JP2002234050A - Method for producing foamed molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prove a method for producing a foamed molding which can improve the quality of the design surface of the injected foamed molding and the adhesion between the base material of the molding and a coating agent. SOLUTION: After a side molding base material 2 is formed by injection foaming molding, a lower mold 5 is brought down to inject a coating agent solution, and a space is formed between the cavity 6 surface of an upper mold 4 and the surface of the side molding base material 2. The coating agent solution is packed from a coating agent injection device 21 into the space through a coating gate 8. After that, before the coating agent is cured completely, mold clamping is done while the lower mold 5 is brought up, and the coating agent on the surface of the base material 2 is pressed to the cavity 6 surface so that the surface of the coating part 2a of a side molding 1 is smoothed. After the coating part 2a is cured completely, a mold 3 is opened, and the side molding 1 is taken out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a foamed molded product, and more particularly to a method for producing a foamed molded product suitable as a resin product attached to an automobile.

[0002]

2. Description of the Related Art Currently, many exterior resin products are attached to vehicles, and one of the exterior resin products is one of them.
For example, there is a side mall. Generally, a side molding is used for the purpose of protecting and decorating a vehicle body, and is attached to a side surface of a body of a vehicle.

Conventionally, a long side molding has been manufactured by an injection molding method or an extrusion molding method using a mold.
If the cross-sectional shape of the side molding is constant, it can be formed by an extrusion molding method. However, resin products whose exterior cross-sectional shape of a vehicle exterior resin product is not constant are formed by an injection molding method. However, since a solid side molding which is entirely filled with non-foamed resin is heavy in weight, there is foam molding (including a foaming agent) as a means for ensuring lightweight and high rigidity. Injection molded products are generally subjected to coating treatment such as painting. Then, after the side molding base material formed of the foamed resin is removed from the mold, by a spray gun,
A paint is applied to the surface of the side molding base material to form a side molding.

FIG. 4 shows a side molding to which a paint is applied by a spray gun. FIG. 4 is a schematic diagram in which the surface of the side molding base material formed by foam molding is coated with the paint, and the painted portion to which the paint is applied is thickly shown for easy understanding. As described above, when the coating surface of the side molding is enlarged, in the case of coating with the spray gun, the unevenness of the surface of the side molding base material 50 by foam molding affects the surface of the coating portion 51. This is because, due to the low internal pressure of the bubble portion, the side molding base material 50 by foam molding is not uniformly and strongly pressed against the cavity surface, and it is difficult to smooth the surface of the side molding base material 50. This is because even coating with a spray gun does not allow uniform coating. In addition, since the paint is sucked into the gaps between the cells of the foam molded article, irregularities are significantly formed on the painted surface of the foam molded article.

[0005]

As described above, the surface of the foam molded article base material has low smoothness, and it is difficult to secure a smooth surface even if surface treatment is performed. Therefore, even if the surface of the foamed molded product substrate is not smoothened, even if a paint is applied, the painted surface of the foamed molded product substrate will have irregularities, and exterior resin products that require appearance quality are , Was difficult to apply. The same can be said for the case where the surface treatment is performed with a coating agent other than the paint.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a method of manufacturing a foam molded article which can improve the design quality of an injection foam molded article.

[0007]

According to the first aspect of the present invention, there is provided a method for producing a foamed molded article, wherein a film is formed on a foamed molded article substrate in a cavity of a mold. A mold closing step, an injection foaming step, a step of slightly opening the mold after the foaming is completed or a step of loosening the mold, an injection step of injecting a coating solution into the cavity of the mold, and a coating agent. Re-clamping process before the is completely cured,
Opening the mold after curing of the coating agent and taking out the foam molded article.

According to the present invention, the cavity surface is transferred to the surface of the foamed molded product by the coating solution in the mold being pressed against the cavity surface during the re-clamping step. Therefore, the quality of the design surface of the foam molded article is improved. In addition, at the time of re-clamping, the coating material enters the fine irregularities on the surface of the foam molded product base due to an increase in the internal pressure of the coating material in the mold. Anchor effect) is improved. That is, peeling of the film is prevented.

