Mold set for in-mold coating and method for manufacturing in-mold coated component

Abstract

Provided is a mold set for in-mold coating which does not require a cutting step as a separate step for removing a paint injection gate and an excess coating part. This mold set for in-mold coating comprises: resin molded article molds including a first core mold for forming a resin molded article and a resin molded article cavity mold; and coating film molds including a second core mold for forming a coating film on a surface of the resin molded article and a coating film cavity mold. When the first core mold and the resin molded article cavity mold are clamped, the resin molded article molds define: a resin molded article cavity; and a cavity for a gate part which, at the time of forming the coating film, serves as a base of a paint flow path from a paint injection port to the resin molding cavity, or a cavity for an auxiliary part which, at the time of forming the coating film, serves as a base of an excess coating part for flowing excess paint from an end part of the resin molded article cavity. When the resin molded article is placed on the second core mold and the second core mold and the coating film cavity mold are clamped, the coating film molds define a cavity for the paint flow path through which paint flows from the paint injection port to the resin molded article, or a cavity for the excess coating part for flowing the excess paint from an end part of the resin molded article. The gap between the second core mold and the coating film cavity mold is narrower at the boundary between the paint flow path and the resin molded article than on both the resin molded article side and on the coating flow path side, and / or the gap between the second core mold and the coating film cavity mold is narrower at the boundary between the resin molded article and the excess coating part than on both the resin molded article side and on the excess coating part side.

Description

Mold set for in-mold painting, and method for manufacturing in-mold painted parts

[0001] The present disclosure relates to a mold set for in-mold painting for producing a resin molded product with a paint film, which is an in-mold painted part, and a method for producing an in-mold painted part using the mold set.

[0002] Conventionally, when forming a paint film on a resin molded product, the resin molded product is formed by injection molding in a mold, and the resin molded product is then removed from the mold, and a paint is applied and dried. In contrast to this, an in-mold painting technique is known in which, after forming a resin molded product by injection molding in a mold, the cavity mold is changed and a paint film is formed in the mold (see, for example, Patent Document 1).

[0003] In in-mold painting, when injecting paint into the mold other than the product part (resin molded product), a paint injection gate (paint distribution channel) consisting of the primary resin and paint is required to allow the paint to flow into the cavity of the product part, and the area to be painted beyond the product part is required. In addition, after in-mold painting is completed, a separate cutting process is required to remove the paint injection gate and the area to be painted beyond the product part. This increases the number of processes, which increases manufacturing costs and has been a challenge in reducing the cost of in-mold painting.

[0004] Japanese Patent Application Laid-Open No. 2002-172657

[0005] The present disclosure aims to provide a mold set for in-mold painting that does not require a separate cutting process to remove areas to be painted beyond the paint injection gate and product area (excess paint area).

[0006] The in-mold coating mold set according to the present disclosure is a mold for a resin molded product, including a first core mold for forming a resin molded product and a cavity mold for the resin molded product, which, when the first core mold and the cavity mold for the resin molded product are clamped together, defines a cavity for the resin molded product, and also defines a cavity for a gate portion that serves as the base of a paint flow path from a paint injection port to the resin molding cavity when a paint film is formed, or a cavity for an auxiliary portion that serves as the base of an excess paint portion for flowing excess paint from an end of the cavity for the resin molded product when a paint film is formed, and a mold for a paint film, which includes a second core mold and a cavity mold for a paint film, for forming a paint film on the surface of the resin molded product. and a paint film mold that, when a resin molded product is placed on the second core mold and the second core mold and the paint film cavity mold are clamped together, defines a cavity for a paint flow path through which paint flows from the paint inlet to the resin molded product, or a cavity for an excess paint portion for flowing excess paint from the end of the resin molded product, wherein the distance between the second core mold and the paint film cavity mold at the boundary between the paint flow path and the resin molded product is narrower than the distance on the resin molded product side and the distance on the paint flow path side, and / or the distance between the second core mold and the paint film cavity mold at the boundary between the resin molded product and the excess paint portion is narrower than the distance on the resin molded product side and the distance on the excess paint portion side.

[0007] The method for manufacturing a resin molded product having a paint film according to the present disclosure includes a first mold clamping step of clamping a first core mold of a mold for a resin molded product and a cavity mold for a resin molded product to define a cavity for the resin molded product corresponding to the resin molded product and a cavity for a gate portion or a cavity for an auxiliary portion continuous with the cavity for the resin molded product; a resin introducing step of introducing resin into the cavity for the gate portion, the cavity for the resin molded product, and the cavity for the auxiliary portion to form the resin molded product and the gate portion or the auxiliary portion continuous with the resin molded product; a mold opening step of opening the first core mold and the cavity mold for the resin molded product to obtain the resin molded product and the gate portion or the auxiliary portion continuous with the resin molded product; and a mold opening step of placing the resin molded product and the gate portion and the auxiliary portion continuous with the resin molded product on a second core mold and clamping the second core mold and the cavity mold for a paint film to define a cavity for the paint film and a cavity for a paint distribution path continuous with the cavity for the paint film. or a second mold clamping step for defining a cavity for an excess paint portion for flowing continuous excess paint; a paint filling step for filling paint into the paint film cavity, the paint flow path cavity, and the excess paint portion cavity to form the paint film and the paint flow path or the excess paint portion; and a demolding step for opening the second core mold and the cavity mold for the paint film, pushing out a resin molded product having the paint film from the inside of the second core mold, and separating the resin molded product having the paint film from the paint flow path or the excess paint portion to obtain a resin molded product having a paint film, wherein the distance between the second core mold and the cavity mold for the paint film at the boundary between the paint flow path and the resin molded product is narrower than the distance on the resin molded product side and the distance on the paint flow path side, and / or the distance between the second core mold and the cavity mold for the paint film at the boundary between the resin molded product and the excess paint portion is narrower than the distance on the resin molded product side and the distance on the excess paint portion side.

