Surface treatment method for preventing adhesion of adhesive substances to components and components

Abstract

To provide a method for surface-treating a member that does not cause surface peeling or the like and can effectively prevent the adhering of sticky substance such as rice to the member; and a member protected against the adhering of sticky substance to its surface.SOLUTION: The present invention provides a method for surface-treating a member to protect it against the adhering of sticky substance, the method including randomly forming an infinite number of fine irregularities on the surface of the member and flattening the tops of the projections around the recesses. In the invention, the surface of the member may have a skewness 'Rsk' of -1.6 μm<Rsk<-0.3 μm. Out of the recesses in the irregularities on the surface of the member, the recesses with a depth of 2-35 μm may have an entrance width of 25-110 μm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technology for inhibiting adhesion of sticky substances such as rice. [Background technology]

[0002] Regarding the prevention of rice sticking to rice scoops and the like, it is known that unevenness contributes to the prevention of adhesion of adhesive components, as seen in Patent Document 1. Note that "rice" refers to the sticky substance that forms after cooking grains such as rice.

[0003] For example, Patent Document 1 states that a double-embossed surface, which has been subjected to two-stage embossing (a process in which the surface of a mold (casting die or pressing die) is given a fine pattern (unevenness) rather than a mirror finish when molding or pressing metal, resin, etc., and the pattern is then transferred to the molded product), contributes to suppressing adhesion of adhesive components.

[0004] In fact, when observing the surface of a commercially available double-embossed rice paddle, it was confirmed that relatively large protrusions were arranged (aligned at a specified interval) at intervals of approximately 3.55 mm, as shown in Figure 10(A).

[0005] A closer look at the area around the convex portion revealed that the surface was double embossed, with countless small irregularities formed on the surface, as shown in Figure 10(B). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 3634720 Summary of the Invention [Problem to be solved by the invention]

[0007] Patent Document 1 states that the height of the convex portions of the small irregularities is several tens to several hundreds (150 to 300) μm, and does not define the shape of the entrance of the irregularities, such as whether it is a perfect circle, an ellipse, a square, or a triangle.

[0008] Furthermore, although there is no specific description of the method for forming the unevenness, the unevenness formed is described as a "grained surface," and what is called a grained surface is generally a surface that has been grained (physically given a wrinkled pattern). The height (depth) of the grain (wrinkles) is about 30 to 140 μm, and the material is resin.

[0009] However, the rice paddle described in Patent Document 1 has multiple protrusions arranged at intervals of approximately 3.55 mm, as shown in Figure 10(A), so while it can be manufactured relatively easily from resin, it is relatively difficult to manufacture from plate-shaped metal materials. Furthermore, rice grains and the like may adhere to the recesses (bottom) between the protrusions. In such cases, cleaning is troublesome because the surface is not flat, posing hygiene problems. Furthermore, scrubbing the recesses with a scrubbing brush or sponge to remove the rice grains may wear away the embossing that prevents adhesion, making it difficult to maintain the desired effect of preventing rice from adhering over the long term.

[0010] Metal rice paddles and other items are coated with fluorine, and although this fluorine coating also contributes to the prevention of adhesion, there is a concern that the coating layer may peel off and get into food, which could ultimately have an adverse effect on the human body.

[0011] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a surface treatment method that can effectively suppress the adhesion of sticky substances such as rice without causing surface peeling, and a member that has the effect of suppressing the adhesion of sticky substances to its surface. [Means for solving the problem]

[0012] Therefore, the method for surface treatment of a member to inhibit adhesion of adhesive substances according to the present invention includes the steps of: A countless number of minute irregularities are randomly formed on the surface of the member, and the upper surfaces of the protrusions around the recesses are flattened. By setting the skewness "Rsk" of the surface of the component to -1.43≦Rsk≦-0.68, the surface of the component is provided with the effect of suppressing adhesion of sticky substances that form after cooking grains. A surface treatment method for preventing adhesion of adhesive substances to a member, comprising: The depth of the recesses in the uneven surface of the member is in the range of 2 to 35 μm, and the entrance width of the recesses is in the range of 25 to 110 μm. It is characterized by:

[0015] The present invention can also be characterized in that the ratio of the total surface area of ​​the uneven surface to the surface area of ​​the upper surfaces of the projections is 45 to 65%.

[0016] In the present invention, the minute irregularities may be formed by at least one of shot projection treatment, chemical etching, and plasma treatment.

