CA2211071C - Multilayer fused microwave conductive structure - Google Patents

Multilayer fused microwave conductive structure Download PDF

Info

Publication number
CA2211071C
CA2211071C CA002211071A CA2211071A CA2211071C CA 2211071 C CA2211071 C CA 2211071C CA 002211071 A CA002211071 A CA 002211071A CA 2211071 A CA2211071 A CA 2211071A CA 2211071 C CA2211071 C CA 2211071C
Authority
CA
Canada
Prior art keywords
fuse
conductive
microwave
susceptor
food
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 - Fee Related
Application number
CA002211071A
Other languages
French (fr)
Other versions
CA2211071A1 (en
Inventor
Glenn J. Walters
John A. Mccormick
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Graphic Packaging Corp
Original Assignee
Graphic Packaging Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Graphic Packaging Corp filed Critical Graphic Packaging Corp
Publication of CA2211071A1 publication Critical patent/CA2211071A1/en
Application granted granted Critical
Publication of CA2211071C publication Critical patent/CA2211071C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D81/00Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D81/34Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within the package
    • B65D81/3446Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within the package specially adapted to be heated by microwaves
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2581/00Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D2581/34Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within
    • B65D2581/3437Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within specially adapted to be heated by microwaves
    • B65D2581/3439Means for affecting the heating or cooking properties
    • B65D2581/344Geometry or shape factors influencing the microwave heating properties
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2581/00Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D2581/34Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within
    • B65D2581/3437Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within specially adapted to be heated by microwaves
    • B65D2581/3439Means for affecting the heating or cooking properties
    • B65D2581/3447Heat attenuators, blocking agents or heat insulators for temperature control
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2581/00Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D2581/34Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within
    • B65D2581/3437Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within specially adapted to be heated by microwaves
    • B65D2581/3463Means for applying microwave reactive material to the package
    • B65D2581/3466Microwave reactive material applied by vacuum, sputter or vapor deposition
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2581/00Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D2581/34Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within
    • B65D2581/3437Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within specially adapted to be heated by microwaves
    • B65D2581/3471Microwave reactive substances present in the packaging material
    • B65D2581/3472Aluminium or compounds thereof
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2581/00Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D2581/34Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within
    • B65D2581/3437Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within specially adapted to be heated by microwaves
    • B65D2581/3471Microwave reactive substances present in the packaging material
    • B65D2581/3474Titanium or compounds thereof
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2581/00Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D2581/34Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within
    • B65D2581/3437Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within specially adapted to be heated by microwaves
    • B65D2581/3471Microwave reactive substances present in the packaging material
    • B65D2581/3477Iron or compounds thereof
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2581/00Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D2581/34Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within
    • B65D2581/3437Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within specially adapted to be heated by microwaves
    • B65D2581/3471Microwave reactive substances present in the packaging material
    • B65D2581/3477Iron or compounds thereof
    • B65D2581/3478Stainless steel
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2581/00Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D2581/34Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within
    • B65D2581/3437Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within specially adapted to be heated by microwaves
    • B65D2581/3471Microwave reactive substances present in the packaging material
    • B65D2581/3479Other metallic compounds, e.g. silver, gold, copper, nickel
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2581/00Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D2581/34Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within
    • B65D2581/3437Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within specially adapted to be heated by microwaves
    • B65D2581/3486Dielectric characteristics of microwave reactive packaging
    • B65D2581/3494Microwave susceptor
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S99/00Foods and beverages: apparatus
    • Y10S99/14Induction heating

Abstract

A conductive structure for use in microwave food packaging which adapts itself to heat food articles in a safer, more uniform manner is disclosed. The structure includes a conductive layer disposed on a non-conductive substrate. Provision in the structure's conductive layer of fusel inks and base areas causes microwave induced currents to be channeled through the fuse links, resulting in a controlled heating. When over-exposed to microwave energy, fuses break more readily than the conductive base areas resulting in less absorption of microwave energy in the area of fuse breaks than in other regions where fuses do not break. The arrangement and dimensions of fuse links compensate for known uneven stresses in the substrate, giving uniform fuse performance. In addition, by varying the dimensions of the fuse links and base areas it is possible to design and fabricate different fused microwave conductive structures having a wide range of heating characteristics.
Thus, a fused microwave conductive structure permits food heating temperatures to be tuned for food type.

Description

MiTLTILAYER li'IJS>JY} MiCROWAVE C4tVi}ICTI'VF STRUC'TU1ZF
F'eIi d ofThe Invention The present invention relates generally to the field of microwave conductive strucuzres for improving the cooking, heating or browning of food in microwave ovens. More particularly, the invention relates to articles usable in conventional food packaging which interact with electromagnetic energy generated by the microwave oven and adapt to different microwave oven types, food compositions and food geometries.

