JP2023078880A - Resin molded article and knurl - Google Patents

Abstract

To provide a resin molded article having a rubber-like ultra low-gloss surface, and having a scratch-resistant characteristic.SOLUTION: A large number of protrusions are arranged in a honeycomb pattern on an appearance surface. A distance between adjacent protrusions among the large number of protrusions is longer than 5 μm and shorter than 100 μm.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a resin molded product and a knurl having a rubber-like ultra-low gloss surface.

In order to improve the appearance quality such as design and texture only by molding plastic products without painting, a process called embossing is sometimes applied on the mold. There are many types of embossing, one of which is to give a texture called matte feeling with low gloss. Generally, it is performed by providing fine unevenness to the surface of the mold by etching or blasting. By doing this, a fine uneven shape is transferred to the surface of the molded product, and this uneven shape scatters the reflected light on the surface of the molded product in various directions, lowering the gloss and giving a matte feeling (low gloss). It is. On the other hand, the surface of a molded product with a matte feel has the disadvantage that it is easily scratched when it is rubbed with a hard object during handling. When something harder than resin touches the molded product, the stress is concentrated on the convex part of the uneven surface, causing deformation, and the degree of light scattering is different from the surroundings, so it is recognized as a scratch. be. As means for solving such drawbacks, for example, the techniques disclosed in Patent Document 1 and Patent Document 2 can be used. According to the technique of Patent Document 1, when the surface comes into contact with a hard object, the protruding portion comes into contact first, and the roughened portion located at a relatively low portion is protected, thereby making it less likely to be damaged. . Further, in Patent Document 2, the shape of the irregularities on the surface of the mold is made shallow by a post-treatment to make scratches on the surface of the molded article less noticeable.

Japanese Patent Laid-Open No. 9-239739 Japanese Patent Laid-Open No. 8-332639

However, even with conventional techniques, it is difficult to obtain a rubber-like ultra-low-gloss surface, and it has been desired to further suppress the perception of scratches.

The present invention is a resin molded article characterized in that a large number of protrusions are arranged in a honeycomb pattern on an exterior surface.

Further, the present invention is characterized by a resin knurl having a plurality of projections arranged in alignment, wherein a large number of projections are arranged in a honeycomb pattern on the surfaces of the plurality of projections.

According to the resin molded product of the present invention, it is possible to obtain a molded product that has a rubber-like ultra-low-gloss surface and is resistant to scratches even if it is made of resin.

Diagrams for explaining the first embodiment Diagrams for explaining the first embodiment Diagrams for explaining other embodiments Diagrams for explaining other embodiments Diagrams for explaining other embodiments Diagrams for explaining the first embodiment Diagrams for explaining the first embodiment Diagrams for explaining the first embodiment Diagram showing the reflection of incident light on a flat area Diagrams for explaining the first embodiment Diagrams for explaining other embodiments Diagrams for explaining the second embodiment Diagrams for explaining other embodiments Diagrams for explaining the first embodiment Diagrams for explaining the first embodiment Diagrams for explaining the first embodiment The figure which observed the surface of Example 1. The figure which observed the surface of Example 2. The figure which observed the surface of Example 3 Diagrams for explaining the second embodiment Diagrams for explaining the second embodiment Diagrams for explaining the second embodiment Diagrams for explaining the second embodiment

(First embodiment)
FIG. 1 is a diagram for explaining the characteristics of the appearance surface shape (surface shape) of the resin molded product of the present invention, and is a conceptual diagram enlarging a part of the surface area. In addition, the figure expresses the surface of the resin molded product as if viewed from an oblique direction. In FIG. 1, 1 is the surface of the molded article. 4 represents a plane parallel to the average plane of the molded article surface, and 5 represents the average normal direction. A feature of the resin molded product of the present invention is that the protrusions 2 are densely present. Being densely present means that they are preferably arranged in a honeycomb shape. In the present invention, the honeycomb arrangement refers to a state in which one convex portion 17 is surrounded by six convex portions (171 to 176) as shown in FIG. Furthermore, it is more preferable that six adjacent protrusions (171 to 176) surround one protrusion 17 at regular intervals. That is, the distances (L1 to L6) between the vertex (P1) of the convex portion 17 in FIG. 10 and the vertex (P2, P3, P4, P5, P6, P7) of the six adjacent convex portions are the same length. is more preferable. In the present invention, equal intervals may include a certain amount of error, and even if the distances (L1 to L6) include an error of ±10 μm or less, they are equal intervals.

