JPS581672B2 - Molding method for multilayer molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for molding multilayer molded products in the same mold.

Vehicle interior parts such as insulator dashes, floor insulators, and insulator seat backs are
The skin layer is made of a sound insulating material, and a sound absorbing material is attached to the back surface of the skin layer in order to cut down noise such as engine noise.

To manufacture each of these molded products, a thermoplastic sheet is used as a sound insulating material, this thermoplastic sheet is fixed in a mold, and is formed into the external shape of the molded product by heat compression molding. A sound-absorbing material such as felt was pasted on the back side.

However, in such a method, the felt lining work is troublesome, so recently a method has been proposed in which two layers of foamed resin are molded instead of the felt.

One method is to set the above semi-finished product in the lower mold of a foam molding machine, match the upper mold in this state, and inject and harden foamed resin into the cavity formed between the two molds to integrate the two. However, this molding method requires two molding devices and molds to produce one molded product, and the semi-finished product must be demolded from the mold before being transferred to the next process. Since it is set in a mold, there are drawbacks such as mold misalignment and foaming resin leaking from the gap.

On the other hand, the skin layer is molded by injection molding method etc.
A method has also been proposed in which the lower mold to which the molded body is attached is removed from the molding machine, or the upper mold is converted, thereby allowing the lower mold to be used as a lower mold for foam molding.

However, even with this method, the mold must be removed from the equipment and set again each time molding is performed, and this transfer work is extremely complicated and time-consuming, resulting in warping and deteriorating work efficiency. The operating rate of the device per cycle decreases.

The present invention has been made in view of the above background, and uses a pair of molds whose cavity thickness is variable by adjusting the pinch-off part as a guide so that they can approach and separate. Molding of multilayer molded products that can be used to mold multilayer molded products using equipment, thereby shortening and streamlining the manufacturing man-hours, reducing mold production costs, and reducing the installation space for molding equipment. The present invention provides a method.

An embodiment of the present invention will be described in detail below with reference to the drawings.

Figure 1 schematically shows a molding machine in which the present invention is applied to two-layer molding of an insulator dash. A mold 1 and an upper mold 2 are provided,
A pinch-off part 3, which also serves as an upper and lower guide for the upper mold 2, is erected on the edge of the lower mold 1, and the edge of the upper mold 2 runs along the inner wall of the pinch-off part 3 in order to engage with the inner wall of the pinch-off part 3. The parting surfaces 4 of both molds 1 and 2 are aligned to form a first cavity 5 corresponding to the thickness of the skin layer of the molded product.

Further, by raising the upper mold 2 by a desired distance, a second mold, which will be described later, which is wider than the interval between the cavities 3, is formed.
In order to form a cavity, the height of the pinch-off portion 3 is made sufficiently higher than the amount of overlap of the parting surface 4 of each of the dies 1 and 2.

An ejector bottle 6 is inserted through the center of the lower mold 1 to extrude the molded product after molding, and communicates with the parting surface 4 of the lower mold 1 and the first cavity 5. An introduction groove 7 for the reactive resin liquid is carved on the inner surface.

On the other hand, an injection hole 8 for the foamable resin liquid is formed in the center of the upper mold 2, and an ejector pin 9 is inserted through the both sides of the injection hole 8 to form a skin layer, which will be described later. After molding, the molded body is pressed into the lower mold 1.

10 is a resin injection head communicating with the introduction groove 7;
1 is a resin injection head that communicates with the injection hole 8 .

Next, FIG.
The procedure will be explained step by step using FIG.

First, FIG. 1 shows a state in which the molds 1 and 2 are in the preparation stage for molding, a mold release agent is applied to both molds 1 and 2, and a first cavity 5 is formed by aligning their parting surfaces 4.

If the resin liquid is injected from the resin injection head 10 at this stage, the resin liquid flows along the introduction groove 7 and fills the first cavity 5 .

This resin liquid is made of, for example, an uncured liquid of non-foaming urethane resin, and this uncured liquid is reacted and cured in the cavity 5, forming a sound-insulating skin layer 20 (see Fig. 2). end.

After this skin layer 20 is sufficiently cured, the upper mold 2
When it is pulled up by a predetermined amount from the lower mold 1, the ejector pin 9 is pushed out toward the lower mold 1 as shown in FIG. Also, at this stage, the runner 20a is connected to the introduction groove 7 and the skin layer 2.
It remains attached to 0.

Next, a frame-shaped spacer 21 is interposed between the parting surfaces 4 of both the upper and lower molds 1 and 2 as shown in FIG. A cavity 23 is formed between the skin layer 20 and the upper mold 2.

Note that the ejection pin 9 is housed in the upper die 2 in this state.

Next, if the resin liquid is injected from the resin injection head 11,
This resin liquid flows through the injection hole 8 and is filled into the second cavity 23.

This resin liquid is a soft foamable urethane resin liquid, and this resin liquid foams in the cavity 23 to form a sound-absorbing foam layer 24, and also adheres integrally to the skin layer 20 to form a foam layer 24 at the factory. end.

After sufficiently curing the foam layer 24, the upper mold 2 is raised and the lower mold 1 is lowered, as shown in FIG. As a result of pressing the product, the molded product is demolded, and an insulator dash in which the skin layer 20 and the foam layer 24 are integrated is obtained.

In this example, the thickness of the foam layer 24 is equal to the thickness of the spacer 21 in the flat part of the molded product, but becomes thinner in the inclined part according to the angle of inclination.

However, unlike molded products such as deep-bottomed containers, molded products of this type used as insulator dashes and other vehicle interior parts generally have a relatively gentle curvature, and the wall thickness of the flat part is sufficiently thick. As long as it is configured to be thicker than this, there is no practical problem even if the curved portion is slightly thinner than this.

Further, in the above embodiment, the two layers, the skin layer and the sound absorbing layer, were integrally molded using one molding device and mold, but it goes without saying that even more layers can be formed.

As explained above, in the method for molding a multilayer molded product according to the present invention, a pair of molds whose cavity thickness is made variable by adjusting the pinch-off portion to be close to and separate from each other as a guide are used, and one molding process is performed. In each case, the molded body formed by the above-mentioned mold is fitted into one mold, and the other mold is separated to a desired thickness, and the molded body is formed by this mold and the above-mentioned molded body. By injecting and filling the cavity with resin of a material different from that of the molded body, synthetic resin layers of different materials are integrally molded, so a single molding device and mold can be used. It is now possible to produce multi-layer molded products, reducing the number of production steps.
Moreover, the movement of semi-finished products can be eliminated and the process can be streamlined.

In addition, in this invention, there is no transfer of the molded product to the mold, so mold misalignment and resin leakage can be prevented during this time, and mold manufacturing costs can be reduced, and molding can be performed using a single molding device. Therefore, the installation space can be reduced accordingly, and space efficiency can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a molding apparatus according to the present invention, and FIGS. 2 to 4 are explanatory diagrams showing the order of the method of the present invention. 1, 2...Mold (1...Lower mold, 2...
... Upper mold), 3 ... Pinch-off part, 5, 2
3...Cavity (5...First cavity, 23...Second cavity), 20.
...Skin layer, 24 ... Foam layer.

Claims (1)

[Claims] 1 Using a pair of molds whose cavity thickness is variable by adjusting the pinch-off part to be able to approach and separate as a guide, the molded object formed in the mold is placed in one mold for each molding process. While still in the fitted state, separate the other mold to a desired thickness, and inject and fill the cavity formed by this mold and the above-mentioned molded body with a resin of a material different from that of this molded body. A method for forming multilayer molded products in which synthetic resin layers of different materials are integrally molded.