JPH0442969B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <<Industrial Application Field>> The present invention relates to a method for manufacturing a synthetic resin molded article to which a decorative metal plate is fixed, and the molded article.

《Prior Art》 Synthetic resins are generally used widely in various fields because they not only have excellent mechanical properties such as ease of molding, lightness, and strength, but also because they can be mass-produced at low cost. However, it cannot be denied that it is one step inferior to traditional materials such as metal in terms of external texture and luxury. Therefore, for molded products that require a high-class feel, a metal plate such as aluminum is fixed to the surface of the molded product using adhesive or other methods. There is a method in which a metal plate is fixed to the surface of a molded product that is also formed into a predetermined shape using an adhesive, and an adhesive layer is provided on a metal plate that has been previously processed into a predetermined shape to form an injection mold. A commonly used method is to insert the metal plate into the mold and inject molten resin to fix the metal plate when obtaining a molded product, but both methods require processing of the metal plate, which increases the number of steps. Not only is it complicated;
Since a press mold is required in addition to an injection mold, a considerable increase in costs is unavoidable.

In addition, the applicant has previously installed a punching mechanism in an injection mold, and at the same time punches out a sheet metal plate that is continuously supplied into the mold, the punch is punched out into a recess in the mold. The present invention provides a method for obtaining a metal-attached molded product by supplying metal and then injecting resin into the recess. Although this method uses a single mold and has the advantage of not requiring processes such as gluing metal plates or inserting, it requires the mold itself to be special in order to incorporate the punching mechanism. There was a problem that it became expensive.

<<Problems to be solved by the invention>> The present invention has been made in view of the above-mentioned circumstances, and its purpose is to eliminate the need for processes such as press processing of metal plates and adhesion to molded products, and To provide a method for manufacturing a synthetic resin molded product with a decorative metal plate that does not require a special mold and enables a significant cost reduction, and a synthetic resin molded product with a metal plate that is low cost and suitable for mass production. There is a particular thing.

<Means for Solving the Problems> In order to achieve this object, the method according to the present invention uses a cavity mold in which a relatively shallow opening recess corresponding to the molded product is formed, and a sprue for molten resin. and a core mold configured to close the opening surface of the recess, and an adhesive layer is formed on one side in the form of a continuous sheet between the cavity mold and the core mold. the core mold, in which the mold is closed, the metal plate is fixedly held between the cavity mold and the core mold, and a part of the metal plate is closed to the opening surface of the recess; Then, by injecting molten resin from the sprue into the recess under pressure, the metal plate is stretched and pressed against the wall of the recess, until the metal plate reaches its elongation limit. The metal plate is cut at the periphery of the recess, and the synthetic resin molded product with metal plate according to the present invention is a comparative product molded from synthetic resin by injection molding. A metal plate that is cut into a predetermined shape by being stretched with molten resin during injection molding of the molded product and bonded to one side of the molded product via an adhesive layer. It is characterized by consisting of.

<<Examples>> Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

1 to 4 are schematic diagrams for explaining a manufacturing method according to an embodiment of the present invention, in which reference numeral 1 indicates an injection mold, and this mold 1 is connected to a cavity mold 2. It consists of a core type 3 and a cavity type 2.
A relatively shallow recess 4 with a shape corresponding to the molded product is formed on the upper surface, while the lower surface of the core mold 3 is molded smoothly, and the core mold is equipped with an injection molding machine (not shown). runner 5 and sprue 6 connected to
is drilled. When the mold 1 is closed, the upper surface of the cavity mold 2 and the lower surface of the core mold 3 are in close contact with each other, except for the recess 4, and the opening surface of the recess 4 is in close contact with the lower surface of the core mold 3.
This closed recess 4 is closed by the lower surface of the
The sprue 6 is facing out.

To carry out the method according to the present invention using the mold 1 configured as described above, first, with the mold 1 open, a continuous sheet metal plate 7 is inserted between the cavity mold 2 and the core mold 3. Allocate. This mold plate 7 is preferably made of hard aluminum, has dimensions sufficiently larger than the planar shape of the recess 4, and has a heat-sensitive adhesive layer 7a provided on its upper surface. Next, the mold 1 is closed and the metal plate 7 is fixedly held between the upper surface of the cavity mold 2 and the lower surface of the core mold 3, and a part of the metal plate is inserted along the opening surface of the recess 4. That is, it is positioned along the lower surface of the core mold 3 that closes the opening surface (see FIG. 1).
After that, the molten resin 8 from the injection molding machine is passed through the runner 5.
When the resin 8 is injected into the recess 4 under pressure from the sprue 6, the resin 8 tries to press the metal plate 7 in the recess 4 against the wall of the recess due to the pressure, but the resin 8 Since the other parts are fixed between the cavity mold 2 and the core mold 3 as described above, the recess 4
The inner portion is brought into pressure contact with the wall surface while being stretched due to the elongation characteristics of the metal plate itself (see FIG. 2). Then, when the metal plate 7 is stretched to its limit, the metal plate is cut at the boundary with the fixed part, that is, at the peripheral edge 4a of the recess 4 where bending stress is applied (see Fig. 3). As the resin 8 is filled into the recess 4, it is formed into a shape that follows the wall surface of the recess and is adhered to the resin 8 via the heat-sensitive adhesive layer 7a. Therefore, if the mold 1 is then opened after waiting for the resin 8 to cool and solidify, a molded product 9 having the metal plate 7 fixed to one side can be obtained.

