JP2012116021A - Mold for in-mold coating and in-mold coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for in-mold coating and an in-mold coating method preventing generation of burrs of a coating material at an opening edge on a coating face (design face) side, capable of preventing a resin molded product from embracing a mold on the coating face side during mold opening and preventing deformation of the resin molded product during product extrusion.SOLUTION: In the mold for in-mold coating, a projection for forming a penetrating opening on the resin molded product which is molded by injecting and filling molten resin in a mold cavity formed by combining a first mold and a second mold having a coating material injector with each other is formed so as to project to a mold opening/closing direction. The projection for forming the opening is formed by making a first projection formed in the first mold on a non-coating face side of the resin molded product and a second projection formed in the second mold on the coating face side to oppose to the first projection abut on each other.

Description

  The present invention relates to an in-mold coating mold and an in-mold coating method in which a resin molded product is molded in a mold, and then the surface of the resin molded product is coated with a paint or the like without removing the resin molded product from the mold. About.

  As a method for improving the decorativeness of a resin molded product, decoration by a coating method in which a paint is applied to the surface is often used. The conventional coating method is to apply a paint to the surface of a resin molded product by spraying or dipping after the resin molded product that has been injection molded in the mold is removed from the mold. The applied paint is then dried and cured to form a strong coating film, covering the surface of the resin molded product, decorating and protecting the surface.

  In recent years, for the purpose of simplifying the steps of the coating method, molding of a resin molded product and coating with a paint are performed in the same mold (also referred to as in-mold coating molding method, so-called in-mold). Coating.) Has been proposed. In this method, after the resin molded product is injection-molded in the mold, the mold is slightly opened (micro mold open), so that the resin molded product is placed between the resin molded product and the mold cavity surface in the mold. Create a gap. Then, after a paint is injected into the gap using a paint injection machine, the mold is clamped again to uniformly extend the surface of the resin molded product, and then cured to perform coating.

  According to the in-mold coating method, since the molding of the resin molded product and the coating are performed in the same mold, the cost can be reduced by omitting the process. At the same time, the dust floating in the air hardly adheres to the coating film before curing and becomes defective, and a high quality product can be obtained. Therefore, in particular, the use of the in-mold coating method has been studied for automobile parts and the like that require high quality for appearance. However, there are the following problems when forming an opening that penetrates the resin molded product, such as a screw hole for fixing the resin molded product to another component with a screw or the like, or an insertion hole for inserting another component. there were.

  When the opening is formed as described above, it projects in the mold opening / closing direction on one of the mold on the non-painted surface (non-design surface) side or the mold on the painted surface (design surface) side. It is common to form a convex part on the other mold and abut against the other mold, or to provide a concave part on the other mold and insert the previous convex part into the concave part. However, when the convex part is formed on the mold on the non-coating surface side, the mold is opened slightly to inject the paint, so that the gap between the tip of the convex part and the mold on the coating surface side However, there was a problem that a gap into which the paint entered was generated, and a paint burr was formed at the end of the opening on the painted surface side.

  Also, when the convex part is formed on the painted surface side of the mold, the above-mentioned problem can be solved, but in order to inject the paint, the mold on the painted surface side is separated from the mold on the non-coated surface side. By opening the micro mold, the convex part, which is generally provided with a draft angle in the mold opening / closing direction, is moved in the mold opening / closing direction with respect to the resin molded product held in the mold on the non-coating surface side, There was a problem that a gap was also generated between the convex portion and the opening of the resin molded product formed by the convex portion, and the paint leaked to the mold on the non-painted surface side through the gap. . (Refer to FIG. 8 and FIG. 9 in Patent Document 1 to be described later) This paint leakage causes a short shot of the paint, which deteriorates the quality of the painted surface, or the leaked paint is applied to the mold on the non-painted surface side. Factors that hinder continuous operation, such as causing troubles or periodic cleaning of molds, because they enter into the extrusion pins and other sliding parts of the placed product extrusion means and harden and accumulate. It was.

  In order to solve this problem, Patent Document 1 discloses that a convex portion for forming an opening is provided on a mold on the coated surface side of a base resin constituting a resin molded product, and A part thereof has a seal portion, and the seal portion is formed in a portion that comes into contact with the non-painted surface of the base resin on which the projection is injection-molded, and is in contact with the resin constituting the molded product. Disclosed is an in-mold coating mold in which the contact surface of the part is formed so as to be substantially parallel to the opening and closing direction of the mold, and an in-mold coating method using these molds. With this mold and coating method, when the mold is opened for injecting the paint, the convex portion is relatively in the mold opening / closing direction with respect to the resin constituting the molded product. Resin molding formed by the convex part and the convex part in the seal part which is a surface substantially parallel to the mold opening and closing direction formed on the contact surface of the convex part that contacts the resin molded product even if moved Since no gap is generated between the product and the opening of the product, the paint can be prevented from leaking to the non-painted surface side.

JP 2002-292638 A

  However, in the in-mold coating mold and the in-mold coating method described in Patent Document 1, the seal portion formed on the contact surface of the convex portion that contacts the resin constituting the molded product is the opening / closing direction of the mold. In comparison with a general convex part provided with a draft angle, the resin molded product is applied to the mold on the painted surface side where the convex part is provided. The holding force of the resin molded product in the mold opening / closing direction for holding the is increased. As a result, depending on the size, shape, and quantity of the opening, the resin molded product holding power of the mold on the painted surface side where the convex portions are provided increases, and the mold on the painted surface side and the non-painted surface side increase. When the balance of the holding power of the resin molded product in the mold opening / closing direction with the mold is lost, and the mold is opened after molding, the resin molded product that should be held by the mold on the non-coating surface side is originally provided with a projection. There is a problem that a case of being stuck to a mold on the painted surface side that occurs is generated. On the other hand, in order to solve this problem, a reinforcing rib or the like is arranged on the non-painted surface side around the opening of the resin molded product to increase the contact area between the resin molded product and the mold, and the non-painted surface side If the mold holding force of the resin mold is increased, the resin molded product can be held by the mold on the non-painted surface side when the mold is opened. When extruding a resin molded product from the mold with the extrusion pin of the product extrusion means from the mold, there is a problem that the resin molded product holding force of the mold on the non-coating surface side is too strong and the resin molded product is deformed. is there.