[0008] According to the above-mentioned in-mold coating mold set, the boundary between the paint flow path and the resin molded product in the obtained resin molded product with a paint film is thinner than the paint flow path side and the resin molded product side, and / or the boundary between the resin molded product and the excess paint part is thinner than the resin molded product side and the excess paint part side. Therefore, when the resin molded product with a paint film is released from the mold, the paint flow path and the resin molded product can be separated, and the resin molded product can be separated from the excess paint part, without providing a separate process.

[0009] 1A is a partial enlarged view of the resin molded product of FIG. 1A ; FIG. 1B is a partial enlarged view of the die slide type resin molding die when forming a paint film; FIG. 2A is a partial enlarged view of the gap between the resin molded product and the paint film cavity die; FIG. 2B is a partial enlarged view of the die slide type paint film mold when starting to inject paint into the gap when forming a paint film; FIG. 3A is a partial enlarged view of the state when starting to inject paint into the gap between the resin molded product and the paint film cavity die; FIG. 3A is a partial enlarged view of the state when starting to inject paint into the gap between the resin molded product and the paint film cavity die; FIG. 4A is a partial enlarged view of the state after completing the injection of paint into the gap between the resin molded product and the paint film cavity die; 6A is a plan view (a) of a die-slide type mold for a paint film when it is released from the core mold after a paint film has been formed, and a schematic cross-sectional view (b) showing its cross-sectional structure. It is a partially enlarged view showing details of the resin molded body with a paint film of FIG. 5A when it is released from the core mold. It is a partially enlarged view showing the state before separation of the boundary portion 19a between the paint flow path 23 and the resin molded product 10. It is a plan view (a) of a die-slide type mold for a paint film when it is removed from the core mold after a paint film has been formed, and a schematic cross-sectional view (b) showing its cross-sectional structure. It is a partially enlarged view showing details of the resin molded body with a paint film of FIG. 6A when it is removed from the core mold. It is an in-mold coating mold set according to embodiment 2, and is a plan view (a) of a die-slide type mold for resin molding when it is forming a resin molded product, and a schematic cross-sectional view (b) showing its cross-sectional structure. It is a partially enlarged view of the resin molded product of FIG. 7A. It is a plan view (a) of a die-slide type mold for a paint film when it is forming a paint film, and a schematic cross-sectional view (b) showing its cross-sectional structure. 8A and 9A are partial enlarged views of a gap between the resin molded product and the cavity mold for a paint film, respectively; FIG. 9A is a plan view (a) and a schematic cross-sectional view (b) showing the cross-sectional structure at the start of paint injection into the gap of a die-slide type paint film mold during paint film formation; and FIG. 9B is a partial enlarged view of a state at the start of paint injection into the gap between the resin molded product and the cavity mold for a paint film, respectively;11B is a schematic cross-sectional view showing the cross-sectional structure of the die-slide type mold for a paint film after completion of injection of paint into the gap of the die-slide type mold for a paint film during formation of the paint film. 10A is a partially enlarged view showing the state after completion of injection of paint into the gap between the resin molded product and the cavity mold for a paint film in FIG. 10B. 11B is a partially enlarged view showing the cross-sectional structure of the die-slide type mold for a paint film during release from the core mold after formation of the paint film. 11C is a partially enlarged view showing the details of the resin molded product with a paint film of FIG. 11A during release from the core mold. 11D is a partially enlarged view showing the boundary between the paint flow path and the resin molded product. 11B is a schematic cross-sectional view showing the cross-sectional shape of the resin molded product with a paint film after formation of the paint film, including the paint flow path and the excess paint portion. 11B is a schematic cross-sectional view showing the cut of the paint flow path and the excess paint portion during release from the core mold. 11C is a front view of an LCD television. 13A is a schematic cross-sectional view showing the cross-sectional structure of the display exterior housing of the LCD television of FIG. 13A as viewed in the direction of line BB. 1 is an enlarged cross-sectional view showing a state in which a cavity for an excess coating portion is provided between an auxiliary portion and a cavity mold for a second coating film of an in-mold coating mold set according to a modified example of embodiment 2. FIG. 2 is a schematic cross-sectional view showing that unevenness is provided on the surface of the auxiliary portion.

[0010] The mold set for in-mold coating according to the first aspect is a mold for a resin molded product, which includes a first core mold for forming a resin molded product and a cavity mold for a resin molded product, and when the first core mold and the cavity mold for a resin molded product are clamped together, the mold for a resin molded product defines a cavity for the resin molded product, and also defines a cavity for a gate portion that serves as the base of a paint flow path from a paint injection port to the cavity for resin molding when a paint film is formed, or a cavity for an auxiliary portion that serves as the base of an excess paint portion for flowing excess paint from the end of the cavity for the resin molded product when a paint film is formed, and a mold for a paint film, which includes a second core mold and a cavity mold for a paint film, for forming a paint film on the surface of the resin molded product. and a paint film mold that, when a resin molded product is placed on the second core mold and the second core mold and the paint film cavity mold are clamped together, defines a cavity for a paint flow path through which paint flows from the paint inlet to the resin molded product, or a cavity for an excess paint portion for flowing excess paint from the end of the resin molded product, wherein the distance between the second core mold and the paint film cavity mold at the boundary between the paint flow path and the resin molded product is narrower than the distance on the resin molded product side and the distance on the paint flow path side, and / or the distance between the second core mold and the paint film cavity mold at the boundary between the resin molded product and the excess paint portion is narrower than the distance on the resin molded product side and the distance on the excess paint portion side.

[0011] The mold set for in-mold painting according to the second aspect is the first aspect, wherein the distance between the second core mold and the cavity mold for the paint film at the boundary between the paint distribution path and the resin molded product, or the distance between the second core mold and the cavity mold for the paint film at the boundary between the resin molded product and the excess paint portion, may be 0.05 mm or more and 1.2 mm or less.

[0012] The mold set for in-mold coating according to a third aspect is the mold set according to the first or second aspect, wherein the cavity of the excess coating portion may be provided in contact with the auxiliary portion.

[0013] The mold set for in-mold coating according to the fourth aspect is any one of the first to third aspects, in which the cavities of the auxiliary part may be provided from each of multiple ends of the cavity for the resin molded product.

