Resin moldings and knurling

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]

[0001] The present invention relates to a molded resin article and knurling having a rubber-like, ultra-low gloss surface. [Background technology]

[0002] To improve the appearance quality of plastic products, such as their design and texture, by molding alone without painting, a process called texturing is sometimes applied to the mold. There are many types of texturing, including one that imparts a matte finish with reduced gloss. This is typically achieved by creating fine irregularities on the mold surface using etching or blasting. This transfers the fine irregularities to the molded product surface, which scatters reflected light in various directions, resulting in a matte finish (low gloss). However, matte molded product surfaces have the disadvantage of being easily scratched when rubbed with a hard object during handling. This occurs when an object harder than the resin touches the molded product, causing stress to concentrate on the convex parts of the surface irregularities, resulting in deformation. This causes the degree of light scattering to differ from that of the surrounding area, resulting in a perceived scratch. Techniques disclosed in Patent Documents 1 and 2, for example, can be used to address this drawback. According to the technology of Patent Document 1, when the surface comes into contact with a hard object, the protruding parts come into contact first, and the roughened parts located in the relatively lower parts are protected, making it less likely to be scratched. Also, Patent Document 2 discloses that scratches on the surface of a molded product are made less noticeable by making the uneven shape of the mold surface shallower through post-processing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 9-239739 [Patent Document 2] JP 8-332639 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even with conventional techniques, it is difficult to obtain a rubber-like ultra-low gloss surface, and there is a need to further reduce the visibility of scratches. [Means for solving the problem]

[0005] The present invention relates to a resin molded product characterized in that a large number of protrusions are arranged in a honeycomb pattern on the exterior surface.

[0006] The present invention is also characterized in that a knurling made of resin has a plurality of protrusions arranged in an aligned manner, and a large number of convex portions are arranged in a honeycomb pattern on the surface of the plurality of protrusions. [Effects of the Invention]

[0007] According to the resin molded article of the present invention, it is possible to obtain a molded article that has an ultra-low gloss surface like rubber, even though it is made of resin, and that is characterized by being scratch-resistant. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a first embodiment; [Figure 2] 1 is a diagram illustrating a first embodiment; [Figure 3] 10A and 10B are diagrams illustrating other embodiments. [Figure 4] 10A and 10B are diagrams illustrating other embodiments. [Figure 5] 10A and 10B are diagrams illustrating other embodiments. [Figure 6] 1 is a diagram illustrating a first embodiment; [Figure 7] 1 is a diagram illustrating a first embodiment; [Figure 8] 1 is a diagram illustrating a first embodiment; [Figure 9] Diagram showing reflection of incident light on a flat area [Figure 10] 1 is a diagram illustrating a first embodiment; [Figure 11] 10A and 10B are diagrams illustrating other embodiments. [Figure 12]FIG. 10 is a diagram illustrating a second embodiment. [Figure 13] 10A and 10B are diagrams illustrating other embodiments. [Figure 14] 1 is a diagram illustrating a first embodiment; [Figure 15] 1 is a diagram illustrating a first embodiment; [Figure 16] 1 is a diagram illustrating a first embodiment; [Figure 17] Observation of the surface of Example 1 [Figure 18] Observation of the surface of Example 2 [Figure 19] Observation of the surface of Example 3 [Figure 20] FIG. 10 is a diagram illustrating a second embodiment. [Figure 21] FIG. 10 is a diagram illustrating a second embodiment. [Figure 22] FIG. 10 is a diagram illustrating a second embodiment. [Figure 23] FIG. 10 is a diagram illustrating a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) FIG. 1 is a diagram illustrating the characteristics of the external surface shape (surface shape) of a resin molded product of the present invention, and is a conceptual diagram showing an enlarged portion of the surface. This diagram is depicted as if viewed obliquely from the surface of the resin molded product. In FIG. 1, 1 denotes the surface of the molded product. 4 denotes a plane parallel to the average plane of the molded product surface, and 5 denotes the average normal direction. A characteristic of the resin molded product of the present invention is that the protrusions 2 are densely arranged. By densely arranged, it is preferable that they are arranged in a honeycomb pattern. In the present invention, a honeycomb arrangement refers to a state in which one protrusion 17 is surrounded by six protrusions (171-176), as shown in FIG. 10. Furthermore, it is more preferable that six adjacent protrusions (171-176) surround one protrusion 17 at equal intervals. In other words, it is more preferable that the distances (L1-L6) between the vertex (P1) of the protrusion 17 in FIG. 10 and the vertices (P2, P3, P4, P5, P6, P7) of the six adjacent protrusions are the same length. In the present invention, "equally spaced" may include a certain degree of error, and the distances (L1 to L6) are considered to be equally spaced even if they include an error of ±10 μm or less.

