Mold and method for producing resin product

Abstract

The present invention reduces the production cost of a resin product obtained by forming a coating film on the outer surface of a base.　A mold 10 comprises: a first mold 11 for forming a back surface 7 of a base 2; a second mold 12, which is configured so as to be selectively clampable to the first mold 11 and which is for forming a front surface 6 of the base 2; and a third mold 13 for forming a coating film 3 on the front surface 6 of the base 2. The first mold 11 is equipped with an insert 16 which has a molding surface 16b and an end surface 16a conforming to a mold parting surface 15a and which is provided so as to be retractable from the mold parting surface 15a. In a state where the third mold 13 has been clamped to the first mold 11, the insert 16 is in a retracted position where the end surface 16a has retracted from the mold parting surface 15a. In this state, the molding surface 16b forms a first space 22a between itself and the back surface 7 of the base 2. The first space 22a communicates with a second space 22b formed between the third mold 13 and the front surface 6 of the base 2 and serves as some of a second cavity 22 for forming the coating film 3.

Description

Molding mold and resin product manufacturing method

[0001] The present disclosure relates to a molding die and a method for manufacturing a resin product, and more particularly to a molding die for manufacturing a resin product formed by forming a coating film on the outer surface of a base that is a resin molded product, and a method for manufacturing a resin product formed by forming a coating film on the outer surface of a base using a molding die.

[0002] A conventional coating method known as in-mold coating is to form a coating on the outer surface of a substrate by injecting paint into a mold in which the substrate is set. In-mold coating leaves injection marks where the paint is injected and creates air pockets at the end point, resulting in the formation of excess shaped portions at these locations.

[0003] Cutting off the excess shape after forming a coating film increases the effort and cost, and also reduces the quality of the cut surface. To solve this problem, an invention has been proposed in which injection marks and air reservoirs are located on the non-design surface of a resin product (Patent Document 1). In this invention, the injection marks and air reservoirs are located on the non-design surface (i.e., the back surface or rear face) opposite the design surface (i.e., the front surface or front face) of the resin product. The substrate of the resin product is molded using a substrate molding die comprising a first substrate molding part and a second substrate molding part. The coating film of the resin product is molded using a coating molding die comprising a first coating molding part and a second coating molding part prepared separately from the substrate molding die.

[0004] Japanese Patent Application Laid-Open No. 2021-024239

[0005] However, conventional coating molds require the preparation of a first coating mold portion and a second coating mold portion in addition to the first substrate mold portion and the second substrate mold portion of the substrate mold. This increases the manufacturing cost of the mold and requires production equipment including two molds, which increases the equipment cost. Furthermore, after molding the substrate (substrate, molded body, or molded product) using the substrate mold, the substrate must be removed from the substrate mold and set in the coating mold. This makes the manufacturing process complicated and increases the time required for manufacturing.

[0006] In view of the above background, an object of the present invention is to improve the efficiency of the manufacturing process of a resin product in which a coating film is formed on the outer surface of a substrate that is a resin molded product, and to reduce the manufacturing cost.

[0007] In order to solve the above-mentioned problems, one aspect of the present invention is a molding die (10) for manufacturing a resin product (1) having a coating film (3) formed on the outer surface of a base (2) that is a resin molded product, the molding die (10) comprising: a first mold (11) for molding the back surface (7) of the base; a second mold (12) for molding the front surface (6) of the base, configured to be selectively clamped to the first mold; and a third mold (13) for forming the coating film (3) on the front surface of the base. The first mold comprises a mold body (15) having a mold parting surface (15a) and a main molding surface (15b) for molding a main portion of the back surface; a core (16) having an end surface (16a) matching the mold parting surface and a molding surface (16b) for molding a portion of the back surface and provided so as to be recessed from the mold parting surface; and a biasing member (17) for biasing the core toward the mold parting surface. When the second mold is clamped to the first mold (FIG. 2), the insert is in a reference position where the end face coincides with the mold parting surface. In this state, the molding surface defines a first cavity (20) for the substrate. When the third mold is clamped to the first mold (FIG. 3), the insert is in a recessed position where the end face is recessed from the mold parting surface against the biasing force of the biasing member. In this state, the molding surface forms a first space (22a) between the rear surface of the substrate and the insert. The first space is continuous with a second space (22b) formed between the third mold and the front surface of the substrate, and forms part of the second cavity (22) for forming the coating film.

