JPH044129A - Forming method of composite layer joint molded product for which hot expandable foam is used - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to the formation of a composite layer bonded molded article (hereinafter simply referred to as a molded article) using a heat-expandable foam body (hereinafter simply referred to as a foam body). The present invention relates to a method, and particularly to a method for forming a molded product suitable for use as an automobile interior part such as a door trim.

[Prior art] Conventionally, a manufacturing method for molded products for automobile interior parts such as door trims that can make the thickness of bonded composite layers uniform is disclosed in Japanese Patent Application Laid-open No. 6
A technique disclosed in Japanese Patent No. 3-87312 and the like is known. The molded products disclosed in the above-mentioned publications and the like are generally manufactured through the following steps.

That is, as shown in FIG. 7, PVC resin (polyvinyl chloride) powder is attached to the mold surface of a slush molding mold 21 and heated to form a skin 22 along the mold 21. PVC resin powder mixed with a foaming agent is attached to the top, and a heater 23 is attached as shown in FIG.
The foam is foamed to form a foam layer 24 and a skin-covered foam layer 25 is obtained.

On the other hand, as shown in FIG. 9, a core material layer 26 made of polypropylene resin, wood powder filler, etc. is laminated with a hot melt adhesive 27 on one side, and after being heated and softened, the laminated adhesive 27 is applied to the other side. Cushion layers 28 made of non-woven fabric or the like having a constant thickness are stacked and molded using a lower press mold 10 and an upper press mold 11 to form a cushion layer 29 with a core material layer. After that, as shown in FIG.
On top is a skinned foam 25 with the foam layer 24 facing upward.
A cushion layer 29 with a core material layer with the cushion layer 28 facing downward is placed on the press upper mold 11, and after applying an adhesive 32 to the surface of the foam layer 24, both molds are pressed to form a skin. Foam layer 25 and cushion layer 2 with core material layer
9 are bonded and integrated to obtain a molded product 30 of a predetermined shape (see FIG. 11).

[Problems to be Solved by the Invention] However, the molded product 30 produced by the conventional manufacturing method described above,
By joining the foam layer 24 to the cushion layer 28,
The voids caused by the residual gas during the formation of the foam layer and the variations in the thickness of the foam are absorbed, resulting in good thickness uniformity, but as shown in FIG. Therefore, in places where the thickness of the foam layer 24 is highly uneven, especially in places where the thickness is uneven such as the corner part 30A, it is not possible to absorb the variation in wall thickness, and the foam layer 24 and the cushion layer 28 are There was a problem in that a gap 31 was formed between the two, resulting in a defective bonding area and deteriorating quality.

Therefore, the object of the present invention is to solve the above-mentioned problems in the conventional manufacturing method, and to achieve good uniformity in board thickness, and to ensure that the cushion layer and the foam layer are in close contact even in corner areas, etc. It is an object of the present invention to provide a method for forming a molded article that can improve the quality of the product by improving the adhesion between the cushion layer and the foam layer.

[Means for Solving the Problems] The means of the present invention for solving the above-mentioned problems is to prepare a foam layer with a skin of a predetermined shape in which a foam layer is molded and bonded on the back side of the skin, and to mold the foam layer into upper and lower molds. On one side of the press mold,
While the foam layer is arranged facing outward, a foam body with a core material layer is prepared by adhering a foam body to serve as a cushion layer along the inner surface of the core material layer formed into a predetermined shape,
This is placed in the other press die with the foam body facing outward, and the foam body is heated and an adhesive is interposed between the two presses so that the foam layer with skin and the foam body with core material layer overlap. After the mold is crimped, the foam body is expanded to form a cushion layer and is bonded to the foam layer.

The foam contains a foaming agent and has a constant layer thickness, and has the property of foaming and expanding when heated, and solidifying after foaming to form a porous cushion layer.

[Function] In the press-type crimping process, the foam expands along the surface of the foam layer. The expanded foam body adheres to the surface of the foam layer. The expanded foam solidifies and becomes a cushion layer.

Embodiment Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 6.

First, PVC resin is foamed on the back side of a skin 1 such as a synthetic resin sheet to form a foam layer 2 and molded into a predetermined shape, and as shown in FIG. A foam layer 3 is formed. Note that slush molding or the like is used to form the skinned foam layer 3.