[0010] The honeycomb arrangement allows for a high and uniform density of protrusions per unit area, which disperses the stress that occurs when the surface comes into contact with a fingernail or other object, making it less likely to deform.

[0011] The convex portions are preferably hemispherical, with the width narrowing toward the apex. When the height of a convex portion, h, is divided by the distance p between adjacent convex portions, the value h / p, it has been found that the glossiness decreases as the height of the convex portion increases and the h / p value increases. Glossiness can be measured using a standard glossmeter. For example, a glossmeter IQ FLEX60 from PHOPOINT Instruments can be used. According to the inventors' measurements, a glossiness of 3 or less is preferred to achieve a rubber-like appearance. An h / p value of approximately 0.07 or more results in a good appearance, while an h / p value of 0.05 or more approaches a rubber-like appearance. However, a larger h / p value tends to make the surface more susceptible to scratches, and a value exceeding 0.3 significantly reduces scratch resistance. That is, the h / p value is preferably 0.05 or more and 0.30 or less. Even more preferably, it is 0.06 or more and 0.20 or less, and even more preferably, it is 0.07 or more and 0.10 or less.

[0012] Furthermore, in the resin molded product of the present invention, the distance between adjacent convex portions (L1 to L6) is preferably longer than 5 μm and shorter than 100 μm. If the distance is longer than 100 μm, the uneven shape of the molded product surface may be discernible, resulting in a rough texture. On the other hand, if the distance is shorter than 100 μm, the uneven shape is indistinguishable to a person with normal eyesight, and the texture is perceived as being equivalent to the matte finish produced by blasting or etching. Furthermore, from the perspective of scratch resistance, a short distance between the apexes of the convex portions is advantageous. A short distance between the apexes of the convex portions increases the density of the convex portions per unit area, and the number of convex portions that come into contact simultaneously increases, thereby reducing the stress generated by each convex portion and improving scratch resistance. For these reasons, the distance between the apexes of the convex portions is preferably shorter than 100 μm. Furthermore, it is even more preferable that the distance be shorter than 50 μm. When a molded product is observed outdoors on a sunny day while exposed to sunlight, or indoors while exposed to a strong spotlight, it may appear to have a rough texture even if the peak-to-peak distance is less than 100 μm. Even under these special observation conditions, the texture improves when the peak-to-peak distance is less than 50 μm.

[0013] Furthermore, when considering contact with a human nail, it is necessary to consider the possibility of surface damage due to engagement with the unevenness of the nail surface. According to the inventors' observations, the nail surface has minute irregularities of several micrometers or less. If the molded product surface has irregularities of a similar size to these irregularities, the nail and the molded product will be more susceptible to damage due to their interlocking. For this reason, it is desirable that the areas near the apexes of the convex portions, which are likely to come into contact with the nail, be smooth and free of minute irregularities. Furthermore, the distance between the apexes of the convex portions is desired to be several micrometers or more, preferably 5 μm or more. On the other hand, areas away from the apexes of the convex portions, which are less likely to come into contact with the nail, do not necessarily need to be smooth. Figure 11 shows another embodiment of the molded product of the present invention. This figure shows an example in which the surface 1 of the molded product is smooth near the apexes of the convex portions 2, but near the base, away from the apexes, there are even finer irregularities 18 than the convex portions. Although these minute irregularities 18 are relatively susceptible to deformation when in contact with the nail, they may be present in areas away from the apexes of the convex regions. In other words, the surface roughness of the bottom of the convex part is rougher than that of the top. Surface roughness can be measured, for example, using a laser microscope or atomic force microscope. The height of the convex part is divided in half, and five points are measured in the area higher than the halfway point including the apex and five points in the area lower than the halfway point, and the average values ​​are compared.