According to a second aspect of the present invention, in the first aspect of the invention, the foam molded article is a long product.
ADVANTAGE OF THE INVENTION According to this invention, even if a long object has a complicated shape, the quality of the design surface of an injection foam molded article is improved.

According to a third aspect of the present invention, in the first or second aspect, the gold foam molded article is:
It is a side mall. ADVANTAGE OF THE INVENTION According to this invention, the side molding suitable as an exterior resin product of vehicles can be easily shape | molded.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment in which the present invention is embodied in a side molding will be described below with reference to FIGS.

As shown in FIG. 2, a side molding 1 is composed of a side molding base 2 as a foam molding base and a coating portion 2a as a coating made of a coating material as a coating agent applied to the surface thereof. Is formed. Side molding base material 2
Is made of a foamed resin. As a resin used for the side molding base material 2, for example, a thermoplastic resin PP
(Polypropylene), PE (polyethylene), PUR
(Polyurethane) and TPE (thermoplastic elastomer).

As the foaming agent, either a solvent-type foaming agent or a decomposition-type foaming agent is used. Solvent type foaming agents, for example, propane, butane, benzene, toluene,
Methylene chloride and the like are used, and as the decomposable foaming agent, for example, diazoaminobenzene as an azo compound, benzenesulfonyl humanazide as a sulfonyl compound and the like are used. By the combination of these resins and a foaming agent, nitrogen gas or carbon dioxide gas is generated, and the foamed resin is obtained.

The reactive coating solution includes, for example, urethane acrylate oligomer, epoxy acrylate oligomer, styrene, zinc stearate, titanium oxide, carbon black, 8% cobalt octoate, t
A mixture of -butylperoxybenzoate and the like is used.

As shown in FIGS. 1 (a) to 1 (c), an injection molding apparatus used for manufacturing the side molding 1 has a mold 3
The fixed upper mold 4 and the movable lower mold 5 are provided so as to face each other. The mold 3 is configured such that the lower mold 5 is moved upward from the state in which the lower mold 5 of the movable mold is opened, and is clamped.

The upper mold 4 has a recess 4a.
The space including the concave portion 4 a sandwiched between the upper mold 4 and the lower mold 5 becomes a cavity 6 for forming the side molding 1. In the mold 3, a gate 7 and a painting gate 8 communicating with the cavity 6 are formed. Also, the recess 4 of the upper mold 4
A discharge hole (not shown) is formed in a.

As shown in FIG. 1A, the foamed resin from the foamed resin injection device 20 is configured to be able to be injected into the cavity 6 through the gate 7. Further, when the lower mold 5 is moved downward in the drawing, the coating gate 8 is configured to communicate with the cavity 6, and at this time, the coating solution from the coating material injection device 21 is supplied to the coating gate. It is configured to be injected into the cavity 6 through 8. In addition,
The gate 7 and the coating gate 8 are formed not in the same plane but in shifted positions in the longitudinal direction of the mold 3.

Next, a method of manufacturing the side molding 1 will be described. First, the mold 3 is opened and a release material is applied to the inner wall surface of the cavity 6. Next, as shown in FIG.
The mold 3 is clamped with the upper mold 4 and the lower mold 5 closed (mold clamping step).

Next, while the mold 3 is kept horizontal, the foamed resin is injected into the cavity 6 from the foamed resin injection device 20 through the gate 7, and the side molding base material 2 having the same shape as the cavity 6 is formed. Injection foaming is performed (injection foaming process).

As shown in FIG. 1B, after foaming of the foamed resin forming the side molding base material 2 is completed, the mold 3 injects a coating solution between the upper mold 4 and the lower mold 5. In order to form a space for the lower mold 5, the lower mold 5 is moved downward and is opened slightly. Thereby, the cavity 6 of the upper die 4
A space is provided between the surface and the surface of the side molding base material 2 (mold opening step). In FIG. 1B, the side molding base 2 and the surface of the cavity 6 are shown extremely separated in order to make it easy to see how the upper mold 4 and the lower mold 5 are separated. FIG. 1B shows a cross section at a location different from FIG. 1A.

