A method for treating the surface of the working surface of a cooking utensil, and a cooking utensil for cooking food.

Abstract

The present invention relates to a method for treating the surface of a working surface of a cooking utensil used for preparing food. The method according to the present invention comprises the following steps: structuring the working surface with a laser processing device, in which case the working surface is structured by at least one laser beam, the at least one laser beam having a pulse width of at least 500 ns or less, and the structuring forming a profile having at least one recess; applying a lubricant to the structured working surface; and heat-treating the structured working surface with the lubricant at a temperature of 50°C to 700°C. A cooking utensil according to the present invention has a working surface treated according to the method according to the present invention.

Description

Technical Field

[0001] The present invention relates to a method for treating the surface of the working surface of a cooking appliance for cooking food, and a cooking appliance for cooking food.

[0002] From the prior art, cooking appliances such as stainless steel pots for boiling food, for example, are known, and the working surface of the stainless steel pot is smoothly formed by polishing performed in the manufacturing process. After long-term use, the working surface becomes uneven due to scratches and dirt, and as a result, food residues remain attached to the working surface of the stainless steel pot, making it difficult to clean.

[0003] From the prior art, a plurality of embodiments for improving the non-stick property of cooking appliances are known. In Patent Document 1, for this purpose, a roughened working surface is disclosed, on which a ceramic material such as an alumina-titania powder mixture is thermally sprayed. In Patent Document 2, it is proposed to coat the working surface with diamond crystals in order to obtain a hard and thermally conductive coating. Furthermore, it is also known to form a coating containing perfluoroalkyl compounds and polyfluoroalkyl compounds, also called so-called PFAS (per- and polyfluoroalkyl substances), on the working surface. These components do improve the non-stick property of the working surface, but are extremely harmful to health and the environment.

[0004] In known cooking appliances according to the prior art, due to a relatively macro manufacturing method for forming a plurality of recesses on the working surface, the dimensional distribution of these recesses is hardly controlled. The dimensions of these recesses vary statistically greatly and fluctuate significantly. Furthermore, the coatings of the known working surfaces are neither persistent nor durable. In many cases, when the usage period of a known cooking appliance becomes long, the non-stick coating and / or the working surface of the cooking appliance itself peel off or wear, and as a result, the non-stick property of the known cooking appliance is greatly impaired after long-term use.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] European Patent Application Publication No. 0365458 [Patent Document 2] European Patent Application Publication No. 1048751 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Therefore, the object of the present invention is to develop a method for treating the surface of the working surface of a cooking utensil and a corresponding cooking utensil, in particular to improve the non-stick properties of the cooking utensil, for a longer service life, and while reducing the environmental impact. [Means for solving the problem]

[0007] The problem of the present invention is solved by a method having the features of claim 1. This method is a method for treating the surface of the working surface of a cooking utensil for preparing food ingredients, The steps include supplying cooking utensils into the laser processing device, The laser processing device is used to structure the working surface of a cooking utensil. (In this case, the laser processing device structures the working surface with at least one laser beam, the laser beam having a pulse width of at least 500 ns or less temporarily, and this structuring forms a profile on the working surface having at least one recess.) The steps include applying a lubricant to the structured working surface, The process involves heat-treating a structured working surface containing a lubricant at a temperature of 50°C to 700°C while holding the treated working surface, A method that includes this.

[0008] The problems of the present invention are further solved by a cooking utensil having the features of claim 13, which defines a cooking utensil having a working surface for cooking food, the working surface of which is treated by the method of the present invention.

[0009] By structuring the working surface of the cooking utensil according to the present invention with at least one laser beam within a laser processing apparatus, it is ensured that at least one recess, in particular all of the formed recesses, are formed to the same dimensions within manufacturing tolerances. Thus, the formation of at least one recess in the profile is reproducible, in particular with respect to multiple recesses in the same profile, and / or with respect to multiple cooking utensils that are successively structured according to the present invention.

