JPH0359814B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a plastic armrest, and more particularly to a method for manufacturing an armrest in which part of the surface of the armrest has a different texture or color.

In recent years, automobiles have been made lighter from the perspective of energy conservation, and there is a strong demand for interior parts such as armrests.

Therefore, in armrests, conventional core materials,
Instead of structures made of elastic foam and skin material, hollow bodies made of plastic have been proposed.

By the way, in order to obtain this hollow armrest, it is suitable to use the well-known plastic hollow molding method, and the armrest can also be made lightweight.As the name suggests, an armrest for an automobile is not only an armrest, but also an armrest for opening and closing a door. They are often used as handles for commercial purposes, and require a certain amount of strength (rigidity), as well as a soft feel similar to furniture and an aesthetic that blends in with other parts of the vehicle, such as a desired multicolored design. However, it has been almost impossible to obtain an armrest that has the required strength, soft feel, and aesthetic appearance using the above-mentioned blow molding method using a single piece of plastic. In addition, in order to obtain a soft feel, the parison (an extrusion molded product of molten plastic, usually a cylindrical body, used to obtain a molded product in blow molding) is made of two layers, and the outer layer is a foamed plastic layer. Some proposals have been made to give the body armrests a soft feel, but it is difficult to apply a desired multicolored design to the surface of the armrests, resulting in monochromatic and monotonous designs.

Therefore, the present invention seeks to provide a method for manufacturing a multicolored armrest that has a soft feel at desired locations and has clear color boundaries,
The gist of this is that at least a part of the parison is multilayered, and the parison is sandwiched between a split mold so that the base layer and the multilayer part of the parison or the boundary between the multilayer parts are outside the cavity of the split mold. The method of manufacturing an armrest includes molding the armrest into a desired shape by applying pressure fluid to the armrest and then pressurizing the armrest with pressure fluid.

The present invention will be explained below based on Examples.
The figure is a front view of the main parts of the blow molding device, Figure 2 is a cross-sectional view taken along the line A-A in Figure 1 showing the positional relationship between the parison and the split mold, and Figure 3 is a cross-sectional view of the parison after the split mold is closed. FIG. 1 is a cross-sectional view taken along the line A-A in FIG. 1 showing the main part of the armrest in a state of being worn, and FIG. 4 is a perspective view of the armrest after molding.

In FIG. 1, 1 is a die for discharging a parison 2, and is connected to the head of an extruder (not shown). In order to make the parison 2 multi-layered or multi-colored, a necessary number of extruders are connected through a die. 3
are divided molds 31, 32, 33, and cavities 41, 42, 4 having a desired armrest shape.
It has 3. Note that these split molds 3 are configured to be closed at predetermined positions by a mold clamping device (not shown). 5 is a blow pin for blowing pressure fluid (usually high pressure air) into the parison. Note that the blow pin may be provided approximately at the center of the lower surface of the die. In the apparatus configured in this way, first, the parison 2 is discharged from the die 1.
At this time, as shown in FIG. 2, the parison 2 is composed of a base layer 21 and an outer layer 22 of a plastic layer of a different type or color, so that at least a part of the circumference is multilayered. For example, the base layer 21 is made of polypropylene resin, and the outer layer 22 is made of foamed vinyl chloride resin. Note that these partial multilayers are made by merging these resins within the die 1. Therefore, different or different colored resins of a predetermined width are continuous in the longitudinal direction of the parison. However, due to changes in the temperature of the molten resin, fluctuations in the driving voltage of the extruder, etc.
The boundary between the general part and the heterogeneous part is usually meandering.

When the parison thus discharged reaches a predetermined length, the split mold 3 is closed. At this time,
The base layer 21 and the outer layer 22 are clamped so that the boundary 23 is outside the cavity. In this case, it is preferable to inject pressure fluid into the parison 2 little by little in advance and close the split mold 3 while slightly expanding the parison. This is because the boundary portion 23 that is not clamped by the cavity portions 41 and 43 tends to escape to the outside of the split mold 3. Therefore, the boundary portion 23 is pinched and pressed against the mold joint surface outside the cavity, resulting in a so-called burr. However, most of the base layer 21 and the outer layer 22 are located within the cavity of the split mold, and the two layers are pressed together by the end of the cavity to form a clear boundary. After the split mold 3 is closed in this way, pressure fluid is blown into the parison 2 to inflate the parison 2 and press it against the cavity surface to shape it into a desired armrest shape.
After cooling, the split mold 3 is opened, the molded product is taken out, and the burrs at the boundary are removed. An example of the molded product is shown in FIG. In this embodiment, as shown in cross section in FIGS. 5 and 6, the base layer 21 is covered with an outer layer 22 of foamed soft vinyl chloride resin on the upper part and the mounting surface side. In this embodiment, the boundary line 6 is provided in the middle of the front of the armrest, and the mounting hole 7 is provided from the bottom of the front surface to the top of the mounting surface.
Although the mold is divided into three parts so as not to form an undercut, the divided structure of the mold is determined by the shape design of the armrest, such as these boundary lines 6 and the presence or absence of an undercut. Furthermore, in the above, an example was described in which only a type of foreign outer layer 22 was provided on a part of the surface of the parison, but the parison 2 may have a two-layer structure including an inner layer of the base layer and a different or different color outer layer, for example, over the entire circumference of the parison 2. The inner layer may be a rigid plastic layer after molding, and the outer layer may be a continuous layer of partially different colored or different layers, so that the surface feel and color tone can be set arbitrarily. It goes without saying that a multilayer structure of two or more layers may also be used.

As described above, the present invention makes at least a part of the parison a multilayer consisting of a base layer and an outer layer of a different or different color, and the boundary between the base layer and the outer layer of a different or different color, or the boundary between the different or different colors. The parison is clamped and closed with a split mold so that it is outside the cavity of the split mold, and then pressurized fluid is injected into the parison to form the desired armrest shape, and then the boundary portion is removed. The boundary line between the base layer and the outer layer of different nature or different color, or the border line between the outer layer of different nature or different color is clearly demarcated, and by making the outer layer of the multilayer part a colored foam layer of soft vinyl chloride resin, etc., it is possible to create any color and color. A soft armrest can be obtained, and desired rigidity and strength can be obtained by selecting the plastic that constitutes the base layer.

[Brief explanation of drawings]

Figure 1 is a front view of essential parts of a blow molding apparatus used in the present invention, Figure 2 is a sectional view taken along line A-A in Figure 1, and Figure 3 is a sectional view taken along line A-A in Figure 1.
The figure is an enlarged sectional view of the main part showing the closed state of the split mold,
FIG. 4 is a perspective view of an armrest obtained by the present invention, and FIGS. 5 and 6 are B-B in FIG.
It is a sectional view taken along the line CC.

Claims (1)

[Claims] 1. In a method for manufacturing an armrest by a blow molding method, at least a part of the parison is made into a multilayer consisting of a parison base layer and an outer layer of different nature or color from the base layer, and the boundary between the base layer and the outer layer or A method for manufacturing an armrest, which comprises clamping a parison with a split mold so that the boundary between the outer layers is outside the cavity of the split mold, and then pressurizing fluid into the parison to form a desired armrest. .