JPH05237952A - Metal die for plastic foaming and foaming method - Google Patents

Abstract

PURPOSE:To provide a molding metal die for foam polystyrene product wherein retaining quantity of water at rear faces of metal dies after completion of cooling process is unified and next pressure reducing cooling process can be performed efficiently. CONSTITUTION:In a metal die device of plastic foaming, rear sides of a pair of metal die bodies 1 facing each other detachably are formed in a heating and cooling chamber section 4. The device comprises, at predetermined parts on the rear faces of the metal die bodies 1, water retaining sections 5 for retaining cooling water to be supplied to the chamber section 4 so as to nearly unify the retaining quantity of water on the whole face of the metal die bodies 1. In a forming method, a part of the cooling fluid is left nearly uniformly on the rear faces of the metal die bodies by using the above device so as to cool the whole of the metal die bodies nearly uniformly by latent heat of vaporization of the residual cooling fluid in the water retaining sections.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin in which raw material beads supplied to a cavity formed between a pair of mold bodies are heated and foamed by a heating fluid supplied to a chamber and then cooled by a cooling fluid. The present invention relates to a mold device for foam molding of a synthetic resin used in foam molding and a foam molding method.

[0002]

2. Description of the Related Art For example, in the molding of expanded polystyrene products, a mold molding apparatus for foam molding of synthetic resin is used, in which the back sides of a pair of mold bodies that are opposed to each other so as to be freely separated from each other are formed in a chamber for heating and cooling. , The pre-foamed raw material beads are filled in the cavity formed between both mold bodies, heated and foamed by the pressurized steam supplied to the chamber, and the cooling water is sprayed to the chamber and residual cooling is performed. It is common to perform cooling by the latent heat of vaporization of water, etc., and then take out the expanded polystyrene product from the cavity, but in the conventional molding method of this kind, the water retention amount on the back side of the mold after the cooling process with cooling water is completed. However, there is a problem in that the subsequent reduced pressure cooling step cannot be performed efficiently because of the variation in temperature.

That is, there is a large amount of residual water in the near-horizontal portion of the back surface of the mold, whereas in the vertical portion and the reverse taper portion, the residual water drops due to its own weight and almost disappears. When the amount of retained water becomes non-uniform and cooling under reduced pressure is performed in this state, the cooling effect of the latent heat of vaporization is large at the places with a lot of residual water, and the cooling effect due to the latent heat of vaporization becomes small at the places with a small amount of residual water, and It was not possible to perform uniform cooling. As a result, there is a problem that the molding cycle has to be unnecessarily lengthened by the time required for cooling the part with a small cooling effect, and the temperature will be reduced when the mold is heated again for the next molding cycle. There is a problem that unevenness occurs and uniform heating and foaming cannot be performed, which causes a defective product to be produced.Moreover, it takes a long time to raise the temperature of the supercooled part to a predetermined temperature, and the molding cycle becomes long, resulting in molding efficiency. There is also a problem in that the energy becomes worse and a large amount of energy is required for heating.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and equalizes the amount of water retained on the back surface of the mold body after the water cooling step, so that the next reduced pressure cooling step can also be performed. It can be performed uniformly and efficiently, and the entire mold body can be uniformly heated to a predetermined temperature for a next molding cycle in a short time to mold high-quality products, and the molding cycle can be significantly shortened. And a highly efficient and economically efficient production by promoting energy saving and energy saving, and since there is no excessive cooling, there is no cooling water that could not be evaporated and a dry molded product can be obtained. The present invention has been completed for the purpose of providing a foam molding die device and a foam molding method.

[0005]

SUMMARY OF THE INVENTION The present invention, which has been made to solve the above-mentioned problems, is a synthetic resin in which the back sides of a pair of mold bodies which are opposed to each other so as to be freely separated from each other are formed in a chamber for heating and cooling. In the foam molding die device, a water retaining portion for retaining the cooling water supplied to the chamber portion and substantially equalizing the water retaining amount on the entire surface of the die body is provided at a required portion of the back surface of the die body. A mold device for foam molding of a characteristic synthetic resin, and a heating device for supplying pre-foamed raw material beads to a cavity formed between a pair of mold bodies and supplying them to a chamber portion on the back side of the mold bodies. In a foam molding method of a synthetic resin, which is heated and foamed by a fluid and then cooled by a cooling fluid supplied to the chamber portion, one of the cooling fluid supplied to the chamber portion is provided on a required rear surface of the mold body. Water retention holding part Is provided so that a part of the cooling fluid remains substantially uniformly on the back surface of the mold body, and the entire mold body is cooled substantially uniformly by the latent heat of vaporization of the residual cooling fluid in the water retaining portion. This is a resin foam molding method.

[0006]

The present invention will now be described in detail with reference to the illustrated embodiments. The drawing shows an example of a mold apparatus for molding a polystyrene foam product, in which the back sides of a pair of mold bodies facing each other so as to be freely separated from each other are formed in a chamber for heating and cooling. The mold body, 2 is a master frame, 3 is an aluminum plate that covers the back side of the master frame 2,
Reference numeral 4 denotes a heating / cooling chamber portion formed on the back surface side of the mold body 1.

