Manufacturing method of resin molded product, manufacturing method of electronic device

Abstract

To have enabled resin products with an outer surface that gives the observer a sense of luminosity similar to that of paints mixed with tiny glass beads or metal flakes with resin molding using a metal mold.SOLUTION: The resin molded product is characterized in that it has a plurality of convex portions formed in a predetermined area, the histogram showing the height distribution of the plurality of convex portions has two peaks with Hx as a boundary, and among the plurality of convex portions, when the convex portion whose height is less than or equal to the Hx is the first convex portion and the convex portion whose height is greater than the Hx is the second convex portion, the arithmetic average curvature for the first convex portion is smaller than the arithmetic average curvature for the second convex portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin molded article having an exterior surface with a controlled gloss due to the provision of a fine surface structure, a manufacturing method thereof, etc. In particular, the present invention relates to a resin molded article that gives an observer the impression of a texture (glossiness) with glittering dots (fine areas with high reflectivity) scattered over a matte base. [Background technology]

[0002] High design quality is required for the exterior surfaces of resin parts used in the housings and shells of various products, including electronic devices such as digital cameras and printers. For example, smoothing the surface of a part can give it a mirror-like shine, creating a lustrous aesthetic, or conversely, creating minute, invisible irregularities on the surface of a part can create a matte texture.

[0003] Painting the exterior surfaces of molded products has long been used as a method for enhancing the texture and design of the exterior surfaces of resin products. However, because painting is applied to each individual molded product, it is not always suitable for mass production in terms of uniformity, variation, labor hours, productivity, cost, etc.

[0004] Therefore, attempts have been made to improve the texture of the exterior surface by devising the molding surface of the mold used when molding resin, without relying on painting. For example, Patent Document 1 proposes a method for manufacturing a molding die for obtaining a textured product with improved design and scratch resistance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-314569 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, there has been a demand for diversity in product design, and in particular, there is a demand for shiny, luxurious exterior surfaces to enhance design. For example, a shiny surface with a matte base and scattered sparkling dots (fine areas with high reflectivity) is preferred as an exterior surface that can convey a sense of luxury in a subdued setting.

[0007] In order to impart such a lustrous appearance to the exterior surface, a method is known in which highly reflective, minute glass beads or metal flakes are mixed into paint and then applied to the exterior surface of a molded product. However, as already mentioned, the coating method is not necessarily suited to mass production in terms of uniformity, variation, man-hours, productivity, cost, and the like.

[0008] On the other hand, by using the molding die described in Patent Document 1, it is possible to produce a textured product in which finer irregularities than the embossed irregularities are arranged within the concave portions of the embossed irregularities, and smooth convex surfaces are formed in the convex portions of the embossed irregularities where the fine irregularities have been flattened.

[0009] However, the outer surface of the textured product manufactured using the mold disclosed in Patent Document 1 has a texture that is completely different from that of an outer surface coated with paint mixed with tiny glass beads or metal flakes, and does not give the observer an impression close to the brilliance that such a painted surface has.

[0010] Therefore, it was hoped that resin molding using a mold could be used to create resin products with an exterior that gives the observer a sense of brilliance similar to that achieved when painted with paint mixed with tiny glass beads or metal flakes. [Means for solving the problem]

[0011] One aspect of the present invention is a method for producing a medicament for the treatment of a pulmonary arthritis. Textured surface A method for manufacturing a resin molded product comprising: the textured surface has a plurality of first convex portions and a plurality of second convex portions that are taller than the plurality of first convex portions, and one second convex portion of the plurality of second convex portions is located between two first convex portions that are adjacent to the one second convex portion of the plurality of first convex portions; The aforementioned Multiple Corresponding to the first convex part Multiple First recess and before Note MultipleCorresponding to the second convex part Multiple A second recess and The molding surface is formed by laser processing. providing a mold comprising: The molding surface of Non-transparent resin Transfer to material and Do, this The manufacturing method is characterized by the above. [Effects of the Invention]

[0012] According to the present invention, it is possible to realize a resin product with an outer surface that gives the observer a sense of brilliance similar to that of a product painted with paint containing tiny glass beads or metal flakes, by resin molding using a mold. [Brief explanation of the drawings]