BaCk.groUnd An example of a microwave conductive structure is a microwave susc:,ptor which is an article which absorbs microwave energy, eanverts it into heat and conducts the heat generated into food articles placed in close proximity thereto. Microwave susceptors are particularly useful in microwave food packaging to aid in browning or crisping those foods which are preferably prepared by a method which browns or crisps the food.
The field of microwave conductive packaging technology inciudes numerous attempts to optimize heating, browning and crisping of food cooked in microwave ovens.
Such attempts include the selectively miczowave-permeable membrane susceptor shown in prior U.S. patent number 5,185,506, issued February 9, 1993 and U.S. patent number 5,245,821 issued October 19, 1993. Other attempts include a microwaveable barrier film described in L'.S.-patent number 5,256,846 issued October 26, 1993 and a microwave diffu.ser film described in U.S. patent number 5,300,746 issued Apri15, 1994. U.S. patents 5,185,506 and 5,245,821 disclose examples of constructions whicli modify the overall heating pattern in a;nicrowave oven in an attempt to optimize the heating for a specific food product and geometry. However, these and conventional :
microwa.ve susceptor structures do not adequately address the heating problems associated with non-unii'orm electromagnetic fields found in all microwave ovens.
The unpredictability of the microwave field within a mierowave oven is a significant problem foz articles and methods which attempt to make heating, browning or crisping of food uniform. There are morc than 500 models of microwave ovens on the market today, all of which AMENDED SHEET
have different heating patterns and r,on-unifbrm energy fields. Since most food products themselves are non-uniform in size and shape, there is an increased natural tendency of food to heat unevenly. The inability to adequately predict locations of hot spots and cold spots within a microwaved, packaged food item including a susceptpr has made this area the subject of much research. For example, fishsticks or french fries loosely packaged in a box containing a six-inch by six-inch susceptor on the bottom, are often not properly crisped during cooking. Food items shield the susceptor from microwave energy, absorbing energy during microwave heating of the food. After exposure to the microwave field in a microwave oven, there will thus be noticeable differences in the heat jenerated by the 36-inch square susceptor, depending on the location of c o the food product. For instance, wherevar the food product does not cover the susceptor material, the susceptor will get extremely hot, often hot enoug.h to cause damage to the package. Indeed, it has been reported that susceptor packages have caught fire in consumer microwave ovens. In stlmmary, susceptor areas not covered by the food product get extremely hot.
At the edges of the food product, the susceptor will also reach extremely high temperatures.
However, the susceptor i i material near the center of the food product will reaeh a much lower temperature. The net result is that the heat gain of the susceptor is not balanced over the susceptor area.
Moreover, as discussed in U.S. patent ntunber 5,041,295, issued August 20, 1991, moisture can become trapped between a food item and an impermeable susceptor, causing inadequate crisping of the food item. The susceptor disclosed therein develop cracks which 20 permit escape of trapped moisture, leaving the heated food surface sufficiently dry to be perceived as crisp_ The cracks also cause the susceptor disclosed to "turn off' after having performed its heating function.
A. need exists for a microwave conductive structure which exhibits enhanced safety and performance over existing commercial microwave susceptors, and also for a micrawave 25 conductive structure which adapts itself in a controlled manner on the basis of the oven, food geometry, food location and food composition, so as to provide more uniforrn heating, browning and crisping of food products.
Summary 4f The Inyention The above general goals and such other goals as will be obvious to those skilled in the art 30 are met in the present invention, wherein there is provided a fused microwave conductive structure.A fused microwave conductive structure for use in food packaging may comprise a substrate layer and an electrically conductive layer deposited on a surface of the substrate layer.

AMFNnFn cucnr The conductive Ia.fer ras fuse Iir_ks with corulect adjacent conductive base areas. Base areas serve as conductive paths between fuse links, and act in connection with the fuse links to ;cnerate heat on exposure to m.icrowave eneray. Base areas are less susceptible to breaking upon exposure to microwave energy than the fuse li.nlcs, which are substantially susceptible to such S

7..~5_ .. a ~''%.?" :F.f''~.. :='<:
.:3.i: .. ..r..,.,..M.,. ~.~ A. ,w'~'v . ...~ of . ~...~.?='.'~., "~33~..,<
t'~ ... -".~.`..,.' .;.~ of ~':? i'3. tw,.~. ~-,`-= 1.i.~:.

:i':1:.:... .y~..Y _. ~7c:M areas . .. . ..' i. "=~;:'. p.~`i~::
~.'..f:; y. 1:a .:z..:... e~v r .".b,.,, ,, in accordance zR`.i.::t3.
"::3.r...Ci.-:f,;.t .;,."'pH^"t:7 w`... the Y11."f':s:'=~en,? invention, f':.='&:' link , ha::)eh, 7:.. ..2E;E, and ........r`.'=.;.t;:?t...o;".`.t:i b%?...::.i%,..-.:t? :>2..2s er.tiw;'.7..,.,:?..ty of fu:ae link ?~3"ei.'+.?C;.:gr-: to eI-.",3C, sur,a to c..= yr { : :.i,. ~t. .~. '. wa3+ +?
f.~ :'er:.%. over ::.~;.f' :~ .'::; N...;.:~"(3.
..; ~J

--- pG1i'...'t,..::......:.i: according to on'<: xs'M"'e..L of the p.`.:es..nt 3...i%t::'L;.'C:3..i:Eiy the2:r..+~'. is provided a fused s1.3.s.'..'ept:=:yr st...:C:i,..ui.w: ...I)..,...udinC a _iC%.._. -r:Li duc .:.vr"'+'-^..' s't.l.::`;::tr=3 v'>;' , .i..3... i anwi. :3.
conductive la4`f?''}: (103) d."..?pt',...,;:t on t;.::.'c.a. .::i:"7:I'3.
.::..:.t1duf"`".., vf:

." ub;-:. ., .i:'=3 ".. :. (101).: t' :tra:., ":. er... .': eC.,'~. b'r' , the ; <, ; .: t;,' , %>= = ... , ye; ' t .. :'.. , d::" , . d;:id into a plurality of fuse l'i,;:.kc:.: 109;
;..3').r:< :i%;:L".c;

ar::a a.. (107) by ?` gi:, r:.:.. (105) of :? '. i.;..: stantial Y' .l. e; ; s cia-:C'~u,... .. .+.... J tlii::n t1'3.e conductive ...:zv4:.::' .1031 a wh.f::re:1.".. .:h<u`
,..usc; _, 3'3.%ir? (109) Mi's e ....: 3 :3. :3.geC:; _3"? _,. lc'"%:3.s't..
;r,J w33 :.e:' : ............i:?: M: f an+.. the fuse 5. ..n..S.s (109) of b.l...h .i....ieni.....nions are equally .= F.;.::i c.: pt.....:,) le to % brf.''.' i..., ..:t. a ~~ upon F': xpLi i v.re to :':'3 :. +.: i.'o'A3 G:1";'tv'. :: n rt:iy,.
According to another aspect of the present `~ s there ,1.~;J. \ ~ .:.:Z,:..A{~::a..:t.i fused s~1:. ..z:~~: c;r~ t'Ja.
~.< c:+t2"?... r:....~
t`.,? a ~.w%..~t.l,..
r._:.t'L.:;~.:1..

