Molding die and method for manufacturing resin product

Abstract

To reduce the manufacturing cost of a resin product formed by forming a coating film on the outer surface of a base. A molding die 10 has a first die 11 for molding the back surface 7 of a base 2, a second die 12 selectively moldable with the first die 11 for molding the front surface 6 of the base 2, and a third die 13 for forming a coating film 3 on the front surface 6. The first die 11 is provided with an insert 16 having an end surface 16a aligned with a die parting surface 15a and a molding surface 16b and is arranged to be recessed from the die parting surface 15a. In a state where the third die 13 is moldable with the first die 11, the insert 16 is located at a recessed position where the end surface 16a is recessed from the die parting surface 15a. Further, in this state, the molding surface 16b forms a first space 22a between the back surface 7 of the base 2. The first space 22a communicates with a second space 22b formed between the third die 13 and the front surface 6 of the base 2, and constitutes a part of a second cavity 22 for forming the coating film 3.

Description

Technical Field

[0001] This disclosure relates to a molding die and a method for manufacturing a resin product, specifically to a molding die for manufacturing a resin product having a coating film formed on the outer surface of a substrate that is a resin molded article, and a method for manufacturing a resin product having a coating film formed on the outer surface of a substrate using the molding die. Background Technology

[0002] A coating formation method known as in-mold coating has long been known. In-mold coating forms a coating film on the outer surface of a substrate by injecting paint into a mold in which a substrate has been placed. In in-mold coating, injection marks remain at the injection sites of the paint, and air accumulates at the endpoints, thus often forming excess shape portions at these locations.

[0004] If excess shapes are cut after coating is formed, it not only increases workload and cost but also reduces the quality of the cut surface. To solve this problem, an invention has been proposed that arranges injection marks and air accumulation portions on a non-designed surface of a resin product (Patent Document 1). In this invention, injection marks and air accumulation portions are arranged on a non-designed surface (i.e., back or rear) opposite to the designed surface (i.e., front or front side) of the resin product. A substrate of the resin product is formed using a substrate forming mold having a first substrate mold portion and a second substrate mold portion. A coating film of the resin product is formed using a coating forming mold having a first coating mold portion and a second coating mold portion prepared separately from the substrate forming mold.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2021-024239 Summary of the Invention The problem the invention aims to solve However, existing coating molding dies require separate first and second coating molds in addition to the first and second substrate molds of the substrate forming die. This increases not only the manufacturing cost of the forming die itself but also the need for production equipment containing both types of forming dies, leading to increased equipment costs. Furthermore, after forming the substrate (base, molded body, or molded article) using the substrate forming die, the substrate needs to be removed from the substrate forming die and placed into the coating molding die. Therefore, the manufacturing process is not only cumbersome but also time-consuming.

[0006] In view of the above background, one object of the present invention is to improve the manufacturing efficiency of resin products formed by forming a coating on the outer surface of a substrate as a resin molded article, and to reduce the manufacturing cost.

[0007] Technical means to solve the problem To solve the above problems, one embodiment of the present invention is a molding die (10) for manufacturing a resin product (1) formed by forming a coating film (3) on the outer surface of a substrate (2) as a resin molded article. The die includes: a first mold (11) for forming the back side (7) of the substrate; a second mold (12) selectively molded to the first mold for forming the front side (6) of the substrate; and a third mold (13) for forming the coating film (3) on the front side of the substrate. The first mold includes: a mold parting surface (15a) and a mold body (15) having a main forming surface (15b) for forming the main portion of the back side; an insert (16) having an end face (16a) aligned with the mold parting surface and a forming surface (16b) for forming a portion of the back side, and configured to be recessed from the mold parting surface; and a force-applying member (17) for applying force to the insert toward the mold parting surface. In the state where the second mold is molded with the first mold ( Figure 2 In this state, the insert is located at a reference position where the end face coincides with the mold parting surface. Furthermore, in this state, the forming surface defines the first cavity (20) for the substrate. In the state where the third mold and the first mold are closed (… Figure 3 In this state, the insert is located in a recessed position where the end face is recessed from the mold parting surface due to overcoming the force applied by the force-applying component. Furthermore, in this state, the forming surface forms a first space (22a) between itself and the back surface of the substrate. The first space communicates with the second space (22b) formed between the third mold and the front surface of the substrate, and constitutes part of the second cavity (22) for forming the coating film.