[0014] The mold set for in-mold coating according to the fifth aspect is any one of the first to fourth aspects, in which the cavity of the excess coating portion may be provided at the end of the paint flow in the cavity of the resin molded product.

[0015] The mold set for in-mold painting according to the sixth aspect may be any of the first to fifth aspects, and may have a roll-in portion where the flow direction of the paint at the boundary between the paint flow path and the resin molded product, or at the boundary between the resin molded product and the excess paint portion, changes by 90 degrees or more with respect to the injection direction from the paint inlet.

[0016] The mold set for in-mold painting according to the seventh aspect may be any of the first to sixth aspects above, in which the first core mold and the second core mold are a common core mold, and the cavity mold for resin molding and the cavity mold for paint film are arranged so as to be mutually interchangeable at positions opposite the common core mold.

[0017] The mold set for in-mold coating according to an eighth aspect may be any of the first to seventh aspects, and may further include an ejector that, after the coating film has been formed, releases the resin molded product having the coating film layer from the second core mold, separates the paint flow path from the resin molded product at the boundary between the paint flow path and the resin molded product, and separates the resin molded product from the excess coating portion at the boundary between the resin molded product and the excess coating portion.

[0018] A method for producing a resin molded product having a coating film according to a ninth aspect includes a first mold clamping step of clamping a first core mold of a mold for a resin molded product and a cavity mold for a resin molded product to define a cavity for the resin molded product corresponding to the resin molded product and a cavity for a gate portion or a cavity for an auxiliary portion continuous with the cavity for the resin molded product; and a second mold clamping step of introducing resin into the cavity for the gate portion, the cavity for the resin molded product, and the cavity for the auxiliary portion to produce the resin molded product and the resin molded product. a resin introducing step of forming a gate portion or auxiliary portion continuous with the resin molded product; a mold opening step of opening the first core mold and the cavity mold for the resin molded product to obtain the resin molded product and the gate portion or auxiliary portion continuous with the resin molded product; a mold opening step of placing the resin molded product and the gate portion and auxiliary portion continuous with the resin molded product on the second core mold and clamping the second core mold and the cavity mold for the paint film to form a cavity for the paint film and a cavity or auxiliary portion for a paint distribution path continuous with the cavity for the paint film. the second core mold and the cavity mold for the paint film, and a cavity for the paint flow path and the cavity for the excess paint portion are filled with paint to form the paint film and the paint flow path or the excess paint portion; and a demolding process in which the second core mold and the cavity mold for the paint film are opened, the resin molded product having the paint film is pushed out from the inside of the second core mold, and the resin molded product having the paint film is separated from the paint flow path or the excess paint portion to obtain the resin molded product having the paint film, wherein the distance between the second core mold and the cavity mold for the paint film at the boundary between the paint flow path and the resin molded product is narrower than the distance on the resin molded product side and the distance on the paint flow path side, and / or the distance between the second core mold and the cavity mold for the paint film at the boundary between the resin molded product and the excess paint portion is narrower than the distance on the resin molded product side and the distance on the excess paint portion side.

[0019] Hereinafter, an in-mold coating mold set according to an embodiment will be described with reference to the accompanying drawings. Note that substantially the same components are designated by the same reference numerals.

[0020] (Embodiment 1) <In-mold coating mold set> FIG. 1A is an in-mold coating mold set 3 according to embodiment 1, showing a plan view (a) of a die-slide type resin molding mold when forming a resin molded product and a schematic cross-sectional view (b) showing the cross-sectional structure. FIG. 1B is a partial enlarged view of the resin molded product in FIG. 1A. FIG. 2A is a plan view (a) of a die-slide type paint film mold when forming a paint film and a schematic cross-sectional view (b) showing the cross-sectional structure. FIG. 2B is a partial enlarged view of the gap between the resin molded product 10 and the paint film cavity mold 7 in FIG. 2A. For convenience, in the drawings, the direction in which the first core mold 5 and the resin molded product cavity mold are opened is defined as the Z direction, and the horizontal direction of the X-Y plane perpendicular to this is defined as the X direction, and the direction extending from the front to the back of the page is defined as the Y direction. The in-mold coating mold set 3 according to embodiment 1 includes a resin molding mold for forming the resin molded product 10 and a mold for a paint film-coated resin molded product. The resin molding die includes a first core die 5 and a cavity die 6 for a resin molded product. When clamped, the first core die 5 and the cavity die 6 for a resin molded product define a cavity 10 for the resin molded product. Furthermore, they define a cavity for a gate portion 11 that serves as the base of a paint flow path from the paint inlet to the resin molding cavity when a paint film is formed, or a cavity for an auxiliary portion 12 that serves as the base of an excess paint portion for allowing excess paint to flow from the end of the cavity 10 for the resin molded product when a paint film is formed. The die for a resin molded product with a paint film includes a second core die 5 and a cavity die 7 for a paint film. A resin molded product 10 is placed on the second core mold 5, and when the second core mold 5 and the cavity mold 7 for the paint film are clamped together, a paint flow path is defined through which paint flows from the paint injection port 13 to the resin molded product 10, or a cavity for excess paint is defined to allow excess paint to flow from the end of the resin molded product.

[0021] The distance between the second core mold 5 and the cavity mold for a paint film at the boundary between the paint flow path and the resin molded product is set narrower than both the distance on the paint flow path side and the distance on the resin molded product side, and / or the distance between the second core mold 5 and the cavity mold for a paint film at the boundary between the resin molded product and the excess paint portion is set narrower than both the distance on the resin molded product side and the distance on the excess paint portion side. The distance between the second core mold 5 and the cavity mold for a paint film at the boundary 19a and / or the distance between the second core mold 5 and the cavity mold for a paint film 7 at the boundary 19b between the resin molded product 10 and the cavity 24 of the excess paint portion is, for example, 0.05 mm or more and 1.2 mm or less. According to the in-mold coating mold set of the first embodiment, the boundary between the paint flow path and the resin molded product or the boundary between the resin molded product and the excess paint portion in the obtained resin molded product with a paint film is thin. Therefore, when the painted resin molded article is released from the mold, the paint flow path and the resin molded article can be separated, and the resin molded article can be separated from the excess painted portion, without the need for a separate process.

