JPS59150740A - Preparation of multi-layered molded article - Google Patents

Abstract

PURPOSE:To prepare a molded article having a skin material free from wrinkles or rupture provided to the surface thereof, in molding a multi-layered molded article having a skin between a male mold and a female mold, by fixing the peripheral edge of the skin material by a fixing plate. CONSTITUTION:A skin material 9 is placed on the upper abutting surface of a female mold 1 and the rod 7 of an pneumatic cylinder 4 is fallen to grasp the skin material 9 by the lower surface of a fixing plate 6 and the upper surface of the female mold 1. Subsequently, a molten resin 10 is supplied onto the skin material 9 exposed to the opening 5 of said fixing plate 16 by an extruder and, when a lift mechanism is further operated to fall a male mold 2, the molten resin is flowed to press the upper surface of the skin material and the peripheral edge 11 of the skin material is squeezed into the recessed part 3 of the female mold 1 with the falling of the male mold 2 while slipped between the fixing plate 16 and the upper surface of the female mold 1 and both male and female molds are inlaid to complete the integration of the skin material 9 simultaneously with the molding of the core material molten resin 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a multilayer molded article (hereinafter referred to as a multilayer molded article) consisting of a skin and a core resin.

BACKGROUND OF THE INVENTION Plastic molded products are used in large quantities in all fields including automobiles and home appliances due to their economic efficiency, freedom of shaping, and light weight.

On the other hand, there are disadvantages such as cheapness, cold feeling, and easy scratching, and there has been a strong demand for decoration and softness. In the past, various studies have been made to create a fun pound that has the functionality to satisfy these demands, but it has been found that the above drawbacks have been improved while maintaining free formability and strength using a single material. It is difficult to have the desired surface texture, and at present, multilayer molded products that combine multiple materials with different functions are commonly used.

There are many known methods for manufacturing these multilayer molded products, but for example, as proposed in JP-A No. 51-13859 and others, the skin material is preformed by means such as thermoforming. There is a method of placing it in a mold and then injecting core material resin to integrate it. However, this method requires a large number of work steps and devices, and each device and molding method has its own technical problems, so it takes a lot of effort and money to obtain the final product. .

Another method, as proposed in Japanese Patent Publication No. 50-19132 and others, is to use a device that has a vacuum forming function and a core resin injection function in a single mold. Basically, stay within the former category.

Furthermore, as a method to overcome the drawbacks of the above three methods, as proposed in Japanese Patent Application Laid-Open No. 53-63461 (v), an unpreformed skin material is placed in a mold, and a core material resin is used. An integrated method has been proposed. Although this method is economical, the tension can only be controlled in one direction and cannot be controlled in the other direction, which results in wrinkles and makes it difficult to produce molded products with deep three-dimensional drawings. There is a limit in that only relatively simple shapes can be created.

The present invention eliminates the drawbacks of these conventional methods, and provides an extremely economical method for manufacturing multilayer molded products that provides a good appearance without wrinkles or tears on the skin layer of the molded product, and simplifies the work process. The purpose is to provide

That is, the present invention uses a skin material fixing plate that is movably attached to the female die or the male die of a molding device consisting of a female die and a male die, and has an opening through which the convex portion of the male die passes, and the fixing plate After sandwiching the peripheral edge of the skin material between the skin material and the female mold or the male mold, a core material molten resin is supplied between the skin material and the female mold or the male mold, and the female mold and the male mold are brought together to perform molding. The present invention provides a method for manufacturing a multilayer molded product consisting of a skin and a core resin.

The present invention will be explained in more detail below with reference to the drawings showing specific examples of the apparatus used in the method of the present invention. 1st
Figures (a) to (d) are cross-sectional views showing a specific example of a molding device used in the method of the present invention, and the device consists of a lower female mold (1) and an upper male mold (2), both of which to form a molding device. The female mold (1) has a four part (3) corresponding to the outer shape of the molded product in the upper center and a pneumatic cylinder (4) in the side part. The pneumatic cylinder (4) has the female mold (1)
A plurality of rondos (7) fixed to the upper end of a skin material fixing plate (6) which is substantially opposite to the upper surface of the skin member and provided with an opening (5) is slidably housed therein. On the other hand, the male mold (2) is supported by a well-known elevating mechanism (not shown), passes tightly through the opening (5) of the fixed plate (6), and enters the female mold recess (3). A protruding convex portion (8) is provided on the lower surface.

