JPH06297475A - Manufacture of foam-molded article - Google Patents

Abstract

PURPOSE:To provide a method for efficinetly obtaining fine looking foam-molded article, in which the formation of extended core material is unnecessary and consequently the removal work of the extended core material is unnecessary, and workability is extremely good and no flashs and the like develops, in the closed molding system. CONSTITUTION:Releae film 25 for covering the upper mold parting surface 15a corresponidng to a stock feed hole 16, runner part 17 and gate part 18 is fixed to the end part of core material 22. By arranging the release film and the core material onto an upper mold 12 so as to form the stock feed hole, runner part and gate part between the inner surface of the release film and the inner surface of peripheral edge part of skin in order to form a foam- molded article by integrally expanding the core material and the skin by pouring foaming stock through the stock feed hole between the core material and the skin. After that, the releae film is removed from the foam-molded article.

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 foam-molded product, and more particularly to a method for producing a foam-molded product in which a core material and a skin are integrally formed of a foam resin.

[0002]

2. Description of the Related Art As shown in FIGS. 8 and 9, a general foamed molded article 70 such as an automobile instrument panel is composed of a core material 71, a foamed resin 72 and a skin 73, and has a predetermined panel shape. It is formed in.

Various proposals have hitherto been made as methods for producing such foam-molded articles. For example, (1) a so-called open mold method, in which the outer skin is set in the lower mold of the foaming mold and the core material is set in the upper mold, and the foaming raw material is poured into the cavity in the mold open state and the mold is closed to perform the foaming molding,
(2) Semi-closed to perform foam molding by setting the skin in the lower mold of the foam molding mold and the core material in the upper mold, and then pouring the foaming raw material into the cavity and closing the mold with the upper mold closed to a predetermined position. Molding method (described in Japanese Examined Patent Publication No. 3-75328), and (3) setting the skin on the lower mold of the foaming mold and the core material on the upper mold, respectively, to form a film gate communicating with the cavity in the mold clamped state. There is known a closed mold system (described in Japanese Patent Publication No. 63-28786) in which a foaming raw material is injected from the gate and foam-molded.

However, in the first method, it is necessary to align the upper mold and the lower mold and clamp the mold after the step of injecting the foaming raw material is completed, and it takes a long time to complete the work. . Therefore, the foaming reaction of the foaming raw material progresses before the mold is clamped, and the volume of the foaming raw material may increase, so that the foaming raw material may protrude from the cavity. This protruding foaming raw material wraps around to the back side of the core material and adheres to the molding die and causes defects such as burrs. Therefore, there is a problem that a process for removing burrs from a molded product, a process for cleaning a molding die, and the like are newly added, and work efficiency cannot be improved.

Further, in the second method, the time required for the work from the injection of the foaming raw material to the mold clamping can be shortened, but when the foaming raw material having fast reactivity is used, the mold clamping is not completed. The foaming raw material may start a foaming reaction, and the foam layer may be crushed by the mold clamping, resulting in inconveniences such as cell roughness, lack of wall thickness, and uneven density.

Further, in the third method, since it is necessary to pass the foaming raw material through the narrow film gate, the foaming raw material is adjusted to have a low viscosity and injected into the cavity at a high pressure. At this time, in order to prevent the low-viscosity foaming raw material from entering the back side of the core material, the core material is formed to extend to the rear of the film gate. According to this method, the foaming raw material on the back side of the core material is formed. Although it can be prevented from wrapping around, the extended core material portion must be crushed by a water jet or the like and removed from the product after the product is demolded. Therefore, not only new equipment for performing the removal work is required, but also the loss of the raw material for the removed core material increases, which causes a cost increase. Further, in such a removing operation, the cut surfaces of the core material may become uneven and the crushed core material may adhere to the product, impairing the appearance of the product.

[0007]

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve all of the above-mentioned problems, and in the closed mold system, it is not necessary to extend the core material and remove it. It is an object of the present invention to provide a method for efficiently obtaining a foam-molded article which does not require any workability, has extremely good workability, and has a good appearance without the occurrence of burrs.

[0008]

That is, the present invention is
Close the upper mold with the core material and the lower mold with the epidermis,
The peripheral portion of the skin is sandwiched by the parting surfaces of the upper mold and the lower mold except for the raw material injection port, the runner part and the gate part, and the core material and the skin are sandwiched from the raw material injection port through the runner part and the gate part. In a method for producing a foamed molded product in which a foaming raw material is injected and foamed integrally with a core material and a skin, a release film covering the upper mold parting surface corresponding to the raw material injection port, runner portion and gate portion is provided at a core material end portion. Fixed to, the release film and the core material is placed in the upper mold to form a raw material inlet, a runner portion and a gate portion between the inner surface of the release film and the inner surface of the peripheral portion of the skin, and a foaming raw material from the raw material inlet. The present invention relates to a method for producing a foam-molded article, which comprises injecting between a core material and an epidermis to integrally foam with the core material and the epidermis to form a foamed product, and then removing the release film from the foamed product.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an example of a foam molding die for carrying out the method of manufacturing a foam-molded article of the present invention, FIG. 2 is a cross-sectional view showing the mold clamped state, FIG. 3 is a cross-sectional view showing the main part thereof, and FIG.
Is a cross-sectional view showing other portions, FIG. 5 is a perspective view showing an example of a temporary fixing member, FIG. 6 is a cross-sectional view showing a demolded state of a molded product, and FIG. 7 is a molding obtained by the manufacturing method of the present invention. It is a perspective view showing an example of an article.