When the lower mold 5 is moved downward, the coating gate 8 can be communicated with the cavity 6, and the coating material injection device 21 is connected to the side surface of the cavity 6 through the coating gate 8 through the coating gate 8. A space provided on the surface of the material 2 is filled with a coating solution (coating injection step). At this time, the air in the cavity 6 is discharged to the outside of the cavity 6 through the discharge hole.

As shown in FIG. 1C, after filling the coating solution and before the coating is completely cured, the side molding substrate 2
Lower mold 5 again so as to narrow the gap between
Is moved upward (re-clamping step).
At that time, the coating material on the surface of the side molding base material 2 is pressed against the surface of the cavity 6, and the surface of the coating portion 2a of the side molding 1 is smoothed. Then, after the coating portion 2a is completely cured, the mold 3 is opened, and the side molding 1 is taken out (foam molded product taking out step).

As shown in FIG. 3, even if the side molding 1 has irregularities formed by foam molding on the surface of the side molding base material 2, the surface of the cavity 6 is transferred to the coating portion 2a to achieve high smoothness. The design of the painted part 2a (color tone,
The side molding 1 having excellent gloss and the like is formed.

This embodiment has the following effects. (1) After filling the coating solution, the mold is re-clamped before the coating is completely cured, and the inner surface shape of the cavity 6 is transferred to the coating portion 2a of the side molding 1, so that the design of the side molding 1 Surface quality can be improved.

(2) Since the coating material enters the fine irregularities on the surface of the side molding base material 2 formed of the foamed resin, the side effect is achieved by the anchor effect compared to when the coating material is applied on a smooth surface. The adhesion strength between the molding substrate 2 and the coating agent can be improved.

(3) Since the coating solution enters into minute irregularities on the surface of the side molding base material 2 formed by foam molding due to an increase in internal pressure due to re-clamping after filling the coating solution, the side molding base material 2 and the coating agent can be further improved in adhesion strength. That is, it is possible to prevent the peeling of the coating portion 2a as the coating of the side molding 1.

(4) In order to form a space for injecting the coating solution, the lower mold 5 is moved downward, and the mold 3 is opened slightly open. Therefore, a predetermined amount of space can be easily provided between the surface of the cavity 6 of the upper die 4 and the surface of the side molding base material 2.

(5) Side molding base material 2 by foam molding
Even if the surface is closed cells or open cells, the surface of the coating portion 2a can be smoothed by adjusting the injection amount of the coating solution.

(6) Since the coating solution is applied in the mold and the surface of the coating portion 2a of the side molding 1 is smoothed, the surface of the side molding 1 need not be adjusted by polishing or the like. it can.

(7) The side molding 1 can be reduced in weight by using a foamed resin having a lower density as compared with a solid body as a material for forming the side molding 1. (8) By performing injection molding, a resin product having a complicated shape can be handled. In addition, variation in dimensions can be suppressed as compared with extrusion molding.

The embodiment is not limited to the above, and may be modified as follows, for example. In the above embodiment, the upper mold 4 and the lower mold 5 are opened in a slightly opened state after the foaming of the foamed resin forming the side molding base material 2 is completed. The state in which the mold is loosened, that is, the state in which the pressure applied to the lower mold 5 is reduced, may be changed. Also in this case, the coating solution can be injected into the cavity 6.

In the above embodiment, injection foaming was used, but two or more types of monomers were mixed in a head and simultaneously injected into a mold to complete a polymerization reaction in the mold to produce a product. You may change to the obtained reaction injection foam molding.
Also in this case, the coating solution can be applied to the side molding base material 2 formed by the reaction injection foam molding.