  In general, in the in-mold coating method, the resin molded product is held on the mold on the non-painted surface (non-design surface) side, and the painted surface (design surface) of the resin molded product is painted by micro-opening. A gap for injecting paint is formed between the mold on the surface side. Also, the product take-out means, etc. is placed in the mold on the non-painted surface side so that the paint does not enter the sliding part, and resin molding is performed at the sliding part such as an extrusion pin whose tip is placed in the mold cavity The product is removed by directly extruding the non-painted surface of the product in the mold opening and closing direction. Therefore, if the resin molded product is held by the mold on the painted surface side when the mold is opened, a gap for injecting paint is formed between the painted surface side of the resin molded product and the mold on the painted surface side. I can't. Even if a cooling solidification shrinkage in the mold opening / closing direction of the resin molded product or a gap for injecting paint with a movable core is formed, the resin molded product is held in the mold on the painted surface side and the mold is opened. In this case, it is necessary to extrude the resin molded product from the painted surface side, and there is a problem that the paint enters the sliding portion described above. Further, if a sliding portion such as an extrusion pin is disposed on the painted surface, there is a problem that the tip shape of the sliding portion is transferred to the painted surface of the resin molded product, resulting in a defective extrusion mark. Therefore, when the mold is opened regardless of whether the convex part for forming the opening through which the resin molded product passes is formed on the painted surface or the non-painted surface, the resin molded product is on the non-coated surface side. It is desirable to be held in the mold.

  The present invention has been made in view of the above-described problems. Specifically, even in the case of a resin molded product having an opening that penetrates, the opening end on the painted surface (design surface) side is provided. Paint burrs are not generated, and it is possible to prevent the resin molded product from being stuck to the mold on the coated surface side when the mold is opened, and in-mold coating that does not cause deformation of the resin molded product during product extrusion It aims at providing the metal mold | die and the coating method in a metal mold | die.

According to the first aspect of the present invention, as shown in claim 1, molding is performed by injecting molten resin into a mold cavity formed by combining a first mold and a second mold having a paint injection machine. In the resin molded product, a mold for coating in a mold is formed so that a convex portion for forming an opening to penetrate protrudes in the mold opening and closing direction,
The convex portion for forming the opening is on the painted surface side so that the first convex portion formed on the first mold on the non-painted surface side of the resin molded product faces the first convex portion. This is achieved by an in-mold coating mold characterized in that it is formed by abutting against a second convex portion formed in the second mold.

  That is, the convex part for forming the opening part which a resin molded product penetrates forms in the 1st convex part formed in the 1st metal mold | die side by the side of a non-coating surface, and the 2nd metal mold | die side by the side of a coating surface Since it is formed by abutting against the second convex part, it is necessary to open the mold in order to inject the paint, so that the abutting part between the first convex part and the second convex part should be Even if paint enters and paint burrs are formed by re-clamping, the formation location is inside the mold opening and closing direction of the opening, and paint burrs are formed in the design surface at the end of the opening on the paint surface side. It will never be done. Even if the paint enters the abutting portion of the first and second convex portions, the contact surface between the resin molded product and the first convex portion on the non-coating surface side is relatively moved by the micro mold opening. In addition, since the resin molded product adheres to the first convex portion by cooling solidification shrinkage on these contact surfaces, it functions as a seal portion that does not leak any further paint to the non-coating surface side and is injected. It is possible to prevent leakage of paint to the non-painted surface side. Furthermore, since the convex part for forming the opening part which a resin molded product penetrates is formed not only on the second mold on the painted surface side but also on the first mold side on the non-painted surface side, The holding force of the resin molded product in the mold opening / closing direction generated on the contact surface between the part and the resin molded body can be dispersed from the mold on the painted surface side to the mold on the non-painted surface side. As a result, when the mold is opened, it is possible to prevent the resin molded product from being held in the mold on the painted surface side, and reinforcing ribs are arranged on the non-painted surface side around the opening of the resin molded product. Thus, since it is not necessary to increase the resin molded product holding force of the mold on the non-coating surface side, the resin molded product is not deformed when the product is extruded.

  According to a second aspect of the present invention, the first convex portion has substantially no draft angle, the second convex portion is provided with a draft angle, and the tip thereof is the first convex portion. The mold for in-mold coating according to claim 1, wherein the mold is formed in substantially the same cross-sectional shape as the cross-sectional shape orthogonal to the mold opening / closing direction of the tip of the mold.

  When a countersink part for bolts or screws is formed on the painted surface side of the opening, the countersink part is not completely hidden by the head even after the bolts or screws are used. In many cases, the countersink portion on the painted surface side of the opening is required to be painted. In order to inject the paint when the countersink surface of the countersink part has substantially no draft angle, that is, when the countersink surface is substantially parallel to the mold opening / closing direction or has a minute draft angle, Even in a state where the mold is opened, the contact surface between the resin molded product and the second convex portion functions as a seal portion, as in Patent Document 1, and is continuous with the countersink surface or countersink surface of the countersink portion. Since the paint does not enter the surface perpendicular to the mold opening / closing direction, those countersink portions are not painted. If the second convex portion is formed to have a draft angle of a predetermined amount or more, the second convex portion is moved relative to the resin molded product, so that the second convex portion and the second convex portion A gap is formed between the formed opening and the countersink part is painted by entering the countersink surface of the countersink part or a surface perpendicular to the mold opening / closing direction continuous with the countersink surface.

  In addition, if the tip of the second convex portion is formed to have substantially the same cross-sectional shape as the cross-sectional shape orthogonal to the mold opening / closing direction of the tip of the first convex portion having substantially no draft angle, in order to inject the paint Even in a state where the mold is opened, the contact surface between the resin molded product and the tip portion of the second convex portion functions as a seal portion as in Patent Document 1, and the tip of the resin molded product and the second convex portion. Since the paint does not enter the contact surface with the part or the abutted part between the enlarged first convex part and the second convex part, no paint burr is formed at the countersink part on the painting surface side.

