Nonstick composite and molded nonstick cookware
A laminated composite material with heat-resistant polymers addresses the durability and stability issues of polymer-coated cooking utensils, enhancing their performance in high-temperature cooking environments by providing structural rigidity and burn prevention.
Patent Information
- Application Number
- JP2021555543
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Priority Date
- 2019-08-20
- Filing Date
- 2020-04-15
- Publication Date
- 2025-02-05
- Estimated Expiration
- 2040-04-15
AI Technical Summary
Existing polymer-coated cooking utensils suffer from issues such as polymer flaking off, lack of durability, and insufficient stability during high-temperature cooking, particularly in high-speed ovens, leading to food support and cleaning challenges.
A laminated composite material comprising multiple layers of flexible substrates coated with heat-resistant polymers, such as PTFE, is used to create cooking utensils with enhanced structural rigidity and burn prevention, applied through methods like dip coating or spray coating, ensuring stability and ease of handling during high-temperature cooking.
The laminated composite material provides improved durability, heat resistance, and burn prevention, allowing for efficient cooking in high-temperature environments while maintaining ease of use and cleaning, suitable for both consumer and industrial applications.
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Abstract
Description
[Technical field]
[0001] The present invention relates to cookware, specifically to heat-resistant polymeric materials and product applications including non-stick polymeric cooking surfaces, materials, composites and coatings. [Background technology]
[0002] Related Technology Details Nonstick cookware, including but not limited to pots, pans, baking sheets, cake / bread pans, etc., have been popular for commercial and residential use for many years. Typical and common cookware includes metal cookware coated with a fluoropolymer, such as polytetrafluoroethylene (PTFE). Over time, the polymer coating tends to flake off the metal or otherwise become less effective due to residue buildup. Residential users tend to replace the entire cookware, while commercial / industrial users often send the cookware out for re-coating. There is a continuing need for improved nonstick cookware and cookware that does not contain metals that retain heat and cause uneven cooking after removal from the oven.
[0003] Polymer-coated non-metallic cooking sheets and baskets are known for heating food products and toasting sandwiches in ovens. Such temperature-resistant sheets or baskets are particularly useful for quickly toasting sandwiches in high-speed or rapid-cook ovens, such as those from TurboChef Technologies, Inc. (Carrollton, Texas) and / or Welbilt, Inc. (United Kingdom). High-speed ovens typically incorporate multiple cooking elements, such as those selected from hot air, infrared, radiant, conductive, steam, and / or microwave.
[0004] Known polymer-coated cooking sheets and / or cooking baskets / trays are useful for baking or cooking food, but often lack the desired food support, durability, cleanliness, heat dissipation (for proper cooking and / or worker safety), and / or commercial restaurant appearance, especially when the food is cooked in front of the customer. Also, these known sheets and baskets are typically removed from the oven with a pizza paddle or the like, which typically does not provide sufficient desired stability for the removed sheet or basket. U.S. Patent No. 8,857,652, incorporated herein by reference, discloses a cooking support to remedy these problems. There is also a continuing need for improved cooking utensils and materials for flexible cooking of a variety of foods in high temperature / high speed ovens. Summary of the Invention
[0005] An overall object of the present invention is to provide improved non-stick materials and products, e.g., pans, baskets, trays, sheets, bakeware and accessories (e.g., lids, covers, oven shelves, baking trays), particularly cookware used in fast cook, rapid cook, and / or conventional ovens. Embodiments of the inventive utensils facilitate placement in and removal from the oven, provide structure to hold and support food, cool quickly, do not retain heat (e.g., are largely or completely metal-free), and can withstand temperatures in excess of 375°F (191°C), more preferably 500°F (260°C), for an indefinite period of time.
[0006] Another general object of the present invention is to provide a non-stick reusable cookware / bakeware that includes at least one polymeric cooking surface. The cooking surface can be molded from a "non-stick" polymer, can include a non-stick additive as part of the polymer matrix, can be dip or spray coated with a non-stick polymer, and / or can be covered with a removable non-stick polymeric surface insert. A variety of polymers are available for these applications.
[0007] Embodiments of the present invention provide an improved fabric / plastic / non-stick laminate that can be pressed or otherwise molded in a fabrication process to provide a formed cookware or other non-stick item / component, where pressing provides structural benefits.
