Physical non-stick pan with a concave-convex structure and method for producing the same

Abstract

A physical non-stick pan with a concave-convex structure, comprising a pan body (1), characterized in that the inner surface of the pan body (1) forms a uniformly distributed concave-convex structure (11), wherein the concave-convex structure (11) comprises convex ribs (111) projecting from the inner surface of the pan body (1) and a recessed area (112) formed by the enclosing convex ribs (111), wherein a physical non-stick layer is provided at least on the inner surface of the pan body (1) in the recessed area (112), wherein the physical non-stick layer has a rough surface at least micrometer-scale, wherein the rough surface further forms a nanoscale, rough oxide film with a porous structure, wherein the micro- and nanomicroscopically rough film layer has an oil-storing and oil-barrier effect during practical cooking use,which achieves a physical non-stick function.

Description

TECHNICAL FIELD

[0001] The present invention belongs to the field of kitchen appliances and particularly relates to a physical non-stick pan having a concave-convex structure and a method for producing the same. STATE OF THE ART

[0002] Conventional non-stick pans require a chemical non-stick coating to be applied to the inner surface of the pan body. This chemical non-stick coating can decompose at high temperatures and become ineffective, and the coating is quickly destroyed by using a metal spatula. Various solutions already exist on the market to make the non-stick pan have the characteristics of less stickiness, easy cleaning, and fast and even heating. For example, Patent Literature CN201861409U presents a solution in which a plurality of grooves are arranged in a pattern on the surface of the pan bottom, and a Teflon non-stick layer is provided in the grooves. Furthermore, Patent Literature CN103844877A deepens the design of the groove strip adjustment and specifies the length, width, and height of the groove strip, as well as the size and height of the hump.On this basis, the final product is obtained by spraying non-stick paint and then by further processes such as polishing the surface of the pot body.

[0003] Patent literatures CN101396229A, CN107495826A, US10194771B2, CN110448183A, CN1197850A and JP6797109B2 each disclose a physical non-stick pan having a concave-convex structure comprising a pan body.

[0004] The above solutions achieve a certain degree of non-stick effect, but they share the same problem: they both use a chemical non-stick coating. It's well known that the chemical non-stick coating on non-stick pans tends to lose its non-stick effect or easily fall off when frying vegetables at high temperatures. This leads to problems such as food sticking to the pan body and accidental ingestion of chemical coatings.

[0005] Therefore, non-stick pan manufacturers have abandoned the option of applying a chemical non-stick coating to achieve non-stick effects and are striving towards physical non-stick coatings to achieve non-stick effects. Of particular note is the structure of the non-stick coating based on the principle of the lotus leaf effect. The lotus leaf effect, also known as the self-cleaning effect, is mainly applied to the surface of objects to achieve the effect of water and oil repellency. The principle of the lotus leaf effect lies specifically in the fact that the surface of the lotus leaf is covered with a very large number of protrusions with an average size of approximately 53-57 micrometers. These protrusions are also composed of clustered micro-bulges with a size of 6-13 micrometers.The surface of these protrusions is covered with other protrusions of much smaller size, the average size of these protrusions being about 6-8 micrometers, the average height being about 11-13 micrometers, and the average pitch being about 19-21 micrometers. The tips of the protrusions are flattened and slightly concave in the center. Such papillary structures are difficult to see with both the naked eye and an ordinary microscope and are often referred to as multiple nano- and micrometer-scale ultrastructures. These large and small protrusions and bulges on the surface of the lotus leaf are like "hillocks" that bulge out one after the other. The depressions between the "hillocks" are filled with air. This creates an extremely thin, only nanometer-thick layer of air immediately above the leaf surface.The droplets have a minimum diameter of 1-2 mm (1 mm = 1000 µm) and are much larger than the protrusions on the surface of the lotus leaf. Thus, the rainwater falls onto the leaf surface, separated by a very thin layer of air, and can therefore only come into contact with the tips of the "hills" on the leaf surface in a few places, preventing it from penetrating the surface of the lotus leaf. Under their own surface tension, the water droplets form spheres. As they roll, the water spheres attract dust and roll out of the leaf surface, thus creating a cleaning effect on the leaf surface.