[0008] According to this embodiment, a substrate can be formed using a first mold and a second mold, and a coating film can be formed on the front side of the substrate in a continuous manner with the back side using the first mold and a third mold. Since it is not necessary to prepare a mold different from the first mold for forming a coating film on the back side of the substrate, the manufacturing cost of the forming mold can be reduced. Furthermore, since it is not necessary to demold the substrate from the first mold after forming it using the first mold and the second mold, the manufacturing operation of the resin product with the coating film is simplified. Therefore, the manufacturing operation of the resin product with the coating film can be performed efficiently, and the resin product can be manufactured inexpensively.

[0009] In the above embodiment, the third mold, when closed with the first mold, may have a protrusion (13c) that extends beyond the mold parting surface and protrudes to the side of the insert.

[0010] According to this embodiment, by closing the third mold with the first mold, the insert is pressed into the recessed position by the protrusion. Therefore, there is no need to perform the operation of placing or fixing the insert in the recessed position, and the coating formation operation becomes simple.

[0011] In the above embodiments, the shaped surface of the insert and the end face are continuous at an angle of 0 degrees or more and less than 90 degrees.

[0012] According to this embodiment, even if the insert is set to be vertically recessed into the mold parting surface, the first space communicating with the second space can be formed through the recess of the insert. Therefore, the shape of the mold body of the first mold and the insert becomes simple, and the increase in manufacturing costs can be suppressed.

[0013] Furthermore, in order to solve the above problems, another embodiment of the present invention is a method for manufacturing a resin product (1) formed by forming a coating film (3) on the outer surface of a substrate (2) using a molding die (10), which includes: a first step of closing a second mold (12) with a first mold (11) having an insert (16), and forming a first cavity (20) between the first mold and the second mold. Figure 4 (A)); the second step of injecting resin material into the first cavity to form the substrate (A) Figure 4 (B)); the third step of opening the first mold and the second mold, so that the second mold is separated from the first mold. Figure 4 (C)); the fourth step is to close the third mold (13) with the first mold in a manner that covers the substrate, and to form a second cavity (22) around the substrate for forming the coating film. Figure 5 (D)); and the fifth step of injecting the coating into the second cavity to form the coating film on the outer surface of the substrate. Figure 5 (E)). In the first and second steps described above, the insert is located at a reference position where the end face (16a) of the insert coincides with the mold parting surface (15a) of the first mold. In the second step, the forming surface (16b) of the insert forms a portion of the back surface (7) of the substrate. In the fourth and fifth steps described above, the insert is located at a recessed position where the end face of the insert is offset from the mold parting surface to the side of the first mold, and the forming surface of the insert forms a first space (22a) between itself and the back surface of the substrate. The first space communicates with the second space (22b) formed between the third mold and the front surface (6) of the substrate, constituting a portion of the second cavity. In the fifth step described above, the forming surface of the insert forms a portion of the coating film.

[0014] According to this embodiment, the first mold and the second mold used in the first step can be used to form a first space communicating with a second space formed on the front side of the substrate on the back side, and to form a coating film from the front side to the back side of the substrate. Therefore, it is not necessary to prepare a mold different from the first mold for forming a coating film on the back side of the substrate, thereby reducing the manufacturing cost of the forming mold. As a result, resin products with a coating film can be manufactured inexpensively.

[0015] In the above embodiment, in the third step, the second mold is detached from the first mold in a manner that maintains the state of the first mold holding the substrate, and in the fourth step, the third mold is closed with the first mold holding the substrate.

[0016] According to this embodiment, after the second step of forming the substrate using the first mold and the second mold, it is not necessary to remove the substrate from the first mold, making the manufacturing operation of forming a coated resin product easier. Therefore, the manufacturing operation of forming a coating on the outer surface of the substrate can be performed efficiently, and the manufacturing cost of the resin product can be reduced.

