JPH0386527A - Simultaneous molding method with different kind of raw materials - Google Patents

Abstract

PURPOSE:To reduce the cost of a foamed molded body by certainly performing the mutual division filling of a different kind of raw materials. CONSTITUTION:At first, a vacuum pump 10 is operated to reduce the pressure in a cavity part 3. The shutter valve 24 connected to the cavity part 3 is opened to send air to the cavity part 3 from an air lead-out part 14. By this method, a raw material having foaming magnification of 30 times is sucked by vacuum suction force to fill the lower part 3a of the cavity part 3. After the completion of the filling to the lower part 3a, filling operation in once interrupted to perform cracking operation opening a core mold 1 and a cavity mold 2 by several mm to separate both of them. The cavity part 3 is formed by clamping can be cavity part 3 is filled with many kinds of raw materials having a foaming magnification of 55 times stored in the second hopper 27. Subsequently, the core mold 1 and the cavity mold 2 are heated by steam having predetermined pressure and finally heated to expand the raw materials to fuse the same. Further, forcible cooling is performed and the molded product is taken out of the cavity part 3.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of simultaneous molding using different raw materials, and involves mixing the respective raw materials by using different raw materials made of two or more types of expandable thermoplastic resin particles. It is designed so that it can be molded and fused into one piece.

[Conventional technology]

Foamed molded products are sometimes used as packaging materials for products or structural materials for buildings, and depending on the use, special functions such as high strength and chemical resistance may be required. In some cases, this special function is required for the entire foamed molded product, but in many cases, it is only necessary to satisfy it partially. Furthermore, the expandable thermoplastic resin particles having this special function are often more expensive than the general expandable thermoplastic resin particles.

Therefore, when molding a foam molded product that partially requires the above-mentioned functions, foamable thermoplastic resin particles with special functions are usually used only in the necessary parts, and general resin particles are used in other parts. Expandable thermoplastic resin particles are used. As a result, the cost of the foamed molded product can be reduced while still having fully satisfactory functions.

In general, the above-mentioned foam molded products are formed by simultaneously molding different types of raw materials, which are a plurality of types of expandable thermoplastic resin particles having special or general functions. and,
As a method for performing this simultaneous molding, for example,
As disclosed in Japanese Patent Publication No. 55896 and Japanese Patent Publication No. 5B-29728, parts filled with different types of raw materials are divided by partition plates or partition pins inserted into the cavity, which is the space formed by the cavity and the core. There is a known method in which separate parts are filled with each raw material.

[Problem to be solved by the invention]

However, the above simultaneous molding method requires a driving means to insert and remove the partition plate and partition pin into the cavity, or requires special processing on the cavity and core. Processing has tended to increase the cost and complexity of equipment.

Therefore, for example, Japanese Patent Publication No. 61-9136 and Japanese Patent Publication No. 61-9136,
Japanese Patent No. 1-58292 discloses a method of press-fitting air together with raw materials into a cavity at a time difference without using the above-mentioned partition plates or partition pins. As a result, the structure of the device is simplified and costs can be reduced.

However, in this method, the raw material filled in the cavity becomes suspended by the air press-injected near the interface where it comes into contact with a different type of raw material. This floating causes different types of raw materials to mix with each other near the interface, which is an obstacle to reliable divided filling. This unreliable divided filling makes it difficult to sufficiently control the supply of raw materials to the cavity.

For example, when forming a foam molded product by combining a raw material with a low expansion ratio and a raw material with a high expansion ratio, the raw material with a low expansion ratio requires a larger amount compared to the raw material with a high expansion ratio, so foam molding This is a factor contributing to the high cost of products. Therefore, in order to reduce the cost of foam molded products, it is necessary to accurately fill only the necessary parts with the above-mentioned low expansion ratio raw material.

However, with the above-mentioned method, it is difficult to accurately fill only the necessary portions of the foamed molded product with the raw material having a low expansion ratio. Therefore, the foam molded product is filled with a raw material having a low expansion ratio in an amount larger than necessary in order to satisfy the required quality of the foam molded product, resulting in an increase in cost.