[0013] [Figure 1] 1A is a perspective view schematically illustrating an enlarged portion of an outer surface of a resin molded article according to an embodiment, and FIG. 1B is a cross-sectional view taken along line A1-A2. [Figure 2] 10A is a histogram showing the distribution of heights of minute convex portions provided on the outer surface of an embodiment, and FIG. 10B is a histogram in which fluctuations (high frequency components) in the frequency distribution have been removed. [Figure 3] FIG. 2 is a schematic enlarged perspective view of a base surface on which only first convex portions CV1 are provided. [Figure 4] FIG. 1 is a schematic perspective view showing an example of a resin molded product according to an embodiment. [Figure 5] 4A and 4B are diagrams showing the results of observing the outer surface of the resin molded product according to the embodiment with a laser microscope. [Figure 6] A monochrome image in which the height distribution of the convex parts is normalized and the height is converted into shades (gradations). [Figure 7] A black and white binary image in which the second convex part CV2 is shown in white and the rest of the image is shown in black. [Figure 8] 1A to 1C are diagrams for explaining a method for manufacturing a mold according to an embodiment using a laser processing machine. [Figure 9](a) Diagram showing the setup of the injection molding machine. (b) Diagram showing the mold clamping process. (c) Diagram showing the injection process. (d) Diagram showing the pressure holding and cooling processes. (e) Diagram showing the mold opening and demolding processes. [Figure 10] 1A is an external view of a camera including a resin molded product according to an embodiment, and FIG. 1B is an external view of a printer including a resin molded product according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A resin molded product, a method for manufacturing a resin molded product, a mold, a device including a resin molded product, and the like, which are embodiments of the present invention, will be described with reference to the drawings. Note that the exterior surfaces of the resin molded products in the embodiments described below are not necessarily limited to surfaces exposed on the front side of the housing, outer shell, etc. of the device. Even if a surface is not always visible to the user, for example, a surface that becomes visible when a door, hatch, or lid of the device is opened may be treated as an exterior surface. Therefore, in the following, a surface of a resin part or resin product that may be visible to the user may be referred to simply as an "exterior surface." In the drawings referred to in the following description of the embodiments, elements denoted by the same reference numerals have the same functions unless otherwise specified.

[0015] (Regarding resin molded products) Regarding a resin molded product according to an embodiment, the shape of the outer surface as a predetermined region that gives a viewer a sense of brilliance will be described. FIG. 1(a) is an enlarged perspective view of a portion of the outer surface (predetermined region) of the resin molded product according to the embodiment, and FIG. 1(b) is a cross-sectional view showing the shape of the outer surface taken along line A1-A2 in FIG. 1(a). As shown in FIGS. 1(a) and 1(b), the outer surface of the embodiment has numerous minute protrusions. FIG. 2(a) is a histogram showing the distribution of the heights of the minute protrusions provided on the outer surface of the embodiment, with the vertical axis representing the number of protrusions (frequency) and the horizontal axis representing the height of the protrusions. FIG. 2(b) is a histogram obtained by applying a low-pass filter to the graph of FIG. 2(a) to remove fluctuations (high-frequency components) in the frequency distribution.

[0016] 2(a) and 2(b), when the height distribution of the convex portions provided on the outer surface of the resin molded product of the embodiment is taken, it can be seen that two peaks are formed in the histogram. The boundary between the two peaks (the bottom of the valley separating the two peaks) is defined as height Hx, and convex portions whose height is Hx or less are collectively referred to as first convex portion CV1, and convex portions whose height exceeds Hx are collectively referred to as second convex portion CV2.

[0017] On the outer surface of the resin molded product of the embodiment, the total number N1 of first protrusions CV1 is greater than the total number N2 of second protrusions CV2. As shown in FIG. 1(a), the second protrusions CV2 are dispersed, and each second protrusion CV2 is generally surrounded by a plurality of first protrusions CV1. In terms of the arrangement density per unit area on the outer surface, the density of the first protrusions CV1 is greater than the density of the second protrusions CV2.

