JPH0577331A - Molding method for foam synthetic resin molded article - Google Patents

Abstract

PURPOSE:To enable homogenous moldings to be molded easily from two or more different kinds of raw material particles to solve or lessen problems encountered by foam synthetic resin moldings molded from a kind of raw material particles. CONSTITUTION:Moldings are so molded that different kinds of raw material particles are filled into a molding space 16 defined by a pair of clamped molds 14, 15 for foam synthetic resin moldings through a single raw material filling feeder 13 from two or more kinds of hoppers 11,12 containing different kinds of raw material particles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is formed from two or more kinds of different raw material particles in order to solve or reduce the problems of a foamed synthetic resin molded article formed from a single kind of raw material particles. TECHNICAL FIELD The present invention relates to a method for molding a foamed synthetic resin molded product, which enables easy and reliable molding of a product.

[0002]

2. Description of the Related Art Since foamed synthetic resin molded products have high heat insulation performance and high cushioning performance, they have been widely used as a box for storing fresh products such as vegetables and fish, and a cushioning material for electric devices. Has been done. Such a molded product is molded, for example, from a foam molding machine whose outline is shown in FIG. In the figure, 1 is a hopper containing raw material particles, 2 is a raw material filling feeder, 3 and 4 are a pair of molding dies, and 5 is formed between the pair of molds 3 and 4 when the molds are closed. A molding space 6 and 7 are heating chambers behind the molding spaces 5 of the pair of molds 3 and 4, and a connecting pipe 8 connects the hopper 1 and the raw material filling feeder 2. Then, a single kind of raw material particles is put in the hopper 1.

By closing the pair of molds 3 and 4 as described above,
The raw material particles in the hopper 1 are filled into the molding space 5 formed between them by air feeding from the connecting pipe 8 through the raw material filling feeder 2. Then, a pair of molds 3, 4
Steam is supplied to the heating chambers 6 and 7 in the back to thermally bond the raw material particles, and then water or air is supplied to the heating chambers 6 and 7 to cool them. Then, the pair of molds 3 and 4 are opened, and the foamed synthetic resin molded product molded in a desired shape is taken out from the molding space 5.

[0004]

Naturally, such a foamed synthetic resin molded article is entirely composed of raw material particles made of the same material and having substantially the same expansion ratio. Moreover, the color is also single.

By the way, when such a molded product is a box for storing fresh products such as vegetables and fish, the printing characteristics are inferior to those of other corrugated cardboard boxes used for storing the same type, so that it looks good. There is a problem that it is difficult to improve. Further, when the raw material particles of the molded product are white, there is also a problem that the surface turns yellow when used for a long period of time or outdoors. For this reason, it is conceivable to mold the entire molded product with colored raw material particles, but there is a problem that the colored raw material particle itself is expensive and the molded product becomes expensive.

Under these circumstances, the present inventors have come to the idea of forming a molded article by mixing uncolored white raw material particles and colored raw material particles. However, FIG.
In a foam molding machine whose outline is shown in FIG. 1, it is troublesome and difficult to put the white raw material particles and the colored raw material particles in the hopper in a uniform mixture at a required ratio. Even if these raw material particles are uniformly mixed in the hopper, it cannot be said that the foaming ratio, particle size, and density of the both are almost the same, and the raw material filling feeder is fed from the hopper. When the raw material particles are filled in the molding space by air feeding by the method, only one raw material particle may be unevenly distributed, and it is difficult to mold a homogeneous molded product.

[0007]

In view of the above problems, the inventors of the present invention have earnestly studied, and as a result, have come to the present invention. Further, according to the present invention, it is possible to form a foamed synthetic resin molded article by using uncolored white raw material particles and colored raw material particles, as well as three or more different raw material particles, and two or more of the same material with a foaming ratio. It has been found that a molded article can be molded from any two or more kinds of different raw material particles such as different raw material particles or different raw material particles of two or more materials.

