JPH06179224A - Production of resin foam molded piece - Google Patents

Abstract

PURPOSE:To provide a resin foam molded piece production method in which a defective quality, such as a sinkage caused by a foaming gas or the like, can be easily prevented from occurring. CONSTITUTION:A skin material 3 is disposed on an inner wall surface of a lower mold 12 in a mold 1. A core 2 is disposed in the lower mold 12. Thereafter, a foamable resin material is injected and thermally foamed to be molded into a resin foam molded piece. In this production method, vent holes 41, 42 are respectively provided in undercut parts 31, 32 of the skin material 3 at least one in each. In addition, the vent holes 41, 42 provided in the undercut parts 31, 32 cannot be seen from outside when the resin foam molded piece is installed.

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 resin foam molded article capable of easily preventing quality defects such as a state of wall thinning due to air present in a molding die, foaming gas generated from a foamed resin raw material, and the like. .

[0002]

2. Description of the Related Art For example, a resin foam molding used as an armrest for an automobile interior (hereinafter referred to as "armrest") and the like is made of a synthetic resin such as soft vinyl chloride, and is used as a skin material constituting an outer skin of the product. The core material is provided inside or on the back side of the product for the purpose of reinforcement and the like, and a foam layer constituting a base material portion of the product. Then, this molded product is obtained by inserting a skin material molded into a predetermined shape (sheet shape, bag shape, etc.) by rotational molding into the inner wall portion of the molding die, and then forming a cavity in the molding die. After arranging the core material in the core and injecting the foaming resin raw material, the foaming resin raw material is heated and foamed (Japanese Patent Laid-Open No. Sho 6-66).
See JP-A-3-109018, JP-A-63-120609, etc.).

[0003]

However, the resin foam molding 6 for armrests shown in FIG. 2 is formed on the inner wall surface of the lower mold of the molding die 12a as shown in FIG. When the material 3a is arranged and manufactured, the gas B is likely to accumulate in the undercut portion 31a that constitutes the end or the like of the skin material. This is because a non-breathable resin such as soft vinyl chloride is generally used as the skin material 3a of the resin foam-molded product, so that air and foamed resin existing in the molding die from the periphery of the undercut portion 31a. This is because the foaming gas or the like generated from the raw material (hereinafter referred to as "foaming gas or the like") cannot escape to the outside of the cab. Then, the foaming gas and the like concentrate around the undercut portion and cause quality defects such as a state of lack of thickness in the final product.

The present invention has been made in order to solve the above problems, and is a method for producing a resin foam-molded article capable of easily preventing quality defects such as a state of wall thinning due to foaming gas accumulated in an undercut portion. The purpose is to provide.

[0005]

In order to achieve the above object, the structural feature of the invention according to claim 1 is that a skin material is arranged on the inner wall surface of a lower mold in a molding die, and After the core material is placed in the mold, the foamed resin raw material is injected, and in the method for producing a resin foam molded article formed by heating and foaming the foamed resin raw material, at least one gas is provided in the undercut portion of the skin material. That is, a hole is provided. Further, the structural feature of the invention according to claim 2 is that the gas vent hole is provided in the undercut portion which is not visible from the outside when the resin foam molded article is attached.

[0006]

In the invention according to claim 1 configured as described above, at least one gas vent hole is provided in the undercut portion of the skin material. As a result, the foaming gas or the like is smoothly discharged from the hole continuing from the inside of the cavity of the mold to the outside of the skin. Therefore, even in the vicinity of the undercut portion where foaming gas or the like tends to stay, the foaming gas or the like passes through as it is and is discharged to the outside of the epidermis. Also,
In the manufacturing method of the present invention, the undercut portion of the skin material,
Since it is sufficient to form the gas vent hole, it is possible to easily and effectively maintain and improve the quality of the final product.
Further, in the invention according to claim 2 configured as described above, the gas vent hole is provided in the undercut portion which is invisible from the outside when the resin foam molded article is attached. As a result, at the stage of using the resin foam-molded product, the gas vent hole is hidden by the invisible part and does not appear on the surface as the appearance of the interior parts or the like.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view showing a molding step of a resin foam molded product (hereinafter referred to as “molded product”) 6 for armrests shown in FIG. The figure shows a molding die 1, a reinforcing core material 2 arranged in the die, a skin material 3, and a urethane foam layer (base material layer) 5 formed in the die. As shown in FIG. 1, the mold 1 comprises an upper mold 11 and a lower mold 12, and the portion shown in FIG. 1 corresponds to the AA cross section of the final molded product of FIG. .

