JPS6258889B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is capable of molding an injection molded product having a two-layer structure of a surface layer and a molding material, without causing wrinkles or deformation on the surface layer surface, and in which the molding material breaks through the surface layer and protrudes. The present invention relates to a method for molding an injection molded article with a surface layer having a shape.

Conventionally, when molding an injection molded product with a surface layer having a small designed wall surface such as one gate, as shown in FIG. It is attached to a mold 1, the female mold 1 and the male mold 2 are clamped, and a molding material 5 having the same or different flexibility as the resin sheet is injected into the molding gap 7 through the gate 3. In this way, the resin sheet and the molding material were fused and integrated to form an injection molded product with a surface layer.

However, molding of an injection molded product with a surface layer by such a method has the following drawbacks. That is, (1) the resin sheet 6 attached to the designed wall surface 4 of the female mold 1 is partially moved as the molding material 5 flows and is expanded or compressed, causing wrinkles and deformation on the surface layer of the injection molded product. Otherwise, significant elongation deformation occurs locally, causing the resin sheet 6 to break and the molding material 5 to be partially exposed.

(2) It is necessary to cut and prepare a resin sheet 6 having a width corresponding to the size of the design wall surface 4 in advance.

(3) When two or more gates 3 are provided to mold an injection molded product with a large surface layer on the designed wall surface 4, a resin sheet is placed on the weld line (WELD LINE) that occurs at the confluence of the flows of molding material from each gate. There is an unavoidable problem that the material is stretched or compressed, and this causes wrinkles and deformation on the surface layer, making it impossible to maintain product quality and mass production.

(4) Due to the reasons (1) and (3) above, the size of the product is restricted, and it is not possible to diversify products in which the molding material 5 breaks through the resin sheet and protrudes.

There are drawbacks such as.

The present invention was arrived at as a result of intensive research aimed at solving the above-mentioned drawbacks of conventional methods.It does not cause wrinkles or deformation on the surface layer, and moreover, it does not pierce the surface layer on the inner surface of the molded product. This invention relates to a method for molding an innovative injection molded article with a surface layer in which the molding material protrudes. That is, the present invention is an injection molded product having a two-layer structure in which a surface layer made of a resin sheet and a molded material part formed by injection molding are partially laminated, and the molded material part is substantially exposed. A method for molding an injection molded product consisting of an inner surface forming a central designed wall surface and an outer peripheral section surrounding the entire periphery of the inner surface, wherein a resin sheet is applied to the central portion forming the inner surface. A recess 9 having a depth greater than the elongation at tensile break of the resin sheet, and a recess 10 having a depth equal to or less than the elongation at tensile break of the resin sheet in the peripheral portion forming the outer periphery. Preparing a female mold 1 having a recess 10 arranged to completely surround the entire periphery; a substantially mold having a plurality of gates opening at the boundary between the central recess 9 and the peripheral recess 10; preparing a male mold 2 having a flat surface; supplying and disposing a molded substantially endless resin sheet wider than the width of both molds between the female mold 1 and the male mold 2; , bringing both molds close to a predetermined position, and injecting the molding material into the recesses 9 and 10 of the female mold from the gate of the male mold; and the resin sheet arranged in the central recess 9 of the female mold. The recess 9, which was partially broken by the injected molding material, is filled with the molding material, and the resin sheet disposed in the peripheral recess 10 is not broken by the injected molding material, and the bottom of the recess 10 is filled with the molding material. The present invention relates to a method for continuously molding an injection molded article with a surface layer, which comprises the steps of forming a two-layer structure by laminating a resin sheet and a molding material.

An embodiment of the present invention will be described below based on the drawings.

As shown in FIG. 2, the injection mold used in the present application consists of an outer circumferential portion A and an inner surface B located inside the outer circumferential portion A and surrounded by the outer circumferential portion A.
From a recess 10 having a depth equal to or less than the elongation of the resin sheet 6 at tensile break on the outer circumference A of the designed wall surface and a recess 9 having a depth greater than the elongation of the resin sheet at tensile break on the inner circumference B of the designed wall surface. Female molds 1 and 2 to be formed
It is composed of a male mold 2 having two gates 3 and 3'. When molding the injection molded product, as shown in FIG. 3, a rolled resin sheet 6 having a width sufficient to cover the designed wall surface of the female mold 1 was placed above the male and female molds 1 and 2 in advance. The resin sheet 6 is set on the shaft 11, pulled down and installed between the male and female molds 1 and 2 when the molds are open, and after the male and female molds are clamped, the molding material 5 is injected and held for a certain period of time. After cooling, the mold is opened to obtain an injection molded product 8. In this application, the completed injection molded product 8 is suspended below the mold without being cut from the sheet, and the resin sheet 6
is on a continuous line from the upper shaft 11 to the lower injection molded product 8.

By doing this, the weight of the injection molded product 8 hanging down below the mold applies a certain tension to the resin sheet 6 starting from the shaft, causing wrinkles and deformation in the resin sheet 6. The resin sheet 6 can be easily attached to the mold without any problems, and the resin sheet 6 can be prevented from being compressed or expanded as the molding material 5 flows.

Next, a recess 10 having a depth within the elongation of the resin sheet at tensile breakage is provided on the outer periphery A of the designed wall surface 4 of the female mold 1 to which the resin sheet 6 is attached, and the recess provided on the outer periphery A of the designed wall surface is 10, that is, the inner periphery B of the designed wall surface, is provided with a recess 9 having a depth greater than the elongation of the resin sheet at tensile breakage.
The male and female molds 1 and 2 are clamped, the molding material 5 is injected, the mold is cooled for a certain period of time, the mold is opened, and the injection molded product 8 is taken out. The sheet 6 wraps the molded material 5 to form an uneven design, and the molded material 5 breaks through the resin sheet 6 at the inner periphery B of the designed wall surface 4, resulting in a shape protruding from the surface of the resin sheet 6. An injection molded product having the surface layer of the present application is obtained with the above configuration.