[0022] The following describes the components that make up this in-mold coating mold set 3. The in-mold coating mold set 3 includes a mold for a resin molded product and a mold for a resin molded product with a paint film, and may be a die-slide type in-mold coating mold set in which a cavity mold 6 for a resin molded product and a cavity mold 7 for a paint film are slidably arranged relative to a common core mold, as shown in Figures 1A to 2B. Alternatively, although not shown, the in-mold coating mold set may be an out-mold type in-mold coating mold set in which a mold for a resin molded product and a mold for a resin molded product with a paint film are separately provided. While a die-slide type in-mold coating mold set will be described below, the present invention is not limited to this and may also be an out-mold type in-mold coating mold set.

[0023] <Mold for resin molded product> The mold for resin molding includes a first core mold 5 and a cavity mold for resin molded product 6. As shown in Fig. 1B, the first core mold 5 and the cavity mold for resin molded product 6, when clamped, define a cavity for a resin molded product corresponding to a resin molded product 10. Furthermore, they define a cavity for a gate portion 11 that serves as the base of a paint flow path from a paint inlet to the resin molding cavity when a paint film is formed, or a cavity for an auxiliary portion 12 that serves as the base of an excess paint portion for flowing excess paint from the end of the cavity for resin molded product when a paint film is formed.

[0024] 1B, the cavity mold 6 for a resin molded product is provided with a spool and runner gate 8 that branches off from the resin injection port 21 and serves as a resin path for guiding resin to the cavity for the resin molded product, the cavity of the gate portion 11, and the cavity of the auxiliary portion 12. The first core mold 5 and the cavity mold 6 for a resin molded product are each stored in a mold base 4.

[0025] <Mold for Paint Film> The mold for paint film includes a second core mold 5 and a cavity mold for paint film 7. In the die-slide type in-mold coating mold set 3 shown in Figures 1A to 2B, the second core mold 5 is the same core mold 5 as the first mold of the resin molding mold. In this case, when forming a paint film, a resin molded product 10, a gate portion 11 continuous with the resin molded product 10, and an auxiliary portion 12 are placed on the second core mold 5. In addition, a paint injection head 13 having a paint injection port 22 is attached to the cavity mold for paint film 7, and the paint injection port 22 is positioned so as to be close to the gate portion 11.

[0026] As shown in Fig. 2B , when the second core mold 5 and the paint film cavity mold 7 are clamped together, a paint film cavity 14 is formed between the resin molded product 10 and the paint film cavity mold 7. Furthermore, a paint flow path cavity 23 through which paint flows from the paint inlet 22 to the resin molded product 10, or an excess paint portion cavity 24 for allowing excess paint to flow from the end of the resin molded product, is defined. The paint flow path cavity 23 may be provided above the gate portion 11, and the excess paint portion cavity 24 may be provided above the auxiliary portion 12. Also, although Fig. 2B shows one excess paint portion cavity 24, multiple excess paint portion cavities may be provided. The distance between the second core mold 5 and the paint film cavity mold 7 at the boundary between the paint flow path and the resin molded product 10 is set narrower than both the distance on the paint flow path side and the distance on the resin molded product side, and / or the distance between the second core mold 5 and the paint film cavity mold 7 at the boundary between the resin molded product 10 and the excess paint portion is set narrower than both the distance on the resin molded product side and the distance on the excess paint portion side. The distance between the second core mold 5 and the paint film cavity mold 7 at the boundary portion 19a and / or the distance between the second core mold 5 and the paint film cavity mold 7 at the boundary portion 19b between the resin molded product 10 and the cavity 24 of the excess paint portion is, for example, 0.05 mm or more and 1.2 mm or less. Furthermore, the distance may be 0.1 mm or more and 0.8 mm or less.

[0027] <Method for manufacturing a resin molded article with a paint film (method for manufacturing an in-mold coated article)> The following describes a method for manufacturing a resin molded article with a paint film according to Embodiment 1. The method for manufacturing a resin molded article with a paint film includes a resin molded article formation step ( FIGS. 1A and 1B ), a paint film mold clamping step ( FIGS. 2A and 2B ), a paint injection step ( FIGS. 3A and 3B ), a curing step ( FIGS. 4A and 4B ), and a paint film-demolition step ( FIGS. 5A, 5B, 6A and 6B ).

[0028] <Process for Forming Resin Molded Product> The resin molded product is formed using a mold for a resin molded product in the in-mold coating mold set 3. Specifically, as shown in FIGS. 1A and 1B , a first core mold 5 and a cavity mold for a resin molded product 6 of the mold for a resin molded product are clamped together to define a cavity for a resin molded product corresponding to a resin molded product 10. Next, resin is introduced from a resin injection port 21 through a spool and a runner gate 8 into the cavity for the resin molded product 10, the cavity of the gate portion 11, and the cavity of the auxiliary portion 12. This forms the resin molded product 10, and the gate portion 11 and auxiliary portion 12 continuous with the resin molded product 10. After the resin hardens, the first core mold 5 and the cavity mold for a resin molded product 6 are opened to obtain the resin molded product 10, the gate portion 11, and auxiliary portion 12 continuous with the resin molded product 10.