[0006] And applying this structure to the surface of a non-stick pan is not far enough to form a physical non-stick layer. The reason is: the lotus leaf is at room temperature, an extremely thin air layer can be formed, and the water droplets falling on the lotus leaf will fall on the leaves even at room temperature or even at low temperatures. But non-stick pans need to be further heated, and the temperature of their pan bodies even rises to more than 250 degrees. Therefore, the application of this structure to non-stick pans is still unable to achieve a complete non-stick effect.

[0007] Therefore, by further optimizing the physical non-stick solution based on the principle of lotus leaf effect, it is possible to make a non-stick pan physically non-stick by more effectively considering the characteristics of the environment in which the non-stick pan is used.

[0008] The physical non-stick technology on the pan surface alone is not sufficient for a long-lasting non-stick effect, as the spatula must be rubbed over the pan surface several times during each use. The physical non-stick layer is then worn away by prolonged friction, and the lasting non-stick effect cannot be achieved. Therefore, this problem also needs to be urgently addressed. CONTENT OF THE PRESENT INVENTION

[0009] The object of the present invention is to provide a pan with a long-lasting non-stick effect by protecting the physical non-stick layer from destruction.

[0010] To achieve this, the main technical solution of the present invention is to provide a physical non-stick pan with a concave-convex structure comprising a pan body, characterized in that the pan body forms a uniformly distributed concave-convex structure on the inner surface of the pan body, the concave-convex structure comprising convex ribs protruding from the inner surface of the pan body and a depressed region formed by enclosing the convex ribs, the physical non-stick layer being provided at least on the inner surface of the pan body in the depressed region.Since this solution provides a physical non-stick layer at least on the inner surface of the pan body in the recessed area, and the convex rib has a height difference from the recessed area, the spatula can only touch the surface of the convex ribs during repeated scraping. The physical non-stick layer in the recessed area is protected by convex ribs, preventing wear of the physical non-stick layer. This contributes to a long-lasting non-stick effect. This physical non-stick layer incorporates the surface structure based on the lotus leaf effect principle mentioned in the prior art.

[0011] In the main technical solution of the present invention, the physical non-stick layer comprises a rough surface at least micrometer-sized, wherein the rough surface further forms a rough nanoscale oxide film with a porous structure. Micrometer- and nanomicroscopic rough film layers exhibit oil storage and oil barrier effects during practical cooking use, thereby achieving a physical non-stick function. The pore size of the oxide film is capable of expanding or shrinking in response to changes in heating temperature. After the consumer heats and maintains the pan with pork or animal fat or oil during use, the pore size of the oxide film increases with increasing temperature and shrinks with decreasing temperature. Furthermore, it should be noted that when the user heats the pan body, the opening of the oxide film expands, facilitating the entry and exit of the fat.When the heating of the pan body is stopped, the temperature of the pan body gradually cools down, the opening of the oxide film contracts, and the grease entering the opening is trapped in it, thereby realizing the oil barrier function.

[0012] In some embodiments, the recessed area also includes a physical non-stick layer on the sidewall of the convex ribs. The addition of this structure provides a non-stick effect beneath the concave-convex structure; if it is not provided, sticking to the sidewall may occur. The shortcomings of the existing physical non-stick principle in the heated state are described in the prior art. This solution is based on the physical non-stick effect of the lotus leaf, combined with the oil- and water-repellent effect to achieve the physical non-stick effect in the truest sense.

[0013] In some embodiments, it is provided that the rough surface comprises a plurality of at least micrometer-scale protrusions, wherein at least micrometer-scale should be interpreted as micrometer- or nanometer-scale.

[0014] In some embodiments, the rough surface layer has a hardness of at least HV 400 to 1100. On the one hand, this minimizes wear on the pan body caused by the spatula when using the non-stick pan. On the other hand, it is important to prevent wire balls and other pan-washing tools from abrading the rough surface when brushing the pan body.