[0014] As shown in FIG. 1, a convex portion is defined as having a convex curvature in the direction of normal 5. The surface of the resin molded product of the present invention may also have a concave portion 3. A concave portion is defined as a portion located between convex portions, including the apexes of adjacent convex portions, and having a concave curvature in the outward direction of the normal in a cross section perpendicular to the surface of the molded product. FIG. 2 shows the cross-sectional shape of the molded product surface shape 1 taken along line A-A' in FIG. 1. This cross-section A-A' passes through the apexes of adjacent convex portions. In FIG. 2, 5 indicates the average normal direction to the molded product surface, 2 indicates a convex portion, and 3 indicates a concave portion. The surface of the molded product of the present invention can also have a cross-sectional shape as shown in FIG. 3. FIG. 3 shows another embodiment of the cross-section A-A' in FIG. 1. In the shape shown in FIG. 3, the concave portion 3 in FIG. 2 is almost absent, and the surface of the molded product is almost entirely covered with convex portions 2. FIG. 4 shows another example of the resin molded product of the present invention. FIG. 4 shows another embodiment of the A-A' cross-section in FIG. 1. This cross-section A-A' also passes through the apexes of adjacent convex regions. In Figure 4, 5 indicates the average normal direction of the molded product surface, 2 indicates a convex portion, and 3 indicates a concave portion. A characteristic of this figure is the presence of a bending point 6 between a convex portion 2 and a concave portion 3. As shown, the resin molded product of the present invention may have a bending point between a convex portion and a concave portion. The surface of the resin molded product of the present invention may be covered almost entirely with convex portions 2, as shown in Figures 2 to 4, or may have concave portions 3 in addition to the convex portions 2. Furthermore, a characteristic of the resin molded product of the present invention is that at least the areas near the tops of the convex portions are smooth. While a matte finish is usually achieved by imparting a fine, irregularly textured structure, the present invention makes it possible to reproduce a matte finish similar to that of an irregularly textured structure by using a periodic structure with a smooth top edge. The principle behind this is explained below.

[0015] Figure 5 is an enlarged view of a portion of Figure 2, showing the reflection of incident light from a convex portion. In this figure, 2 represents a convex portion and 3 represents a concave portion. The arrow 7 represents incident light, and all five arrows represent parallel light incident on convex portion 2. On the other hand, the arrow 8 represents reflected light. Because the inclination of the surface of convex portion 2 varies depending on the location, even if the incident light is parallel, the reflected light will be directed in various directions. Figure 6 is an enlarged view of a portion of Figure 2, similar to Figure 5, showing the reflection of incident light from a concave portion. In this figure, 2 represents a convex portion and 3 represents a concave portion. The arrow 7 represents incident light, and all five arrows represent parallel light incident on concave portion 3. The arrow 8 represents reflected light. Because the inclination of the surface of concave portion 3 varies depending on the location, even if the incident light is parallel, the reflected light will be directed in various directions, just like in the case of a convex portion. As shown in Figures 5 and 6, both convex portions and concave portions have the effect of reflecting light in various directions.

