JPH0122130B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a double-molded synthetic resin article.

A synthetic resin double-molded product with a metal plating, such as chrome plating or nickel plating, on the inside, and a transparent synthetic resin with a certain shape on the outside. The inner metal plating surface can be seen through, giving it a cleaner feel compared to products made from metal materials that are prone to rust and quickly lose their surface luster. It is widely used in faucet knobs, precision machine knobs, interior decoration ornaments, nameplates, etc. Such double-molded synthetic resin products (hereinafter referred to as double-molded products) are synthetic resin molded products (hereinafter referred to as double-molded products) that are made of acrylic resin, polystyrene resin, ABS resin, etc., and have metal plating on the surface. An inner molded product) is prepared in advance, and this is inserted and fixed into a mold for forming a transparent synthetic resin molded product that forms a molding surface of a fixed shape on the outside. It is obtained by press-fitting a synthetic resin raw material into the mold cavity and integrating it with an inner molded product whose surface is plated with metal. However, in the double molded product made in this way, there is a difference in shrinkage during molding or a difference in shrinkage during molding at the joint surface between the inner molded product and the outer molded product made of transparent synthetic resin (hereinafter referred to as the outer molded product). It is inevitable that a slight gap will occur due to deformation. Therefore, after using it for a long time on water faucet knobs, for example,
The drawback was that dust, water, etc. could enter through the gaps, significantly impairing the beauty of the molded product. The present invention provides a double-molded product free from such drawbacks, in which a transparent synthetic resin solution is applied to the metal plating surface of the inner molded product, and this is applied to the molding die for the transparent outer molded product. Manufacture of double-molded products that are inserted and fixed into a cavity, and the gap is sealed by press-fitting a transparent synthetic resin raw material into the cavity, which maintains its beauty forever with a structure that does not allow dirt or water to enter. It provides law.

Hereinafter, the case of obtaining a water tap knob by the method of the present invention will be explained based on the drawings.

1 and 2 show a cross-sectional view and a perspective view of an inner molded product according to the method of the present invention. The inner molded product consists of a cylindrical body 1 made of synthetic resin with a conical top and a through hole 2 for a fixing metal bolt to be attached to an on-off valve of a water faucet. is applied. Examples of the synthetic resin constituting the main body 1 include ABS resin, acrylic resin, polystyrene resin, etc.
Further, examples of the metal plating 3 on the surface include chrome plating, nickel plating, copper plating, etc.
It is constructed by well-known electrolytic plating, vacuum evaporation, etc. Note that characters, figures, symbols, etc. may be written on the surface of this metal plating 3 as desired.

The present invention applies a transparent synthetic resin solution film 4 to the surface of the inner molded product 1 (metal plating surface) by an artificial or mechanical method,
A synthetic resin layer is made, and it is inserted and fixed by artificial or mechanical means into the cavity of a mold to form a molded product with a certain shape on the outside, and a transparent synthetic resin, such as an acrylic resin, molten in the cavity is Alternatively, polystyrene resin is press-fitted. Specific examples of the transparent synthetic resin solution used here include phenolic resin, polyurethane resin, melamine resin with a hardening agent added, alkyd resin, vinyl acetate resin, acrylic ester resin, methacrylic ester resin, polyvinyl ether resin, etc. Examples include solutions of benzene, acetone, and other organic solvents at a certain concentration selected as suitable for dissolving these synthetic resins.

FIG. 3 is a partially enlarged schematic cross-sectional view showing the state in which the inner molded product 1 is inserted and fixed in the mold cavity, where 5 is the mold body, 1 is the inner molded product, and 6 is a metal bolt hole for fixing. As shown in FIG. 4, molten transparent synthetic resin is injected from an injection port (not shown) to form the outer molded product 7, and as shown in FIG. The transparent synthetic resin solution film 4 applied to the surface of the molded product is integrated with this to form a double molded product in which the inner molded product 1 and the outer molded product 7 are joined without any gaps. Incidentally, in FIGS. 3 and 4, attached devices for taking out the formed double molded product from the mold 5 are not particularly shown, but devices based on various known methods can be applied to these devices. Ru.

As described above, the present invention integrates a metal-plated synthetic resin molded product with a certain shape inside a transparent synthetic resin molded product with a certain shape, so that the internal metal-plated surface When manufacturing double-molded synthetic resin products that are transparent and aesthetically pleasing, the metal-plated inner synthetic resin molded product is coated with a transparent synthetic resin solution before being inserted and fixed into the mold. A double molded product in which the surface of the inner synthetic resin molded product and the outer transparent synthetic resin molded product are joined without any gaps by injecting and press-fitting a molten transparent synthetic resin raw material into the mold. Compared to conventional double molded products of similar structure, the gap between the inner and outer molded products is sealed by applying the synthetic resin solution. , there is no fear of dirt or water intrusion,
When applied to door knobs, water faucet knobs, etc. inside a house, the beautiful luster of the metal plating surface will not be lost forever, and the decorativeness and durability can be maintained.

[Brief explanation of drawings]

1 and 2 are a sectional view and a perspective view of an example of the inner molded product used in the method of the present invention, FIGS. 3 and 4 are schematic diagrams showing the state of molding according to the method of the present invention, and FIG. The figure is an overall perspective view of a double molded product produced by the method of the present invention. 1... Inner molded product, 2... Through hole, 3... Metal plating, 4... Synthetic resin solution film, 5... Mold body, 6... Core, 7... Outer molded product.

Claims (1)

[Scope of Claims] 1. In manufacturing a synthetic resin double molded product in which a metal-plated synthetic resin molded product of a fixed shape is integrally provided inside a fixed-shaped molded product made of a transparent synthetic resin. , the metal-plated synthetic resin molded product having a certain shape is coated with a transparent synthetic resin solution on the surface and inserted and fixed into the mold cavity of the transparent synthetic resin molded product, and then, A method for producing a double-molded synthetic resin product, which comprises press-fitting a molten transparent synthetic resin into the mold cavity. 2 Claims that include a chrome-plated or nickel-plated synthetic resin molded product with a certain shape coated with a transparent synthetic resin solution and inserted and fixed into a mold cavity for molding the transparent synthetic resin molded product. A method for producing a synthetic resin double molded product according to item 1.