Based on this technical idea, as shown in claim 3, after the molding of the resin molded product, the second mold not provided with a paint injection machine is a third metal for forming a coating film provided with a paint injection machine. It is a mold for in-mold coating that is switched to the mold and the in-mold coating is performed,
In order to form a coating film in the opening formed by the second convex portion, a third convex portion having a shape that is longer than the second convex portion by the thickness of the coating film and has a small cross-sectional area perpendicular to the mold opening / closing direction. It is formed in the said 3rd metal mold | die, The metal mold for in-mold coating of any one of Claim 1 to 2 characterized by the above-mentioned.

  As described above, the present invention relates to a mold for in-mold coating in which molding and coating of a resin molded product are performed in the same mold and a method for in-mold coating. The molding and coating can be carried out in an in-mold coating mold and an in-mold coating method performed by separate molds that are switched by a known mold exchanging means arranged in a mold clamping device. That is, a coating material injection machine for forming a coating film having a third convex portion from a second mold that does not have a coating material injection machine by using a mold changing means, and a mold facing the first mold. Even when the paint is injected into the cavity for forming the coating film formed by switching to the third mold having the mold and re-clamping, the contact surface between the resin molded product and the first convex portion on the non-coating surface side is relatively Therefore, the contact surface functions as a seal portion that prevents the paint from leaking further to the non-coating surface side due to cooling solidification shrinkage of the resin molded product.

  Further, in order to form a coating film in the opening formed by the second convex portion, the third convex having a shape that is longer than the second convex portion by the thickness of the coating film and has a small cross-sectional area perpendicular to the mold opening / closing direction. Since the part is formed in the third mold, the coating film forming cavity can be formed between the opening formed by the second convex part and the third convex part. When the paint enters the coating film forming cavity, the opening formed by the second convex portion is painted. Therefore, even if the opening part formed by the 2nd convex part is an opening part which does not have a draft angle substantially, painting is possible. Furthermore, since the gap between the abutting portions of the first convex portion and the third convex portion is formed very small, it is possible to prevent the paint from entering the abutting portion of the first convex portion and the third convex portion. it can. Even if the paint enters the abutting part of the first and third convex parts, the amount of the paint is very small, so the paint burr to be formed is small, and the formation part does not need to be painted. The opening can be inside the mold opening / closing direction, and no paint burr is formed at the end of the opening on the paint surface side.

  Further, the third convex part is longer than the second convex part by the thickness of the coating film and has a small cross-sectional area perpendicular to the mold opening / closing direction, and the difference in the area of the contact surface with each resin molded product is very small. It is slight. Therefore, the resin molded product holding force in the mold opening / closing direction generated on the contact surface between the third convex portion and the resin molded product, and the resin molded product holding force in the mold opening / closing direction generated on the contact surface between the second convex portion and the resin molded product. The difference is negligible. When the mold is opened, it is possible to prevent the resin molded product from being held by the mold on the painted surface side, and the reinforcement is applied to the non-painted surface side around the opening of the resin molded product. Since it is not necessary to increase the resin molded product holding force of the mold on the non-coating surface side by arranging ribs or the like, the resin molded product is not deformed during product extrusion.

In addition, as shown in claim 4, an in-mold coating method using the in-mold coating mold according to any one of claims 1 to 2,
A molding step of molding the resin molded product by injecting and filling molten resin into the mold cavity formed by combining the first mold and the second mold;
The first mold and the second mold are micro-opened in a state where the molded resin molded product is held by the first mold on the non-coating surface side, and the painted surface of the resin molded product A paint injection step of injecting paint from the paint injection machine into a gap formed between the side and the inner surface of the mold cavity of the second mold;
The first mold and the second mold that have been micro-opened are re-clamped, and the paint injected into the gap is closely integrated with the painted surface of the resin molded product to form a coating film A coating film forming process,
The in-mold coating method is preferably characterized by comprising:

Furthermore, as shown in claim 5, there is provided an in-mold coating method using the in-mold coating mold according to claim 3,
A molding step of molding the resin molded product by injecting and filling molten resin into the mold cavity formed by combining the first mold and the second mold not provided with the paint injector;
In a state where the molded resin molded product is held in the first mold on the non-coating surface side, the first mold and the second mold not equipped with a paint injection machine are opened, and a mold is opened. A mold exchanging step in which a mold facing the first mold by the mold exchanging means is switched from the second mold not equipped with a paint injector to the third mold for forming a coating film;
Cavity for forming a coating film formed between the painted surface side of the resin molded product and the inner surface of the mold cavity of the third mold by clamping the first mold and the third mold. A paint film forming step of forming the paint film by injecting the paint from the paint injector and injecting the paint injected into the paint film forming cavity into close contact with the paint surface of the resin molded product; ,
An in-mold coating method characterized by comprising:

The in-mold coating mold according to the present invention is formed by injecting and filling molten resin into a mold cavity formed by combining a first mold and a second mold having a paint injection machine. A mold for coating in a mold formed so that a convex part for forming an opening to penetrate in a resin molded product protrudes in a mold opening and closing direction,
The convex portion for forming the opening is on the painted surface side so that the first convex portion formed on the first mold on the non-painted surface side of the resin molded product faces the first convex portion. Even if a paint burr is formed, the formation location is the inside of the opening and closing direction of the opening, and the coating surface side is formed. A paint burr is not formed in the design surface of the end of the opening.

  In addition, even if the paint enters the abutting portion of the first convex portion and the second convex portion, the contact surface between the resin molded product and the first convex portion on the non-coating surface side functions as a seal portion and is injected. It is possible to prevent the paint from leaking to the non-painted surface side. Furthermore, since the convex part for forming the opening part which a resin molded product penetrates is formed not only on the second mold on the painted surface side but also on the first mold side on the non-painted surface side, The holding force of the resin molded product in the mold opening / closing direction generated on the contact surface between the part and the resin molded body can be dispersed from the mold on the painted surface side to the mold on the non-painted surface side. As a result, when the mold is opened, it is possible to prevent the resin molded product from being held in the mold on the painted surface side, and reinforcing ribs are arranged on the non-painted surface side around the opening of the resin molded product. Thus, since it is not necessary to increase the resin molded product holding force of the mold on the non-coating surface side, the resin molded product is not deformed when the product is extruded.