[0010] For example, structuring of a working surface can be performed by simply a single laser beam, which is also known as "direct laser drawing." For the purpose of structuring a working surface, the laser beam can be focused on the processing location on the working surface to increase energy density and power density. In structuring a working surface, the laser beam can be configured to move relative to the working surface, which is also known as "scanning." This can be performed, for example, by a laser scanner, a mirror scanner which can be configured as a Garbo scanner and / or a polygon scanner. The laser scanner is configured to deflect at least one laser beam in one or two dimensions. Furthermore, in another embodiment of the present invention, the working surface of a cookware can be moved translationally relative to at least one, particularly spatially fixed, laser beam, which can be done, for example, by at least one servo motor. In a particularly advantageous development of the present invention, at least one laser beam and the cookware are movable in one or two dimensions, which enables particularly high-speed structuring of the working surface.

[0011] To improve process efficiency, the working surface can also be structured using at least two laser beams, as described above in "direct laser drawing." In a further development of this feature, multiple laser sources connected in parallel to each other can be used in the laser processing apparatus to generate at least two laser beams for structuring the working surface. The number of laser beams should preferably match the number of laser sources in the laser processing apparatus. In another embodiment, the laser processing apparatus has one laser source, and its beam (also called the "seed beam") is split into at least two partial beams. This is done, for example, by a diffractive optical element. The multiple partial beams thus obtained based on the original laser beam of the laser source can be used to structure the working surface, in which case at least one of these partial beams, in particular multiple partial beams, can be focused separately from each other. At least two laser beams of the laser processing apparatus can be given a specific spatial relationship to each other, especially when using the aforementioned diffractive optical element.

[0012] The temporal pulse width of at least one laser beam can be set to a maximum of 15 ps. This ensures that the thermal effects during profile generation are suppressed as much as possible, thereby improving the manufacturing quality of the recesses. Furthermore, melting and thermally-induced material damage, particularly stress cracking, are prevented. It is known that the shorter the pulse width, the more negligible the thermal effects become, resulting in a more mechanically processed working surface of the cookware. This effect is also called cold abrasion. From this perspective, the temporal pulse width of the laser beam can be set to a maximum of 10 ps, ​​which further reduces the thermal effects. In addition, the precision of structuring is improved.

[0013] For similar reasons, the temporal pulse width of the laser emission can be set to a maximum of 1 ps, thereby obtaining even better surface quality on the work surface. Preferably, a temporal pulse width of 100 fs to 15 ps, and especially 100 fs to 1 ps, is set.

[0014] Furthermore, the output power of the laser radiation can be 1W to 5kW, particularly 1W to 500W, and / or the energy of the laser pulse can be 10μJ to 200mJ, particularly 10μJ to 100mJ. At least one laser beam can have a beam diameter of 2μm to 6μm when structuring the working surface, particularly in the working surface region. In generating the structure according to the present invention, 2 to 1000 single pulses can be superimposed within a single spatial region, and as a result, a high structural aspect ratio can be obtained with the corresponding high material removal amount.

[0015] Furthermore, two precisely interfering laser beams can be used to structure the working surface of a cooking utensil using a laser processing device. In an advanced form of the present invention, three interfering laser beams can be used, which enables the structuring of a working surface, for example, in which multiple recesses are arranged in a hexagonal pattern. In this case, the structured part has three axes along the working surface, and multiple recesses are arranged along these axes with one lateral period. In the hexagonal pattern of the present invention, the lateral periods of the three axes are all the same. Furthermore, four interfering laser beams can be used to form a quadrilateral pattern of multiple recesses when structuring the working surface. Furthermore, nine interfering laser beams can be used.

[0016] This structuring of the working surface expands the working surface by forming at least one recess, improving the wettability of the surface by the lubricant. According to the applicant's findings, on the working surface structured by the present invention, the lubricant is "drawn" into the recess by capillary forces generated in the microstructure regions and stored there at least temporarily. This improves non-stick properties compared to known cookware.

[0017] Another fundamental idea of ​​the present invention is that polymerization, as well as oxidation and hydrolysis, can be carried out by heat treatment of the lubricant introduced to the work surface structured according to the present invention. As a result, the reaction products are stored in at least one recess of the work surface profile and adhere very well to the work surface due to the aforementioned surface area expansion. Consequently, the applied lubricant forms a lubricating film, also known as a "tribofilm." Due to the structuring of the work surface performed according to the present invention, these properties are particularly long-lasting, protecting the topography of the work surface from mechanical wear for as long as possible. Thus, the present invention provides environmentally friendly and durable cookware that maintains stable non-stick properties even after prolonged use. In addition, since the method according to the present invention does not require an additional cleaning step, cookware surface-treated according to the present invention is ready to use immediately after the completion of the method.