...nid.iud.,,nw a ..i.o._ "i..4:rd:.:cLiYve substrate ~ ~ and .b a c'.J: :[' w\:y`.,`., .}
L..}.. vrC'~~' layer (103) disposed on the ,...`::n'coinl_uci ivre tiiu.t...~:7..~,~r,.ate (... . ).
i ....'Ci.,.r~'..~L i. 1 _ .a t~.-..rõ i1,.. C.t ~ t ,ilr, the C.~~}~. : '< Sr`~ \.--_~'+;.~"~1,.. ..-...Y`f : layer (103) s'-t ` w{,~S-.:..:~. into F.Yi C.3. .'.

p ;.7.rci l3. tb" of fuse l':.''k /';:i (703, 707, 711) c:: "t "U' i :a:' e areas (701, .". .,, 705, 709) bY' .."c g.~i 'ns of :aubs. 4ci.t"? : ..7.f~.i. ~.:~r less .:: ;a :'f.? :.'t.,.v;t.Y ` i.a:Giss the .'iia':.d;..it.: i-. 'a.v'_,' layer, therL:'.._n sizes of the fuse .."
."S. e ik'?:'s' (703, .__ 5 7:a 7, . ... . ,} and :.aas..~ ...... W c;.s (701, 705, 709) are varied from one .~~.:..3.,.~l1, to -õ== ' 1i.. rf , , -~.:c :.~y +"'.~ another =.;r _.'Y s -,c.\.;.yt~I~ :. (^~ =\ ; , ~.~a...:;::=t~: _1¾. ...~~, heat \ ; 1.. ."..~r."a~.~ ~",?:
.,._: ,.. ,:. õ ''. _ . ".i~ysi -- ..- ~.. :%J:":.;õ> ~." p, C+'F~-,I'_Ã-_ :.n the one reg.E.Cin i._Y.f.l.'3.n the other ...C:'g.}..Lfn upon exposure to I.i?:;.~~.. i~.i .,...... wav%:. C'.ni:a rgSr' .

Brie,~ ~~scri~tir5n of ~~~ ~raw~,~

,"..'tIbod.s..,%' :?tti :?f t;'_e pt { L.ii.t invention will now ,:ie s':.......'u:'i:^.^ed in connection with the '....g';..'e:e. ?yik..`
.>..r.=,:f::.'c"e..ti:'c.''.

.-s:i=7=~ ,y , r ... ... . ,.

I'1; ::T<v rci ... ,.., :_. T;d. cat4? .,. .7. ke e.;, ei"eV i. tt.. iS 3 ., ,.. ,. f.. g;;.X: ess in ::`h;.. C:;.' a s ~ ~
FiLr, -i.,s~a ..~,.,'.~ a:'.ICY. ...f, are conductive structure ~~+':'~"~M..~..~:F...ki :.~:~.., ^ ~~.M.=..~.''.3..~~...~IL.< to .
1r~~..l.~.......:.i:~ "~S'b'='~~....=.(i..w.. of f.....~.. Y >^.. ..
..~~:"i:~.y-`..~, ,.. .., . -. , the . ,.
ii s veni. iont .,.. Fi'Nti .,. i.... a ... `:.'{..t.., ... n of ..h.".~. `:abo..E. :.me:..'.
i,. '../ f .[" .;.... !A4 t=., k: :..., aloF"i " .. ... Y:t:' v., 2;

.. . g ,-. t..., =.'."t ..op v-..'z=!'.' S.Jf a =...o<:Z.::i.Cc=..%.vC' ..it,_ u`t:4.;.%_.: e w...l..C:h :G is b?ei:{ !;.?.v~:':,5.S. . ~~,~ .;.~.L:~.~`.. K'1G't+ ~s,:, w,r .. .E'::i'...,. .'.=''wi' ; f~,~~.~.C*, .~~... "i. is . i . +..... !?C i present the3"t: o. , F' g 4 ...... a : L:}.3.e;i1ct. ti., ... l...':.< ....ra#-. .,. C:=':; ... l:
;i+l chc:i.r'.. : ? f a i.i!et_it.:i4: for ...% f::.L.;;;<:F a conductive 4 .::,`,:1.1L.: ...'}."e in <,'1'.:s:`~.~.:'da'J','.-<..:.. `v`d_.,n ......., !:>w.`~pE::W:i o... ..h':..~ pre:J~~'.'.:lv ...a..'iF.'.nt_..on~

F.S-."= 5 i.. ... L_o~''...:' view f ~''..'::.~3 't.~..". structure ': ?w: .

. ,Y. ' :Ms':' }~ '~~:
i,yiA. a ~.. C,i~;,i:..~.~~..... :_ er~. :^: Si.:.. .".... ~ ~~ - ^`pC~'_.. .
t r. ..i..s.~:^f'.. .~ :.. .s'.F_.' .. r.` .i...:.a. C1le~.=,~{.- ~ . .=..t i~:-~, a c:. :... .i..:it:.-~..~.._..5...~ ~a f >. iJ...-.. ..~~C..i.:, .
- ...C~i3C.
..../ substrate by fuse o:.3:'3..e3.i . ...7.r?Xl;

_ Ag 6 i,/ a top v:-v4t- C>w a ct,ntxÃ:;C v. ,;e stY;zcti<r::

p.tr: t~?~.... ;4Y:.,....... e' ~ :~3i.i...^"'L :.=.,. ~.r.,> ~' Y-'=`::,~ ~
"`~ C:~:-=: :~ :.i.:~. " =.rõ .3 oriented fuse :.3,.. ~~.:;~.:.x~.,. .3.,.?72.a.;.e.:e s...bs': 3." c1 t' by t:'... .-^ i: ,'^l idM '"` .

f. g 7 ........ a t=.:T?; view of C: conductive ... ., r;.',C:.tiir:l i::<:3.tv ,; j ,..':i;,.,`: he:1t :;'.-'`^-`.-=.'e'..=:a.;..7.on is graded from tht, w';,?13.:'_:¾=:r to t_ :: s ' :'.~~.~f 't. f a.:d , g .. :5.... a s".;.r'':'3ct w. ;a. =: rc:':p:"C': s:? : ,:-i3.'::.::: tion of cooking a ,.,i-,od ......[:C.... in a 'b'.'..: a:.'.~:..,''.~,.I}.::: .~:<-} '~/r", ~+r:~:':`.. " .:}. the , ~ : . ...:~. 'ti%. ..L~Epre:-',=t::n-i.:.

i':1 v-:3 ntir=. n.