[0017] In the present invention, the upper surfaces of the convex portions may be flattened by polishing, and finishing may be performed after the polishing.

[0018] In the present invention, the finishing process may be a three-dimensional polishing process.

[0019] The member according to the present invention comprises: The surface has a countless number of irregularities randomly arranged, each having a flat upper surface surrounded by a concave portion of the minute concave portion, and By setting the surface skewness (Rsk) to -1.43≦Rsk≦-0.68, the surface is given the effect of suppressing the adhesion of sticky substances that form after cooking grains. A member, The depth of the recesses of the surface irregularities is in the range of 2 to 35 μm, and the entrance width of the recesses is in the range of 25 to 110 μm. It is characterized by:

[0022] The member according to the present invention can be characterized in that the ratio of the total surface area of ​​the uneven surface to the surface area of ​​the upper surfaces of the convex portions is 45 to 65%.

[0023] In the member according to the present invention, the uneven surface may be provided in a portion that comes into contact with an adhesive substance. [Effects of the Invention]

[0026] According to the present invention, it is possible to provide a surface treatment method that can effectively suppress the adhesion of sticky substances such as rice without causing surface peeling, and a component that has the effect of suppressing the adhesion of sticky substances to its surface. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 10 is a diagram showing a summary of the experimental results of samples (1) to (7) according to the present embodiment. [Figure 2] (A) is a magnified image (3D image) of the surface of sample (1), (B) is a magnified image (3D image) of the surface of sample (2), (C) is a magnified image (3D image) of the surface of sample (3), and (D) is a magnified image (3D image) of the surface of sample (4). [Figure 3] (A) is a magnified image (3D image) of the surface of sample (5), (B) is a magnified image (3D image) of the surface of sample (6), and (C) is a magnified image (3D image) of the surface of sample (7). [Figure 4] FIG. 1 is an explanatory diagram of skewness (Rsk). [Figure 5] FIG. 1A is a diagram showing an example of the surface shape and measurement data of sample (7), and FIG. 1B is a diagram showing an example of the surface shape and measurement data of sample (4). [Figure 6] FIG. 1 shows examples of the surface shapes and measurement data of samples (1) to (3). [Figure 7] 10A and 10B are diagrams showing an example of measurement results of width and depth of polishing scratches caused by the polishing process according to the present embodiment. [Figure 8]FIG. 1 is a diagram summarizing the surface skewness (Rsk) values ​​of samples (1) to (7). [Figure 9] FIG. 10 is a diagram showing the results of obtaining the proportion of flat areas on the surfaces of samples (1) to (4). [Figure 10] (A) is an image of the surface of a commercially available double-embossed rice paddle, and (B) is an image of a detailed observation of the area around the convex part. [Figure 11] This is a cross-sectional SEM image of a single micro-depression formed experimentally by a single shot of media used in fine particle peening, an example of shot projection processing. [Figure 12] This is an SEM image of a cross section of a recess created by laser processing. DETAILED DESCRIPTION OF THE INVENTION

[0028] An embodiment of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to the embodiment described below.

[0029] To date, the inventors have been investigating the possibility of applying to various fields surface modification technology that uses a particle projection process (e.g., MD process, particle peening process, etc.), which is a type of shot projection process in which shot material is projected, to randomly form countless dimple-like minute irregularities on the surface of a component. To this end, they have taken various approaches to confirm the effects of forming countless minute irregularities on the surface of a component (the surface that comes into contact with the target object) in various fields.In the process, they have now obtained new knowledge that was previously unknown, which will be explained below while showing the experimental results.

[0030] The inlet size (inlet width of the inlet, opening width of the opening) of the micro-dimple recesses formed by shot projection processing (e.g., MD processing, fine particle peening processing, etc.) in which shot material is projected onto the surface of a component can be substituted by the unevenness pitch (the distance between adjacent recesses or the distance between adjacent protrusions) measured from the surface shape. Furthermore, shot projection processing can be described as a process that unevenly forms dimple-shaped micro-recesses on the surface and ridge-like protrusions around the recesses (forming multiple (countless) crater-shaped micro-recesses randomly on the surface).

[0031] In this embodiment, experiments were conducted using multiple types of shot projection processes (MD processes) with different specifications (different materials and sizes of shot material (media), different conditions for ejecting shot material, etc.), as well as multiple types of polishing processes (lapping processes) with different specifications. Some of these processes will be selected and explained below.