[0015] In some embodiments, the recessed area comprises 80% to 95% of the total area of ​​the concave-convex structure, while the convex ribs comprise approximately 5% to 20% of the total area of ​​the concave-convex structure. While the convex rib protects the physical non-stick layer in the recessed area from scooping or abrasion, the surface of the rib is not coated with a non-stick layer. Therefore, it is important to design the percentage of the recessed area relative to the total concave-convex structure. If the convex ribs occupy a large area, this will result in a less effective non-stick pan. If the recessed area occupies a large area, the protection of the convex rib in the recessed area is reduced. In particular, when brushing pans with wire balls, gradual damage to the physical non-stick layer in the recessed area can occur over the years.This part of the assembly ensures that the flange setting protects the physical non-stick layer without compromising the non-stick effect.

[0016] In some embodiments, the recessed area is provided with a recess depth of 0.01 to 0.13 mm. Excessively deep recesses may cause thick foods (e.g., eggs) to stick during frying because the recess is too deep in some areas, resulting in a significant drop in height with food on the convex ribs during food separation. Some food remains in the recessed area and cannot be scooped out.

[0017] In some embodiments, it is provided that the socket body is formed as a single-layer or multi-layer composite structure.

[0018] There is also provided a method for producing a physical non-stick pan having a concave-convex structure, comprising the following steps: S1.1 Concave-convex structure treatment: A uniformly distributed concave-convex structure is created on the surface of a metal sheet by chemical etching or mechanical pressing; S1.2 Stretching process: With the help of equipment, the cup body is manufactured from sheets that form a concave-convex structure; S2 Sandblasting process: Abrasives are selected, and compressed air is used as energy to spray the abrasives onto the surface of the cup body, so that the surface of the cup body forms a rough surface at least micrometer-scale, wherein the S3 surface treatment further comprises: hardening and oxidation treatment are carried out on the surface of the cup body to further form a nanoscale, rough oxide film with a porous structure on the rough surface, wherein the micro- and nanomicroscopically rough film layer has an oil-storing and oil-blocking effect during practical cooking use, thereby achieving a physical non-stick function.

[0019] In some embodiments, the S2 sandblasting process includes: 36~130 mesh abrasives are selected, and 0.4~0.8MPa compressed air is used as energy to spray the abrasives onto the surface of the cup body through the high-speed sprayer, so that the surface of the cup body forms a rough surface composed of multiple protrusions of at least micrometer size.

[0020] In some embodiments, it is provided that the S3 surface treatment further comprises: S3.1 Hardening process: The heat treatment of the cup body is carried out to achieve a surface hardness of HV400 to 1100; S3.2 Oxidation process: The oxidation process is carried out on the cup body that has reached the hardening standard, and a nanoscale rough oxide film with a porous structure is further formed on the rough surface of the cup body.

[0021] In some embodiments, the S3.1 hardening process includes: Before performing the heat treatment, the pan body is cleaned and then placed in a heat treatment furnace. The heat treatment lasts for 0.5 to 24 hours in an environment of 400 to 650 degrees Celsius, resulting in the formation of a hardening layer with a hardness of HV400 to 1100 and a thickness of 3 to 35 micrometers on the surface of the pan body.

[0022] In some embodiments, it is provided that the S3.2 oxidation process comprises: The pan body with the formed hardening layer is placed in a treatment furnace with liquid or gas and oxidized in an environment of 400~650 degrees Celsius for 0.5 to 2 hours.

[0023] In some embodiments, it is provided, further comprising S4 polishing process: The predetermined region of the inner surface of the pan body is mechanically polished to remove the rough surface on the convex ribs in the concave-convex structure and to retain the rough surface on the depressed region in the concave-convex structure, thereby obtaining a pan body of the non-stick pan.