[0008] The present invention includes a method of forming a nonstick component, the method comprising the steps of providing at least two laminate layers, each of which includes a flexible substrate, and pressing the at least two laminates together under heat and pressure to form a cookware. At least two, and desirably at least three, laminates are typically aligned over one another for pressing. The individual laminate layers can have the same or different materials, sizes, shapes, and / or configurations, as desired.
[0009] In an embodiment of the invention, the pressing step desirably creates a raised edge for improved construction and / or as required for use of the component. One or more of the laminates can be edge layers, which further extend around the peripheral edge of the laminate when the laminate alone creates a central support surface. In a three laminate layer composite, each of the first and second laminates of the laminate layer can be edge layers, which extend around the peripheral edge of the third laminate of the laminate for edge support and / or form the central support surface of the third laminate alone. In some embodiments, the second laminate is pressed between the first and third laminates. In one example, the third laminate includes airflow openings and is pressed between the solid first and second laminates.
[0010] The present invention further comprises: At least two laminate layers pressed or molded together under heat and pressure in a forming device A non-stick apparatus comprising pressed laminates having structural rigidity, where each laminate layer individually comprises a flexible substrate coated with a non-stick coating. The apparatus optionally includes a peripheral raised edge, e.g., a first laminate of the laminate layers includes an edge layer that extends around a peripheral edge of a second laminate of the laminate and / or creates a central support surface for only the second laminate.
[0011] In one embodiment, the apparatus includes three separate laminate layers pressed together. As an example, each of the first and second laminates of the laminate layers is an edge layer, where the edge layer extends around the peripheral edge of the third laminate of the laminate and forms a support surface for only the third laminate. The third laminate can be pressed onto or between the first or second laminate.
[0012] In an embodiment of the invention, the flexible substrate is impregnated with a heat resistant polymeric material such as fluoropolymers (e.g., PTFE, FEP, PFA, MFA®, ETFE), fluoroelastomers, silicone rubbers, silicone resins, urethane rubbers, urethane resins, polyketones, polyether ether ketones (PEEK), polyamide imides (PAI), polyphenylene sulfide (PPS), polyphenylene sulfones (PPSU), liquid crystal polyesters (LCP), polyether sulfones (PES), epoxies, quartz, fluorinated materials such as fluorinated mica, combinations thereof, and other non-stick, easily cleaned materials. The flexible substrate may be a polymeric material such as fiberglass, Kevlar, (Registered Trademark) , Nomex (Registered Trademark) , carbon fiber, quartz fiber, PEEK, PAEK, PPS, PES, PPSU, LCP, and / or PAI fibers, or combinations of such fibers or yarns, woven substrates, nonwoven substrates, open mesh / leno weave substrates, braided substrates, and / or unidirectional fabrics. The non-stick coating is desirably coated at least over a polymeric material, preferably PTFE or other non-stick material.
[0013] In an embodiment of the invention, the apparatus includes a cookware for holding food items during cooking including a food support surface including a non-stick coated cooking surface, the cookware being pressed or molded into the shape of a basket, tray, sheet, pan, bowl or cup, plate, cover or other cookware accessory, and each of the cookware and food support surface being completely free of metal.
[0014] The invention further relates to a composite material comprising a flexible substrate impregnated with a heat resistant polymeric material, the composite material having structural rigidity when cured, the composite material being pressable or moldable into a predetermined shape prior to curing, and upon curing retaining the predetermined shape with structural rigidity, the predetermined shape being for example a consumer product, preferably a cookware item, or a machine component.
[0015] Exemplary polymers for laminate embodiments of the present invention include synthetic resins. Synthetic resins and thermoplastics are currently used in textiles and conveyor belts. These are typically resins mixed with fluoropolymers and / or silicones. The incorporation of synthetic resins and silicones generally precludes structural use, so synthetic resins are used for wear and tear rather than structure. The material composite of the present invention can incorporate 100% synthetic resins until the woven glass substrate is fully saturated, and when molded, the synthetic resins interlock into the structural components. Another feature is that the present invention bonds non-stick materials such as fluoropolymers and silicones to the 100% synthetic resins. This provides good bond strength.