[0018] For ease of explanation, Figure 3 shows a schematic enlarged perspective view of the outer surface shape of a resin molded product on which only the first convex portions CV1 are laid. In the following explanation, for convenience, the outer surface on which only the first convex portions CV1 are laid, as in Figure 3, will be referred to as the base surface. The base surface is a textured surface that gives a visually matte feel. A textured surface is a surface on which a fine pattern (concave and convex) is created on the surface of a molding die (casting die or press die), and the pattern is transferred to the resin molded product; it is a matte surface that is not mirror-finished.

[0019] The outer surface of this embodiment has a shape in which second protrusions CV2, each taller than the first protrusions CV1, are scattered across the base surface. The radius of curvature of the second protrusions CV2 is smaller than that of the first protrusions CV1. Here, the radius of curvature refers to the radius of an approximate circle passing through the peaks of the protrusions, as shown in FIG. 1(b). If the radius of curvature of the second protrusions CV2 is R2 and the radius of curvature of the first protrusions CV1 is R1, then R1 > R2. The embodiment of FIG. 1(a) can also be said to have a shape in which some of the first protrusions CV1 on the base surface of FIG. 3 are replaced with second protrusions CV2, which are taller but have a smaller radius of curvature. Note that, assuming the reciprocal of the radius of curvature as the curvature, statistics of the protrusions on the outer surface reveal that the arithmetic mean curvature spc1 of the first protrusions CV1 is smaller than the arithmetic mean curvature spc2 of the second protrusions CV2, i.e., spc2 > spc1.

[0020] The resin molded product of this embodiment having such an outer surface shape gives the observer a sense of brilliance similar to that of a surface painted with paint containing minute glass beads or metal flakes. In the case of painting, highly reflective glass beads or metal flakes are dispersed in a matte paint, and the difference in reflectivity of the materials is utilized to achieve a brilliance in the form of sparkling dots (fine areas with high reflectivity) scattered on a matte base.

[0021] In contrast, the outer surface of this embodiment does not rely on the difference in reflectivity of different materials, but rather on the devised shape of the convex portions formed on the outer surface by mold molding, thereby achieving a brilliance with sparkling dots (fine areas with high reflectivity) scattered across a matte base.

[0022] Light is reflected so that the angle of incidence and the angle of reflection are the same, so the wider the angular distribution of the normal to the incident surface, such as when the incident surface is curved, the wider the angular distribution of the reflected light. For example, if light is incident on a perfectly flat surface (mirror surface) at a constant angle of incidence, the light will only be reflected in the direction of a constant reflection angle. On the other hand, if the surface is rough, the reflection angle will be distributed in various directions. In general, in interfacial reflection, the greater the angle of incidence, the greater the intensity of the reflected light. In other words, if the surface is undulating, the diffusibility of the reflected light increases and there will be angles at which the reflection intensity is strong.

[0023] A base surface on which a group of first convex portions CV1 with a relatively large radius of curvature is arranged has light scattering properties compared to a flat surface (mirror surface), resulting in a surface with a matte feel. By dispersing second convex portions CV2, which protrude higher than the first convex portions CV1 but have a smaller radius of curvature, throughout the base surface, it is possible to achieve a brilliance that resembles bright spots scattered across a matte background.

[0024] By making the base surface a textured surface with a large radius of curvature, the intensity of the specular reflection component is controlled. Furthermore, by dispersing protruding convex portions with a smaller radius of curvature than the base surface onto the base surface, the light is diffused over a wider angle than the base surface, creating bright spots with high reflection intensity within the base surface. This difference in reflection intensity and diffusion angle characteristics between the base surface and the bright spots makes it possible to achieve a brilliance in which the reflection changes depending on the viewing angle.