[0024] The advantageous effects of the present invention are: 1. A concave-convex structure is provided, the convex rib protection is arranged on the non-stick layer in the depressed area, which reduces the direct friction between spatula and non-stick coating and prolongs the non-stick effect of the pan body. 2. The lotus leaf imitation surface structure, in combination with the environment in which the non-stick pan is located, can produce the effects of tiny air storage and hydrophobicity on the microscopically rough oxide film. 3. When maintaining the non-stick pan, the oxide film of the non-stick pan can achieve the function of oil barrier, and the inner surface of the pan body still has the lotus leaf-like waterproof hydrophobicity and physical non-stick function after maintaining the pan, even if it is washed with a neutral detergent. 4. The omission of the chemical non-stick coating makes the non-stick pan healthier and more hygienic to use. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic structural view according to an embodiment of the present invention; Fig. 2 is a schematic structural view of the concave-convex structure according to the embodiment of Fig. 1 in combination with a rough surface; Fig. 3 is a schematic structural view of the nanoscale roughness on the protrusions according to the embodiment of Fig. 1; Fig. 4 is a schematic representation of the socket body according to the embodiment as a multi-layer structure. List of reference symbols: 1 pan body 11 Concave-convex structure 111 convex ribs 112 deepened area 12 working shifts 13 heat-conducting intermediate layer 14 outer heat-absorbing layer 2 projections a nanoscale roughness DETAILED DESCRIPTION

[0025] The technical solutions in embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in embodiments of the present invention. Of course, the described embodiments are only a part of the embodiments of the invention, but not all. Starting from the embodiments of the present invention, all other embodiments that one of ordinary skill in the art will fall within the scope of the present invention.It will be understood by those of ordinary skill in the art that in the disclosure of the present invention, the terms "longitudinal," "transverse," "top," "bottom," "front," "back," "left," "right," "vertical," "horizontal," "tips," "bottom," "inside," "outside," and the like refer to orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings and are used only to facilitate and simplify the description of the invention and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed, and function in a particular orientation, and therefore the above terms are not to be construed as limiting the present invention.

[0026] It should be understood that the term "one" is to be understood as "at least one" or "one or more," i.e., in one embodiment, the number of elements may be one. In alternative embodiments, the number of such elements may be multiple, and the term "one" is not to be understood as a limitation on the number. Example I.

[0027] With reference to Fig. 1 to 4 of the accompanying drawings of the description of the present invention, a physical non-stick pan with a concave-convex structure according to a preferred embodiment of the present invention is shown. Types of non-stick pans include cooking pans, frying pans, woks, milk pans, etc. The present embodiment is illustrated by a wok pan whose non-stick pan comprises a pan body 1. The pan body 1 can be single-layer or multi-layer. In the single-layer pan body 1, the pan body 1 can be made of iron or stainless steel. The alloying elements in this stainless steel are Cr, Ni, Ti, Mn, N, Nb, Mo, Si, Cu, and other elements, with the main alloying element being Cr. Fig. 1 and Fig. 2, the pan body 1 is, for example, single-layered and comprises an inner working layer 12. In the multi-layered pan body 1, the pan body 1 can be made of iron or stainless steel or a composite material. But regardless of whether the pan body 1 is single-layered or multi-layered, at least the inner surface of the pan body 1 is made of iron or stainless steel. As in Fig.3, the pan body 1 is, for example, multi-layered and comprises, from the inside out, a working inner layer 12, a heat-conducting intermediate layer 13, and a heat-absorbing outer layer 14. Thus, at least the surface material of the working inner layer 12 is made of iron or stainless steel. Furthermore, the surface material of the pan 1 must not be made of aluminum. The pan body 1 has a physical non-stick layer on the inner surface, wherein the physical non-stick layer has a rough surface at least on a micrometer scale, wherein at least a micrometer scale is interpreted as a micrometer scale or a nanometer scale.The rough surface further forms a nanoscale rough oxide film with a porous structure. The micro- and nanomicroscopic rough film layer has an oil storage and oil barrier effect during actual cooking use, thereby achieving a physical non-stick function. It should be noted that the nanoscale roughness of oxide film formation is mainly generated by the oxide particles generated by the oxidation process, such as oxides (iron oxide) in iron pans, oxide films (the main component is chromium trioxide, etc.) in stainless steel. The pore size of the oxide film may shrink in response to changes in heat temperature because the oxide film is generated from the base metal, bonded to the base metal as a unit, and firmly bonded to the base. In addition, the oxide film has excellent heat resistance.