Therefore, in the present invention, a method of simultaneous molding using different raw materials is capable of configuring an apparatus at low cost with a simplified structure, and reducing the cost of foam molded products by reliably dividing and filling different raw materials. is intended to provide.

[Means to solve the problem]

In order to solve the above problem, the simultaneous molding method using different raw materials according to the invention of claim 1 includes disposing different raw materials made of a plurality of types of expandable thermoplastic resin particles in a cavity portion formed by a core and a cavity. In the method of forming a foam molded product by filling each material separately and heating and expanding these different types of raw materials with a heating medium such as steam, a vacuum suction means connected to the core and the cavity is operated to reduce the pressure in the cavity. , fill the raw material into the specific section of the foam molded product using vacuum suction power, and introduce air into the cavity other than the section, and then temporarily interrupt the filling operation. A cracking operation is performed to separate the core and the cavity, and then mold clamping is performed to connect the core and the cavity again to form a cavity part, and a raw material of a different type than the above raw material is added to the cavity part other than the partitioned part. It is characterized by being filled with compressed air to form a foamed molded product.

In order to solve the above problem, the simultaneous molding method using different raw materials according to the invention of claim 2 includes disposing different raw materials made of a plurality of types of expandable thermoplastic resin particles in a cavity portion formed by a core and a cavity. In the method of forming a foam molded product by filling each material separately and heating and expanding these different types of raw materials with a heating medium such as steam, a vacuum suction means connected to the core and the cavity is operated to reduce the pressure in the cavity. , fill the raw material into the specific section of the foam molded product using vacuum suction power, and introduce air into the cavity other than the section, and then temporarily interrupt the filling operation. A cracking operation is performed to separate the core and the cavity, and then mold clamping is performed to connect the core and the cavity again to form a cavity section, and a raw material of a different type than the above-mentioned raw material is placed in the cavity section other than the partitioned section under vacuum. It is characterized in that it is filled with pressurized air using suction power to form a foamed molded product.

[Function] According to the structures of claims 1 and 2, the pressure in the cavity is reduced by the vacuum suction means, and the raw material is drawn into the partitioned portion of the cavity by the vacuum suction force caused by the above-mentioned reduced pressure. It will be filled.

At this time, the above-mentioned raw material does not enter the cavity portion other than the partitioned portion because pressurized air is fed into the cavity portion other than the partitioned portion.

In this state, the raw material filled in the above-mentioned cavity part has a large unevenness at the interface where it contacts other types of raw materials and is not smooth, but once it is filled, By interrupting the filling operation and performing a cracking operation to separate the core and cavity, the interface becomes smooth.

After this, after the mold is clamped again and the cavity is formed, in the case of claim 1, a different type of raw material from this raw material is poured into the cavity other than the partitioned part together with pressurized air. Filled. Further, in the case of claim 2, a material different from the above-mentioned materials is filled into the cavity portion other than the partitioned portion together with pressurized air using vacuum suction force. As a result, the raw material filled in the partitioned portion is prevented from floating near the interface by the pressurized air.

Therefore, different types of raw materials do not mix with each other,
Reliable split filling becomes possible. Furthermore, preventing the raw material from floating near the interface makes it easier to control the supply amount when filling the raw material, which in turn makes it possible to reduce the cost of the foam molded product.

Further, the pressure in the partitioned portion is reduced by a vacuum suction means connected to the core and the cavity. Therefore, since this device does not require special equipment or processing for dividing the partitioned portions, the structure is simplified and can be constructed at a very low cost.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

The simultaneous molding method using different raw materials according to this embodiment has a core mold 1 and a cavity mold 2, as shown in FIG. A cavity portion 3 is formed.

The core mold 1 and the cavity mold 2 described above are formed hollow inside, and steam piping and cooling water piping (not shown) are disposed in the hollow interior.