First, the molding die 1 is opened and the lower die 1
The skin material 3 is closely arranged so as to be along the inner wall of 2. This skin material 3 is a bag-shaped body made of soft vinyl chloride resin obtained by rotational molding, and is installed in the lower mold 12 so that the opening thereof opens upward. The surface including the opening is bent from the visible portion so as to form a mounting surface, and forms undercut portions 31 and 32 during foam molding. Therefore, a plurality of gas vent holes 41 and 42 penetrating the inside and outside of the skin are provided at predetermined intervals in the longitudinal direction of the mounting surface surrounding the opening. Here, the hole diameters of these gas vent holes 41 and 42 are
It is preferably within the range of 1 to 2.5 mmφ. This means that when the hole diameter is small, less than 1 mmφ,
At the same time when the gas escapes from the hole, the foaming raw material becomes in a state of blocking the hole, so that the gas cannot be released thereafter. On the other hand, if the hole diameter is larger than 2.5 mmφ, the hole 4
Since the foaming raw material that has entered the insides of 1 and 42 causes a large burr on the surface of the final molded product, it causes a molding defect, or causes a defect such as an extra step for removing the burr. Is. Even if the hole diameter is within the above range, a thin burr is generated from the gas vent hole, but the burr is similar to the burr generated when the conventional hole is not opened, which is within the allowable range. The number of gas vent holes formed in each of the undercut portions can be changed as necessary (according to the amount of gas or the like generated).

Next, as shown in FIG. 1, the core material 2 was placed at a predetermined position in the molding die 1. The core material 2 is made of polypropylene or metal, but is not limited thereto. Thereafter, raw material urethane was injected into the molding die 6, the upper mold 11 was closed, and foam molding was performed to form the urethane foam layer 5. The above-mentioned raw material urethane may be injected from a raw material injection port or the like which penetrates the molding die 1 and reaches the inside of the cavity after the upper mold 11 is closed. Next, after cooling, the molded product 6 was taken out from the molding die 1. During the foam molding, the foaming gas or the like in the molding die 1 is accurately discharged to the outside of the skin material 3 through the gas vent hole formed in the skin material 3, and the undercut portion 31 of the skin material 3 is discharged. The foaming gas and the like do not stay around 32. For this reason, there was no state of wall thickness throughout this molded product 6, and a resin foam molded product having a good shape was obtained.

In the molded product 6 of this embodiment, the gas vent holes 41 and 42 are formed in the mounting surface of the molded product. Therefore, when the vehicle armrest 6 is used (when it is attached to a vehicle door or the like), the gas vent hole is completely hidden by the invisible portion, and the appearance of the final product is not damaged.
The undercut portion referred to in the present invention is not limited to the end portions 31 and 32 of the skin material 3 shown in FIG. 1, but may be a skin portion covering a protruding portion of a resin foam molded product, or a portion where foaming gas is easily retained. It is meant to include broadly.

[0011]

As described above, according to the manufacturing method of the present invention, since there is no formation of a thinned portion around the undercut portion of the skin material of the foamed resin molded product, the quality of the final molded product is improved. Can be maintained. Further, by forming the gas vent hole on the mounting surface of the resin foam molded article, the hole is not recognized from the outside, so that the appearance of the final product during use is not impaired.

[Brief description of drawings]

FIG. 1 is an explanatory vertical sectional view showing a production state of a resin foam-molded article according to this example.

FIG. 2 is a perspective view showing an outer shape of a foamed resin molded product used for an automobile armrest.

FIG. 3 is an explanatory vertical sectional view showing a manufacturing state of a resin foam molded article according to a conventional example.

[Explanation of symbols]

1; Mold, 11; Upper mold, 12; Lower mold, 2; Core material, 3;
Skin material, 31, 32; Undercut portion, 41, 42;
Gas vent holes, 5: urethane foam layer (base material), 6: foamed resin molded product used for automobile armrests, B: foamed gas and the like.

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Claims (2)

[Claims] 1. A skin material is placed on the inner wall surface of a lower mold in a molding die, a core material is placed in the lower mold, and then a foaming resin raw material is injected to heat and foam the foaming resin raw material. A method for producing a resin foam molded article, comprising: forming at least one gas vent hole in the undercut portion of the skin material. 2. The method for producing a resin foam molded article according to claim 1, wherein the gas vent hole is provided in the undercut portion which is not visible from the outside when the resin foam molded article is attached.