JPH06344358A - Base material of foam molded article and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a base material, with which foaming stock can be prevented from adhering to a cover mold and, at the same time, enough degassing is performed under the condition that the development of burr is suppressed, and the manufacturing method of a foam molded article by the use of the base material. CONSTITUTION:In a base material 10, which is arranged on one side of a skin 20 and has a foam molding space S formed against the skin 20, sealing surface 12, which comes in tight contact with the peripheral edge of the skin, is provided at the peripheral edge of the base material 10 and on which degassing grooves 14, which communicate the inside and outside of the foam molding space S with each other, are provided. Under the above-mentioned condition, the base material 10 is arranged to a cover mold, while the skin 20 is arranged to a cavity mold, so as to pour foaming stockin the foam molding space S made between the skin and the base material in order to expand the stock under the state that the inside and outside of the foam molding space S communicate with each other through the degassing grooves 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base material for foam-molded articles and a method for producing foam-molded articles.

[0002]

2. Description of the Related Art Foam molded articles, such as instrument panels or console lids of automobiles, in which a foam is provided between a base material and a skin are often manufactured by an integral foam molding method using a foam molding die. . In the integrated foam molding method, a base material (also called an insert) is placed in a lid mold (also called an upper mold), and a skin is placed in a cavity mold (also called a lower mold), and inside the skin. This is a method of injecting a foaming raw material such as a polyurethane raw material so as to integrally foam with the skin and the base material in a foam molding space (cavity) between the skin and the base material.

In this integral foaming method for the skin, the foaming raw material injected into the skin fills the foaming molding space by the foaming reaction, and the foaming pressure at that time causes a part of the foaming raw material to be a lid mold and a cavity mold. Easily leaks to the closing surface and adheres to the closing surface. Moreover, the foaming raw material adhering to the closing surface adheres to the closing surface and hardens, so that it is not easy to remove it from the foaming mold. Therefore, it has been necessary to previously apply a release agent to the foaming mold, especially to the closing surface to prevent the leaked foaming raw material from adhering.

Further, in order to omit the application of the release agent, the end portion of the base material is extended outward and the peripheral edge of the base material and the peripheral edge of the skin are overlapped and sealed to prevent leakage of the foaming raw material. Proposed. However, in that case, since there is no gap between the peripheral edge of the skin and the peripheral edge of the base material, the air in the foam molding space during foaming and the foaming gas generated from the foam raw material cannot escape from the foam molding space to the outside. Enclosed in the body forming space. As a result, the foaming material cannot completely fill the inside of the foam molding space due to the hindrance of air and foaming gas trapped in the foam molding space, and the molded product has a wall thickness or void (air trap). It is likely to occur and cause defective molding.

Therefore, it is conceivable that the foaming mold is designed so that a gap is formed between the skin and the base material, and the degassing at the time of foaming is performed from the gap between the skin and the base material. However, in that case, since the skin formed by slush molding or the skin stretched by vacuum forming has a variation in thickness, the gap between the skin and the base material becomes large and the leakage amount of the foaming raw material increases. As a result, burrs are likely to be formed, or conversely, the gap is reduced, which may result in insufficient degassing.

A method has also been proposed in which a sealing ridge is provided on the base material and the ridge is brought into close contact with the skin to prevent leakage of the foaming raw material (see Japanese Patent Publication No. 4-15091). Also in this case, the degassing becomes insufficient, and the molded product is apt to have a lack of wall or a void.

[0007]

SUMMARY OF THE INVENTION Therefore, the present invention provides a foam base material capable of preventing the foaming raw material from adhering to the lid mold and capable of sufficiently degassing while suppressing the formation of burrs, and Provided is a method for producing a foam-molded article using a base material.

[0008]

According to a first aspect of the present invention, there is provided a base material which is disposed on one side of an outer skin and forms a foam molding space between the outer skin and a seal which is closely adhered to the outer edge of the outer skin. The present invention relates to a base material for a foam-molded article, wherein a surface is provided, and a gas vent groove that communicates the inside and outside of the foam molding space is provided on the sealing surface.