[0016] Figure 7 shows how a plate-shaped resin molded product is observed using a light source. 9 is a resin molded product of the present invention, and its surface, 10, has the shape shown in Figures 5 and 6. 13 represents the observer. 11 is the light source, and 7 represents the light beams emitted from light source 11 in various directions that are incident on a certain area of ​​the resin surface. This incident light, 7, is reflected in various directions for the reasons explained in Figures 5 and 6. The arrows 8 represent reflected light, showing how it travels in various directions. 12 represents the angle at which the reflected light spreads. A molded product surface with a small angle has high gloss. On the other hand, if this angle is sufficiently large, the gloss level decreases, resulting in a rubber-like, ultra-low gloss texture. Figure 8, like Figures 5 and 6, is an enlarged view of a portion of Figure 2, with 2 representing one of the convex portions. 5 represents the normal direction to the surface of this molded product. 14 is the normal to the most inclined point of the convex portion. Reference numeral 15 denotes the angle between the normal direction 5 of the molded article surface and the normal line 14 of the most inclined portion. Experiments by the inventors have shown that when angle 15 exceeds 10°, angle 12 in FIG. 7 widens sufficiently to achieve a matte finish. In this specification, the normal direction to the molded article surface is defined as the perpendicular line to an imaginary plane connecting the peaks. That is, a 5 mm cross section of the molded article is cut out so as to include the peaks (cross section AA' in FIG. 1), and the line perpendicularly intersecting the line connecting the peaks is defined as the normal direction to the molded article surface. Furthermore, the normal to the most inclined portion of a convex portion (maximum inclination portion) is defined as the average of the normal lines obtained by cutting out a 5 mm cross section of the molded article so as to include the peaks (cross section AA' in FIG. 1), determining the most inclined point (maximum inclination portion) for each convex portion.

[0017] As mentioned above, the surface of the molded product of the present invention can be covered only with convex portions 2, as shown in Figure 1, or can have concave portions 3 in addition to convex portions 2. On the other hand, flat areas that are neither convex portions 2 nor concave portions 3 are preferably completely absent, or, if present, account for less than 10% of the surface. The reflection of incident light in such flat areas is explained using Figure 9. In Figure 9, 16 represents a flat area that is neither convex nor concave. Arrow 7 represents incident light, and all five arrows represent parallel light incident on a flat area of ​​the molded product surface. Arrow 8 represents reflected light. In this way, in flat areas, the inclination of the surface remains constant regardless of location, so incident light is reflected in approximately the same direction. If the proportion of flat areas on the molded product surface exceeds 10%, as shown in Figure 7, the proportion of light that is specularly reflected from the light source and reaches the observer increases, resulting in an increased gloss and compromising the rubber-like ultra-low gloss texture.

[0018] Next, the method for producing a resin molded article of the present invention will be described.

[0019] As an example of the method for manufacturing a resin molded product of the present invention, an example of the production of a plate-shaped resin molded product will be shown. First, a mold 24 as shown in Figure 14 is produced by cutting. A typical mold material can be used for this mold. For example, STAVAX (Uddeholm) can be used. Next, a textured shape is imparted to the surface 25 of this mold 24 by laser processing. Known laser processing techniques can be used. A short-pulse laser, such as a nanosecond, picosecond, or femtosecond laser, is preferably used. A short-pulse laser can be used to process minute hole shapes in the material surface while minimizing the thermal impact on the surrounding area of ​​the processing region. However, this is not limited to this, and other lasers may also be used.

[0020] Figure 15 shows an enlarged cross-sectional view of the processing performed on the surface of a mold using a laser processing machine. In Figure 15(a), laser light 27 is held at one point, and the irradiation point is moved so that the spacing P between dots is 100 μm or less, preferably 50 μm, and laser pulses are repeatedly emitted. This irradiation forms a depression 28 on the mold 26. Thereafter, the irradiation point is moved and laser pulses are irradiated again while the point is held. By repeating this process, a large number of fine dots can be processed. In this way, the mold shown in Figure 14 is produced.

[0021] Next, injection molding is performed using this mold. Any resin can be used as long as it can be injection molded. In the injection process, molding conditions are used that allow the shape of the mold to be sufficiently transferred, and the shape machined into the mold is transferred to the molded product, resulting in a resin molded product 29 as shown in Figure 16.