[0025] The shape of the outer surface of the resin molded product in the embodiment can be appropriately set according to the desired sense of brilliance, within the range that allows for good reproducibility through molding using a mold. For example, if the proportion of the area of ​​the outer surface occupied by the second convex portions CV2 is less than 5% in a planar view, the number of bright spots will be too small, resulting in weak reflection intensity and insufficient sense of brilliance. Therefore, it is preferable that the proportion of the area occupied by the second convex portions CV2 is 5% or more of the area of ​​the outer surface. On the other hand, if the proportion of the area occupied by the second convex portions CV2 is more than 40% in a planar view, the number of bright spots will be too large and the contrast difference between the base surface and the bright spots will not be sufficient. This will actually reduce the sense of brilliance perceived by the viewer, so it is preferable that the area occupied by the second convex portions CV2 is 40% or less of the area of ​​the outer surface.

[0026] Furthermore, when focusing on the area on the outer surface where only the first convex portion CV1 is formed, the surface roughness preferably has an spc value of 10 [1 / mm] or more and 30 [1 / mm] or less, and an sdr value of 0.001 or more and 0.015 or less.

[0027] Here, spc is the arithmetic mean curvature of the ridge lines passing through the vertices of each convex portion (the average value of the reciprocals of the radii of the approximation circles of the ridge lines passing through the vertices of each convex portion), and is expressed by the following mathematical formula (1). In this mathematical formula (1), x and y represent the coordinate position when the outer surface is viewed in plan, z represents the height component of the convex portion at that position, and n represents the number of vertices of the convex portion. A small value indicates a mountain shape with a gentle slope and a wide base, while a large value indicates a shape with a pointed, narrow width.

[0028]

number

[0029] If the arithmetic mean curvature spc value of the base surface is less than 10 [1 / mm], the base surface becomes nearly flat, and depending on how the light hits it, it may become like a mirror reflection. On the other hand, if the arithmetic mean curvature spc value of the base surface is greater than 30 [1 / mm], scattering and reflection intensity on the base surface increase, and it becomes difficult to obtain a sufficient contrast difference with the bright spot (second convex portion CV2), resulting in a loss of brightness.

[0030] Furthermore, sdr is the developed area ratio of the interface, and is expressed by the following formula (2). In formula (2), x and y represent the position on the coordinate system when the outer surface is viewed in a plane, z represents the height component of the convex portion at that position, and A represents the area of ​​the defined region. Therefore, the developed area ratio sdr of this interface represents how much the surface area has increased relative to the area of ​​the defined region.

[0031]

number

[0032] If the sdr value, which is the developed surface area ratio of the interface, is small, the surface is close to being flat, and if the sdr value is large, it means that there are many steep surfaces. If the sdr of the base surface is less than 0.001, the base surface becomes nearly flat, and depending on how the light hits it, it may become almost specular. On the other hand, if the sdr value of the base surface is greater than 0.015, the scattering and reflection intensity on the base surface increases, making it impossible to obtain a contrast difference with the bright spot (second convex portion CV2), and therefore not achieving a sufficient sense of brilliance.

[0033] Furthermore, when the shape of the second convex portion CV2 (bright spot) is treated statistically, the spc value is preferably 15 [1 / mm] or more and 100 [1 / mm] or less, and the sdr value is preferably 0.020 or more and 0.080 or less.

[0034] If the SPC of the second convex portion CV2 (bright spot) is less than 15 [1 / mm], the reflection intensity of the bright spot decreases, resulting in a lack of contrast with the base surface and insufficient brightness. On the other hand, if the SPC of the second convex portion CV2 (bright spot) exceeds 100 [1 / mm], the scattering range of the bright spot increases, reducing its functionality as a bright spot. Furthermore, if the SDR value of the second convex portion CV2 (bright spot) is less than 0.020, the difference between the scattering at the bright spot and the scattering at the base surface becomes small, resulting in insufficient brightness. On the other hand, if the SDR value of the second convex portion CV2 (bright spot) exceeds 0.080, the diffusion and reflection intensity at the bright spot increase, but the reflection intensity becomes too high, causing the viewer to perceive the bright spot as being too grainy. This results in an appearance that is too rough, and the intended texture is not necessarily achieved.