[0018] Preferably, the structuring of the working surface of the cookware is performed by a laser processing device using the interference of at least two laser beams. By using at least two laser beams that interfere with each other to structure the working surface, a large area of ​​the working surface can be processed in a relatively short time, and as a result, the process efficiency of surface structuring in the method according to the present invention is also improved. In particular, the working surface of the cookware can be surface-structured over the entire surface on a micrometer and / or nanometer scale in a short processing time, which results in significantly higher process efficiency and lower manufacturing costs compared to other known processing methods.

[0019] In this invention, cooking utensils include all utensils for cooking food, such as utensils for frying (Braten), boiling (Kochen), grilling (Grillen), baking (Backen), roasting (Roesten), and simmering (Schmoren). Working surface refers to the surface of a cooking utensil that comes into contact with the food being cooked, i.e., the ingredients, during the cooking process. In this invention, cooking includes, on the one hand, wet cooking techniques that use drinking water to cook ingredients, such as boiling or steaming, and on the other hand, dry cooking techniques that do not add drinking water to cook ingredients, such as frying, baking, or grilling.

[0020] Preferably, at least one laser beam, in particular at least two laser beams that interfere with each other, have a pulse width of at least 1 ns to 20 ns, thereby increasing the processing speed of structuring the working surface. Using a pulse width of 1 ns to 20 ns enables structuring of the working surface with a higher depth of field, that is, it allows for greater flexibility in the depth direction when structuring the working surface.

[0021] Preferably, the dimensions of at least one recess in the working surface are formed such that the depth relative to the unstructured portion of the working surface is 10 nm to 50 μm, particularly 100 nm to 15 μm, or 1 μm to 25 μm. In other embodiments of the present invention, the dimensions of the recess may coincide with the length in the x and / or y directions. In this case, if there are multiple recesses in the present invention, the y direction corresponds to the offset direction of the recess, and the x direction is perpendicular thereto. The x and y directions are each perpendicular to the normal to the working surface, i.e., they extend along the working surface, respectively. In the present invention, the dimensions may also indicate direction as a combination of the x and y directions, which generally corresponds to the transverse direction.

[0022] In another embodiment of the present invention, at least two recesses are formed with substantially the same dimensions, particularly with substantially the same depth. In the present invention, when two dimensions are substantially the same, it means that the difference between them does not exceed the processing tolerances generally occurring in the same kind of method. At least two adjacent recesses can be arranged at an interval of 10 nm to 50 μm, particularly 100 nm to 15 μm, or 1 μm to 25 μm. With such a structured working surface, a structural shape on the order of 10 nm to 50 μm, particularly 100 nm to 15 μm, or 1 μm to 25 μm can be realized on the cooking utensil at an industrially suitable processing speed while ensuring reproducibility.

[0023] Preferably, on the working surface, at least one group of recesses is formed in a certain periodic pattern. This is because this structuring can be formed very easily, particularly by using a plurality of laser beams that interfere with each other. In the context of the present invention, this period refers to the distance between two identical structural features of different recesses of the periodic pattern, that is, for example, the starting point of the first recess of the periodic pattern and the starting point of the recess adjacent to this and of the same periodic pattern. Instead of or in addition to this, in the present invention, the period may also refer to the distance between the center point of the first recess of the periodic pattern and the center point of the recess adjacent to this and of the same periodic pattern. Since these recesses of the periodic pattern are arranged offset in the lateral direction, in the present invention, it is also called the lateral period, which, as described above, refers to the distance between the repeated structural features of these adjacent recesses of the periodic pattern.

[0024] Preferably, this group of recesses in the periodic pattern on the working surface is formed with a lateral period of 10 nm to 50 μm, particularly 100 nm to 15 μm, or 1 μm to 25 μm, in at least one direction along the working surface. By periodically structuring the working surface with a lateral period of such an order, it becomes possible to form the advantageous surface functions required for the cooking appliance described at the beginning. This group of recesses in this periodic pattern may further have different periods for each of a plurality of directions when three, four, or more interfering laser beams that interfere with each other are used to structure the working surface. In an advantageous development, this group of recesses has the same period in two different directions in its periodic pattern. Furthermore, it is possible for this group of recesses to have the same period in three different directions in its periodic pattern, which corresponds, for example, to a hexagonal arrangement of a plurality of recesses. This group of recesses is formed, for example, as a sinusoidal linear structure in which a plurality of recesses and a plurality of ridges are alternately arranged with the same lateral period respectively.