According to the first aspect of the present invention, a mold for molding a pair of foamed synthetic resin molded articles is closed through a single raw material filling feeder from two or more hoppers containing raw material particles of different types. A method for molding a foamed synthetic resin molded article, characterized in that a molded product is molded by filling different kinds of raw material particles into a molding space formed between them, and in Claim 2, different kinds of raw material particles are used. Through a single raw material filling feeder from two or more put hoppers, different types of raw material particles are almost uniform at the same time in the molding space formed between the molding dies of a pair of foamed synthetic resin molded products that are closed. A method for molding a foamed synthetic resin molded article is characterized in that the molded article is molded by being mixed and filled in. Further, in claim 3, raw material particles of different types are raw material particles of different colors, and in claim 4, raw material particles of different types are raw material particles of the same material but having different expansion ratios. Further, in claim 5, the raw material particles of different types are raw material particles of different materials.

[0009]

According to the molding method of such a foamed synthetic resin molded article, for example, the uncolored white raw material particles and the colored raw material particles are put in different hoppers, respectively, and the raw material particles are filled in the molding space. In the process, both are mixed to form a molded product. In addition, raw material particles of the same material but different expansion ratios, or raw material particles of different types such as raw material particles of different materials are put in different hoppers, respectively, and molded articles are molded in the same manner as described above. To do.

[0010]

EXAMPLES The details of the method for molding a foamed synthetic resin molded article according to the present invention will be further described based on the foaming molding machine.

FIG. 1 shows an outline of such a foam molding machine. In the figure, 11 is a first hopper containing a certain type of raw material particles, and 12 is a different type from the raw material particles placed in the first hopper. A second hopper containing different raw material particles, 13 is a raw material filling feeder, 14 and 15 are a pair of molding dies, and 16 is formed between the pair of molds 14 and 15 when the molds are closed. Forming space, 17 and 18 are heating chambers behind the forming space 16 side of the pair of molds 14 and 15, 19 and 20 are connecting pipes for connecting the first hopper 11, the second hopper 12 and the raw material filling feeder 13, respectively. Is a connecting pipe 20 for connecting the second hopper 12 and the raw material filling feeder 13.
It is a valve provided in the middle of. The mold 15 not provided with the raw material filling feeder 13 is provided laterally movable with respect to the other molds 14. In this pair of molds 14 and 15, steam pipes for supplying steam to the respective heating chambers 17 and 18,
A water pipe or an air pipe for supplying water or air to the heating chambers 17 and 18 to cool it, a drain pipe for drainage, and a mold 14 side provided with the raw material filling feeder 2 for separating a molded product from the molding space 16 A mold pin is provided, but it is not shown.

Next, FIG. 2 shows a raw material filling feeder. The raw material-filled feeder 13 has a cylindrical body 22 having a distal end side which penetrates one of the molds 14 from the outside to allow the internal space 23 of the main body 22 to be seen in the molding space 16 and which is formed on the outer periphery of the main body 22. The mounting flange 24 provided is brought into contact with and attached to the outside of the mold 14, and a cylinder 25 is provided on the base end side of the main body 22. The internal space 23 of the main body 22 is used as a flow path 26 for raw material particles, and the piston rod 28 provided with the piston 27 of the cylinder 25 also has this space.
It is also used as a sliding space for the piston 27 as viewed through 23. In the figure, reference numeral 29 denotes a first inflow portion for raw material particles which is integrally provided in the main body 22 so as to communicate with the base end side of the internal space 23 of the main body 22. It is in communication with the inside of 11. Reference numeral 30 in the drawing denotes a second inflow portion for raw material particles which is also provided integrally with the main body 22 by branching from the middle of the first inflow portion 29. This is the second inflow portion to which the connecting pipe 20 is attached at the open end. It is in communication with the inside of the hopper 12. And in the illustrated one, the first inflow part 29 and the second
The inflow portion 30 has an inner diameter ratio of approximately 4: 1.
In addition, an air flow path 32 is provided through a tubular partition wall 31 on the outer periphery of the internal space 23 that serves as the flow path 26 for the raw material particles except for the front end portion on the front end side where the first inflow portion 29 of the main body 22 is opened. A communication port 33 for communicating with the internal space 23 is formed on the tip side thereof at intervals on the same circumference, and an air inflow part 34 is formed on the base end side through the body 22. A compressed air supply means (not shown) is connected to the air inflow portion 34.