In addition, the mold for in-mold coating according to the present invention is the third mold for forming a coating film in which the second mold not provided with the paint injection machine is provided with the paint injection machine after the molding of the resin molded product. It is a mold for in-mold coating that is switched to the mold and painted in the mold,
In order to form a coating film in the opening formed by the second convex portion, a third convex portion having a shape that is longer than the second convex portion by the thickness of the coating film and has a small cross-sectional area perpendicular to the mold opening / closing direction. However, since it is formed in the third mold, the opening formed by the second protrusion can be painted even if it is an opening having substantially no draft angle, and the first protrusion In addition, it is possible to prevent the paint from entering the abutting portion of the third convex portion, and no paint burr is formed at the end of the opening on the painted surface side.

  Furthermore, since the difference in the area of the contact surface between the third convex portion and the second convex portion and the respective resin molded product is negligible, the resin in the mold opening / closing direction generated on the contact surface between the third convex portion and the resin molded product. The difference between the holding force of the molded product and the holding force of the resin molded product in the mold opening and closing direction that occurs on the contact surface between the second convex part and the resin molded product is very small. The resin molded product can be prevented from being held, and a reinforcing rib etc. is arranged on the non-painted surface side around the opening of the resin molded product to hold the resin molded product on the non-painted surface side. Therefore, when the product is extruded, the resin molded product is not deformed.

It is a schematic sectional drawing of the metal mold | die for in-mold coating which shows the formation process which concerns on Example 1 of this invention. It is an expanded sectional view of the opening part of the resin molded product which concerns on Example 1 of this invention. It is a schematic sectional drawing of the metal mold | die for in-mold coating which shows the shaping | molding process which concerns on Example 2 of this invention. It is a schematic sectional drawing of the metal mold | die for in-mold coating which shows the shaping | molding process which concerns on Example 3 of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view of an in-mold coating mold showing a molding process according to Embodiment 1 of the present invention. 1A is a molding process, FIG. 1B is a paint injection process, FIG. 1C is an enlarged view of an opening in the paint injection process, and FIG. 1D is an enlarged view of an opening in a paint film forming process. FIG. 1E is an enlarged view of the opening in the mold opening process, and FIG. 1F is also an enlarged view of the opening in the mold opening process. FIG. 2 is an enlarged cross-sectional view of the opening of the resin molded product according to Example 1 of the present invention.

As shown in FIG. 1 (a), in the in-mold coating mold 1, a first mold 10 attached to a mold clamping device (not shown) and a second mold attached to a mold clamping device (not shown). A molding process is performed in which a mold resin 12 is molded by injecting and filling molten resin from an injection unit (not shown) into a mold cavity 12 a formed in combination with the mold 11. The first mold 10 has a mold cavity on the non-painted surface (non-design surface) side of the mold cavity 12a, and an opening through which the resin molded product 12 passes is formed on the mold cavity surface. the first convex portion T ₁₀ to be a part of the convex portion of the are formed. The second mold 11 has a mold cavity of the coated surface (design surface) side of the mold cavity 12a, Its mold cavity surface, so as to face the first projecting portion T _10, the resin molded product is formed a second projecting portion T ₁₁ to be a part of the convex portion for forming an opening through the 12, the abutment between the first convex portion T ₁₀ and the second convex portion T _11, the resin molded product The entire 12 through openings are formed. A first convex portion T ₁₀ protrusions between the gap 12b of the abutting portion between the second convex portion T ₁₁ is either each of the protrusions is formed so as to contact, or for the protection of the abutting portion Even when a slight gap is formed, the gap is preferably as small as possible. Since the interprotrusion gap 12b is a very small gap, the molten resin does not enter the interprotrusion gap 12b. The second mold 11 is provided with a paint injection machine 13c for injecting a paint for forming a coating film on the coating surface of the resin molded product 12.

  In general, even for resin molded products having openings that pass through, such as screw holes and insertion holes for inserting other parts, the wall thickness itself is thin for weight reduction, and only the openings are non- When a rising to the painted surface side or a boss on the non-painted surface side is used to reinforce the opening, secure the distance in the mold opening and closing direction, and form the necessary cross-sectional shape in the mold opening and closing direction There are many. Also in Example 1, in order to form a necessary cross-sectional shape in the mold opening / closing direction, an opening having a boss portion provided on the non-coating surface side is targeted. Further, it is assumed that the mold dividing surface of the first mold 10 and the second mold 11 adopts a shear edge structure for preventing the paint from leaking out from the mold cavity 12a. The shear edge structure is sometimes called a squeaky structure or an inlay structure, and the paint is applied as a structure of a fitting part that forms a mold dividing surface or in a mold for in-mold coating. This structure is generally known as a structure for preventing leakage from the mold dividing surface. This adoption is intended to simplify the explanation, and excludes the fact that the mold dividing surface is not a common flat structure but a shear edge structure using a known paint leakage prevention mechanism. is not.

  After the resin molded product 12 is cooled and solidified, as shown in FIG. 1B, the second mold 11 is micro-opened in a direction away from the first mold 10 by a distance d, and the painted surface of the resin molded product 12 is applied. A paint injection step is performed in which a paint injection gap 13a is formed between the mold cavity surface of the second mold 11 and the paint injection gap 13a is injected from the paint injection machine 13c into the paint injection gap 13a. The distance in the mold opening / closing direction of the coating material injection gap 13a is obtained by adding the amount of cooling solidification shrinkage in the mold opening / closing direction of the resin molded product 12 to the minute mold opening amount d. Further, when the coating material injection gap 13a is formed, the inter-convex gap 12b is also enlarged by a distance d in the mold opening / closing direction. A predetermined amount of coating material 13b is injected from the coating material injection machine 13c through the coating material injection gate into the coating material injection gap 13a. As the paint 13b, a thermosetting paint having excellent adhesion to the base resin of the resin molded product 12 is generally employed.