[0032] For sample (1), the surface of a substrate made of SUS304 stainless steel plate was polished with a #700 buff, and then a countless number of micro-recesses were randomly formed on the surface by shot projection processing (MD processing 1) according to specification 1, followed by polishing processing (polishing process 1) according to specification 1. MD processing 1 is a process in which shot projection processing is performed using, for example, ceramic media (alumina (Al2O3)) with a particle size of approximately 1 to 1.4 mm at a projection pressure of 1.0 MPa or less. Furthermore, polishing process 1 involves polishing using, for example, paper of approximately #800, followed by 3D lapping. The 3D lapping process will be described later.

[0033] A 3D image of the surface of sample (1) is shown in Figure 2(A). From FIG. 2(A), it was confirmed that recesses 10 were formed by the MD process 1, and flat portions (upper surfaces of the protrusions) 20 were formed around the recesses 10 by the polishing process 1. It was confirmed that sample (1) has the effect of inhibiting adhesion of cooked rice (rice grains). The adhesion-inhibiting effect was confirmed by placing a lump of cooked rice grains on top of the sample and rolling the lump over the sample to check the degree to which rice grains detach from the lump and adhere to the surface of the sample, or by checking the degree to which rice adheres to the surface of the sample when the sample is used to scoop up rice like a rice paddle. As shown in Figure 1, the surface shape data of sample (1) was Rz (μm) = 72.3, Ra (μm) = 5.81, Rk u= 5.07, Rs. k= The result was -1.43. These are the parameters for the profile curve method (line roughness) defined by JIS.

[0034] 3D lapping (three-dimensional polishing) is a process in which abrasive grains such as diamond with minute particle diameters (particle diameter 5 μm or less) carried by a resin (an elastically deformable carrier) are projected onto the object to be processed (workpiece). Since small abrasive grains (the resin carrier is about φ1mm to 2mm in size, and the diamond abrasive grains have a particle diameter of about φ0.25 μm to 1 μm) are used, they can penetrate into even the recesses of complex three-dimensional shapes and polish. That is, in this embodiment, when the upper surface of the convex portion between the concave portions is flattened by polishing, burrs that appear at the corners are removed by finishing processing such as 3D lapping, and by preventing the burrs from biting into sticky substances such as rice, the adhesion prevention effect can be effectively exerted.

[0035] The 3D images, surface shapes, and surface shape data in this embodiment, including those described below, were acquired using a shape measurement laser microscope VK-X100 manufactured by KEYENCE Corporation.

[0036] For sample (2), the surface of a similar stainless steel substrate was subjected to a shot blasting process (MD process 2) according to specification 2, in which countless micro-recesses were randomly formed, followed by a polishing process (polishing step 2) according to specification 2. MD process 2 involves blasting shots at a pressure of 1.0 MPa or less using ceramic media (alumina (Al2O3)) with a particle size of, for example, 0.3 to 0.425 mm. Furthermore, polishing step 2 involves polishing with, for example, paper of approximately 320 grit, followed by polishing with paper of approximately 800 grit, and then 3D lapping.

[0037] A 3D image of the surface of sample (2) is shown in Figure 2(B). From FIG. 2(B), it was confirmed that a recess 11 larger than Specification 1 formed by MD process 2 and a flat portion 21 formed around it by polishing process 2 were formed. It was confirmed that sample (2) has the effect of inhibiting adhesion of cooked rice (rice grains). As shown in Figure 1, the surface profile data for sample (2) was Rz (μm) = 91.4, Ra (μm) = 8.32, and Rk u= 3.37, Rs. k= It was -0.68.

[0038] For sample (3), a number of randomly formed micro-recesses were formed on the surface of a similar stainless steel substrate using shot projection processing (MD processing 2) according to specification 2, and then polishing processing (polishing process 1) according to specification 1 was performed. A 3D image of the surface of sample (3) is shown in Figure 2(C). From FIG. 2(C), it was confirmed that a recess 12 was formed in the MD process 2 and a flat portion 22 was formed around the recess 12 in the polishing process 1. It was confirmed that sample (3) has the effect of inhibiting adhesion of cooked rice (rice grains). As shown in Figure 1, the surface profile data for sample (3) was Rz (μm) = 145.3, Ra (μm) = 6.48, and Rk u= 4.91, Rs. k= It was -1.18.

