NONSTICK COOKWARE MATERIALS, AND METHODS FOR MANUFACTURE AND USE
20210196077 · 2021-07-01
Assignee
Inventors
- William Christopher LEWIS (St. Charles, IL, US)
- Barton R. LEWIS, JR. (Algonquin, IL, US)
- Paul A.E. SMITH (Cary, IL, US)
- Kevin Patrick DUNLEA (Cary, IL, US)
- Michael BAKER (Petersburgh, NY, US)
- William James LEWIS (Naples, FL, US)
- Barton Roy LEWIS (Algonquin, IL, US)
- Jian GAO (St. Charles, IL, US)
- Lambert Allen TERPSTRA (Crystal Lake, IL, US)
Cpc classification
B32B27/322
PERFORMING OPERATIONS; TRANSPORTING
B32B37/10
PERFORMING OPERATIONS; TRANSPORTING
A47J37/108
HUMAN NECESSITIES
B32B27/12
PERFORMING OPERATIONS; TRANSPORTING
B32B2255/10
PERFORMING OPERATIONS; TRANSPORTING
B05D2203/30
PERFORMING OPERATIONS; TRANSPORTING
B32B3/08
PERFORMING OPERATIONS; TRANSPORTING
B05D5/083
PERFORMING OPERATIONS; TRANSPORTING
International classification
A47J36/02
HUMAN NECESSITIES
A47J37/10
HUMAN NECESSITIES
B32B27/12
PERFORMING OPERATIONS; TRANSPORTING
Abstract
Heat resistant and/or nonstick polymer materials and composites, and cookware including a food support surface comprising an integrated or attached cooking surface formed of the materials and composites. The cookware can includes a melt-processible fluoropolymer surface or insert. The cookware can further include a laminate material with structural rigidity, wherein the laminate material includes a flexible substrate impregnated with the heat resistant polymer material, coated with a nonstick coating, and pressed or molded in a shaped cookware or other nonstick items or component. Various cooking devices can be pressed from the material, as well as oven or vehicle components.
Claims
1. Cookware for holding food items during cooking, including a food support surface comprising an integrated or attached cooking surface formed of a heat resistant polymer material.
2. The cookware according to claim 1, wherein the heat resistant polymer material comprises a melt-processible fluoropolymer, preferably a perfluoroalkoxy alkane (PFA), TFE/perfluoromethylvinylether copolymer (MFA), or fluorinated ethylene propylene (FEP), homopolymer or copolymers of PTFE, or combinations of such fluoropolymers.
3. The cookware according to claim 1, wherein the cooking surface comprises a spray or dip polymer coating, wherein the spray or dip polymer coating is covered and/or laminated with a casted or laminate film of the heat resistant polymer material, wherein the spray or dip polymer coating and the film interlock together during curing.
4. (canceled)
5. The cookware according the claim 3, further comprising a laminate material with structural rigidity, wherein the laminate material includes a flexible substrate impregnated with the, heat resistant polymer material, coated with a nonstick coating, and pressed or molded in a shaped cookware or other nonstick items or component.
6. (canceled)
7. The cookware according to claim 5, wherein the cookware is pressed or molded in the form of a basket, tray, sheet, pan, bowl or cup, plate, cover, or other cookware accessory, and the cookware is fully free of metal.
8. (canceled)
9. The cookware according to preceding claims claim 7, wherein the cookware can withstand temperatures over 375° F. (191° C.) for an indefinite period of time, and more preferably 500° F. (260° C.) for an indefinite period of time and most preferably being able to withstand temperatures of up to 600° F. (315° C.), and up to 800° F.
10. The cookware according to one of the preceding claims claim 1, wherein the cooking surface is clipped, snapped, or press-fit to the cookware around an upper edge of the cookware and extends over the food support surface.
11. The cookware according to claim 1, wherein the cooking surface comprises a separately formed cooking surface insert of the heat resistance polymer material, applied as or over the food support surface of the cookware, wherein the surface insert is replaceable and/or preferably recyclable.
12. The cookware according to claim 11, wherein the cooking surface insert comprises a snap on nonstick cover, wherein an edge of the nonstick cover is configured to snap around an edge of the cookware that is disposed about the food support surface.
13. The cookware according to claim 1, further comprising: a cooking support including a support frame having side walls defining a cooking area, and an inner support structure configured to receive and support a removable cooking insert; and a removable and replaceable cooking insert adapted to be inserted into the cooking support and on the inner support structure, wherein the cooking insert includes the cooking surface and receives the food items during cooking.