[0008] According to this aspect, the base is molded using the first mold and the second mold, and the first mold and the third mold are used to form a coating film on the front surface of the base by in-mold coating so that the coating film is continuous with the back surface. Since there is no need to prepare a mold separate from the first mold to form a coating film on the back surface of the base, the manufacturing cost of the molding mold can be reduced. Furthermore, since there is no need to remove the base from the first mold after molding it using the first mold and the second mold, the manufacturing process of a resin product on which a coating film has been formed is easy. These features allow the manufacturing process of a resin product on which a coating film has been formed to be carried out efficiently, and resin products can be manufactured inexpensively.

[0009] In the above aspect, the third mold may have a protruding portion (13c) that protrudes beyond the mold parting surface toward the insert when the third mold is clamped to the first mold.

[0010] According to this aspect, the insert is pushed into the recessed position by the protruding portion by clamping the third mold to the first mold, thereby eliminating the need for the work of placing or fixing the insert in the recessed position, and simplifying the coating film formation work.

[0011] In the above aspect, the molding surface of the insert may be continuous with the end surface at an angle of 0 degrees or more and less than 90 degrees.

[0012] According to this aspect, even if the insert is provided so as to be recessed perpendicular to the mold parting surface, the recessed insert forms the first space that is continuous with the second space. This simplifies the shapes of the mold body and insert of the first mold, and suppresses increases in their manufacturing costs.

[0013] Another aspect of the present invention, which aims to solve the above-mentioned problems, is a method for manufacturing a resin product (1) by forming a coating film (3) on the outer surface of a substrate (2) using a molding die (10), the method comprising a first step (FIG. 4(A)) of clamping a second mold (12) to a first mold (11) equipped with a core (16) to form a first cavity (20) between the first mold and the second mold, and a second step (FIG. The method includes a first step (FIG. 4(B)) of opening the first mold and the second mold and removing the second mold from the first mold (FIG. 4(C)), a fourth step (FIG. 5(D)) of clamping a third mold (13) to the first mold so as to cover the base, thereby forming a second cavity (22) for forming the coating film around the base, and a fifth step (FIG. 5(E)) of injecting paint into the second cavity and forming the coating film on the outer surface of the base. In the first and second steps, the insert is located at a reference position where the end face (16a) of the insert coincides with the mold parting face (15a) of the first mold. In the second step, the molding surface (16b) of the insert molds a part of the back surface (7) of the base. In the fourth and fifth steps, the insert is located in a recessed position where the end face of the insert is offset from the mold parting surface toward the first mold, and the molding surface of the insert forms a first space (22a) between the rear surface of the base. The first space is continuous with a second space (22b) formed between the third mold and the front surface (6) of the base, and forms part of the second cavity (22). In the fifth step, the molding surface of the insert molds part of the coating film.

[0014] According to this aspect, the first and third molds used in the first step are used to form a first space on the back side of the base, which is continuous with the second space formed on the front side of the base, and the coating film can be molded so as to extend from the front side to the back side of the base. Therefore, there is no need to prepare a mold separate from the first mold to form a coating film on the back side of the base, which reduces the manufacturing cost of the molding die. This allows resin products with coating films to be manufactured inexpensively.

[0015] In the above aspect, in the third step, the second mold is detached from the first mold so that the first mold maintains the state in which it holds the base, and in the fourth step, the third mold is clamped to the first mold holding the base.