[0017] In the above embodiment, in the fourth step, the insert is pressed from the reference position to the recessed position by the protrusion (13c) formed on the third mold.

[0018] According to this embodiment, in the fourth step, apart from the operation of closing the third mold with the first mold, there is no need to separately move the insert to the recessed position and fix it. Therefore, the coating formation operation is simple.

[0019] The effects of the invention According to the above embodiments, it is possible to efficiently manufacture resin products by forming a coating film on the outer surface of a resin molded article substrate, and to reduce the manufacturing cost of resin products. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of the resin product involved in the implementation method.

[0021] Figure 2 This is a cross-sectional view of the substrate forming mold involved in the implementation method.

[0022] Figure 3 This is a cross-sectional view of the coating forming mold involved in the embodiment.

[0023] Figure 4 This is an explanatory diagram illustrating the manufacturing sequence of the resin product involved in the embodiment.

[0024] Figure 5This is an explanatory diagram illustrating the manufacturing sequence of the resin product involved in the embodiment. Detailed Implementation

[0025] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0026] Figure 1 This is a cross-sectional view of the resin product 1 involved in the embodiment. (As shown) Figure 1 As shown, resin product 1 has a substrate 2, which is a resin molded article, made of a first resin, and a coating 3, made of a second resin, formed on a portion of the outer surface of the substrate 2. The substrate 2 has a generally plate-shaped body 4 and a protrusion 5 protruding from the body 4.

[0027] The substrate 2 is an injection-molded article formed by injection molding of resin using the substrate molding die 10A described later. The protrusion 5 of the substrate 2 can be used, for example, as a mounting part for mounting the main body 4 of the substrate 2 to other parts, or as a support part for supporting other parts.

[0028] The matrix 2 can be a thermoplastic resin or a composite material in which glass, carbon fibers, talc particles, or other reinforcing materials are mixed into the thermoplastic resin. Examples of thermoplastic resins include acrylonitrile-butadiene-styrene (ABS), polycarbonate (PC), polymethyl methacrylate (PMMA), polycarbonate / acrylonitrile-butadiene-styrene (PC-ABS), polypropylene (PP), and polyethylene (PE). The matrix 2 can be transparent, translucent, or opaque, and can also be colorless or colored.

[0029] Coating 3 is an in-mold coating layer formed by using an in-mold coating method with a resin coating having a coating forming mold 10B described later. The resin coating can be a thermosetting resin coating or a thermoplastic resin coating. For example, a polyurethane resin coating can be used as the resin coating.

[0030] The coating 3 is formed on an entire surface of the substrate 2 (the surface facing the left side of the figure, i.e., the front surface 6). The front surface 6 of the substrate 2 with the coating 3 formed has a user-visible surface (hereinafter referred to as the design surface) in use, and the outer surface is covered by the coating 3 to improve appearance. In this embodiment, the entire front surface 6 of the substrate 2 does not constitute the design surface; rather, as shown in the figure, most of the area above the front surface 6 constitutes the design surface.

[0031] In base 2, all surfaces other than the designed surfaces are invisible to the user during use (hereinafter referred to as non-designed surfaces). The lower part of the front surface 6 of base 2 and the other surface opposite to the front surface 6 of base 2 (the surface facing the right side of the figure, i.e., the back surface 7) constitute the non-designed surfaces. Furthermore, the up-down and left-right directions are... Figure 1The reference is based on the condition of resin product 1, not on its usage state.

[0032] The coating 3 is formed not only on the designed surface area, but also continuously from the designed surface onto a portion of the non-designed surface. On the upper part of the substrate 2, since the designed surface extends to the upper end of the front side 6, the coating 3 is formed from the front side 6 to the back side 7 of the substrate 2. On the lower part of the substrate 2, since the designed surface does not extend to the lower end of the front side 6, the coating 3 is formed only on the front side 6 of the substrate 2 and not on the back side 7.