[0025] In another embodiment of the present invention, at least one group of recesses can also be formed on the working surface of the cooking appliance in a linear shape, and / or in a basic shape of a rectangle (preferably a square), and / or in a basic shape of a circle. The basic shapes of these recesses can be polygonal, particularly hexagonal. As a special case, these recesses can be formed as a plurality of straight lines, and these straight lines can be shifted particularly perpendicularly to their extending direction and / or arranged with a defined lateral period.

[0026] Preferably, these recesses, particularly this group of recesses, have a lateral spread of 10 nm to 49 μm, particularly 10 nm to 10 μm, or 1 μm to 25 μm, in a direction parallel to the direction of their lateral period, whereby particularly advantageous non-sticking properties of the cooking appliance are obtained. Particularly preferably, all the recesses each have a lateral spread of about 10 nm to 49 μm, particularly 10 nm to 10 μm, or 1 μm to 25 μm.

[0027] Preferably, these recesses, and in particular this group of recesses, have an aspect ratio of 0.01 to 5, and more particularly 0.01 to 1. In the present invention, the aspect ratio is the ratio of the depth of the recess (17) to the lateral spread of the recess (17).

[0028] Preferably, to improve the efficiency of this method, the structuring of the working surface is performed in a single work step.

[0029] In an advanced form of the present invention, at least two groups of first recesses, particularly the first group of recesses, can be formed with a first transverse period of 10 nm to 50 μm, particularly 100 nm to 15 μm or 1 μm to 25 μm, and at least two second recesses, particularly the second group of recesses, can be formed with a second transverse period, in which case the second transverse period is particularly smaller than the first transverse period. This first transverse period can be 100 nm to 999 μm. However, the second transverse period can be larger than or the same as the first transverse period. The second group of recesses can be constructed in a mathematically similar form to the first group of recesses, so the second group of recesses can be derived from the first group of recesses by mathematical analogous transformations such as translation, rotation, stretching, or scaling. Preferably, the second group of recesses corresponds to the first group of recesses rotated 90° around an axis perpendicular to the tool surface.

[0030] Alternatively, or in addition to the above, at least two first recesses, particularly a first group of recesses, may be formed with a first dimension of 10 nm to 50 μm, in particular 100 nm to 15 μm or 1 μm to 25 μm, and furthermore, at least two second recesses, particularly a second group of recesses, may be formed with a second dimension, in which case the second dimension is smaller than the first dimension. As described above, in the present invention, the dimension of the recess corresponds to its depth.

[0031] Furthermore, in addition to the second set of recesses, at least two third recesses, particularly a third group of recesses, may be formed with a third transverse period and / or third dimension, in which case the third transverse period and / or third dimension is smaller than, in particular, the second transverse period and / or second dimension. In advanced forms, up to 10 groups of recesses can be created, each having its own transverse period and / or dimension, in which case, in particular, the transverse period and / or dimension of each group of recesses is always smaller than the transverse period and / or dimension of the preceding group of recesses.

[0032] Preferably, the regions of multiple second recesses, particularly those of the second group of recesses, at least partially overlap with the regions of multiple first recesses, particularly those of the first group of recesses. The same applies to multiple third recesses, particularly those of the third group of recesses, which may be formed as needed. Such overlaps allow for the combination of structures with different lateral periods and / or dimensions, and especially modulation in a mathematical sense, to impart complex surface structures to the working surface of the cookware that cannot be achieved with simple structuring. As a result, the possibilities for improving the non-stick properties of the cookware are expanded.

[0033] Preferably, the formation of a plurality of first recesses, particularly a first group of recesses, and the formation of a plurality of second recesses, particularly a second group of recesses, is carried out in a single work step or in a plurality of separate work steps. Forming the plurality of first and second recesses in a single work step improves processing speed. In contrast, a configuration in which the plurality of first and second recesses are formed in separate work steps includes, in particular, structuring the working surface with different interference patterns. For example, the cooking utensil can be moved between two successive work steps. Preferably, the cooking utensil can be rotated particularly by 90° between the two steps, thereby making it particularly easy to form the recesses as a cross pattern or a Penrose pattern. The second group of recesses may be positioned perpendicular to the first group of recesses, and as a result, the second transverse period is positioned perpendicular to the first transverse period. Furthermore, the second transverse period may be positioned parallel to the first transverse period, or at an angle between 0° and 180°.