With the honeycomb arrangement, the density of the protrusions per unit area can be increased and made uniform. By doing so, it is possible to disperse the stress generated when it comes into contact with a nail or the like, so deformation is less likely to occur.

It is preferable that the convex portion has a hemispherical shape, the width of which becomes narrower toward the top. When h/p is the value obtained by dividing the height h of a convex portion by the distance p between adjacent convex portions, the height of the convex portion increases, and the glossiness decreases as the h/p value increases. know. Gloss can be measured using a common gloss meter. For example, the gloss meter IQ FLEX 60 from the company PHOPOINT instruments can be used. According to measurements by the present inventors, a glossiness of 3 or less is preferable to obtain a rubber-like appearance, and a good appearance is obtained when the h/p value exceeds about 0.07, and the h/p value is 0. Above 0.05, the appearance becomes closer to that of rubber. On the other hand, however, when the h/p value is further increased, it tends to be easily scratched. That is, the h/p value is preferably 0.05 or more and 0.30 or less. It is more preferably 0.06 or more and 0.20 or less, and still more preferably 0.07 or more and 0.10 or less.

Further, in the resin molded product of the present invention, the distances (L1 to L6) between adjacent projections are preferably longer than 5 μm and shorter than 100 μm. If the length is longer than 100 μm, the irregular shape on the surface of the molded product may be identified, and the texture may appear rough to the eye. On the other hand, if it is shorter than 100 μm, a person with normal vision cannot recognize the uneven shape, and the texture can be perceived as being equivalent to the matte texture produced by blasting or etching. Also, from the viewpoint of scratch resistance, it is advantageous to shorten the distance between the tops of the projections. If the distance between the tops of the protrusions is short, the density of the protrusions per unit area will be high, and the number of protrusions that are in contact at the same time will increase, reducing the stress generated by each protrusion, making it less likely to be scratched. Become. For these reasons, it is desirable that the distance between the tops of the projections is shorter than 100 μm. Furthermore, it is desirable that the length is shorter than 50 μm. When the molded product is observed outdoors under the sunshine on a sunny day or indoors under a strong spotlight, the texture appears rough even if the distance between the tops is shorter than 100 μm. There is Even under such special observation conditions, the texture is improved when the distance between the tops is shorter than 50 μm.

Also, assuming contact with a human nail, it is necessary to take into consideration the destruction of the surface due to catching on the unevenness of the nail surface. According to observations made by the present inventors, fine irregularities of several μm or less are present on the surface of the nail. If unevenness of the same size as this unevenness is present on the surface of the molded product, the claw and the unevenness of the molded product are likely to be damaged by engaging each other. For this reason, it is desirable that the vicinity of the apex of the protrusion, which is likely to come into contact with the nail, be smooth without fine irregularities. Further, it is desired that the distance between the tops of the projections is several μm or more, preferably 5 μm or more. On the other hand, the portions apart from the tops of the projections, which are hard to come into contact with the claws, do not necessarily have to be smooth. FIG. 11 shows another embodiment of the molded article of the present invention. The figure shows an example in which the surface 1 of the molded product is smooth in the vicinity of the top of the projection 2, but has finer unevenness 18 in the vicinity of the bottom apart from the top. In this way, the fine unevenness 18 is relatively easily deformed when it comes into contact with the nail, but may exist in a portion away from the top of the convex region. In other words, the surface roughness of the bottom of the projection is rougher than the surface roughness of the top of the projection. Surface roughness can be measured by, for example, a laser microscope or an atomic force microscope. It is possible to divide the height of the convex portion in half, measure 5 points each in a region higher than half including the vertex and a region lower than half, and compare the average values.