[0033] Next, the molding die 10 used to manufacture the resin product 1 having this structure will be described. The molding die 10 includes a substrate molding die 10A for manufacturing the substrate 2 of the resin product 1, and a coating molding die 10B for forming a coating film 3 on the outer surface of the substrate 2 by in-mold coating. Figure 2 This is a cross-sectional view of the substrate forming mold 10A involved in the embodiment. Figure 3 This is a cross-sectional view of the coating forming mold 10B according to the embodiment. Figure 2 As shown, the substrate forming mold 10A includes a first mold 11 and a second mold 12; as Figure 3 As shown, the coating forming mold 10B includes a first mold 11 and a third mold 13. These will be described in detail below.

[0034] like Figure 2 As shown, the substrate forming mold 10A includes a first mold 11 and a second mold 12 that is configured opposite to the first mold 11 and can be closed relative to the first mold 11.

[0035] The first mold 11 is a mold for forming the back surface 7 of the substrate 2. It includes a mold body 15 fixed to a fixing plate 14 and an insert 16 disposed in a notch formed on the mold body 15. The mold body 15 has a mold parting surface 15a and a main forming surface 15b recessed on the mold parting surface 15a and adapted in shape to the back surface 7 of the substrate 2. The notch is formed to span the outer periphery of the back surface 7 of the substrate 2 and the mold parting surface 15a. The insert 16 has a shape that fills the notch. The insert 16 has an end face 16a that forms part of the mold parting surface 15a and a forming surface 16b recessed on the end face 16a and adapted in shape to the outer periphery of the back surface 7 of the substrate 2. The forming surface 16b of the insert 16 is continuous with an inclination angle of less than 90 degrees relative to the end face 16a. The angle of the forming surface 16b relative to the end face 16a can be greater than 0 degrees and less than 90 degrees.

[0036] The notch is formed perpendicular to the mold parting surface 15a, and the insert 16 is disposed on the mold body 15 in a direction orthogonal to the mold parting surface 15a. On the side of the insert 16 opposite to the end face 16a, a spring member 17 (an example of a force-applying member) is provided as a force-applying means to apply force to the insert 16 toward the mold parting surface 15a, i.e., away from the fixed platen 14. In this embodiment, the spring member 17 is composed of a compression coil spring compressed between the fixed platen 14 and the insert 16. The spring member 17 may be composed of one or more compression coil springs. The spring member 17 may be a metal spring, a rubber spring, or an air spring, etc. The insert 16 is positioned at a reference position where the end face 16a coincides with the mold parting surface 15a of the mold body 15 by being forceped by the spring member 17. Figure 2 (as shown in the image). Alternatively, when the second mold 12 is not closed with the first mold 11, the insert 16 can also be positioned on the end face 16a further away from the fixed platen 14 than the mold parting surface 15a (in other words, a position protruding from the mold parting surface 15a).

[0037] The second mold 12 is a mold for forming the front surface 6 of the base 2. It is supported by a support device (not shown) and can be closed (also called mold closing) and opened relative to the first mold 11. The second mold 12 has a mold parting surface 12a that abuts against the mold parting surface 15a of the mold body 15 of the first mold 11, and a front forming surface 12b that is recessed on the mold parting surface 12a and whose shape is adapted to the front surface 6 of the base 2.

[0038] With the second mold 12 and the first mold 11 closed, a first cavity 20 for forming the substrate 2 is formed between the first mold 11 and the second mold 12. The first cavity 20 is defined by the main forming surface 15b of the mold body 15 of the first mold 11, the forming surface 16b of the insert 16, and the front forming surface 12b of the second mold 12. Uncured resin material made of the first resin is injected from a gate (not shown) and filled into the first cavity 20, and the substrate 2 is formed by cooling and hardening.

[0039] like Figure 3 As shown, the coating forming mold 10B includes a first mold 11 and a third mold 13 configured opposite to the first mold 11 and capable of being molded relative to the first mold 11. The first mold 11 is the same mold used in the substrate forming mold 10A. The third mold 13 is a mold for forming a coating 3 on the front surface 6 of the substrate 2, and it is supported by a support device (not shown) and can be molded relative to the first mold 11. The second mold 12 and the third mold 13 are selectively molded with the first mold 11 via the support device.