A second aspect of the present invention is to inject a foaming raw material into a skin arranged in a cavity mold, and to form the foaming raw material in the foam molding space between the base arranged in the lid mold and the skin. In the method of manufacturing a foam-molded article that foams integrally with
The base material of the first invention is placed as the base material in the lid mold so that the degassing groove faces the peripheral edge of the skin of the cavity mold, and the sealing surface of the peripheral edge of the base material and the peripheral edge of the skin are brought into close contact with each other to seal. At the same time, the present invention relates to a method for producing a foam-molded article, wherein the foaming raw material is foamed while the inside and outside of the foam molding space are communicated by the gas vent groove.

[0010]

According to the present invention, the base material has a sealing surface on the peripheral edge, and the sealing surface is in close contact with the peripheral edge of the skin to seal the space between the skin and the skin. Therefore, even if there is a variation in the thickness of the skin, reliable sealing can be achieved. . In addition, since a gas vent groove that communicates the inside and outside of the foam molding space is formed on the sealing surface of the base material, the air in the foam molding space and the foaming gas generated from the foaming material when foaming the foaming raw material are formed. The foam can be escaped from the molding space to the outside, and the molded product does not have a wall thickness or void. Moreover, the foaming raw material is less likely to enter the narrow gas vent groove because the viscosity increases and the fluidity decreases due to foaming. Is less likely to leak out of the foam molding space through the gas vent groove. As a result, there is no possibility that the foaming raw material will adhere to the foaming mold and burrs will form.

Further, in the usual integral foam molding,
Temporary deformation may occur in the vicinity of the skin periphery due to variations in skin size, foaming heat of the foaming raw material, foaming pressure, etc., but in the present invention, the skin periphery is brought into close contact with the sealing surface of the base material. Since it is fixed by fixing, deformation is unlikely to occur near the peripheral edge of the epidermis. Therefore, the gas vent groove is not blocked by the deformation near the peripheral edge of the skin, and it is possible to always ensure sufficient gas vent.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. 1 is a cross-sectional perspective view showing an embodiment of a base material according to the present invention, FIG. 2 is a cross-sectional view of a foam-molded product foam-molded using the base material, and FIG. 3 is foam-molding using the base material. FIG. 4 is a cross-sectional view of a foam molding die showing the process, FIG. 4 is a cross-sectional view showing a closed mold state during the foam molding, and FIG.

First, examples of the base material according to the first invention will be described. The base material 10 shown in FIG. 1 forms a part of the foam-molded product 70 shown in FIG. 2, and is used for attaching the foam-molded product 70 or for imparting rigidity to the foam-molded product 70, which will be described later. The epidermis 20 is arranged on one side of the epidermis 20.
A foam molding space S is formed between and. A foaming material is injected into the foam molding space S to form the foam 30 shown in FIG. 2 integrally with the base material 10 and the skin 20.

The base material 10 is made of a hard resin such as a polyphenylene ether resin or an ABS resin, or a fiber reinforced resin thereof, for use as a foam molded article by injection molding or the like.
Shaped according to the shape, etc.
(A portion from the end of the base material to the alternate long and short dash line in FIG. 1) and the gas vent groove 14.

The sealing surface 12 is intended to prevent the foaming raw material from leaking from the base material 10 and the skin peripheral edge 22 by closely adhering to the skin peripheral edge 22 during the production of the foamed molded article.
It is formed with a predetermined width a from the end portion of the base material on the surface facing. The width a of the sealing surface 12 is usually about 15 to 25 mm.
The sealing surface 12 does not have to be provided on the entire circumference of the base material, but may be provided only on a portion where the foaming raw material is likely to leak during the production of the foamed molded product.