Further, a core material layer 4 having a predetermined shape is formed by preforming. The core material layer 4 of this example is mainly composed of polypropylene resin and wood powder filler. A foam body 5 of a certain thickness that expands when heated, such as a polyurethane layer containing a foaming agent, is adhered to the back surface of the molded core material layer 4 with an adhesive, and a hot melt adhesive is attached to the outer surface of the foam body 5. A foam body 7 with a core material layer shown in FIG. 6 is obtained by bonding with a film-like adhesive 6 of the same type. Note that the adhesive 6 may be a Botmelt type adhesive and may be spray applied.

Thus, the skinned foam layer 3 with the foam layer 2 facing upward is disposed on the mold surface of the lower press mold 10 (see FIG. 2), while the mold surface of the upper press mold 11 (see FIG. 1) A foam body 7 with a core material layer is placed on the surface with the adhesive 6 facing downward (see FIG. 1). Thereafter, as shown in FIG. 1, a heater 12 is placed below the foam body 7 with a core material layer placed on the press upper die 11 to melt the adhesive 6 of the foam body 7 with a core material layer. The foam body 5 is heated.

The adhesive 6 melts due to heating, and the foam body 5 begins to expand. Immediately before the foam body 5 starts to expand, as shown in FIG. Stack and press. In this pressing process, the foam body 5 expands and adheres closely to the bonding surface of the foam layer 2. After the press upper mold 11 and the press lower mold IO are pressed together, the molds are removed to obtain a predetermined molded product 8 (see FIG. 4).

In the obtained molded product 8, the cushion layer 5A based on the expanded foam body 5 and the foam layer 2 were adhered with the adhesive 6, and the molded product 8 had a constant thickness and a good finish.

The molded product 8 was cut to examine the bonding state between the cushion layer 5A and the foam layer 2 at the corner part 8A, and the cushion layer 5A was in close contact with the foam layer 2 without any gaps, and the adhesiveness was strong. Therefore, the cushioning properties of the cushion layer 5A were also sufficient. The molded product 8 of this example is applied to automobile interior parts such as door trims.

[Effects of the Invention] In the present invention, the foam layer with a skin layer and the foam layer with a core material layer are pressed together so that they overlap, and then the foam body is expanded, so that the foam layer has a foam layer. It expands to follow variations in the body's wall thickness, and forms a cushion layer by tightly clumping together with the foam layer without leaving any gaps.

Furthermore, in the present invention, when pressing the foam layer with a skin and the foam body with a core material, an adhesive is interposed, so that the cushion layer is bonded to the foam layer, resulting in a molded product with a constant thickness and good quality. be able to.

[Brief explanation of the drawing]

1 to 6 show examples of the present invention, and FIG. 1 is a heating process diagram of a foam body with a core material layer placed on a press upper die;
Figure 2 is a diagram of the process before crimping of the upper press die and lower press die, and Figure 3
The figure shows the state of crimping between the upper press mold and the lower press mold, Figure 4 is an enlarged view of the main parts of the molded product, Figure 5 is a cross-sectional view of the foam layer with skin, and Figure 6 is the foam body with core material layer. FIG. Figures 7 to 11 show the conventional manufacturing method, Figure 7 is a process diagram of forming the skin by slush molding, Figure 8 is a process diagram of forming the foam layer, and Figure 9 is a diagram of the bonding of the core layer and cushion layer. and forming process drawings, Figure 1θ is a process drawing before forming by press, 1st
Figure 1 is an enlarged sectional view of the main part of a conventional molded product. 1... Skin 2... Foam layer 3... Foam layer with skin 4... Core material layer 5... Foam body 5A... Cushion layer 7... Foam with core material layer Body 8...Molded product IO...Press lower mold 11...Press upper mold

Claims (1)

[Claims] A foam layer with a skin of a predetermined shape is prepared by molding and bonding a foam layer on the back side of the skin, and this is placed on one side of a press mold consisting of an upper and lower mold with the foam layer facing outward. A foam body with a core material layer is prepared by adhering a heat-expandable foam body to serve as a cushion layer along the inner surface of the core material layer molded in placing it facing outward, heating the heat-expandable foam body and interposing an adhesive;
A heating method characterized by pressing both press molds so that the foam layer with skin and the foam layer with core layer overlap, and then expanding the heat-expandable foam to form a cushion layer and bonding it to the foam layer. A method for forming a composite layer bonded molded product using an expandable foam body.