Resin molded article and method for producing same, as well as composite molded article and method for producing same

Abstract

Provided are a resin molded article capable of further enhancing strength when joined to another molded article, and a method for producing the same, as well as a composite molded article and a method for producing the same. The present invention provides a resin molded article and a method for producing the same, as well as a composite molded article and a method for producing the same, the resin molded article including carbon fibers 12 and a resin 11, wherein a groove 13 having a bottom portion 13b and a pair of opposing wall portions 13a is formed on one surface 10s, and the wall portions 13a of the groove 13 do not have the carbon fibers 12 exposed and have irregularities.

Description

Resin Molded Product, Method for Producing the Same, Composite Molded Product, and Method for Producing the Same

[0001] The present invention relates to a resin molded product, a method for producing the same, a composite molded product, and a method for producing the same.

[0002] In recent years, in fields such as automobiles, electrical products, and industrial equipment, in order to meet the demands for reducing carbon dioxide emissions and manufacturing costs, the movement to replace some metal molded products with resin molded products has been spreading. Along with this, composite molded products that integrate resin molded products and metal molded products have become widely popular. This is not limited to this, and composite molded products that integrate molded products made of the same or different materials have also become widely popular.

[0003] As a method for producing a composite molded product in which one molded product and another molded product are integrated, for example, the following have been proposed. In Patent Document 1, a filler such as glass fiber is mixed into one resin and molded, and the surface for adhering the other resin is treated with chemicals, plasma, flame, etc. to remove resin with a thickness of 0. several μm to several 10 μm, and then the other resin is filled, molded, and adhered in contact with the surface for adhering the other resin. In Patent Document 2, it has been proposed to form a nanostructure on the surface of one resin molded product by irradiating electromagnetic radiation, and then fill, mold, and integrate the other resin molded product in contact with the surface.

[0004] In addition, in Patent Document 3, it has been proposed to press-join a base material having an uneven shape and hard fibers protruding on the surface and a skin material. In Patent Document 4, it has been proposed to join molded members having metal fibers exposed on the surface at the joint.

[0005] Japanese Patent Application Laid-Open No. 01-126339, Japanese Patent Publication No. 2011-529404, Japanese Patent Application Laid-Open No. 2000-351189, Japanese Patent Application Laid-Open No. 3-203291, Japanese Patent Application Laid-Open No. 2021-120194, International Publication No. 2014 / 125999

[0006] However, there is room for further improvement regarding the strength when one molded product is joined to another. For example, in the method described in Patent Document 3, the composite molded product is formed by compression molding a surface material onto a base material on which fibers protrude from the surface of the molded product having irregularities. This makes it easy not only to pierce the fibers into the surface material, but also to pull the surface material away from the fibers. To prevent the surface material from coming off, it is necessary to join the base material and the surface material with an adhesive.

[0007] Furthermore, the problem addressed in Patent Document 4 is to ensure electrical conductivity between the surfaces of both molded members, and it is sufficient if an inorganic filler is applied to both molded members. Patent Document 4 does not disclose or suggest how to obtain a high anchoring effect.

[0008] The present invention was made to solve the above-mentioned problems, and its objective is to provide a resin molded article and a method for manufacturing the same that can further increase the strength when joined with other molded articles, as well as a composite molded article and a method for manufacturing the same.

[0009] The above objective is achieved by the present invention as described below. That is, the embodiments of the present invention are as follows.

[0010] [1] A resin molded product comprising carbon fibers and resin, wherein a groove is formed on the surface of 1, having a bottom portion and a pair of opposing wall portions, and the wall portions of the groove are not exposed and have an uneven surface.

[0011] [2] The resin molded article according to [1], wherein the resin is a thermoplastic resin.

[0012] [3] The resin molded article according to [1], wherein the resin is selected from at least one of the group consisting of polyetheretherketone, polyphenylene sulfide, and liquid crystal polymer.

[0013] [4] The resin molded article according to [1], wherein the groove is formed by irradiation with laser light.

