JPS581657B2 - Kanetsuhouhou - Google Patents

Description

[Detailed description of the invention] The present invention relates to a heating method in foam molding.

Conventionally, in order to shorten the molding cycle time in foam molding, a large diameter drain pipe was connected to the steam chamber of the mold to quickly drain the cooling water that filled the air chamber during the cooling process. ing.

However, in the mold heating process, the mold is heated and the condensed water is discharged from the drain pipe, so the discharge capacity is inappropriately large and the steam injected into the steam chamber is effective in heating the mold. There is a tendency for the steam to pass through and be discharged without any effect, and therefore, it has been necessary to inject excessive steam to compensate for the amount of steam that is ineffective for heating the mold.

The present invention is a foam molding method that improves the heating efficiency of steam to the mold and significantly reduces the amount of steam used by setting the opening area of the steam chamber of the mold to be large or small depending on the cooling process and heating process. The present invention provides a heating method for heating.

The present invention will be specifically explained below based on the drawings.

The drawing shows a mold apparatus for foam molding used for carrying out the method of the invention, in which a fixed frame 1a and a movable frame 1b include:
A fixed mold 2 and a movable mold 3 each made of a material with excellent thermal conductivity such as aluminum are attached.

Each of the molds 2 and 3 has a hollow steam chamber 21 and 31 inside, and on opposing surfaces there is a convex part 32 on one side and a concave part on the other side to form a cavity 4 when both molds are closed. 22, and steam holes 23, 33 such as core vents are provided in each mold part 32, 22 at appropriate intervals.

The upper walls of both molds 2 and 3 are provided with steam pipes 24 and 34, respectively, which communicate with the steam chamber. In addition to connecting the cold water discharge pipes 25 and 35, there are large-diameter drain pipes 26 and 36 on the lower wall, and a small-area drain discharge pipe 27 that prevents steam from passing through but allows a moderate amount of steam and condensate to be released. 37 are connected and communicated.

Each drain discharge pipe 27, 37 has an on-off valve 28, respectively.
, 38 and control valves 29, 39 for adjusting the discharge amount.

Then, the reciprocating device 5 connected to the moving frame 1b is operated to close both the molds 2 and 3 to form the cavity 4,
After completing the process of filling the cavity 4 with foamable synthetic resin particles using the filling device 6, the steam pipes 24.3 of each mold 2, 3
4 and drain discharge pipes 27, 37, when opening the on-off valves 28, 38 of the steam chambers 21, 31 of both types.
, 34 are injected.

Since the drain discharge pipes 27 and 37 have a small area, the steam hardly passes through the steam chamber, and the steam fills the steam chambers 21 and 31 and effectively heats the mold.

Condensate and low-temperature steam condensed due to heating of the mold gather at the bottoms of the steam chambers 21 and 31 and are discharged from small-area discharge pipes 27 and 3.
It is gradually released from 7 onwards.

Next, one mold 3 opens only the steam pipe 34 and closes the drain discharge pipe 37 and the drain pipe 36, and the other mold 2 closes the steam pipe 24, opens the drain discharge pipe 27, and closes the steam pipe 34.
By injecting steam from the steam chamber 31 of one mold to the cavity 4 and the steam chamber 21 of the other mold.
The vapor is then discharged to the outside, allowing the vapor to uniformly permeate between the expandable resin particles filled in the cavity 4, resulting in homogeneous foam molding.

After performing the mold heating process and, if necessary, the above-mentioned steam passage process, the drain discharge pipes 27 and 37 of each mold 2 and 3 are closed, and only the steam pipes 24 and 34 are opened to fill the steam chamber with steam. .

The steam in both steam chambers enters the cavity 4 from each steam hole in the mold section and heats and foams the synthetic resin raw particles.

After the foaming process, the steam pipes 24, 34 of each mold 2, 3 are closed, the cold water discharge pipes 25, 35 are opened to inject cooling water, and the large-area drainage pipes 26, 36 are opened. The water cools the back of the mold and immediately
Water runs from.

Incidentally, if the drain discharge pipes 27 and 37 are also opened at this time, the cooling water can be discharged even more efficiently.

After the molds have cooled, both molds 2 and 3 are opened and the molded product is taken out from the cavity 4, completing one molding cycle.

The above steps are continuously repeated to automatically form a large number of foam molded products.

In addition, when implementing the present invention, the above-mentioned drain discharge pipe 2
7 and 37 are molds 2 and 3 corresponding to the size of cavity 4.
A plurality of each may be provided.

As described above, in the present invention, since the drain discharge pipes 27 and 37 having an appropriate discharge capacity are opened separately and independently from the drain pipe, steam fills the steam chambers 21 and 31 and molds the mold. It acts effectively on heating, and the same molding as conventional methods can be performed with the minimum amount of steam. The amount of steam used varies depending on the shape of the molded product, but savings of 10 to 50% can be achieved.

For example, when 1 kg of expanded polystyrene is expanded 45 times using a mold equipped with a drain pipe with an inner diameter of 80 mm and a cavity size of 700 x 900 m, the condensation and low temperature generated in the mold heating process and steam passing process are If the steam is released by opening the above drain pipe as in the past, it will be 25-30%.
kg of steam was required, but when the above process was carried out with a 3/4 inch drain discharge pipe installed in the steam chamber, the amount of steam used was significantly reduced to 15 to 22 kg. We have confirmed that this is particularly effective in saving money.

Furthermore, since the drain pipes 26 and 36 are closed during mold heating and are not involved in the release of steam, they can be made sufficiently large in diameter, and the drain speed can therefore be kept within or increased from the conventional one.

In addition, since condensate or low-temperature steam flows out from the drain discharge pipes 27 and 37, and hot water flows out from the drain pipes 26 and 36, they are separated and discharged. It has many excellent effects, such as the ability to reuse cooling water and released steam.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional view of a mold apparatus for foam molding used to carry out the method of the present invention. 2...Fixed mold, 3...Moveable mold, 2
1, 31... Steam room, 24, 34...
...Steam pipe, 25, 35...Cold water discharge pipe,
26, 36... Drain pipe, 27, 37...
...Drain discharge pipe, 4...Cavity.

Claims (1)

[Claims] 1 The process of closing a pair of foam molds and filling the cavities with foamable synthetic resin particles, and opening the steam pipes and small-area drain discharge pipes communicating with the steam chamber of each mold to heat the molds and release condensate. The mold heating process involves opening only the steam pipe in the steam chamber of each mold, filling it with steam, and foaming the resin particles. In the steam chamber of each mold, a large-area drainage pipe is opened and the mold is heated. A heating method for foam molding, characterized by carrying out a series of a cooling step in which water is sprayed onto the mold to cool the mold and drain water, and a mold opening step in which the mold is opened and a molded product is taken out.