In order to mold a foamed synthetic resin molded article from two different kinds of raw material particles using such a foam molding machine, the following is carried out. First, for example, white expanded polystyrene beads are placed in the first hopper 11 as raw material particles, and colored expanded polystyrene beads are placed in the second hopper 12 as raw material particles. Then, the valves of the first hopper 11 and the second hopper 12 and the valve 21 provided in the middle of the connecting pipe 20 connecting the second hopper 12 and the raw material filling feeder 13 are opened. Then a pair of molds
Cylinder of raw material filling feeder 13 with molds 14 and 15 closed
25, the piston at the end of its piston rod 28
As shown in FIG. 2, 27 is retracted to the base end side of the internal space 23 of the main body 22.

In this state, when compressed air is supplied from the air inflow portion 34 of the raw material filling feeder 13, this compressed air is supplied to the main body.
22 of the inner space 23 from the air flow path 32 on the outer periphery of the communication port 33, further from the inner space 23 through the open end thereof into the molding space 16, facing the molding space 16 side of the pair of molds 14, 15. It flows out from the heating chambers 17 and 18 behind it through pores or slits (not shown) provided on the side. At this time, the main body
A negative pressure state is formed behind the communication port 33 of the internal space 23 of the 22, and the raw material particles put into the first hopper 11 from the first inflow portion 29 side and from the second inflow portion 30 side to the second hopper 12 side. The raw material particles put in the above are simultaneously supplied to the flow passage 26 inside the main body 22, and after passing the position of the communication port 33, the raw material particles ride on the flow of compressed air and are sequentially filled in the molding space 16. Then, in the vicinity of the branch portion of the first inflow portion 29 with the second inflow portion 30, since the inner diameter of the first inflow portion 29 is larger than the inner diameter of the second inflow portion 30, the raw material particles of the first inflow portion 29 are The flow is slow, and the flow of the raw material particles in the second inflow section 30 intersecting with this flow is faster than this
The raw material particles supplied from the inflow portion 30 are mixed so as to be sequentially introduced into the flow of the raw material particles supplied from the first inflow portion 29. Therefore, two kinds of different raw material particles are surely mixed uniformly in the required ratio in this portion,
It is possible to obtain a homogeneous molded product. Therefore, it can be said that the inner diameter of the first inflow portion 29 is preferably larger than the inner diameter of the second inflow portion 30. The inner diameter ratio of the first inflow part 29 and the second inflow part 30 is appropriately set according to the expansion ratio, particle size, and density of different types of raw material particles.

Immediately before the molding space 16 is completely filled with two kinds of different raw material particles, for example, 1 to 2 seconds before, the valve 21 is closed and the raw material from the second hopper 12 is closed. Stop the supply of particles. This is because when the molding space 16 is completely filled with the raw material particles, there is no escape path for the compressed air, and a blowback phenomenon occurs.
The compressed air flows backward to the 11 side and the second hopper 12 side, whereby the raw material particles in the second hopper 12 are transferred to the first hopper 11
This is to prevent people from entering inside. According to the results of the experiment, the raw material particles are completely filled in the molding space 16
If the valve 21 is closed 2 seconds before, the first hopper will be closed.
The raw material particles in the second hopper 12 did not flow back into the inside of 11.

Next, the cylinder 25 is actuated, and the piston 27 at the tip of the piston rod 28 is advanced as shown by the chain line in FIG. 2 to close the open end of the internal space 23 of the raw material filling feeder 13.

The heating chamber 1 behind the pair of molds 14 and 15
Steam is supplied to 7 and 18 from the steam pipe to cause heat welding between the raw material particles, and then water or air is supplied to the heating chambers 17 and 18 from the water pipe or the air pipe to cool the pair of molds 14 and 15. . next,
The mold 15 not provided with the raw material filling feeder 13 is moved laterally, and the molded product remaining in the other mold 14 is extruded by a release pin and taken out.

The foamed synthetic resin molded article molded in this manner has an appearance in which white raw material particles and colored raw material particles are arranged in a mosaic pattern, and is composed of only white raw material particles and colored raw material particles. Compared with the molded product, the appearance was colorful and the appearance was good. Further, it was possible to carry out molding at a low cost as compared with a molded product molded only with expensive colored raw material particles.

In such an expansion molding machine, expanded polystyrene beads, expanded polypropylene beads, expanded polyethylene beads, etc. can be used as the raw material particles. Then, it becomes possible to mold a molded article from any two kinds of different raw material particles such as raw material particles made of the same material but having different expansion ratios, raw material particles different in material, or raw material particles having different particle diameters.