In addition, a vacuum pump 10 is provided on the outer wall of the core mold 1 and the cavity mold 2 via vacuum pipes 4, 4, while a large number of steam holes (not shown) are formed on the inner wall 1a, 2a on the side of the cavity part 3. ing.

Thereby, the cavity part 3 is connected to the vacuum pump 10 described above.
The pressure is reduced through vacuum pipes 4, 4 and steam holes. Incidentally, the vacuum suction means is composed of the vacuum pipes 4, 4 and the vacuum pump IO described above.

Further, the inner wall 2a of the cavity mold 2 is provided with filling pipes 11a and 12a for introducing raw material made of expandable thermoplastic resin particles such as polystyrene into the cavity portion 3. The expandable thermoplastic resin particles described above are not limited to polystyrene, and may be, for example, polyethylene, polypropylene, or any other type of thermoplastic resin particles used in foam molding.

The above-mentioned filling pipes 11a and 12a are disposed in the upper part of the cavity mold 2 and in the lower part corresponding to the partitioned part of the foam molded product, which is a specific part having low expansion ratio or chemical resistance, for example. It is provided by penetrating the outer wall from inside the hollow of 2. These filling pipes 11a and 12a include
Air outlet portions 14 and 15 introduce air with a predetermined pressure into the filling pipes 11a and 12a, and feed raw materials into the filling pipes 11a and 12a.
The feeder 11 is formed with foamed grain outlet parts 17 and 18 to be introduced into the cavity part 12a, and has built-in pistons 28 and 29 that can move forward and backward in the direction of the cavity part 3.
12 are provided. And filling pipe 11a-12
A is closed by the forward movement of the pistons 28 and 29, and opened by the backward movement of the pistons 28 and 29.

In addition, exit hoses 20 and 21 are provided in the foamed grain outlet portions 17 and 18, respectively. These school discharge hoses 20
・Among the 21, the foamed grain outlet part 18 is installed in the lower filling pipe 12a.
The discharge hose 21 provided through the first tube is connected to the first discharge hose 21, which is filled with raw material, which is foamable thermoplastic resin particles having an expansion ratio of 30 times, for example, through a shutter valve 24 that can be opened and closed.
It is connected to the hopper 25.

On the other hand, the foamed grain outlet section 17 formed in the upper filling pipe 11a is connected to a second hopper 27 arranged in parallel with the first hopper 25 via an exit hose 20 and a freely openable/closable navigator valve 26. . The second hopper 27 is filled with a raw material that is expandable thermoplastic resin particles having an expansion ratio of, for example, 55 times.

In the above configuration, as shown in FIG.
Procedures for molding the cushioning packaging material 31, which is a foam molded product that fits into the end of an electrical product, etc., and is used for protection during transportation and storage, with the upper part 31b having a low foaming ratio and the upper part 31b having a high foaming ratio. is shown below.

First, as shown in FIG. 1, the vacuum pump 10 is operated to reduce the pressure in the cavity 3. At the same time, piston 2
8. Retract the two and open the filling pipes 11a and 12a. After that, the shutter valve 24 of the first hopper 25 connected to the filling pipe 12a corresponding to the lower part 3a of the cavity part 3 is opened, and the air outlet part formed in the filling pipe 11a other than the above-mentioned filling pipe 12a is opened. From 14,
Air of about 1112 g/l is sent to the cavity part 3 from 1 to 6. As a result, the raw material having an expansion ratio of 30 times is sucked by the vacuum suction force generated by the reduced pressure in the cavity part 3, and is filled into the lower part 3a. At this time, as shown in FIG. 4, when the raw material is made into a molded product in this state, it has an uneven shape at the interface between the lower part 3a and the upper part 3b. The air sent out to the upper part 3b does not enter from the lower part 3a.