[0016] The present invention provides a composite material comprising a flexible substrate impregnated with a heat resistant polymeric material and coated with a non-stick coating, which when cured, has structural rigidity. The composite material can be pressed or molded in one or more layers into a predetermined shape before or during curing, and upon curing, retains the predetermined shape with structural rigidity. The predetermined shape is a consumer product, preferably a cookware item, or a machine component (e.g., a vehicle).
[0017] Embodiments of the invention include surface coatings such as spray or dip coatings, as well as applied as films or coated fibers. In additional embodiments of the invention, the cooking surface is first dip or spray coated and then covered / laminated with one or more cast or laminated films, or coated fibers, such as, for example: silicone materials and / or fluoropolymers, such as melt processable fluoropolymers or blends of PTFE and melt processable fluoropolymers. Spray coatings and cast films, etc., desirably interlock with each other during curing, providing a stronger bond with the underlying cookware surface.
[0018] The present invention further provides a woven / plastic / non-stick laminate material with structural advantages that is pressable or otherwise moldable in a forming process to provide a molded cookware or other non-stick item / component. The material composite of the present invention can incorporate flexible and / or fibrous materials that are 100% impregnated with synthetic resins, which when molded can interlock to create a structural component that retains its molded shape.
[0019] Other objects and advantages will become apparent to those skilled in the art from the following detailed description taken in conjunction with the appended claims and drawings. [Brief description of the drawings]
[0020] [Figure 1] FIG. 1 shows a laminate layer according to one embodiment of the present invention. [Diagram 2] FIG. 2 shows a cookware apparatus according to one embodiment of the present invention. [Diagram 3] FIG. 3 shows a cookware apparatus according to one embodiment of the present invention. [Figure 4] FIG. 4 shows a cookware apparatus according to another embodiment of the present invention. [Diagram 5] FIG. 5 shows a cookware apparatus according to another embodiment of the present invention. [Figure 6] FIG. 6 illustrates a pressing method according to one embodiment of the present invention. [Figure 7] FIG. 7 illustrates a pressing method according to one embodiment of the present invention. [Figure 8] FIG. 8 illustrates a pressing method according to one embodiment of the present invention. [Figure 9] FIG. 9 shows a cookware apparatus according to another embodiment of the present invention. [Figure 10] FIG. 10 shows a cookware apparatus according to another embodiment of the present invention. [Figure 11] FIG. 11 illustrates a pressing method according to one embodiment of the present invention. [Figure 12]FIG. 12 illustrates a pressing method according to one embodiment of the present invention. [Figure 13] FIG. 13 illustrates a pressing method according to one embodiment of the present invention. [Figure 14] FIG. 14 illustrates a composite material according to one embodiment of the present invention. [Figure 15] FIG. 15 illustrates a composite material according to one embodiment of the present invention. [Figure 16] FIG. 16 shows the composite layer and building of FIG. [Figure 17] FIG. 17 shows the composite layer and building of FIG. [Figure 18] FIG. 18 illustrates a multi-layer composite material according to one embodiment of the present invention. [Figure 19] FIG. 19 illustrates an exemplary molded cookware according to an embodiment of the present invention. [Figure 20] FIG. 20 illustrates an exemplary molded cookware according to an embodiment of the present invention. [Figure 21] FIG. 21 illustrates an exemplary molded cookware according to an embodiment of the present invention. [Figure 22] FIG. 22 illustrates an exemplary molded cookware according to an embodiment of the present invention. [Diagram 23] FIG. 23 shows a panini press surface according to an embodiment of the present invention. [Figure 24] FIG. 24 illustrates a cookware component, preferably molded as a cooking appliance component, according to an embodiment of the present invention. [Diagram 25] FIG. 25 illustrates a cookware component, preferably molded as a cooking appliance component, according to an embodiment of the present invention. [Figure 26] FIG. 26 illustrates a cookware component, preferably molded as a cooking appliance component, according to an embodiment of the present invention. [Figure 27] FIG. 27 illustrates a cookware component, preferably molded as a cooking appliance component, according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] The present invention further provides an improved woven / non-stick laminate material that has structural advantages and is pressable or otherwise moldable in forming processes to form fabricated cookware or other non-stick items / components.
