JPH0443767B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for molding interior materials for automobiles.

<<Prior art and its problems>> FIG. 2A shows an interior material installed in the trunk of an automobile, and this type of interior material has a skin material 22 on the surface of a core material 21, as shown in FIG. 2B. A cushioning material 23 is formed on the back surface of each of the two, and is formed into a predetermined molded product shape by press molding.

The core material 21 is made of a composite resin sheet, such as a sheet made by mixing wood powder with polypropylene resin, and the thickness thereof does not change much before and after press molding.

For the skin material 22, carpet, nonwoven fabric, or the like can be used depending on the purpose of the interior material.

The cushioning material 23 is made of sound-absorbing material such as urethane foam or felt.

Conventionally, such interior materials are shown in Fig. 3 A, B, and C.
It is formed through the steps shown below.

That is, the core material 21 is formed into a predetermined surface shape by press molding, the skin material 22 is integrally formed on the surface thereof, and at the same time, it is trimmed to a predetermined outer peripheral shape, and then the mold is demolded (Fig. 3). A).

Next, as shown in FIG. 3B, a hot melt adhesive 31 is applied to the back surface of the core material 21.

Thereafter, the cushioning material 23 trimmed to a predetermined outer peripheral shape is attached to the back surface of the core material 21, and in this state it is set in a mold (not shown), and the upper and lower molds are engaged and pressed together to remove the mold.

Then, as shown in FIG. 3C, the cushioning material 23 is pressed onto the entire back surface of the core material 21 while following the shape of the back surface.

However, such conventional molding methods not only involve a large number of steps and are complicated, but also increase equipment costs and material costs for adhesive application.

In addition, the cushioning material 23 is joined to the core material 21 by press crimping, but when adjusting and setting the clearance between the upper and lower molds on the horizontal plane on the mold surface,
If the clearance on the horizontal plane is set smaller than the specified value, the thickness of the core material will not be reduced or deformed by compression and will remain approximately constant, so the clearance between the upper and lower molds will be smaller than the specified value. Horizontal surfaces and inclined surfaces: Vertical surfaces are different, and the clearance on inclined surfaces may be narrower than that on horizontal surfaces. In other words, the thickness of the cushioning material becomes thinner on the sloped surface of the cushioning material after being crimped, and cracks may occur during molding.

<Object of the Invention> The object of the present invention is to provide a molding method that can be easily molded with a small number of steps and that does not cause cracks in the cushioning material.

<Structure and Effects of the Invention> In order to achieve the above object, the present invention has a curved surface formed by forming a skin material on the surface of the core material and a cushioning material having an anchoring effect on the joint surface on the back surface. In the method for molding an automobile interior material, the core material is a foamable composite resin sheet of a required thickness made of a sheet-like extruded product containing a foaming agent, and a cold press lower mold having a required curved surface shape is used. The cushioning material, the foamable composite resin sheet which has been softened by heating in advance, and the skin material are laminated in this order on the mold surface, and then the cold press upper mold is engaged and pressed with the lower mold, The above foamable composite resin sheet is compressed and flattened to a nearly uniform thickness, a core material with rigidity is formed into the desired curved shape, and a cushioning material is attached by anchor bonding along the curved shape of the back surface of this core material. It is characterized by being integrated.

According to this configuration, the skin material and the cushioning material can be integrally bonded to the core material in one step, and can be trimmed during demolding, so that a molded product having a desired curved surface shape can be obtained in approximately one step. In other words, the number of steps is significantly reduced.

In addition, when a foamable composite resin sheet is heated and softened, it becomes expanded, but when the foamed composite resin sheet in this expanded state is sandwiched between a skin material and a cushioning material and cold press compressed, the foamable composite resin sheet is cooled. Compressive deformation occurs as it hardens.

During this compressive deformation of the foamable composite resin sheet, the skin material and the cushioning material are joined to the foamable composite resin sheet, but at this time, the thickness of the cushioning material on the inclined and vertical surfaces does not become thinner. The conventional problem of cracks occurring during molding is eliminated.

Furthermore, on the front and back sides of the foamable composite resin sheet,
The skin material and cushioning material are located, and the foamable composite resin sheet has excellent heat storage properties during cold press molding.
Since good fluidity of the resin is obtained, there is an effect that moldability is improved, and there is also an effect that the cushioning material is firmly bonded to the foamable composite resin sheet due to the anchor effect.