25) Detailed Deyw ri tio .:'>:sr.i~::t:7.:, . in ~~.`,.':: ~. ..
~ ... . o-..,:Ci~`T3.i....<;:r3~ will ...~... ti~:: . ~~t:,'~,.:-+ ,. ..r :T"(:~=".~5.~:?~'..,C':?''i;. . ..=.. . ~

:.
v... .:: ,^; or ... . .. <.. ., l... o45=i ,. =F3.g +. ;ei:. ':. ._ .:.. pt...
o,., ,: ~ : ia i:~. -.. ;'1 ..._.:f t 1::.>~ ( :3.. C i 3. ~F,~ :,. ~~... ~, ..
.... :: figures>

?7 2 11--:..

ON-M:..., .,.ot<Syave conv`u:,. t..ve .'.''>;...- Ful: ... v.r'.'~~-~w , ..i.n....,..u'.:..i..~f ,,'.f :7~~:"."~'~;3~.,..~,3:~:~~' used in food r~~"~.i..u~~^M ::.L:~it-'~ ..r~' C.f r^ X.. ... ~~.li".
t?%.'.... ,.. ': %~`>y _, '~, .'i<-.: :s:.'s ~.~ 3 .:. . l;=
...3'fi:lv.:`.S.S:..,~ a ..:`-'.,.. <w'.'~:}-.ld'i.r,.t....v`t': substrate ,,Fig. 2, 101i suitable _.C,ir cf.:Y_tG't....., with fS/od, ..... 23jh.,:.'.;.. a C`.o:":d:,.4:i,i1J'"' layer ,., ,. t , i'... 2, 103i is d.....,'~'.`.~po;Y ed. The i:?tr:.i.~.~... i. ure may ,.ie covereC.~t waif:;5.. one or more ....C:ditiC:;ncil layers of 7-aol..- vo?`?d;.ic :3.;:e : f i:..'. t. r' .., ... ... l, C.f"`i "";F.2-?C.~,r: . yf r.. he .:c',.., ' c':; ~ : du... .. ive substrate (F g. 2.

101) tiii.i~.Y. the cti.adt...`.:'., ,3.. v... layer (. : g 2, 103) are laminated to U!
a i:,.nv.e...it3.F.. whose ,.i.._,.:e and shape is more temperature stable, such as paper, paperboard or cellophane (Fig. 2, 201).
Microwave energy impinging on such a structure induces currents within the conductive layer.
The currents are dissipated by the resistance of the conductive layer as heat energy, which may be conducted into food articles placed on or near the structure. The present invention is of this general type.
The present invention is now generally described in connection with Figs. 1 A -1 C.
Fig. 1A shows a fused microwave conductive structure comprised of a paper or plastic substrate, generally designated 101, and a electrically conductive layer, generally designated 103. The layers 101 and 103 may be more clearly seen in the cross-section of Fig. 2.
The structure may be covered with a dimensionally stable material (Fig. 2, 201) of paper, paperboard or cellophane, for example. For clarity, the dimensionally stable material (Fig. 2, 201) is omitted from all top views.
The substrate layer 101 may be made of any plastic conventionally used for food packaging purposes and which is not susceptible to damage during microwave cooking or as a result of the application of a thin film of metal or other conductive material. For example, the substrate may be biaxially oriented polyethylene terephthalate (PET), polyethylene napthalate (PEN), polycarbonate, nylon, polypropylene or another plastic approved for direct food contact.
The conductive layer 103 may be formed of any metal or alloy conventionally used for microwave conductive structures. The conductive layer 103 should have a surface resistivity in a range of about 100/0 to 1000SZ/El. Advantages of the present invention may include, but are not limited to greater or lesser heat flux than current susceptors, safer more uniform heating and lower and higher temperature conductive structures. Suitable metals include aluminum, iron, tin, tungsten, nickel, stainless steel, titanium, magnesium, copper and chromium or alloys thereof.
The conductive layer 103 may include metal oxide or be partially oxidized or may be composed of another conductive material, so as to adjust the layer properties.
Conductive layer 103 is provided with a plurality of non-conductive areas 105, such as apertures or areas of non-conductive materials, conductive base areas 107 and fuse links 109, for example. The fuse links 109 connect base areas 107 each to the other.
The base areas, 107, can be large enough to function individually as inefficient microwave susceptors, but should not be so large as to function individually as efficiently as a conventional sheet susceptor. Alternatively, they can be too small to individually act as microwave susceptors and heat up significantly on exposure to microwave energy. However, a group of such areas, whether large or small, linked together by fuse links 109, converts microwave energy into heat overall similarly to a large conventional susceptor. As will be explained in greater detail, below, heat generation of such a susceptor including fuse links 109 is concentrated to a greater or lesser degree in the fuse links 109, depending upon the geometry of those fuse links 109. As will also be explained in greater detail below, if one area (Fig. 3, 300a) of the susceptor is over-exposed to microwave energy, fuse links in that area will break, isolating that area from other areas (Fig. 3, 300b) of the conductive structure. As a result, those areas (Fig. 3, 300a and 300b) will operate less effectively as a microwave susceptor.

Failure of the fuse links is a function of the supporting substrate, the thickness of the conductive layer 103, the constituent material of the conductive layer, the dimensions of the pattern defining the fuse links 109 and the dimensions of the base areas 107 as well as variables related to the food, the location of the food within the oven cavity and the oven type.
Furthermore, fuse links may develop small cracks that permit displacement currents to flow through the cracks possibly in a capacitive coupling fashion, before failing entirely. This, and other factors, discussed below, permit the design of fast and slow fuses, and high heating and low heating fuses. Pattern dimensions and corresponding fuse link behavior is presently determined on an empirical basis. Fuse links covering an area of about 0.1 mm2 to 20 mmz are suitable.