[0014] [5] A composite molded product in which another molded product is integrated into the surface of the resin molded product described in [1] on which the groove is formed.

[0015] [6] The composite molded product according to [5], wherein a part of the other molded product is inserted into the groove.

[0016] [7] A method for manufacturing a resin molded product comprising a groove forming step, in which a laser beam is irradiated onto at least a portion of the surface of a resin molded product containing carbon fibers and resin, and the grooves having a bottom portion and a pair of opposing wall portions, wherein the wall portions do not expose the carbon fibers and have an uneven surface.

[0017] [8] A method for manufacturing a composite molded product, comprising: a groove forming step of irradiating at least a portion of the surface of a resin molded product containing carbon fibers and resin with laser light to form grooves having a bottom portion and a pair of opposing wall portions, wherein the wall portions do not expose the carbon fibers and have an uneven surface; and a composite molding step of integrating the grooved surface with another material as a contact surface to manufacture a composite molded product.

[0018] [9] The method for manufacturing a composite molded product according to [8], wherein the composite molding step is a step of manufacturing a composite injection molded product by injection molding in which the surface on which the groove is formed is used as a contact surface with other materials.

[0019] According to the present invention, it is possible to provide a resin molded article, a method for manufacturing the same, and a composite molded article that can further increase the strength when joined with other molded articles.

[0020] This is a schematic enlarged cross-sectional view of a resin molded product according to an exemplary embodiment of the present invention. This is a schematic high-magnification cross-sectional view of the vicinity of the wall portion in Figure 1, further enlarged. This is a schematic enlarged cross-sectional view of the resin molded product before the laser irradiation process. This is a schematic enlarged cross-sectional view of a composite molded product according to an exemplary embodiment of the present invention. This is a schematic high-magnification cross-sectional view of the vicinity of the wall portion in Figure 3, further enlarged. This is a schematic explanatory diagram for explaining the process of manufacturing a composite molded product according to this embodiment by multi-molding. These are micrographs of the laser irradiation surfaces 10s of Example 1 (member A), Comparative Example 1 (member B), Reference Example 1 (member C), Example 2 (member D), and Example 3 (member E) after laser irradiation, taken with a scanning electron microscope (SEM) at a magnification of 200x.

[0021] Hereinafter, a resin molded article, a method for manufacturing the same, and a composite molded article according to exemplary embodiments of the present invention will be described in detail with reference to the drawings.

[0022] (Resin molded product) Figure 1 is a schematic enlarged cross-sectional view of a resin molded product 10 according to an embodiment. The resin molded product 10 includes carbon fibers and resin, and more specifically, carbon fibers 12 are dispersed and arranged in the resin 11. The surface 10s of the resin molded product 10 has a plurality of grooves 13, each having a bottom portion 13b and a pair of opposing wall portions 13a. In this embodiment, the surface 10s on which the grooves are provided is flat, but the surface is not required to be flat and may be curved or have an uneven shape.

[0023] Figure 2 is a schematic, highly magnified cross-sectional view of the vicinity of the wall portion 13a in Figure 1. As shown in Figures 1 and 2, the carbon fibers 12 are not exposed on the wall portion 13a of the groove 13. Furthermore, the wall portion 13a of the groove 13 has irregularities as shown in Figures 1 and 2. It is presumed that the structure and shape of the wall portion 13a of the groove 13 is due to the fact that the groove 13 is formed by irradiation with laser light. Further details will be described in the section on "Method for Manufacturing Resin Molded Products".

[0024] The type of resin is not particularly limited as long as it can be removed by laser irradiation and, as a result, form grooves such as groove 13. It is also acceptable as long as the absorption of the laser light can be adjusted so that not only is the resin removed by laser irradiation, but the carbon fibers 12 are also removed by laser irradiation, forming grooves 13 in which the carbon fibers 12 are not exposed from the wall portion 13a.

[0025] One method for adjusting the laser absorption rate is to adjust the type and amount of laser-absorbing compound added to the resin. Pigments and dyes are used as such compounding agents, with carbon black being particularly effective.