[0028] In particular, the rough surface comprises a plurality of micrometer-scale protrusions 2, wherein the rough surface has a surface layer with a hardness of at least HV 400 to 1100, the inner surface of the pan body 1 forms a uniformly distributed concave-convex structure 11, wherein the concave-convex structure 11 comprises convex ribs 111 projecting from the inner surface of the pan body and a recessed area 112 formed by the enclosing convex ribs 111, wherein the physical anti-adhesion layer is provided at least on the inner surface of the pan body in the recessed area 112. The recessed area 112 is also provided with a physical anti-adhesion layer on the sidewalls of the convex ribs 111, which increases the effect of this structure in ensuring the anti-adhesion effect under a concave-convex structure, without which sidewall adhesion may occur.The convex ribs 111 are provided in the recessed area 112 to protect the physical non-stick layer on the inner surface of the pan body 1. Without the convex ribs 111, the spatula would repeatedly rub directly against the physical non-stick layer during frying. If used in this manner for a long time, the rough surface will wear down and no longer have any non-stick effect. The area of ​​the recessed area 112 accounts for 80 to 95% of the area of ​​the entire concave-convex structure 11, the area of ​​the convex ribs 111 accounts for 5 to 20% of the area of ​​the entire concave-convex structure 11, and the recessed area 112 has a recess depth of 0.01 to 0.13 mm. In the present embodiment, the preferred recess depth is 0.05 to 0.06 mm. If the depth of the depression is too great, thick foodstuffs (e.g.Eggs) may stick during frying because the recess is too deep in some areas, creating a large drop in height with food on the convex ribs while separating the food. Some food remains in the recessed area and cannot be scooped out. In summary, with this solution, since the physical non-stick layer is present at least on the inner surface of the pan body in the recessed area and the convex rib has a drop in height with the recessed area, the repeated scraping of the spatula can only be done on the surface of the convex ribs. In turn, the non-stick coating in the recessed area is protected from the wear of the physical non-stick layer by the use of convex ribs, thus achieving a long-lasting non-stick effect.

[0029] When the user heats and maintains the pan with pork fat or animal fat or oil during the first use, the pore size of the oxide film expands as the temperature of the pan body rises and contracts as the temperature of the pan body 1 drops. Furthermore, it should be noted that when the user heats the pan body 1, the opening of the oxide film expands, facilitating the entry and exit of the grease. When the heating of the pan body 1 is stopped, the temperature of the pan body 1 gradually cools, the opening of the oxide film contracts, and the grease entering the opening is trapped therein, thereby realizing the oil barrier function. The deficiencies of the existing physical non-stick principle in the heated state are described in the prior art.This solution is based on the physical non-stick effect of the lotus leaf, combined with the oil and water repellent effect to achieve the physical non-stick effect in the truest sense.

[0030] It is particularly worth noting that the current experiments found that the above structure was used: Iron and stainless steel pans are capable of locking the above-mentioned oil. However, this was not possible with aluminum pans because they were hard-anodized to create micrometer- and nano-rough surfaces, which, however, exhibit poor non-stick performance. Thus, non-stick performance can only be achieved through coating. Example II

[0031] A process for producing a non-stick pan as described in Example I is set forth, comprising the following steps: S1 Manufacturing of the cup body 1: Use of plates for the manufacture of the cup body 1; S2 Sandblasting process: Abrasives are selected, and compressed air is used as energy to spray the abrasives onto the surface of the cup body 1 so that the surface of the cup body 1 forms a rough surface of at least a micrometer scale; S3 Surface treatment: Hardening and oxidation treatment are carried out on the surface of the cup body to further form a nanoscale rough oxide film with a porous structure on the rough surface. S4 Polishing process: The predetermined portion of the inner surface of the pan body 1 is mechanically polished to remove the rough surface on the convex ribs 111 in the concave-convex structure 11 and to retain the rough surface on the depressed portion 112 in the concave-convex structure, thereby obtaining a pan body of the non-stick pan; since the surface of the convex ribs is not provided with a non-stick layer, it is determined that this part of the arrangement ensures that the provision of the convex ribs can protect the physical non-stick layer and does not impair the effect of the non-stick pan. S5 Cleaning and packaging process: The polishing wax from the pan body 1 is removed using ultrasonic cleaning, then the pan body is cleaned with deionized hot water, a handle is riveted to the pan body, and finally the pan is packaged as a finished product.

