JPH0592491A - Production of foamed plastic product and device therefor - Google Patents

Abstract

PURPOSE:To shorten a molding cycle by a method wherein a foamed plastic product is cooled by cooling molds from the top and rear surfaces thereof by using cooling fluid sprayed to the rear surfaces of the molds in mold chambers provided on the rear surfaces of the molds and cooling fluid supplied to a parting line chamber in the joint of both the molds. CONSTITUTION:Cooling lines 11, 12 are provided in mold chambers 8, 9 formed on the rear surfaces of molds 1, 2 in a pair of master frames 4, 5, which are separably provided opposed to each other. Furthermore, a cooling tube 13 for supplying cooling fluid into a parting line chamber 10 formed in the joint of the molds 1, 2 is connected to either the master frame 4 or 5. In this manner, a foamed plastic product thermally molded in the cavity formed between the pair molds 1 and 2 can be cooled uniformly in a short time without generating a temperature difference in both the molds 1, 2 as a whole, and a molding cycle can be reduced to a great extent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a foamed plastic product capable of shortening a molding cycle.

[0002]

2. Description of the Related Art As a method for producing a foamed plastic product, a method is generally used in which a cavity formed between a pair of molds is filled with foamable plastic beads for heating and foaming, followed by cooling and taking out from the cavity. ..

However, in the conventional method for producing a foamed plastic product of this kind, as shown in Japanese Patent Laid-Open No. 58-31722, the molded product is cooled in the mold backside in the mold chamber on the backside of each mold. Since it is only done with the cooling fluid sprayed towards,
There was a problem in that the cooling water was not sprayed to the seams of the mold and the like with a normal amount of cooling fluid and cooling was insufficient, so that the mold temperature could not be lowered uniformly.
Also, if a large amount of cooling water is sprayed to sufficiently cool the front side of the mold, the back side is excessively cooled and water adheres to the inside of the mold chamber to block the vent hole provided in the mold. In the vacuum vaporization process, the foamed plastic product cannot be sufficiently vaporized by suction, resulting in a product with a high water content, and there is a problem that the product must be taken out of the mold and then dried in another drying chamber. In addition, the adhered water flows into the cavity from the vent hole in reverse, which deteriorates the flow of the expandable plastic beads in the next cycle and causes the formation of dumpling-like adherents, which causes the end filling. There was a problem that it was hindered.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and cools the concave-convex mold uniformly and in a short time without causing a temperature difference, thereby greatly shortening the molding cycle. In addition, the amount of water used in the cooling spray is small, and the water content in the product can be reduced, and the subsequent drying process can be omitted, and moisture does not adhere to the cavity. The present invention has been completed for the purpose of providing a method and an apparatus for producing a foamed plastic product which can smoothly perform the filling of expandable plastic beads in the next cycle.

[0005]