Hotter susceptors are possible using the present invention, because the sheet resistance of a susceptor constructed with fuses is higher than that of a susceptor constructed of a similar thickness layer of metal, but without fuses. The apertures through the metal layer, which define the fuse links 109 and base areas 107 are non-conductive. Therefore, current flow is restricted to the areas of the fuse links 109 and base areas 107. This restriction of current flow is due to an effectively higher sheet resistance. The sheet resistance of a susceptor is also related to the surface impedance of the susceptor at the frequencies of operation in microwave ovens, and power transfer from one transmission medium to another depends upon the matching of the impedances from one medium to another. The impedance of air is relatively high at the frequencies of interest. Therefore, by raising the sheet resistance of the susceptor and consequently raising the surface impedance, a better match to the air is achieved. Thus, more power is transferred into the susceptor, which converts the microwave energy received into heat.
By orienting the fuses to avoid placement along the axis of greatest stretch of the substrate, the fuses may be set for a higher heat, without breaking, than would be achieved by a conventional susceptor, which would begin to break when the recoil forces began to rupture the film.

Cooler susceptors are also possible using the present invention. Fuses break when the local temperature reaches the temperature at which the substrate recoil force grows large enough to break the fuse. The fuses may be set to break at relatively low susceptor surface average temperatures, thus limiting the overall heat generated by the susceptor structure, by making the fuses relatively small. A cooler susceptor may use relatively small base areas, for example about 2 - 3 mm on a side, having a relatively heavy deposition of metal, for example reaching an optical density of about 0.45. In a conventional susceptor, such a thick layer of metal would be subject to relatively rapid, uncontrolled breakage, due to rapid heating from high currents generated. However, the fused susceptor according to the present invention would break down in a controlled fashion, at a controlled temperature. By using small, thick base areas, the susceptor could continue to operate at a lower efficiency, providing a low, but steady heat to the food.
The present invention, when embodied as described above using a relatively thick metal layer, is advantageously used in a bag or wrap configuration, as shown schematically in Fig. 8, with the food 801 placed in the center. In such an application, the relatively thick metal layer reflects some of the microwave energy impinging on it 803. An additional quantity of microwave energy 805 is absorbed by the metal layer and converted to heat 807 which is conducted to the food surface. A small remaining quantity of microwave energy 809 passes through the metal layer to cook the interior of the food. Such operation is particularly suitable for food items which are susceptible to overcooking by microwave and which require crisping or browning at high temperature, such as filled pastries and some meats.

A number of patterns have been proposed. For example, the patterns shown in Figs. 1 B
and 1 C will produce different degrees of heating of food articles and fuse links, both before and after fuse links break. The pattern of Fig. 1B may be characterized as having slow, hot fuses 109, whereas the pattern of Fig. 1 C may be characterized as having fast, cool fuses 109. This difference in fuse behavior arises as follows.
Fuse links function as conventional fuses; that is, a fuse with a larger conductive cross-section than a second fuse requires greater current to fail than that required to make the second fuse to fail. With the same conductive layer thickness, wider fuse links having corresponding larger cross-sectional areas and connecting adjacent base areas, fail at higher temperatures than narrower fuse links due to increased current capacity. These wider fuse links also take longer to reach failure temperature. In Fig. 1B, the fuse is wider than the distance between opposite edges of the adjacent non-conductive area, resulting in a slow, hot fuse. In Fig. 1C, the fuse is narrower than the distance between opposite edges of the adjacent non-conductive area, resulting in a fast, cool fuse, because the current carrying capacity of the fuse is decreased. The fuse design rules discussed with respect to these patterns are applied to make fuse breakage uniform across the structure as described later.

In Fig. 3, the effect of irregularly shaped food articles on a conductive structure according to the present invention is seen. Food articles 301, shown in phantom, are placed on a conductive structure 303, in accordance with the present invention. Fuse links 305, 307 and 309 are exposed directly to microwave energy. Therefore, they break, isolating portions 300a and 300b of the conductive structure 303 from one another. The microwave energy absorbed in the region near broken fuse links 305, 307, 309 and subsequently converted into heat is reduced.
Fuse link 311, being partially covered by a food article 301 has partially broken. Thus, microwave heating of those areas of conductive structure 303 has been partially reduced. Since less microwave energy is absorbed by the regions of conductive structure 303 where fuses have broken, the solid regions of conductive structure 303 under food articles 301 now absorb relatively more microwave energy and produce more heat. Therefore, the effectiveness of conductive structure 303 in the areas covered by food articles 301 has been enhanced.

In addition to the variables discussed above, failure of the fuse links is a function of the relationships between non-conductive areas 105, fuse links 109 and base areas 107 and the polymeric substrate (Fig. 2, 101), as now discussed.

A biaxially oriented polyethylene terephthalate (PET) film is a polymeric film which has been stretched in two orthogonal directions. The two directions are usually the machine direction, i.e., the direction of film travel, and the across-the-web direction, i.e., perpendicular to the machine direction. Stretching a crystalline or partially crystalline film and then rapidly cooling or quenching the film imparts several beneficial physical characteristics to the film such as increased strength and yield (measured in square inches of film produced per pound of raw material). Typically the film is stretched more in one direction than the other. However, if the oriented film is brought above its orientation temperature, then it tends to shrink to its former size. Such films exhibit a greater recoiling or shrinkage force in the direction of greater stretch than in the other direction. The shrinkage is due to the stretched polymer chains recoiling, much like springs. Shrinkage can cause the PET film to rupture, and a small rupture can propagate.
Ruptures and tears may disrupt susceptor operation by isolating some areas from others, resulting in uneven heating. In some cases, there may be excess heat build up in localized regions.