The gas vent groove 14 communicates the inside and outside of the foam molding space S at the time of manufacturing the foam molding, and the foam molding space S
The air and the foaming gas are allowed to escape from the foam molding space S to the outside, and are formed on the sealing surface 12.
The degassing groove 14 has a width and a depth of 2 mm to
It is about 6 mm. The length may be from the outer end 12a of the seal surface 12 to the middle of the seal surface 12, but it is preferable that the one end 14a projects into the foam molding space S as in this embodiment. The protrusion amount b (shown in FIG. 5) is preferably about 1 to 5 mm. Further, the gas vent groove 14 does not have to be provided over the entire area of the sealing surface 12, and may be provided only in a portion where gas venting is particularly required. The distance c from the adjacent gas vent groove is 10 to
About 20 mm is preferable. Of course, for the gas vent groove located in the portion where the air and the gas are easily accumulated, the interval of the gas vent groove may be narrowed, and conversely, for the gas vent groove located in the portion where the gas is less likely to accumulate, the interval may be widened. In addition,
The degassing groove 14 is not limited to the concave cross section as in this embodiment, but may be a semicircle or the like.

Next, a method for producing a foam-molded article of the second invention using the above-mentioned substrate will be described with reference to FIGS. 3 to 5. The foaming mold 40 used is a cavity mold 42.
And a lid mold 52, and has a cavity inside.

The cavity mold 42 has a cavity surface 45 inside according to the shape of the foamed molded product. Further, the cavity mold 42 of this embodiment has a split mold 43 at the upper part so that the undercut shape can be eliminated when the foamed molded product is removed from the mold. Of course, the cavity mold that does not have the undercut shape does not have to have the split mold structure. Further, in the split mold 43 portion, a seal portion 46 that sandwiches the skin peripheral edge 22 and the peripheral edge of the base material 10 with the lid mold 52 is formed, and
A skin positioning projection 48 is formed on a mold closing surface 47 with the lid mold. Reference numeral 50 is a hinge for opening and closing the split molds 43 and 44.

On the other hand, the lid mold 52 is attached to the cavity mold 42 by a hinge 54 so that it can be opened and closed. A gap 58 is formed between the mold closing surface 56 of the lid mold and the mold closing surface 47 of the cavity mold when the molds are closed.

The foam mold 40 is opened as shown in FIG. 3, and the skin 20 is placed on the cavity surface 45 of the cavity mold 42. The skin 20 is made of a soft plastic sheet such as vinyl chloride resin or a laminated material in which polyurethane foam and a plastic film are laminated on a fabric, and has a predetermined shape by vacuum forming, slush forming, powder slush forming or sewing according to the material. It is the one that was made. This skin 2
0 has a peripheral edge 22 for sealing and positioning on the outer periphery of the product portion. In the peripheral edge 22, the end portion 23 is arranged on the mold closing surface 47 of the cavity mold, and the inner portion 24 is arranged on the seal portion 46 of the cavity mold. In addition, the peripheral edge 22
A positioning recess 25 is formed in the end portion 23 of the, and the positioning recess 25 is fitted into the cavity-type positioning projection 48 so that the skin 20 is correctly placed on the cavity surface 45. A hole may be opened instead of the positioning recess 25.

On the other hand, the base material 10 is attached to the lid mold 52 so that the sealing surface 12 and the gas vent groove 14 are on the side of the cavity mold 42. The base material is attached by various known means, but as an example, a clip (not shown) provided on the base material is fitted into a recess (not shown) formed in the lid mold. I will give you.

Next, a foaming material 31 such as a polyurethane material is injected into the skin 20, and the foaming mold 40 is closed as shown in FIGS. As a result, the foam molding space S is formed between the skin 20 and the base material 10, and the skin peripheral edge 22
The sealing surface 12 on the periphery of the base material 10 is sandwiched and sealed by the cavity mold 42 and the lid mold 52, and at the same time, the skin peripheral edge 20.
Is fixed. Further, the foam vent space 14 on the sealing surface of the base material 10 communicates the foam molding space S with the gap 58 on the mold closing surface, and thereby the foam molding space S communicates with the outside of the foam molding die 40.