When the filling into the lower part 3a is completed, the above-mentioned filling operation is temporarily interrupted, and a cracking operation is performed in which the core mold 1 and the cavity mold 2 are opened several times and separated. This results in
The above-mentioned uneven interface becomes smooth as shown in FIG. Then, as shown in Fig. 2, the core mold 1 is
The cavity mold 2 is connected and closed to form the cavity part 3, the shutter valve 26 of the second hopper 27 is opened, and the suction force of the air sent from the air outlet part 14 is used to close the mold. The cavity portion 3 is filled with another type of raw material having a foaming ratio of 55 times, which is stored in the second hopper 27. Incidentally, after the mold is clamped again, in addition to the above-mentioned air blow suction force, the cavity portion 3 may be depressurized and other types of raw materials may be filled using the vacuum suction force.

After this, in addition to the above-mentioned filling pipe 11a, the air outlet part 1
5, pressurized air is sent into the filling pipe 12a. Then, the vacuum pump 10 is stopped, and the filling pipe 11a, 1
2a and the raw materials remaining in the exit hoses 20 and 21 are blown back into the first hopper 25 and second hopper 27, and the pistons 28 and 29 are advanced to fill the filling pipe 11a12.
Close a.

Next, the inside of the core mold 1 and the inside of the cavity mold 2 are heated with steam having a predetermined pressure, and then main heating is performed to thermally expand and fuse. Furthermore, by performing forced cooling with cooling water, allowing the product to cool, and then taking it out from the cavity portion 3, the foamed molded product shown in FIG. 3 can be obtained.

A foamed molded article formed by such a method has extremely little mixing of raw materials having different expansion ratios. That is, as shown in FIG. 1, the raw material filled in the lower part 3a is prevented from floating near the interface where it comes into contact with other types of raw materials due to the pressure of the pressurized air.
It does not mix with other types of raw materials. Furthermore, the above-mentioned raw material has become smooth because the unevenness at the interface is removed by a cracking operation.

Therefore, when a foamed molded product is formed using this method, it becomes possible to accurately divide and fill the raw material only into the necessary parts of the foamed molded product, and it is possible to use raw materials with a low expansion ratio that would otherwise lead to high costs. Since there is no need for excessive filling, it is possible to reduce the cost of the foam molded product.

Further, the pressure in the cavity part 3 can be reduced by providing a vacuum pump 10 between the core mold 1 and the cavity mold 2 via vacuum piping 4, and activating this vacuum pump IO to draw air from the steam hole. It has become. Therefore, the device according to the method of this embodiment requires only slight changes to the existing device, for example, there is no need for a drive device for partitioning or special processing, and the device itself can be improved by simplifying the structure. It is possible to construct it at a very low cost.

In this embodiment, the apparatus is used for filling two types of raw materials, but the apparatus is not limited to this, and may be an apparatus capable of filling three or more types of raw materials.

〔Effect of the invention〕

As described above, the method for simultaneous molding using different raw materials according to the invention of claim 1 divides different raw materials each consisting of a plurality of types of expandable thermoplastic resin particles into the cavity portion formed by the core and the cavity. In the method of forming a foamed molded product by heating and expanding these different raw materials with a heating medium such as steam, a vacuum suction means connected to the core and the cavity is operated to reduce the pressure in the cavity, and the foam molding is performed. The raw material is filled using vacuum suction power into the compartments that are specific parts of the product, and air is introduced into the cavity other than the compartments, and then the filling operation is temporarily interrupted and the core and cavity are filled. A cracking operation is performed to separate the core and the cavity, and then mold clamping is performed to connect the core and the cavity again to form a cavity part, and 0 kinds of raw materials different from the above raw materials are pressurized into the cavity part other than the partitioned part. The structure is such that a foam molded product is formed by filling the foam with air.

This prevents the raw materials filled in the compartment from floating near the interface, making it possible to prevent different types of raw materials from mixing with each other, and also making it possible to reliably divide and fill the raw materials by preventing them from floating. This eliminates the need for excessive filling of raw materials that would lead to high costs, making it possible to reduce the cost of foam molded products.

Furthermore, since the vacuum suction means can reduce the pressure in the compartments to enable reliable divisional filling of different raw materials, it is possible to construct the apparatus at a very low cost.