Consider a fuse susceptor pattern, as shown in Figs. 1 A, 1 B or 1 C deposited on a typical biaxially oriented film with all fuses being the same size and shape, and with fuses being aligned with the film's directions of stretch. When exposed to microwave energy, the fuses arranged between base areas aligned in the direction of greatest stretch will break before fuses aligned with direction of lessor stretch, due to the difference in recoil force generated upon heating.
However, the fuse links of a fuse susceptor pattern, shown in Fig. 5, having its axes aligned 45o to the machine and across-the-web directions will break at substantially the same time, when illuminated with approximately the same quantity of electromagnetic energy, everything else also being equal. Furthermore, since the recoil force exerted upon the fuses aligned as described is less than conventionally aligned fuses, otherwise equivalent fuses aligned as described will break at a somewhat higher temperatures.
Alternatively, in order to cause fuse links to break at substantially the same time after the same exposure to microwave energy, the fuse links could be aligned with the machine and across-the-web directions, as previously done, but with fuse links sized to compensate for the different shrinkage forces in the film as shown in Fig. 6. In Fig. 6, to increase their current carrying capacity, fuse links 601, aligned in the across-the-web direction are wider than fuse links 603, aligned in the machine direction.
Advantages of the present invention may include, but are not limited to, greater heat flux than current susceptors, safer, more uniform heating and achievement of both lower temperature and higher temperature conductive structures. By varying the fuse dimensions, different heating characteristics may be achieved. Small hot fuses may be made, which do not rupture the PET
substrate, because they are not oriented on the weak axis of the substrate.
Conversely, large cooler fuses which generate very uniform temperatures may be made, because the break points of fuses are made uniform by use of the invention. Aligning the fuse links at a 45o angle with the film's orientation directions, as shown in Fig. 5, directs the current and hence the heating away from the weakest direction of the polymeric substrate, resulting in a more robust fuse susceptor.
The fuse links begin to break at higher temperatures than similar dimension fuses oriented with the direction of greatest stretch.
The pattern of Fig. 7 includes these distinct regions, whose fuses and base areas have differing geometries. The center region is designed to have small base areas 701 and proportionally large, hot fuses 703. Thus, the center region provides the greatest heating effect to the food. The fuses 703 of the center region provide a safety mechanism which prevents overheating of this hot region. The middle band has somewhat larger base areas 705 than the center region, but the fuses 707 are a relatively smaller proportion of the size of the base areas 705 than in the center region. These design choices provide somewhat less heat than the center region, because the fuses 707 break at a lower temperature than fuses 703, but the base areas 705 nevertheless remain operative at a reduced efficiency after fuses 707 break.
In the outer region are found the largest base areas 709 and the proportionally smallest fuses 711. As a result, the outer region provides the lowest heat generation. When the fuses 711 break, which here occurs at the lowest temperature, the base areas 709 operate as susceptors, but at a reduced efficiency.
Thus, this design directs the greatest heat to the food region, while the edges remain somewhat cooler.

The material described in connection with Fig. 7 is particularly suitable for cooking foods like pizza, when made as described in connection with Fig. 8. Where food is in proximity with the susceptor material, the fuses tend not to break, but to continue to produce heat. Thus, the middle part of the pizza dough may be crisped, without burning the edges.

Conductive structures in accordance with the present invention may be made by a variety of methods known to those skilled in the art. In general, any method which can produce a thin pattern film of metal on a plastic substrate is suitable. For example, pattern printing and etching techniques are suitable. Another such method is now described in connection with Fig. 4.

In accordance with this method, there is supplied from a supply reel 401 a continuous web of plastic substrate 403. The plastic substrate 403 is passed between rollers 405 and 407 which cause to be printed on a bottom surface thereof a negative image in oil of the desired pattern.
The plastic substrate 403 then passes above an aluminum deposition apparatus 409. The pattern of oil printed by rollers 405 and 407 locally prevents deposition of metal.
Metal is, however, deposited to regions not covered by the oil. Thus, take-up reel 411 receives a substrate on which a conductive structure film has been deposited having, for example, one of the patterns shown in Figs. lA-1 C.

Another example of a method for producing conductive structures according to the present invention is to deposit a uniform film of metal on a substrate and subsequently etch metal away to form the pattern required.

The present invention has now been described in connection with a number of specific embodiments thereof. However, numerous modifications which are contemplated as falling within the scope of the present invention should now be apparent to those skilled in the art.

Therefore, it is intended that the scope of the present invention be limited only by the scope of the claims appended hereto.

Claims (8)

-11-
1. A fused susceptor structure including a non-conductive substrate (101); and a conductive layer (103) disposed on the non-conductive substrate (101);
CHARACTERIZED BY:
the conductive layer (103) divided into a plurality of fuse links (109) and base areas (107) by regions (105) of substantially less conductivity than the conductive layer (103); wherein the fuse links (109) are arranged in at least two orientations, and the fuse links (109) of both orientations are equally susceptible to breaking upon exposure to microwave energy.
2. The fuse susceptor structure of claim 1, wherein the non-conductive substrate is:
a biaxially oriented substrate film.
3. The fuse susceptor structure of claim 2, wherein the substrate film has a greater shrinkage force along a first axis as compared to the shrinkage force along a second axis.
4. The fuse susceptor structure of claim 3, wherein the the fuse links have axes forming oblique angles with the axes of the substrate film.
5. The fuse susceptor structure of claim 3, wherein fuse links (601) oriented along the first axis are larger than fuse links (603) oriented along the second axis.
6. The fuse susceptor structure of claim 1, wherein the conductive layer is a layer of metal having an optical density substantially equal to 0.45.
7. A.Fused susceptor structure including a non-conductive substrate (101); and a conductive layer (103) disposed on the non-conductive substrate (101);
CHARACTERIZED BY:

the conductive layer (103) divided into a plurality of fuse links (703, 707, 711) and base areas (701, 705, 709) by regions of substantially less conductivity than the conductive layer, wherein sizes of the fuse links (703, 707, 711) and base areas (701, 705, 709) are varied from one region to another region to cause greater heat generation in the one region than the other region upon exposure to microwave energy.
8. The fused susceptor of claim 7, wherein the base areas (701) near a center of the susceptor are smaller than the base areas (709) near an edge of the susceptor.
CA002211071A 1995-05-01 1996-04-29 Multilayer fused microwave conductive structure Expired - Fee Related CA2211071C (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US08/432,492 US5530231A (en) 1994-01-25 1995-05-01 Multilayer fused microwave conductive structure
US08/432,492 1995-05-01
PCT/US1996/005939 WO1996034810A2 (en) 1995-05-01 1996-04-29 Multilayer fused microwave conductive structure

Publications (2)

Publication Number Publication Date
CA2211071A1 CA2211071A1 (en) 1996-11-07
CA2211071C true CA2211071C (en) 2003-12-23

Family

ID=23716389

Family Applications (1)

