JP2010221609A - Mold for in-mold coating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for in-mold coating which prevents a coating material from flowing to the back side of a resin product when an in-mold coating method is executed. <P>SOLUTION: In the mold 6 for in-mold coating which forms a cavity 12 by a mold 7 on the surface side of the resin product and a mold 8 on the back side of the resin product, molds the resin product 1 by injecting a molten resin 14 into the cavity 12, and coats the surface 1a of the resin product 1 with a coating material 3, a recess 15 is formed in the peripheral part of the mold 8 on the back side of the resin product which forms a cavity 12a facing a coating material 3 injection part 5, and a coating material 3 sealing part is formed in which a resin 14 which is molded by the recess 15 and the cavity 12a and shrunk adheres to the mold 8 on the back side of the resin product and the mold 7 on the surface side of the resin product and flows to the back 1b side of the resin product 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an in-mold coating mold having a structure that prevents a coating material from flowing out to the back side of a resin product when an in-mold coating method is performed.

An auxiliary cavity communicated with the main cavity formed by the fixed mold and the movable mold is provided, and the central region of the auxiliary cavity has a boundary between the resin injected into the main cavity and the mold surface of the main cavity, or A coating material injection part is provided for injecting coating material into the space formed between the resin injected into the main cavity and the mold surface of the main cavity, and the coating material in the end area of the auxiliary cavity is injected. There is known a mold in which a groove for preventing outflow of a coating material is provided on a mold surface on the side to be processed (see, for example, Patent Document 1).

JP-A-8-309789

However, in the technique described in Patent Document 1, a groove for preventing the outflow of the coating material is provided, but sufficient leakage of the coating material cannot be prevented due to the resin shrinkage and the injection pressure of the coating material in the groove. There is a problem.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to discharge the coating material to the back side of the resin product when performing the in-mold coating method. It is an object of the present invention to provide a mold for in-mold coating that prevents this.

In order to solve the above problems, the present invention forms a cavity by using a mold on the front side of a resin product and a mold on the back side of the resin product, and injects molten resin into the cavity to mold the resin product. In a mold for in-mold coating in which a coating material is coated on the surface of a product, a recess is provided in the peripheral portion of the mold on the back side of the resin product that forms a cavity facing the injection portion of the coating material. The molded and shrunk resin is in close contact with the mold on the back side of the resin product and the mold on the front side of the resin product to form a sealing portion of the covering material that flows out to the back side of the resin product.

The relationship between the depth t2 of the recess and the depth t1 of the cavity adjacent to the recess is preferably 0.01t1 ≦ t2 ≦ t1.

According to the present invention, even in the vicinity of the injection portion of the coating material having a high injection pressure, the adhesion between the contracted resin and the mold is maintained, and the coating material is prevented from flowing out to the back side of the resin product. be able to. Further, since the covering material does not flow into unnecessary portions, the covering material does not become insufficient at the terminal portion of the resin product.

Further, if the relationship between the depth t2 of the recess and the depth t1 of the cavity adjacent to the recess is set to 0.01 t1 ≦ t2 ≦ t1, the mold on the back side of the resin product made of the contracted resin and the resin product Adhesive strength to the surface side mold can be obtained.

The perspective view of the resin product shape | molded by the metal mold | die for in-mold | coating which concerns on this invention Sectional view of the mold for in-mold coating according to the present invention Illustration of forming the tongue Explanation of the recess Illustration of in-mold coating method Illustration of in-mold coating method Action diagram of tongue It is explanatory drawing of various recessed parts and a tongue part, (a) is a recessed part substantially trapezoid shape, (b) is a rectangular shape in which a recessed part has a gradient, (c) is the terminal shape of a tongue part.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The resin product 1 to be applied with in-mold coating is assumed to have a box shape and a concave shape 2 at the center as shown in FIG. The surface 1 a of the resin product 1 is coated with a coating material 3. Reference numeral 4 denotes a tongue portion to which a coating material injection portion 5 for coating the coating material 3 on the surface 1a of the resin product 1 is connected. Since the tongue 4 is not included in the resin product 1, the tongue 4 is removed after the surface 1 a of the resin product 1 is coated with the coating material 3.

As shown in FIG. 2, the in-mold coating mold 6 according to the present invention is a mold for performing an in-mold coating method. The mold 7 on the front side of the resin product, and the mold 8 on the back side of the resin product. , A sprue 9, a covering material injection portion 5 for injecting the covering material 3, a runner, a gate (not shown), and the like. A cavity 12 for molding the resin product 1 is formed by the mold 7 on the front side of the resin product and the mold 8 on the back side of the resin product. Reference numeral 13 denotes a nozzle of an injection molding machine that supplies the molten resin 14 to the sprue 9.