[0029] 2A and 2B , when forming a paint film, a resin molded article 10, a gate portion 11 continuous with the resin molded article 10, and an auxiliary portion 12 are placed on the second core mold 5. A paint injection head 13 having a paint injection port 22 is attached to the paint film cavity mold 7, and the paint injection port 22 is positioned close to the gate portion 11. As shown in Fig. 2B , when the second core mold 5 and the paint film cavity mold 7 are clamped together, a paint film cavity 14 is formed between the resin molded article 10 and the paint film cavity mold 7. At the same time, a cavity 23 for a paint flow path through which paint flows from the paint injection port 22 to the resin molded article 10, and / or a cavity 24 for an excess paint portion for draining excess paint from the end of the resin molded article are defined. In this case, the distance between the second core mold 5 and the paint film cavity mold 7 at the boundary 19a between the paint flow path cavity 23 and the resin molded product 10 is set narrower than both the distance on the paint flow path side and the distance on the resin molded product side, and / or the distance between the second core mold 5 and the paint film cavity mold 7 at the boundary 19b between the resin molded product 10 and the cavity 24 of the excess paint portion is set narrower than both the distance on the resin molded product side and the distance on the excess paint portion side. The distance between the second core mold 5 and the paint film cavity mold 7 at the boundary 19a and / or the distance between the second core mold 5 and the paint film cavity mold 7 at the boundary 19b between the resin molded product 10 and the cavity 24 of the excess paint portion is set to, for example, 0.05 mm or more and 1.2 mm or less. Furthermore, the distance may be set to 0.1 mm or more and 0.8 mm or less.

[0030] <Paint Injection Process> Figure 3A is a plan view (a) and a schematic cross-sectional view (b) showing the cross-sectional structure at the start of paint injection into the gap of a die-slide type paint film mold during paint film formation. Figure 3B is a partial enlarged view of the state at the start of paint injection into the paint film cavity 14, which is the gap between the resin molded product 10 and the paint film cavity mold 7 in Figure 3A. As shown in Figure 3B, paint is introduced from the paint injection port 22 of the paint injection head 13 through the paint flow path cavity 23 into the paint film cavity 14. Any commonly used paint can be used. Furthermore, any commonly used paint injection head 13 can be used. The paint fills the paint flow path cavity 23 to form the paint flow path 23, and then fills the continuous paint film cavity 14 to form the paint film 14. The paint then reaches the continuous excess paint cavity 24 from the paint film cavity, forming the excess paint portion 24. Since the paint that reaches cavity 24 is excess paint, it is not necessary to fill cavity 24, and cavity 24 may be configured to have a sufficient capacity to receive excess paint. Also, by providing cavity 24 at the end of the paint flow, excess paint can be guided to cavity 24 that has been provided in advance, and unforeseen circumstances caused by excess paint can be avoided.

[0031] <Curing Process> Figure 4A is a plan view (a) and a schematic cross-sectional view (b) showing the cross-sectional structure after the paint has been completely injected into the gap of a die-slide type paint film mold during paint film formation. Figure 4B is a partially enlarged view of the state after the paint has been completely injected into the gap between the resin molded product and the paint film cavity mold in Figure 4A. As shown in Figure 4B, the paint filled in the paint flow path 23, the paint film 14, and the excess paint portion 24 is then cured. Note that the curing method is not limited to the above-mentioned method of allowing the paint to cure over time; it may also be cured by heating. Alternatively, a portion of the mold may be made of a transparent material and cured by irradiating it with ultraviolet light or the like.

[0032] <Mold Release Process of a Painted Resin Molded Product> Fig. 5A is a plan view (a) and a schematic cross-sectional view (b) showing the cross-sectional structure of a die-slide type paint film mold 3 when the paint film is formed and the molded product is released from the core mold. Fig. 5B is a partially enlarged view showing details of the painted resin molded product 16 of Fig. 5A when it is released from the core mold 5. Fig. 5C is a partially enlarged view showing the state before separation of the boundary portion 19a between the paint flow path 23 and the resin molded product 10. Fig. 6A is a plan view (a) and a schematic cross-sectional view (b) showing the cross-sectional structure of a die-slide type paint film mold 3 when it is removed from the core mold 5 after the paint film is formed. Fig. 6B is a partially enlarged view showing details of the painted resin molded product 16 of Fig. 6A when it is removed from the core mold 5. After the paint film 14 has hardened, the painted resin molded product (in-mold coated molded product) 16 is pushed up in the Z direction from the second mold 5 by a first ejector pin 17 provided inside the second mold 5 and released. At this time, the thickness of the boundary 19a between the paint flow path 23 and the resin molded product 10 is thinner than the thickness on the paint flow path side and the thickness on the resin molded product side. In other words, the boundary 19a has a constricted shape. Furthermore, the thickness of the boundary 19b between the resin molded product 10 and the excess paint portion 24 is thinner than the thickness on the resin molded product side and the thickness on the excess paint portion side. In other words, the boundary 19b has a constricted shape. For example, as described above, the thicknesses of the boundaries 19a and 19b are thin, ranging from 0.05 mm to 1.2 mm. In the case of FIG. 5C , the boundaries 19a and 19b include resin and the paint film 14a. However, this is not limited thereto and may include only the paint film. Therefore, the paint-coated resin molded product 16 can be separated from the paint flow path 23 and the excess paint portion 24 at the boundaries 19a and 19b by pushing it up with the first ejector pin 17. 5B shows the case where there are two first ejector pins 17, but the present invention is not limited to this and may have one or three or more first ejector pins 17. The first ejector pins 17 may be driven by any commonly used method, such as hydraulic, pneumatic, or mechanical drive.

[0033] 6A and 6B, the gate portion 11 and the paint flow path 23, and the auxiliary portion 12 and the excess coating portion 24 are pushed up from the second mold 5 by the second ejector pins 18 provided in the second mold 5 and released from the mold. While Fig. 6B shows a case where there is one first ejector pin 18 for each mold, the present invention is not limited to this and two or more first ejector pins may be provided. The second ejector pins 18 may be driven by any commonly used method, such as hydraulic, pneumatic, or mechanical drive.