1 and 2 show a foaming mold for carrying out the manufacturing method of the present invention. Reference numeral 10 is a foam molding die, 11
Is a lower mold, 12 is an upper mold, 13 is a hinge for opening and closing the upper mold 12 with respect to the lower mold 11, and 14 is a molded product cavity. In this foaming mold 10, a raw material injection port 16 of a foaming material is provided in a part of the parting surface 15 of the lower mold 11 and the upper mold 12, a raw material injection nozzle N is attached, and a runner portion 17 is provided. And, it communicates with the cavity 14 through the gate portion 18. As shown by the chain line in FIG. 7, in this embodiment, the gate portion 1
Reference numeral 8 constitutes a so-called film gate, which is formed in a slit in the longitudinal direction of the back side of the product in the molded product cavity 14.

A skin 21 is formed on the cavity surface of the lower mold 11.
Are arranged. The skin 21 is formed to be slightly larger than the cavity surface, and when the lower mold 11 and the upper mold 12 are closed, the raw material injection port 1 which is a flow path for foaming raw material is formed.
6, the parting surface 15 excluding the runner portion 17 and the gate portion 18 sandwiches the peripheral edge portion 23 of the skin 21.

A core material 22 is arranged on the upper mold 12. Core material 2
The reference numeral 2 is formed of a known hard resin, a metal plate or the like in a predetermined insert shape, and is attached to the cavity surface of the upper mold 12 by a pin member 24. It is not necessary to extend the length of the core member 22 to the rear of the gate unlike the one used in the conventional method, and it is preferable that the core member 22 is formed in the shape of the core member to be arranged in the product. As understood from FIGS. 3 and 4, a groove portion 27 is provided in the end surface portion of the core material 22. In this groove 27,
The release film 25 is temporarily fixed by the temporary fixing member 30.

The release film 25 is the raw material inlet 1
6, to prevent the foaming raw material passing therethrough from wrapping around to the back side of the core material 22 by covering the upper parting surface 15a forming the runner portion 17 and the gate portion 18, and having a thickness of about 0.2 to 2 mm. Polyethylene or polypropylene films of are preferred. Further, this release film 25 is
Raw material injection port 16 of the die where the film is placed in advance,
It is preferable to form the runner portion 17 and the gate portion 18 slightly larger than the size. As a result, when the mold is clamped, the mold part is reliably covered with the release film, and the foaming raw material can be prevented from adhering to the mold surface.

In the upper die 12, a release film 25
An appropriate number of suction holes 26 are provided in the portion corresponding to. This suction hole 26 is connected to a vacuum device or the like (not shown) outside the machine so that the mold release film 25 temporarily fixed to the end of the core material is sucked and fixed to the upper mold parting surface 15a during molding. It has become.

The temporary fixing member 30 is made of a synthetic resin having rubber elasticity, etc., and as can be better understood from FIG. 5, the convex portion 31 and the end portion of the core member 22 provided continuously from the convex portion 31. And a projecting portion 32 having a shape projecting from.
The convex portion 31 is formed in a shape capable of engaging with the groove portion 27 of the core material 22, and by engaging with the groove portion 27 of the core material 22 via the end portion of the release film 25, the mold release The film 25 is temporarily fixed to the end of the core material 22. Also, FIG.
As will be understood from FIG.
The protrusion 32 is configured to protrude toward the gate portion 18 of the mold when it is attached to the upper mold 12 and is fixed to the upper mold 12.

The protruding portion 32 is for controlling the amount of foaming raw material flowing into the cavity 14. In this embodiment, the protruding amount of the protruding portion 32 is the core material 22.
Partially changed along the edge of. Therefore,
As shown in FIG. 3, in the portion 32a of the protruding portion 32 where the protruding amount is small, the flow path of the foaming raw material that continues from the gate portion 18 to the cavity 14 is configured to be wide. Also, FIG.
As shown in (3), in the portion 32b having a large amount of protrusion, the distance from the skin 21 is close, and the flow path leading to the cavity 14 is narrowed.

According to this structure, for example, when a molded product as shown in FIG. 7 is manufactured, the portion A where the distance from the gate portion 18 to the cavity end is long and the portion B where the distance is short are used in the resin flow direction. The amount is different. Therefore, in the portion A, as shown in FIG. 3, the protrusion amount of the protrusion 32 is reduced so that the resin flows smoothly. On the other hand, in the portion B, as shown in FIG. 4, the protrusion amount of the protrusion 32 is increased to limit the flow of resin. This makes it possible to finely control the resin flow rate corresponding to the shape of the cavity and prevent voids, lack of walls, or cell roughness from occurring in the molded product.