[0022] The present invention provides products thereof including heat-resistant and / or non-stick materials and cookware comprising at least one non-stick polymeric cooking surface. As used herein, cookware includes, but is not limited to, various pots, pans, sheets and baskets, bakeware such as cake / bread pans and cooking sheets, and cookware / equipment components. The cookware includes a non-stick cooking surface formed of or covered or coated with a polymeric material. Suitable polymeric materials include, but are not limited to, silicone and fluoropolymer materials.
[0023] The present invention includes improved heat resistant materials and products for use in, particularly, fast cooking and / or high temperature conventional ovens, such as vehicle components and cooking appliances. In some preferred embodiments, the products are made entirely of polymeric materials and are substantially or completely free of metals, and thus non-metallic. As noted above, any suitable high heat resistant polymer may be used. "Non-metallic" means that the entire formed product and / or each layer or element is free of metals.
[0024] An embodiment of the present invention includes a pressable laminate material that includes a flexible substrate coated with a non-stick material. Desirably, the pressed material includes two or more layers of laminate material, or two different laminate materials pressed together. Pressing the planar laminate layers under high heat and pressure into a non-planar shape provides a structure with sufficient structural rigidity for use (e.g., a cookware shape, etc.). The materials used, the number of laminate layers, and the intended configuration and shape all contribute to the structural rigidity and strength of the resulting non-stick device. A desired number of layers, e.g., three, desirably more than three, e.g., four or five, more desirably more than eight, and preferably at least ten in some embodiments, are laminated with or without a non-stick coating (e.g., by replacing the laminate coating of the intermediate layer with another heat-resistant polymer), and then optionally covered with a non-stick fluoropolymer film or coated fabric, etc., on one or both sides of the heavy laminate product.
[0025] 1 shows a laminate material (20) for a laminate layer of an embodiment of the present invention. The laminate material includes a flexible substrate (22) coated with a heat resistant polymer (24), preferably one that provides a non-stick surface to the coated substrate. Exemplary flexible substrates include fiberglass or other suitable fibrous materials, such as Kevlar. (Registered Trademark) , Nomex (Registered Trademark) , carbon fiber, quartz fiber, PEEK, PAEK, PPS, PES, PPSU, LCP, and / or PAI fibers, or combinations of such fibers or yarns.
[0026] 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. Heat resistant polymers can include fluoropolymers (e.g., PTFE, FEP, PFA, MFA®, ETFE), fluoroelastomers, silicone rubbers, silicone resins, urethane rubbers, urethane resins, polyketones, polyether ether ketones (PEEK), polyamide-imides (PAI), polyphenylene sulfide (PPS), polyphenylsulfone (PPSU), liquid crystal polyesters (LCP), polyether sulfones (PES), epoxies, quartz, fluorinated materials such as fluorinated mica, combinations thereof, and / or other non-stick, easy-to-clean materials.
[0027] In an embodiment of the invention, the polymer (24) is or provides a non-stick coating, such as the materials disclosed herein, applied over the substrate (22), or any central layer. The non-stick coating (24) is desirably easily cleaned, chemically resistant, abrasion resistant, and stain resistant. Exemplary non-stick materials include fluoropolymers, silicone rubbers, and resins. Once formed, the composite desirably can withstand temperatures of over 375°F (191°C) continuously, up to 800°F (426°C), depending on the synthetic resin utilized. The polymer (24) and / or non-stick coating can be applied onto the substrate (22), for example, by dip coating, spray coating, curtain coating, or powder coating. The non-stick surface can alternatively be applied by casting, extruding, skiving, or laminating PTFE-coated fibers onto the surface of any intermediate polymeric material. The non-stick coating can be applied prior to forming the pressed article, as described further below, or after forming the pressed article.
[0028] In an embodiment of the invention, a microwave absorbing material or coating may be applied prior to application of the coating polymer (24) or as a component of the coating polymer / non-stick surface application, which may be applied as a coating or laminate material in a manner similar to that described above.