[0034] Preferably, the formation of the second group of recesses is carried out by the polarization of a laser beam selected according to the material of the working surface, thereby forming a laser-induced periodic structure (LIPSS), which can be formed in a single working step, particularly together with the formation of the first group of recesses. The lateral period of the second group of recesses is, for example, less than or equal to the wavelength of the laser beam used. The polarization of the laser beam may be linear, in which case its polarization vector is positioned approximately perpendicular to the direction of extension of the laser-induced periodic surface structure and / or approximately parallel to the lateral period of the laser-induced periodic surface structure. Furthermore, the direction of this polarization vector of the laser beam can be oriented at an angle of 0° to 180° with respect to the lateral period of the first group of recesses, and by oriented the polarization vector of the laser beam in this way, the arrangement of the second group of recesses can be adjusted with respect to the first group of recesses.

[0035] For example, a plurality of first recesses, particularly a first group of recesses, may be formed by the interference of at least two laser beams, in which case a plurality of second recesses, particularly a second group of recesses, may be formed by the interference of at least two laser beams and / or by one laser beam. This means that the first recesses are always formed by laser beams that interfere with each other, but this is not necessarily the case for the second recesses. If the number of second recesses is less than the number of first recesses, or if the area of ​​the second recesses is smaller than the area of ​​the first recesses, it is advantageous to form the second recesses with a single laser beam. Also, if the second recesses are formed by laser beams that interfere with each other, the number of interfering laser beams used may be different from or the same as that used for the first recesses.

[0036] Preferably, at least two groups of recesses are formed in a single periodic pattern, in which case the lateral period of the first group of recesses is positioned at an angle other than 0°, particularly 90°, with respect to the lateral period of the second group of recesses.

[0037] Preferably, the lubricant comprises at least one component from the following group: oil-containing lubricants, oils, food oils, vegetable oils, sunflower oil, rapeseed oil, food-grade chain oils, fats, food-grade fats, vegetable fats, animal fats, synthetic fats, polyalkylene glycols, dry lubricants, food-grade dry lubricants, solid lubricants, carbon-based lubricants, and graphite. In this invention, a food-grade lubricant means a lubricant that conforms to the H1 classification and / or to the Council of Europe Directive EG)EEC93 / 43EWG. In this invention, a lubricant is considered food-grade if there is a possibility of unintentional contact with food and is acceptable to the human body. A food-grade lubricant may contain additives that are harmless to human ingestion and are permitted to migrate to food only in limited amounts.

[0038] In particular, a preferred fat-containing lubricant can be configured to be applied to the structured working surface of a cookware in such a way that the lubricant forms a flat surface, thereby improving the non-stick properties of the cookware.

[0039] Preferably, the heat treatment of the structured working surface described above is performed for at least 1 minute.

[0040] The cooking utensil according to the present invention, in particular its working surface, preferably comprises at least one component from the following group: aluminum, iron, cast iron, stainless steel, carbon steel, especially carbon steel imparted with one magnetic component, ceramic, and fiber-reinforced material.

[0041] Preferably, the cookware has a layer system consisting of at least two layers, in particular the first layer being made of aluminum and the second layer being made of stainless steel, in which case the working surface is in particular the second layer.

[0042] Preferably, the working surface of this cooking utensil has at least one group of recesses, and these recesses have the following dimensions in particular: Transverse period is 100 nm to 50 μm, and / or Lateral dimensions, particularly lateral widths of 10 nm to 49 μm, especially 10 nm to 10 μm or 1 μm to 25 μm, and / or The aspect ratio is 0.01 to 5, especially 0.01 to 1, where the aspect ratio is the ratio of the depth of the recess to the lateral dimension of the recess. It holds.

[0043] Preferably, the lubricant on the working surface has a layer thickness of 10 nm to 500 μm after heat treatment.

