said tray.
Thus, the present invention provides a disposable tray for use in a microwave oven to heat food, comprising a structure having walls of a material that is substantially non-absorptive of microwave energy, and a material that is absorptive of micro-wave energy disposed on said walls of non-absorptive material.
-pa I
The manner in which the foregoing as well as other objectives and advantages may best be achieved will be more fully understood from a consideration of the following description, taken in light of the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a perspective view of a tray embodying the invention;
Figure 2 is a sectional view taken along the line 2-2 in Figure 1, as seen looking in the direction of arrows applied thereto; and . Figures 3 to 7 are views similar to Figure 2, and illustrating modified embodiments of the invention.
DETAILED DESCRIPTION OF THE SEVERAL EMBODIMENTS
With more detailed reference to the drawing, there is seen in Figure 1 a tray 10 embodying the invention having side and bottom walls 11 and 12, respectively! an upper peripheral flange 13.
In the embodiment shown, and with reference also to Figure 2, tray 10 is molded from a laminate blank (not shown) and comprises:
an inner liner 14 selected from the group consisting of polyester, nylon, and greaseproof paper; an intermediate layer 15 of paper board;
and an outer layer 16 of a microwave absorptive material, for example tin oxide.
In Figure 3, a molded tray 10 is formed from a laminate including: a liner 114 selected also from the group consisting of polyester, nylon and greaseproof paper; an outer layer 115 of paper board; and an intermediate layer 116 of a compound of adhesive and tin oxide.
In Figure 4, a molded tray 210 is formed from a laminate comprising an outer layer 215 of paper board and an inner layer 216 comprising a thermosetting plastic resin selected from the group consisting of melamine-formaldehyde, epoxy, and alkyd.
~2;~33~
1 In Figure 5, a molded tray 310 similar to the tray of Figure 2 L~cl~r~es an Ann pl~s~lc liner 31~ selected from top group consisting of polyester, nylon, and grease-proof popper; an intermediate layer 315 of paperboarcl; and an outer fever 31~ of a microwave absorptive material, for example tin owe, ought on the tray side and bottom walls 311 and 312, respectively, jut not on flange 313. Absence of the tin oxide from flange 313 affords an essentially unheated tray proton that facilitates handling my the user.
In Figure 6, a tray 410 is formed from an inner layer 417 of aluminum foil and an outer layer 416 of tin oxide as the microwave absorptive material.
In Figure 7 a tray 510 is formed from an inner fever 517 of aluminum foil and an outer layer 518 of a microwave absorptive material selected from the group consisting of melamine~formaldehyde, epoxy, and alkyd.
In Figure 8, a tray 610 is formed from paper board lo that has been saturated with a thermosetting plastic selected from the group consisting of melamine-formaldehyde, epoxy, and aloud.
While tin oxide is preferred, it is to ye understood that other metal oxides are contemplated by the invention. For example ferris . oxide has been found useful.
From the foregoing it will be appreciated that the invention affords inexpensive, disposable heat-in trays for use in microwave ovens, which trays are readily ~orme~J using convention]. tray molding techniques an apparatus. moreover the varlo~ls absorptive materials mazy be applied by coating or printing, and, in the case of the purebred trays, by saturating the ask with assertive material to permeate the same. These same absorptive materials ma 30 also be applied in selective patterns to provide heating only in certain regions of the tray.
Lo 1 Particularly as respects the aluminum trays, provision of a microwave energy absorbent material thereon ensures awns-reflection of microwave energy back to the magnetron of an oven, thereby extending life of this costly component of the oxen Rapid, even heating is achieved, since heat is applied to contents of the tray from the bottom as well as the top. Moreover, aluminum trays thus coated are rendered "two way", being usable in both in ray red and microwave ovens.
Comparative tests were made between conventional aluminum foil lo trays and the same aluminum foil trays coated with melamine-formaldehvde, in ~emonstrat on of advantages achieved TV
the invention. More particularly, a 5 l/2 inch long, 3 3/8 inch wide, 2 inch deep E-Z Fowl (Trademark) aluminum tray was coated with grooms ox melamîne-formaldehyde and cured at 350F for 25 minutes. The tray was filled with lo ml. of water, and the temperature of the tray and water lowered to 2~F for a sufficient period of time to freeze the water. An uncoated aluminum foil tray of the same size was filled with the same amount of water arc frozen in the same manner as the coated tea. Each tray was subjected to 700 watts of microwave energy for 300 seconds. The temperature of water in the coated tray rose to 124F, whereas toe temperature of water in the uncoated tray rose to only 68F. This significant increase in temperature was the result of microwave energy being absorbed by the melamine~fo milkweed coating and toe generated heat being transferred', to the aluminum tray and its contents.