[0034] (Embodiment 2) <In-mold coating mold set> Figure 7A is an in-mold coating mold set 3a according to embodiment 2, and is a plan view (a) of a die-slide type resin molding mold when forming a resin molded product 10, and a schematic cross-sectional view (b) showing the cross-sectional structure. Figure 7B is a partial enlarged view of the resin molded product 10 in Figure 7A. Figure 8A is a plan view (a) of a die-slide type paint film mold when forming a paint film, and a schematic cross-sectional view (b) showing the cross-sectional structure. Figure 8B is a partial enlarged view of the gap between the resin molded product 10 and the paint film cavity in Figure 8A. The in-mold coating mold set 3a according to the second embodiment differs from the in-mold coating mold set according to the first embodiment in that it has a roll-up portion in which the paint flow direction 20b ( FIG. 9B ) at the boundary 19a between the paint flow path 23 and the resin molded product 10 or at the boundary 19b between the resin molded product 10 and the excess paint portion 24 changes by 90 degrees or more relative to the injection direction 20a ( FIG. 9B ) from the paint inlet 22. To form this roll-up portion, the mold for the resin molded product of the in-mold coating mold set 3a further includes second resin molded product cavity molds 9a, 9b that are movable separately from the resin molding cavity mold 6 of the mold for the resin molded product. This forms the roll-up portions of the gate portion 11 and auxiliary portion. Furthermore, the mold for the paint film further includes second paint film cavity molds 15a, 15b that are movable separately from the paint film cavity mold 7. This forms a paint flow path 23 and a wrap-up portion for excess paint portion 24.

[0035] <Method of manufacturing a resin molded product with a paint film (method of manufacturing an in-mold coated product)> Compared to the method of manufacturing a resin molded product with a paint film according to the second embodiment, this method differs in that a resin molded product 10 is formed using second resin molded product cavity molds 9a, 9b that are movable separately from the resin molding cavity mold 6 of the mold for the resin molded product. Furthermore, it differs in that a paint film 14 is formed using second paint film cavity molds 15a, 15b that are movable separately from the paint film cavity mold 7.

[0036] <Process for Forming Resin Molded Product> The resin molded product is formed using the resin molded product mold of the in-mold coating mold set 3a. Specifically, as shown in Figures 7A and 7B, the first core mold 5 of the resin molded product mold, the resin molded product cavity mold 6, and the second resin molded product cavity molds 9a and 9b are clamped together to define a resin molded product cavity corresponding to the resin molded product 10. Next, resin is introduced from the resin injection port 21 through the spool and runner gate 8 into the resin molded product cavity 10, the cavity of the gate portion 11, and the cavity of the auxiliary portion 12. This forms the resin molded product 10, and the gate portion 11 and auxiliary portion 12 continuous with the resin molded product 10. After the resin hardens, the first core mold 5, the cavity mold 6 for the resin molded product, and the cavity molds 9a and 9b for the second resin molded product are opened to obtain the resin molded product 10, as well as the gate portion 11 and auxiliary portion 12 continuous with the resin molded product 10. After first opening the first core mold 5 and the cavity mold 6 for the resin molded product, the cavity molds 9a and 9b for the second resin molded product are slid in the direction perpendicular to the paper surface (Y direction) to remove them. The thickness of the obtained resin molded product 10 may have a lower limit of 1 mm or more, 2 mm or more, or an upper limit of 5 mm or less, or even 4 mm or less. The thickness of the auxiliary portion 12 may be equal to or thinner than the thickness of the resin molded product 10. The resin molded product 10, the gate portion 11, and the auxiliary portion 12 are not limited to being continuous as described above, but may be individually separated.

[0037] 8A and 8B , when forming a paint film, a resin molded article 10, a gate portion 11 continuous with the resin molded article 10, and an auxiliary portion 12 are placed on the second core mold 5. A paint injection head 13 having a paint injection port 22 is attached to the paint film cavity mold 7, and the paint injection port 22 is positioned close to the gate portion 11. As shown in Fig. 8B , when the second core mold 5, the paint film cavity mold 7, and the second paint film cavity molds 15a, 15b are clamped together, a paint film cavity 14 is formed between the resin molded article 10 and the paint film cavity mold 7. At the same time, a cavity 23 for a paint flow path through which paint flows from the paint injection port 22 to the resin molded article 10, and / or a cavity 24 for an excess paint portion for flowing excess paint from the end of the resin molded article are defined. In this case, the distance between the second core mold 5 and the cavity mold 7 for the paint film at the boundary 19a between the cavity 23 of the paint flow path and the resin molded product 10, and / or the distance between the second core mold 5 and the cavity mold 7 for the paint film at the boundary 19b between the resin molded product 10 and the cavity 24 for the excess paint portion, is set to 0.05 mm or more and 1.2 mm or less. Furthermore, the distance may be set to 0.1 mm or more and 0.8 mm or less.

[0038] <Paint Injection Process> Figure 9A is a plan view (a) and a schematic cross-sectional view (b) showing the cross-sectional structure at the start of paint injection into the gap of a die-slide type paint film mold during paint film formation. Figure 9B is a partial enlarged view of the state at the start of paint injection into the paint film cavity 14, which is the gap between the resin molded product 10 and the paint film cavity mold 7 in Figure 9A. As shown in Figure 9B, paint is introduced from the paint injection port 22 of the paint injection head 13 through the paint flow path cavity 23 into the paint film cavity 14. The paint fills the paint flow path cavity 23 to form the paint flow path 23, and then fills the continuous paint film cavity 14 to form the paint film 14a. The paint then reaches the continuous excess paint cavity 24 from the paint film cavity, forming the excess paint portion 24. Since the paint that reaches cavity 24 is excess paint, it is not necessary to fill cavity 24, and cavity 24 may be configured to have a sufficient capacity to receive excess paint. Also, by providing cavity 24 at the end of the paint flow, excess paint can be guided to cavity 24 that has been provided in advance, and unforeseen circumstances caused by excess paint can be avoided.

[0039] <Curing Process> Fig. 10A is a plan view (a) and a schematic cross-sectional view (b) showing the cross-sectional structure after the paint has been poured into the gap of a die-slide type paint film mold during paint film formation. Fig. 10B is a partially enlarged view of the state after the paint has been poured into the gap between the resin molded product and the paint film cavity in Fig. 10A. As shown in Fig. 10B, the paint filled in the paint flow path 23, the paint film 14a, and the excess paint portion 24 is then cured. Note that the curing method is not limited to the above-described method of curing by the passage of time, and curing by heating may also be performed. Alternatively, a portion of the mold may be made of a transparent material and cured by irradiating ultraviolet light or the like.