[0029] The composite materials of the present invention are useful for forming press molded articles such as consumer goods and cookware. According to some embodiments of the present invention, the molding process begins with a substrate such as a woven fiberglass substrate that may include coated linear strands. The substrate may optionally be saturated 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 use at high temperatures. Multiple passes of the coating may be used to sufficiently saturate the fibers and build the appropriate weight for flow and moldability. The plastic coated substrate is preferably dried and prepared into a prepreg (pre-impregnated) state, similar to the application of epoxy resin to fiberglass used in printed circuit boards.
[0030] A protective coating of PTFE or other non-stick material is applied to one or both sides. A fluoropolymer coating provides a release function during molding and a high performance release finish during cooking (similar to a pan coating). Coatings can be applied, for example, by monolayer coating with a heavy coating and / or multi-ply laminates of lightweight woven or linear glass fibers.
[0031] The uncured, dried composite material can be stored in rolls and fed from the rolls into an automatic molding press for further processing, or it can be fed manually into a press in sheets of different sizes. The molding press typically includes heated platens to which male and female molding dies are attached, with temperatures typically adjusted to above 600°F (315°C). Pressed structures are typically formed at temperatures above the glass transition temperature (Tg) of one or more of the materials. Pressure is also typically adjustable and varies according to size. Testing has shown reasonable results of 30 psi with an air load of 3 tons of total applied pressure. Larger sizes and molds with multiple parts may require significantly more pressure. Matched form molds, or coining, are forms of compression molding that require higher pressures; for the proposed purposes of this invention, 30 to 50 tons of hydraulic pressure are likely to be required.
[0032] After molding, the edges are trimmed off with a die edge such as a steel rule die or punch press. The molded part can be post cured in a batch oven with stepwise temperature cycling to obtain higher operating temperatures and to harden the PTFE and strengthen its bond to the tray. Post molding processing can be used to crosslink, chain extend, or otherwise harden additional included polymeric materials such as artificial resins. The additional polymeric materials can also be post cured to a temperature where they can be fused with the fluoropolymer.
[0033] As will be appreciated, various and alternative post-processing options are available depending on the need and / or end product application. For some parts, a multi-step molding process is used. As an example, some vehicle / aircraft components can be pressed, then heat cleaned (heated / bleached), punched, and pressed a second time before final curing. In another example, to make wires or pegs, laminates of the desired thickness are pressed flat and then cut into prisms, each of which is then machined (drilled, tapped, milled, lathe, cut, etc.), and then finally machined into ends. In some embodiments of the invention, laminates of more than about four layers may need to be pre-pressed flat and then formed by several manipulations and / or machining processes. This can be used to form "taco trays" and / or "wave trays" as shown below. As another example, the laminates can be machined to expose the middle layers, and then the exposed layers are finally coated.
[0034] In an embodiment of the invention, if the molding process is done at a high enough temperature, the material can be cured during molding. Another option is to post cure with an in-line process such as hot air on a conveyor or an infrared oven. In an embodiment of the invention, molding is done between 600°F (315°C) (and preferably 640°F (338°C)) and 800°F (426°C). At these temperatures, the process can be completed and no post cure is necessary. Higher temperatures can reduce the need for post cure, as the fluoropolymer can be cured simultaneously with molding.
[0035] In an embodiment of the invention, a composite is formed including a woven substrate of high temperature thermoplastic material (e.g., capable of continuous operation at 375°F (191°C) or higher), such as PEEK, PAEK, PPS, PES, PPSU, LCP, and / or PAI, which can be coated with an additional compatible thermoplastic material, which coating can include short fibers or other reinforcing materials, and then the material can be coated onto a non-stick surface.
[0036] Also, for additional dimensional strength, a nonwoven, woven, or unidirectional fabric of reinforcing material capable of continuously withstanding service temperatures of 375°F (191°C) or greater can be laminated to the thermoplastic woven material before or during the additional coating passes described above.
[0037] The pressed composites of the present embodiments desirably have or include a rigid molded shape, are inherently insulating (i.e., do not want to conduct heat), durable, non-stick, low friction, cleanable, chemically resistant, corrosion resistant, heat resistant, and / or can dissipate heat quickly. Additionally, desirably, the substrate fabric can conform to shape during the compression or thermoforming process so as not to tear, wrinkle, or fold. The composites and moldings of the present invention are useful for, but are not limited to, bakeware, microwave applications, and cookware and cookware parts for oven cooking (conventional ovens, conveyor ovens, high speed cooking, brick / stone, accelerated cooking ovens, etc.). The composites and moldings of the present invention are useful for other consumer and / or industrial parts / applications, and / or automotive applications, such as tubing, liquid containers, oil pans, and / or exhausts, providing corrosion or heat resistance or insulation to the parts. These properties are also useful for molding the materials into aerospace and / or defense parts.
