JP2002240090A - In-mold coating molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-mold coating molding method capable of easily forming a coating layer having high design effect on the surface of a resin molded product, by suppressing the elastic deformation of a bent piece when a coating agent is injected in the gap between the surface of the resin molded product and the cavity of a mold. SOLUTION: A mold 21 for in-mold coating molding is equipped with a fixed mold 22 and a movable mold 23 and constituted so as to enable mold clamping and mold opening in an up and down direction to manufacture a long product wherein the coating layer is provided on the surface of a base material 12 (resin molded product) having an inverted U-shaped cross section. A deformation preventing ridge 24 for forming a recessed groove 18 extending in the longitudinal direction of the fixed mold 22 along the leading edge of the bent piece 16 of the base material is provided to the fixed mold 22 to prevent the elastic deformation of the bent piece 16 when mold clamping pressure is lowered. In the in-mold coating molding method, the base material 21 is injection-molded in the mold 21 for in-mold coating molding and the movable mold 23 is subsequently opened by predetermined quantity and the coating agent is injected in the gap 30 between the base material 12 and the movable mold 23 to be cooled and cured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of molding a resin molded article in a mold into a predetermined shape, and then injecting and curing a coating agent between the surface of the resin molded article and the cavity of the mold. And forming a coating layer on the surface of a resin molded product in the same mold.

[0002]

2. Description of the Related Art Conventionally, as an in-mold coating forming method of this kind, an in-mold coating method disclosed in Japanese Patent Application Laid-Open No. 11-277577 is known. In the in-mold coating method, after molding a synthetic resin molding material by applying a mold clamping pressure in a molding die including a fixed mold portion and a movable mold portion, the molding die inner surface is obtained in the same molding die. The surface of the molded article is coated with the coating agent while injecting a coating agent between the molded article and the surface of the molded article. Further, the mold clamping again after the injection of the coating agent is carried out under the conditions of a predetermined multi-stage variable mold clamping pressure and a mold clamping pressure transition time. The molded article manufactured by using the in-mold coating method has a multi-stage mold clamping pressure after coating agent injection, and controls the transition time of the mold clamping pressure, so that the ribs and the boss portion of the molded article are controlled. It is configured such that the swelling phenomenon (hump) of the (pressed portion) is prevented and high quality can be ensured.

[0003]

However, in the above-mentioned conventional in-mold coating method, the most suitable multi-stage variable type mold clamping is considered in consideration of the type of the synthetic resin molding material used, the shape of the molded product, and the like. Since it was necessary to determine the conditions of the pressure and the transition time of the mold clamping pressure, the test was performed based on very complicated test and research results.

[0004] The present invention has been made by focusing on the problems existing in the prior art as described above. The purpose is to suppress the elastic deformation of the bent pieces when injecting the coating agent between the surface of the resin molded product and the cavity of the mold, and to provide a highly designable coating layer on the surface of the resin molded product. Is to provide an in-mold coating molding method configured to easily form a coating.

[0005]

In order to achieve the above object, an in-mold coating forming method according to the first aspect of the present invention provides an in-mold coating forming method in a mold having a fixed mold portion and a movable mold portion. After molding the resin molded article, reduce the mold clamping pressure of the mold or separate the fixed mold section and the movable mold section, and between the surface of the resin molded article and the cavity of the movable mold section. By injecting and curing a coating agent, an in-mold coating molding method for producing an in-mold coating molding in which a coating layer is formed on the surface of the resin molding in the same mold, wherein a bent piece is formed on the resin molding. And a deformation preventing projection is provided in the cavity of the mold forming the tip of the bent piece to reduce the mold clamping pressure of the mold or to separate the fixed mold portion and the movable mold portion. When
It is characterized in that the deformation preventing projection prevents elastic deformation of the bent piece.

According to a second aspect of the present invention, there is provided the in-mold coating molding method according to the first aspect, wherein the resin molded product is formed in a long shape, and the bent piece is formed of the resin molded product. Are formed so as to extend along the longitudinal direction of the bent piece, and the deformation-preventing projection is a deformation-preventing ridge extending longitudinally along the tip edge of the bent piece.

According to a third aspect of the present invention, there is provided the in-mold coating forming method according to the first or second aspect, wherein the deformation preventing protrusion is provided between the front and rear ends of the bent piece. Are formed so as to be connected to each other.

(Operation) According to the first aspect of the present invention, the tip of the bent piece of the molded resin article is fitted with the deformation preventing projection of the mold. For this reason, it is possible to reduce the mold clamping pressure of the mold, or to easily reduce the trouble caused by the molding shrinkage of the resin molded product immediately after the fixed mold portion and the movable mold portion are separated from each other. . That is, a resin molded product mainly composed of a thermoplastic resin causes an elastic deformation due to molding shrinkage due to a sudden decrease in the mold clamping pressure. This elastic deformation appears most remarkably in the bent portion constituting the base end of the bent piece, and it becomes extremely difficult to bend the bent piece at a desired angle.