To carry out the method of the present invention using this apparatus, first, as shown in FIG. Next, as shown in FIG. 1(b), the rond (7) of the pneumatic cylinder (4) is lowered and the skin material (
9). Then, the molten resin (10) is passed through the opening (5) using a well-known melt plasticizing means (not shown) such as an extruder.
It is supplied onto the skin material (9) exposed inside. Furthermore, when the lifting mechanism is activated and the male die (2) is lowered, it is shown in Figure 1 (c).
), the molten resin (10) flows and forms the skin material (9).
) Press the upper surface, and the peripheral edge (11) of the skin material (9) without !1' slips between the fixing plate (6) and the female mold (1) -1x surface-) and the female mold ( The concave part (3) of 1) is narrowed down, and finally, as shown in Figure 1 (d), the hermaphrodite (
1) and (2) are combined to complete the molding of the core molten resin (10) and the integration with the skin material (9) at the same time. Also, female type 1
) may be provided with a suction mechanism on the male-type facing surface around the recess,
Thereby, when the skin material is placed, it can be held securely.

In the method of the present invention, as shown in FIG. 1 (1) to (d), the periphery (11) of the skin material (9) needs to gradually move inward as the molding progresses. Setting the fixing force to the material is particularly important. In other words, the skin material (
9) tries to deform into a shape that roughly follows the shape of the male mold (2) as the male mold (2) descends. Here the fixed plate (6)
If the fixing force of This can cause wrinkles.

On the other hand, if the surface constant force is excessive, the skin material will not be able to withstand this tension and will be damaged. In addition, the fixing points of the skin material were fixed, for example, in
If only two opposing sides of the skin material are used as described in No. 3-63461, the amount of skin material supplied to the female mold recess will be unbalanced, and wrinkles will not occur if the structure of the molded product is complex. Although it cannot be prevented, this problem can be solved by fixing the periphery of the skin material as in this specific example. Therefore, by gripping the entire periphery of the skin material with optimal fixing force, it is possible to form a molded product without wrinkles or tears.

To set the fixing force when carrying out the method of the present invention, the material properties, that is, the elongation of the skin material, or the structural properties, that is, the gap between the male and female molds, the drawing ratio, the curvature of each vertex and each side of the molded product, etc. It is necessary to select the optimum value for b, but generally 5-150 kg/c+n' per cross-sectional area of the fixed part is used.

In addition, when setting the required area of the skin material, it is necessary to first use the expanded area of the molded product as a standard, and then reduce this in consideration of the elongation of the skin material, so as to avoid excessive quadrilateral loss. However, it is a matter of course that the area of the peripheral edge of the skin material must not be so small that it will fall off and lose its fixing force when the male and female molds are closed.

The skin materials used in the present invention include woven fabrics, non-woven fabrics, sheets or films made of metal 7 oil, thermoplastic resins, and thermoplastic elastomers, and may be decorated with uneven patterns such as grains, printing, dyeing, etc. A foamed material or a foamed material may also be used.

Furthermore, it is also possible to use these products alone or in the form of a laminate made by laminating two or more of them using an adhesive or the like. When using these skin materials, the tensile stress of the skin material,
In order to adjust elongation, preheating may be performed prior to supply.

In addition, as the core material resin used in the present invention, any resin commonly used in injection molding or extrusion molding may be used. Polymers, thermoplastic resins such as nylon, ethylene-propylene block copolymers, styrene-
Thermoplastic elastomers such as butadiene block copolymers, thermosetting resins such as epoxy resins and phenolic resins, various vulcanized synthetic rubbers, and non-foaming or foamable resins such as 9-rethane for RIMt types; It is possible to use materials containing additives such as inorganic fillers, fillers such as glass fibers, pigments, lubricants, and antistatic agents.