As shown in FIG. 1, a convex portion is defined as having a convex curvature in the direction of the normal 5 . Further, the surface of the resin molded product of the present invention may have recesses 3 . A concave portion is defined as having a concave curvature toward the outside in the normal direction in a cross section that includes the apex of the adjacent convex portion and is located between the convex portions and perpendicular to the surface of the molded product. FIG. 2 shows the cross-sectional shape of the surface shape 1 of the molded product in FIG. 1 along the line A-A'. This section A-A' passes through the vertices of the adjacent convex portions. In FIG. 2, 5 is the average normal direction of the surface of the molded product, 2 is the convex portion, and 3 is the concave portion. Also, the surface of the molded product of the present invention can have a cross-sectional shape as shown in FIG. FIG. 3 shows another embodiment of the cross section taken along line A-A' of FIG. In the case of the shape shown in FIG. 3, the recesses 3 in FIG. FIG. 4 shows another example of the resin molded product of the present invention. FIG. 4 shows another embodiment of the A-A' section of FIG. This section A-A' also passes through the vertices of the adjacent convex regions. In FIG. 4, 5 is the average normal direction of the surface of the molded product, 2 is the convex portion, and 3 is the concave portion. As a feature of the figure, there is a bending point 6 between the convex portion 2 and the concave portion 3 . In this manner, the resin molded product of the present invention may have a bending point between the convex portion and the concave portion. As shown in FIGS. 2 to 4, the surface of the resin molded product of the present invention can be covered with only the projections 2, or can have recesses 3 in addition to the projections 2. FIG. At least the vicinity of the apex of the projection has a smooth shape. Normally, to obtain a matt feeling, a fine irregular uneven structure is imparted. It allows you to reproduce the feeling. The principle will be explained below.

FIG. 5 is an enlarged view of a part of FIG. 2, and shows how the incident light that is incident on the convex portion is reflected. In the figure, 2 indicates a convex portion and 3 indicates a concave portion. An arrow 7 indicates incident light, and all five arrows indicate a state in which parallel light is incident on the convex portion 2 . On the other hand, the arrow of 8 is reflected light. Since the inclination state of the surface of the convex portion 2 differs depending on the location, even if the incident light beams are parallel to each other, the directions of the reflected light beams are directed in various directions. FIG. 6 is an enlarged view of a portion of FIG. 2, similar to FIG. 5, and shows how the incident light is reflected on the concave portion. In the figure, 2 indicates a convex portion and 3 indicates a concave portion. An arrow 7 indicates incident light, and all five arrows indicate a state in which parallel light is incident on the concave portion 3 . The arrow at 8 is the reflected light. Since the slope of the surface of the concave portion 3 differs depending on the location, even if the incident light beams are parallel to each other, the reflected light beams are directed in various directions as in the case of the convex portion. As shown in FIGS. 5 and 6, both the protrusions and recesses have the effect of reflecting light in various directions.