[0038] FIG. 2 shows a cookware composite (30), i.e., a non-porous (solid surface) cooking sheet or pan. As shown in the exploded view of FIG. 3, the cookware composite (30) is formed by pressing three separate laminate layers (32), (34) and (36). The three laminates (32)-(36) can be the same or different laminate materials. For example, each can be a fluoropolymer-coated flexible substrate to provide a non-stick planar cooking surface (35). Alternatively, for example, the middle laminate layer (34) can optionally be free of non-stick material and can include a different polymeric material to promote adhesion of the layers during pressing. As another alternative, a non-stick coating can be applied separately to the laminate composite during or after pressing.
[0039] Each of the three laminates (32)-(36) began as a flat sheet (FIG. 6). Upon pressing, a cookware shape was formed having a lip (38). The lip (38) extends completely around the peripheral edge and provides an end structure for the cookware to retain food, as well as providing additional structural rigidity to the device. As will be appreciated, various sizes, shapes, materials, and numbers of laminates are available for such devices, as desired.
[0040] Figure 4 illustrates another cookware composite (40) shown in a similar configuration to composite (30) but with a different laminate structure. First, as shown in the exploded view of Figure 5, the first or top laminate layer (42) is solid to provide a planar cooking surface (45), while the second laminate layer (44) and the third laminate layer (46) both have an "edge only" configuration with a central cut-out (47). The laminate layers (44) and (46) are edge layers that provide structural support, particularly in the area of the raised edge (48), while leaving a single layer food contact area (45) to enhance cooking performance by reducing the mass of the sheet / tray apparatus (40).
[0041] Figures 6-8 illustrate a method of forming the composite (40). In Figure 6, three laminate layers (42)-(46) are stacked in planar sheet form. The laminate layers (42)-(46) can be any suitable laminate, such as E-glass and S-glass coated with a fluoropolymer (e.g., PTFE), and are pre-sized / shaped, as needed, such as by cutting or similar techniques. The pre-assembled and stacked laminates are added to a press apparatus (50), shown from different angles in Figures 7 and 8. The upper and lower press plates (52) and (54) have a shape that provides a raised edge (48) during pressing. In an embodiment, the press strength is greater than 1 ton of pressure at a temperature greater than 600°F (about 315°C), desirably greater than 630°F (about 332°C). The part can be die cut to size, for example, via a clicker press and / or pre-fabricated die, after a heated and pressurized lamination process.
[0042] FIG. 9 illustrates another cookware compound (60) shown as a square tray or basket, but further having another laminate structure. As shown in the exploded view of FIG. 10, a middle laminate layer (62) has an open mesh to provide improved airflow for improved cooking. This middle laminate is disposed between upper and lower laminate layers (64) and (66), each having a solid / non-mesh "edges only" configuration, with a central cutout (67). The laminate layers (64) and (66) also provide structural support, especially in the area of the raised edge (68), while leaving a one-layer mesh food contact area (65) for enhanced cooking performance. Additionally, the sandwiched mesh layer improves aesthetics and strategic feel at the raised edge (68).
[0043] Figures 11-13 illustrate the method of forming the composite (60). In Figure 11, three laminate layers (62)-(66) are stacked in planar sheet form. The preassembled and stacked laminates are added to a press apparatus (50), again shown from different angles in Figures 12 and 13. The upper and lower press plates (52) and (54) have a shape that provides a raised edge (68) during pressing.
[0044] In an embodiment of the invention, one or more of the individual laminate layer composites of the invention can incorporate 100% synthetic resin. The synthetic resin can be applied to a flexible substrate until the substrate is sufficiently saturated such that when molded, the synthetic resin will interlock to create the structural component. The invention further provides for an outer layer of fluoropolymer or silicone to be bonded to the 100% synthetic resin. This can be easily accomplished and has good bond strength.