[0035] Furthermore, it is desirable that the ratio of spc between the first convex portion CV1 (base surface) and the second convex portion CV2 (bright spot) is 1.5 or more and 10.0 or less. If it is less than 1.5, the contrast difference between the base surface and the bright spot will be small, and sufficient brightness will not be obtained. If it exceeds 10.0, each bright spot will become smaller, and the reflected light will also decrease, making it impossible for the bright spot to fully function. According to experiments by the inventors, it is particularly preferable that the ratio of spc between the first convex portion CV1 (base surface) and the second convex portion CV2 (bright spot) be in the range of 3 or more and 8 or less.

[0036] 4 is a perspective view showing the appearance of an example of a resin molded product according to an embodiment. The above-mentioned first convex portions CV1 and second convex portions CV2 are formed on a surface region 42 of a resin molded product 41 to impart a lustrous appearance. Note that, because the first convex portions CV1 and second convex portions CV2 are minute, for convenience of illustration, the surface region 42 is shown with a simple texture.

[0037] Next, the outer surface shape of the surface region 42 will be described in more detail. Figure 5 shows the results of observation of the outer surface of a resin molded product according to the embodiment using a laser microscope (Keyence VK-X Series shape analysis laser microscope). Figure 5 is a microscopic image composed of data from 24 measurements taken using a 50x microscope lens across four horizontal and six vertical columns. The histogram shown in Figure 2(a) represents the height distribution of the outer surface from which the observation results in Figure 5 were obtained. Therefore, by determining the height Hx described with reference to Figure 2(a) or Figure 2(b), the first convex portion CV1 and the second convex portion CV2 can be extracted from the image in Figure 5. Once the first convex portion CV1 and the second convex portion CV2 are extracted, the SPC and SDR for each can be calculated using the multi-file analysis application provided with the laser microscope. In the resin molded product according to the embodiment, the SPC value of the second convex portion CV2 (bright spot) was 80.2, and the SDR value was 0.045. The spc value of the first convex portion CV1 (base surface) was 12.3, and the sdr value was 0.004.

[0038] Figure 6 shows a monochrome image in which the height distribution of the numerous protrusions formed on the outer surface has been normalized and the heights converted into shades of gray (gradation) of the image; the lighter the color (the closer to white), the higher the height of the protrusions.

[0039] Figure 7 shows a black-and-white binary image in which the second convex portion CV2 is represented in white and the other portions in black. That is, the first convex portion CV1 and the second convex portion CV2 are separated using the method described with reference to Figures 2(a) and 2(b) and displayed as a black-and-white binary image. In other words, the white portions represent bright spots and the black portions represent the base surface. By calculating the area of ​​each of the black and white portions, it is possible to calculate the area occupancy of the second convex portion CV2 on the outer surface, which gives the observer a sense of brilliance, or the area ratio of the bright spots to the base surface. The area occupancy of the second convex portion CV2 (bright spots) on the outer surface was 14%.

[0040] As explained above, in the resin molded product of this embodiment, the brilliance is achieved by devising the shape of the convex portions formed on the outer surface by mold molding, rather than by using differences in the reflectivity of different materials, and by having sparkling dots (fine areas with high reflectivity) scattered across a matte base.

[0041] (About the mold) Next, a mold for forming the first protrusion CV1 and the second protrusion CV2 on the outer surface of the resin material will be specifically described. The molding surface of the mold is formed with a first recess for forming the first protrusion CV1 in the resin and a second recess for forming the second protrusion CV2 in the resin.

[0042] The mold can be made of a material suitable for transferring a fine shape to a resin with good reproducibility, such as stainless steel or aluminum. A recess (reverse mold) is formed on the molding surface of the mold to form the first convex portion CV1 and the second convex portion CV2 by transfer. While such a recess can, in principle, be formed by cutting, blasting, etching, or other processes, laser processing is particularly suitable for forming a fine recess with high precision in a short time.

[0043] 8 is a diagram illustrating a method for manufacturing a mold according to an embodiment using a laser processing machine. The laser processing machine 51 includes a laser head 53 capable of emitting a processing laser beam 52 and a processing stage 55 on which a mold block 54, which is the workpiece, can be placed. The relative positions of the laser head 53 and the mold block 54 can be changed by an X-axis movement mechanism, a Y-axis movement mechanism, and a Z-axis movement mechanism, and the processing laser beam 52 can be irradiated at any position on the mold block 54.