FIGS. 2(a) and 2(b) are cross-sectional views showing other specific examples of the molding apparatus used in the method of the present invention. In this specific example, the fixing plate (6) is vertically disposed from the lower surface of the male mold (2) and is movable up and down to the upper male mold (2) via a plurality of ronds (°7) having a stopper (12) at the lower end. The compression spring (=1) is removed and placed between the male die (2) and the fixing plate (6).
13), it is constantly pressed downward. At the vertical position of the lower surface of the male mold (2), there are four annular parts (14) for housing the spring when contracted. On the other hand, the lower female mold (1) has a resin supply path (1) that opens in its fourth part (3).
5) is provided.

When carrying out the method of the present invention using the molding apparatus of this specific example, as shown in FIG.
(9) is placed and molten resin (10) is supplied through the resin supply path (15), the upper male mold (2) is lowered, and the fixing plate (6) is brought into contact with the skin material (9). After fixing the skin material, the male mold is further lowered to perform molding.

In this case, the fixing force of the skin material is determined by the spring constant of the compression spring (13), so in addition to a single spring, a combination spring consisting of springs with different spring constants depending on the purpose may be used. good.

Further, as shown in Fig. 2(b), the skin material is placed on the lower female mold (1), the upper male mold (2) is lowered, and the fixing plate (6
) to fix the skin material (9), and then the male mold (2)
is lowered to squeeze the skin material (9) to an intermediate stage, and then melted through the resin supply channel (15).

The resin (10) may be supplied and molded.

FIG. 3 is a sectional view showing still another specific example of the molding apparatus used in the method of the present invention, in which the female mold (1) and the male mold (2) are arranged upside down and in the direction of the female mold recess. The molding apparatus has basically the same structure as the molding apparatus shown in FIGS. 2(a) and 2(b) except that the male mold (2) is provided with a resin supply path (15) for supplying molten resin.

When carrying out the present invention with this device, the lower male mold (2
) The skin material (9) is placed on the fixing plate (6) attached to the female mold (1), and then the skin material (9) is fixed between the female mold (1) and the resin supply path (15) provided on the male mold. Molten resin (10) is supplied between the skin material (9) and the male mold (2) to perform molding.

As described above, according to the method of the present invention, a multilayer molded product having a good appearance without wrinkles or tears in the skin layer can be manufactured extremely economically through simple working steps.

In addition, since the method of the present invention does not mold the core material by injection molding, a multilayer molded product with less residual stress due to orientation etc. and less deformation such as twisting can be obtained.

Furthermore, since the effective pressure required to shape the core material resin is small, it prevents the foam layer from collapsing when a foam sheet is used as the skin material, and prevents the raised portion from collapsing when using a raised woven fabric. It is possible to maintain a favorable texture in molded articles.

The method of the present invention will be explained in more detail below using Examples and Comparative Examples.

EXAMPLE A multilayer molded product was manufactured using the molding apparatus shown in FIG. First, the skin material was placed on the mating surface of the female mold located downward, and then the pneumatic cylinder was activated to lower the fixing plate, and the area around the skin material was fixed under a pressure of 70 kg/cm2. Then, the resin temperature was increased to 25% using a portapu extruder.
The molten phase 1117 at 0°C was supplied onto the skin material, and the male mold positioned above was further lowered to close both male and female molds, thereby integrating the skin material and the core material. As a result, a good multilayer molded product was obtained without wrinkles, tears, or pressure cleaning of the foam layer. The materials used and the products obtained are as follows.

