JPS5856511B2 - Molding method for thermosetting materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for molding thermosetting materials such as glass fiber reinforced cement materials and resin concrete materials.

Conventionally, this type of thermosetting material has been molded by a method in which the material is injected into a mold, the mold is heated, and the molded product is released after thermosetting, or a mold heated above the curing temperature. This is done by injecting a material into the mold and releasing the molded product after heat curing.

However, in the case of the former method, it takes time to heat the mold, and when molding is repeatedly performed, the mold must be cooled down to a certain extent before injecting the next material, so the molding cycle is delayed. It was long and extremely inefficient.

On the other hand, when using the latter method, the molding cycle is shortened to some extent, but even when trying to obtain a molded product such as a thin-walled box-shaped container, the injected material does not fully reach every corner of the mold. Since the resin is thermally hardened, there are problems in that defective products occur one after another and it is impossible to obtain satisfactory thin-walled molded products.

The present invention has been made to solve the above-mentioned problems at once, and after storing an inner mold for molding in an outer mold heated to a temperature higher than the curing temperature of a thermosetting material, the inner mold is A thermosetting material is injected into the inner mold, and the entire inside of the middle mold is filled with the material before it is thermoset as the temperature of the middle mold rises.After the material is almost hardened, the middle mold is replaced with an outer mold. This relates to a method for molding a thermosetting material, the gist of which is to take the material out of the mold and immediately introduce it into a heat insulating device to completely harden the material.

Hereinafter, the molding method of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic explanatory diagram sequentially showing each step of the molding method of the present invention, in which 1 is a supply device for thermosetting material a;
2 is an outer mold that is divided into upper and lower parts and has a built-in heater 21, 3 is an inner mold that is divided into upper and lower parts and has a fine air vent hole (not shown) and an injection port 31, and 4 is a heat retention device. be.

That is, in the molding method of the present invention, the heater 21 as shown in FIG.
The process starts by housing the inner mold 3 as shown in Figure 1 in the upper and lower two-part type outer mold 2 which is constantly heated above the curing temperature of the thermosetting material a.

This middle mold 3 is a thin-walled mold with a wall thickness of about 5 to 20 fi and a small heat capacity, and is either not preheated or is preheated to a temperature far lower than the curing temperature, and is inserted into the outer mold 2 in this way. Because of the thin wall, the temperature quickly rises above the curing temperature.

Therefore, in the molding method of the present invention, immediately after the inner mold 3 is installed, that is, at a stage where the temperature of the inner mold 3 is insufficiently raised and the thermosetting material a is not thermoset even if it is injected, as shown in FIG. As shown in FIG.
is injected into the middle mold 3 to ensure that every corner is filled, and maintained as it is for a predetermined period of time.

During this time, the temperature of the middle mold 3 rises above the curing temperature, whereby the thermosetting material a inside is thermosetted.

After curing in this manner, the outer mold 2 is opened as shown in FIG. 1d, and the middle mold 3 is taken out, and then the heat insulating device 4 is passed through as shown in FIG. 1e, and the middle mold 3 is opened as shown in FIG. 1f. to release the molded product A.

The heat retention step shown in Fig. 1e is incorporated to completely cure the thermosetting material a, and the middle mold 3 is removed before the material a is completely cured in the heat curing process shown in Fig. 1c. Even if the product is taken out, the curing reaction can be completed in this heat retention process, thereby making it possible to shorten the time required for the heat curing process.

The molding method of the present invention uses a large number of medium molds to repeatedly perform molding one after another in the manner described above, and after releasing the molded product A, the medium mold is repeatedly used for the next molding. used.

In addition, in order to easily release the molded product A and to obtain a molded product with a smooth and glossy surface, the inner mold 3 is replaced with the outer mold 2.
It is desirable to coat the inner surface of the middle mold 3 with a suitable mold release agent in advance before filling it in the mold.

According to the molding method of the present invention as described above, the inner mold 3 housed in the outer mold 2 which is constantly heated above the curing temperature is heated before the temperature rise is insufficient and the thermosetting material a does not harden. Curing material a
is injected into the middle mold 3, so that the thermosetting material a is reliably filled into every corner of the middle mold 3 without curing midway.
After that, the thermosetting material a hardens as the temperature rises above the hardening temperature of the middle mold 3, so even when obtaining a thin-walled molded product with a wall thickness of several millimeters, it is possible to use the same method as in the conventional second method. The occurrence of such defective molded products becomes almost non-existent.

Moreover, the wall thickness of the middle mold 3 is 5 to 5, as mentioned above.
201a, and when it is stored in the outer mold 2, the temperature quickly rises above the curing temperature. Compared to the case of heating, it is possible to significantly shorten the time required to raise the temperature, and in addition, as mentioned above, the inner mold 3 is replaced with the outer mold 2 before the thermosetting material a is completely cured. Even if the molded product A is removed from the mold, it is completely cured by the heat insulating device 4, so the time required for the heat curing process is further shortened. Since there is no need to cool the mold as in the first conventional method, it is possible to significantly shorten the molding cycle and improve productivity.

In addition, such a thin-walled medium mold 3 can be obtained relatively inexpensively and is lightweight, making it easy to handle. For example, even when coating with a mold release agent, it can be fixed in conventional equipment. Compared to coating a mold that has been previously coated, the coating workability is much better and is advantageous.

As described above, the molding method of the present invention is extremely useful because it makes it possible to obtain thin-walled molded products with high productivity by using a medium mold.

Next, examples of the molding method of the present invention will be described.

EXAMPLE A glass fiber reinforced cement material having the following composition was prepared and stored in the supply device 1.

(Ingredients) (Parts by weight) Thermosetting cement 100 Cal.
50 silica sand
50 pigment 10 alkali-resistant glass fiber chop 8 water
60 Next, the inner mold 3 whose inner surface was coated with a mold release agent was heated to about 100°C.
Immediately after storing the inner mold 3, the above-mentioned material was injected into the inner mold 3 from the supply device 1 and maintained as it was for 5 minutes.

Thereafter, the middle mold 3 is taken out from the outer mold 2 and supplied to a heat insulating device 4 at 80°C, while the next middle mold 3 is stored in the outer mold 2, and the above materials are similarly injected and thermally cured. , the operation of feeding the removed inner mold 3 to the heat insulating device was repeated.

In this way, molded products with a wall thickness of 6 m (300x300
x701igil box-shaped container) was released from the mold, and the cooled inner mold 3 was repeatedly used for molding.

In this way, molded products were obtained one after another, but although the obtained molded products were all thin-walled products with a wall thickness of 671 gl1, they were molded according to the shape of the middle mold 3 and had no missing parts. Moreover, they were all excellent products with smooth, metallic-like glossy surfaces and no air bubbles, and the molded products could be easily released from the middle mold 3.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic illustration of an embodiment of the molding method of the present invention. Brief explanation of the drawings, 1... Supply device, 2...
...Outer mold, 3...Middle mold, 4...
Heat retention device, a...Thermosetting material, A...
・Molded products.

Claims (1)

[Claims] 1. After storing the inner mold for molding in the outer mold heated to a temperature higher than the curing temperature of the thermosetting material, the thermosetting material is injected into the middle mold, and as the temperature of the middle mold increases, it is thermoset. Before this, fill the entire inside of the inner mold with the material, and after the material has almost hardened, take out the inner mold from the outer mold and immediately introduce it into a heat insulating device to completely harden the material. Characteristic molding method for thermosetting materials.