Hereinafter, the remaining steps will be described with reference to FIG. 1C to FIG. As shown in FIG. 1 (c), the first convex portion T ₁₀ and the second convex portion T _11, substantially parallel to both the mold opening and closing direction, a convex portion having substantially the same cross-sectional shape in the mold opening and closing direction. Both convex portions or one convex portion may be provided with a minute draft angle of greater than 0 and 1.0 degrees or less in the mold opening and closing direction, and in any case, the convex section has substantially no draft angle. Due to the minute mold opening of the second mold 11, the contact surface t ₁ between the resin molded product 12 and the first convex portion T ₁₀ does not move relatively and does not slide, and the contact surface t ₁ molded article 12 is in close contact with the cooled and solidified shrinkage to the first convex portion T _10, not leak the more paint 13b to the non-coated surface side to function as a seal portion, the injected coating 13b to the non-coated side Leakage can be prevented.

On the other hand, when fine small opening of the second mold 11, the second convex portion T ₁₁ with respect to the resin molded product 12 is relatively moved. However, since these contact surfaces t ′ ₂ (t ₂ ) have substantially no draft angle in the mold opening and closing direction, as described in paragraph 0014 of Patent Document 1, these contact surfaces t ′ ₂ If the length in the mold opening / closing direction is a predetermined amount or more, it functions as a seal portion that does not leak the coating material 13b injected into the coating material injection gap 13a to the non-coating surface side. Although it depends on the resin molded product, from the applicant's experience, it usually functions as a seal if it is about 1 mm. Since the contact surface t ′ ₂ functions as a seal portion, the paint 13 b does not enter the contact surface t ′ ₂ (t ₂ ) nor the enlarged inter-convex gap 12 b, and the end of the opening on the paint surface side No paint burr is formed on the surface.

After completion of the paint injection process, as shown in FIG. 1D, the second mold 11 is re-clamped to the first mold 10 side, and the paint injection gap 13a is formed on the painted surface of the resin molded product 12. A paint film forming step is performed in which the injected paint 13b is uniformly expanded and closely integrated to form the paint film 13. Even when the second convex portion T ₁₁ is moved relative to the resin molded product 12 by re-clamping, the contact surface t ′ ₂ of the second convex portion T _{11 with} the resin molded product 12 is the contact surface. Since it functions as a seal portion until t ₂ , the coating film 13 is formed up to the opening end portion of the coating surface, and no paint burr is formed in the design surface of the opening end portion on the coating surface side.

Further, the first convex portion T ₁₀ formed in the first mold 10 of the non-coated surface side, and the second convex portion T ₁₁ formed in the second mold 11 of the coated surface side, each of the resin molding The resin molded product holding force F in the mold opening and closing direction generated on the contact surface with the product 12 is that of the contact surface between each convex portion and the resin molded product 12 unless there is an extreme draft angle or inclined surface on each convex portion. It is proportional to area A. In Example 1, since both are convex portions having substantially the same cross-sectional shape in the mold opening / closing direction with substantially no draft angle in the mold opening / closing direction, the area of the contact surface between each convex portion and the resin molded product 12 A is approximately proportional to the protruding length of each convex portion in the mold opening / closing direction. Here, T ₁ the projecting length of the mold opening and closing direction of the first convex portion T _10, when the mold opening and closing direction protruding length of the second convex portion T ₁₁ and T _2, the convex portion is first protrusion T ₁₀ If by being divided into a second convex portion T _11, of the mold opening and closing direction of the resin molded article holding force F generated on the contact surface with the entire convex portion and the resin molded body, the resin molded with the first convex portion T ₁₀ From the second mold 11 on the painted surface side to the first mold 10 on the non-painted surface side by F ₁ = F × T ₁ / (T ₁ + T ₂ ) generated on the contact surface t ₁ with the product 12. Can be dispersed. As a result, it is possible to prevent the resin molded product 12 from being stuck to the second mold 11 on the painted surface side when the mold is opened.

After the coating 13b is cured, a mold opening process is performed in which the second mold 11 is opened in the direction of separating from the first mold 10 as shown in FIG. As described above, when the mold is opened, the second mold 11 is opened without holding the resin molded product 12, and the resin molded product 12 is the first mold _{10 in} which the first convex portion T ₁₀ is formed. Retained. After the mold is opened, the resin molded product 12 held by the first mold 10 is pushed out of the mold cavity of the first mold 10 by a product pushing means (not shown) arranged on the first mold 10 side. Here, it is not necessary to dispose reinforcing ribs or the like on the non-painted surface side around the opening of the resin molded product 12 to increase the resin molded product holding force F1 of the _first mold on the non-painted surface side. Therefore, as described above, the resin molded product 12 is not deformed when the product is extruded. After the extrusion of the resin molded product 12 is completed, the resin molded product 12 is conveyed out of the mold by a product take-out means (not shown). Thus, by repeating the steps from FIG. 1 (a) to FIG. 1 (e), the coating film 13 is formed up to the opening end of the coating surface, as shown in FIG. The formed resin molded product 12 is continuously molded.

  Although omitted in the above description for the sake of simplicity, the resin molded product 12 is held by the second mold 11 by this effect even when the second mold 11 is opened in the paint injection process. Needless to say, the mold will be opened.

Earlier, in the coating injection step and the coating film forming step shown in FIG. 1 (d) in FIG. 1 (c), the contact surface t _'2 of the resin molded article 12 and the second convex portion _{T 11 (t 2)} is sealed portion However, the length of the contact surface t ′ ₂ (t ₂ ) in the mold opening / closing direction is smaller than a predetermined amount, and the paint 13b should contact the contact surface t ′ ₂ (t ₂ ), even if it penetrated into the enlarged projecting portion between the gap 12b, a contact surface t ₁ of the first convex portion T ₁₀ described above functions as a seal portion, tight any more paint 13b to the non-coated surface side. That is, as shown in FIG. 1 (f), the coating 13 b that has entered the enlarged inter-convex gap 12 b through the contact surface t ′ ₂ (t ₂ ) is applied to the coating film forming step of FIG. By re-clamping, the gap 12b between the convex portions is reduced to the original distance, so that it is compressed to substantially the same thickness, and is formed as a paint burr 13 ″ inside the mold opening / closing direction of the opening, and the opening end on the painting surface side In addition, no paint burr is formed on the portion, and the contact surface t ′ ₂ (t ₂ ) between the resin molded product 12 and the second convex portion T ₁₁ has substantially no draft angle in the mold opening / closing direction. hardly adhered coating 13b by the sliding of the second protrusion T _11, the second die opening and closing direction of the inner surface of the opening formed by the convex portion T ₁₁ is not painted. formed paint burr 13 "is thin It is very fragile and can be easily removed by inserting screws or other parts into the opening. Therefore, there is almost no need to provide a separate step for removing the paint burr 13 ″ after the molding of the resin molded product 12. Even if it is necessary, the removal is very easy unlike the resin burr. .