14. The cookware according to claim 13, wherein the inner support structure comprises support bars that extend into and between opposing pairs of openings in the side walls, and the cooking insert is suspended between parallel pairs of the support bars.
15-19. (canceled)
20. The cookware according to claim 14, wherein the support frame and/or the cooking insert comprises a basket, tray, pan, and/or a cup extending between upper edges of the side walls.
21. The cookware according to claim 20, wherein the tray and/or the cup includes a curled edge that snaps or clips over an upper edge of the side walls.
22. The cookware according to claim 20, wherein the tray and/or the cup includes a hole that fits over a post on an upper perimeter edge of the side walls.
23. The cookware according to claim 20, wherein the tray includes an opening for receiving the cooking insert, wherein an extension of the cooking insert sets on an upper surface of the tray when the insert is inserted into the opening.
24. The cookware according to claim 23, wherein the cooking insert is formed of natural pulp materials.
25. A replaceable cooking surface or insert for the food support surface according to claim 1.
26. A use of the replaceable cooking surface of claim 25, comprising removing and replacing the cooking surface or insert.
27. A method comprising providing a removable and replaceable cooking surface or insert for a cookware according to claim 1, which is separate from and adapted to be removably secured within the cookware for holding food items during cooking in an oven, wherein the cooking surface or insert is formed of a heat resistant polymer.
28-29. (canceled)
30. The method of claim 27 further comprising a subscription service for regular replacement and recycling of the cooking surface or insert.
31-38. (canceled)
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE INVENTION
[0043] The invention provides heat resistant and/or nonstick materials, and products thereof, including cookware including at least a non-stick polymer cooking surface. As used herein, cookware includes, without limitation, various pots, pans, sheets and baskets, and bakeware such as cake/bread pans and cooking sheets, etc., and also components for cooking devices/appliances. The cookware includes a non-stick cooking surface formed of, or otherwise covered/coated by, a polymer material. Suitable polymer materials include, without limitation, silicone and fluoropolymer materials.
[0044] The invention includes improved heat resistant materials and products, such as vehicle components and cookware, particularly for use in high speed, rapid cook, and/or high temperature conventional ovens. In several preferred embodiments, the products are fully made of a polymer material, and substantially or completely free of metal, and thus nonmetallic. Any suitable high heat resistant polymer can be used, as described above. References to “non-metallic” means that the entire product, and/or each layer or element, is devoid of metal.
[0045] In embodiments of this invention, the cookware and/or cooking surface polymer material is a heat resistant polymer. As used herein, “heat resistant” refers to the ability of a material to withstand continuous-use temperatures of about 400° F. (about 204° C.) or greater. The heat resistant polymer can be neat or reinforced, and can include, for example, a fluoropolymer (e.g., PTFE, FEP, PFA, MFA®, ETFE), a fluoroelastomer, a silicone rubber, a silicone resin, a urethane rubber, a urethane resin, a polyketone, a polyether ether ketone (PEEK), a polyimide-imide (PAI), a polyphenylene sulfide (PPS), a polyphenylsulfone (PPSU), a liquid crystal polyester (LCP), a polyether sulfone (PES), an epoxy, quartz, fluorinated materials, such as fluorinated mica, combinations thereof, and/or other nonstick, easy clean materials.
[0046] To form products of embodiments of this invention, pelletized glass-filled or other polymer material can be melted in a screw extruder and then molded in any suitable molding process to obtain the cookware form. Exemplary molding processes include, without limitation, injection molding, stamping, and/or thermoforming, desirably to form the integral cookware piece. Additives can also be included to promote desirable properties. Exemplary additives include materials that reduce the thermal mass and enable rapid cooling, such as hollow glass spheres, chopped fiberglass, mica, etc.
[0047] In embodiments of this invention, the product is formed from or including a melt-processible fluoropolymer. Exemplary melt-processible fluoropolymers include, without limitation, perfluoroalkoxy alkanes (PFA) or fluorinated ethylene propylene (FEP), homopolymers or copolymers of PTFE, or combinations thereof. In embodiments of this invention, an entire cookware, or at least cooking sections/surfaces thereof (e.g., for cooking surface coatings or add-on handles, etc.), are molded from the melt-processible fluoropolymers. Exemplary embodiments have a 20 mils or greater thickness, and can hold the molded shape during cooking cycles in high temperature ovens.
[0048] Embodiments of this invention provide or include a polymer surface covers or insert, particularly for cookware items, also desirably formed of a melt-processible fluoropolymer. Due to the cost of, for example, melt-processible fluoropolymers, the surface inserts provide a thin, snap on and or draping (capping) cover material for providing metal or polymer cookware with nonstick properties, and/or reconditioning older cookware.