[0032] In particular, S1 production of the socket body 1 further comprises: S1.1 Treatment of the concave-convex structure 11: A uniformly distributed concave-convex structure is formed on the surface of an iron or stainless steel sheet by chemical etching or mechanical pressing, with the depression depth being 0.01 to 0.13 mm, with the preferred depression depth being 0.05 to 0.06 mm. If the depression is too deep, food may remain in the depression 112 during frying and cannot be scooped out. The cross section of the convex ribs 111 of the concave-convex structure 11 can be semicircular or rectangular. The concave-convex structure 11 is formed on the surface of an iron or stainless steel sheet by chemical etching, engraving, or rolling. Engraving includes die engraving and laser engraving, with mechanical pressing being widely used, and laser engraving enables the production of more precise patterns.By chemical etching or mechanical pressing, the convex ribs 111 occupy 5 to 20% of the area of ​​the entire concave-convex structure 11, and the area of ​​the recessed portion 112 accounts for 80 to 95% of the area of ​​the entire concave-convex structure 11. The above two area ratio ranges represent only the situations arising from the present embodiment. Generally speaking, it is only necessary to minimize the occupancy area of ​​the convex ribs 111 and increase the occupancy area of ​​the recessed portion 112. Using a metal spatula during cooking does not destroy the hard physical non-stick layer in the bulges, so the pan can achieve a lasting non-stick effect. S1.2 Stretching process: the iron sheet or stainless steel sheet forming the concave-convex structure 11 is stretched using a stretching machine to manufacture the pan body 1, and the edge of the pan body is rounded and smooth, and the thickness of the pan body 1 is 0.3 to 8 mm, and preferably the thickness of the pan body 1 is 0.6 to 5 mm.

[0033] In the present embodiment, S2 sandblasting process includes: 36~130 mesh abrasives are selected, and 0.4~0.8MPa compressed air is used as energy to spray the abrasives onto the surface of the cup body by the high-speed spraying device (e.g., a spray gun, etc.), so that impurities are completely removed from its inner surface and the surface of the cup body forms a rough surface composed of a plurality of protrusions of at least micrometers, wherein the abrasives are brown corundum or white corundum, etc.

[0034] In the present embodiment, S3 the surface treatment further comprises: S3.1 Hardening Process: After sandblasting, the ladle body 1 is cleaned, and the cleaned ladle body 1 is placed in a gas- or liquid-filled heat treatment furnace. The heat treatment lasts for 0.5 to 24 hours in an environment of 400 to 650 degrees Celsius, resulting in the formation of a hardening layer with a hardness of HV400 to 1100 and a thickness of 3 to 35 micrometers on the surface of the ladle body. S3.2 Oxidation process: The oxidation process is performed on the ladle body 1 that has reached the hardening standard, that is, the ladle body 1 that has formed a hardening layer is placed in a treatment furnace with liquid or gas and oxidized at 400 to 500 degrees Celsius for 0.5 to 2 hours, and a nanoscale rough oxide film with a porous structure is further formed on the rough surface of the ladle body 1.

[0035] It should also be noted that the two steps of hardening and oxidation can be carried out in the same treatment furnace, or the two steps can be carried out separately.

[0036] Furthermore, after the completion of the hardening and oxidation processes, observation through a microscope reveals that the surface of the cup body 1 forms a micrometer-scale rough surface with a thickness of 3-35 micrometers and a hardness of HV400 to 1100 on the inner surface of the cup body. A nanoscale rough oxide film with a porous structure further forms on the rough surface, transforming the surface structure into a physical non-stick layer with non-stick properties. At this time, a rough surface and a nanoscale rough oxide film with a porous structure also exist on the surface of the convex ribs 111.