As described above, the method for simultaneous molding using different raw materials according to the invention of claim 2 divides different raw materials each consisting of a plurality of types of expandable thermoplastic resin particles into the cavity portion formed by the core and the cavity. In the method of forming a foamed molded product by heating and expanding these different raw materials with a heating medium such as steam, a vacuum suction means connected to the core and the cavity is operated to reduce the pressure in the cavity, and the foam molding is performed. The raw material is filled using vacuum suction power into the compartments that are specific parts of the product, and air is introduced into the cavity other than the compartments, and then the filling operation is temporarily interrupted and the core and cavity are filled. A cracking operation is performed to separate the core and the cavity, and then mold clamping is performed to connect the core and the cavity again to form a cavity part, and a vacuum suction force is applied to the cavity part other than the partitioned part to draw a different type of raw material from the above raw material. The structure is such that a foam molded product is formed by filling the foam with pressurized air.

This prevents the raw materials filled in the partitioned portions from floating near the interface, making it possible to prevent different types of raw materials from mixing with each other. In addition, since it is possible to reliably fill the foam in parts by preventing the raw material from floating, there is no need to overfill the raw material, which would lead to high costs, and it is possible to reduce the cost of the foam molded product.

Furthermore, since the vacuum suction means can reduce the pressure in the compartments to enable reliable divisional filling of different raw materials, it is possible to construct the apparatus at a very low cost.

[Brief explanation of drawings]

1 to 4 show embodiments of the present invention. FIG. 1 is a cross-sectional structural diagram of a molding apparatus showing a state filled with raw materials, which are expandable thermoplastic resin particles with a low expansion ratio. FIG. 2 is a cross-sectional structural diagram of the molding apparatus showing a state filled with raw materials, which are expandable thermoplastic resin particles with a high expansion ratio. FIG. 3 is a perspective view of the foam molded product. FIG. 4 is a perspective view of a foam molded product with an uneven interface. 1 is a core type, 2 is a cavity type, 3 is a cavity part, 4
10 is a vacuum pipe (vacuum suction means), 10 is a vacuum pump (vacuum suction means), 11 and 12 are feeders, 14 and 15 are air outlet parts, 17 and 18 are foamed grain outlet parts, and 20 and 21 are discharge hoses.

Claims (1)

[Claims] 1. A cavity formed by a core and a cavity is filled with different raw materials made of a plurality of types of expandable thermoplastic resin particles, and these different raw materials are heated by a heating medium such as steam. In the method of forming a foamed molded product by heating and expanding, a vacuum suction means connected to the core and the cavity is activated to reduce the pressure in the cavity, and the vacuum suction force is applied to a specific section of the foamed molded product. At the same time, air is introduced into the cavity other than the partitioned portions, and then the filling operation is temporarily interrupted and a cracking operation is performed to separate the core and the cavity, and then the core and the cavity are separated again. A mold clamping is performed to connect the mold to the cavity to form a cavity part, and a raw material of a different type from the above raw material is filled into the cavity part other than the partitioned part with pressurized air to form a foamed molded product. A simultaneous molding method using different raw materials. 2. The cavity formed by the core and the cavity is filled with different types of raw materials consisting of a plurality of types of expandable thermoplastic resin particles, and these different types of raw materials are heated and expanded using a heating medium such as steam to form foam molding. In the method of forming the product, a vacuum suction means connected to the core and the cavity is operated to reduce the pressure in the cavity, and the vacuum suction force is used to fill the raw material into the partitioned portion that is a specific part of the foam molded product. At the same time, air is introduced into the cavity part other than the partitioned part, after which the filling operation is temporarily interrupted and a cracking operation is performed to separate the core and the cavity, and then the core and the cavity are connected again. A cavity is formed by tightening the mold, and a raw material of a different type from the raw materials mentioned above is filled into the cavity other than the partitioned parts together with pressurized air using vacuum suction force to form a foamed molded product. Features: Simultaneous molding method using different raw materials.