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[0051] The cooking surface inserts of embodiments of this invention apply over cooking/baking food support surfaces of the cookware, such as by clipping, snapping, press fit, or otherwise being nested, and are desirably replaceable and recyclable. The insert can be applied to new types of cookware (e.g.,
[0052] The present invention further provides an improved woven/plastic/nonstick composite or laminate material with structural benefits, and that is pressable or otherwise moldable in a forming method to provide shaped cookware, cooking surface inserts, or other nonstick items/components. Embodiments of the material composite of this invention can incorporate 100% engineered resin as the plastic material until the woven glass substrate is sufficiently saturated such that, when molded, the engineered resin is consolidated to create a structural component. Another feature is that the invention desirably bonds the fluoropolymer or silicone to the 100% engineered resin. This is easily done and with good bond strength. Embodiments of this invention provides high temperature (≥375° F.) resistant, formable composites. As shown in
[0053] Various and alternative sizes, shapes, and configurations are available for the plastic impregnated/coated substrate. For example, more than one substrate layer can be impregnated. In addition, more than one separately impregnated substrate can be laminated together prior to top coating. The multiple layers can be the same or different substrate materials, such as, for example, a coated woven can be laminated to a coated nonwoven on one or both sides. The type and number of layers can be adjusted for rigidity, depending on need. For example,
[0054] A nonstick coating 56, such as of the materials disclosed herein, is applied over top of the engineered thermoplastic coating 54. The nonstick coating 56 is desirably capable of being easily cleaned, and is chemical resistant, abrasion resistant, and stain resistant. Exemplary nonstick materials include fluoropolymers and silicone rubbers and resins. Once formed, the composite material can desirably withstand temperatures of greater than 375° F. (191° C.) continuous, and up to 800° F. (426° C.), depending upon the engineered resin utilized.
[0055] The nonstick coating 56 can be applied over the engineered resin 54 by, for example, dip, spray, curtain, or powder coating. The nonstick coating 56 surface can be applied by laminating a cast, extruded, skived, or PTFE coated fabric to the surface of the engineered resin. The nonstick coating 56 can be applied before forming or after forming a molded part, described further below.
[0056] In embodiments of this invention, a microwave absorbent material or coating 58 can be applied before the nonstick coating 56 is applied, or as a component of the nonstick surface application. As with the nonstick coating 56 application, this can be applied as a coating or laminated material, in same manner as mentioned above.
[0057] The composite materials of embodiments of this invention are useful in forming molded objects, such as consumer goods and cookware. According to some embodiments of this invention, the forming process begins with a substrate, such as a woven fiberglass substrate, which can include plies of coated linear strand fiberglass. The substrate is saturation coated with a solution of dissolved or suspended plastic, such as PAI, PPS, PEEK, PPSU, PES, or combinations thereof, or other suitable plastics known for high temperature use. Multi-pass applications of the coating can be used to adequately saturate the fibers, and build adequate weight for flow and forming. The plastic coated substrate is preferably dried and prepared to a pre-preg (pre-impregnated) condition, similar to that performed for epoxy resins on fiberglass used in printed circuit boards.
[0058] A top coat of PTFE or other nonstick material is applied to one or both sides. The fluoropolymer coating provides mold release functionalities during forming, and provides a high performance release finish for cooking (similar to pan coatings). The coating can be applied by, for example, a heavily coated single ply coating and/or multi-ply lamination of lighter weight woven or linear strand fiberglass.
[0059] The dried, but not cured, composite material can be wound into a roll and stored for further processing from the roll into an automated forming press, or sheeted to discrete sizes for manually loading into a press. The forming presses typically include heated platens to which male and female forming dies are attached, with temperatures generally adjustable to 600° F. (315° C.) or higher. The material is formed at a temperature at or above the glass transition temperature (Tg) of the blended engineered resins. Pressures are also generally adjustable and vary according to size. Testing has shown reasonable results as low as 30 psi in an air load press capable of 3 tons total applied pressure. Larger part sizes and multiple part molds may require significantly more pressure. Matched form molds, or coining, is a form of compression molding requiring higher pressures; for proposed objects of this invention, 30- to 50-ton hydraulic presses are likely needed.
[0060] After forming the edges may be trimmed in a die cutting station, such as “steel rule die” or “clicker press”. The formed parts are post cured in a batch oven with a stepped temperature cycle to obtain higher operating temperatures and to cure the PTFE and enhance the bond of the PTFE to the tray. The post forming processing can be used to crosslink, chain extend, or otherwise cure the engineered polymer. Also, the engineered polymer could be post-cured to temperatures capable of fusing fluoropolymers.