[0040] <Mold release process of a resin molded article with a coating film> Figure 11A is a plan view (a) of a die-slide type mold for a coating film when the resin molded article is released from the core mold after the coating film is formed, and a schematic cross-sectional view (b) showing the cross-sectional structure. Figure 11B is a partial enlarged view showing details of the resin molded article 16 with a coating film of Figure 11A when it is released from the core mold 5. Figure 11C is a partial enlarged view of a boundary portion 19a between the paint flow path 23 and the resin molded article 10. After the coating film 14 has hardened, the cavity mold 7 for a coating film and the second core mold 5 are opened, and then the resin molded article with a coating film (in-mold coated molded article) 16 is pushed up in the Z direction from the second mold 5 by a first ejector pin 17 provided inside the second mold 5 and released. As shown in FIG. 11C , the thickness of the boundary 19a between the paint flow path 23 and the resin molded product 10 and the boundary 19b between the resin molded product 10 and the excess paint portion 24 are thin, e.g., 0.05 mm or more and 1.2 mm or less, as described above. Therefore, the paint-coated resin molded product 16 can be separated from the paint flow path 23 and the excess paint portion 24 at the boundaries 19a, 19b by pushing up in the Z direction with the first ejector pins 17. While FIG. 11B illustrates the case where two first ejector pins 17 are used, this is not limiting and one or three or more first ejector pins may be used. The first ejector pins 17 may be driven by any commonly used method, such as hydraulic, pneumatic, or mechanical drive. The second paint film cavity molds 15a, 15b can be slid in the Y direction and removed. This allows the paint flow path 23 and the excess paint portion 24 to be removed from the second core mold 5.

[0041] <Regarding Cutting of Boundary Portions That Are Roll-Up Portions> Fig. 12A is a schematic cross-sectional view showing a cross-sectional shape including the coated resin molded article 16 after the coating film has been formed in Fig. 10B , the paint flow path 23, and the excess coating portion 24. Fig. 12B is a schematic cross-sectional view showing the cutting of the paint flow path 23 and the excess coating portion 24 when the coated resin molded article 16 is released from the core mold 5 in Fig. 11B . As shown in Fig. 12A , the coated resin molded article 16 includes the continuous paint flow path 23 and the excess coating portion 24. In the conventional method, a separate separation step was required after release from the core mold 5, as shown in Fig. 12B . In the method for manufacturing the coated resin molded article 16 according to the second embodiment, the paint flow path 23 and the excess coating portion 24 can be separated simultaneously when the coated resin molded article 16 is released from the second core mold 5, as shown in Fig. 11B . This is achieved by providing the paint flow path 23 and the excess paint portion 24 extending from the coated resin molded article 16 in the Z direction (Z direction) along the direction in which the coated resin molded article 16 is released from the second core mold 5. In other words, by using the first ejector pin 17 to push up the coated resin molded article 16 in the Z direction for release, the boundaries 19a, 19b between the coated resin molded article 16 and the paint flow path 23 and the excess paint portion 24, which extend in the Z direction, are thin, and therefore the boundaries 19a, 19b are cut, allowing the paint flow path 23 and the excess paint portion 24 to be separated. The above steps result in a coated resin molded article 16. In this coated resin molded article 16, the thickness of the resin molded article 10 may have a lower limit of 1 mm or more, or 2 mm or more. The upper limit may be 5 mm or less, or even 4 mm or less. The thickness of the coating film 14a may have a lower limit of, for example, 0.01 mm or more, 0.05 mm or more, or 0.1 mm or more. The upper limit may be 1 mm or less, 0.5 mm or less, or 0.2 mm or less. The thickness of the resin molded product and the thickness of the coating film 14a do not have to be uniform. There may be portions where the thickness exceeds the above range. The boundaries 19a and 19b may not have resin, and may have only the coating film.

[0042] <Application: Display Exterior Housing> Fig. 13A is a front view of an LCD television. Fig. 13B is a schematic cross-sectional view showing the cross-sectional structure of the display exterior housing 2 of the LCD television of Fig. 13A as viewed in the direction of line BB. The coated resin molded product 16 according to embodiment 2 can be combined with a monitor 20 to form the display exterior housing 2. The boundaries 19a and 19b separating the paint flow path 23 and the excess paint portion 24 can be covered by the monitor 20 and can be hidden from view. In other words, the boundaries 19a and 19b can be positioned so that they can be covered by the monitor.

[0043] <Spacing of Cavities for Excess Paint Portion> Figure 14 is an enlarged cross-sectional view showing a cavity 24 for an excess paint portion provided between the auxiliary portion 12 and the second paint film cavity mold 15b of an in-mold coating mold set according to a modified example of embodiment 2. Figure 14 is an enlarged view of a modified example of the cavity for the excess paint portion shown in Figure 9B. As shown in Figure 14, when a roll-up portion is provided at the paint flow end, it is necessary to use a second paint film cavity mold 15b that can move separately from the paint film cavity mold 7. In this case, paint may leak from the flow end of the second paint film cavity mold 15b. As shown in Figure 14, in the in-mold coating mold set according to a modified example of embodiment 2, a cavity 24 for an excess paint portion is provided at the paint flow end to serve as a paint reservoir for flowing excess paint into the second paint film cavity mold 15b. In this case, the distance B between the second paint film cavity mold 15b and the cavity 24 for the excess paint portion is larger than the distance A between the second paint film cavity mold 15b and the auxiliary portion 12 along the paint path. Specifically, the distance A is 0.005 mm or more and 0.2 mm or less, and the distance B is at least twice the distance A, for example, 0.01 mm or more and 0.4 mm or less. Furthermore, the distance B may be five times the distance A or more. This allows the excess paint to accumulate in the excess paint portion 24, thereby preventing paint leakage. Note that, as shown in FIG. 14 , the distance A may also be provided beyond the cavity 24 for the excess paint portion. Alternatively, the excess paint portion cavity 24 may be provided continuously to the end of the second paint film cavity mold 15b.