Moreover, as shown in FIG. 3, the recessed part 15 is provided in the peripheral part of the metal mold | die 8 of the back surface side of the resin product which forms the cavity 12a which faces the coating | coated material injection | pouring part 5. As shown in FIG. The tongue 4 formed by the recess 15 and the cavity 12a is in close contact with the mold 8 on the back surface side of the resin product and the mold 7 on the surface side of the resin product, and flows out to the back surface 1b side of the resin product 1. The seal part of the material 3 is formed. The tongue 4 includes a plate-like portion 4a formed by the cavity 12a and a resin convex portion 4b formed by the concave portion 15. In addition, the tongue part 4 shown in FIG. 3 is represented by the AA line cross section of FIG.

As shown in FIG. 4, the recess 15 provided in the peripheral portion of the mold 8 on the back side of the resin product has a substantially semicircular cross section, and is adjacent to the depth t <b> 2 of the recess 15 and the recess 15, and the plate-like portion 4 a. It is preferable to set the relationship with the depth t1 of the cavity 12a for molding the material to 0.01t1 ≦ t2 ≦ t1.

The operation of the in-mold coating mold 6 according to the present invention configured as described above will be described. As shown in FIG. 5, the in-mold coating mold 6 includes a cavity 12 formed by a mold 7 on the front surface side of the resin product and a mold 8 on the back surface side of the resin product. Resin product 1 is molded by injecting molten resin 14 supplied from nozzle 13 through sprue 9.

Next, in the in-mold coating die 6, after molding the resin product 1, as shown in FIG. 6, the coating material 3 is poured from the coating material injection portion 5 into the gap 16 formed by the resin product 1 and the cavity 12. The coating material 3 is coated on the surface (design surface) 1 a of the resin product 1. At this time, the covering material 3 tends to face the back surface 1 b side of the resin product 1.

  However, as shown in FIG. 7, the resin convex portion 4 b formed by the concave portion 15 due to the contraction of the resin 14 in the direction of arrow A is detached from the concave portion 15 and rides on the mold 8 on the back side of the resin product. Then, the plate-like portion 4a formed by the cavity 12a presses the mold 7 on the surface side of the resin product in the arrow B direction. Therefore, the tongue part 4 which consists of the plate-shaped part 4a and the resin convex part 4b closely_contact | adheres to the metal mold | die 7 on the surface side of a resin product, and the metal mold | die 8 on the back surface side of a resin product.

Due to the behavior of the resin convex portion 4b and the plate-like portion 4a, the tongue portion 4 is in close contact with the mold 7 on the front surface side of the resin product and the mold 8 on the back surface side of the resin product. Even in the vicinity of the injection portion 5, the covering material 3 can be prevented from flowing out to the back surface 1 b side of the resin product 1, and the covering material 3 does not become insufficient at the terminal portion of the resin product 1.

Further, even if the adhesion force of the coating material injection portion (the plate-like portion 4a and the mold 7 on the surface side of the resin product) is reduced due to the injection pressure of the coating material 3, the resin convex portion 4b in the direction of arrow B and the resin Since the adhesion force of the mold 8 on the back surface side of the product is further increased by the injection pressure of the covering material 3, it is possible to reliably prevent the covering material 3 from flowing out to the back surface 1 b side of the resin product 1.

As the shape of the recess 15, the cross section shown in FIG. 4 may be a substantially semicircular shape, the cross section shown in FIG. 8A may be a substantially trapezoidal shape, or the cross section shown in FIG. Shape may be sufficient. Moreover, the terminal shape of the tongue part 4 does not depend on the shape as shown in FIG.

According to the present invention, when the in-mold coating method is performed, the coating material can flow out to the back side of the resin product, and the mold can be easily processed, thereby contributing to cost reduction. A mold can be provided.

DESCRIPTION OF SYMBOLS 1 ... Resin product, 1a ... Front surface, 1b ... Back surface, 3 ... Coating | covering material, 4 ... Tongue part, 4a ... Plate-shaped part, 4b ... Resin convex part, 5 ... Coating material injection | pouring part, 6 ... In-mold coating metal mold | die 7 ... Mold on the front side of the resin product, 8 ... Mold on the back side of the resin product, 9 ... Sprue, 12, 12a ... Cavity, 13 ... Nozzle of the injection molding machine, 14 ... Molten resin, 15 ... Recess, 16 ... Gap.

Claims (2)

A mold that forms a cavity with a mold on the front side of the resin product and a mold on the back side of the resin product, injects molten resin into the cavity, molds the resin product, and coats the surface of the resin product with a coating material In the inner coating mold, a recess is provided in the peripheral portion of the mold on the back side of the resin product that forms a cavity facing the injection portion of the coating material, and the resin that is molded and contracted by the recess and the cavity is the back surface of the resin product. An in-mold coating mold characterized in that a sealing portion of a covering material that flows out to the back side of a resin product is formed in close contact with the side mold and the mold on the surface side of the resin product. 2. The mold for in-mold coating according to claim 1, wherein the relationship between the depth t2 of the recess and the depth t1 of the cavity adjacent to the recess is 0.01t1 ≦ t2 ≦ t1. Mold for inner coating.