Skin material 0.311IIn thick thermoplastic elastomer (resident TP
E Well 1800 (manufactured by Sumima Kagaku Kogyo Co., Ltd.) with a foaming ratio of 1
A two-layer sheet made of laminated cross-linked polypropylene foam sheets with a thickness of 5 times and a thickness of 2 m Ifl, the core material resin melt 70-index is 30 g/10 minutes (230 ° C.
/2゜16kg load) ethylene-propylene block copolymer (Jumin Noblen AZ564, Jumin Chemical Industry (
(manufactured by Co., Ltd.) Molded product shape Length 160 +n+nX Width 16On+mX Height? On+m
Box shape with thickness 4II1m, each vertex and side radius 5m+
Comparative Example 1 forming an arc of n A multilayer molded product was manufactured using the same skin material and core resin as in the example, but with the molding device used in the example (Figure 1) except for the skin material fixing mechanism. I did it. Of the four sides, only two of the facing sides were fixed to the upper mating surface of the female mold using double-sided tape. The molten resin was supplied and the skin material and the core material were integrated under the same operations and conditions as in the moxibustion example to obtain a molded product having the same shape as in the example. The skin layer of the obtained molded product had large wrinkles at each bottom vertex and two unfixed sides.

Comparative Example 2 Molding was carried out in the same manner as in Comparative Example 1 except that all four sides around the skin material were fixed to the upper mating surface of the female mold with double-sided tape. The skin layer of the obtained molded article had large cracks at each vertex and each side of the bottom.

Comparative Example 3 A 7S product was manufactured using the same skin material and core resin as in Example 1. The molding device is the device used in the example (Fig. 1)
A male type nest (not shown) was converted and a center direct date was attached as a means for supplying molten resin. This was attached to an injection molding machine together with the female mold, and with the mold open, the area around the skin material was fixed to the upper mating surface of the female mold with double-sided tape. Then, the female mold was moved forward to close both male and female molds, and molten resin at a resin temperature of 2 SO'C was injected through the gate.

The skin layer of the obtained molded product was severely torn, and the foam layer was significantly crushed.

[Brief explanation of the drawing]

FIGS. 1(a) to (d) are schematic explanatory diagrams showing a cross section when manufacturing a multilayer molded product using an example of the apparatus used in the method of the present invention, and FIGS. 2(a) to (b) and FIG. 3 are both schematic explanatory diagrams showing a cross section of a specific example of a pond. The main symbols in the figure are as follows. 1: Female type, 2: Male type, 3: Recessed part, 5: Opening, 6: Fixed plate, 8: Convex part, 9: Skin material,
10: Molten resin, 15: Resin supply route. Patent applicant: Sumitomo Chemical Co., Ltd. Figure 1 (0) Figure 1 (c) Figure 1 (b) Figure 1 (d)

Claims (7)

[Claims] (1) A skin material fixing plate is movably attached to the female die or the male die of a molding device consisting of a female die and a male die, and has an opening through which the convex part of the male die passes, and the fixing plate and the female die are connected to each other. After the peripheral edge of the skin material is held between the openings of the skin material and the female mold or the male mold, molten core material TJ1 fat is supplied to the opening between the skin material and the female mold or the male mold, and the female mold and the male mold are closed to perform molding. A method for manufacturing a multilayer molded product consisting of a skin and a core resin. (2) The periphery of the skin material is held between the female mold and a skin material fixing plate movably attached to the female mold located below, and the core material molten resin is supplied to the upper surface of the skin material. Said (1st
) manufacturing method. (3) The manufacturing method according to item (1) above, in which molten resin is supplied into the female mold through a resin supply path provided in the female mold located below. (4) Sandwich the periphery of the skin hole between the skin material fixing plate and the female mold located below, bring both the male and female molds close to the position where the skin material has been squeezed to an intermediate stage, and then place it on the female mold. O received
(The manufacturing method according to item (1) above, in which the 1ζ molten resin is supplied into the female mold through the fat supply path. (5) Melt + through the resin supply path provided in the male mold located below! (The manufacturing method according to item (1) above, in which fat is supplied between the skin material and the male mold. (6) Item (1) above, wherein the means for pressing the skin material fixing plate into the female mold is a pneumatic sillage mechanism or a hydraulic cylinder mechanism.
The manufacturing method according to any one of Items to Items (5). (7) The manufacturing method according to any one of items (1) to (5) above, wherein the means for pressing the skin material fixing plate into a female shape is a spring.