[0040] The support device may include, for example, a movable disk (not shown) on which the second mold 12 and the third mold 13 can be arranged side by side, and the movable disk is driven by a drive mechanism such as a rotating mechanism or a sliding mechanism, thereby being configured such that the second mold 12 and the third mold 13 can be selectively molded with the first mold 11. Alternatively, the molding machine may be configured to have the first mold 11 as an intermediate mold and rotate the movable disk and the intermediate mold, thereby using the second mold 12 and the third mold 13 to alternately mold with the first mold 11.

[0041] The third mold 13 includes a mold parting surface 13a, a coating forming surface 13b recessed on the mold parting surface 13a, and a protrusion 13c protruding from the mold parting surface 13a. The mold parting surface 13a of the third mold 13 is the surface that abuts against the mold parting surface 15a of the mold body 15 of the first mold 11 when the third mold 13 and the first mold 11 are closed. The coating forming surface 13b has a shape adapted to the portion of the coating 3 stacked on the front surface 6 of the substrate 2. The protrusion 13c is formed at a position opposite to the end face 16a of the insert 16. When the third mold 13 and the first mold 11 are closed, the protrusion 13c overcomes the force of the spring member 17 and moves the insert 16 toward the fixing plate 14. In this state, the insert 16 is positioned in a recessed position where the end face 16a is recessed from the mold parting surface 15a of the mold body 15. Figure 3 (as shown in the figure). The side of the protrusion 13c on the side of the coating forming surface 13b is located in a position continuous with the coating forming surface 13b and extends from the coating forming surface 13b.

[0042] With the third mold 13 and the first mold 11 closed, a cavity 21 adapted to the shape of the resin product 1 is formed between the first mold 11 and the third mold 13. With the substrate 2 housed in the cavity 21, a second cavity 22 adapted to the shape of the coating film 3 is formed around the substrate 2. The second cavity 22 is a cavity for shaping the coating film 3 formed on the outer surface of the substrate 2, and is defined by the outer surface of the substrate 2, the forming surface 16b of the insert 16, and the coating forming surface 13b of the third mold 13.

[0043] The second cavity 22 includes a first space 22a formed between the substrate 2 and the forming surface 16b of the insert 16, and a second space 22b formed between the substrate 2 and the coating forming surface 13b of the third mold 13. The first space 22a and the second space 22b are in communication with each other. Uncured resin coating made of the second resin is injected from a gate not shown and filled into the second cavity 22, and cured by cooling to form a coating film 3 in a manner that is stacked on the outer surface of the substrate 2.

[0044] As described above, the forming surface 16b of the insert 16 is inclined relative to the mold parting surface 15a. Therefore, even if the insert 16 is configured to be vertically recessed into the mold parting surface 15a, the recess of the insert 16 can form the first space 22a communicating with the second space 22b. Thus, the shapes of the mold body 15 of the first mold 11 and the insert 16 become simpler, and the increase in manufacturing costs can be suppressed.

[0045] Next, the method for manufacturing resin product 1 using the molding die 10 configured as described will be explained.

[0046] Figure 4 and Figure 5 This is an explanatory diagram illustrating the manufacturing sequence of resin product 1 according to the embodiment. First, as... Figure 4 As shown in (A), a first cavity 20 is formed between the first mold 11 and the second mold 12 by closing the second mold 12 with the first mold 11 (first step). In the first step, the insert 16 is positioned at a reference position where the end face 16a coincides with the mold parting surface 15a of the mold body 15 of the first mold 11.

[0047] Next, as Figure 4 As shown in (B), the substrate 2 is formed by injecting resin material from a gate (not shown) provided on the substrate forming mold 10A and injecting the resin material into the first cavity 20. In the second step, a portion of the back surface 7 of the substrate 2 is formed by the forming surface 16b of the insert 16.

[0048] After the resin material constituting matrix 2 has hardened, such as Figure 4 As shown in (C), the first mold 11 and the second mold 12 are opened, and the second mold 12 is detached from the first mold 11 (third step). At this time, the second mold 12 is detached from the first mold 11 while the first mold 11 is holding the substrate 2. Since it is not necessary to demold the substrate 2 from the first mold 11 after the second step of forming the substrate 2 using the substrate forming mold 10A, the manufacturing operation of the resin product 1 becomes easier.