  A second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view of an in-mold coating mold showing a molding process according to Embodiment 2 of the present invention. FIG. 3A is an enlarged view of the opening in the paint injection process, FIG. 3B is an enlarged view of the opening in the coating film forming process, and FIG. 3C is an enlarged view of the opening in the mold opening process.

  The difference between Example 2 and Example 1 is that it is not an opening having substantially no draft angle in the mold opening and closing direction, but a countersink surface provided with a draft angle on the painted surface (design surface) side, It has a countersink part composed of a surface that is continuous with the countersink surface and orthogonal to the mold opening and closing direction, and is on the non-painted surface (non-design surface) side from the surface that is orthogonal to the mold opening and closing direction that is continuous On the other hand, an opening having a straight body portion substantially free from a draft angle in the mold opening and closing direction is formed. Other configurations of the in-mold coating mold and the in-mold coating method are basically the same as those in the first embodiment, and only the differences from the first embodiment will be described. For the same reason, in FIG. 3, a drawing corresponding to the schematic cross-sectional view of the in-mold coating mold showing the molding process of FIG. 1A and the paint injection process of FIG. 1B is omitted.

As shown in FIG. 3 (a), first protrusion T ₂₀ is substantially parallel to the mold opening and closing direction, a convex portion having substantially the same cross-sectional shape in the mold opening and closing direction. A minute draft angle of greater than 0 and 1.0 degree or less may be provided in the mold opening / closing direction, and in any case, the convex portion has substantially no draft angle as in the first embodiment. Due to the minute mold opening of the second mold 21, the contact surface t ₁ between the resin molded product 22 and the first convex portion T ₂₀ does not move relatively and does not slide. As described above, it functions as a seal portion that prevents the paint 13b from leaking further to the non-painted surface side. Second convex portion T ₂₁ has a flat surface to form an inclined surface forming a predetermined amount or more vent angle counterbore surfaces provided, a plane perpendicular to the mold opening and closing direction continuous to the counter sunk surface its tip facing the first convex portion T ₂₀ of the plane, substantially the same cross-sectional shape, substantially vent angle the mold opening and closing direction and the cross-sectional shape perpendicular to the die opening and closing direction of the distal end of the first convex portion T ₂₀ It is formed to have a straight body T ₂₂ is not. Therefore, the fine small opening of the second mold 21, the gap continuous with the coating material injection gap 13a between the second convex portion T ₂₁ the opening formed by the second convex portion T ₂₁ is formed, the paint 13b is injected.

The fine small opening, the first convex portion _{T 20} is also convex portion between the gap 22b is enlarged with a straight body portion _{T 22} of the second convex portion _{T 21,} the straight body portion _{T 22} of the second convex portion _{T 21} is since there is no substantial bleeding angle in a mold opening and closing direction, the contact surface between the resin molding 22 and the straight body portion T ₂₂ of the second convex portion T ₂₁ functions as a seal portion, the coating 13b has a resin molded article 22 Neither the contact surface of the second convex portion T _{21 with} the straight body portion T ₂₂ nor the enlarged inter-convex gap 22 b enters, and no paint burr is formed on the countersink portion on the painted surface side. . Even if the paint 13b enters the inter-convex gap 22b, the place where the paint burr is formed can be inside the opening and closing direction of the opening, which does not need to be painted. No paint burr is formed on the part. Further, the resin molded article 22 the contact surface between the cylindrical body portion T ₂₂ of the second convex portion T _21, because there is no substantial bleeding angle in a mold opening and closing direction, the straight body portion T ₂₂ of the second convex portion T ₂₁ sliding coating 13b is hardly deposited by a, the mold opening and closing direction of the inner surface of the opening formed by the straight body portion T ₂₂ of the second convex portion T ₂₁ is not painted is as previously described.

Here, the punching angle of the second convex portions provided on the inclined surface forming the countersink surfaces of the T ₂₁ "predetermined amount or more", the fine small opening, the opening formed by the second convex portion T ₂₁ Is an angle at which a sufficient gap is formed to allow the paint 13b to enter. The vent angle, depending on the length of the mold opening and closing direction of the contact surface between the resin molding 22 and the second convex portion T _21, mold opening and closing direction 5 degrees or more, preferably 10 degrees or more.

  After completing the paint injection process, as shown in FIG. 3B, the second mold 21 is re-clamped to the first mold 20 side, and the paint 13b is uniformly expanded on the painted surface of the resin molded product 22. Then, a paint film forming step is performed in which the paint film 13 is formed by close integration.

  After the coating 13b is cured, a mold opening process for opening the second mold 21 in the direction of separating the first mold 20 from the first mold 20 is performed as shown in FIG. The coating material 13b is also injected into the coating material injection space 13a and the space that continues to the coating material injection space 13a, and is compressed by re-clamping in the subsequent coating film forming process. The coating film 13 ′ can also be formed on a countersink part constituted by a countersink surface and a surface orthogonal to the mold opening / closing direction that is continuous with the countersink surface.

  Embodiment 3 of the present invention will be described with reference to FIG. FIG. 4 is a schematic cross-sectional view of a mold for in-mold coating showing a molding process according to Example 3 of the present invention. 4A is the molding process, FIG. 4B is the first half of the mold exchanging process, FIG. 4C is the second half of the mold exchanging process, FIG. 4D is the coating film forming process, and FIG. The mold opening process is shown.

  The difference between Example 1 and Example 2 in Example 3 is that the molding and coating of the resin molded product are not performed in the same mold, but a known mold exchange arranged in the mold clamping device. The point performed by separate molds that are switched by means, and the countersink portion on the paint surface (design surface) side are substantially free of a draft angle, and in the mold opening / closing direction continuous to the countersink surface It has a countersink part composed of orthogonal surfaces, and is substantially in the mold opening / closing direction from the surface orthogonal to the mold opening / closing direction continuous to the countersink surface toward the non-coating surface (non-design surface) side. There are two points, that is, an opening having a straight body having no draft angle is formed.