[0026] The resin may be thermoplastic or thermosetting, but a thermoplastic resin is preferred. Suitable resin materials include, for example, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polybutylene terephthalate (PBT), polyacetal (POM), polyether ether ketone (PEEK), and polyether ketone (PEK). Among these, at least one selected from the group consisting of PEEK, PPS, and LCP is preferred, with PEEK being the most preferred.

[0027] The carbon fiber 12 is a filler material for reinforcing the resin, and conventionally known types and shapes can be used.

[0028] In this embodiment, the groove 13 has a rectangular cross-section, as shown in Figure 1, that is, the bottom portion 13b and the pair of wall portions 13a are substantially perpendicular to each other. However, the groove shape is not limited to a rectangular cross-section. In fact, the groove 13 formed by laser irradiation has a shape in which the width gradually narrows in the depth direction, that is, an inverted trapezoidal cross-section (which is included in the concept of "substantially rectangular cross-section") (see Embodiment 1 in Figure 7).

[0029] There are no particular restrictions on the width, depth, and spacing of adjacent grooves 13, and they can be set appropriately according to the purpose. However, in order to maintain a high bonding strength with other materials when made into a composite molded product as described later, the width is preferably about 30 μm to 200 μm, and more preferably about 50 μm to 120 μm. As for the depth of the groove 13, a deeper groove is preferable in order to obtain a higher anchoring effect. Specifically, the depth is preferably about 30 μm to 500 μm, more preferably about 50 μm to 300 μm, and more preferably about 100 μm to 200 μm.

[0030] Furthermore, the spacing between adjacent grooves is preferably made somewhat large from the viewpoint of exhibiting an anchoring effect in order to increase the bonding strength of the composite molded body. Specifically, the spacing between adjacent grooves 13 is preferably 0.75 to 4 times the width of the groove, i.e., if the width of the groove is 200 μm, it is preferably 150 μm to 800 μm, and more preferably 1 to 2 times the width of the groove, i.e., if the width of the groove is 200 μm, it is preferably 200 μm to 400 μm.

[0031] In this embodiment, the anchoring effect is further enhanced by providing multiple grooves 13. Multiple grooves 13 may be formed by folding over adjacent grooves in a single groove, or they may be formed as multiple grooves. Multiple grooves 13 may be formed in a grid pattern where the grooves 13 intersect (see Embodiment 1 in Figure 7), or grooves 13 connected at both ends may be arranged like contour lines. Furthermore, when the grooves 13 are formed in a grid pattern, they may be diamond-shaped. In this way, by providing multiple grooves 13 and / or intersecting them, or arranging them like contour lines, the bonding strength with other materials when a composite molded product is formed, as described later, can be increased.

[0032] In this embodiment, the irregularities of the wall portion 13a of the groove 13 are not regular, nor can the degree of these irregularities be specified. However, as will be described later, it is presumed that these irregularities contribute to the bonding force with other materials when a composite molded product is formed, so it is desirable that the irregularities be of a certain size.

[0033] Specifically, a difference in height between the concave and convex areas of at least 1 μm is considered a desirable degree of unevenness on the wall portion 13a, and a difference of 3 μm to 50 μm is considered a more desirable degree. Furthermore, since unevenness is formed by the removal of carbon fibers by laser irradiation, if clear unevenness is observed on the surface of the wall portion when observed under a microscope at 200x magnification, it can be determined that the degree of unevenness on the wall portion is at least suitable for the present invention.

[0034] (Method for manufacturing resin molded products) The method for manufacturing resin molded products according to the embodiment includes a step of irradiating a laser onto at least a part of the surface (hereinafter referred to as the "laser irradiation surface") of a resin molded product containing carbon fibers and resin to form grooves (hereinafter referred to as the "laser irradiation step"). The grooves formed after the operation of the laser irradiation step have a bottom portion 13b and a wall portion 13a connecting the bottom portion 13b and the laser irradiation surface (surface) 10s, as shown in the groove 13 in Figure 1, and the wall portion 13a has no exposed carbon fibers 12 and has an uneven surface.