[0044] Preferably, this cooking utensil is at least one of the following groups: a stewing utensil (Kochvorrichtung) (for boiling in liquid such as water or soup), a grilling utensil (Grillvorrichtung) (for grilling over an open flame), a deep frying utensil (Bratvorrichtung) (for frying in oil or fat), a baking utensil (Backvorrichtung), or a stewing utensil (Schmorvorrichtung). Preferably, this cooking utensil is one of the following groups: a deep pot (Topf), a roaster (Braeter), an oven plate (Backblech), a frying pan (Pfanne), or a grill rack (Grillrost).

[0045] Further advantages and features will become apparent from the following description, which separately describes the claims and exemplary embodiments of the invention with reference to the drawings. [Brief explanation of the drawing]

[0046] [Figure 1] Schematic diagrams of steps a) to d) of the method according to the present invention related to the cooking utensil according to the present invention. [Figure 2] Schematic diagram of the structured working surface of the cooking utensil according to the present invention [Figure 3] Schematic cross-sectional view of the surface of action shown in Figure 2. [Figure 4] Figure 3 shows the working surface after lubricant has been applied. [Figure 5] Cooking pot with an untreated working surface [Figure 6] A cooking pot according to Figure 5, having a working surface treated according to the present invention. [Figure 7]Baking tray with an untreated working surface [Figure 8] A baking tray in Figure 7 having a working surface treated according to the present invention. [Figure 9] frying pan with an untreated working surface [Figure 10] A frying pan in Figure 9 having a working surface treated according to the present invention. [Figure 11] Grill mesh with an untreated working surface [Figure 12] A grill mesh in Figure 11 having a working surface treated according to the present invention. [Figure 13] A shallow frying pan according to the present invention having a treated working surface according to the present invention [Figure 14] Another shallow frying pan according to the present invention, having a working surface treated according to the present invention [Figure 15] A baking mold according to the present invention having a working surface treated according to the present invention. [Modes for carrying out the invention]

[0047] Figures a) to d) in Figure 1 show a flow diagram of one embodiment of the method according to the present invention for treating the surface of the working surface 10 of a cooking utensil 11, in which the illustrated exemplary embodiment is the working surface 10 of a frying pan (bratpfanne) used to fry food in oil or fat as the object to be cooked.

[0048] In Figure 1(a), the cooking utensil 11 is provided with the working surface 10 in an untreated state. In this state, the working surface 10 is not yet structured 12 and is polished, for example, during the manufacturing process of the cooking utensil 11.

[0049] The provided cooking utensil 11 is sent to a laser processing device 13 schematically shown in Figure 1b) by the method according to the present invention. Using this laser processing device 13, the working surface 10 of the cooking utensil 11 is structured by interference between two laser beams 14 and 15. These laser beams are deflected at a finite angle to each other according to Figure b), and each has a pulse width of approximately 10 ns. That is, these are short pulses that interfere with each other in the region of the working surface 10, thereby enabling the structuring 12 of the working surface 10 of the cooking utensil 11.

[0050] In the exemplary embodiment shown in Figure 1, a single profile 16 is formed having a plurality of linear recesses 17, which are offset from each other and perpendicular to their extending direction. Figure 2 shows a magnified view of the profile 16 of the working surface 10 of the cookware 11 formed by the structure 12. Each of these recesses 17 has a depth of 1 μm, a width of 5 μm, and a substantially sinusoidal cross-sectional shape. This shape is shown in Figure 3, where, for drawing purposes, the y-axis oriented perpendicular to the working surface 10 is drawn on a different scale than the x-axis oriented parallel to the width of the recesses 17. The aspect ratio of the recesses 17, i.e., the ratio of the depth to the width of the recesses 17, is approximately 0.2. These recesses 17 are spaced 5 μm apart perpendicular to their extending direction, resulting in a lateral period l of 5 μm for the working surface profile in the present invention. Figure 3 shows a schematic cross-section of the structured working surface 10 of the cooking utensil 11, from which the sinusoidal shape of the recesses 17 and their lateral period l can be observed in particular.

[0051] This structuring 12 is performed in a single work step over substantially the entire working surface 10 of the cooking utensil 11, and the expansion of the working surface 10 results in surface activation of the working surface 10, and therefore functions as a surface pretreatment in the present invention.