The foaming raw material 31 in the foam molding space S foams and fills the foam molding space S. At that time, the foaming gas generated from the air in the foam molding space S and the foaming raw material is driven away as the foaming raw material 31 is filled, passes through the gas vent groove 14, and passes through the gap 58 on the mold closing surface to the outside of the foam molding die 40. Escape to. Moreover, since the skin peripheral edge 22 is fixed in close contact with the sealing surface 12 of the base material 10, the vicinity of the skin peripheral edge 22 is unlikely to be deformed by the foaming heat of the foaming raw material, the foaming pressure, or the like. There is almost no danger of the ends being blocked. In particular, when the inner end of the gas vent groove 14 projects into the foam molding space S as in this embodiment, one end of the gas vent groove 22 may be deformed even if the outer peripheral edge 22 is deformed. It is possible to reliably perform degassing without blocking 14a.

By degassing, the foaming raw material 31 fills the foam molding space S without any gaps without being disturbed by the residual air and the foaming gas. Further, since the foaming raw material 31 increases in viscosity and decreases in fluidity as the foaming reaction progresses, there is almost no possibility of leaking from the foam molding space S to the mold closing surface through the narrow gas vent groove 14.

The foaming raw material 31 filling the foam molding space S becomes integral with the skin 20 and the base material 10 due to the adhesive property at the time of foaming, and hardens to become a foam. Thereafter, the foam molding die 40 is opened and the foam molded article 70 shown in FIG. 2 is taken out. The obtained foamed molded product 70 integrally has the skin 20 and the base material 10, and the foamed body 30 formed from the foaming raw material 31 therebetween, and is a good product having no wall thickness or voids. Skin peripheral edge 22 and substrate 10
The peripheral edge is cut off from the position d-d when not needed.

In the above description, the case of the open pouring method in which the foaming raw material is injected with the foaming mold opened and the mold is closed after the pouring, is explained. Can also be applied to a closed injection method in which a foaming raw material is injected with the foaming mold closed.

[0027]

As shown and described above, according to the present invention, it is possible to prevent the foaming raw material from leaking out and prevent the foaming mold from being contaminated during the production of the foaming molded product. The application can be omitted. Moreover, since burrs due to the leaked raw material can be eliminated, it is possible to omit the burr removal work after foam molding. Further, since the foaming mold does not require complicated processing and a conventional foaming mold can be used, it has a very high practical value.

[Brief description of drawings]

FIG. 1 is a sectional perspective view of an embodiment of a base material according to the present invention.

FIG. 2 is a cross-sectional view of a foam-molded product foam-molded using the base material.

FIG. 3 is a cross-sectional view of a foam mold showing foam molding using the base material.

FIG. 4 is a cross-sectional view showing a closed mold state during the foam molding.

5 is a cross-sectional view showing an enlarged main part of FIG.

[Explanation of symbols]

 10 Base Material 12 Sealing Surface 14 Degassing Groove 20 Skin 22 Skin Edge 30 Foam 31 Foaming Raw Material 42 Cavity Mold 52 Lid S S Foam Molding Space

Claims (2)

[Claims] 1. A base material, which is disposed on one side of a skin and forms a foam molding space between the skin and the skin, is provided with a sealing surface at a peripheral edge thereof, the sealing surface being in close contact with the peripheral edge of the skin, and the sealing surface. A base material for a foam-molded article, which is provided with a gas vent groove that communicates the inside and outside of the molding space. 2. A foaming raw material is injected into a skin arranged in a cavity mold, and the foaming raw material is integrally foamed with the base and the skin in a foam molding space between the base arranged in the lid mold and the skin. In the method for producing a foam-molded article, the base material according to claim 1 is arranged as a base material in a lid mold so that a gas vent groove faces a skin peripheral edge of the cavity mold. The method for producing a foamed molded article, wherein the sealing surface and the peripheral edge of the skin are brought into close contact with each other to seal, and the foaming raw material is foamed in a state where the inside and outside of the foamed body molding space are communicated with each other.