Application Number Title Priority Date Filing Date
CA002211071A Expired - Fee Related CA2211071C (en) 1995-05-01 1996-04-29 Multilayer fused microwave conductive structure

Country Status (8)

Country Link
US (1) US5530231A (en)
EP (1) EP0824482B1 (en)
JP (1) JPH11504597A (en)
AT (1) ATE180741T1 (en)
CA (1) CA2211071C (en)
DE (1) DE69602746T2 (en)
ES (1) ES2133961T3 (en)
WO (1) WO1996034810A2 (en)

Families Citing this family (62)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6054698A (en) 1996-11-01 2000-04-25 Mast; Roy Lee Microwave retaining package for microwave cooking
DE69819419T2 (en) * 1997-01-29 2004-10-07 Graphic Packaging Corp MICROWAVE OVEN WITH SEVERAL HEATING ELEMENTS ARRANGED IN A LOOP
US6414290B1 (en) * 1998-03-19 2002-07-02 Graphic Packaging Corporation Patterned microwave susceptor
US6488973B1 (en) 1998-10-05 2002-12-03 Food Talk, Inc. Method of making a cooking pouch containing a raw protein portion, a raw or blanched vegetable portion and a sauce
US6433322B2 (en) 1999-09-20 2002-08-13 Graphic Packaging Corporation Abuse-tolerant metallic packaging materials for microwave cooking
US6204492B1 (en) * 1999-09-20 2001-03-20 Graphic Packaging Corporation Abuse-tolerant metallic packaging materials for microwave cooking
US6501059B1 (en) 1999-09-27 2002-12-31 Roy Lee Mast Heavy-metal microwave formations and methods
NL1014512C2 (en) 2000-02-28 2001-08-29 Dsm Nv Method for welding duplex steel.
US6683289B2 (en) 2001-10-29 2004-01-27 Mars Incorporated Hand-held food package
US6710315B2 (en) 2001-10-29 2004-03-23 Mars Incorporated Hand-held food package
US6744028B2 (en) 2001-10-29 2004-06-01 Mars Incorporated Semi-rigid hand-held food package
US6677563B2 (en) 2001-12-14 2004-01-13 Graphic Packaging Corporation Abuse-tolerant metallic pattern arrays for microwave packaging materials
GB0221099D0 (en) * 2002-09-12 2002-10-23 Qinetiq Ltd Microwavable packaging material
EP1701897B1 (en) * 2004-01-08 2008-11-26 Food Talk, Inc. Flexible microwave cooking pouch containing a raw frozen protein portion and method of making
WO2006048412A1 (en) 2004-11-08 2006-05-11 Freshpoint Holdings Sa Time-temperature indicating device
US20060118552A1 (en) * 2004-12-02 2006-06-08 Campbell Soup Company Use of shielding to optimize heating of microwaveable food products
US20110204046A1 (en) * 2005-05-25 2011-08-25 Middleton Scott W Microwave Heating Construct for Frozen Liquids and Other Items
US7196299B2 (en) * 2005-06-02 2007-03-27 Schwan's Food Manufacturing, Inc. Elevated microwaveable carton and susceptor portion and methods
CA2612088C (en) 2005-06-17 2012-05-15 Graphic Packaging International, Inc. Susceptors capable of balancing stress and effectiveness
US7687748B2 (en) 2005-08-01 2010-03-30 Western Industries, Inc. Induction cook top system with integrated ventilator
JP4964947B2 (en) * 2006-04-27 2012-07-04 グラフィック パッケージング インターナショナル インコーポレイテッド Multi-directional fuse susceptor
US9205968B2 (en) 2006-04-27 2015-12-08 Graphic Packaging International, Inc. Multidirectional fuse susceptor
WO2007146651A2 (en) 2006-06-14 2007-12-21 The Glad Products Company Microwavable bag or sheet material
US8461499B2 (en) 2006-06-14 2013-06-11 The Glad Products Company Microwavable bag or sheet material
US20080008792A1 (en) * 2006-06-27 2008-01-10 Sara Lee Corporation Microwavable food product packaging and method of making and using the same
CA2676047A1 (en) * 2007-02-08 2008-08-14 Graphic Packaging International, Inc. Microwave energy interactive insulating sheet and system
US8338766B2 (en) 2007-08-31 2012-12-25 The Hillshire Brands Company Microwaveable package for food products
WO2009046053A2 (en) * 2007-10-03 2009-04-09 Graphic Packaging International, Inc. Microwave heating sleeve
US8247750B2 (en) * 2008-03-27 2012-08-21 Graphic Packaging International, Inc. Construct for cooking raw dough product in a microwave oven
BRPI0913415B1 (en) 2008-06-04 2019-09-10 Gordhanbhai Nathalal Patel indicator system
AU2009256212B2 (en) 2008-06-04 2015-12-10 Jp Laboratories Inc. A monitoring system based on etching of metals
ES2571215T3 (en) * 2008-06-09 2016-05-24 Graphic Packaging Int Inc Interactive structure with microwave energy with micro openings
EP2150091B1 (en) * 2008-07-31 2012-06-27 Graphic Packaging International, Inc. Microwave heating apparatus
US8663758B2 (en) 2008-09-09 2014-03-04 Frito-Lay North America, Inc. Partially metallized film having barrier properties
EP2365929A4 (en) * 2008-09-17 2014-03-19 Graphic Packaging Int Inc Construct for browning and crisping a food item in a microwave oven
US20110024413A1 (en) * 2008-09-17 2011-02-03 Cole Lorin R Construct for Browning and Crisping a Food Item in a Microwave Oven
US8815317B2 (en) 2009-01-12 2014-08-26 Graphic Packaging International, Inc. Elevated microwave heating construct
US20100195939A1 (en) * 2009-01-26 2010-08-05 Sterling Tucker Multi-layer laminated film for making a retail-ready microwave oven cooking pouch
CA2749377C (en) * 2009-02-23 2014-07-29 Graphic Packaging International, Inc. Low crystallinity susceptor films
US20100213192A1 (en) * 2009-02-23 2010-08-26 Middleton Scott W Plasma Treated Susceptor Films
US20110011854A1 (en) * 2009-02-23 2011-01-20 Middleton Scott W Low crystallinity susceptor films
US9284108B2 (en) 2009-02-23 2016-03-15 Graphic Packaging International, Inc. Plasma treated susceptor films
WO2010123790A2 (en) 2009-04-20 2010-10-28 Graphic Packaging International, Inc. Multilayer susceptor structure
JP5559307B2 (en) 2009-04-28 2014-07-23 グラフィック パッケージング インターナショナル インコーポレイテッド Method for heating, scorching and / or crispy finishing of food in a microwave oven using an aerated susceptor structure
JP6099395B2 (en) 2009-07-30 2017-03-22 グラフィック パッケージング インターナショナル インコーポレイテッドGraphic Packaging International,Inc. Low crystallinity susceptor film
JP5535332B2 (en) * 2009-11-30 2014-07-02 グラフィック パッケージング インターナショナル インコーポレイテッド Microwave heating structure having a ventilation mechanism
US8604401B2 (en) * 2009-12-09 2013-12-10 Graphic Packaging International, Inc. Deep dish microwave heating construct
US8809754B2 (en) * 2010-03-11 2014-08-19 Graphic Packaging International, Inc. Microwave heating package for frozen food items
WO2011126751A2 (en) * 2010-03-29 2011-10-13 Graphic Packaging International, Inc. Microwave heating apparatus with food supporting cradle
CA2813421A1 (en) 2010-10-21 2012-04-26 Graphic Packaging International, Inc. Substantially round tray
WO2012148895A2 (en) 2011-04-25 2012-11-01 Graphic Packaging International, Inc. Microwave energy interactive pouches
CA2910074C (en) 2013-05-24 2018-07-24 Graphic Packaging International, Inc. Package for combined steam and microwave heating of food
MX2017001400A (en) 2014-08-01 2017-05-03 Graphic Packaging Int Inc Microwave packaging.
US10336500B2 (en) 2014-11-07 2019-07-02 Graphic Packaging International, Llc Tray for holding a food product
US10232973B2 (en) 2014-11-07 2019-03-19 Graphic Packaging International, Llc Tray for holding a food product
EP3261942B1 (en) 2015-02-27 2019-12-18 Graphic Packaging International, LLC Container with coating
US10479584B2 (en) 2015-10-15 2019-11-19 Graphic Packaging International, Llc Microwave packaging
MX2019000729A (en) 2016-07-22 2019-05-02 Graphic Packaging Int Llc Container with liner.
CN110169200B (en) * 2017-01-10 2021-10-19 松下电器产业株式会社 Electromagnetic field distribution adjusting device and microwave heating device
CN112566850A (en) 2018-08-07 2021-03-26 印刷包装国际有限责任公司 Lined container
AU2021376346A1 (en) 2020-11-06 2023-05-18 Graphic Packaging International, Llc Tray for food products
USD1004431S1 (en) 2022-02-08 2023-11-14 Graphic Packaging International, Llc Tray