[0039] For sample (4), the surface of a SUS304 stainless steel plate was polished with a #400 buff, and then a shot projection process (MD process 3) according to specification 3 was used to randomly form numerous micro-recesses on the surface. The MD process 3 was then polished with a shot projection process (polishing process 3) according to specification 3. For example, spherical ceramic media (ceria-stabilized zirconia (ZrO2: 78% or more, CeO2: 15% or more)) with a particle size of approximately 0.4 to 0.6 mm was used to project the shot at a projection pressure of 0.2 MPa or less. Furthermore, for example, the polishing process 3 involved polishing using #800 to #1000 paper, followed by finishing with a #8000 wrapping film sheet. As with 3D wrapping, the finishing process using a wrapping film sheet is a process in which burrs that form at the corners are removed by polishing the top surfaces of the convex portions between the concave portions to make them flat, thereby preventing the burrs from biting into sticky substances such as rice, thereby more effectively suppressing adhesion.

[0040] A 3D image of the surface of sample (4) is shown in Figure 2(D). From FIG. 2(D), it was confirmed that a recess 13 larger than specification 2 formed by MD process 3 and a flat portion 23 formed around it by polishing process 3 were formed. It was confirmed that sample (4) has the effect of inhibiting adhesion of cooked rice (rice grains). As shown in Figure 1, the surface profile data for sample (4) was Rz (μm) = 12.2, Ra (μm) = 0.87, and Rk u= 3.74, Rs. k= It was -0.81.

[0041] For sample (5), a large number of minute recesses were randomly formed on the surface of a similar stainless steel substrate by shot projection processing (MD processing 1) according to specification 1 (no polishing process was performed). A 3D image of the surface of sample (5) is shown in Figure 3(A). As can be seen from FIG. 3(A), countless recesses 14 are formed randomly by the MD process 1, but no flat areas formed by the polishing process as in samples (1) to (4) are formed around them. It was confirmed that sample (5) had no effect of inhibiting adhesion of cooked rice (rice grains). As shown in Figure 1, the surface profile data of sample (5) was Rz (μm) = 148.6, Ra (μm) = 8.38, Rk u= 3.52, Rs. k= It was -0.25.

[0042] For sample (6), a large number of minute recesses were randomly formed on the surface of a similar stainless steel substrate by shot projection processing (MD processing 2) according to specification 2 (no polishing process was performed). A 3D image of the surface of sample (6) is shown in Figure 3(B). As can be seen from FIG. 3(B), countless recesses 15 are formed randomly by the MD process 2, but no flat areas formed by the polishing process as in samples (1) to (4) are formed around them. It was confirmed that sample (6) had no effect of inhibiting adhesion of cooked rice (rice grains). As shown in Figure 1, the surface profile data for sample (6) was Rz (μm) = 126.6, Ra (μm) = 6.87, and Rk u= 3.85, Rs. k= It was -0.26.

[0043] For sample (7), a large number of minute recesses were randomly formed on the surface of a similar stainless steel substrate by shot projection processing (MD processing 3) according to specification 3 (no polishing process was performed). A 3D image of the surface of sample (7) is shown in Figure 3(C). As can be seen from FIG. 3(C), countless recesses 16 are formed randomly by the MD process 3, but no flat areas formed by the polishing process as in samples (1) to (4) are formed around them. It was confirmed that sample (7) had no effect of inhibiting adhesion of cooked rice (rice grains). As shown in Figure 1, the surface profile data of sample (7) was Rz (μm) = 14.5, Ra (μm) = 1.42, Rk u= 2.68, Rs. k= It was -0.13.

[0044] According to the experimental results of this embodiment, samples (1) to (4) were effective in suppressing adhesion of sticky substances such as cooked rice grains. These samples were made by forming countless random micro recesses using a shot projection process (MD process), and then flattening the formed protrusions using a polishing process. The surface shape data that is effective in preventing adhesion of adhesive substances is shown in Figure 1: Rz = 10 to 150 μm, Ra = 0.5 to 10 μm, Rku = 3.0 to 5. 5、 Rsk=-1.43~-0.6 In 8 there were.

[0045] Furthermore, when compared with a surface shape that does not have the effect of suppressing adhesion of adhesive substances, it is thought that it is possible to distinguish from a surface shape that has the effect of suppressing adhesion of adhesive substances by considering any or all of Rz, Ra, Rku, and Rsk in combination, but only the parameter Rsk was distinguishable alone.