In another test, a paper board tray 6 inches long, 5 inches Waco, and 7/8 inch deep was coated with a fever of neiamine-formalc'ehvcle The coated tray assay filled with 200ml. of water, which was then frozen and its temperature towered to 24F. The tray and its contents were then s~lbjectecl to 1400 watts of microwave energy for a period of loo seconds, at toe old of which the resulting water temperature was 90 F. on uncoated paper tray was tested in the same manner, tune temperature rising to only 75F.
~Z:~3~
1 In an event it should be appreciated that frozen foods, as well as leer do not Assyria mlcrowa~e energy energy well until their are thawed and become capable of being polarized and subjected to the rapid alternations of microwave? energy. Advantageously, a treated tray embodying the present invention hastens the thawing process.
BACKGROUND OF THE INVENTION
This invention relates to trays for use in microwave ovens, and especially to disposable trays absorptive of microwave energy.
Frozen foods conveniently are packaged in sealed aluminum or paper board trays in which the foods may be cooked or heated for serving. Such trays are satisfactory for use in conventional ovens Usage of the same trays in microwave ovens, however, has not been encouraged. Aluminum trays are, for example, highly reflective of microwave energy and their usage has not been recomb mended by manufacturers of microwave ovens Paper board trays have not been found to be sufficiently absorptive of microwave energy to be effective. The net result, using either type of tray, has been that foods are often non-uniformly heated to the extent that they may be cold in one region while burned in another region.
Efforts directed to overcoming such difficulties have involved provision of especially designed appliances for enclosing trays of the aforementioned type, or even the reconstruction of the trays in order to absorb and concentrate the microwave energy.
Such efforts, while achieving desired results, are costly.
The following documents are representative of prior art believed material to the examination of this application:
U S. Patent No. 3,547,661 discloses a container provided with a pattern of apertures for selectively heating different foods therein.
~2~33~
U.S. Patent No. 3,997,677 discloses a hermetically sealed package, for use in microwave ovens, formed either of mailmen or of polycar~onate film adhered to polyethylene film by epoxy adhesive.
U.S. Patent No. 3,~81,027 discloses an appliance come prosing an enclosure of mossy material for a frozen food package and adapted for placing in a microwave oven.
U.S. Patent No. 3,615,713 discloses aluminum foil coverer by a cardboard or a plastic wrapper transparent to micro-wave energy.
U.S. Patent Jo. 4,143,647 discloses a porcelain dish including a portion covered with tin oxide, for use in a micro-wave oven.
U.S. Patent No. 3,97~,354 discloses a ceramic dish provided with integral handles having first microwave reflective coatings and second coatings of a material of low heat conduct tivity.
The publication "Quick Frozen Foods", November, 1974, edition, at page 20, second column, discloses "Corning" (a Trademark) heating dishes that employ a thin coating of tin oxide as a heating element.
The present invention provides an improved disposable tray for use in a microwave oven.
The present invention also provides an improved package for both frozen storage of foods and heating of the same foods in a microwave oven.
The present invention still further provides a disposable microwave heat-in tray for packaging frozen foods and capable of being readily formed prom blanks using convent tonal molding techniques.
cDr~i~g Jo the present invention there is provided disposable molded paper board tray for holding and heating food ~22~33~
in a microwave oven, said tray having side and bottom walls of paper board that is substantially fluid previous and non-absorptive of microwave energy and a fluid impervious liner, characterized by a layer of material that is absorptive ox microwave energy adherent to and co-extensive with the side and bottom walls of said paper board tray, said material having the capability of being heated when subjected to microwave energy in said oven, thereby heating food in said tray.
Thus, the present invention provides a disposable tray for use in a microwave oven to heat food, comprising a structure having walls of a material that is substantially non-absorptive of microwave energy, and a material that is absorptive of micro-wave energy disposed on said walls of non-absorptive material.
-pa I
The manner in which the foregoing as well as other objectives and advantages may best be achieved will be more fully understood from a consideration of the following description, taken in light of the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a perspective view of a tray embodying the invention;
Figure 2 is a sectional view taken along the line 2-2 in Figure 1, as seen looking in the direction of arrows applied thereto; and . Figures 3 to 7 are views similar to Figure 2, and illustrating modified embodiments of the invention.