SUMMARY OF THE INVENTION The present invention, which has been made to solve the above-mentioned problems, is to fill foamable plastic beads in a cavity formed between a pair of molds, heat-foam and then cool. In the method of manufacturing a foamed plastic product taken out from a cavity, cooling of the foamed plastic product is performed by cooling fluid sprayed toward the back surface of the mold in a mold chamber on the back surface side of each mold and a parting line formed at the joint of both molds. A method for producing a foamed plastic product, characterized by performing mold cooling from both front and back sides with a cooling fluid supplied to a chamber, and one master frame with a mold attached to the open end and the other with a mold attached to the open end Mold chamber formed on the back side of the mold in both master frames by facing the master frame of In a foamed plastic product manufacturing apparatus provided with a cooling pipe, both molds are mounted on both master frames so that a parting line chamber is formed between the mounting parts of both molds when the molds are matched, Furthermore, a cooling pipe for supplying a cooling fluid to the parting line chamber is connected to a position close to the opening end of the master frame, and the apparatus for producing a foamed plastic product is characterized in that.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the illustrated embodiments. The drawings show a molding machine for simultaneously producing four foamed plastic products, wherein 1 and 2 are a pair of molds, and in the embodiment, one is a fixed mold and the other is fitted in the concave mold. The cavity 3 is a movable mold that forms the cavity 3. 4 is a master frame for a concave mold that fixes the one mold 1 with an inside plate 6a,
Reference numeral 5 denotes a convex master frame for fixing the other mold 2 with an inside plate 6b. Both master frames 4 and 5 are attached to a mold clamping mechanism (not shown) and face each other so that they can come into contact with and separate from each other. Further, back plates 7a and 7b are attached to the master frames 4 and 5, respectively, and mold chambers 8 and 9 are formed on the back surfaces of the molds 1 and 2, respectively, and at the joints of the molds 1 and 2. A parting line chamber 10 is formed which is surrounded by the periphery of the mounting portion located and the portions near the open ends of the master frames 4 and 5. In the example, all the parting line chambers 10 of the four sets of molds for simultaneously producing four foamed plastic products are in a state of communicating with each other in a grid pattern, but it is designed arbitrarily according to the number of sets of molds. Of course, it can be changed.

Cooling pipes 11 and 12 with nozzles 11a and 12a for cooling the molds 1 and 2 from the back side are arranged in the mold chambers 8 and 9, respectively, and the cooling pipes 11 and 12 are external pipes.
On the other hand, a cooling pipe 13 for cooling the molds 1 and 2 from the surface side is connected to the parting line chamber 10 which is connected to the uppermost part 11b and 12b. Further, discharge pipes 14a and 14b for discharging the cooling fluid sprayed from the cooling pipes 11 and 12 toward the back surfaces of the molds 1 and 2 are connected to the lower ends of the mold chambers 8 and 9, respectively. Parting line chamber 1 located at the bottom
A discharge pipe 15 for discharging the cooling water supplied to each parting line chamber 10 through the cooling pipe 13 is also connected to 0.

In the structure thus constructed, the master frames 4 and 5 are brought close to each other by the operation of a mold clamping mechanism (not shown) to align the molds 1 and 2, and the inside of the cavity 3 formed by the molds 1 and 2 is formed. It is the same as the conventional method in that a foamed plastic product is manufactured by filling foamable plastic beads into a foamed plastic bead, heat-foaming the foamed product, and releasing the molded product from the cavity 3 after cooling. For cooling the product, the cooling fluid sprayed from the cooling pipes 11 and 12 arranged in the mold chambers 8 and 9 located on the back side of the molds 1 and 2 and the mounting portion front surface side of both molds 1 and 2 are cooled. The mold is cooled from both the front and back sides by the cooling fluid supplied through the cooling pipe 13 to the parting line chamber 10 formed at the located joint.

The cooling process will be described in more detail. As a first step, the external pipes 11b of the cooling pipes 11 and 12,
The water cooling valves 16 and 16 provided in the mold 12b are opened, and the nozzles 11a and 12a in the mold chambers 8 and 9 are used to mold 1,
2 is performed by spraying cooling water toward the back surface side, and at the same time, by opening the water cooling valve 17 provided in the cooling pipe 13, the cooling water is circulated in each parting line chamber 10 to form the concavo-convex mold 1. 2 is also performed from the front side. Next, the air valves 18 and 18 provided in the external pipes 11b and 12b of the cooling pipes 11 and 12 and the air valve 19 provided in the cooling pipe 13 are opened, and the back and front surfaces of the molds 1 and 2 are similarly set. Evaporative cooling is provided from both sides. In addition,
Drain valves 20 and 20 and vacuum valves 21 and 21 are provided in the discharge pipes 14a and 14b of the mold chambers 8 and 9, respectively.
In addition, the exhaust pipe 1 of the parting line chamber 10
5 is also provided with a drain valve 22 and a vacuum valve 23, and is operated so as to perform a discharge process in response to the supply of the cooling water or cooling air.