[0061] In embodiments of this invention, the material can be cured during the molding process if molding is done at high enough temperature. Another option is to post cure in an inline process such as a hot air or infrared oven on a conveyor. In embodiments of this invention, molding is performed between 640° F. (338° C.) and 800° F. (426° C.). At these temperatures, the process can complete and no post cure is needed. The higher temperature allows the fluoropolymer to cure at a same time as molding and thus reduces the need for post cure.
[0062] In embodiments of this invention the composite is formed including a woven substrate of a high temperature thermoplastic material (e.g., capable of continuous operation at temperatures of 375° F. (191° C.) or higher), such as PEEK, PAEK, PPS, PES, PPSU, LCP, and/or PAI, that can be coated with additional compatible thermoplastic material, and that coating could include chopped fiber or other reinforcement and then the material could be top coated with a nonstick surface.
[0063] Also, for additional dimensional strength, a non-woven, woven, or unidirectional fabric consisting of a reinforcement material capable of withstanding the operating temperatures of 375° F. (191° C.) or higher continuously could be laminated to the thermoplastic woven material before or during the additional coating passes mentioned above.
[0064] The composites of embodiments of this invention desirably have or include a rigid molded shape, and are insulative in nature (i.e., does not want to conduct heat), durable, nonstick, low friction, cleanable, chemical resistant, corrosion resistant, heat resistant, and/or capable of bleeding heat quickly. Also, desirably, the substrate weave is capable of conforming to shapes during a compression or thermoforming process such that it will not tear, wrinkle, or fold. The composite material and forming of this invention is useful in cookware and cooking appliance components such as, without limitation, bakeware, microwave applications, and oven cooking (convention, conveyor, rapid cook, brick/stone, accelerated cooking, etc.). The composite material and forming of this invention is useful in other consumer or industrial goods/applications, and/or automotive applications such as, without limitation, providing corrosion and/or chemical resistance or thermal resistance or insulation to parts, such as tubing, fluid containers, oil pans, and/or exhaust parts. These properties also make the material useful in forming aerospace and/or defense parts.
[0065] Exemplary cookware pressed or molded from the laminate material include cooking sheets or trays, such as shown in
[0066] Cookware of this invention further includes cooking components, such as appliance components, preferably, but without limitation, oven, fryer, or toaster components.
[0067] Thus the invention provides a laminate composite material that is formable by heated press or other stamp/press molding. By this invention, the nonstick coating can be applied prior to forming, thereby providing an efficient forming process, and allowing for storing and transfer of the material prior to pressing, stamping or otherwise molding.
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[0069] Various and alternative sizes, shapes, materials, and configurations are available for the support frame of this invention. For example, the support frame can be round, rectangular, or any suitable shape. Support frame length, width and/or height can vary depending on need. In one embodiment of this invention, the length and/or width is about 4 inches to 20 inches, more desirably about 12 inches to 15 inches, and preferably between about 13 inches to about 14 inches. For example, the food support or substrate can be 4, 6, 12, 13, 14, 15, or 16 inches square, or rectangular, such as 6 inches by 12 inches. Also, the open spaces between the cross bars can promote cooking, but can be replaced with a full or partial solid floor. Alternative crossbar patterns are also within the scope of the invention, depending on need.
[0070] The support frame 120 includes an inner support structure for receiving and supporting/holding removable cooking inserts, desirably spaced above the crossbars 130. In the embodiment of
[0071] A plurality of the support bars 140 are placed in and spaced as need across the support frame to receive and support cooking inserts.
[0072] The cooking inserts of this invention are removable for washing and/or to substitute other inserts. The inserts provide for a food cooking system that allows for cooking of various food shapes, sizes, and/or types, with one base frame and, for example, separately purchasable inserts.
[0073] As shown in
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[0075] As shown in
[0076] The support frame 120 of, for example,
[0077] The support frame 120 can receive and secure a substrate insert 165 which sits on the crossbars 130 to form a food support. The substrate is semi-rigid or flexible, such as thermoformed fluoropolymer sheets or film inserts of PPS or PPS and fiberglass, and the support frame 120 provides the desired rigidity for holding food while being placed in and out of an oven. The support frame can be used to provide a more pleasing appearance, allows for easy cleaning and replacement of used substrates, as needed, and/or provides rapid heat dissipation, which can be beneficial for proper cooking and improves operator safety. Rapid heat dissipation is particularly desirable in embodiments of this invention, so as to not add to the cooking time over conventional cooking sheets or baskets.