[0035] Figure 3 is a schematic enlarged cross-sectional view of the resin molded product (hereinafter referred to as "pre-processed molded product 10'") before the laser irradiation process. As shown in Figure 3, the pre-processed molded product 10' has carbon fibers 12 dispersed in the resin 11 and has a laser irradiation surface 10s on which grooves are provided.

[0036] In the laser irradiation process, the laser beam is irradiated perpendicular to the laser irradiation surface 10s, as shown by the arrow L in Figure 3. The carbon fibers 12 are burned and removed along with the resin 11 by the laser beam irradiation. Figure 3 shows a dashed line enclosing the area removed by the laser beam irradiation (hereinafter referred to as "area 13c"). Note that the direction of laser beam irradiation to the laser irradiation surface 10s does not necessarily have to be perpendicular; irradiation from an oblique angle is also acceptable, however, irradiation from approximately perpendicular is preferable from the viewpoint of irradiation efficiency, etc.

[0037] To form the groove 13 shown in Figure 1, the laser beam is scanned in the direction of extension of the groove 13 (in Figures 1 and 3, the front-to-back direction relative to the plane of the paper). The same location may be scanned more than once. After irradiation with the laser beam, the resin 11 and carbon fibers 12 are removed in the shape of the dashed line surrounding region 13c, so the wall portion of the formed groove (reference numeral 13a' in Figure 3) is expected to be planar.

[0038] However, as shown in Figures 1 and 2, the wall portion 13a of the groove 13 has irregularities. Specifically, the irregularities of the wall portion 13a are evident from the micrograph of Example 1 in Figure 7 of the embodiments described later. That is, the groove 13 formed by the operation of the laser irradiation process has a bottom portion 13b and a wall portion 13a connecting the bottom portion 13b and the surface 10s, and the wall portion 13a has irregularities and the carbon fibers 12 are not exposed.

[0039] The reason why irregularities are formed on the wall portion 13a by laser irradiation is not clear, but it is presumed that when the carbon fibers 12 are burned by laser irradiation, the carbon fibers 12 absorb a larger amount of energy, and this large amount of energy has an effect such as melting the surrounding resin 11, thereby roughening the surface of the wall portion 13a. Therefore, as shown in Figure 2, it is presumed that the portion of the carbon fibers 12 near the wall portion 13a is burned, and the resin 11 surrounding the area where the carbon fibers 12 were present before burning is melted, forming depressions 14, and thus irregularities are formed on the entire wall portion 13a.

[0040] Furthermore, the laser beam irradiation creates irregularities not only on the wall portion 13a but also on the bottom portion 13b, and the irregularities wrap around from the wall portion 13a to the laser irradiation surface 10s at the opening of the groove 13 (the upper end of the groove 13 in the drawing). However, the irregularities formed mainly on the wall portion 13a are expected to provide an anchoring effect that contributes to the bonding force with other molded products, as will be described later.

[0041] The laser irradiation conditions are preferably such that they are sufficient to completely burn off the resin 11 and carbon fibers 12 in the irradiated area. Therefore, the preferred conditions will vary depending on the resin material used for the resin 11. The laser irradiation conditions can be adjusted as needed, as long as the desired uneven shape is achieved.

[0042] For example, when polyether ether ketone (PEEK, melting point 341°C) is used as the resin 11, as an example of the laser light irradiation conditions for obtaining the desired uneven shape, the 3-Axis YV04 laser marker MD-X1520 manufactured by Keyence Corporation is used in the apparatus, the irradiation output of the laser light is 10%, the scanning speed is 70 mm / sec, the pulse frequency is in the range of 4 to 6 kHz, and the number of irradiation times at the same location is preferably in the range of 6 to 10 times.

[0043] (Composite molded product) FIG. 4 is a schematic enlarged cross-sectional view of a composite molded product according to an embodiment which is an exemplary aspect of the present invention. As shown in FIG. 4, the composite molded product 30 according to the present embodiment is one in which another molded product 20 is integrated with the laser irradiation surface (surface) 10s of the resin molded product 10 in which the groove 13 is formed. The resin molded product 10 used in the present embodiment is the resin molded product 10 according to the above-described embodiment described using FIG. 1.