[0016] According to this aspect, since there is no need to remove the base from the first mold after the second step in which the base is molded using the first mold and the second mold, the manufacturing process for the resin product on which the coating film is formed is easy. This allows the manufacturing process for forming the coating film on the outer surface of the base to be carried out efficiently, and also reduces the manufacturing cost of the resin product.

[0017] In the above aspect, in the fourth step, the insert may be pushed from the reference position into the recessed position by a protrusion (13c) formed on the third mold.

[0018] According to this aspect, there is no need to perform the operation of moving the insert to the recessed position and fixing it there in addition to the operation of clamping the third mold to the first mold in the fourth step, which simplifies the coating film formation operation.

[0019] According to the above-described embodiment, the manufacturing process of a resin product in which a coating film is formed on the outer surface of a base body that is a resin molded product can be carried out efficiently, and the manufacturing cost of the resin product can be reduced.

[0020] Cross-sectional view of a resin product according to an embodiment Cross-sectional view of a substrate molding die according to an embodiment Cross-sectional view of a coating molding die according to an embodiment Descriptive view of a manufacturing procedure for a resin product according to an embodiment Descriptive view of a manufacturing procedure for a resin product according to an embodiment

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0022] Fig. 1 is a cross-sectional view of a resin article 1 according to an embodiment. As shown in Fig. 1, the resin article 1 has a base 2, which is a resin molded article made of a first resin, and a coating film 3 made of a second resin formed on a part of the outer surface of the base 2. The base 2 has a generally plate-shaped main body 4 and a protrusion 5 protruding from the main body 4.

[0023] The base 2 is an injection-molded product formed by injection molding of a resin using a base molding die 10A described below. The protrusion 5 of the base 2 may be used, for example, as an attachment portion for attaching the main body 4 of the base 2 to another component, or as a support portion for supporting another member.

[0024] The substrate 2 may be made of a thermoplastic resin or a composite material obtained by compounding a thermoplastic resin with a reinforcing material such as glass or carbon fibers or talc particles. Examples of thermoplastic resins that may be used include acrylonitrile butadiene styrene resin (ABS), polycarbonate resin (PC), polymethyl methacrylate resin (PMMA), polycarbonate / acrylonitrile butadiene styrene resin (PC-ABS), polypropylene (PP), and polyethylene (PE). The substrate 2 may be transparent, translucent, or opaque, and may be colorless or colored.

[0025] The coating film 3 is an in-mold coating formed by an in-mold coating method using a coating film forming mold 10B described below. The resin coating may be a thermosetting resin coating or a thermoplastic resin coating. For example, a polyurethane resin coating may be used as the resin coating.

[0026] The coating film 3 is formed over the entirety of one surface (the surface facing the left side in the figure, the front surface 6) of the base 2. The front surface 6 of the base 2 on which the coating film 3 is formed has a surface (hereinafter referred to as the design surface) that is visible to the user in use, and the outer surface is covered with the coating film 3 to improve appearance. In this embodiment, the entire front surface 6 of the base 2 does not constitute the design surface, but rather most of the upper part of the front surface 6 constitutes the design surface, as shown in the range in the figure.

[0027] Surfaces of the base 2 other than the design surface are surfaces that are not visible to the user when in use (hereinafter referred to as non-design surfaces). The lower part of the front surface 6 of the base 2 and the entire other surface of the base 2 opposite the front surface 6 (the surface facing right in the figure, i.e., the back surface 7) form the non-design surface. Note that the up / down and left / right directions are based on Figure 1 and not on the state in which the resin product 1 is in use.

[0028] The coating film 3 is not formed only on the design surface area, but is also formed continuously from the design surface on a portion of the non-design surface. In the upper part of the base 2, the design surface extends to the upper end of the front surface 6, so the coating film 3 is formed from the front surface 6 to the back surface 7 of the base 2. In the lower part of the base 2, the design surface does not extend to the lower end of the front surface 6, so the coating film 3 is formed only on the front surface 6 of the base 2, and not on the back surface 7.