[0037] In the present embodiment, to remove the rough surface on the convex ribs 111, step S4 of the polishing process in the method for manufacturing the non-stick pan is specifically as follows: In order not to damage the micro-nano structure of the inner surface of the pan body, the inner surface of the pan body is polished with a soft cloth wheel, thus polishing off the rough surface from the convex ribs 111, so that the surface of the convex ribs 111 becomes relatively smooth; and the outer surface of the pan body is polished with a nylon wheel with 60 to 320 meshes, which can effectively prevent the pan body 1 from slipping on the gas stove. overview

[0038] From the above-mentioned Example I and Example II, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: The pan body 1 is colored dark gray or black after hardening and oxidation by heat treatment; these colors are preferred by the average consumer. However, when used with normal metal-based cookware, it tends to stick, so the present application further provides a physical non-stick layer with a hardened micrometer or nanoscale, rough surface on the inner surface of the cup body. After the consumer heats and maintains the pan with pork or animal fat or oil for the first use, the temperature of the pan body 1 rises and the pore size of its nanoscale, rough oxide film increases with temperature. Pork fat or animal fat or oil penetrates through the hole. When the heating of the pan body 1 is stopped, the temperature of the pan body 1 gradually cools down, and the pore size of its nanoscale, rough oxide film shrinks with the temperature, thereby enclosing the fat, which in turn acts as an oil barrier. The next time the pan body 1 needs to be heated for frying, the fat goes in and out again, and the micro- or The nanostructured rough surface combines with the oil-blocking effect to prevent sticking to the pan and achieve a physical non-stick effect. The inner surface of the well-maintained pan body still maintains a hydrophobic and physical non-stick function, similar to the non-stick function of a lotus leaf, even when cleaned with a neutral detergent. The present invention is based on the bionic principle of the lotus leaf effect,and then, in combination with the characteristics of the usage environment of the pan body 1, is designed in such a way that the pan achieves a non-stick effect without spraying chemical coatings by forming a micrometer- or nanoscale rough structure on the inner surface of the pan body 1 combined with the formation of the oxide film having an oil barrier function and a nanoscale rough structure on the rough surface. Furthermore, the long-standing opinion in this industry that the bottom of the pan body should be as smooth as possible to achieve unpredictable non-stick effects has changed.The present invention effectively solves the problem that this industry has long relied on chemical coatings to improve the non-stick effect, but cannot solve the problem of non-stick failure or easy peeling when frying vegetables at high temperatures, thereby making people's diets healthier.It should be particularly noted that, in addition to the inventive proposal of the present invention to achieve a non-stick effect without the need to spray chemical coatings by forming a submillimeter-, micrometer- and / or nanoscale multi-layered rough structure on the inner surface of the pan body 1 based on the bionic principle of non-stick lotus leaves, the combination of process parameters for the sandblasting, heat treatment and oxidation processes mentioned in the present invention is an important factor in ensuring the best non-stick effect, and the combination of the process parameters is also one of the inventive ideas of the present invention.The formation of micro- and nanometer-scale rough surfaces and hardened layers on the surface requires strict control of the process parameters for blasting, heat treatment, and other processes to achieve the desired non-stick properties. The process parameters proposed in the present invention were developed by the inventor after extensive experimentation and repeated corrections and cannot be derived by the average person skilled in the art through imagination or simple deduction. To achieve the best results, it is also necessary to use the combination of process parameters of the present invention.

[0039] The present invention is not limited to the best modes described above, and various other forms may be derived from each under the inspiration of the present invention. However, regardless of changes in form or structure, any technical solution having the same or similar form as the present application falls within the scope of the present invention.