DETAILED DESCRIPTION OF THE SEVERAL EMBODIMENTS
With more detailed reference to the drawing, there is seen in Figure 1 a tray 10 embodying the invention having side and bottom walls 11 and 12, respectively! an upper peripheral flange 13.
In the embodiment shown, and with reference also to Figure 2, tray 10 is molded from a laminate blank (not shown) and comprises:
an inner liner 14 selected from the group consisting of polyester, nylon, and greaseproof paper; an intermediate layer 15 of paper board;
and an outer layer 16 of a microwave absorptive material, for example tin oxide.
In Figure 3, a molded tray 10 is formed from a laminate including: a liner 114 selected also from the group consisting of polyester, nylon and greaseproof paper; an outer layer 115 of paper board; and an intermediate layer 116 of a compound of adhesive and tin oxide.
In Figure 4, a molded tray 210 is formed from a laminate comprising an outer layer 215 of paper board and an inner layer 216 comprising a thermosetting plastic resin selected from the group consisting of melamine-formaldehyde, epoxy, and alkyd.
~2;~33~
1 In Figure 5, a molded tray 310 similar to the tray of Figure 2 L~cl~r~es an Ann pl~s~lc liner 31~ selected from top group consisting of polyester, nylon, and grease-proof popper; an intermediate layer 315 of paperboarcl; and an outer fever 31~ of a microwave absorptive material, for example tin owe, ought on the tray side and bottom walls 311 and 312, respectively, jut not on flange 313. Absence of the tin oxide from flange 313 affords an essentially unheated tray proton that facilitates handling my the user.
In Figure 6, a tray 410 is formed from an inner layer 417 of aluminum foil and an outer layer 416 of tin oxide as the microwave absorptive material.
In Figure 7 a tray 510 is formed from an inner fever 517 of aluminum foil and an outer layer 518 of a microwave absorptive material selected from the group consisting of melamine~formaldehyde, epoxy, and alkyd.
In Figure 8, a tray 610 is formed from paper board lo that has been saturated with a thermosetting plastic selected from the group consisting of melamine-formaldehyde, epoxy, and aloud.
While tin oxide is preferred, it is to ye understood that other metal oxides are contemplated by the invention. For example ferris . oxide has been found useful.
From the foregoing it will be appreciated that the invention affords inexpensive, disposable heat-in trays for use in microwave ovens, which trays are readily ~orme~J using convention]. tray molding techniques an apparatus. moreover the varlo~ls absorptive materials mazy be applied by coating or printing, and, in the case of the purebred trays, by saturating the ask with assertive material to permeate the same. These same absorptive materials ma 30 also be applied in selective patterns to provide heating only in certain regions of the tray.
Lo 1 Particularly as respects the aluminum trays, provision of a microwave energy absorbent material thereon ensures awns-reflection of microwave energy back to the magnetron of an oven, thereby extending life of this costly component of the oxen Rapid, even heating is achieved, since heat is applied to contents of the tray from the bottom as well as the top. Moreover, aluminum trays thus coated are rendered "two way", being usable in both in ray red and microwave ovens.
Comparative tests were made between conventional aluminum foil lo trays and the same aluminum foil trays coated with melamine-formaldehvde, in ~emonstrat on of advantages achieved TV
the invention. More particularly, a 5 l/2 inch long, 3 3/8 inch wide, 2 inch deep E-Z Fowl (Trademark) aluminum tray was coated with grooms ox melamîne-formaldehyde and cured at 350F for 25 minutes. The tray was filled with lo ml. of water, and the temperature of the tray and water lowered to 2~F for a sufficient period of time to freeze the water. An uncoated aluminum foil tray of the same size was filled with the same amount of water arc frozen in the same manner as the coated tea. Each tray was subjected to 700 watts of microwave energy for 300 seconds. The temperature of water in the coated tray rose to 124F, whereas toe temperature of water in the uncoated tray rose to only 68F. This significant increase in temperature was the result of microwave energy being absorbed by the melamine~fo milkweed coating and toe generated heat being transferred', to the aluminum tray and its contents.