In this manner, the foamed plastic product in the cavity 3 is cooled uniformly from both front and back sides of the molds 1 and 2, so that a temperature difference is not generated on the entire surface of the molds and the molds are uniform and short in time. The cooling process is completed in about 30 minutes compared to the conventional method.
It was possible to shorten by%. Further, since the cooling water sprayed from the nozzles 11a and 12a was also small, the water content of the obtained products was all 5% or less, and it was not necessary to carry out the drying treatment in the subsequent step.

In the embodiment, the external pipes 11b and 12 of the cooling pipes 11 and 12 arranged in the mold chambers 8 and 9 are also used.
The steam valves 24, 24 for heat treatment are further provided in b, and the steam valve 25 for heat treatment is also provided for the cooling pipe 13 connected to the parting line chamber 10 to fill the cavity 3 with the expandable plastic beads. Similar to the above cooling treatment, the heating treatment of (2) is performed simultaneously from both the front and back sides of the concave and convex molds 1 and 2 so that the number of heating pipes can be reduced, and the heating cycle can be performed more uniformly and in a shorter time. I am trying. In this case, the discharge pipes 14a, 14b and the discharge pipe 15 are provided with steam discharge valves 26, 26 and a steam discharge valve 27, respectively, so that the discharge treatment is carried out corresponding to the supply of the heating steam.

[0012]

As is apparent from the above description, according to the present invention, the molding cycle can be significantly shortened by cooling the molds uniformly and in a short time without causing a temperature difference between them and the cooling. The amount of water used for spraying can be reduced,
Moreover, it is possible to reduce the water content in the product and to omit the subsequent drying treatment work, and to ensure that moisture does not adhere to the cavity and that the expandable plastic beads for the next cycle can be filled smoothly. There are many advantages such as being able to. Therefore, the present invention greatly contributes to the industrial development as a method and apparatus for producing a foamed plastic product that eliminates the conventional problems.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the device of the present invention.

[Explanation of symbols]

 1 One type 2 The other type 4 Master frame 5 Master frame 8 Type chamber 9 Type chamber 10 Parting line chamber 11 Cooling pipe 12 Cooling pipe 13 Cooling pipe

Claims (4)

[Claims] 1. A method for producing a foamed plastic product, wherein a foamable plastic bead is filled in a cavity formed between a pair of molds, heated and foamed, and then cooled and taken out from the cavity. , Performing mold cooling from both the front and back sides with the cooling fluid sprayed toward the mold back surface in the mold chamber on the back surface side of each mold and the cooling fluid supplied to the parting line chamber formed at the joint of both molds. And a method for producing a foamed plastic product. 2. The heating of the foamed plastic product is such that the heating fluid sprayed toward the back surface of the mold in the mold chamber on the back surface side of each mold and the heating fluid supplied to the parting line chamber formed at the joint of both molds. The method for producing a foamed plastic product according to claim 1, which is carried out by heating the mold from both the front and back sides with. 3. A master frame (4) having a mold (1) attached to the opening end and another master frame (5) having a mold (2) attached to the opening end are opposed to each other so that they can be separated from each other. Cooling pipes (11), (12) in the mold chambers (8), (9) formed on the back side of the molds (1), (2) in the master frame (4), (5)
In a foamed plastic product manufacturing device with
Both molds (1), (2) are both molds (1), (2) when matched
It is attached to both master frames (4) and (5) so that a parting line chamber (10) is formed between the attachment parts of the master frame (4) and (5). An apparatus for producing a foamed plastic product, characterized in that a cooling pipe (13) for supplying a cooling fluid to the parting line chamber (10) is connected at a close position. 4. A heating fluid source comprising cooling pipes (11), (12) arranged in mold chambers (8), (9) and a cooling pipe (13) for supplying cooling fluid to a parting line chamber (10). An apparatus for producing a foamed plastic product according to claim 3, wherein the apparatus can be switched and connected.