[0044] <Surface of Excess Paint Portion> Figure 15 is a schematic cross-sectional view showing that unevenness 26 is provided on the surface of the auxiliary part 12. As shown in Figure 15, the surface of the auxiliary part 12 may be provided with unevenness 26. Since the surface of the auxiliary part 12 has unevenness 26, excess paint tends to remain on the surface of the auxiliary part 12 and is less likely to adhere to the cavity mold 15b for the second paint film when the excess paint portion 24 is formed.

[0045] The in-mold coating mold set according to the present disclosure can separate the paint flow path from the resin molded product and the excess paint from the resin molded product at the same time as releasing the coated resin molded product without any additional process steps, making it suitable for use in, for example, the exterior housing of a display.

[0046] DESCRIPTION OF SYMBOLS 1 Display 2 Display exterior housing 3, 3a Die slide type in-mold coating mold (mold set) 4 Mold base 5 Core mold (first core mold, second core mold) 6 Cavity mold for resin molded product 7 Cavity mold for paint film 8 Spool, runner gate 9a, 9b Cavity mold for second resin molded product (slide mold for resin molded product) 10 Resin molded product (product part, cavity for resin molded product) 11 Gate part (paint injection gate) 12 Auxiliary part (resin) 13 Paint injection head 14 Paint injection clearance (cavity for paint film) 14a Paint film 15a, 15b Cavity mold for second paint film (slide mold for paint film) 16 In-mold coated molded product (resin molded product with paint film) 17 First ejector pin 18 Second ejector pin 19a Boundary between paint flow path and resin molded product 19b Boundary between resin molded product and excess paint area 20 Monitor 21 Resin injection port 22 Paint injection port 23 Paint flow path (cavity) 24 Excess paint area (cavity) 26 Unevenness

Claims

1. A mold for a resin molded product, comprising a first core mold for forming a resin molded product and a cavity mold for the resin molded product, wherein when the first core mold and the cavity mold for the resin molded product are clamped together, the mold for a resin molded product defines a cavity for the resin molded product, and also defines a cavity for a gate portion that serves as the base of a paint flow path from a paint inlet to the resin molding cavity when a paint film is formed, or a cavity for an auxiliary portion that serves as the base of an excess paint portion for flowing excess paint from the end of the cavity for the resin molded product when a paint film is formed; and a paint film mold including a second core mold and a paint film cavity mold for forming a paint film on the surface of the resin molded product, wherein when the resin molded product is placed on the second core mold and the second core mold and the paint film cavity mold are clamped together, the paint film mold defines a cavity for a paint flow path through which paint flows from a paint inlet to the resin molded product, or a cavity for an excess paint portion through which excess paint can flow from an end of the resin molded product, wherein the distance between the second core mold and the paint film cavity mold at the boundary between the paint flow path and the resin molded product is narrower than the distance on the resin molded product side and the distance on the paint flow path side, and / or the distance between the second core mold and the paint film cavity mold at the boundary between the resin molded product and the excess paint portion is narrower than the distance on the resin molded product side and the distance on the excess paint portion side.

2. A mold set for in-mold painting as described in claim 1, wherein the distance between the second core mold and the cavity mold for the paint film at the boundary between the paint flow path and the resin molded product, or the distance between the second core mold and the cavity mold for the paint film at the boundary between the resin molded product and the excess paint portion, is 0.05 mm or more and 1.2 mm or less.

3. The in-mold coating mold set according to claim 1, wherein the cavity of the excess coating portion is provided in contact with the auxiliary portion.

4. A mold set for in-mold coating according to claim 1, wherein the auxiliary cavity is provided from each of a plurality of ends of the cavity for the resin molded product.

5. A mold set for in-mold coating according to claim 4, wherein the cavity for the excess coating portion is provided at the end of the paint flow of the cavity for the coating film.

6. A mold set for in-mold coating as described in claim 1, which has a roll-up section where the flow direction of the paint at the boundary between the paint flow path and the resin molded product, or at the boundary between the resin molded product and the excess paint area, changes by 90 degrees or more with respect to the injection direction from the paint inlet.

7. A mold set for in-mold coating as described in claim 1, wherein the first core mold and the second core mold are a common core mold, and the cavity mold for resin molding and the cavity mold for paint film are arranged so as to be mutually interchangeable at positions opposite the common core mold.

8. A mold set for in-mold painting as described in claim 1, further comprising an ejector that, after the paint film is formed, releases the resin molded product having the paint film layer from the second core mold, separates the paint flow path from the resin molded product at the boundary between the paint flow path and the resin molded product, and separates the resin molded product from the excess paint portion at the boundary between the resin molded product and the excess paint portion.

9. A first mold clamping process in which a first core mold of a mold for a resin molded product and a cavity mold for a resin molded product are clamped together to define a cavity for the resin molded product corresponding to the resin molded product and a gate portion cavity or an auxiliary portion cavity continuous with the cavity for the resin molded product; a resin introduction process in which resin is introduced into the gate portion cavity, the cavity for the resin molded product, and the auxiliary portion cavity to form the resin molded product and the gate portion or auxiliary portion continuous with the resin molded product; and a mold opening process in which the first core mold and the cavity mold for the resin molded product are opened to obtain the resin molded product and the gate portion or auxiliary portion continuous with the resin molded product. the second core mold and the paint film cavity mold are clamped together to define a cavity for a paint film, a cavity for a paint flow path continuous with the cavity for the paint film, or a cavity for an excess paint portion for flowing excess paint; a paint filling step to fill the cavity for the paint film, the cavity for the paint flow path, and the cavity for the excess paint portion with paint to form a paint film and the paint flow path or the excess paint portion; and a demolding step to open the second core mold and the paint film cavity mold, push out the resin molded product having the paint film from inside the second core mold, and separate the resin molded product having the paint film from the paint flow path or the excess paint portion, thereby obtaining the resin molded product having the paint film, A method for manufacturing a resin molded product having a paint film, wherein the distance between the second core mold and the cavity mold for the paint film at the boundary between the paint flow path and the resin molded product is narrower than the distance on the resin molded product side and the distance on the paint flow path side, and / or the distance between the second core mold and the cavity mold for the paint film at the boundary between the resin molded product and the excess paint part is narrower than the distance on the resin molded product side and the distance on the excess paint part side.

Images