[0044] FIG. 5 is a schematic highly enlarged cross-sectional view further enlarging the vicinity of the wall portion 13a in FIG. 4. As shown in FIG. 4, a part of the other molded product 20, that is, the protruding portion 21, enters the inside of the groove 13. As shown in FIG. 5, the protruding portion 21 that has entered the inside of the groove 13 further enters the depression 14 formed in the wall portion 13a, and the minute protrusion 24 is formed. Due to the anchor effect acting between the depression 14 of the wall portion 13a and the minute protrusion 24 of the protruding portion 21, the resin molded product 10 and the other molded product 20 are firmly joined together.

[0045] The material of the other molded product 20 is not particularly limited as long as it can enter the inside of the groove 13 in the uncured state, and it may be any of thermoplastic resins, curable resins (thermosetting resins, photocurable resins, radiation curable resins, etc.), rubber, adhesives, metals, and the like.

[0046] The composite molded product 30 according to this embodiment can be easily manufactured by multi-shot molding described later. In addition to multi-shot molding, it can also be manufactured by heating and melting other resin molded products (other molded products 20 in this embodiment) such as ultrasonic welding, laser welding, and high-frequency induction heating welding. However, for reasons such as reducing manufacturing man-hours and enabling combinations of different materials (material selection is possible according to the intended use), it is more preferable to integrate them by multi-shot molding to obtain the composite molded product 30.

[0047] In the composite molded product 30 according to this embodiment, since another resin molded product that will be the other molded product 20 can be joined to the first joining planned surface (laser irradiation surface 10s) of the resin molded product 10 in which the groove 13 has been formed in advance, a composite molded product 30 with excellent joining strength can be obtained without selecting a combination of materials of the resin molded product.

[0048] A method for manufacturing the composite molded product 30 according to this embodiment by multi-shot molding will be described. FIG. 6 is a schematic explanatory diagram for explaining the process of manufacturing the composite molded product 30 according to this embodiment by multi-shot molding. First, as shown in FIG. 6(1), a primary resin is primary molded to produce a pre-process molded product 10'. Subsequently, laser light is irradiated onto at least a part of the laser irradiation surface 10s, which is the surface of the pre-process molded product 10', and the groove 13 is formed by partially removing the resin. Thereby, as shown in FIG. 6(2), the resin molded product 10 is manufactured.

[0049] Subsequently, as shown in FIG. 6(3), the grooved resin molded product 10 is placed in a mold (not shown), and a secondary resin (an uncured product such as a heat-melted product or a product before a curing reaction of the material constituting the other molded product 20) is enclosed inside this mold with the surface having the groove 13 as the contact surface, and this material is cured. By going through the above steps, a composite molded product by multi-shot molding can be manufactured.

[0050] In the manufacture of composite molded products by multi-layer molding, the type of mold used is not particularly limited, but it is preferable to insert a resin molded product 10, which has grooves such as groove 13 formed on the laser irradiation surface 10s, into an injection molding die with the laser irradiation surface 10s as the contact surface, and to integrate the material of another molded product 20 by injection molding to obtain a composite molded product. Injection molding allows for the easy manufacture of an integrated composite molded product by injecting the other molded product 20 in an uncured state into the mold containing the resin molded product 10 under high pressure, thereby effectively filling the grooves 13.

[0051] In the embodiments described above and below, the resin molded product 10 has grooves 13 and is integrated with another molded product 20 by injection molding, but the invention is not limited to this. For example, the other molded product 20 also has grooves, and the resin molded product 10 is placed on one side of the mold and the other molded product 20 is placed on the other side of the mold so that the grooves of the resin molded product 10 and the other molded product 20 face each other. Then, an adhesive composition is placed between the resin molded product 10 and the other molded product 20 so that the adhesive composition fills the grooves 13 of the resin molded product 10 and the grooves of the other molded product 20. In this way, regardless of the type of adhesive composition, even if the adhesive composition is not suitable for interlayer bonding between the resin molded product 10 and the other molded product 20, the two can be firmly joined.