[0045] Embodiments of the present invention provide formable composites that are high temperature resistant (≧375° F.). As shown in Figures 14 and 15, composites (80) can be formed by impregnating and / or coating one or more substrates (82) with a plastic material (84), as shown in Figure 16. Exemplary flexible substrates include fiberglass or other suitable fibrous materials, such as Kevlar. (Registered Trademark) , Nomex (Registered Trademark) , carbon fiber, quartz fiber, PEEK, PAEK, PPS, PES, PPSU, LCP, and / or PAI fibers, or combinations of such fibers or yarns. Exemplary plastic materials include engineered thermoplastics and blends thereof, which desirably act as the support and structure of the composite once molded.
[0046] The non-stick coating (86) can be applied over the synthetic resin (84) by, for example, dip coating, spray coating, curtain coating, or powder coating. The surface of the non-stick coating (86) can be applied by casting, extruding, shaving, or laminating a PTFE-coated fabric onto the surface of the synthetic resin. The non-stick coating (86) can be applied prior to forming the molded article, as described below, or after forming the molded article.
[0047] In an embodiment of the invention, a microwave absorbing material or coating (88) may be applied prior to application of the non-stick coating (86) or as a component of a non-stick surface application, as shown in Figure 17. Like the non-stick coating (86) application, this may be applied as a coating or laminate in the same manner as described above.
[0048] Plastic impregnated / coated substrates are available in various and alternative sizes, shapes, and configurations. For example, more than one substrate layer can be impregnated. Additionally, more than one substrate impregnated separately can be laminated together prior to top coating. The multiple layers can be the same or different substrate materials, for example, a coated woven fabric can be laminated to a nonwoven fabric coated on one or both sides. The type and number of layers can be adjusted for stiffness as needed. For example, FIG. 18 shows a laminate structure having 10 layers of resin impregnated substrates, which can provide the desired stiffness for applications such as the oven components of FIGS. 24-27. The desired number of layers, greater than 3 layers, desirably greater than 5 layers, more desirably greater than 8 layers, and preferably at least 10 layers, can be laminated without a nonstick coating and, if desired, covered with a nonstick fluoropolymer film or coated fiber (8) or the like on one or both sides of the heavy laminate.
[0049] Exemplary cookware pressed or molded from any of the laminate materials of the present invention include cooking sheets or trays as described above, breads or cake pans as shown in FIG. 19, and the like. Other exemplary cookware include egg pans or inserts, cups, bowls, cookie sheets, pizza pans, panini press or grill pans, muffin pans, croissant pans, cake pans, pie pans, plates, covers, or other cookware accessories. FIG. 20 is a pressed bread proofing tray or pan that includes multiple proofing wells. FIG. 21 is a pressed taco tray that includes a contoured surface, a V-shape for holding each taco, and although the trays are shown with side walls, they can be formed without side walls or with any side wall configuration. FIG. 22 shows a pressed pizza pan that includes a typical ribbed cooking surface. FIG. 23 shows a panini press surface that includes a contoured or other ribbed surface. A panini press surface can be incorporated into the panini press to provide a non-stick benefit.
[0050] The cookware of the present invention further includes cooking components such as appliance components, preferably including, but not limited to, oven, fryer, or toaster components. Figure 24 shows an oven shelf or other shelf structure. Figure 25 shows a rail or bar that may be used in an oven, but not necessarily in direct contact with food. Using the materials of the present invention to form oven components can provide ovens and the like with easier cleaning due to non-stick surfaces. Figure 26 shows an oven or toaster shelf, and Figure 27 shows a shelf in a representative oven.
[0051] Thus, the present invention can provide a laminate composite material that can be molded by stamping / press molding, such as a heated press. The present invention can provide an efficient molding process, as a non-stick coating can be suitably applied prior to molding, and the material can be stored or transferred prior to molding, such as pressing or stamping.
[0052] The invention illustratively disclosed herein can suitably be practiced in the absence of any element, part, step, component, or ingredient not disclosed herein.
[0053] While the foregoing detailed description has described the invention in connection with certain preferred embodiments thereof, and many details have been set forth for purposes of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments, and that the specific details described in the present invention may be varied considerably without departing from the underlying principles of the invention. What is claimed is any, some, or all of the features of novelty and corresponding systems, components, and other apparatus, and related methods that have been described, suggested, mentioned, exemplified, or indicated herein.