[0046] Rsk will be explained with reference to FIG. Skewness (Rsk) is the cube mean of Z(x) over a dimensionless reference length, calculated by the cube of the root mean square height (Rq). It signifies the degree of distortion and indicates the symmetry of the peaks and valleys when the mean line is at the center. That is, Rsk=0 indicates a shape that is symmetrical (normal distribution) with respect to the mean line, Rsk>0 indicates a shape that is biased downward from the average line (a surface with remaining convexities), Rsk<0 indicates a shape that is biased upward relative to the average line (a surface where the convex portions have been scraped off).

[0047] Figure 8 shows the Rsk results for each sample, and according to this, taking into account variations, etc., it is -1. 6< Rsk<-0. 3、 Or -1. 5< Rsk<-0. 4 in If so, it was found that the surface has the effect of inhibiting adhesion of sticky substances.

[0048] Figure 5(A) shows the measurement results of the surface shape of sample (7) (MD treatment 3 only, no polishing process), and Figure 5(B) shows the measurement results of the surface shape of sample (4) (MD treatment 3 + polishing process 3). As can be seen from Figure 5(A) of the surface shape of sample (7) (MD treatment 3 only, no polishing process), the heights of the convex parts of the unevenness formed on the surface are not uniform. Furthermore, based on the observation in Figure 3(C), it is thought that the amount of protrusion (ridge height) around the concave parts formed by the impact of the shot material is also random, since the convex parts are only the ridge parts formed around the concave parts.

[0049] The width of the recess entrance of the unevenness formed on the surface of sample (7) was 48.7 to 141.4 μm, and the recess depth related to the unevenness pitch was 2.76 to 4.80 μm.

[0050] On the other hand, as can be seen from Figure 5(B), the surface shape of sample (4) (MD treatment 3 + polishing process 3) shows that the heights of the convex parts (around the concave parts) of the unevenness formed on the surface are uniform, and it was confirmed that fine scratches (visually streak-like scratches) caused by the polishing process were formed randomly on the relatively flattened tip surfaces of the convex parts (the surfaces above the convex parts in Figure 5(B)). Since polishing was performed from random directions using a relatively coarse abrasive, the streak-like scratches were also formed randomly.

[0051] The width of the recess entrance of the unevenness formed on the surface of sample (4) was 68.8 to 106.0 μm, and the recess depth related to the unevenness pitch was 2.36 to 3.07 μm. Furthermore, the width of the polishing marks (streak-like scratches) randomly formed on the surface including the flat portion 23 (top surface of the convex portion) around the concave portion formed in sample (4) was approximately 3.5 to 8.5 μm, and their depth was approximately 0.5 to 2.0 μm (see FIG. 7).

[0052] The measurement results of the surface shapes of samples (1) to (3) are shown in Figure 6. As with sample (4) in Figure 5(B), samples (1) to (3) also showed that the heights of the convex portions (around the concave portions) of the uneven surface formed were uniform, and that fine scratches (visually streak-like scratches) due to the polishing process were formed on the upper surfaces of the convex portions (on the top surfaces of the convex portions) that had been relatively smoothed out.

[0053] The width of the recess entrance of the unevenness formed on the surface of sample (1) was 28.7 to 107.9 μm, and the depth of the recess related to the unevenness pitch was 12.8 to 27.3 μm. Furthermore, as shown in FIG. 7, the pitch (width) of the polishing marks formed on the surface including the flat portion 20 (top surface of the convex portion) around the concave portion formed in the sample (1) was about 2.5 to 10.0 μm, and the depth was about 0.5 to 1.5 μm.

[0054] The width of the recess entrance of the unevenness formed on the surface of sample (2) was 48.1 to 86.5 μm, and the recess depth related to the unevenness pitch was 16.9 to 28.7 μm. Furthermore, the pitch (width) of the polishing marks formed on the surface including the flat portion 21 (top surface of the convex portion) around the concave portion formed in sample (2) was approximately 3.0 to 10.0 μm, and the depth was approximately 1.5 to 8.0 μm (see FIG. 7).

[0055] The width of the recess entrance of the unevenness formed on the surface of sample (3) was 59.6 to 107.7 μm, and the recess depth related to the unevenness pitch was 18.9 to 31.7 μm. Furthermore, the pitch (width) of the polishing marks formed on the surface including the flat portion 22 (top surface of the convex portion) around the concave portion formed in the sample (3) was approximately 5.0 to 12.0 μm, and the depth was approximately 4.0 to 12.0 μm (see FIG. 7).