The conditions for implementing the present invention are as follows: The depth of the recess provided on the designed wall surface of the female mold is within the elongation of the resin sheet 6 at tensile breakage at the outer periphery A of the designed wall surface, and at the inner periphery B of the designed wall surface. The elongation is designed to be greater than the elongation of the resin sheet 6 at tensile break. The depth of this recess is determined by the amount of elongation of the resin sheet at tensile breakage, but if the depth of the recess is specified, the material of the resin sheet,
Just adjust the thickness.

In this application, the reason why the depth of the recess is defined by the outer periphery and the inner surface of the design is to prevent a tear in the resin sheet from being transmitted to the outer periphery.

As the molding material, vinyl chloride resin is preferred, but thermoplastic materials that can be fused and integrated with the resin sheet, such as inexpensive materials such as recycled vinyl, can also be used.

Any material can be used for the resin sheet as long as it has thermoplasticity, but a soft vinyl chloride resin sheet is preferred, for example.

The thickness of the resin sheet is preferably in the range of 0.1 to 1 m/m, and if it is less than 0.1 m/m or more than 1 m/m, it is difficult to fully exhibit the effects of the present invention.

The shaft 11 wrapped with the resin sheet is designed to remain stationary after delivering one shot of the sheet, since it is necessary to apply appropriate tension to the sheet.

The temperature of the male and female molds is adjusted to a range of 20 to 50°C.

It is preferable that the width of the smooth surfaces of the bottom of the recess and the surface of the convex part (C and D in Figure 5) provided on the designed wall surface is within a range of not exceeding 20 m/m, and when it exceeds 20 m/m, the effect of the present invention is not exhibited. It's hard to get caught.

Male and female mold design The uneven design provided on the wall surface can have various shapes depending on its purpose and use.
An example of this is a continuous groove shape (fourth and fifth grooves).
), a discontinuous conical shape (FIGS. 6 and 7), a pyramidal shape, a truncated pyramid shape, a cylindrical shape, or a combination of these shapes, but the shape is not limited to any of them.

The number of gates is determined by the size and shape of the designed wall, and at least two gates are required.

The present invention having the above configuration can mold an injection molded product with a surface layer in which the molding material protrudes in an intended shape on the surface layer without causing wrinkles or deformation on the surface layer, and is superior to conventional products. As a result, an injection molded product with a large designed wall surface can be obtained without causing wrinkles or deformation on the surface layer, and the installation of the resin sheet is extremely easy, so there is no need to cut the resin sheet to specified dimensions in advance, reducing the number of man-hours. Furthermore, since recycled vinyl can be used as a molding material, costs can be reduced, and vinyl scraps, which can cause pollution if left untreated, can be effectively recycled, saving resources and saving resources. This is a useful invention that leads to pollution prevention.

The injection molded product thus produced can be used for a variety of purposes, such as automobile mats, entrance mats, bath mats, etc., and the effects of the present invention are very large.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an injection molding die using a conventional method for molding an injection molded product with a surface layer having a small designed wall surface. FIG. 2 is a sectional view of the injection molding mold of the present invention. FIG. 3 is a sectional view showing an embodiment using the injection mold shown in FIG. 2. FIGS. 4 and 6 are part of a plan view showing one embodiment of the shape of the female mold recess. Figure 5 is the 4th
7 shows a sectional view of FIG. 6. FIG. 8 is a perspective view of an example of a female mold of the injection mold used in the present invention. Figure 9 shows the X-
FIG. 1...Female mold, 2...Male mold, 3...Gate,
4... Design wall surface, 5... Molding material, 6... Resin sheet, 7... Molding void, 8... Injection molded product, 9...
...Concavity having a depth greater than the elongation at tensile break, 1
0... Concavity having a depth within the elongation at tensile breakage, 11... Shaft, A... Outer periphery of designed wall surface, B... Inner periphery of designed wall surface, C... Smooth surface of recess, D... ...Smooth surface of convex part.

Claims (1)

[Scope of Claims] 1. A two-layer injection molded product formed by partially laminating a surface layer made of a resin sheet and an injection-molded molding material, in which the molding material is substantially exposed. A method for molding an injection molded product consisting of an inner surface that forms a central designed wall surface, and an outer peripheral section that completely surrounds the inner surface, wherein the central portion that forms the inner surface is A recess 9 having a depth greater than the elongation at tensile break of the resin sheet, and a recess 10 having a depth less than the elongation at tensile break of the resin sheet in the peripheral portion forming the outer periphery, said recess. Prepare a female mold 1 having a recess 10 arranged so as to completely surround the entire periphery of the mold 9, and having a plurality of gates opening at the boundary between the central recess 9 and the peripheral recess 10. preparing a male mold 2 having a substantially flat surface; supplying and disposing a molded substantially endless resin sheet wider than the width of both molds between the female mold 1 and the male mold 2; Bringing both molds close to a predetermined position, and injecting the molding material into the recesses 9 and 10 of the female mold from the gate of the male mold; Resin disposed in the central recess 9 of the female mold. The sheet fills the recess 9, which has been partially broken by the injected molding material, with the molding material, and the resin sheet disposed in the peripheral recess 10 fills the recess 10 without being broken by the injected molding material. A method for continuously molding an injection molded product with a surface layer, which consists of the steps of pressing the resin sheet and the molding material to the bottom to form a two-layer structure.