Claims
1. 1. A method of forming a non-stick component, the method comprising: Providing at least two flexible substrate layers; impregnating each of the at least two flexible substrate layers with a heat resistant thermoplastic material; pressing at least two of the impregnated flexible substrate layers together under heat and pressure into a single laminate layer between two shaped press plates to form a cookware; applying a layer of non-stick material to at least one of the impregnated flexible substrate layers during or after pressing; machining the laminate layers in a cutting process to form a non-stick component; said machining exposing an intermediate laminate layer and applying a final non-stick coating to the exposed layer; The method includes:
2. The method of claim 1 further comprising aligning at least two of the flexible substrate layers over one another for pressing.
3. The method of claim 1 , further comprising pressing at least two of the flexible substrate layers together to form a raised edge.
4. 4. The method of claim 3, wherein a first flexible substrate layer of the at least two flexible substrate layers includes an edge layer that extends around a peripheral edge of a second flexible substrate layer of the at least two flexible substrate layers to create a support surface for only the second flexible substrate layer.
5. The method of claim 1 further comprising pressing three separate layers of the flexible substrate together.
6. 6. The method of claim 5, wherein a first flexible substrate layer and a second flexible substrate layer of the three separate flexible substrate layers each include an edge layer, the edge layer extending around a peripheral edge of a third flexible substrate layer of the three separate flexible substrate layers to create a support surface for only the third flexible substrate layer.
7. 6. The method of claim 5, further comprising pressing a second flexible substrate layer of the three separate flexible substrate layers between a first flexible substrate layer and a third flexible substrate layer of the three separate flexible substrate layers.
8. The method of claim 6 , wherein the third flexible substrate layer includes airflow openings, and further comprising pressing the third flexible substrate layer between the first flexible substrate layer and the second flexible substrate layer.
9. said non-stick material comprises a fluoropolymer, preferably a perfluoroalkoxyalkane (PFA), a TFE / perfluoromethylvinylether copolymer (MFA), or a fluorinated ethylene propylene (FEP), a homopolymer or copolymer of PTFE, or a combination of such fluoropolymers; and 10. The method of claim 1, wherein the flexible substrate layer comprises a woven substrate, a nonwoven substrate, an open mesh / leno weave substrate, a braided substrate, and / or a unidirectional fabric formed from fiberglass, Kevlar, Nomex, carbon fiber, quartz fiber, PEEK, PAEK, PPS, PES, PPSU, LCP, and / or PAI fibers, or combinations of such fibers or yarns.
10. 1. A non-stick device comprising a structurally rigid pressed laminate comprising at least two flexible substrate layers pressed together under heat and pressure in a forming apparatus, each of said flexible substrate layers individually includes a flexible substrate layer impregnated with a heat resistant thermoplastic material and a laminate coated with a non-stick coating and at least pressed thereon; It further includes a raised rim around the perimeter; a first flexible substrate layer of the at least two flexible substrate layers includes an edge layer, the edge layer extending around a peripheral edge of a second flexible substrate layer of the at least two flexible substrate layers to create a support surface for only the second flexible substrate layer; Device.
11. 11. The non-stick apparatus of claim 10 comprising three separate said flexible substrate layers pressed together.
12. 12. The non-stick apparatus of claim 11, wherein a first flexible substrate layer and a third flexible substrate layer of the three separate flexible substrate layers each include an edge layer, the edge layer extending around a peripheral edge of a second flexible substrate layer of the three separate flexible substrate layers and creating a support surface for only the second flexible substrate layer.
13. 13. The non-stick apparatus of claim 12, wherein the second flexible substrate layer is pressed onto or between the first flexible substrate layer or the third flexible substrate layer.
14. 12. The non-stick apparatus of claim 11, wherein the apparatus comprises a cooking utensil for holding food items during cooking that includes a food supporting surface that includes the cooking surface of the non-stick coating.
15. 10. The method of claim 1, wherein the press comprises a pressure of greater than 1 ton and a pressing temperature of greater than 600°F.
16. The method of claim 1 , wherein the machining comprises punching the laminate layer or cutting an opening in the laminate layer.
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