[0056] As mentioned above, all of the samples (1) to (4) have the effect of inhibiting adhesion of adhesive substances, but the effect of inhibiting adhesion of adhesive substances in samples (1) and (4) tended to be slightly higher than that in samples (2) and (3).

[0057] From the above, it was found that by randomly forming countless tiny irregularities on the surface of a component using a shot projection process, and then flattening the top surfaces of the convex parts surrounding the concave parts using a polishing process, it is possible to suppress the adhesion of sticky substances to the surface. It was also found that a component having a surface with countless randomly arranged irregularities, each with a flat upper surface surrounded by a minute concave portion, has the effect of suppressing adhesion of adhesive substances to its surface. The samples (1) to (4) according to the present embodiment correspond to an example of the member according to the present invention.

[0058] Furthermore, according to this embodiment, it has been confirmed that the adhesion suppression effect can be achieved simply by the surface shape having countless randomly arranged irregularities with flat upper surfaces surrounding the minute concave portions, and the material does not require coating with fluorine or the like, so there is no need to worry about peeling.

[0059] In other words, according to this embodiment, it is possible to provide a surface treatment method that can effectively suppress the adhesion of sticky substances such as rice without causing surface peeling and making the surface easy to clean, as well as components and utensils that have the effect of suppressing the adhesion of sticky substances to the surface.

[0060] Furthermore, from Figure 8, the skewness (Rsk) of the surface of a component with a surface that has minute irregularities and convex parts with flat upper surfaces around the concave parts is -1. 6< Rsk<-0. 3、 Or -1. 5< Rsk<-0. 4 in It has been found that in some cases it is effective in suppressing adhesion of sticky substances.

[0061] Furthermore, according to this embodiment, it was found that when the depth of the recesses of the surface irregularities having minute irregularities and convex portions with flat upper surfaces around the recesses is in the range of approximately 2 to 35 μm and the entrance width of the recesses is in the range of approximately 25 to 110 μm, there is an effect of suppressing adhesion of sticky substances.

[0062] Furthermore, according to this embodiment, it was found that an adhesion suppression effect against adhesive substances is achieved when the ratio of the total surface area of ​​the surface having minute irregularities and convex portions with flat upper surfaces around the concave portions to the surface area of ​​the upper surfaces of the convex portions (surface area of ​​the convex portions / total surface area) is in the range of approximately 46 to 61%, or in the range of 45 to 65% taking into account variations, as shown in Fig. 9. This ratio was obtained by analyzing the 3D image of Fig. 2 using a shape measurement laser microscope VK-X100 manufactured by KEYENCE Corporation.

[0063] Furthermore, a finishing process (lapping process or polishing process) can be carried out on the surface of a member having a surface with minute concaves and convex portions with flat upper surfaces around the concaves.

[0064] In the present invention, the adhesive substance includes not only adhesive substances (adhesive substances) that are formed after cooking grains such as rice, but also paste-like substances, miso, boiled udon noodles, and other adhesive substances other than food.Specific examples include cooked white rice, seasoned rice, fried rice, pilaf, risotto, etc.

[0065] Furthermore, the member according to the present invention can be applied to any member to which adhesion of adhesive substances is desired to be suppressed. Examples include rice scoops, ladles, spatulas, spoons, forks, knives (including butter knives), as well as storage containers and containers such as bowls and packs, tableware, cooking utensils such as kettles, pots, and frying pans, and even equipment that comes into contact with adhesive substances in production lines that handle adhesive substances (hoppers, transport containers, transport plates, stirring utensils such as stirring blades, cooking utensils such as spatulas, etc.).

[0066] Furthermore, in the present invention, forming an uneven surface having minute irregularities and convex portions with flat upper surfaces around the concave portions also includes cases where an uneven surface is formed on the surface of a component, for example, by transfer using a mold having an uneven surface on its surface formed based on (utilizing) chemical etching, plasma treatment, shot projection treatment, polishing treatment, etc.

[0067] Here, the shot projection process (or micro-roughness formation process, micro-dimple process) according to this embodiment can be carried out by using a known injection device to inject the above-mentioned media (shot material, abrasive particles) and collide them against the surface of the workpiece to be processed.