Claims

[1] Physical non-stick pan with a concave-convex structure, comprising a pan body (1), characterized byin that the inner surface of the pan body (1) forms a uniformly distributed concave-convex structure (11), wherein the concave-convex structure (11) comprises convex ribs (111) protruding from the inner surface of the pan body (1) and a depressed region (112) formed by the enclosing convex ribs (111), wherein a physical non-stick layer is provided at least on the inner surface of the pan body (1) in the depressed region (112), wherein the physical non-stick layer has a rough surface at least on the order of a micrometer, wherein the rough surface further forms a nano-scale, rough oxide film with a porous structure, wherein the micro- and nanomicroscopically rough film layer has an oil-storing and oil-barrier effect during practical cooking use, thereby achieving a physical non-stick function. [2] Physical non-stick pan with a concave-convex structure (11) according to claim 1, characterized by that the side walls of the convex ribs (111) are also provided with a physical non-stick layer. [3] Physical non-stick pan with a concave-convex structure (11) according to claim 1, characterized by that the rough surface comprises several projections (2) of at least micrometer scale. [4] Physical non-stick pan with a concave-convex structure (11) according to claim 1, characterized by that the rough surface has a surface layer with a hardness of at least HV 400 to 1100. [5] Physical non-stick pan with a concave-convex structure (11) according to claim 1, characterized by that the recessed area (112) accounts for 80% to 95% of the total area of ​​the concave-convex structure (11), while the convex ribs (111) account for about 5% to 20% of the total area of ​​the concave-convex structure (11). [6] Physical non-stick pan with a concave-convex structure (11) according to claim 1, characterized bythat the recessed area (112) has a recess depth of 0.01 to 0.13 mm. [7] Physical non-stick pan with a concave-convex structure (11) according to claim 1, characterized by that the socket body (1) is designed as a single-layer or multi-layer composite structure. [8] A method for producing a physical non-stick pan with a concave-convex structure (11), comprising the following steps: S1.1 Concave-convex structure treatment: by chemical etching or mechanical pressing, a uniformly distributed concave-convex structure (11) is produced on the surface of a metal sheet; S1.2 Stretching process: using equipment, the cup body (1) is manufactured from sheets forming a concave-convex structure (11); S2 Sandblasting process: Abrasives are selected, and compressed air is used as energy to spray the abrasives onto the surface of the cup body (1) so that the surface of the cup body (1) forms a rough surface at least micrometer-scale, wherein the method further comprises S3 surface treatment: hardening and oxidation treatment are carried out on the surface of the pan body (1) to further form a nanoscale, rough oxide film with a porous structure on the rough surface, wherein the micro- and nanomicroscopically rough film layer has an oil-storing and oil-blocking effect during practical cooking use, thereby achieving a physical non-stick function. [9] A method for producing a physical non-stick pan with a concave-convex structure (11) according to claim 10, characterized by that the S2 sandblasting process includes: 36~130 mesh abrasives are selected, and 0.4~0.8MPa compressed air is used as energy to spray the abrasives onto the surface of the cup body (1) through the high-speed sprayer, so that the surface of the cup body (1) forms a rough surface composed of a plurality of protrusions (2) of at least a micrometer size. [10] A method for producing a physical non-stick pan with a concave-convex structure (11) according to claim 9, characterized by that the S3 surface treatment also includes: S3.1 Hardening process: the heat treatment of the pan body (1) is carried out to achieve a surface hardness of HV400 to 1100; S3.2 Oxidation process: the oxidation process is carried out on the cup body (1) which has reached the hardening standard, and a nanoscale rough oxide film with a porous structure is further formed on the rough surface of the cup body (1). [11] A method for producing a physical non-stick pan with a concave-convex structure (11) according to claim 10, characterized by that the S3.1 hardening process includes: before carrying out the heat treatment, the pan body (1) is cleaned and then placed in a heat treatment furnace, during which the heat treatment lasts for 0.5 to 24 hours in an environment of 400 ~ 650 degrees Celsius, which leads to the formation of a hardening layer with a hardness of HV400 to 1100 and a thickness of 3 to 35 micrometers on the surface of the pan body. [12] A method for producing a physical non-stick pan with a concave-convex structure (11) according to claim 10, characterized by that the S3.2 oxidation process includes: the pan body (1) with the formed hardening layer is placed in a treatment furnace with liquid or gas and oxidized in an environment of 400~650 degrees Celsius for 0.5 to 2 hours. [13] A method for producing a physical non-stick pan with a concave-convex structure (11) according to claim 8, characterized by , further comprising S4 polishing process: the predetermined portion of the inner surface of the pan body (1) is mechanically polished to remove the rough surface on the convex ribs (111) in the concave-convex structure (11) and to keep the rough surface on the depressed portion (112) in the concave-convex structure (11), thereby obtaining a pan body (1) of the non-stick pan.

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