[0044] The laser light emitted from the laser head 53 is converged by an optical system (not shown) and collected at a predetermined focal position. Therefore, when irradiating the processing area with laser light, the movement mechanisms for each axis are driven so that the laser head 53 and the irradiated point are always maintained at a distance equal to the focal length. Furthermore, as a method for reducing the irradiation energy density in order to control the processing shape (e.g., the curvature and depth of the recess), laser irradiation may be performed while maintaining a defocused state shifted by a certain distance from the focal length.

[0045] The laser head has a built-in two-axis galvanometer scanner and an fθ lens, and by driving the galvanometer mirror, the irradiation position can be scanned at high speed. Since scanning with a galvanometer mirror can be performed faster than driving the stage, controlling the irradiation position by not only moving the stage but also using scanning with the galvanometer mirror in combination is advantageous in terms of reducing processing time.

[0046] The laser light source for laser processing can be either a CW laser that performs continuous irradiation or a pulsed laser that repeats irradiation in a short period of time. In this embodiment, a laser light source with a nanosecond pulse width is preferably used. It is desirable to use a laser light source that allows arbitrary selection of conditions such as laser irradiation intensity, pulse length, and pulse interval. For example, a nanosecond pulsed laser manufactured by AMPLITUDE SYSTEMS can be used as the laser oscillator. In this embodiment, the wavelength of the processing laser generated by the nanosecond pulsed laser oscillator is 1030 nm, the pulse width is 30 nanoseconds, and the average output is 15 W.

[0047] The irradiation conditions were set according to the shapes of the first and second recesses for transferring the first convex portion CV1 and the second convex portion CV2 to the resin material, and laser irradiation was performed to form a large number of recesses on the surface of the mold.

[0048] (Production method) Next, a method for manufacturing a resin molded product using the above-mentioned mold will be described in accordance with an embodiment. Figures 9(a) to 9(e) are schematic diagrams illustrating the manufacturing process for manufacturing a resin molded product according to an embodiment using an injection molding machine.

[0049] 9(a) is a schematic diagram showing the setup of an injection molding apparatus, in which 61 and 62 are molds, 63 is a cylindrical cylinder for injecting resin into the molds, and 64 is a part called a hopper for pouring the resin material into the cylinder 63. The molding surface of mold 61 and / or mold 62 is formed with first and second recesses for transferring the first convex portion CV1 and the second convex portion CV2 to the resin material. In this embodiment, the resin material used is polycarbonate resin (colored black) mixed with about 30% glass filler.

[0050] There is a screw (not shown) inside the cylinder 63, which is rotated by a motor 65 to send the resin material to the tip of the cylinder 63. The cylinder 63 is also equipped with a heater (not shown), and the solid resin material fed from the hopper 64 is heated to a temperature above the melting point on the way to the tip of the cylinder, melting it and storing it in the space at the tip of the cylinder 63.

[0051] Next, the mold clamping process shown in Figure 9(b) is performed. Molds 61 and 62 are aligned by a movable mechanism (not shown) and closed to form a cavity. Molds 61 and 62 are heated by a heater (not shown). Generally, a flow path for flowing high-temperature liquid is formed inside the mold, and the temperature of the mold is adjusted by controlling the flow rate and temperature of the liquid. The heating temperature of the mold in this process is called the mold temperature.

[0052] Next, the injection process shown in Figure 9(c) is carried out. The nozzle at the tip of cylinder 63 is pressed against an injection hole provided in mold 62. Motor 65 then operates to rotate a screw (not shown), thereby injecting molten resin 66 into the cavity formed by molds 61 and 62. The temperature of the molten resin in this process is referred to as the resin temperature.

[0053] Next, the dwelling and cooling processes shown in Figure 9(d) are carried out. In the dwelling process, the pressure applied to the molten resin 66 injected into the cavity is maintained at a predetermined level by controlling the hydraulic pressure inside the cylinder 63. This predetermined pressure is called the dwelling pressure. The dwelling pressure is selected so that the molten resin 66 reaches every corner of the space inside the cavity. In other words, an appropriate dwelling pressure is applied to the molten resin so that the resin fills the irregularities on the molding surface of the mold without any gaps and the first convex portion CV1 and the second convex portion CV2 are formed with high shape precision.