At the time of molding, the outer skin 21 is attached to the lower mold 11.
The core material 22 to which the release film 25 is temporarily fixed is disposed on the upper mold 12. Then, the release film 25 is adsorbed and fixed to the suction holes 26 of the upper mold by a vacuum device (not shown), the parting surface 15a of the upper mold 12 is covered, and the peripheral edge portion 23 of the outer skin 21 is covered with a mold member. The raw material injection nozzle N is sandwiched by the sealing surface 15 and the raw material injection nozzle N is attached.
The mold is clamped in the state of being placed in No. 6. Thereafter, as shown in FIG. 2, the foaming raw material U is injected from the raw material injection port 16 between the skin 21 and the core material 22.

The foaming raw material U injected is the runner portion 1 described above.
7 and the gate portion 18 to fill the cavity 14, and foam-molded integrally with the skin 21 and the core material 22.
As described above, in the upper mold 12, the part from the raw material injection port 16 to the end of the core material 22 is covered with the release film 25. Therefore, the injected foaming raw material U is prevented from flowing around to the back side of the core material 22. Can be prevented. Therefore, burrs etc. will not occur and the appearance of the product will not be spoiled, and
Since the foaming raw material does not adhere to the molding die, it is possible to greatly reduce the labor required for the work such as cleaning the die. Further, the distance between the temporary fixing member 30 and the outer skin 21 in the gate portion 18 can be adjusted by changing the protrusion amount of the protrusions 32a and 32b, and the distance can be injected according to the shape of the molded product cavity 14. The amount of the foaming raw material U can be delicately controlled to obtain a highly accurate product.

After completion of the foaming reaction, the mold M is opened and the molded product M is demolded as shown in FIG. Reference numeral 28 is a foam molded from the foaming raw material U. By removing the release film 25 and the temporary fixing member 30 attached to the molded product M and cutting the outer peripheral edge portion 23 along the shape of the molded product, the intended foam molded product is obtained. The removed temporary fixing member 30 can be collected and reused.

[0021]

As shown and described above, according to the method for producing a foamed molded article of the present invention, in the closed mold system, the foaming raw material does not wrap around to the back side of the core material,
It is possible to prevent the occurrence of burrs and obtain a highly accurate product.
Therefore, it is not necessary to extend and form the core material, so that there is no loss of raw material. Further, there is no need for an operation and a device for removing the extended core material portion from the product, so that the production efficiency can be increased and the manufacturing cost can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a foam molding die for carrying out a method for manufacturing a foam molded article of the present invention.

FIG. 2 is a cross-sectional view showing the mold clamped state.

FIG. 3 is a cross-sectional view showing a main part thereof.

FIG. 4 is a cross-sectional view showing another portion.

FIG. 5 is a perspective view showing an example of a temporary fixing member.

FIG. 6 is a cross-sectional view showing a demolded state of a molded product.

FIG. 7 is a perspective view showing an example of a molded product obtained by the manufacturing method of the present invention.

FIG. 8 is a perspective view showing an example of a general foam-molded article.

FIG. 9 is a sectional view taken along the line 9-9.

[Explanation of symbols]

 10 Foaming Mold 11 Lower Mold 12 Upper Mold 15 Parting Surface 16 Raw Material Injecting Port 17 Runner Part 18 Gate Part 21 Skin 22 Core Material 25 Release Film 27 Groove 30 Temporary Fixing Member 31 Convex Part 32 Projecting Part U Foaming Raw Material

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B29L 31:58 4F

Claims (2)

[Claims] 1. A parting surface of an upper mold and a lower mold except for a raw material injection port, a runner part and a gate part at the peripheral part of the epidermis, the upper mold having a core material and a lower mold having a skin are closed. In the method for producing a foam-molded article in which a foaming raw material is injected between the core material and the skin through the runner part and the gate part from the raw material injection port to foam integrally with the core material and the skin, the raw material injection port , A release film covering the parting surface of the upper die corresponding to the runner portion and the gate portion is fixed to the end of the core material, and the release film and the core material are arranged on the upper die to form the inner surface of the release film and the peripheral edge portion of the skin. A raw material inlet, a runner portion and a gate portion are formed between the inner surfaces, and a foaming raw material is injected from the raw material inlet between the core material and the skin to foam the core material and the skin integrally to form a foamed product. Foaming characterized by removing the release film from the foam Method for producing a molded article. 2. The temporary fixing member for temporarily fixing an end of a release film to an end of a core material according to claim 1, wherein the temporary fixing member is attachable to and detachable from the end of the core material so that a part thereof projects from the end of the core material. While temporarily attaching the release film by attaching to, by changing the projection amount of the temporary fixing member partially along the end of the core material to change the distance between the temporary fixing member and the skin,
A method for producing a foam-molded article, comprising controlling an injection amount of a foaming raw material injected between the skin and the core material.