FIG. 7 is a diagram showing how a plate-shaped resin molded product is observed with a light source. 9 is a resin molded product of the present invention, and the surface of 10 has a shape as shown in FIGS. 13 represents the observer. Reference numeral 11 denotes a light source, and reference numeral 7 represents light rays emitted from the light source 11 in various directions and incident on a certain region of the resin surface. This incident light 7 is reflected in various directions for the reasons explained in FIGS. The arrows of 8 are reflected light, and represent how it goes in various directions. Further, 12 represents the angle at which the reflected light spreads, and the surface of the molded product with a small angle has a high glossiness. On the other hand, if this angle is large enough, the glossiness will be low, and you will feel a super low gloss texture like rubber. FIG. 8 is an enlarged view of a portion of FIG. 2, similar to FIGS. 5 and 6, and 2 is one of the projections. 5 represents the normal direction of the surface of the molded product. 14 is the normal line of the most inclined portion of the convex portion. Reference numeral 15 denotes an angle between the normal line 5 of the surface of the molded product and the normal line 14 of the most inclined portion. According to experiments conducted by the present inventors, when the angle 15 exceeds 10°, the angle 12 in FIG. 7 widens sufficiently to obtain a matte feeling. In this specification, the normal direction of the surface of the molded article is the perpendicular line of the imaginary plane connecting the apexes. That is, a 5 mm cross section of the molded product is cut out so as to include the top (section AA' in FIG. 1), and the line perpendicular to the line connecting the tops is taken as the normal direction of the surface of the molded product. In addition, the normal line of the most inclined part (maximum inclined part) in the convex part is cut out 5 mm from the cross section of the molded product like the AA' cross section in FIG. Find the place where the slope is the most (maximum slope), and take the average of the normals.

As described above, the surface of the molded product of the present invention can be covered only with the projections 2 as shown in FIG. On the other hand, it is preferable that flat regions other than the convex portions 2 and the concave portions 3 do not exist at all, or if they do exist, they occupy 10% or less of the surface. The manner in which incident light is reflected in such a flat area will be explained with reference to FIG. In FIG. 9, reference numeral 16 denotes a flat area that is neither convex nor concave. The arrow 7 is the incident light, and the five arrows all represent the state in which the parallel light is incident on the flat area of the surface of the molded product. And the arrow of 8 is reflected light. In such a flat area, the incident light is reflected in substantially the same direction because the inclination of the surface is constant even if the location changes. When the ratio of the flat area to the surface of the molded product exceeds 10%, when observing the molded product as shown in FIG. It will spoil the ultra-low gloss texture like a slippery rubber.

Next, the method for manufacturing the resin molded product of the present invention will be described.

As an example of the method for manufacturing a resin molded product of the present invention, an example of manufacturing a plate-shaped resin molded product will be shown. First, a mold 24 as shown in FIG. 14 is produced by cutting. Materials commonly used for molds can be used as the material for this mold. For example, STAVAX (Uddeholm) can be used. Next, the surface 25 of the mold 24 is given an uneven shape by laser processing. A well-known technique can be used for laser processing. Short pulse lasers such as nanosecond, picosecond and femtosecond lasers are preferably used. A short-pulse laser makes it possible to machine a minute hole shape while reducing the thermal influence on the periphery of the machined region on the surface of the material. However, the laser is not limited to this, and other lasers may be used.

FIG. 15 is an enlarged view in the cross-sectional direction showing how the mold surface is processed by the laser processing machine. In FIG. 15A, the laser beam 27 is held at one point, the irradiation point is moved so that the dot-to-dot interval P is 100 μm or less, preferably 50 μm, and the laser pulse is repeatedly irradiated. A depression 28 is formed on the mold 26 by this irradiation. After that, the irradiation point is moved and the laser pulse is irradiated while staying again. By repeating this process, a large number of fine dots can be processed. In this manner, the mold shown in FIG. 14 is produced.

Subsequently, injection molding is performed using this mold. The resin may be any resin that can be injection molded. In the injection process, the shape processed in the mold is transferred to the molded product by using molding conditions that sufficiently transfer the shape of the mold, and a resin molded product 29 as shown in FIG. 16 can be produced.