[0029] Next, a molding die 10 for producing a resin product 1 having such a configuration will be described. The molding die 10 includes a base molding die 10A for producing the base 2 of the resin product 1, and a coating film molding die 10B for forming a coating film 3 on the outer surface of the base 2 by in-mold coating. Fig. 2 is a cross-sectional view of the base molding die 10A according to the embodiment, and Fig. 3 is a cross-sectional view of the coating film molding die 10B according to the embodiment. The base molding die 10A is configured to include a first mold 11 and a second mold 12 as shown in Fig. 2, and the coating film molding die 10B is configured to include a first mold 11 and a third mold 13 as shown in Fig. 3. These will be described in detail below.

[0030] As shown in FIG. 2, the base molding die 10A includes a first die 11 and a second die 12 that is disposed opposite the first die 11 and that is configured to be clamped to the first die 11.

[0031] The first mold 11 is a mold for molding the back surface 7 of the base 2 and includes a mold body 15 fixed to a fixed platen 14 and a core insert 16 provided in a missing portion formed in the mold body 15. The mold body 15 includes a mold parting surface 15a and a main molding surface 15b recessed in the mold parting surface 15a and shaped to fit the back surface 7 of the base 2. The missing portion is formed to extend from the outer periphery of the back surface 7 of the base 2 to the mold parting surface 15a. The core insert 16 has a shape that complements this missing portion. The core insert 16 includes an end surface 16a that forms a part of the mold parting surface 15a and a molding surface 16b recessed in the end surface 16a and shaped to fit the outer periphery of the back surface 7 of the base 2. The molding surface 16b of the core insert 16 is continuous with the end surface 16a at an inclination angle of less than 90 degrees. The angle of the molding surface 16b with respect to the end surface 16a may be greater than or equal to 0 degrees and less than 90 degrees.

[0032] The recess is formed perpendicular to the mold parting surface 15a, and the insert 16 is provided on the mold body 15 so as to be movable in a direction perpendicular to the mold parting surface 15a. A spring member 17 (an example of a biasing member) is provided on the side opposite the end face 16a of the insert 16 as biasing means for biasing the insert 16 toward the mold parting surface 15a, i.e., in a direction away from the fixed platen 14. In this embodiment, the spring member 17 is formed by a compression coil spring compressed between the fixed platen 14 and the insert 16. The spring member 17 may be formed by one or more compression coil springs. The spring member 17 may be a metal spring, a rubber spring, an air spring, or the like. The insert 16 is biased by the spring member 17 to be positioned at a reference position (the position shown in FIG. 2 ) where the end face 16a coincides with the mold parting surface 15a of the mold body 15. Alternatively, when the second mold 12 is not closed to the first mold 11, the insert 16 may be positioned such that the end face 16a is farther from the fixed platen 14 than the mold parting surface 15a (in other words, at a position protruding from the mold parting surface 15a).

[0033] The second mold 12 is a mold for molding the front surface 6 of the base 2, and is supported by a support device (not shown) so as to be capable of clamping (also referred to as mold closing) and opening relative to the first mold 11. The second mold 12 is equipped with 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 surface molding surface 12b that is recessed in the mold parting surface 12a and has a shape that fits the front surface 6 of the base 2.

[0034] When the second mold 12 is clamped to the first mold 11, a first cavity 20 for molding the base body 2 is formed between the first mold 11 and the second mold 12. The first cavity 20 is defined by the main molding surface 15b of the mold body 15 of the first mold 11, the molding surface 16b of the insert 16, and the front molding surface 12b of the second mold 12. An uncured resin material made of a first resin is injected from a gate (not shown) to fill the first cavity 20, and is cooled and cured to mold the base body 2.