In the above-described embodiment, the gate 7 into which the foaming resin is injected and the coating gate 8 into which the coating solution is injected are different from each other. However, the foaming resin and the coating solution are supplied through one gate. , The cavity 6 may be filled. In the case of such a configuration, by setting the injection point at one position, it is possible to reduce a defect phenomenon formed on the injection molded product.

The injection foam molded article molded according to the above embodiment may be formed of another member, such as an instrument panel or a bumper, instead of the side molding. In this case, since injection molding can cope with a complicated shape, an instrument panel, a bumper, and the like can be easily manufactured.

It may be used for manufacturing resin products other than those for vehicles. Also in this case, a resin product requiring appearance quality can be easily manufactured. -The components of the coating solution may be changed as appropriate. In this case, a suitable color, a suitable coating thickness, and the like can be adjusted.

The coating solution need not be a paint. In this case, the injection molded article can be subjected to a surface treatment according to its use. -You may change a solvent type foaming agent into a decomposition type foaming agent. Alternatively, nitrogen gas or the like may be used as a uniform fine bubble dispersion at a predetermined volume ratio, and this may be expanded and foamed under a reduced pressure atmosphere. As long as it is a substance that forms a foamed resin, the combination of the resin and the foaming agent may be changed as appropriate to be implemented. In such a configuration, a foamed resin can be selected according to the purpose of the member, and the manufacturing cost can be reduced.

The state of the cells of the foamed resin may be closed cells or open cells. Also in this case, the anchor effect between the coating agent and the side molding base material 2 can be improved.

Next, the technical ideas that can be grasped from the above embodiment will be described below. (1) A method for producing a foamed molded product in which a film is formed on a foamed molded product substrate in a cavity of a mold, comprising: a mold clamping step;
Injection foaming process, mold opening process for slightly opening the mold after foaming is completed, injection process for injecting the coating solution into the cavity of the mold, and re-clamping process before the coating material is completely cured And a step of taking out the foamed molded product by opening the mold after curing of the coating agent.

(2) A foam molded article having a coating formed on the surface thereof by applying a coating solution in the mold to the surface of the foam molded article base material that has been injection foamed and molded in the cavity of the mold.

(3) In the invention according to any one of claims 1 to 3, the injection foam molding is reaction injection foam molding.

[0041]

As described above in detail, according to the first to third aspects of the present invention, the quality of the design surface of the injection foam molded article can be improved, and the injection foam molded article base material and the coating agent can be improved. Adhesion can be improved.

[Brief description of the drawings]

1A is a schematic cross-sectional view of an injection mold, FIG. 1B is a schematic cross-sectional view showing the operation of injection molding, and FIG. 1C is a schematic cross-sectional view of a re-clamping step.

FIG. 2 is a perspective view of a side molding.

FIG. 3 is a partial schematic sectional view of a side molding.

FIG. 4 is a partial schematic cross-sectional view of a side molding formed by a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Side molding as a foam molded article, 2 ... Side molding base material as a foam molded article base material, 2a ... Coating part as a coating, 3 ... Mold, 6 ... Cavity.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiromi Hinata 1 Ogataai Nagahata, Kasuga-machi, Nishi-Kasugai-gun, Aichi Prefecture Toyoda Gosei Co., Ltd. (72) Inventor Daiichiro Kawashima 1 Ochiai-Cho, Kasuga-cho, Nishikasugai-gun, Aichi Address Toyoda Gosei Co., Ltd. F-term (reference) 4F206 AG20 AH23 AH26 JA04 JB23 JM05 JN33 JQ81

Claims (3)

[Claims] 1. A method for producing a foamed molded product in which a film is formed on a foamed molded product substrate in a cavity of a mold, comprising: a mold clamping step; an injection foaming step; Opening the mold or loosening the mold, injecting the coating solution into the cavity of the mold, re-clamping before the coating is completely cured, and opening the mold after the coating is cured. Removing the foamed molded product by removing the foamed molded product. 2. The method for producing a foamed molded product according to claim 1, wherein the foamed molded product is a long product. 3. The method for producing a foamed molded product according to claim 1, wherein the foamed molded product is a side molding.