(Second embodiment)
22 and 23 are diagrams showing a second embodiment of the present invention. Reference numeral 33 in FIG. 22(a) denotes a knurling made of a resin molded product that can be used, for example, for a focus ring or zoom ring of a camera lens as shown in 21 in FIG. FIG. 22(b) is an enlarged view of B surrounded by a dotted line in FIG. 22(a). As shown in FIG. 22(b), a plurality of projections 34 are formed on the surface of 33. As shown in FIG. Each of the multiple protrusions 34 has a top surface 341 and a side surface 342 , and bottom surfaces 343 are arranged in alignment between the protrusions 34 . A large number of projections 2 described in the first embodiment are densely arranged on the surfaces (upper surface 341 and side surfaces 342) of the plurality of projections 34 and the bottom surface 343 between the projections 34. As shown in FIG. FIG. 23 is a diagram showing a state of the surface of FIG. 22(b) observed with an electron microscope. A large number of protrusions 2 are densely arranged. This makes it possible to obtain a rubber-like ultra-low gloss surface even with commonly used resin materials such as polycarbonate. The height of the projections 34 is determined not only by the difficulty of slipping when touched with a finger and by the tactile sensation but also by the design, and is generally 0.2 mm or more and 1.0 mm or less. More preferably, it is 0.3 mm or more and 0.6 mm or less. The height of the projection 34 is the top of one of the many protrusions 2 formed on the bottom surface 343 from a virtual extension plane obtained by extending a virtual plane connecting the tops of the many protrusions 2 formed on the top surface 341. shall be the length of the perpendicular to

Since the resin molded product shown in FIGS. 22A and 22B has a cylindrical shape, it can be manufactured using the mold shown in FIG. 20, for example. In the figure, 24 is an inner mold. On the other hand, the outer mold can be divided into 6 parts as shown by 25 to 30, and can be opened and closed by sliding motion. In order to form a shape generally called knurling on the surface of the cylindrical molded product, the outer mold is cut to have an uneven shape corresponding to the knurling, such as the surface 31 of the mold 25. Next, laser processing is applied to the mold surface in the same manner as in the first embodiment. FIG. 21 shows the process. First, as shown in FIG. 21(a), processing can be performed by adjusting the direction of the laser 27 so that the uneven bottom portion of the mold 32 is irradiated from the normal direction of the processing surface. Next, as shown in FIG. 21B, processing can be performed by adjusting the direction so that the laser is irradiated from the normal direction of the processing surface to the contiguous inclined surfaces as well.

Next, as shown in FIG. 21(c), processing is performed by adjusting the direction so that the laser is irradiated from the normal direction of the processing surface to the contiguous apexes of the concavo-convex shape. Next, as shown in FIG. 21(d), processing is performed by adjusting the direction so that the laser is irradiated from the normal direction of the processing surface to the contiguous inclined surfaces.

Subsequently, by performing injection molding using these molds, the knurl of the present invention can be manufactured.

(Other embodiments)
FIG. 13 shows an example of still another resin molded product to which the present invention can be applied. For example, the exterior component 22 of the top plate of the printer and the exterior component 23 of the side surface can be mentioned. The present invention is not limited to the resin-molded products of cameras and printers listed here, but can also be applied to resin-molded products of other products.

In this example, a plate-shaped resin molding having a matte texture was produced. First, a mold 24 as shown in FIG. 14 was produced by cutting. STAVAX (Uddeholm) was used as the material for this mold. Next, the surface indicated by 25 of this mold 24 was provided with an uneven shape by a laser processing device. LP400U (GF Machining Solutions) was used as a laser processing device. The wavelength of the laser used is 1064 nm. This laser is a nanosecond pulse laser, and can perform fine shape processing while reducing the thermal influence on the periphery of the processing area. The laser irradiation conditions at this time were a pulse width of 4 ns, an output of 30%, and a frequency of 750 kHz.

FIG. 15 is an enlarged view in the cross-sectional direction showing how the mold surface is processed by the laser processing machine. In FIG. 15(a), the laser beam 27 was held at one point, during which the laser pulse was repeatedly irradiated under the conditions described above. The residence time for irradiation was 10 ms. A depression 28 is formed on the mold 26 by this irradiation. After that, the irradiation point was moved and the laser pulse was irradiated while staying again. By repeating this process, a large number of fine dots were processed. The interval P between dots was set to 50 μm. In this manner, the mold shown in FIG. 14 was produced.