In the present invention, a water retaining portion 5 for retaining a part of the cooling fluid supplied to the chamber portion 4 is provided in a required portion of the back surface of the mold body 1 having poor water retaining ability after the cooling step. Has been. The poor water retention portion is a portion where the cooling water drops by its own weight after the water cooling process is completed and almost no residual water is left, for example, a vertical portion or a downward surface portion. The water retaining portion 5 is formed as a plurality of recessed grooves 6 extending in the horizontal direction so as to prevent the water from falling after the water cooling process and sufficiently retain the water. Mold body 1
The water retention amount on the entire back surface is substantially uniform.

The shape and the number of the recessed grooves 6 are arbitrarily designed according to the mold to be used. In addition, the water retaining portion 5 is formed by the disappearance model casting method as shown in FIG. It is also possible to form the formed concavities and convexities 7 or a water-absorbing substance 8 such as a polyester non-woven fabric attached to the back side of the mold body 1 as shown in FIG.

[0009]

With this structure, the pre-foamed raw material beads are filled in the cavity formed between the pair of mold bodies 1 and 1 and heat-foamed by a conventional method, and then the back surface of the mold is Cooling is performed by spraying water into the chamber 4 with a spray nozzle (not shown), and further vacuum suction is performed inside the chamber 4 to perform depressurized cooling, thereby making the entire die body substantially uniform by latent heat of vaporization of residual cooling water. It is similar to the conventional one in that it is cooled to mold an expanded polystyrene product, but a water retaining portion 5 is provided in a portion of the back surface of the mold body 1 where water retention is poor, and the water cooling step is performed. After the end, sufficient residual water will be stored in the water retention part 5 even in the part where the water retention was conventionally poor, and the amount of water retention on the entire back surface side will be substantially uniform. To mold body Substantially becomes possible cooling by uniform vaporization latent heat is performed across the back surface side, with the mold body 1 becomes to be cooled to a predetermined temperature uniformly in a short time,
Reheating for the next molding cycle can be performed uniformly and in a short time. Further, as shown in FIG. 1, a part of the residual water may be blown off by an air jet nozzle 9 directed to a portion where the residual water is large, prior to the reduced pressure cooling step. Therefore, uniform cooling can be performed.

When the water retaining portion 5 is provided on the back surface side of the mold body 1 as described above, the horizontal portion and the vertical portion at the upper portion after the depressurization cooling step (pressure reduction degree minus 0.8 kg) are completed. It was confirmed that the temperature difference was 1 ° C. or less and the sample was cooled sufficiently uniformly, and that it was confirmed to have a remarkable effect as compared with the conventional temperature difference of about 20 ° C.

[0011]

As is apparent from the above description, according to the present invention, the subsequent reduced pressure cooling step can be performed uniformly and efficiently by making the water retention amount on the back side of the mold uniform after the water cooling step. It is possible to heat the entire mold uniformly to a predetermined temperature for the next molding cycle in a short time to mold high-quality products, and to greatly shorten the molding cycle and save energy. Therefore, it is possible to realize extremely efficient and economical production, and there is also an advantage that it can be applied to a conventional die by only making a simple improvement. Therefore, the present invention, as a mold device and a foam molding method for foam molding of a synthetic resin that have eliminated the conventional problems, has a great contribution to the development of the industry.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the device of the present invention.

FIG. 2 is a cross-sectional view showing another embodiment.

FIG. 3 is a cross-sectional view showing another embodiment.

[Explanation of symbols]

 1 Mold Main Body 2 Master Frame 4 Chamber Section 5 Water Retaining Section 6 Recessed Groove 7 Unevenness 8 Water Absorbing Substance

Claims (6)

[Claims] 1. A pair of mold bodies facing each other so as to be able to come into contact with and separate from each other.
In the mold device for foam molding of synthetic resin in which the back side of (1) is formed in the chamber part (4) for heating and cooling, the chamber part (4) is supplied to the required part of the back surface of the mold body (1). A mold apparatus for foam molding of synthetic resin, which is provided with a water retaining section (5) for holding cooling water to be retained and for making the water retaining amount of the entire surface of the mold body (1) substantially uniform. 2. The mold apparatus for foam molding of synthetic resin according to claim 1, wherein the water retaining portion (5) is a groove (6) formed on the back surface of the mold body (1). 3. The mold apparatus for foam molding of synthetic resin according to claim 1, wherein the water retaining portion (5) is an unevenness (7) formed on the back surface of the mold body (1) by the disappearance model casting method. 4. The mold apparatus for foam molding of synthetic resin according to claim 1, wherein the water retaining portion (5) is a water absorbing substance (8) attached to the back side of the mold body (1). 5. The pre-expanded raw material beads are supplied to a cavity portion formed between a pair of mold bodies, and are heated and foamed by a heating fluid supplied to a chamber portion on the back side of the mold bodies. In the foam molding method of a synthetic resin designed to be cooled by a cooling fluid supplied to a chamber, a water retention part for holding a part of the cooling fluid supplied to the chamber part is provided in a required part of the back surface of the mold body. Part of the cooling fluid remains substantially uniformly on the back surface of the mold body, and the entire mold body is cooled substantially uniformly by the latent heat of vaporization of the residual cooling fluid in the water retaining section Molding method. 6. The method according to claim 5, wherein after the cooling fluid is supplied to the chamber portion, air blowing is performed to adjust the removal of the residual residual cooling water so that the amount of the cooling fluid left on each part of the back surface of the mold body is substantially equalized. A foam molding method of the synthetic resin described.