In another test, a paper board tray 6 inches long, 5 inches Waco, and 7/8 inch deep was coated with a fever of neiamine-formalc'ehvcle The coated tray assay filled with 200ml. of water, which was then frozen and its temperature towered to 24F. The tray and its contents were then s~lbjectecl to 1400 watts of microwave energy for a period of loo seconds, at toe old of which the resulting water temperature was 90 F. on uncoated paper tray was tested in the same manner, tune temperature rising to only 75F.
~Z:~3~
1 In an event it should be appreciated that frozen foods, as well as leer do not Assyria mlcrowa~e energy energy well until their are thawed and become capable of being polarized and subjected to the rapid alternations of microwave? energy. Advantageously, a treated tray embodying the present invention hastens the thawing process.
Claims (6)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A disposable molded paperboard tray for holding and heating food in a microwave oven, said tray having side and bottom walls of paperboard that is substantially fluid pervious and non-absorptive of microwave energy and a fluid impervious liner, characterized by a layer of material that is absorptive of microwave energy adherent to and coextensive with the side and bottom walls of said paperboard tray, said material having the capability of being heated when subjected to microwave energy in said oven, thereby heating food in said tray.
2. The tray of Claim 1, wherein microwave absorptive material comprises a metal oxide selected from the group consisting of iron oxide and tin oxide.
3. The tray of Claim 1, wherein said fluid impervious liner comprises a thermosetting plastic resin selected from the group consisting of epoxy and alkyd resins which also comprises the microwave energy absorbent material.
4. The tray of Claim 2, wherein said liner is selected from the group consisting of polyester, nylon, and grease-proof paper and said microwave energy absorbent materi-al is a compound of adhesive and said metal oxide adhering said liner to said side and bottom walls.
5. The tray of Claim 1, wherein said layer of microwave energy absorptive material is disposed on the ex-ternal surfaces of said tray.
6. A tray according to any of Claims 1, 2, or 5 wherein said tray is provided with a flanged rim devoid of said layer of microwave energy absorptive material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000364231A CA1221338A (en) | 1980-11-07 | 1980-11-07 | Container for use in microwave ovens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000364231A CA1221338A (en) | 1980-11-07 | 1980-11-07 | Container for use in microwave ovens |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1221338A true CA1221338A (en) | 1987-05-05 |
Family
ID=4118381
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000364231A Expired CA1221338A (en) | 1980-11-07 | 1980-11-07 | Container for use in microwave ovens |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1221338A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5070223A (en) * | 1989-03-01 | 1991-12-03 | Colasante David A | Microwave reheatable clothing and toys |
-
1980
- 1980-11-07 CA CA000364231A patent/CA1221338A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5070223A (en) * | 1989-03-01 | 1991-12-03 | Colasante David A | Microwave reheatable clothing and toys |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3547661A (en) | Container and food heating method | |
| AU616996B2 (en) | Control of microwave interactive heating by patterned deactivation | |
| US4230924A (en) | Method and material for prepackaging food to achieve microwave browning | |
| JPH0212831B2 (en) | ||
| US5593610A (en) | Container for active microwave heating | |
| US4190757A (en) | Microwave heating package and method | |
| CA2054671C (en) | Method and apparatus for use in microwave heating | |
| US4948932A (en) | Apertured microwave reactive package | |
| CA1091305A (en) | Microwave heating package and method | |
| CA2588756A1 (en) | Microwaveable container for food products using a microwave shielding to optimize heating | |
| EP0867103B1 (en) | Microwave cooking container for food items | |
| US5126518A (en) | Microwave cooking container cover | |
| US4210124A (en) | Dish for holding food to be heated in a microwave cooking chamber | |
| US4143647A (en) | Dish for holding food to be heated in a microwave cooking chamber | |
| EP0161739A2 (en) | Microwave heating package | |
| CA1221338A (en) | Container for use in microwave ovens | |
| EP0350660A3 (en) | Composite sheet stock for microwave heating and receptacle | |
| GB2202118A (en) | Packaging materials for use in microwave ovens | |
| US20040169037A1 (en) | Water vapour generating device for heating foodstuffs in a microware oven | |
| WO1987002334A1 (en) | Microwave interactive package containing stainless steel and method of making same | |
| JP2721876B2 (en) | Microwave cooking containers | |
| JPS638633Y2 (en) | ||
| JPS62252831A (en) | Food heating control method for high frequency heating apparatus and food package material used for said method | |
| JP2006076657A (en) | Food packed in container for heating by microwave oven, and container | |
| JPH1085130A (en) | Cooking vessel for microwave oven |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |