JPS59150741A - 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 15 is applied to the surface 3 opposed to a male mold of a female mold 1 and held while sucked by a suction line 6. In the next step, the rod 10 of a pneumatic cylinder 7 is moved to the female mold direction to grasp the skin material 15 predetermined force exerted by a fixing plate 9 and the aforementioned female mold 1 and, thereafter, suction force is released. Subsequently, when a moving mechanism is operated to advance the female mold 1, the skin material 15 is pressed and the peripheral edge 16 of the skin material 15 is squeezed into the recessed part 4 of the female mold 1 with the advance of the female mold 1 while slipped between the fixing plate 16 and the female mold 1 and, at last, both female and male molds 1, 2 are closed while a core material molten resin 11 is injected between the skin material 15 and the male mold 2 from the supply orifice 12 of the male mold 2 to complete the integration of the skin material 15 simultaneously with molding.

Description

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

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

However, -power has disadvantages such as cheapness, cold feeling, and easy scratching, and 1.1ji such as decorativeness and soft feeling have been strongly sought after. In the past, various studies have been made to obtain a powder with functions that satisfy these demands. It is difficult to achieve the desired properties, and at present, multilayer molded products that combine multiple materials with different functions are commonly used.
do.

There are many known methods for manufacturing these multilayer molded products, but for example, as proposed in JP-A-51-13859, the skin material is pre-Q formed by thermoforming or other means, There is a method of placing this 1L 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 labor 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, it doesn't go beyond the former.

Furthermore, as a method to overcome the drawbacks of the above three methods,
As proposed in 3i1 No. 53-63461,
A method has been proposed in which an unpreformed skin material is placed in a mold and integrated with a core resin. Although this method is economical, the tension is controlled only in one direction, and only in the direction of the pond, so wrinkles occur and it is difficult to obtain molded products with deep two-dimensional patterns. However, there are limitations in that only relatively simple shapes can be obtained.

The present invention eliminates the drawbacks of these conventional methods, and provides an extremely economical method for producing 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 which is movably attached to the female mold or the male mold of a molding device consisting of a female mold and a male mold, and has an opening through which the convex part of the male mold passes, After sandwiching the periphery of the skin material between the fixed plate and the female mold, the female and male molds are closed and the skin material is squeezed into the female mold for pre-shaping, and then the skin material and the female mold are squeezed. The present invention provides a method for manufacturing a multilayer molded product consisting of a skin and a core resin, in which a core 4 molten resin is supplied between a mold or a male mold to perform molding.

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. FIGS. 1(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 female mold (1) and a male mold (2), both of which to form a molding device.

The female mold (1) is supported by a well-known moving mechanism (not shown), has a side surface (3) facing the male mold, and has four parts (4) in the center corresponding to the outer shape of the molded product, The recess (4) has a suction line (6) that opens in the male mold facing surface (3) and communicates with the female mold back surface (5), and is provided with pneumatic sills (7) at the upper and lower parts. The pneumatic shilling-(7)
A plurality of ronds (10), which are substantially opposite to the male mold facing surface (3) of the female mold (1) and have a skin material fixing plate (9) provided with an opening (8) fixed to the tip, are used for sliding. It is movably stored.

On the other hand, the male mold (2) has a supply hole (12) for injecting the core material molten resin (11), and an opening (8) in the fixing plate (9).
The female die facing surface (14) is provided with a convex portion (13) that penetrates the inside in a tight state and projects into the female die recess (4).

To carry out the method of the present invention using this device, as shown in Section 1 (a), the skin material (15) is brought into contact with the male mold facing surface (3) of the female mold (1), Climb up to the suction line and suction and hold. -) Gini fjS1 As shown in Figure (1)), move the ronds (H, l) of the pneumatic cylinder (7) toward the female mold and use the fixing plate (9) and the female mold (1) to After clamping the material (15) with a predetermined fixing force, the suction is released. -], operate the moving mechanism and move the female mold (1) to 11
When advanced by 1j, the skin material (15
) is pressed 11:, and as a result, the peripheral edge (1 (3)) of the skin material (15) slips between the fixing plate (9) and the female mold (1), and the four parts (1) of the female mold (1) are pressed.・1), and finally, as shown in Figure 1 ((1), hermaphrodites (1) (2)
) is closed, the core material molten resin (11) is injected between the skin material (15) and the male mold (2) through the supply hole (12) of the male mold (2), and the core material molten resin (11) is injected between the skin material (15) and the male mold (2) at the same time as molding. Integration is complete.