[0035] As shown in Figure 3, the coating film molding mold 10B includes a first mold 11 and a third mold 13 that is disposed opposite the first mold 11 and is configured to be clampable to the first mold 11. The first mold 11 is the same as that used in the base molding mold 10A. The third mold 13 is a mold for molding the coating film 3 on the front surface 6 of the base 2, and is supported by a support device (not shown) so that it can be clamped and opened relative to the first mold 11. The second mold 12 and the third mold 13 are selectively clamped to the first mold 11 by the support device.

[0036] The support device may be configured to include, for example, a movable platen (not shown) on which the second mold 12 and the third mold 13 can be mounted side by side, and to selectively clamp the second mold 12 and the third mold 13 to the first mold 11 by driving the movable platen with a driving mechanism such as a rotation mechanism or a slide mechanism. Alternatively, the molding machine may be configured to include the first mold 11 as an intermediate mold, and to switch the mold clamped to the first mold 11 between the second mold 12 and the third mold 13 by rotating the movable platen or the intermediate mold.

[0037] The third mold 13 has a mold parting surface 13a, a coating film molding surface 13b recessed in 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 is clamped to the first mold 11. The coating film molding surface 13b has a shape that fits the portion of the coating film 3 that will be laminated on the front surface 6 of the substrate 2. The protrusion 13c is formed in a position opposite an end surface 16a of the insert 16. When the third mold 13 is clamped to the first mold 11, the protrusion 13c moves the insert 16 toward the fixed platen 14 against the biasing force of the spring member 17. In this state, the insert 16 is positioned at a recessed position (the position shown in FIG. 3) where the end face 16a is recessed from the mold parting surface 15a of the mold body 15. The side face of the protruding portion 13c on the coating film molding surface 13b side is in a position continuous with the coating film molding surface 13b, extending the coating film molding surface 13b.

[0038] When the third mold 13 is clamped to the first mold 11, a cavity 21 having a shape that fits the resin product 1 is formed between the first mold 11 and the third mold 13. When the base 2 is housed in the cavity 21, a second cavity 22 having a shape that fits the coating film 3 is formed around the base 2. The second cavity 22 is for molding the coating film 3 that is formed on the outer surface of the base 2, and is defined by the outer surface of the base 2, the molding surface 16b of the insert 16, and the coating film molding surface 13b of the third mold 13.

[0039] The second cavity 22 includes a first space 22a formed between the base 2 and the molding surface 16b of the insert 16, and a second space 22b formed between the base 2 and the coating film molding surface 13b of the third mold 13. The first space 22a and the second space 22b are continuous with each other. Uncured resin paint made of the second resin is injected from a gate (not shown) to fill the second cavity 22, and is cooled and cured to form the coating film 3 so as to be laminated on the outer surface of the base 2.

[0040] As described above, the molding surface 16b of the insert 16 is inclined relative to the mold parting surface 15a. As a result, even if the insert 16 is provided so as to be recessed perpendicular to the mold parting surface 15a, the recess of the insert 16 forms the first space 22a that is continuous with the second space 22b. This simplifies the shapes of the mold body 15 and insert 16 of the first mold 11, and suppresses increases in their manufacturing costs.

[0041] Next, a method for manufacturing the resin article 1 using the molding die 10 configured in this manner will be described.

[0042] 4 and 5 are explanatory diagrams of the manufacturing procedure for the resin product 1 according to the embodiment. First, as shown in Fig. 4(A), the second mold 12 is clamped to the first mold 11 to form a first cavity 20 between the first mold 11 and the second mold 12 (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.

[0043] 4(B), a resin material is injected from a gate (not shown) provided in the base molding die 10A into the first cavity 20, thereby forming the base 2 (second step). In the second step, a part of the back surface 7 of the base 2 is formed by the molding surface 16b of the insert 16.

[0044] After the resin material forming the base 2 has hardened, the first mold 11 and the second mold 12 are opened, and the second mold 12 is removed from the first mold 11 (third step), as shown in Figure 4(C). At this time, the second mold 12 is removed from the first mold 11 so that the first mold 11 maintains the state in which it holds the base 2. Since there is no need to remove the base 2 from the first mold 11 after the second step in which the base 2 is molded using the base molding mold 10A, the manufacturing process of the resin product 1 is facilitated.