[0022] Second Embodiment FIGS. 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, in a focus ring or zoom ring of a camera lens, such as the one shown in FIG. 12 (21). 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 protrusions 34 are formed on the surface of 33. Each of the plurality of protrusions 34 has an upper surface 341 and a side surface 342, and bottom surfaces 343 are aligned and arranged between the protrusions 34. A large number of protrusions 2, as described in the first embodiment, are densely arranged on the surfaces (upper surface 341, side surface 342) of the plurality of protrusions 34 and on the bottom surfaces 343 between the protrusions 34. FIG. 23 is a diagram showing 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 a commonly used resin material such as polycarbonate. The height of the protrusions 34 is determined by the design as well as the slipperiness and feel when touched with a finger, but is generally between 0.2 mm and 1.0 mm. More preferably, it is between 0.3 mm and 0.6 mm. The height of the protrusions 34 is defined as the length of a perpendicular line extending from an imaginary plane connecting the apexes of the numerous protrusions 2 formed on the top surface 341 to the apex of one of the numerous protrusions 2 formed on the bottom surface 343.

[0023] The resin molded products shown in Figures 22(a) and (b) have a cylindrical shape, and can be manufactured using, for example, the mold shown in Figure 20. In Figure 22(a) and (b), reference numeral 24 denotes the inner mold. On the other hand, the outer mold can be divided into six sections, as shown in Figures 25-30, and can be opened and closed by sliding. To create a shape commonly known as a knurled pattern on the surface of the cylindrical molded product, the outer mold is machined by cutting a concave-convex shape corresponding to the knurled pattern, such as the surface indicated by 31 on mold 25. Next, the mold surface is laser-machined, as in the first embodiment. Figure 21 shows this process. First, as shown in Figure 21(a), laser beam 27 can be irradiated from the normal direction of the machined surface onto the bottom of the concave-convex pattern of mold 32. Next, as shown in Figure 21(b), laser beam 27 can be irradiated from the normal direction of the machined surface onto the connecting inclined surfaces.

[0024] Next, as shown in Figure 21(c), the direction is adjusted so that the laser is irradiated from the normal direction of the processing surface onto the top of the connected uneven shapes, and then processing is performed by adjusting the direction so that the laser is irradiated from the normal direction of the processing surface onto the connected inclined surfaces, as shown in Figure 21(d).

[0025] Subsequently, the knurling of the present invention can be manufactured by performing injection molding using these molds.

[0026] (Other embodiments) Figure 13 shows another example of a resin molded product to which the present invention can be applied. Examples include exterior parts 22 for the top panel of a printer and exterior parts 23 for the sides. The present invention is not limited to the resin molded products of cameras and printers shown here, but can also be applied to resin molded products for other products. [Example]

[0027] In this example, a plate-shaped resin molded product with a matte texture was produced. First, a mold 24 as shown in Figure 14 was produced by cutting. STAVAX (Uddeholm) was used as the material for this mold. Next, a concave-convex shape was created on the surface 25 of this mold 24 using a laser processing device. The laser processing device used was an LP400U (GF Machining Solutions). The wavelength of the laser used was 1064 nm. This laser was a nanosecond pulse laser, which allows for fine shape processing while minimizing thermal impact on the surrounding area of ​​the processing. The laser irradiation conditions were a pulse width of 4 ns, an output of 30%, and a frequency of 750 kHz.

[0028] Figure 15 shows an enlarged cross-sectional view of the processing performed on the surface of a mold using a laser processing machine. In Figure 15(a), laser light 27 is held at one point, and laser pulses are repeatedly irradiated under the conditions described above during that time. The irradiation dwell time was 10 ms. This irradiation forms a depression 28 on the mold 26. The irradiation point is then moved, and laser pulses are irradiated again while the point is held. By repeating this process, many fine dots are machined. The spacing P between dots is 50 μm. The mold shown in Figure 14 was produced in this manner.