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4320274A (en) * 1980-01-14 1982-03-16 Rte Corporation Cooking utensil for uniform heating in microwave oven
US4883936A (en) * 1988-09-01 1989-11-28 James River Corporation Control of microwave interactive heating by patterned deactivation
EP0440792B1 (en) * 1987-10-05 1993-09-15 Toyo Seikan Kaisha, Ltd. Sealed container for cooking in microwave range
CA1313231C (en) * 1987-11-18 1993-01-26 Richard M. Keefer Microwave heating
US5220143A (en) * 1988-05-23 1993-06-15 The Pillsbury Company Susceptors having disrupted regions for differential heating in a microwave oven
US4904836A (en) * 1988-05-23 1990-02-27 The Pillsbury Co. Microwave heater and method of manufacture
US5173580A (en) * 1990-11-15 1992-12-22 The Pillsbury Company Susceptor with conductive border for heating foods in a microwave oven
US5185506A (en) * 1991-01-15 1993-02-09 Advanced Dielectric Technologies, Inc. Selectively microwave-permeable membrane susceptor systems
US5260537A (en) * 1991-06-17 1993-11-09 Beckett Industries Inc. Microwave heating structure
US5294765A (en) * 1991-06-26 1994-03-15 Hunt-Wesson, Inc. Perforated susceptor for microwave cooking
GB9114068D0 (en) * 1991-06-28 1991-08-14 Beckett Ind Inc Microwave heating device
GB9201932D0 (en) * 1992-01-29 1992-03-18 Beckett Ind Inc Novel microwave heating structure
US5412187A (en) * 1994-01-25 1995-05-02 Advanced Deposition Technologies, Inc. Fused microwave conductive structure

Also Published As

Publication number Publication date
ES2133961T3 (en) 1999-09-16
DE69602746T2 (en) 1999-10-07
CA2211071A1 (en) 1996-11-07
JPH11504597A (en) 1999-04-27
ATE180741T1 (en) 1999-06-15
DE69602746D1 (en) 1999-07-08
US5530231A (en) 1996-06-25
EP0824482A1 (en) 1998-02-25
EP0824482B1 (en) 1999-06-02
WO1996034810A2 (en) 1996-11-07

Similar Documents

Publication Publication Date Title
CA2211071C (en) Multilayer fused microwave conductive structure
EP0741660B1 (en) Fused microwave susceptor
US5185506A (en) Selectively microwave-permeable membrane susceptor systems
CA2250434C (en) Microwave oven heating element having broken loops
US5350904A (en) Susceptors having disrupted regions for differential heating in a microwave oven
US9764887B2 (en) Even heating microwavable container
US4948932A (en) Apertured microwave reactive package
EP0451144B1 (en) Shrinkable, conformable microwave wrap
US5254821A (en) Selectively microwave-permeable membrane susceptor systems
WO2001023275A1 (en) Patterned microwave susceptor
US10683156B2 (en) Microwave heating container
US8247750B2 (en) Construct for cooking raw dough product in a microwave oven
US20040173607A1 (en) Article containing microwave susceptor material
JP2774342B2 (en) Susceptor with split area for differential heating in microwave oven
EP1590264A1 (en) Microwave susceptor packaging material

Legal Events

Date Code Title Description
EEER Examination request
MKLA Lapsed

Effective date: 20150429