[0049] After that, as Figure 5As shown in (D), by closing the third mold 13 with the first mold 11 to cover the substrate 2, a second cavity 22 for forming the coating film 3 is formed around the substrate 2 (fourth step). At this time, since the third mold 13 has a protrusion 13c, the insert 16 is pressed from the reference position to the recessed position by the protrusion 13c. That is, in the fourth step, the insert 16 is positioned in a recessed position where the end face 16a is offset from the mold parting surface 15a towards the first mold 11. Thus, since the third mold 13 has a protrusion 13c that extends beyond the mold parting surface 13a and protrudes to the side of the insert 16, there is no need to perform the operation of placing or fixing the insert 16 in the recessed position, and the coating film formation operation becomes simple.

[0050] Thus, the shaped surface 16b of the insert 16 (reference) Figure 2 , Figure 3 , Figure 5 (D) forms a first space 22a between itself and the back surface 7 of the substrate 2. See reference. Figure 3 As explained, the first space 22a communicates with the second space 22b formed between the third mold 13 and the front surface 6 of the substrate 2, and constitutes part of the second cavity 22. In the fourth process, since the insert 16 is pressed into the recessed position by the protrusion 13c of the third mold 13, there is no need to perform a separate operation of moving and fixing the insert 16 to the recessed position, except for the operation of closing the third mold 13 with the first mold 11. Therefore, the coating formation process is simple.

[0051] Next, as Figure 5 As shown in (E), resin coating is ejected from a gate (not shown) provided on the coating forming mold 10B and injected into the second cavity 22, thereby forming a coating 3 on the outer surface of the substrate 2 (step 5). When the resin coating is injected into the second cavity 22, it can be injected from the front side 6 of the substrate 2 to the back side 7, or it can be injected from the back side 7 of the substrate 2 to the front side 6. Alternatively, the resin coating can be split within the gate and injected separately into the portion on the front side 6 and the portion on the back side 7 of the second cavity 22.

[0052] After the resin coating constituting coating film 3 has hardened, as Figure 5 As shown in (F), the first mold 11 and the third mold 13 are opened, and the third mold 13 is detached from the first mold 11 (step 6). In addition, the resin product 1 is removed from the first mold 11. Thus, a resin product 1 is manufactured by forming a coating film 3 on the outer surface of the substrate 2 using the molding die 10.

[0053] Thus, in this embodiment, the substrate 2 can be formed using the first mold 11 and the second mold 12, and the coating film 3 can be formed on the front side 6 of the substrate 2, which is continuous with the back side 7, by in-mold coating using the first mold 11 and the third mold 13. That is, by using the first mold 11 and the third mold 13 used in the first step, and by recessing the insert 16 of the first mold 11 in the fourth step, a first space 22a communicating with the second space 22b formed on the back side 7 side of the substrate 2 can be formed. Then, since the second cavity 22 includes the first space 22a and the second space 22b, the coating film 3 can be formed in a manner that extends from the front side 6 side of the substrate 2 to the back side 7 side. Therefore, the coating film 3 can be formed on the back side 7 of the substrate 2 while the formed substrate 2 is held in the first mold 11, thereby facilitating the manufacturing operation of the resin product 1. Furthermore, since there is no need to prepare a different mold than the first mold 11 for forming the coating 3 on the back side 7 of the substrate 2, the manufacturing cost of the molding mold 10 is reduced. As a result, the manufacturing operation of the resin product 1 with the coating 3 can be performed efficiently, and the resin product 1 can be manufactured inexpensively.

