JPS6235833A - Manufacture of expansion molded part with skin material - Google Patents

Abstract

PURPOSE:To enable to efficiently perform molding operation without destroying and deforming skin material by a method wherein the surface of the skin mate rial is cooled by being blasted with low-pressure air after the vacuum forming of the skin material and before the pressure feeding and filling of resin. CONSTITUTION:A skin material S, arranged between a male mold 1 and a female mold 2 and softened by heating, is vacuum-formed by being deformed along the surface of the male mold 1 so as to closely contact with the surface by extracting the air through the vacuum vent 10 of the male mold 1 under vacuum. After that, the surface of the skin material is cooled and cured by the low-pressure air, which is introduced through the pressure air leading-in ports 41 of fillers 4 so as tofflow in a cavity 3. As a result, even when pressure air and resin particles collide against the skin material S at the pressure feeding and filling of the resin particles, neither destruction nor deformation of the skin material occur and consequently the molding operation is also performed efficiently.

Description

[Detailed Description of the Invention] Technical Field> The present invention relates to a method for manufacturing a foamed molded product with a skin material, in which a skin material made of a thermoplastic resin sheet or the like is integrally joined along the surface of the foamed molded product. It relates to a method of manufacturing a foam molded product with material.

<Prior Art> Foamed molded products with skin materials as described above are widely used as ceiling materials for automobiles, lining materials for buildings, and the like.

As a method of manufacturing such a foam molded product with a skin material,
First, a heat-softened thermoplastic resin sheet is placed on the front of one of a pair of male and female molds for foam molding, and vacuum suction is applied from the mold side to perform so-called vacuum forming. The mold cavity formed between the molded skin material and the other mold is filled with expandable thermoplastic resin particles, and foam molding is performed to integrate the molded foamed product and the skin material. There is a way to make it happen.

As a specific example of the above method,
This method is disclosed in Japanese Patent Application Laid-open No. 156, Japanese Patent Application Laid-open No. 54-24975, Japanese Patent Application Laid-open No. 73532-1984, and the like.

The above prior art method uses 1! as a mold! Only a pair of molds for foam molding is used, there is no need to prepare a separate mold for vacuum molding, and the manufacturing equipment is simplified. At the same time, vacuum molding and foam molding are performed continuously. This method has good manufacturing efficiency and excellent integrity between the skin material and the foamed molded product.

However, in the above method, after vacuum forming the skin material,
When filling expandable thermoplastic resin particles between the skin material and the other mold, the resin particles are pumped and filled into the mold cavity with pressurized air using a filler attached to the mold. However, this pressurized air and resin particles are blown and collided with the skin material of the vacuum forming center, which is still in a heated and softened state, at a considerably high velocity, so that the inner surface of the skin material may be destroyed or ” or deformation problems were occurring.

In order to solve the above problem, for example, if you lower the air pressure during filling to reduce the pressure or impact force on the skin material, it will take time to fill the resin particles, reducing work efficiency and molding. This is not preferred in practice because the resin particles cannot be completely filled into the cavities, resulting in incomplete filling.

Also, leave it for a while until the skin material is completely cured.
If the filling of resin particles is delayed, there will be a lot of wasted work time.
There is a problem in that the overall work efficiency is reduced.

Therefore, the purpose of this invention is to solve the problems of the prior art described above, and to produce a foam molded product with a skin material that can be worked efficiently without destroying or deforming the skin material. The goal is to develop methods.

<Structure> In order to achieve the above-mentioned objective 1, a heat-softened skin material is placed between a pair of molds made of fibers,
After the skin material is molded along one mold by vacuum suction from one mold, foaming heat is applied together with pressurized air into the mold cavity formed between the skin material and the other mold. In a method of manufacturing a foam molded product with a skin material by pressure-feeding and filling plastic resin particles and performing foam molding, after vacuum-forming the skin material and before pressure-filling the resin particles, low-pressure air is applied to the surface of the skin material. It is characterized by spraying and cooling the surface of the skin material.

<Example> Next, an example of the present invention will be described below with reference to the drawings.