[0052] After the working surface 10 is structured by a laser processing device 13, a fat-containing lubricant 18 is applied to the structured and pre-treated working surface 10, which in this embodiment is edible oil. This lubricant 18 penetrates particularly into the recesses 17 and wets the entire working surface 10 of the cookware 11 as evenly as possible. This lubricant 18 forms a substantially flat layer 19 with a thickness of 100 nm on the cookware 11, and in this invention, this thickness of 100 nm corresponds to the distance from the top 20 of the recess 17 to the surface of the lubricant layer 19.

[0053] This is due, for example, to capillary forces, which are formed in the microstructure regions as a result of the structuring 12 of the working surface 10, drawing the lubricant 18 into these recesses. The lubricant 18 remains attached, at least temporarily. The modified working surface 10 is shown in Figure 1(c). A flat layer 19 of the lubricant 18 is also schematically shown in the cross-section of the working surface 10 in Figure 4.

[0054] Next, as shown in Figure 1, d), the cookware 11 having the lubricant 18 is heat-treated at 250°C for 30 minutes, which in this illustrated embodiment is performed by a heating medium 20 positioned away from the cookware 11, the heating medium 20 schematically shown in Figure 1). In this case, the temperature is selected so that it is lower than the smoke point of the lubricant 18, in this case the cooking oil, but high enough to cause polymerization, oxidation, and hydrolysis of the lubricant 18. The decomposition products of these reactions are deposited in recesses 17, also called microcavities, of the structured working surface 10, and adhere particularly well to the surface expanded by the structure 12, forming a layer 19 or film that reduces friction, this film is also called a "tribo-film". This layer 19, in combination with the structure 12 of the working surface 10, results in improved non-stick properties in the micrometer range and further results in improved corrosion properties of the working surface 10 of the cookware 11 treated according to the present invention.

[0055] Figure 5 shows a cooking pot 21 having an untreated working surface 10, which can be used as both a stewing pot and a roasting pot. In contrast, Figure 6 shows the cooking pot 21 of Figure 5 having a working surface 10 treated according to the present invention, which in particular has a profile 16 with a plurality of recesses 17 and a lubricant 18 applied thereon. Figure 7 shows a baking tray 22 having an untreated surface, and Figure 8 shows a baking tray 22 having a working surface 10 treated according to the present invention, which has a profile 16 with a plurality of recesses 17 and has a lubricant 18 applied to its working surface. Figure 9 shows a frying pan 23 having an untreated working surface 10, and Figure 10 shows a frying pan having a working surface 10 treated according to the present invention.

[0056] Figure 11 shows an untreated grill mesh 24 having a working surface corresponding to at least the upper surface of the grill mesh 24. The grill mesh 24 of Figure 11 is shown in Figure 12, where it has a working surface 10 treated according to the present invention, a portion of which is shown in an enlarged view in Figure 12, and this working surface has a profile 16 having a plurality of recesses 17 and a lubricant 18 as described above.

[0057] Figure 13 shows a photograph of a stainless steel frying pan 23, the majority of which of its working surface 10 is treated according to the present invention, and thus comprises a profile 16 having a plurality of recesses 17 and a lubricant 18. Figure 14 shows a photograph of another frying pan 23, but unlike the frying pan 23 in Figure 13, it is made of carbon steel, also known as carbon steel. The working surface 10 of this frying pan 23 is provided with a profile 16 having a plurality of recesses and a lubricant 18. Figure 15 shows a photograph of a baking mold, the majority of which of its working surface 10 is treated according to the present invention, and comprises a profile 16 having a plurality of recesses and a lubricant 18.

Claims

1. A method for treating the surface of the working surface (10) of a cooking utensil (11) for preparing food ingredients, The steps include providing the cooking utensil (11) into the laser processing device (13), The step of structuring the working surface (10) of the cooking utensil (11) using the laser processing apparatus (13), The laser processing apparatus (13) structures (12) the working surface (10) with at least one laser beam (14, 15), The at least one laser beam (14, 15) has a pulse width of at least 500 ns at a time, A profile (16) having at least one recess (17) is formed on the working surface (10) by the structuring (12). Steps and The steps include applying a lubricant (18) to the structured working surface (10), To obtain the treated working surface (10), the process involves heat-treating the working surface (10) at a temperature of 50°C to 700°C, A method of having.

2. The method according to claim 1, characterized in that the structuring of the working surface (10) of the cooking utensil (11) is performed by the laser processing device (13) using the interference of at least two laser beams (14, 15).