In the method of the present invention, as shown in Fig. 1 (1) to (d), the peripheral edge (16) of the skin material (15) needs to gradually move toward the inner hole as the molding progresses. Setting the fixing force applied to the skin material is particularly important. That is, the skin material (15) tends to deform into a shape that substantially follows the shape of the female mold (1) as the female mold (1) advances. Here, if the fixing force by the fixing plate (9) is too small, the skin material will be female-shaped (1
) and the fixing plate (9) open, a large amount of slipping occurs, and more surface material than is necessary for shaping the molded product is supplied into the female mold, causing wrinkles.

On the other hand, if the fixing 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
3-634f31, two facing skin materials
If only the sides are used, the amount of skin material supplied to the female mold recess will be unbalanced, and wrinkles cannot be prevented if the structure of the molded product is complex. This problem can be solved by doing so. 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.

Setting the fixing force when carrying out the method of the present invention depends on the characteristics of the abrasive, that is, the elongation of the skin material, or the structural characteristics, 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. Although it is necessary to select the optimum value, in general, it is 5·-1511k per cross-sectional area of the fixed part; / c
+o” is used.

In addition, when setting the required area of the skin A, 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 0, so as to avoid excessive quadrilateral loss. However, when both #LAj1 types are closed, -
Of course, the area must not be so small that the peripheral edge of the skin material will fall off and the fixing force will disappear.

The skin materials used in the present invention include woven fabrics, non-woven fabrics, metal 7 oils, thermoplastic resins, and thermoplastic elastomer sheets or films. A decorated material or a foamed material may also be used.

Sara tko, -ra no! ', 11. German or 2 or more types-1
It is also possible to use it in the form of a laminate in which - is laminated using a λ'i agent or the like. When these skin materials are used, they may be preheated prior to supply in order to adjust the tensile stress and elongation of the skin materials.

In addition, as the core material resin used in the present invention, I<I M
Any material commonly used in injection molding including molding and foam injection molding can be used, such as polypropylene, polyethylene styrene, acrylonitrile-styrene-butadiene block copolymer, nylon, etc. Thermoplastic tjlPIYj, thermoplastic elastomers such as ethylene-propylene block copolymers, styrene-butadiene block copolymers, thermosetting resins such as epoxy resins and phenolic resins, various vulcanized synthetic rubbers, and RIM molding. Non-foamable or foamable resins such as urethane, and those containing additives such as inorganic fillers, fillers such as glass fibers, pigments, lubricants, and antistatic agents can be used.

FIG. 2 is a sectional view showing a specific example of a molding apparatus used in the method of the present invention. In this specific example, the fixing plate (9) is
The male mold (2) is attached to the male mold (2) through a plurality of ronds (10) that protrude from the side surface toward the female mold and has a stopper (17) at the tip so that it can move forward and backward. Fixed plate (
9) is always pressed in the direction of the female mold (1) by a compression spring (18) placed between the mold and the mold. At the protruding position of the rond (10) on the side surface of the male mold (2), there is provided an annular four part (19) for storing a spring when contracted.

When carrying out method j of the present invention using the molding apparatus of this specific example, as shown in Fig. line (6)
After suctioning and holding, the female mold (1) is advanced, and the fixing plate (9) is brought into contact with the skin material (15) to fix the skin material, and after the suction is released, the mold release is further advanced. Supply hole (12
) Molten resin is injected and molded.

In this case, the fixing force of the skin material is determined by the spring constant of the compression spring (18), 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.

As described above, the method of the present invention has the following two advantages: a multilayer molded product with a good appearance without wrinkles or tears in the skin layer can be manufactured extremely economically using a simple work process. I can do it.