FIG. 1 shows the entire molding apparatus used to carry out the present invention, and a pair of male and female molds (1) and (2) are basically similar to molds for ordinary foam molding. It has a male type (1) and a female type (a) that can be opened and closed with each other.
A foamed molded product can be manufactured by filling a mold cavity (3) formed between the mold cavity (3) with foamable thermoplastic resin particles from a filling device (4) and heating and melting the resin particles.

As shown in detail in FIG. 2, the filling device (4) includes a resin particle supply port (40) and a pressure air introduction port (41).
) and a filling port (42) for resin particles.
6), it is connected to a supply source of pressurized air. Also,
The filling port (42) passes through the old mold (2) and opens into the mold cavity (3) on the inner surface of the mold. Furthermore, the female mold (2) is provided with a core vent (20) for a steam hole.

However, in the case of this invention, in order to vacuum form the skin material (S), the skin material (S) is placed between the male mold (1) and the old mold (2).
The male mold (1) is provided with a vacuum suction hole (10), and the male mold (1) is equipped with a vacuum suction hole (10).
Vacuum suction can be applied to the surface of the male mold (1) through a vacuum suction hole (10) from a vacuum suction pipe (11) attached to the male mold (1). Note that no steam holes such as core vents are formed in the male mold (1).

The pressure introducing vibrator (40) of the filling device (4) is connected to the control device (60) of the air pressure horn, so that the pressure or the air flow rate can be adjusted.

A method of using the above-mentioned molding apparatus will be explained step by step.

First, as a skin material (S), if it is a sheet 1-shaped body that can be molded into a lζ shape along the surface of the male mold (1), it is made of 8 scales of thermoplastic resin. A foamed sheet or a non-foamed sheet, stretchable paper, cloth, nonwoven fabric, etc. can be used, and a laminated sheet formed by layering a plurality of the above-mentioned sheet materials can also be used. Further, even if the sheet material is difficult to mold by itself, it may be possible to use it by laminating it on the above-described moldable sheet material.

After placing the above skin material (S) in the center of the opened male mold (1) and female mold ('2J), the molds are clamped and the male mold (
This skin material (S) is brought into contact with the surface of 1), but this skin material (S) must be heated in advance to a softened state that can be vacuum-formed, or
After placing it between 1) and the female mold [2), heat it from the surroundings to soften it.

In this state, when vacuum suction is applied from the vacuum suction hole (10) of the male mold (1), the skin material (S) is brought into close contact along the surface of the male mold (1), as shown in Figure 1. This results in what is called vacuum forming.

After that, using the conventional method, as shown in Figure 3,
With the pair of molds, i.e., the male mold (1) and the female mold (a) slightly opened and the cranking (1) removed, resin particles are immediately pumped and filled, but in the case of this invention method, , second
As shown in the figure, the pressure air inlet (41) of the filling device (4)
), low-pressure air adjusted to a constant low pressure is introduced by the control device (60), and is caused to flow into the mold cavity (3). J3, at this stage, the supply port (
The hopper connected to 40) is closed to prevent resin particles from being fed into it.

Then, the low-pressure air that flowed into the mold cavity (3) spreads through the skin material (
It spreads and flows throughout the surface of the female type (
It is discharged from the steam hole (20) of 2) and the gap between the GT mold (1) and the female mold (2), but as it flows through the mold cavity (3), it touches the surface of the skin material (S). It will be air cooled.

Note that the pressure of this low-pressure air is such that the air flow velocity is such that it efficiently removes heat from the skin material (S), and
The air blown onto the skin material (S) causes the skin material (S) to
The pressure must be low enough not to cause any damage. For example, the diameter of the air inlet (41) of the filling device (4) is 3.5
In the case of n+mφ, the original pressure may be set to about 0.5 kg4.

In addition, the above air cooling time is set so that the skin material (S) is cooled and hardened to the extent that it will not be broken or deformed even if it is sprayed with pressurized air or resin particles in the resin particle filling process described later. This is sufficient, and there is no need to completely cool it to room temperature. For example, under the above pressure conditions, cooling for about 7 seconds is sufficient.