When a foamed synthetic resin molded article is molded from three or more kinds of different raw material particles, the raw material filling feeder 13 is further provided with a third inflow portion apart from the first inflow portion 29 to the second inflow portion 30.
If a portion below the inflow portion is provided in a branched manner and these third and subsequent inlet portions are connected to the third hopper and below by a connecting pipe provided with a valve in the middle, a molded product can be easily molded.

Next, FIG. 3 shows a foam molding machine in which a valve 35 is provided in the middle of a connecting pipe 19 for connecting the first hopper 11 and the raw material filling feeder 13. In this foam molding machine, in addition to the above-described method of using the foam molding machine, the first hopper 11 or the second hopper 12 is initially filled in the molding space 16 with the raw material particles.
Only the valves 35 and 21 of the connecting pipes 19 and 20 are opened to supply only the raw material particles in the first hopper 11 or the second hopper 12. Then, the raw material particles are fed to the raw material filling feeder in the molding space 16.
Since it is filled from the part away from 13, it is filled as shown. Next, while closing the valves 35 and 21 on the one side and opening the valves 35 and 21 on the other side, this time, the raw material particles in the hoppers 11 and 12 on the other side are supplied and filled as shown by a chain line in the figure. . After this, again one hopper 1
The valves 35 and 21 of 1 and 12 are opened, the valves 35 and 21 of the other are closed, and the raw material particles in one of the hoppers 11 and 12 are filled into the molding space 16 again. According to this method, for example, by using raw material particles having the same material and different expansion ratios,
It is possible to make the inner side of the molded product highly foamed compared to the outer side to reduce the weight, or conversely to improve the cushioning performance.

In the foam molding machine shown in FIG. 1, the valve 21 is closed, and in the foam molding machine shown in FIG. 3, one of the valves 21 and 35 is opened and the other is closed. As in the conventional foam molding machine, it is possible to mold a molded product from a single type of raw material particles.

[0023]

EFFECTS OF THE INVENTION In the method for molding a foamed synthetic resin molded product according to the present invention, a molded product can be easily molded from two or more kinds of different raw material particles by simply putting the different kinds of raw material particles into the hopper. Further, the molded product thus obtained can solve or reduce the problems of the molded product molded from a single kind of raw material particles. Further, it becomes possible to uniformly mold a molded product composed of two or more kinds of different raw material particles.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an outline of a foam molding machine used in a molding method of a foam synthetic resin molded product according to the present invention.

FIG. 2 is a sectional view of a raw material filling feeder of this.

FIG. 3 is an explanatory view showing a part of the outline of another aspect of the foam molding machine.

FIG. 4 is an explanatory view showing an outline of a conventional foam molding machine.

[Explanation of symbols]

 11 First hopper 12 Second hopper 13 Raw material filling feeder 14 Mold for molding 15 Mold for molding 16 Molding space 17 Heating chamber 18 Heating chamber 19 Connecting pipe 20 Connecting pipe 21 Valve 22 Main body 23 Internal space 24 Mounting flange 25 Cylinder 26 Flow path 27 Piston 28 Piston rod 29 First inflow part 30 Second inflow part 31 Partition wall 32 Air flow path 33 Communication port 34 Air inflow part 35 Valve

Claims (5)

[Claims] 1. A molding space formed between two or more hoppers containing different kinds of raw material particles through a single raw material filling feeder and between a pair of molding dies of a foamed synthetic resin molded product whose molds are closed. A method for molding a foamed synthetic resin molded article, characterized by filling different types of raw material particles into a molded article. 2. A molding space formed between molding dies of a pair of foamed synthetic resin molded products which are closed through a single raw material filling feeder from two or more hoppers containing different kinds of raw material particles. 1. A method for molding a foamed synthetic resin molded article, characterized in that raw material particles of different types are mixed and evenly filled therein at the same time to form a molded article. 3. The method for molding a foamed synthetic resin molded article according to claim 1, wherein the different kinds of raw material particles are different in color. 4. The method for molding a foamed synthetic resin molded article according to claim 1, wherein the different types of raw material particles are raw material particles made of the same material but having different expansion ratios. 5. The method for molding a foamed synthetic resin molded article according to claim 1, wherein the different types of raw material particles are raw material particles having different materials.