[0054] The description of the specific embodiments concludes here. However, the present invention is not limited to the above embodiments and can be implemented in a wide range of variations. For example, the structure of the insert 16 is not limited to a structure that is vertically recessed into the mold parting surface 15a. As long as the insert 16 has a structure that forms a first space 22a communicating with the second space 22b through the recess, it is acceptable. For example, the insert 16 may also be in a form that is obliquely pressed in and recessed. Furthermore, in the above embodiments, one insert 16 is provided on the first mold 11, but two or more inserts 16 may also be provided on the first mold 11. In this case, the multiple inserts 16 may be arranged separately from each other or arranged adjacently in a continuous manner. In addition, the specific structure, arrangement, quantity, material, manufacturing steps, etc. of each component part can be appropriately changed within the scope of the present invention. On the other hand, not all of the constituent elements shown in the above embodiments are necessary and can be appropriately selected.

[0055] Symbol Explanation 1: Resin products 2: Matrix 3: Coating 4: Main Body 5: convex part 6: Front 7: Back 10: Forming mold 10A: Matrix forming mold 10B: Coating forming mold 11: Mold No. 1 12: Mold No. 2 12a: Mold parting surface 12b: Front forming surface 13: Mold No. 3 13a: Mold parting surface 13b: Coating forming surface 13c: Protrusion 14: Fixed plate 15: Main body of the mold 15a: Mold parting surface 15b: Main forming surface 16: Inserts 16a: End face 16b: Forming surface 17: Spring components (force-applying components) 20: 1st cavity 21: Cavity 22: 2nd cavity 22a: First Space 22b: Second Space

Claims

1. A molding die for manufacturing a resin product formed by forming a coating film on the outer surface of a substrate serving as a resin molded article, comprising: A first mold for forming the back side of the substrate; A second mold, which can be selectively molded together with the first mold, for forming the front side of the substrate, and a third mold for forming the coating film on the front side of the substrate; The first mold comprises: A mold body having a mold parting surface and a main forming surface for forming the main part of the back side; An insert having an end face aligned with the mold parting surface and a forming surface for forming a portion of the back side, and configured to be recessed from the mold parting surface, and A force-applying component that applies force to the insert toward the mold parting surface. With the second mold and the first mold closed, the insert is located at a reference position where its end face coincides with the mold parting surface, and the forming surface defines the first cavity for the substrate. When the third mold and the first mold are closed, the insert is located in a recessed position where the end face is recessed from the mold parting surface due to the force applied by the force-applying component, and the forming surface forms a first space between itself and the back surface of the substrate. The first space communicates with a second space formed between the third mold and the front surface of the substrate and constitutes part of a second cavity for forming the coating film.

2. The forming mold according to claim 1, wherein, When the third mold is closed with the first mold, it has a protrusion that extends beyond the mold parting surface and protrudes to the insert side.

3. The forming mold according to claim 1 or 2, wherein, The shaped surface of the insert is continuous with the end face at an angle greater than 0 degrees and less than 90 degrees.

4. A method for manufacturing a resin product, comprising forming a coating film on the outer surface of a substrate using a molding die, comprising: The first step involves closing the second mold with the first mold containing the insert to form a first cavity between the first mold and the second mold; The second step involves injecting resin material into the first cavity to form the substrate. The third step involves opening the first mold and the second mold, allowing the second mold to detach from the first mold; A fourth step involves closing the third mold with the first mold in a manner that covers the substrate, forming a second cavity around the substrate for forming the coating film; and The fifth step involves injecting the coating into the second cavity to form the coating film on the outer surface of the substrate. In the first and second processes, the insert is located at a reference position where its end face coincides with the mold parting surface of the first mold. In the second step, the forming surface of the insert forms a portion of the back side of the substrate. In the fourth and fifth steps, the insert is located in a recessed position where its end face is offset from the mold parting surface to the first mold side, and the forming surface of the insert forms a first space between itself and the back surface of the substrate. This first space communicates with a second space formed between the front surface of the third mold and the substrate, constituting part of the second cavity. In the fifth step, the forming surface of the insert forms a portion of the coating.

5. The manufacturing method according to claim 4, wherein, In the third step, to maintain the state in which the first mold holds the substrate, the second mold is detached from the first mold. In the fourth step, the third mold is closed with the first mold that holds the substrate.

6. The manufacturing method according to claim 4 or 5, wherein, In the fourth step, the insert is pressed from the reference position into the recessed position by the protrusion formed on the third mold.

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