[0054] In the cooling process following the pressure holding process, with the molds 61 and 62 in the arrangement shown in Fig. 9(d), they are cooled by a cooling mechanism (not shown), and the resin inside the cavity is cooled below the glass transition temperature and solidified. As the cooling mechanism, for example, a method can be used in which a refrigerant flow path is arranged around the mold and the refrigerant is circulated to cool the mold.

[0055] When the resin in the cavity has solidified, the mold opening process and the mold release process shown in Fig. 9(e) are performed. First, in the mold opening process, the mold 61 and / or the mold 62 are moved by a drive mechanism (not shown) to separate the two. In the subsequent mold release process, for example, by protruding an ejector pin (not shown), the resin molded product 67 adhering to one mold is peeled off from the mold and taken out. Incidentally, if necessary, the gate marks (burrs left at the injection gate position) formed on the taken-out resin molded product 67 may be removed.

[0056] By the manufacturing method described above, in the present embodiment, a resin molded product in which the first convex portion CV1 and the second convex portion CV2 are formed with high shape accuracy on the outer surface can be manufactured.

[0057] [Other Embodiments] Note that the present invention is not limited to the embodiments described above, and many modifications and combinations are possible within the technical idea of the present invention.

[0058] For example, the first convex portion CV1 and the second convex portion CV2 can be formed not only by the injection molding method described above but also by various transfer molding methods that transfer the shape of the mold surface to the resin material. For example, the first convex portion CV1 and the second convex portion CV2 can be formed on the resin by an appropriate transfer method such as roll molding or press molding.

[0059] Also, the resin molded product according to the embodiment is not limited to the example shown in Fig. 4. According to the present invention, a brilliant feeling can be imparted to resin molded products having various forms and functions. For example, a glossy finish can be imparted to the surfaces of the exterior parts 121 of the camera body and the exterior parts 122 of the lens barrel of the camera shown in FIG. 10(a). Alternatively, a glossy finish can be imparted to the surfaces of the exterior parts 131 of the top panel and the exterior parts 132 of the side of the printer shown in FIG. 10(b). The camera is not limited to the example shown in FIG. 10(a) and may be an interchangeable lens single-lens reflex camera, a mirrorless camera, a compact camera, or a smartphone with a photography function. The printer is not limited to the example shown in FIG. 10(b) and may be applied to various forms such as a dedicated printer, a copier, or a multifunction printer with a reading function, and the recording method is not particularly limited, including electrophotographic, inkjet, and thermal transfer.

[0060] Furthermore, the present invention is not limited to resin molded products such as cameras and printers, but can also be applied to resin molded products for which it is desired to make the observer perceive a sense of brilliance, such as interior parts of automobiles and outer boxes for cosmetics. The resin molded product may be in the form of a thin flat plate such as a sheet or film, or may have a three-dimensional shape with a curved surface, or may be flexible.

[0061] The resin material used for the resin molded product may preferably be, but is not limited to, a thermoplastic resin such as polyethylene, polystyrene, polypropylene, polyvinyl chloride, polyester, polyamide, or polycarbonate. Since the surface reflection is utilized to impart a lustrous appearance, it is preferable to use an opaque resin material, but the color is not limited thereto. By adding an appropriate pigment or the like to the resin material, any color can be achieved. Furthermore, this method may be applied to high-strength resins containing glass fillers or carbon fillers, or functional resins such as conductive resins. [Explanation of symbols]

[0062] 41···Resin molded product / 42···Surface area / 51···Laser processing machine / 52···Laser beam / 53···Laser head / 54···Mold block / 55···Processing stage / 61, 62···Mold / 63···Cylinder / 64···Hopper / 65···Motor / 66···Molten resin / 67···Resin molded product / CV1···First convex part / CV2···Second convex part