<<Description of Examples>> FIG. 1 shows a method for molding an interior material according to an example of the present invention.

This interior material molding method uses a foamable composite resin sheet 1 of a desired thickness made of a sheet-like extrusion molded product containing a foaming agent as a core material, and a mold surface of a cold press lower mold 2 having a desired curved surface shape. A cushioning material 3, a foamable composite resin sheet 1 which has been preheated and softened, and a skin material 4 are laminated on top in this order, and then a cold press upper mold 5 is engaged and pressed with the lower mold 2 to form a foam. After the composite resin sheet 1 has cooled, the portion protruding from the outer periphery of the mold is trimmed along the outer periphery of the mold and removed from the mold, whereby an interior material having a predetermined product shape as illustrated in FIG. 2 can be obtained.

The mold surfaces of the cold press lower mold 2 and upper mold 5 are formed to have a predetermined surface shape of a molded product.

The cushioning material 3 and the skin material 4 are made of the same materials as conventional ones, and in this embodiment, the cushioning material 3 is made of urethane foam, and the skin material 4 is made of nonwoven fabric.

The foamable composite resin sheet 1 is based on polypropylene mixed with wood flour, mixed with an appropriate amount of azohexahydrobenzonitrile as a foaming agent, and a small amount of an initiator and other additives, kneaded, and then adjusted to the foaming start temperature. The following is extruded into a sheet.

When this foamable composite resin sheet 11 is put into an infrared heater device and heated, it becomes plasticized and the temperature of the foaming agent contained therein is raised to a temperature higher than its foaming start temperature, thereby causing the foamable composite resin sheet 1 expands in the thickness direction. For example, board thickness 1.4mm
The foamable composite resin sheet 1 is expanded to a thickness of 2.3 mm.

The foamed composite resin sheet 1 in this expanded state is placed on the cushioning material 3, the skin material 4 is placed on the foamed composite resin sheet 1, and the upper mold 5 is engaged with the lower mold 2.・Tighten.

Then, the foamable composite resin sheet 1 is compressed and deformed along the shape of the mold surface. That is, as the foamable composite resin sheet 1 is compressed and deformed, the skin material 4 and the cushioning material 3 are pressed onto the front and back surfaces of the foamable composite resin sheet 1.

During this compressive deformation process, the foamable composite resin sheet 1 shrinks, for example, from the above-mentioned thickness of 2.3 mm to about 1.4 mm. Therefore, the wall thickness of the cushioning material 3 does not become extremely thin in the uneven parts formed by the inclined and vertical surfaces of the mold surface, and cracks do not occur during molding. Composite resin sheet 1
Since it is joined in an anchoring manner, good crimping can be achieved.

Note that when the cushioning material 3 is demolded, it is restored and returns to its original thickness.

[Brief explanation of drawings]

Fig. 1 is an explanatory cross-sectional view showing a method of molding an interior material according to an embodiment of the present invention, Fig. 2 shows the trunk room side as an interior material, Fig. A is a schematic perspective view, and Fig. B is a - line. Cross-sectional view, Figure 3 A, B,
C is a cross-sectional explanatory view showing a conventional molding process of an interior material. 1...Core material, 2...Lower mold, 3...Buffer material, 4...Skin material, 5...Upper mold.

Claims (1)

[Scope of Claims] 1. A method for forming an interior material for an automobile having a curved shape formed by forming a skin material on the surface of the core material and a cushioning material having an anchoring effect on the joint surface on the back surface of the core material, comprising: A foamable composite resin sheet of the required thickness made of a sheet-like extrusion molded product containing a foaming agent is used as the material, and a cushioning material and preheated material are placed on the mold surface of a cold press lower mold with the required curved surface shape. The foamable composite resin sheet and the skin material, which have been softened by the process, are laminated in this order, and then the cold press upper mold is engaged and pressed with the lower mold to compress the foamable composite resin sheet to a substantially uniform thickness. An automobile interior characterized by forming a flattened and rigid core material into a required curved shape, and integrally attaching a cushioning material along the curved shape of the back surface of the core material by anchor bonding. How to form the material.