[0068] For example, a blasting device can be used as the injection device, and an example of the blasting device is the "PNEUMA BLASTER" (models: SC series, SG series, etc.) manufactured by Fuji Manufacturing Co., Ltd. Also, for example, the device described in JP 2019-25584 A can be used.

[0069] More specifically, as an injection device for injecting the injected particles toward the surface of the component, a known blasting device (blasting processing device) that injects abrasives (fine particles) together with compressed gas (air, argon, nitrogen, etc.) can be used.

[0070] As for blast processing equipment (blast processing devices), various types are commercially available, including suction-type blast processing equipment that uses the negative pressure generated by the injection of compressed gas to inject abrasives, gravity-type blast processing equipment that injects abrasives that have fallen from an abrasive tank, carried on compressed gas, direct pressure-type blast processing equipment that introduces compressed gas into a tank containing abrasives, and then combines the abrasive flow from the abrasive tank with the compressed gas flow from a separately provided compressed gas supply source and injects the abrasives, and blower-type blast processing equipment that injects the direct pressure-type compressed gas flow carried on a gas flow generated by a blower unit, all of which can be used to inject the aforementioned injection particles. Alternatively, a water jet can be used, which sprays a shot at high pressure along with a liquid such as water.

[0071] Incidentally, in this embodiment, it has been described that countless (multiple, many) minute irregularities are randomly formed by a shot projection process, but it is also possible to randomly form countless (multiple, many) minute irregularities on the surface of a component by, for example, chemical polishing (chemical etching) or plasma treatment (e.g., argon bombardment treatment). For chemical polishing (chemical etching), it is expected that an aqueous solution of, for example, acidic agents such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, or iron (III) chloride may be prepared in any ratio and used.

[0072] Furthermore, this embodiment can achieve the same effect with any stainless steel material, particularly non-magnetic austenitic stainless steel (SUS303, 304, 316, etc.), regardless of the surface finish specifications of the base material before treatment, such as #400, #700, 2B, etc. The present invention can also be applied to metal materials other than stainless steel (for example, in the case of iron, metals or alloys such as steel (SS400, etc.), aluminum, titanium, etc.).

[0073] The members according to the present invention may be made of resin, and the material is not particularly limited. For example, ceramics may be used. The method of surface treatment of a member to inhibit adhesion of adhesive substances according to the present invention is also a method of producing a member that has been subjected to the surface treatment to inhibit adhesion of adhesive substances.

[0074] Here, in the present invention, in order to identify from the shape or structure of an uneven surface formed by (or based on) shot projection processes such as micro-roughness formation processes, micro-dimple processes, and fine particle projection processes, or chemical etching or plasma processes (hereinafter, these will be simply referred to as shot projection processes), a method of identification is used in which, completely different from the geometric and regular uneven shapes formed according to pre-designed drawings using laser processing or the like, countless dimple-shaped minute recesses and ridge-like protrusions around the recesses are formed randomly, each with their own shape, pitch, and depth. That is, instead of using the expression "micro recesses are formed on the surface by (or based on) a shot projection process," a specific method (expression) such as "countless micro irregularities are randomly formed on the surface of the component" is used. However, in comparison with prior art, it is conceivable that the above-mentioned identification method (expression) may make it difficult to adopt the uneven surface formed by the shot projection process as a distinctive identification method (expression) that distinguishes it from others.

[0075] For this reason, it is conceivable that there will be a situation in which it will be necessary to identify an uneven surface formed by (or based on) a shot material projection process using the identification method (expression) of "forming minute unevenness on the surface by (or based on) a shot material projection process." Therefore, at the time of filing this application, there were circumstances that made it impossible or unrealistic to specify the shape, structure, characteristics, etc. of the minute irregularities formed by the shot projection process, and we will explain below why there are cases where we have no choice but to use the expression "by forming minute irregularities on the surface by (or based on) the shot projection process (taking into account cases such as transfer)."

[0076] In shot projection processing, projected particles (media) are collided with the surface of the workpiece using compressed air at speeds of several tens to over a hundred meters per second, forming irregular, micron-sized, roughly spherical micro-depressions with convex edges over almost the entire surface of the workpiece without causing any significant dimensional change. When the media collides to form the micro-depressions in the shot projection processing, the surrounding area rises in a crater-like manner, forming convex portions (see Figure 11). These raised convex portions are then depressed by collisions with other media, resulting in irregular convex portions of irregular height.