As shown in FIG. 4 (a), a molded resin 32 is molded by injection-filling molten resin into a mold cavity 32a formed by combining a first mold 30 and a second mold 33. A process is performed. The first convex portion T ₃₀ formed in the first mold 30 is substantially parallel to the mold opening and closing direction, a convex portion having substantially the same cross-sectional shape in the mold opening and closing direction. In the mold opening / closing direction, a fine draft angle of greater than 0 and 1.0 degree or less may be provided, and in any case, the convex portion has substantially no draft angle. Due to the minute mold opening of the second mold 21, the contact surface t ₁ between the resin molded product 32 and the first convex portion T ₃₀ does not move relatively and does not slide. As described above, it functions as a seal portion that prevents the paint 13b from leaking further to the non-painted surface side.

Second convex portion T ₃₃ has a flat surface to form a surface forming a free countersink surfaces of substantially punching angle, a plane perpendicular to the mold opening and closing direction continuous to the counterbored surface, of the plane a tip facing the first convex portion T ₃₀ is substantially the same cross-sectional shape, substantially straight body has no vent angle the mold opening and closing direction and the cross-sectional shape perpendicular to the die opening and closing direction of the distal end of the first convex portion T ₃₀ and it is formed to have a section T _34. The cross-sectional area perpendicular to the mold opening / closing direction of the surface of the second convex portion T ₃₃ forming the countersink surface having substantially no draft angle is larger than the cross-sectional area perpendicular to the mold opening / closing direction of the first convex portion T _30. . Further, the convex portion between the gap 32b of the abutting portion between the straight body portion T ₃₄ of the first convex portion T ₃₀ and the second convex portion T ₃₃ is either each of the protrusions is formed to be in contact, or, Even when a slight gap is formed to protect the butted portion, it is preferable that the gap be as small as possible.

  After the molding process is completed and the resin molded product 32 is cooled and solidified, the first mold 30 and the second mold 33 are molded with the resin molded product 32 held by the first mold 30 on the non-painted surface side. A mold exchanging step is performed in which the mold opposed to the first mold 30 is switched from the second mold 33 to the third mold 35 for forming a coating film by a mold exchanging means (not shown). FIG. 4B shows a state where the first mold 30 and the second mold 33 in the first half of the mold exchanging process are opened. As described above, when the mold is opened, the resin molded product 32 is held by the first mold 30 on the non-coating surface side without being held by the second mold 33.

After the first mold 30 and the second mold 33 are opened, a mold facing the first mold 30 is transferred from the second mold 33 to form a coating film by a mold exchanging means (not shown). It is switched to 3 molds 35. FIG. 4C shows a state where the mold changing process in the latter half of the mold changing process is completed. Subsequently, in the coating film forming step shown in FIG. 4D, first, the first mold 30 and the third mold 35 are clamped and the resin molded product 32 held in the first mold 30 is retained. A paint film forming cavity 33 a for forming a paint film is formed between the paint surface and the inner surface of the mold cavity of the third mold 35. The third convex portion T ₃₅ and the straight barrel portion T ₃₆ of the third mold 35 are inserted into the opening formed by the second convex portion T ₃₃ and the straight barrel portion T ₃₄ of the second mold 33. The third convex portion T ₃₅ and the straight body portion T ₃₆ are formed to have a shape that is longer than the second convex portion T ₃₃ and the straight body portion T ₃₄ by the thickness of the coating film and has a small cross-sectional area perpendicular to the mold opening / closing direction. and for that, also between the second convex portion T ₃₃ and the straight body portion T ₃₄ opening and the third convex portion T ₃₅ and cylindrical body portion T ₃₆ formed by, continuous in the coating film-forming cavity 33a paint A film forming cavity is formed. Therefore, the opening formed by the second convex portion T ₃₃ is even substantially punching angle no opening is painted. Further, since the inter-convex gap 32b ′ at the abutting portion between the first convex part and the third convex part is very small, it is possible to prevent the coating material from entering the inter-convex gap 32b ′. Even if the paint enters the gap 32b 'between the convex parts, the amount of the paint is very small, so the paint burr to be formed is small, and the formation part does not need to be painted. The paint burr is not formed in the countersink portion on the painted surface side.

Then, from the paint injector 13c disposed on the third mold 35, paint injection gap 33a is formed by the third mold 35, and is formed by the second convex portion _{T 33} and the straight body portion _{T 34} and between the opening and the third convex portion T ₃₅ and cylindrical body portion T _36, paint 13b via a paint injection gate formed coating film-forming cavity so as to be continuous to the paint film-forming cavity 33a is Tokoro A fixed amount is injected. After the coating material 13b is injected, the coating film forming process is maintained until the coating material 13b is uniformly expanded on the coating surface of the resin molded product 32 and is tightly integrated by curing.

After the coating 13b is cured, a mold opening process is performed in which the third mold 35 is opened in the direction of separating from the first mold 30 as shown in FIG. 4 (e). As described previously, the injected coating 13b includes a coating film-forming cavity 33a as well, the opening formed by the second convex portion T ₃₃ and cylindrical body portion T ₃₄ continuous with the coating film-forming cavity 33a Since it is also injected into the coating film forming cavity formed between the third convex portion T ₃₅ and the straight body portion T ₃₆ , not only the coating film 13 on the coating surface, plane perpendicular to the mold opening and closing direction continuous to the counter sunk surface and a second die opening and closing direction parallel to painting also the plane layer 13 of the opening formed by the straight body portion T ₃₄ protrusions T ₃₃ ' Can be formed.