On the other hand, according to the present invention, since the deformation preventing projection is provided for bringing the tip of the bent piece into close contact with the mold, the elastic deformation of the bent piece is prevented. Has become. Therefore, since it is easy to maintain a constant gap formed between the surface of the resin molded product and the cavity of the movable mold portion after the mold clamping pressure of the mold is reduced, the resin molded product It is possible to easily form a uniform coating layer on the surface of.

According to the second aspect of the present invention, an in-mold coated molded product in which a uniform coating layer is formed on the surface of a long resin molded product provided with a bent piece extending in the longitudinal direction can be easily and easily obtained. It becomes possible to manufacture to quality. That is, since the deformation preventing ridge of the mold is formed so as to extend in the longitudinal direction of the bent piece, elastic deformation of the bent piece is extremely effectively prevented, and a uniform coating layer is formed on the surface of the bent piece. It is easy to form.

According to the third aspect of the present invention, since the deformation preventing projection is formed so as to connect the front and rear ends of the bent piece, the elastic deformation of the bent piece is prevented over the entire bent piece. Becomes possible. Furthermore, when releasing the in-mold coated molded product from the inside of the mold after the production, the mold can be released very easily by sliding along the deformation preventing projection.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 2, a long product 11 as an in-mold coating molded product includes a substrate 12 as a resin molded product formed into a long shape by a synthetic resin (thermoplastic resin), And a coating layer 13 that covers the surface (upper surface and both side surfaces).

The base material 12 has a base body 15 formed in the shape of a rectangular plate and bent pieces extending in the front-rear direction along both side edges of the base body 15 and bent downward. 16 and a substantially U-shaped cross section. Each bent piece 16 extends so as to connect the front and rear ends thereof over the entire longitudinal side edge of the base material body 15. Further, the outer surface of the bent piece 16 is disposed so as to intersect at an obtuse angle with respect to the upper end surface of the base material main body 15, and spreads slightly outward toward the lower end side as compared with the upper end side. It is formed as follows. At the base end (upper end) of each bent piece 16, there is provided a bent part 17 extending linearly along the longitudinal direction of the base material body 15.

On the other hand, the distal end surface of each bent piece 16 is formed so as to be parallel to the upper end surface of the base body 15. A pair of concave grooves 18 extending in the front-rear direction are formed in the distal end surfaces of the bent pieces 16. Each groove 18
Along the entire longitudinal side edge of the bent piece 16, it extends so as to connect the front and rear ends thereof, and extends in a direction perpendicular to the distal end face of the bent piece 16 and the upper end face of the base body 15. It is recessed as follows.

Next, a method of manufacturing the long product 11 will be described. As schematically shown in FIG. 1A, an in-mold coating forming die 21 for manufacturing the long product 11 includes a fixed die portion 22 and a movable die portion 23. A cavity (engraving surface) having the shape of the back surface (non-design surface) of the base material 12 is formed at the center of the fixed mold portion 22, and one end (front end or rear end) of the cavity is formed. Is provided with a resin injection gate (not shown). A pair of deformation preventing ridges 24 for forming the concave groove 18 of the base material 12 are formed in the cavity of the fixed mold portion 22 so as to extend in the front-rear direction.

On the other hand, the movable mold portion 23 has a cavity (engraving surface) in the shape of the surface (design surface) of the base material 12, and is vertically clamped with respect to the fixed mold portion 22. It is configured to be able to open. Also,
At one end (front end or rear end) of the movable mold portion 23, a coating material injection port (not shown) for injecting a coating material into the cavity is provided.

When the long product 11 is manufactured by using the mold 21 for coating in a mold, first, as shown in FIG. 1A, a fixed mold portion 22 and a movable mold portion 22 are formed. With the mold 23 clamped, the molten resin is injected into the cavity from the resin injection gate, and then cooled and cured to form the base material 12.

Next, the movable mold part 23 is slightly moved upward to open the mold by a predetermined amount. At this time, as shown in FIG. 2 (b), a coating agent is injected between the surface (design surface) of the molded base material 12 and the engraved surface of the movable mold part 23 to form the coating layer 1.
A gap 30 is formed to form the gap 3. The gap 30 is formed so that the bent piece 16 of the base material 12 is slightly widened toward the lower end, so that the gap 30 is wide on the upper surface of the base material 12 and narrow on the side surface of the base material 12. . That is, when the movable mold part 23 is opened by a predetermined amount as described above, the gap 3 formed by the upper end surface of the base body 15 and the upper surface of the cavity of the movable mold part 23.
Oa is wider than a gap 30b formed by the outer side surface of the bent piece 16 and the side surface of the cavity of the movable mold part 23. The gap 30a is held at a constant interval between the upper end surface of the base body 15 and the upper surface of the cavity of the movable mold part 23.