[0077] In contrast, mechanical processes such as laser processing and cutting create regular recesses and do not create convexities because they are removal processes (the formation of recesses does not result in the formation of convexities).For this reason, the height of the convexities around minute recesses in mechanical processes such as laser processing and cutting matches the height of the surface (original material surface) of the workpiece (the component being laser processed) (see Figure 12).

[0078] Furthermore, since the minute irregularities formed by the shot projection process are formed in an infinite number of irregular (random) patterns, the surface texture (shape) formed by the shot projection process differs from the surface shape (texture) formed by processes such as polishing and grinding, which scrape the surface and create scratches (grooves such as streaks).However, when measured using a surface roughness meter, the two end up with similar numerical values, so it is not possible to distinguish between the two based on surface roughness, etc.

[0079] However, the effects obtained by the surface texture (shape) formed by the shot projection process (such as contribution to inhibiting adhesion of sticky substances) are exceptional and cannot be predicted from the surface shape (texture) formed by processes that scrape and scratch the surface, such as polishing or grinding. Furthermore, shot peening, which involves colliding media of the order of several millimeters to impart residual stress and improve the fatigue limit, makes it impossible to predict that a surface that has been subjected to shot projection treatment would contribute to the prevention of adhesion of sticky substances.

[0080] In this way, the minute irregularities formed by the shot projection process are formed in an infinite number of irregular (random) patterns, the shapes of the minute concaves and convexities around them are irregular, and in light of this irregularity being the source of the effects achieved by the present invention, it is not possible to specify the surface formed by the shot projection process other than by using the expression "formed by the shot projection process" as a term for specifying the surface texture (shape) formed by the shot projection process. As described above, at the time of filing this application, it is impossible or impractical to specify the shape, structure, characteristics, etc. of the minute irregularities formed by the shot projection process.

[0081] The present invention is not limited to the above-described embodiment of the invention, and various modifications can be made without departing from the spirit of the present invention. [Industrial Applicability]

[0082] The present invention can impart an effect of inhibiting adhesion of adhesive substances to the surface of a member, and is useful and applicable in industries that handle adhesive substances. [Explanation of symbols]

[0083] 10, 11, 12, 13 recesses 20, 21, 22, 23 Flat part (top surface of convex part)

Claims

1. A countless number of minute irregularities are randomly formed on the surface of the member, and the upper surfaces of the protrusions around the recesses are flattened. A surface treatment method for inhibiting adhesion of adhesive substances to a member, which has an effect of inhibiting adhesion of adhesive substances formed after cooking grains to the surface of the member by setting the skewness "Rsk" of the surface of the member to -1.43≦Rsk≦-0.68, A surface treatment method for preventing adhesion of adhesive substances to a member, characterized in that the depth of the recesses in the uneven surface of the member is in the range of 2 to 35 μm and the entrance width of the recesses is in the range of 25 to 110 μm.

2. A surface treatment method for preventing adhesion of adhesive substances to a member as described in claim 1, characterized in that the ratio of the total surface area of ​​the uneven surface to the surface area of ​​the upper surfaces of the convex portions is 45 to 65%.

3. The minute irregularities are Based on at least one of a shot projection process, chemical etching, or plasma treatment 3. The method for surface treatment of a member to inhibit adhesion of adhesive substances according to claim 1 or 2, further comprising forming a surface layer on the member.

4. 4. The method for surface treatment of a member to inhibit adhesion of adhesive substances according to claim 1, wherein the upper surfaces of the convex portions are flattened by polishing, and a finishing process is carried out after the polishing.

5. 5. The method for surface treatment of a member to prevent adhesion of adhesive substances according to claim 4, wherein the finishing process is a three-dimensional polishing process.

6. The surface has a countless number of irregularities randomly arranged, each having a flat upper surface surrounded by a concave portion of the minute concave portion, and A member having a surface skewness "Rsk" of -1.43≦Rsk≦-0.68, which has an effect of suppressing adhesion of sticky substances formed after cooking grains to the surface, A member characterized in that the depth of the recesses in the surface irregularities is in the range of 2 to 35 μm and the entrance width of the recesses is in the range of 25 to 110 μm.

7. 7. The member according to claim 6, wherein the ratio of the total surface area of ​​the uneven surface to the surface area of ​​the upper surfaces of the projections is 45 to 65%.

8. 8. The member according to claim 6, wherein the uneven surface is provided in a portion that comes into contact with an adhesive substance.

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