[0029] Next, injection molding was performed using this mold. The molding machine used was a J180ELIII injection molding machine (Japan Steel Works, Ltd.). The resin used was Teijin Limited's Panlite G-3430R, a black-colored polycarbonate material containing approximately 30% glass filler. In the injection process, molding conditions were used that ensured sufficient transfer of the mold shape, and the shape machined into the mold was transferred to the molded product, resulting in the production of a resin molded product 29 as shown in Figure 16.

[0030] Figure 17 shows the surface of the resin molded product produced in this example, as observed with an electron microscope. Shape measurement using a laser microscope confirmed that the inclination angle of the convex regions was 10° or greater. Visual observation of the surface texture of the resin molded product produced in this example confirmed that the individual irregularities on the surface were difficult to distinguish, resulting in a smooth surface with a matte finish with a low gloss value. Next, a scratch test was conducted on the molded product. The scratch test involved pressing a fingernail against the test piece with a load of 100 gf and moving it over a distance of 30 mm in one second. The surface was then observed and evaluated based on the degree of any remaining marks. No noticeable marks were observed on the surface. [Example]

[0031] A mold was prepared and a plate-shaped resin molded product was produced in the same manner as in Example 1, except for the laser irradiation conditions. STAVAX (Uddeholm) was used as the mold material. The laser irradiation conditions were a pulse width of 4 ns, an output of 30%, a frequency of 750 kHz, and a dwell time of 5 ms during dot processing. The spacing between dots was 50 μm.

[0032] Figure 18 shows the surface of the resin molded product produced in this example, as observed with an electron microscope. Shape measurement using a laser microscope confirmed that the inclination angle of the convex regions was 10° or greater. Visual observation of the surface texture of the resin molded product produced in this example confirmed that the individual irregularities on the surface were difficult to distinguish, resulting in a smooth surface with a matte finish with a low gloss value. Next, a scratch test was conducted on the molded product. The scratch test involved pressing a fingernail against the test piece with a load of 100 gf and moving it over a distance of 30 mm in one second. The surface was then observed and evaluated based on the degree of any remaining marks. No significant marks were observed on the surface. [Example]

[0033] A mold was prepared and a plate-shaped resin molded product was produced in the same manner as in Example 1, except for the laser irradiation conditions. SUS420J2 was used as the mold material. The laser irradiation conditions were a pulse width of 4 ns, an output of 30%, a frequency of 750 kHz, and a dwell time of 5 ms during dot processing. The spacing between dots was 50 μm.

[0034] Figure 19 shows the surface of the resin molded product produced in this example, observed with an electron microscope. Shape measurement using a laser microscope confirmed that the inclination angle of the convex regions was 10° or greater. Visual observation of the surface texture of the resin molded product produced in this example confirmed that the surface irregularities were so small that they were difficult to distinguish individually, resulting in a smooth surface with a matte texture with a low gloss value.

[0035] Next, a scratch test was conducted on the molded product. In the scratch test, a fingernail was pressed against the test piece with a load of 100 gf and moved over a distance of 30 mm in one second, after which the surface was observed and judged based on the degree of marks remaining. As a result, no noticeable marks were found on the surface. [Example]

[0036] A molded product suitable for use as a focus ring or zoom ring for a camera lens, as shown in Figure 12 (21), was produced. Since the molded product in this case had a cylindrical shape, a mold as shown in Figure 20 was prepared. In this figure, 24 is the inner mold. The outer mold, on the other hand, was divided into six sections, as shown in Figures 25-30, and was designed to be openable and closable by sliding. STAVAX (Uddeholm) was used as the mold material. To create a knurled shape on the surface of the cylindrical molded product, the outer mold was machined to have a concave-convex shape corresponding to the knurled shape, as shown in Figure 25 (31). Next, the mold surface was laser-machined under the same conditions as in Example 1. Figure 21 shows the process. First, as shown in Figure 21 (a), the laser 27 was irradiated from the normal direction to the machined surface onto the bottom of the concave-convex shape of mold 32. Next, as shown in Figure 21 (b), the laser was irradiated from the normal direction to the machined surface onto the connecting inclined surface, as shown in Figure 21 (b).