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 suction area of the skin material was attached to a female mold using an adhesive tape to make it non-air permeable, and the periphery of the skin material was held in the female mold by pulling 111i. Next, operate the pneumatic cylinder to move the fixing plate and apply 30 kg/a around the skin material.
It was fixed with a pressure of 1.5 m''.

After releasing the suction, close both the male and female molds and increase the resin temperature to 2 from the supply hole.
A molten resin at 30° C. was supplied to the skin material and the opening of the male mold, and the skin material and the core material were integrally molded. As a result, a good multilayer molded product without wrinkles, tears, or crushing of the foam layer was obtained. The materials and products used are as follows.

Skin material 1.5mm thick, polyester non-woven fabric with tensile elongation 45% core resin melt 70-index 151? /10 minutes (230
℃72゜16kgMm> Ethylene-Propylene Brothol Copolymer (1it Tomo/-Brenno\Y564, Sumima Kagaku) manufactured by Nigyo Co., Ltd. Molded product shape length 1 G + l m + n x width 16 (L mm x height 7)
Comparative Example 1 (111n x thickness 31+1III box shape, each vertex and side forming an arc with a radius of 5++ m) Using the same skin material and core resin as in the example, the molding apparatus used in the example (1 A multilayer molded product was manufactured using the equipment shown in Figure) except for the skin material fixing mechanism.The four sides around the skin material were completely fixed to the opposite surface of mold 11 of the female mold using double-sided tape so that it would not move. Supplying molten resin and integrating the skin layer and core material under the same fabrication and conditions as in the example,
A molded article having the same shape as in the example was obtained. The skin layer of the obtained molded article had large cracks at each vertex and each side of the bottom.

Comparative Example 2 Molding was carried out in the same manner as in Comparative Example 1, i; j, except that only two opposing sides of the four peripheral sides of the skin material were fixed to the upper male mold facing surface of the female mold with double-sided tape. In the skin layer of the obtained molded article, cracks were generated, although they were smaller than in Comparative Example 1, and large wrinkles were generated at each bottom apex and two unfixed sides.

[Brief explanation of the drawing]

Figures 1 (a) to (d) are schematic explanatory diagrams showing a cross section when a multilayer molded product is produced by a specific example of the apparatus used in the method of the present invention, and Figure 2 is a cross section of a simple example of a pond. FIG. The main symbols in the figure are as follows. 1: Female mold, 2: Male mold, 4: Recessed part, 6: Suction line, 8: Opening, 9: Fixing plate, 1'1: Molten resin, 12: Supply hole, 13: Convex part, 15: Skin material. Patent Applicant: Sumitomo Chemical Co., Ltd. Patent Attorney 1 Tun Aoyama 2 persons Figure 1 (0) Figure 1 (b) Figure 1 (C
) Figure 1 (d) Figure 2

Claims (1)

[Scope of Claims] (1) The skin material fixing plate is movably attached to the female mold or the male mold of a molding device consisting of a female mold and a male mold, and has an opening through which the convex part of the male mold passes. After sandwiching the periphery of the skin material between the fixing plate and the female mold, the female mold and the male mold are closed to squeeze the skin material into the female mold for pre-shaping, and then the skin material and the female mold or male mold are squeezed. A method for manufacturing a multilayer molded product comprising a skin and a core resin, characterized by supplying a core molten resin between the mold and the mold. (2) The skin material is fixed to the male mold facing surface around the female mold recess by a suction mechanism, and then the skin material fixing plate which is movably taken out relative to the female mold is moved, and the skin material fixing plate is moved between the fixing plate and the male die. The manufacturing method according to item (1) above, wherein the peripheral edge of the skin material is held between the female mold and the female mold. (3) The skin material is fixed to the surface facing the male mold around the female mold recess by a suction mechanism, and then it is movably removed from the male mold (= 1) The skin material is placed between the cut skin material fixing plate and the female mold. The manufacturing method according to item (1) of item i''+ij, in which the peripheral edge of the material is clamped. A manufacturing method according to any one of items (1) to (3) above. (5) Items (1) to (3) of item 1iii, wherein the means for pressing the skin material fixing plate into the female mold is a spring. 1-] Manufacturing method.