Subsequently, injection molding was performed using this mold. The molding machine used was a J180ELIII injection molding machine (Japan Steel Works, Ltd.). The resin used is Panlite G-3430R manufactured by Teijin Limited, which contains about 30% glass filler and is colored black. In the injection process, molding conditions were used to sufficiently transfer the shape of the mold, and the shape worked into the mold was transferred to the molded product, thereby producing a resin molded product 29 as shown in FIG.

FIG. 17 shows the appearance of the surface of the resin molded product manufactured in this example as observed with an electron microscope. Further, it was confirmed by shape measurement with a laser microscope that the inclination angle of the convex regions was 10° or more. When the texture of the surface of the resin molded product produced in this example was visually observed, each unevenness on the surface was difficult to identify, so the surface is said to be smooth and matte with a low gloss value. It was confirmed that texture was obtained. A scratch test was then performed on the molding. The scratch test was carried out by pressing a nail against the test piece with a load of 100 gf, moving a distance of 30 mm in 1 second, then observing the surface and judging by the degree of traces remaining. As a result, no outstanding marks were observed on the surface.

A metal mold and a plate-shaped resin molding were produced in the same manner as in Example 1 except for the laser irradiation conditions. STAVAX (Uddeholm) was used as the material of the mold. The laser irradiation conditions were a pulse width of 4 ns, an output of 30%, a frequency of 750 kHz, and a residence time of 5 ms during dot processing. The interval between dots was set to 50 μm.

FIG. 18 shows the appearance of the surface of the resin molded product manufactured in this example as observed with an electron microscope. Further, it was confirmed by shape measurement with a laser microscope that the inclination angle of the convex regions was 10° or more. When the texture of the surface of the resin molded product produced in this example was visually observed, each unevenness on the surface was difficult to identify, so the surface is said to be smooth and matte with a low gloss value. It was confirmed that texture was obtained. A scratch test was then performed on the molding. The scratch test was carried out by pressing a nail against the test piece with a load of 100 gf, moving a distance of 30 mm in 1 second, then observing the surface and judging by the degree of traces remaining. As a result, no outstanding marks were observed on the surface.

A metal mold and a plate-shaped resin molding were produced in the same manner as in Example 1 except for the laser irradiation conditions. SUS420J2 was used as the material of the mold. The laser irradiation conditions were a pulse width of 4 ns, an output of 30%, a frequency of 750 kHz, and a residence time of 5 ms during dot processing. The interval between dots was set to 50 μm.

FIG. 19 shows the appearance of the surface of the resin molded product manufactured in this example as observed with an electron microscope. Further, it was confirmed by shape measurement with a laser microscope that the inclination angle of the convex regions was 10° or more. When the texture of the surface of the resin molded product produced in this example was visually observed, each unevenness on the surface was difficult to identify, so the surface is said to be smooth and matte with a low gloss value. It was confirmed that texture was obtained.

A scratch test was then performed on the molding. The scratch test was carried out by pressing a nail against the test piece with a load of 100 gf, moving a distance of 30 mm in 1 second, then observing the surface and judging by the degree of traces remaining. As a result, no outstanding marks were observed on the surface.

A molded article that can be used as a focus ring or a zoom ring of a camera lens as shown in 21 in FIG. 12 was produced. Since the molded product in this case has a cylindrical shape, a mold as shown in FIG. 20 was produced. In the figure, 24 is an inner mold. On the other hand, the outer mold was divided into 6 parts as indicated by 25 to 30, and the mold was made openable and closable by sliding motion. STAVAX (Uddeholm) was used as the material of the mold. In order to form a shape generally called knurling on the surface of the cylindrical molded product, the outer mold was machined to have an uneven shape corresponding to the knurling, such as the surface 31 of the mold 25, for example. Next, the mold surface was subjected to laser processing under the same conditions as in Example 1. FIG. 21 shows the process. First, as shown in (a), the uneven bottom portion of the mold 32 was processed by adjusting the direction so that the laser 27 was irradiated from the normal direction of the processing surface. Next, as shown in (b), processing was performed by adjusting the direction so that the laser was irradiated from the normal direction of the processing surface to the contiguous inclined surfaces.