At this time, the bent piece 16 of the base material 12 is used.
As a result, a force for elastically deforming (molding shrink) outward (obliquely upward) around the bent portion 17 is applied with a sudden decrease in the mold clamping pressure of the in-mold coating forming mold 21. However, since the deformation preventing ridge 24 of the fixed mold portion 22 is fitted into the concave groove 18, the bent piece 16
, Its elastic deformation is suppressed against the molding shrinkage force. For this reason, the entire outer surface (design surface) of the bent piece 16 is not moved and the gap 30b is not narrowed.
The third cavity is kept at a constant distance.

Subsequently, a coating material is injected into the gap 30 from a coating material injection port. At this time, the coating material is formed on the upper surface of the substrate 12 by a relatively wide gap 30a.
Through the base material 12 and quickly spread from one end to the other end, and on the side surface of the base material 12 from the upper end to the lower end of the bent piece 16 through the gap 30b. It spreads and spreads at a slow speed.

Finally, after the coating agent is cooled and hardened to form a coating layer 13 on the surface of the substrate 12, the movable mold portion 23 is opened, and the deformation preventing ridges of the fixed mold portion 22 are opened. The long product 11 is released while sliding along 24. Further, an excess lump of the coating agent extending downward from the lower edge of both sides of the long product 11 is cut off along the distal end surface of the bent piece 16.

The effects exerted by the above embodiment will be described below. In the mold coating method of the embodiment, the base material 12 is injection-molded in the mold coating mold 21 having the fixed mold portion 22 and the movable mold portion 23, and then the fixed mold portion 22 is formed. And the movable mold part 23 are separated from each other, and a coating agent is injected into a gap 30 between the surface (design surface) of the base material 12 and the cavity of the movable mold part 23 to be cured. Further, the substrate 12
The bent piece 16 is provided on the base member, and a deformation preventing ridge 24 is projected from a cavity of the fixed mold part 22 forming the tip of the bent piece 16. Therefore, when the coating agent is injected between the surface of the base material 12 and the cavity of the movable mold part 23, the deformation preventing ridge 24 is engaged with the tip of the bent piece 16. Therefore, elastic deformation of the bent piece 16 around the bent portion 17 can be easily prevented. Accordingly, the coating layer 13 having a uniform thickness and a very high designability is formed on the surface of the substrate 12, particularly on the outer surface of the bent piece 16.
Can be easily formed.

In the long product 11 of the embodiment, the base material 12 is formed in a long shape, and the bent piece 16 is formed so as to extend along the longitudinal direction of the base material 12. Further, the mold 21 for in-mold coating forming is formed such that the deformation preventing ridge 24 provided on the fixed mold portion 22 extends in the longitudinal direction along the leading edge of the bent piece 16. For this reason,
When the coating agent is injected between the surface of the base member 12 and the cavity of the movable mold part 23, the deformation preventing ridges 24 extending in the longitudinal direction of the bent piece 16 significantly reduce the elastic deformation of the bent piece 16. Can be prevented.

Further, the deformation preventing ridge 24 is formed by the bent piece 1
Because it is formed so as to connect the front and rear ends of 6,
The elastic deformation can be prevented over the entire bent piece 16. Further, at this time, when the long product 11 is released from the inside of the in-mold coating molding die 21, the long product 11 is extremely easily released by sliding along the deformation preventing ridge 24. It is possible.

The present embodiment can be embodied with the following modifications. -Instead of providing the deformation preventing ridge 24 on the fixed mold portion 22, a projection, a projection, a grain, or a rough surface may be provided. Even with such a configuration, the elastic deformation of the bending piece 16 can be prevented.

Instead of providing the concave groove 18 so as to connect between the front and rear ends of the bent piece 16, the concave groove 18 is provided only in the middle of the bent piece 16 in the longitudinal direction, or is provided by being divided into a plurality of pieces. You may.

One or three or more concave grooves 18 may be provided in each bent piece 16. The bent piece 16 may be provided only on one side of the base body 15. By making the length of the bent piece 16 shorter, the bent piece 16 may be formed as a thick-walled portion-like structure protruding along the side edge of the base body 15.

