JPH0577264A - Manufacture of multi-layer molded product - Google Patents

Abstract

PURPOSE:To form a good appearance without crease, breakage or the like of the title product by molding it while retaining the periphery of a skin material by means of a pin installed on a skin material retaining frame sliding around the outer periphery of a top force or a bottom force. CONSTITUTION:A skin material 7 is stuck by a pin 5 installed on a skin material retaining frame 4 and retained thereon, and a bottom force is lifted up and the skin material retaining frame 4 is brought into contact with a top force 1 through the skin material 7. When a bottom force 2 is lifted up, an expandable device 6 is contracted by the lifting force of the bottom force, and the side face of top force is brought into contact with the side face of bottom force through the skin material 7 to form a closed cavity. When the bottom force is further lifted up and the lower plane of top force and the lower plane of bottom force form a cavity clearance of 50mm, molten resin prepared by heat melting thermoplastic resin is started to be fed into a mold through a resin path 3 formed in the top force, and the feeding is completed when the clearance is approximately 20mm. Thus a multi-layer molded product of good appearance without crease, breakage or the like on its skin material can be manufactured economically at a high cycle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a multilayer molded article in which various skin materials are laminated on the surface of a core material layer made of a thermoplastic resin.

[0002]

2. Description of the Related Art Plastic molded products are used in large quantities in various fields including automobiles and home appliances because of their economical efficiency, free shapeability and light weight. However, on the other hand, there are drawbacks such as cheapness, cold feeling, and easy scratching, and there has been a strong demand for imparting decorativeness and softness. Conventionally, various studies have been conducted in order to obtain a compound having a function that satisfies these demands.However, the improved surface texture of the above-mentioned defects can be obtained while maintaining the free formability and strength with a single material. It is difficult to have, and at present, a multilayer molded product in which a plurality of materials having different functions are combined is generally used.

There are many known methods for producing these multi-layer molded articles, for example, Japanese Patent Application Laid-Open No. 51-1.
As proposed in Japanese Patent No. 3859, there is a method of preforming a skin material by means of thermoforming or the like, placing this in a mold, and then injecting and integrating a core resin. But,
In this method, the number of working steps and the number of devices are increased, and each device and the molding method have their own technical problems, and a lot of labor and cost are required until a final product is obtained.

Another method is as follows.
As proposed in Japanese Patent Publication No. 132, there is a method of manufacturing using a device provided with a vacuum molding function and a core material resin injection function in a single mold, but basically it is not the former area.

Further, as a method of overcoming the drawbacks of the above-mentioned two methods, a non-preformed skin material is placed in a mold and a core material is proposed, as proposed in JP-A-53-63461. A method of integrating with a resin has been proposed. Although this method is economical, tension control is in one direction and tension control in the other direction is not possible, so wrinkles occur and it is difficult to obtain a molded product with a deep three-dimensional drawing. There is a limit in that you can obtain only those shapes.

Further, as proposed in Japanese Patent Publication No. 63-24807, the peripheral edge of the skin material is sandwiched between the skin material fixing frame and the female die, and the skin material is preliminarily shaped. There is a method for producing a multi-layer molded product in which a resin is melted and supplied for molding, but it is not always possible to obtain a satisfactory result for a large molded product, especially when the shape is complicated.

[0007]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the drawbacks of these conventional methods, and particularly in the case of a molded product having a complicated shape, the surface material of the molded product is free from wrinkles and tears. It is an object of the present invention to provide an extremely economical method for producing a multi-layer molded article which gives a unique appearance and has a simplified working process.

[0008]

Means for Solving the Problems The inventors of the present invention have made extensive studies in view of the above-mentioned problems, and as a result, carry out compression molding while holding the peripheral edge of the skin material with pins, whereby a multilayer molded article having an extremely good appearance is obtained. The present invention has been completed and the present invention has been completed. That is, the present invention supplies a skin material and a thermoplastic resin between a pair of upper and lower molds, pressurizes and cools to form a multilayer molded article in which the skin material is pasted on the surface of the thermoplastic resin core material layer. In doing so, the method for producing a multilayer molded article is characterized in that molding is performed while holding the peripheral edge of the skin material with pins provided on the skin material holding frame that slides on the outer periphery of the upper mold or the lower mold.

As the skin material used in the present invention, a woven fabric, a non-woven fabric, a thermoplastic resin such as polyolefin, vinyl chloride, nylon or the like, or a sheet of a thermoplastic elastomer such as polyolefin, polyester, urethane or vinyl chloride, or Examples include films. It is also possible to use one of these sheets or films or a laminate of two or more of them as a skin material. In order to give a softer touch, a foam sheet made of polypropylene, polyethylene, urethane, etc. is attached to the back of the skin material, or it is protected from the heat of the molten resin during molding, and the skin material and core material layer are It is also possible to use a cloth, a sheet or the like which is attached to the back surface for the purpose of strengthening the adhesive force. When using these skin materials, preheating may be performed prior to the supply in order to adjust the tensile stress and elongation of the skin material.