Here, the area A ₃ of the contact surface t ₃ between the resin molding 32 and the third convex portion T ₃₅ and the straight body portion T ₃₆ formed on the third mold 35, and the second mold 33 are formed. the area _{a 2} of the contact surface _{t 2} of the second convex portion _{T 33} and cylindrical body portion _{T 34,} minutes the cavity for the coating film is formed, toward the area _{a 3} is smaller than the area _{a 2.} However, since the difference is negligible, A ₃ ≈A ₂ <A ₁ . As a result, the resin molded product holding force in the mold opening / closing direction generated on the contact surface t ₃ of the third convex portion T ₃₅ and the straight body portion T ₃₆ and the resin molded product 32, and the contact surface t of the second convex portion and the resin molded product ₂ , the difference between the holding force of the resin molded product in the mold opening and closing direction is very small. Therefore, when the mold is opened, the resin molded product 32 is opened without being held by the third mold 35, The resin molded product can be prevented from being held on the mold, and reinforcing ribs and the like are arranged on the non-painted surface side around the opening of the resin molded product 32, so that the first metal on the non-painted surface side is arranged. Since it is not necessary to increase the resin molded product holding force of the mold 30, the resin molded product 32 is not deformed during product extrusion.

As described above, the mold and the coating method of the present invention are the same as those in the first embodiment and the in-mold coating mold and the in-mold coating method in which the molding and coating of the resin molded product are performed in separate molds. The same effect as in Example 2 and another effect that the countersink portion is painted even when the countersink surface on the painted surface side has substantially no draft angle in the mold opening / closing direction. Further, although not shown, in Example 3, the surfaces forming the countersink surfaces of the second convex portion T ₃₃ is, even when the predetermined amount or more of vent angle in the same manner as in Example 2 is provided, The third convex portion T ₃₅ and the straight barrel portion T ₃₆ are formed so as to correspond to the shapes of the second convex portion T ₃₃ and the straight barrel portion T ₃₄ , whereby the countersink portion on the painting surface side is painted. Needless to say.

  The present invention is not limited to the above embodiment and can be implemented in various forms. For example, in Example 1 to Example 3, in order to form a necessary cross-sectional shape in the mold opening / closing direction, the opening part provided with the boss part on the non-coating surface side is targeted, but the requirement of the present invention can be satisfied. For example, it can also be used for an opening through which a flat resin molded product having a large thickness in the mold opening and closing direction passes. Further, in the second embodiment, it has been described that the countersunk portion is painted. However, the countersink surface of the countersink portion is formed so that there is substantially no draft angle in the mold opening and closing direction, It can also be made to function as a seal part and the countersink part is not painted.

DESCRIPTION OF SYMBOLS 1 Metal mold | die for coating 10 1st metal mold | die 11 2nd metal mold | die 12 Resin molded product 12a Mold cavity 12b Gap | interval 13 between convex parts Coating film 13a Gap | paint gap 13b Paint 13c Paint injection machine 13 'Opening part Paint film 13 ”on coating surface side Paint burrs T ₁ First protrusion protruding length
t ₁ contact surface (between resin molded product and first projection)
T2 _2nd convex protrusion length
t ₂ contact surface (with resin molded product and 2nd convex part)
t ' ₂ contact surface (between the resin molded product and the second protrusion when the micro mold is opened)
T ₁₀ first convex portion _{T 11} second projecting portion 20 first mold 21 and the second die 22 resin molded article 22a between mold cavity 22b protrusions gap _{T 20} first protrusion _{T 21} second projecting portion _{T 22} straight Body 30 First mold 32 Resin molded product 32a Mold cavity 32b Inter-convex gap 32b 'Inter-convex gap 33 Second mold 33a Paint film forming cavity 35 Third mold T ₃₀ First convex T ₃₃ 2 protrusions _{T 34} cylindrical body portion _{T 35} third convex portion _{T 36} cylindrical body portion _{t 3} the contact surface (the resin molded product and a third convex portion)

Claims (5)

In order to form a penetrating opening in a resin molded product formed by injecting and filling molten resin into a mold cavity formed by combining a first mold and a second mold equipped with a paint injection machine The mold for coating in the mold is formed so that the convex part of the mold protrudes in the mold opening and closing direction,
The convex portion for forming the opening is on the painted surface side so that the first convex portion formed on the first mold on the non-painted surface side of the resin molded product faces the first convex portion. A mold for in-mold coating, which is formed by abutting against a second convex part formed on the second mold.   The first convex part has substantially no draft angle, the second convex part is provided with a draft angle, and the tip of the first convex part is a cross section perpendicular to the mold opening / closing direction of the tip of the first convex part. The mold for in-mold coating according to claim 1, wherein the mold is formed in substantially the same cross-sectional shape as the shape. After molding the resin molded product, the second mold not equipped with a paint injection machine is switched to a third mold for forming a coating film provided with a paint injection machine to perform in-mold coating. A mold for painting,
In order to form a coating film in the opening formed by the second convex portion, a third convex portion having a shape that is longer than the second convex portion by the thickness of the coating film and has a small cross-sectional area perpendicular to the mold opening / closing direction. Is formed in the third mold, The in-mold coating mold according to claim 1, wherein the third mold is formed. An in-mold coating method using the in-mold coating mold according to any one of claims 1 to 2,
A molding step of molding the resin molded product by injecting and filling molten resin into the mold cavity formed by combining the first mold and the second mold;
The first mold and the second mold are micro-opened in a state where the molded resin molded product is held by the first mold on the non-coating surface side, and the painted surface of the resin molded product A paint injection step of injecting paint from the paint injection machine into a gap formed between the side and the inner surface of the mold cavity of the second mold;
The first mold and the second mold that have been micro-opened are re-clamped, and the paint injected into the gap is closely integrated with the painted surface of the resin molded product to form a coating film A coating film forming process,
An in-mold coating method characterized by comprising: An in-mold coating method using the in-mold coating mold according to claim 3,
A molding step of molding the resin molded product by injecting and filling molten resin into the mold cavity formed by combining the first mold and the second mold not provided with the paint injector;
In a state where the molded resin molded product is held in the first mold on the non-coating surface side, the first mold and the second mold not equipped with a paint injection machine are opened, and a mold is opened. A mold exchanging step in which a mold facing the first mold by the mold exchanging means is switched from the second mold not equipped with a paint injector to the third mold for forming a coating film;
Cavity for forming a coating film formed between the painted surface side of the resin molded product and the inner surface of the mold cavity of the third mold by clamping the first mold and the third mold. A paint film forming step of forming the paint film by injecting the paint from the paint injector and injecting the paint injected into the paint film forming cavity into close contact with the paint surface of the resin molded product; ,
An in-mold coating method characterized by comprising:

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