A slide core is provided in the mold 21 for forming the inner coating, and the movable mold part 23 is opened by a predetermined amount to form the gap 30.
Is formed, the gap between the parting surfaces (PL surfaces) formed below the gap 30b is closed by the slide core. At this time, the bent piece 16 may be formed so as to intersect the base body 15 at right angles or at an acute angle. That is, the bent portion 17 may be an undercut portion formed in an overhang shape.

Instead of forming the gap 30 by opening the movable mold part 23 by a predetermined amount, the pressure of the base 12 is reduced while the clamping pressure of the movable mold part 23 on the fixed mold part 22 is reduced. The coating material may be injected between the surface and the cavity of the movable mold part 23. At this time,
The bent piece 16 may be formed so as to intersect the base body 15 at right angles or at an acute angle.

The substrate 12 may be formed by injection compression molding or injection press molding. Further, technical ideas that can be grasped from the embodiment will be described below.

The method according to any one of claims 1 to 3, wherein the outer surface of the bent piece is formed so as to expand outward toward the tip end. Molding method. With this configuration, the configuration of the mold can be easily simplified.

An in-mold coating molded article manufactured by using the in-mold coating molding method according to any one of claims 1 to 3, wherein a bent piece bent at a predetermined angle is attached to the resin molded article. An in-mold coated molded product characterized in that a concave groove is formed at the tip of the bent piece and a substantially uniform coating layer is formed on the surface of the resin molded product.

A mold for in-mold coating molding used in the in-mold coating molding method according to any one of claims 1 to 3, comprising a fixed mold part and a movable mold part. In a state in which the mold portion is clamped, the resin molded article having the bent piece is formed to be molded, and the clamping pressure of both mold portions is reduced or the fixed mold portion and the movable mold portion are formed. In such a state, the coating agent is injected between the surface of the molded resin article and the cavity of the movable mold part, and the tip of the bent piece of the molded resin article is formed. A mold for in-mold coating molding, wherein a deformation preventing projection for preventing elastic deformation of a bent piece is provided in a cavity of a fixed mold part.

[0034]

As described above in detail, according to the present invention, the following effects can be obtained. According to the in-mold coating molding method of the invention as set forth in claims 1 to 3, when the coating agent is injected between the surface of the resin molded product and the cavity of the mold, elastic deformation of the bent piece is suppressed. As a result, a coating layer having high designability can be easily formed on the surface of the resin molded product.

[Brief description of the drawings]

1A and 1B are cross-sectional views schematically showing a mold for in-mold coating forming according to an embodiment.

FIG. 2 is a perspective view showing a long product of the embodiment.

[Explanation of symbols]

11 ... Long product as an in-mold coating molded product, 12 ... Base material as a resin molded product, 13 ... Coating layer, 16 ... Bending piece, 21 ...
Mold for in-mold coating molding as a mold, 22 ... fixed mold part,
23: moving mold part, 24: deformation preventing ridge, 30, 30
a, 30b: gaps between the surface of the resin molded product and the cavity of the mold.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masao Kobayashi 1 Ochiai Ogata, Nagasuga-cho, Nishi-Kasugai-gun, Aichi Prefecture Toyoda Gosei Co., Ltd. (72) Inventor Sadao Nada 1 Ochiai-Ogata, Kasuga-cho, Nishikasugai-gun, Aichi F term (reference) 4F202 AD11 AG03 AG23 AG28 CA11 CB01 CK11 4F206 AD11 AG03 AG23 AG28 JA07 JB28 JL02 JM05 JM06 JN25 JN35 JQ81

Claims (3)

[Claims] 1. After a resin molded article is molded in a mold having a fixed mold section and a movable mold section, the mold clamping pressure of the mold is reduced or the fixed mold section and the movable mold section are reduced. The coating layer was formed on the surface of the resin molded product in the same mold by injecting and curing a coating agent between the surface of the resin molded product and the cavity of the movable mold part. In the in-mold coating molding method for producing an in-mold coating molded product, a bent piece is provided in the resin molded product, and a deformation preventing projection is provided in a cavity of a mold forming a tip portion of the bent piece, Wherein the mold preventing pressure is reduced or the fixed mold portion and the movable mold portion are separated from each other, so that the deformation preventing protrusion prevents elastic deformation of the bent piece. Molding method. 2. The in-mold coating molding method according to claim 1, wherein the resin molded product is formed in a long shape, and the bent piece is formed so as to extend along a longitudinal direction of the resin molded product. An in-mold coating forming method, wherein the deformation preventing protrusion is a deformation preventing protrusion extending in a longitudinal direction along a leading edge of the bent piece. 3. The in-mold coating forming method according to claim 1, wherein the deformation preventing projection is formed so as to connect between front and rear ends of the bent piece. Coating molding method.