[0052] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. The following examples, comparative examples, and reference examples will be described with reference to Figures 1 to 4.

[0053] (Preparation of pre-processed molded product (resin molded product) 10') As a pre-processed molded product 10' for Example 1, a plate-shaped (100 mm × 27 mm, thickness 2 mmt) member A was manufactured by injection molding using PEEK-CF, which is a compound of carbon fibers (hereinafter referred to as "CF") (number average fiber diameter 10 μm, number average fiber length 150 μm) blended with polyetheretherketone (PEEK) at a blending ratio of 23 vol% of the total volume.

[0054] Similarly, as a pre-processed molded product 10' for Comparative Example 1, a plate-shaped member B of the same shape as described above was manufactured by injection molding using the same PEEK-only formulation as described above, without any other fibers.

[0055] Similarly, as a pre-processed molded product 10' for Reference Example 1, a plate-shaped member C of the same shape as described above was manufactured by injection molding using PEEK-GF, which is PEEK in which glass fibers (hereinafter referred to as "GF") (number average fiber diameter 10 μm) in proportion to the total volume of 18 vol% are blended with the same PEEK as described above.

[0056] Similarly, as a pre-processed molded product 10' for Example 2, a plate-shaped member D of the same shape as described above was produced by injection molding using PPS-CF, which is a compound of polyphenylene sulfide (PPS) with CF (number-average fiber diameter 10 μm, number-average fiber length 150 μm) in proportion to 23 vol% of the total volume.

[0057] Furthermore, similarly, as a pre-processed molded product 10' for Example 3, LCP-CF was used, in which CF (number-average fiber diameter 10 μm, number-average fiber length 150 μm) was blended into liquid crystal polymer (LCP) in a proportion of 24 vol% of the total volume, to produce a plate-shaped member E of the same shape as described above by injection molding.

[0058] The vol% of the filler relative to the total volume was calculated from the mass-based mixing ratio (mass%) data, assuming the specific gravities of each component were PEEK 1.3, PPS 1.35, LCP 1.41, CF 1.9, and GF 2.6. The mass-based mixing ratio is equal for the carbon fibers in members A, D, and E and the glass fibers in member B (43 mass%).

[0059] (Manufacturing of grooved resin molded products) On the surface of each of the plate-shaped members A to C, a laser irradiation device (3-Axis YV04 laser marker MD-X1520 (manufactured by Keyence Corporation)) was used to form a grid-like groove 13 in a 20 mm × 50 mm area with an output of 10% (2.5 W), a scanning speed of 70 mm / sec, a pulse frequency of 5 kHz, and 8 irradiations per location, with a laser irradiation diameter of 60 μm, a width of 50 μm, and a spacing of 300 μm (laser irradiation process).

[0060] (Confirmation of surface condition) Figure 7 shows micrographs of the laser-irradiated surfaces 10s of Example 1 (member A), Comparative Example 1 (member B), Reference Example 1 (member C), Example 2 (member D), and Example 3 (member E) after laser irradiation, taken with a scanning electron microscope (SEM) at a magnification of 200x. As can be seen from the scanning electron microscope (SEM) images in Figure 7, in Examples 1, 2, and 3, carbon fibers are not exposed from the walls of the grooves, and the walls clearly have an uneven surface.

[0061] On the other hand, as can be seen from the scanning electron microscope image in Figure 7, in Comparative Example 1, where no fibers are filled, no fibers can be seen in the grooves, and the surface of the walls is smooth with no irregularities. In Reference Example 1, where glass fibers are filled, glass fibers protrude from the walls of the grooves, bridging the gaps between opposing walls.