As the thermoplastic resin used as the core material layer in the present invention, any of those usually used in compression molding, injection molding and extrusion molding can be used. For example, polypropylene, polyethylene, polystyrene, acrylonitrile- Examples thereof include styrene-butadiene copolymers, thermoplastic resins such as nylon, and thermoplastic elastomers such as ethylene-propylene block copolymers and styrene-butadiene block copolymers. Further, those containing an additive such as an inorganic filler, a filler pigment such as glass fiber, a lubricant, an antistatic agent or the like can be appropriately used.

In the present invention, a skin material holding frame which slides on the outer periphery of the upper die or the lower die is provided, and a large number of pins are provided on the surface thereof. It is preferable to provide the pin having a diameter of 3 to 6 mm so as to vertically project about 20 mm from the surface of the skin material holding frame.

The skin material holding frame has an upper or lower mold, a spring,
Although it is attached via an expansion / contraction device having an expansion / contraction function such as an air cylinder or a hydraulic cylinder, the skin material holding frame may be fixedly attached to the expansion / contraction device or may be easily removable from the expansion / contraction device. In the case of removable skin material holding frames, it is possible to prepare a plurality of them and set the skin material on the other skin material holding frame during molding of one molded body to prepare for the next molding. It is effective for improving the molding cycle.

In the present invention, the skin material is covered with the skin material by piercing the peripheral edge of the skin material with a pin provided in the skin material holding frame, or by passing the pin through a hole previously formed at a predetermined position of the skin material peripheral edge. Can be set on the holding frame. In this way, the mold is closed while the peripheral edge of the skin material is held, and the thermoplastic resin is compression-molded to obtain a multi-layer molded product having the skin material bonded to the surface thereof. At the time of this molding, the diameter of the skin material holding frame and the installation density are set on the assumption that the skin material that is tensioned and held by the pin is cut by the pin from the pin position toward the center of the mold. The amount of sliding of the skin material into the mold is adjusted by adjusting and partially controlling the holding power of the skin material. When pins with the same diameter are used, the holding force of the skin material is large at places where the pins are installed at a high density, and the slipping amount of the skin material becomes small. ..

For example, when a skin material is attached to the entire surface of a box-shaped molded product, wrinkles are easily formed on the skin material at the rising portions of each corner. It is advisable to provide them to increase the holding force at the peripheral edge of the skin material. Also, the skin material may break during molding,
If it is stretched excessively, attach it to the pin on the skin material holding frame with the skin material slightly slackened in advance and allowing it.

When a pin having a large diameter is used, the holding force of the skin material is larger than that of a pin having a small diameter, and therefore the amount of slipping of the skin material becomes smaller. Therefore, the amount of slipping can be adjusted by the diameter of the pin. It is possible.

Since the skin material of the portion held by the pin is cut toward the center of the mold, the end of the molded product to be the product is prevented so that the cut of the skin material is not stuck to the surface of the molded product. It is preferable to provide a pin outside the position corresponding to the mold by 10 mm or more. In addition, the pin diameter is 3 to 3 due to workability when setting the skin material in the skin holding frame and durability of the pin.
It is preferably 6 mm.

The molten resin in the present invention may be supplied by a molten resin supply device provided outside the mold,
A method of supplying through a resin passage provided in the upper or lower mold is more preferable. In this case, the supply of molten resin is usually
The mold clamping speed is set to 30 mm / sec or less, and the upper and lower mold clearances are set between (C + 5) to (C + 100) mm (where C represents the clearance at the time of completion of shaping). Further, the mold is clamped until the clearance reaches C mm, and the desired multilayer molded article is obtained by pressurizing and cooling for a predetermined time.

[0018]

The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

Example 1 An example of molding using a molding machine shown in FIG. 1 with a mold for molding a molded article shown in FIG. 3 attached to a press having a mold clamping force of 400 tons will be described below. As shown in FIG. 2, pins having a length of 5 mm and a length of 20 mm are provided on the skin material holding frame at intervals of 230 mm on each side of the holding frame, and at intervals of 50 mm at each corner of the holding frame. ..

The skin material is a textured vinyl chloride sheet backed by an elastic cloth and has a thickness of 0.7 mm (manufactured by Kyowa Leather Co., Ltd.). The thermoplastic resin is polypropylene with 15% talc added. (Sumitomo Chemical Co., Ltd., Sumitomo Noblen BPZ5077, melt flow index 40 g / 10 minutes) is used to set the temperature of the upper mold and the lower mold to 50 ° C. and 60 ° C., respectively.

The skin material (7) is pierced and held by the pin (5) provided on the skin material holding frame (4), and the lower mold is raised.
The skin material holding frame (4) and the upper mold (1) are brought into contact with each other via the skin material (7). When the lower mold (2) is further raised, the expansion device (6) contracts due to the lifting force of the lower mold, and the side surface of the upper mold and the side surface of the lower mold are in contact with each other via the skin material (7) and closed. To form a cavity.