[0045] 5(D), a third mold 13 is clamped to the first mold 11 so as to cover the base 2, thereby forming a second cavity 22 for forming the coating film 3 around the base 2 (fourth step). At this time, because the third mold 13 has a protruding portion 13c, the protruding portion 13c pushes the insert 16 from its reference position to the recessed position. That is, in the fourth step, the insert 16 is positioned at a recessed position where its end face 16a is offset from the mold parting surface 15a toward the first mold 11. In this way, because the third mold 13 has a protruding portion 13c that protrudes toward the insert 16 beyond the mold parting surface 13a, the work of positioning or fixing the insert 16 at the recessed position is unnecessary, simplifying the coating film formation work.

[0046] As a result, a first space 22a is formed between the molding surface 16b of the core 16 (see Figures 2, 3, and 5(D)) and the back surface 7 of the base 2. As explained with reference to Figure 3, the first space 22a is continuous with the second space 22b formed between the third mold 13 and the front surface 6 of the base 2, and forms part of the second cavity 22. In the fourth step, the core 16 is pressed into the recessed position by the protruding portion 13c of the third mold 13, so there is no need to perform an operation of moving the core 16 to the recessed position and fixing it there in addition to the operation of clamping the third mold 13 to the first mold 11. This simplifies the coating film formation operation.

[0047] 5(E), a resin coating material is injected into the second cavity 22 through a gate (not shown) provided in the coating mold 10B, thereby forming a coating film 3 on the outer surface of the substrate 2 (step 5). When the resin coating material is injected into the second cavity 22, it may be injected so as to wrap around from the front surface 6 side to the back surface 7 side of the substrate 2, or from the back surface 7 side to the front surface 6 side. Alternatively, the resin coating material may be branched within the gate and injected into both the portion of the second cavity 22 on the front surface 6 side and the portion on the back surface 7 side.

[0048] After the resin coating forming the coating film 3 has hardened, the first mold 11 and the third mold 13 are opened, and the third mold 13 is removed from the first mold 11 (sixth step), as shown in Figure 5(F). The resin article 1 is then removed from the first mold 11. This completes the production of the resin article 1 having the coating film 3 formed on the outer surface of the substrate 2 using the molding die 10.

[0049] As described above, in this embodiment, the base 2 is molded using the first mold 11 and the second mold 12, and the first mold 11 and the third mold 13 are used to form the coating film 3 by in-mold coating on the front surface 6 of the base 2 so as to be continuous with the back surface 7. That is, using the first mold 11 used in the first step and the third mold 13, the insert 16 of the first mold 11 is recessed in the fourth step to form the first space 22a on the back surface 7 of the base 2, which is continuous with the second space 22b formed on the front surface 6 of the base 2. Since the second cavity 22 includes the first space 22a and the second space 22b, the coating film 3 can be molded so as to extend from the front surface 6 to the back surface 7 of the base 2. Therefore, the coating film 3 can be formed on the back surface 7 of the base 2 while the molded base 2 is held in the first mold 11, facilitating the manufacturing process of the resin product 1. Furthermore, since there is no need to prepare a mold separate from the first mold 11 for forming the coating film 3 on the rear surface 7 of the substrate 2, the manufacturing cost of the molding die 10 is reduced. This allows the manufacturing process of the resin article 1 on which the coating film 3 is formed to be carried out efficiently, and also makes it possible to manufacture the resin article 1 inexpensively.