[0062] (Joining with other molded products) A polyamide elastomer (Vestamide® E40-S1, manufactured by Polypla Evonik Co., Ltd.) was prepared as the material for the other molded product. A resin molded product in which a groove 13 is formed on the laser irradiation surface 10s was inserted into an injection molding die with the laser irradiation surface 10s as the contact surface, and the polyamide elastomer, which is the material for the other molded product, was injection molded under the conditions of cylinder temperature 240°C, mold temperature 60°C, injection speed 30 mm / sec, holding pressure 35 MPa, and cooling time 30 sec to produce an integrated composite molded product. In this manner, composite molded products of Example 1 (member A), Comparative Example 1 (member B), and Reference Example 1 (member C) were manufactured by joining the resin molded product 10 of Example 1 (member A), Comparative Example 1 (member B), and Reference Example 1 (member C) with another molded product 20 made of polyamide elastomer.

[0063] (Evaluation of bonding strength) A 90° peel test was performed to evaluate the bonding strength between the resin molded product 10 of Example 1 (member A), Comparative Example 1 (member B), and Reference Example 1 (member C) and other tape-shaped molded product 20 made of polyamide elastomer.

[0064] The 90° peel test was performed using a SHIMADZU AUTOGRAPH AG-X plus as the test apparatus. The peel force (test force) required to peel off another molded product 20 in the shape of a tape (width 20 mm) from the resin molded product 10 by pulling it perpendicular to the laser irradiation surface 10s at a speed of 50 mm / min in the direction of 90°.

[0065] Table 1 below shows the maximum test force (maximum point test force: N) and the stress per unit length (maximum point stress / tape width: N / mm) measured by the 90° peel test.

[0066]

[0067] In Example 1, which corresponds to the resin molded product and composite molded product of the present invention, it can be seen that the bonding strength is significantly higher than in Comparative Example 1, which does not contain a filler. Furthermore, it can be seen that the bonding strength is comparable to that of Reference Example 1, in which glass fibers are included as a filler, and the glass fibers act as bridges between the grooves, resulting in a high anchoring effect between the molded product 20 and other molded products 20. Since carbon fibers are lighter than glass fibers, Example 1 has an advantage in terms of weight reduction compared to Reference Example 1.

[0068] 10: Resin molded product, 10': Pre-processed molded product (resin molded product), 10s: Laser irradiation surface (surface), 11: Resin, 12: Carbon fiber, 13: Groove, 13a: Wall, 13b: Bottom, 14: Recess, 20: Other molded product, 21: Protrusion, 24: Micro-protrusion, 30: Composite molded product

Claims

1. A resin molded product comprising carbon fiber and resin, wherein a groove is formed on the surface of the product, having a bottom portion and a pair of opposing wall portions, and the wall portions of the groove are not exposed and have an uneven surface.

2. The resin molded article according to claim 1, wherein the resin is a thermoplastic resin.

3. The resin molded article according to claim 1, wherein the resin is at least one selected from the group consisting of polyetheretherketone, polyphenylene sulfide, and liquid crystal polymer.

4. The resin molded article according to claim 1, wherein the groove is formed by irradiation with laser light.

5. A composite molded product in which another molded product is integrated into the surface of the resin molded product according to claim 1, on which the groove is formed.

6. The composite molded article according to claim 5, wherein a part of the other molded article is inserted into the groove.

7. A method for manufacturing a resin molded product comprising a groove forming step, in which a laser beam is irradiated onto at least a portion of the surface of a resin molded product containing carbon fibers and resin, thereby forming grooves having a bottom portion and a pair of opposing wall portions, wherein the wall portions do not expose the carbon fibers and have an uneven surface.

8. A method for manufacturing a composite molded product, comprising: a groove forming step of irradiating at least a portion of the surface of a resin molded product containing carbon fibers and resin with laser light to form grooves having a bottom portion and a pair of opposing wall portions, wherein the wall portions do not expose the carbon fibers and have an uneven surface; and a composite molding step of integrating the grooved surface with another material as a contact surface to manufacture a composite molded product.

9. The method for manufacturing a composite molded product according to claim 8, wherein the composite molding step is a step of manufacturing a composite injection molded product by integrating the surface on which the groove is formed with other materials by injection molding, with the groove being used as a contact surface.

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