3. The method according to 1 or 2, characterized in that the at least one laser beam (14, 15), in particular the at least two laser beams (14, 15) that interfere with each other, have a pulse width of at least 1 ns to 20 ns temporarily.

4. The method according to any one of claims 1 to 3, characterized in that the dimensions of the at least one recess (17) of the working surface (10) are formed such that the depth of the recess (17) with respect to the unstructured region of the working surface (10) is 10 nm to 50 μm, in particular 100 nm to 15 μm or 1 μm to 25 μm.

5. The method according to any one of claims 1 to 4, characterized in that a group of at least one recess (17) is formed on the working surface (10) in a certain periodic pattern.

6. The method according to 5, characterized in that the group of recesses (17) in the periodic pattern on the working surface (10) is formed to have a transverse period (Δd) of 10 nm to 50 μm, particularly 100 nm to 15 μm or 1 μm to 25 μm, in at least one direction along the working surface (10).

7. The method according to any one of claims 1 to 6, characterized in that a plurality of the recesses (17), particularly the group of recesses (17), have a lateral extent of 10 nm to 49 μm, particularly 10 nm to 10 μm, in a direction parallel to the direction of the lateral periodicity.

8. The method according to any one of claims 1 to 7, characterized in that a plurality of the recesses (17), particularly a group of the recesses (17), have an aspect ratio of 0.01 to 5, wherein the aspect ratio is the ratio of the depth of the recess (17) to the lateral spread of the recess (17).

9. The method according to any one of claims 1 to 8, characterized in that the structuring (12) of the working surface (10) is performed in a single work step.

10. The method according to any one of claims 5 to 9, characterized in that at least two groups of the recesses (17) are each formed in a single periodic pattern, and the lateral period of the first group of recesses (17) is arranged at an angle other than 0°, particularly 90°, with respect to the lateral period of the second group of recesses (17).

11. The method according to any one of claims 1 to 10, characterized in that the lubricant (18) has at least one component from the following group: oil-containing lubricant, oil, edible oil, vegetable oil, sunflower oil, rapeseed oil, food-grade chain oil, fat, food-grade fat, vegetable fat, animal fat, synthetic fat, polyalkylene glycol, dry lubricant, food-grade dry lubricant, solid lubricant, carbon-based lubricant, graphite.

12. The method according to any one of claims 1 to 11, characterized in that the structured (12) working surface (10) is heat-treated for at least one minute.

13. A cooking utensil (11) having a working surface (10) for cooking food ingredients, wherein the working surface (10) is treated according to the method described in any one of claims 1 to 12.

14. The cooking utensil according to claim 13, characterized in that the cooking utensil (11), in particular the working surface (10), has at least one component from the group consisting of aluminum, iron, cast iron, stainless steel, ceramic, fiber-reinforced material, and especially one magnetic component.

15. The cooking utensil (11) has a layer system having at least two layers, wherein the first layer is made of aluminum and the second layer is made of stainless steel, and the working surface (10) is the second layer, as described in 13 or 14.

16. The working surface (10) of the cooking utensil (11) has at least one group of recesses (17), and these recesses (17) have the following dimensions in particular: Transverse period is 100 nm to 50 μm, and / or Lateral dimensions, particularly lateral width, of 10 nm to 49 μm, especially 10 nm to 10 μm or 1 μm to 25 μm, and / or The aspect ratio is 0.01 to 5, particularly 0.01 to 1, where the aspect ratio is the ratio of the depth of the recess (17) to the lateral dimension of the recess (17). A cooking utensil according to any one of claims 13 to 15, characterized by having the following features.

17. The cooking utensil according to any one of claims 13 to 16, characterized in that the lubricant (18) on the working surface (10) has a layer thickness (d) of 10 nm to 500 μm after heat treatment.

18. The cooking appliance (11) is characterized in that it is at least one of the group consisting of a stewing appliance (Kochvorrichtung) (21) (for boiling in liquid such as water or soup), a grilling appliance (Grillvorrichtung) (24) (for grilling over an open flame), a deep frying appliance (Bratvorrichtung) (23) (for deep frying in oil or fat), a baking appliance (Backvorrichtung) (22), and a stewing appliance (Schmorvorrichtung) (21) (for steaming).

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