[0050] Although the description of the specific embodiment has been completed, the present invention is not limited to the above embodiment and can be widely modified. For example, the structure of the core 16 is not limited to a recess perpendicular to the mold parting surface 15a. The core 16 may have a structure that forms a first space 22a connected to the second space 22b by being recessed. For example, the core 16 may be recessed by being pressed obliquely against the mold parting surface 15a. In the above embodiment, one core 16 is provided in the first mold 11. However, two or more cores 16 may be provided in the first mold 11. In this case, the multiple cores 16 may be arranged spaced apart from each other or adjacently arranged so as to be continuous. Furthermore, the specific configuration, arrangement, quantity, materials, manufacturing procedure, etc. of each component and part may be modified as appropriate without departing from the spirit of the present invention. Meanwhile, not all of the components shown in the above embodiment are necessarily required and may be selected as appropriate.

[0051] REFERENCE SIGNS LIST 1: Resin product 2: Base body 3: Coating film 4: Main body 5: Convex portion 6: Front surface 7: Back surface 10: Mold 10A: Base body molding mold 10B: Coating film molding mold 11: First mold 12: Second mold 12a: Mold parting surface 12b: Front surface molding surface 13: Third mold 13a: Mold parting surface 13b: Coating film molding surface 13c: Protrusion 14: Fixed platen 15: Mold body 15a: Mold parting surface 15b: Main molding surface 16: Insert 16a: End surface 16b: Molding surface 17: Spring member (biasing member) 20: First cavity 21: Cavity 22: Second cavity 22a: First space 22b: Second space

Claims

1. A molding die for manufacturing a resin product in which a coating film is formed on the outer surface of a base, which is a resin molded product, comprising: a first mold for molding the back surface of the base; a second mold for molding the front surface of the base, both configured to be selectively clamped to the first mold; and a third mold for forming the coating film on the front surface of the base; the first mold comprises a mold body having a mold parting surface and a main molding surface for molding a main portion of the back surface; a nest having an end surface that matches the mold parting surface and a molding surface for molding a portion of the back surface and provided so as to be recessed from the mold parting surface; and a biasing member that biases the nest toward the mold parting surface; when the second mold is clamped to the first mold, the end surface of the nest is in a reference position that coincides with the mold parting surface, and the molding surface defines a first cavity for the base; When the third mold is clamped to the first mold, the end face of the insert is in a recessed position recessed from the mold parting surface against the biasing force of the biasing member, and the molding surface forms a first space between itself and the back surface of the base, and the first space is continuous with a second space formed between the third mold and the front surface of the base and forms part of a second cavity for forming the coating film.

2. A molding die according to claim 1, wherein the third die has a protruding portion that protrudes beyond the die parting surface toward the insert when clamped to the first die.

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

4. A method for manufacturing a resin product by forming a coating film on the outer surface of a base using a molding die, comprising: a first step of clamping a second mold onto a first mold having a molding insert to form a first cavity between the first mold and the second mold; a second step of injecting a resin material into the first cavity to mold the base; a third step of opening the first mold and the second mold and removing the second mold from the first mold; a fourth step of clamping a third mold onto the first mold so as to cover the base to form a second cavity for forming the coating film around the base; and a fifth step of injecting paint into the second cavity to form the coating film on the outer surface of the base, wherein in the first and second steps, the molding insert is located at a reference position where an end face of the molding insert coincides with the mold parting surface of the first mold; and in the second step, the molding surface of the molding insert molds part of the back surface of the base, a method for manufacturing a resin product, wherein in the fourth and fifth steps, the insert is located in a recessed position where the end face of the insert is offset from the mold parting surface toward the first mold, and the molding surface of the insert forms a first space between itself and the back surface of the base, and the first space is continuous with a second space formed between the third mold and the front surface of the base and forms part of the second cavity; and in the fifth step, the molding surface of the insert molds part of the coating film.

5. A method for manufacturing a resin product as described in claim 4, wherein in the third step, the second mold is detached from the first mold so that the first mold maintains the state in which it holds the base, and in the fourth step, the third mold is clamped to the first mold holding the base.

6. A method for manufacturing a resin product as described in claim 4 or 5, wherein in the fourth step, the insert is pushed from the reference position into the recessed position by a protrusion formed on the third mold.

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