[0078] Material blends such as PPS/PAI/PTFE, PPS/PAI/PFA/PTFE, LCP/PTFE, LCP/PTFE/PFA, or solid PTFE, PFA, FEP, PPS or LCP alone, can provide non-stick, stain resistant, and/or other easy cleaning or heat dissipative properties. The support frame and substrate are desirably both formed from a high temperature or heat resistant material that is also resistant to steam and water, thereby providing durability for multiple heating and cleaning cycles. The support frame, inserts, and substrates are desirably formed of one or more polymers having a low thermal conductivity and/or microwave transparency, thereby maximizing the cooking energy applied to the food. Additives can be included to promote desirable properties.
[0079] Exemplary additives include materials that reduce the thermal mass and enable rapid cooling, such as hollow glass spheres, chopped fiberglass, mica, etc.
[0080] The substrate for placement within the support frame 120 can be solid as shown in
[0081] The mesh substrate 165 includes a plurality of openings having a length and/or width of about 0.10 inch (about 0.381 cm) to about 0.65 inch (about 1.27 cm), desirably about 0.2 inch (about 0.508 cm) to about 0.3 inch (about 0.762 cm), and more desirably about 0.22 inch (about 0.559 cm) to about 0.28 inch (about 0.711 cm). The openings have a generally square shape, although alternative shapes, such as rectangular, circular or irregular shapes, can also be used. As will be appreciated, forming the mesh of yarns or threads can result in, for example, less than perfectly square-shaped openings. Therefore, in one embodiment of this invention, the lengths and widths across the plurality of openings vary by a small margin, but at least some point include the measurements described above.
[0082] Thus, the invention provides a food support, particularly a cooking basket, tray, pan, or sheet, useful for placing and removing food items from, and holding food items while in, an oven. The food support of this invention is high temperature resistant, and can be used in ovens having retention heat temperatures as high as 600° F. (about 316° C.). The variable inserts provide the ability to cook different food items and provide desirably browning and heating characteristics. The support frame allows for use of the inserts and/or substrates in a rigid, durable, and visually pleasing manner.
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[0084] As an alternative to the cooking inserts of
[0085] The tray of
[0086] The system of
[0087] The support frame and cooking/surface inserts are all desirably formed from a high temperature or heat resistant material that is also resistant to steam and water, thereby providing durability for multiple heating and cleaning cycles. The support frame and inserts are desirably formed of one or more polymers having a low theiinal conductivity and/or microwave transparency, thereby maximizing the cooking energy applied to the food. Material blends such as PEEK/PTFE (or other fluoropolymers/blends), PAEK/PTFE, PPS/PAI/PTFE, PPS/PAI/PFA/PTFE, LCP/PTFE, LCP/PTFE/PFA, or solid PTFE, PFA, FEP, PPS or LCP alone, can provide non-stick, stain resistant, and/or other easy cleaning or heat dissipative properties. In preferred embodiments, the surface inserts is formed of pure melt-processible fluoropolymers, such as discussed above. Additives can be included to promote desirable properties. Exemplary additives include materials that reduce the thermal mass and enable rapid cooling, such as hollow glass spheres, chopped fiberglass, mica, etc.
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[0091] In embodiments of this invention, the cooking inserts 300 are formed, at least in part, of a disposable or single use material made from natural or pulp materials, such as bagasse, wheat straw, paper, wood, hemp, bamboo, etc. These inserts are capable of withstanding single cook cycles and thus are considered highly relevant for certain uses. For example, the cooking inserts 150 of
[0092] In some embodiments of this invention, the single-use pulp cooking inserts are pre-packaged and sealed prior to cooking, typically at a remote location and shipped to the restaurant for cooking.
[0093] Thus, the invention provides cooking devices or components, such as a cooking basket, tray, or sheet, useful for placing and removing food items from, and holding food items while in, an oven, and materials therefor. The cookware and materials of this invention are nonstick and high temperature resistant, and can be used in ovens having retention heat temperatures as high as 600° F. (about 316° C.). The variable cooking inserts provide the ability to cook different food items and provide desirably browning and heating characteristics. The support frame allows for use of the inserts and/or substrates in a rigid, durable, and visually pleasing manner. The surface inserts allow for improved and replaceable/recyclable nonstick surfaces.
[0094] It will be appreciated that details of the foregoing embodiments, given for purposes of illustration, are not to be construed as limiting the scope of this invention. Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention, which is defined in the following claims and all equivalents thereto. Further, it is recognized that many embodiments may be conceived that do not achieve all of the advantages of some embodiments, particularly of the preferred embodiments, yet the absence of a particular advantage shall not be construed to necessarily mean that such an embodiment is outside the scope of the present invention.