Next, as shown in (c), the apexes of the contiguous concave-convex shape were processed by adjusting the direction so that the laser was irradiated from the normal direction of the processed surface. Next, as shown in (d), processing was performed by adjusting the direction so that the laser was irradiated from the normal direction of the processing surface to the contiguous inclined surfaces.

Subsequently, injection molding was performed using these molds. The molding machine used was a J180ELIII injection molding machine (Japan Steel Works, Ltd.). The resin used is Panlite G-3430R manufactured by Teijin Limited, which contains about 30% glass filler and is colored black. In the injection process, molding conditions were used to transfer the shape of the mold sufficiently, and the shape worked into the mold was transferred to the molded product, thereby producing a resin molded product 33 as shown in FIG. 22(a). FIG. 22(b) is an enlarged view of the region B in (a).

FIG. 23 shows the appearance of the surface of the resin molded product manufactured in this example as observed with an electron microscope. Further, it was confirmed by shape measurement with a laser microscope that the inclination angle of the convex regions was 10° or more. When the texture of the surface of the resin molded product produced in this example was visually observed, each unevenness on the surface was difficult to identify, so the surface is said to be smooth and matte with a low gloss value. A texture was obtained, and it was confirmed that the appearance was similar to that of parts made of rubber. A scratch test was then performed on the molding. The scratch test was carried out by pressing a nail against the test piece with a load of 100 gf, moving a distance of 30 mm in 1 second, then observing the surface and judging by the degree of traces remaining. As a result, no outstanding marks were observed on the surface.

REFERENCE SIGNS LIST 1 surface of molded product 2 convex portion 3 concave portion

Claims (12)

1. A resin molded article, wherein a large number of protrusions are arranged in a honeycomb pattern on an exterior surface, and a distance between adjacent protrusions among the plurality of protrusions is longer than 5 μm and shorter than 100 μm. 2. The molded resin product according to claim 1, wherein the surface roughness of the tops of the plurality of projections is smaller than the surface roughness of the bottoms of the plurality of projections. 3. The molded resin article according to claim 1, wherein the distance between adjacent projections is longer than 5 [mu]m and shorter than 50 [mu]m. 4. The ratio h/p is larger than 0.05 and smaller than 0.3, where h is the height of the protrusions and p is the distance between adjacent protrusions. or the resin molded product according to one item. 5. The molded resin product according to claim 1, wherein an angle formed by a normal line of the outer surface and a normal line of the maximum inclined portion of the convex portion is 10[deg.] or more. 6. The method of manufacturing a resin molded product according to claim 1, wherein the resin molded product is molded by transferring a mold processed by laser processing. What is claimed is: 1. A knurl made of a resin having a plurality of protrusions formed on its outer surface, characterized in that a large number of protrusions are arranged in a honeycomb pattern on the surface of the plurality of protrusions. 8. The knurl according to claim 7, wherein the surface roughness of the tops of the multiple projections is smaller than the surface roughness of the bottoms of the multiple projections. 9. The knurl according to claim 7, wherein the distance between adjacent protrusions is longer than 5 [mu]m and shorter than 50 [mu]m. 10. The ratio h/p is larger than 0.05 and smaller than 0.3, where h is the height of the protrusions and p is the distance between adjacent protrusions. or knurling described in one item. 11. The molded resin article according to claim 7, wherein an angle formed by a normal line of the surface of the projection and a normal line of the maximum inclined portion of the projection is 10[deg.] or more. 12. The method of manufacturing a knurl according to claim 7, wherein the knurl is formed by transferring a mold processed by laser processing.

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