Incidentally, the elongation rate of the metal plate 7 naturally varies depending on the material of the metal plate, but it also varies depending on its wall thickness, and generally, as the wall thickness increases, the elongation rate also increases. Therefore, considering the dimensions of the recess 4, specifically the ratio of the plane area and depth of the recess 4, the metal plate 7
By adjusting the material and wall thickness of the metal plate 7, the metal plate 7 can be cut at the peripheral edge 4a of the recess 4 as described above. In this case, if the elongation rate is too small, the cut metal plate 7 will not be able to cover the edge of the molded product 9;
It is preferable to set the elongation rate so that the elongation limit is reached when the portion located within the recess 4 in FIG. 1 is stretched to an area slightly smaller than the surface area of the recess.

FIG. 5 shows a molded article 9 formed as described above.
A metal plate 7 is fixed to one surface of the metal plate 7 through an adhesive layer 7a. Note that the shape of the molded product is not limited to a simple plate shape, but by changing the shape of the recess 4 of the mold 1, for example, a molded product with holes as shown in FIG. It is also possible to have concave or convex parts as shown in Fig. 8, and to obtain the molded product shown in Fig. 6, the mold shown in Fig. 7 is used, and the mold shown in Fig. 8 is used. For this purpose, a mold as shown in FIG. 9 may be used.

The following describes a prototype experiment conducted by the present inventors. In this experiment, we used a mold 1 in which the dimensions of the recess 4 of the cavity mold 2 were set to 81.6 mm in length, 47 mm in width, and 2.9 mm in depth, and a continuous sheet of hard aluminum with a wall thickness of 80 μm was used as the metal plate 7 in the cavity mold. 2 and the core mold 3, the molten resin was injected into the recess 4 at high speed at an injection pressure of 60 kg/cm ² . Thereafter, when the mold 1 was opened after waiting for the resin to solidify, it was confirmed that the metal plate 7 had been cut along the peripheral edge 4a of the recess 4, and it was possible to obtain the desired molded product with the mold plate. did it.

<<Effects of the Invention>> As described above, according to the method for manufacturing a synthetic resin molded product with a decorative metal plate according to the present invention, a cavity mold in which a relatively shallow opening recess corresponding to the molded product is formed, and a molten resin An injection mold consisting of a core mold having a sprue and a core mold configured to close the opening surface of the recess is used, and a continuous sheet is bonded to one side between the cavity mold and the core mold. A metal plate with a layer formed thereon is arranged, the mold is closed, the metal plate is fixedly held between the cavity mold and the core mold, and a part of the metal plate is inserted into the opening surface of the recess. The metal plate is placed along the surface of the core mold to be closed, and then molten resin is injected into the recess from the sprue under pressure to stretch the metal plate and press it against the wall of the recess. Since the metal plate is cut at the periphery of the recess at the elongation limit of This eliminates the need for a manufacturing process and simply feeds the sheet metal plate continuously into the mold, which greatly simplifies the manufacturing process. It also allows the use of regular injection molds, making it extremely efficient. It's good.

Furthermore, the synthetic resin molded article with a decorative metal plate according to the present invention includes a relatively thin molded article molded from a synthetic resin by injection molding, and a relatively thin molded article that is stretched by molten resin during injection molding of the molded article. It consists of a metal plate that is cut into a predetermined shape and bonded to one side of the molded product via an adhesive layer.
It has a high quality or luxurious feel, has high commercial value, and is suitable for mass production at low cost.

[Brief explanation of drawings]

1 to 3 are cross-sectional views for explaining a method for manufacturing a molded product with a metal plate according to an embodiment of the present invention, FIG. 4 is a partially enlarged view of FIG. 3, and FIG. 5 is a cross-sectional view of the present invention. FIGS. 6 and 7 are a partially cutaway perspective view showing a molded product according to one embodiment of the present invention, and FIG. 9 and 9 are similar views showing a molded article and a mold according to still another embodiment of the present invention. 1...Injection mold, 2...Cavity mold,
3...core type, 4...recess, 4a...periphery, 6
... Sprue, 7... Metal plate, 7a... Adhesive layer, 8...
...resin, 9...molded product.

Claims (1)

[Scope of Claims] 1. A cavity mold in which a relatively shallow opening recess corresponding to a molded product is formed, and a core mold having a sprue for molten resin and configured to close the opening surface of the recess. A metal plate in the form of a continuous sheet with an adhesive layer formed on one side is arranged between the cavity mold and the core mold, and the mold is closed to remove the cavity mold. The metal plate is fixedly held between the core mold and a part of the metal plate is positioned along the surface of the core mold that closes the opening surface of the recess, and then the molten resin is poured from the sprue. By injecting into the recess under pressure, the metal plate is stretched and pressed against the wall of the recess, and at the limit of elongation of the metal plate, the metal plate is cut at the peripheral edge of the recess. A method for producing a synthetic resin molded product with a decorative metal plate, characterized by: 2. The method of manufacturing a synthetic resin molded article with a decorative metal plate according to claim 1, wherein the metal plate is made of hard aluminum. 3 A relatively thin molded article molded from a synthetic resin by injection molding, and the molded article is stretched with molten resin during injection molding, cut into a predetermined shape, and then stretched through an adhesive layer. A synthetic resin molded product with a decorative metal plate, characterized by comprising a metal plate adhered to one side of the molded product.