When the lower die is further raised and the cavity clearance between the lower plane of the upper die and the plane of the lower die is 50 mm, the rate of raising the lower die is set to 7 mm / sec and the above thermoplastic resin is added. The molten resin heated and melted at 220 ° C. is started to be supplied into the mold through the resin passage (3) provided in the upper mold, and the supply is completed when the clearance is 20 mm. When the lower mold (2) is further raised, the molten resin is pressurized and flows to the end of the cavity while pressing the skin material (7) against the lower mold surface and stretching the skin material (7). Filled inside.

When the clearance reaches 3.1 mm, the skin material holding frame (4) comes into contact with the horizontal portion of the upper mold and the lower mold (2) stops rising. After pressurizing and cooling (40 seconds) for a predetermined time in this state, the lower mold (2) was lowered to take out the target molded product, and the surface was covered with beautiful wrinkles without wrinkles or tears. A molded product having a core layer thickness of 2.5 mm is obtained.

Example 2 A mold for molding a molded product shown in FIG. 3 is attached to a press having a mold clamping force of 400 tons, and the molding apparatus shown in FIG. 4 is used. As shown in FIG. 5, the skin material holding frame has 5 mmφ, 2
Pins of 0 mm length are provided on each side of the holding frame at intervals of 230 mm, pins are provided at intervals of 50 mm at each corner of the holding frame, and a bar transmission hole (11) is provided at the center of each side. ) Is provided.

The surface material is embossed and has a thickness of 0.5.
A 3.0 mm thick foamed polypropylene (Toray Industries, Inc., foaming ratio 15 times) is attached to the back side of a vinyl chloride sheet of mm, and the talc 15 is used as the thermoplastic resin.
% Polypropylene (Sumitomo Chemical Co., Ltd., Sumitomo Noblen BPZ5077, melt flow index 40 g / 10 min) is used to set the temperature of the upper mold and the lower mold to 20 ° C. and 30 ° C., respectively.

The skin material (7) is pierced and held by the pin (5) provided on the skin material holding frame (4), and the upper mold (1) is lowered to make the skin material holding frame (4) and the upper mold. (1) and abut. When the upper mold (1) is further lowered, the expansion device (6)
Contracts due to the lowering force of the upper mold, and the side surface of the upper mold and the side surface of the lower mold are in contact with each other via the skin material (7) to form a closed cavity.

When the upper die (1) is further lowered, the cavity clearance between the lower plane of the upper die and the plane of the lower die is 50 mm.
Then, set the upper mold lowering speed to 7 mm / sec,
The molten resin obtained by heating and melting the thermoplastic resin at 190 ° C. is supplied into the mold cavity through the resin passage (3) provided in the lower mold, and the cavity clearance is 20.
Supply is completed when mm. When the upper mold (1) is further lowered, the molten resin is pressurized and flows to the end of the cavity while pressing the skin material (7) against the upper mold surface and stretching the skin material (7). Filled inside.

When the clearance reaches 2.7 mm, the skin material holding frame (4) comes into contact with the horizontal portion of the lower mold, and the lowering of the upper mold (1) is stopped. After pressurizing and cooling (40 seconds) for a predetermined time in this state, the upper mold (1) was raised to take out the target molded product, and the surface was free from wrinkles and tears and covered with beautiful wrinkles. A molded product having a core layer thickness of 2.0 mm is obtained.

By preparing a plurality of skin material holding frames, setting the skin material in advance, and subjecting them sequentially to molding, it becomes possible to perform molding in a very high cycle.

[0030]

EFFECTS OF THE INVENTION According to the present invention, it is possible to economically produce a multi-layered molded product having a good appearance without wrinkles or tears on the surface material of the molded product in a high cycle with a simple device. It can be manufactured.

[0031]

[Brief description of drawings]

FIG. 1 is a vertical plan view of an apparatus used in Example 1 of the present invention.

FIG. 2 is a plan view of a skin material holding frame used in Example 1 of the present invention.

FIG. 3 is a perspective view of a multi-layer molded product molded in the embodiment of the present invention.

FIG. 4 is a vertical sectional view of an apparatus used in Example 2 of the present invention.

FIG. 5 is a plan view of a skin material holding frame used in Example 2 of the present invention.

[Explanation of symbols]

 (1) Upper mold (2) Lower mold (3) Resin passage (4) Skin material holding frame (5) Pin (6) Stretching device (7) Skin material (8) Molten resin (9) Bar (10) Spring (11) Bar transmission hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeyoshi Matsubara 2-10-1 Tsukahara, Takatsuki City, Osaka Sumitomo Chemical Co., Ltd.

Claims (2)

[Claims] 1. A multi-layer molded product in which a skin material and a thermoplastic resin are supplied between a pair of upper and lower molds, and the surface and the skin material are laminated on the surface of a thermoplastic resin core material layer by pressurizing and cooling. At this time, the method for producing a multilayer molded article is characterized in that molding is performed while holding the peripheral edge of the skin material with a pin provided in a skin material holding frame that slides on the outer periphery of the upper mold or the lower mold. 2. A multilayer molded article obtained by the method of claim 1.