[0037] Next, as shown in (c), the direction of the laser was adjusted so that it was irradiated from the normal direction of the processing surface onto the top of the connected uneven shapes, and then, as shown in (d), the direction of the laser was adjusted so that it was irradiated from the normal direction of the processing surface onto the connected inclined surfaces.

[0038] Next, injection molding was performed using these molds. The molding machine used was a J180ELIII injection molding machine (Japan Steel Works, Ltd.). The resin used was Teijin Limited's Panlite G-3430R, a black-colored polycarbonate material containing approximately 30% glass filler. In the injection process, molding conditions were used that ensured sufficient transfer of the mold shape, and the shape machined into the mold was transferred to the molded product, resulting in a resin molded product 33 as shown in Figure 22(a). Figure 22(b) is an enlarged view of area B in (a).

[0039] Figure 23 shows the surface of the resin molded product produced in this example, as observed with an electron microscope. Shape measurement using a laser microscope confirmed that the inclination angle of the convex regions was 10° or greater. Visual observation of the surface texture of the resin molded product produced in this example revealed that the individual irregularities on the surface were difficult to distinguish, resulting in a smooth, matte surface with a low gloss value, similar in appearance to a rubber part. Next, a scratch test was conducted on the molded product. The scratch test involved pressing a fingernail against the test piece with a load of 100 gf and moving it 30 mm over one second. The surface was then observed and evaluated based on the degree of any remaining marks. No significant marks were observed on the surface. [Explanation of symbols]

[0040] 1. Surface of molded product 2 Convex part 3 recess

Claims

1. A resin molded product characterized in that a large number of protrusions are arranged in a honeycomb pattern on an exterior surface, the distance between adjacent protrusions among the large number of protrusions is longer than 5 μm and shorter than 100 μm, and the angle between the normal to the exterior surface and the normal to the maximum inclination part of the protrusions is 10° or more.

2. A resin molded product characterized in that a large number of convex portions are arranged in a honeycomb pattern on the exterior surface, the distance between adjacent convex portions among the large number of convex portions is longer than 5 μm and shorter than 100 μm, and the surface roughness of the tops of the large number of convex portions is smaller than the surface roughness of the bottoms of the large number of convex portions.

3. A resin molded product that is a knurled product with multiple protrusions formed on its exterior surface, characterized in that numerous convex portions are arranged in a honeycomb pattern on the surface of the multiple protrusions.

4. 4. The resin molded product according to claim 3, wherein the surface roughness of the tops of the numerous projections is smaller than the surface roughness of the bottoms of the numerous projections.

5. 5. The resin molded product according to claim 3, wherein an angle between a normal to the surface of the protrusion and a normal to the maximum inclination portion of the convex portion is 10 degrees or more.

6. 6. The resin molded product according to claim 1, wherein the distance between adjacent convex portions among the large number of convex portions is longer than 5 [mu]m and shorter than 50 [mu]m.

7. 7. The resin molded product according to claim 1, wherein h / p is greater than 0.05 and smaller than 0.3, where h is the height of the convex portion and p is the distance between adjacent convex portions among the plurality of convex portions.

8. 5. The resin molded product according to claim 2, wherein an angle between a normal to the outer surface and a normal to the maximum inclination portion of the convex portion is 10 degrees or more.

9. A method for producing a resin molded product, comprising: molding the resin molded product according to any one of claims 1 to 8 by transferring a mold processed by laser processing.

10. A camera lens comprising a resin molded product described in any one of claims 1 to 8.

11. A camera equipped with a resin molded product described in any one of claims 1 to 8.

12. A printer equipped with a resin molded product described in any one of claims 1 to 8.

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