After the skin material (S) is cooled as described above, the third
As shown in the figure, when relatively high-pressure air, which is necessary for filling normal resin particles, is introduced into the pressure air inlet (41) and at the same time the resin particle storage hopper is opened, the resin particles (B ) is forced into the mold cavity (3) through the supply port (40) of the filling device (4) and from the filling port (42) together with pressurized air. The air pressure for this pressure filling may be the same as that for normal foam molding, and is carried out, for example, at about 5 kgJ culm.

After that, the cranking gap (1) is closed and steam heating is performed, followed by a heating process and a cooling process.The subsequent processes are performed in exactly the same way as the conventional molding method, so detailed explanations will be omitted. .

° Among the methods of this invention explained above, the mold +11
(2), the filling device (4), etc., may be similar to those used in conventional manufacturing equipment for foam molded products with skin materials, and are not limited to the structures shown in the drawings.

In order to blow low-pressure air to cool the skin material (S), if the air inlet (41) of the filling device (4) is used, the conventional device can be conveniently used without any modification. However, a mechanism for blowing low-pressure air into the mold cavity (3) may be provided separately from the filling device (4).

Next, regarding the materials of the skin material (S) and resin particles (B), the same materials as those used in conventional foam molded products with skin materials can be used. A sheet-like body can be used, and as the resin particles (B), expandable thermoplastic resin particles consisting of a single or copolymer of various thermoplastic resins such as polystyrene, polyethylene, polypropylene, or a mixed resin can be used.

The foamed molded product with a skin material produced by the method of this invention can be freely applied to automobile ceiling materials, architectural lining materials, and other products, but especially the finish of the skin material (S) exposed on the surface. It is suitable for applications that require better quality than conventional products.

Effect> According to the method of the present invention configured as described above, the heat-softened skin material (S) is placed in one of the molds, for example, the male mold (
After vacuum forming along 1), a mold cavity (3) is formed between the skin material (S) and the other mold, for example, the female mold (2).
Before filling the resin particles under pressure, low-pressure air is blown onto the surface of the skin material (S) to cool the surface of the skin material fs). I
vJ! Therefore, even if pressurized air and resin particles collide with the skin material (S) during pressure-feeding and filling of resin particles, the skin material (S) will not be destroyed or deformed, and the skin material produced after foam molding will be The finish of the foam molded product with material is good, and the outer surface of the skin material (S) is smooth and free from scratches and distortions.

In particular, the air that is blown to cool the skin material (S) has a lower pressure than the air pressure used when filling the resin particles under pressure, so there is no fear of damaging the skin material (S).

Moreover, the time required to cool the skin material (S) is sufficient if the skin material (S) in a heat-softened state is not destroyed by filling air, etc., so it is sufficient to cool the skin material (S) in a relatively short period of time. However, it is sufficiently effective, and during the transition from the vacuum forming process to the foam forming process, the skin material (S) is cooled.
If this is done, it will reduce the efficiency of the manufacturing process and complicate the work.In addition, air for cooling is introduced into the air inlet (41) of the filling device (4). Since it uses air, there is no need to install special equipment.
Equipment costs and operating costs are low, making it an extremely economical method.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, in which Fig. 1 is a schematic diagram of the overall structure, Fig. 2 is an enlarged sectional view of the main part at d3 in the cooling process, and Fig. 3 is an enlarged main part at d3 in the filling process. FIG. (1) (21...Mold, (3)...
・Mold cavity, (4)... Filler, (6)...
・Air piping, (S)...Skin material, (B)...
...resin particles.

Claims (1)

[Claims] 1. Heat and soften between a pair of male and female molds. Place the skin material and remove it from one mold. Apply dry suction to move the skin material along one mold. After molding, the skin material and the other mold Pressurized air is placed in the mold cavity formed between At the same time, expandable thermoplastic resin particles are pumped and filled. foam molding with a skin material. In the method of manufacturing shaped products, the skin material is After vacuum forming, resin particles are pumped and filled. Blow low-pressure air onto the surface of the skin material before and cool the surface of the skin material. Manufacture of foam molded products with skin material characterized by Method.