Claims

1. A method for manufacturing a resin molded product having a textured surface, comprising: the textured surface has a plurality of first convex portions and a plurality of second convex portions each having a height greater than that of the plurality of first convex portions, and one second convex portion of the plurality of second convex portions is located between two first convex portions adjacent to the one second convex portion of the plurality of first convex portions; preparing a mold having a molding surface on which a plurality of first recesses corresponding to the plurality of first protrusions and a plurality of second recesses corresponding to the plurality of second protrusions are formed by laser processing; and transferring the molding surface of the mold to a non-transparent resin material. A manufacturing method characterized by:

2. The transfer is performed by an injection molding method. The method according to claim 1 .

3. A method for manufacturing a resin molded product having a textured surface, comprising: the textured surface has a plurality of first convex portions and a plurality of second convex portions each having a height greater than that of the plurality of first convex portions, and one second convex portion of the plurality of second convex portions is located between two first convex portions adjacent to the one second convex portion of the plurality of first convex portions; preparing a mold having a molding surface on which a plurality of first recesses corresponding to the plurality of first protrusions and a plurality of second recesses corresponding to the plurality of second protrusions are formed; and transferring the molding surface of the mold to an opaque resin material by injection molding. A manufacturing method characterized by:

4. The resin material is colored black. The method according to any one of claims 1 to 3.

5. The resin material contains a pigment. The method according to any one of claims 1 to 4.

6. The resin material contains a glass filler. The method according to any one of claims 1 to 5.

7. The main component of the resin material is a thermoplastic resin. The method according to any one of claims 1 to 6.

8. The main component of the resin material is polycarbonate. The method according to any one of claims 1 to 7.

9. The plurality of first recesses and the plurality of second recesses are formed by processing stainless steel. The method according to any one of claims 1 to 8.

10. forming the molding surface of the mold by irradiating a material of the mold with a laser under irradiation conditions of a laser processing machine according to the shapes of the plurality of first recesses and the plurality of second recesses; The method according to any one of claims 1 to 9.

11. an arithmetic mean curvature of the plurality of first convex portions on the textured surface of the resin molded product molded in the molding step is smaller than an arithmetic mean curvature of the plurality of second convex portions; The method according to any one of claims 1 to 10.

12. an arrangement density of the plurality of first protrusions on the textured surface of the resin molded product molded in the molding step is greater than an arrangement density of the plurality of second protrusions; The method according to any one of claims 1 to 11.

13. an area occupied by the plurality of first protrusions on the textured surface of the resin molded product molded in the molding step is larger than an area occupied by the plurality of second protrusions; The method according to any one of claims 1 to 12.

14. an area occupied by the plurality of second protrusions on the textured surface of the resin molded product molded in the molding step is 5% or more and 40% or less; The method according to any one of claims 1 to 13.

15. an arithmetic mean curvature of the plurality of first convex portions on the textured surface of the resin molded product molded in the molding step is 10 [1 / mm] or more and 30 [1 / mm] or less; The method according to any one of claims 1 to 14.

16. an arithmetic mean curvature of the plurality of second convex portions on the textured surface of the resin molded product molded in the molding step is 15 [1 / mm] or more and 100 [1 / mm] or less; The method according to any one of claims 1 to 15.

17. a ratio of an arithmetic mean curvature of the plurality of second convex portions to an arithmetic mean curvature of the plurality of first convex portions on the textured surface of the resin molded product molded in the molding step is 1.5 or more and 10.0 or less; 17. The method of claim 1.

18. an SDR value, which is a developed area ratio of the interface between the plurality of first convex portions on the textured surface of the resin molded product molded in the molding step, is 0.001 or more and 0.015 or less; 18. The method of claim 1.

19. an SDR value, which is a developed area ratio of the interface between the plurality of second convex portions on the textured surface of the resin molded product molded in the molding step, is 0.020 or more and 0.080 or less; 19. The method of claim 1.

20. A method for manufacturing an electronic device, comprising: The resin molded product manufactured by the manufacturing method according to any one of claims 1 to 19 is provided so that the textured surface becomes an exterior surface of the electronic device. A manufacturing method characterized by:

21. The electronic device is a camera, a camera body, a lens barrel, or a printer.

21. The method of claim 20.

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