JPH0890546A - Manufacture of inorganic cement plate - Google Patents

Abstract

PURPOSE: To eliminate the adherence of inorganic material for forming a green sheet to an upper press mold by pressing the sheet, and simultaneously sucking the air between the mold and an elastic sheet from vent holes. CONSTITUTION: When an upper press mold 1 is brought into contact with a green sheet 3, the air is reduced under pressure and evacuated from the vent holes 5 of the mold 1. On the other hand, the side end of the sheet 3 is so covered as to enclose the sheet 3 by an elastic sheet 2, and the air is reduced under pressure and exhausted from the vent holes 6 of a lower press mold 4. The sheet 3 is pressed, and held for five sec. The pressing is released, the mold 1 is raised, the pressurized air is supplied from the holes 5, and the sheet 3 is released from the mold 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an inorganic cement board in which a green sheet made of an inorganic material is press-molded and patterned, and is useful for, for example, ceramic-based exterior materials, roof tile materials, exterior members, etc. The present invention relates to a method for manufacturing an inorganic cement board.

[0002]

2. Description of the Related Art Conventionally, a green sheet made of an inorganic material containing cement as a main component and an aggregate or a fiber component is pressed between an upper press die having an uneven pattern and a flat lower press die. After that, it is cured and cured to produce an inorganic cement board. In such a method for producing an inorganic cement plate, when pressing the green sheet, there is a problem that the inorganic material constituting the green sheet is likely to adhere to the upper press die, conventionally, this problem has been solved. In order to do so, a method of applying a release agent to the upper press die to make it difficult for the inorganic material forming the green sheet to adhere thereto is generally performed. In addition, it is said that the upper press die is further provided with a vent hole, and after the press is completed, the pressure is released and the air is sent out from the vent hole to push out the green sheet with the uneven pattern to improve the mold release property from the upper press die. The method is being done at the same time.

[0003]

However, in the above-mentioned method, when the green sheet has a high water content or the adhesiveness becomes strong due to the material composition, the adhesion of the inorganic material to the upper press die is prevented. However, there is a problem that the mold release property from the upper press die is deteriorated. Furthermore, the method of extruding a green sheet having an uneven pattern with air has a problem in that it leaves traces of ventilation holes on the surface of the green sheet, which is not preferable in appearance.

The present invention has been made in order to solve the above problems, and an object thereof is to provide an upper press metal having an uneven pattern of an inorganic material forming a green sheet when the pressure is released after the press is completed. It is an object of the present invention to provide a method for producing an inorganic cement plate which does not adhere to a mold and has good demoldability from an upper press mold of a green sheet having an uneven pattern.

[0005]

According to the method for producing an inorganic cement board of the present invention, a green sheet is pressed between an upper press die having a concavo-convex pattern and a flat lower press die, and then cured by curing. In the method for producing an inorganic cement plate, the upper press die is provided with a vent hole, and an elastic sheet is interposed between the upper press die and the green sheet to press the upper press die and the upper press die and the elastic sheet at the same time. It is characterized in that the air interposed therebetween is sucked from the vent hole, and after the pressing is finished, the upper press die is opened and at the same time air is injected from the vent hole between the upper press die and the elastic sheet.

In the method for producing an inorganic cement board of the present invention, it is preferable that the elastic sheet is a rubber sheet having a thickness of 5 mm or less and an elongation rate of 50% or more.

It is also preferable to press the green sheet in a reduced pressure atmosphere. At this time, it is preferable that the lower press die is provided with a vent hole and air is sucked from the vent hole at the same time when the green sheet is pressed.

The green sheet used in the method for producing an inorganic cement board of the present invention will be described below.
The green sheet contains cement as a main component, and the aggregate and fiber components are selected from the inorganic aggregate and the organic aggregate, which are generally used according to the purpose, in the kind and amount thereof. is there. For example, as the cement, ordinary Portland cement, blast furnace cement, etc. can be used,
As the aggregate, silica stone powder, silica sand, silica, gravel, glass balloons, shirasu balloon, fly ash, perlite and the like can be used, and as the fiber component, cellulose-based pulp, mineral fibers such as asbestos, polypropylene, Resin fibers such as vinylon (trademark) can be used. The method for forming the green sheet is not particularly limited, and may be a papermaking method such as a Fourdrinier papermaking method or a Hatschek papermaking method, or may be extrusion molding or cast molding. .

The method of curing and curing the green sheet is not particularly limited, and a method of curing in a moist heat state, a method of curing in an autoclave, a method of using these in combination, and the like can be performed.

[0010]

According to the method for producing an inorganic cement board of the present invention, the green sheet is pressed, and at the same time, the air existing between the upper press die and the elastic sheet is sucked from the ventilation hole. The uneven pattern of the upper press die is applied to the upper surface of the green sheet through the elastic sheet so as to be in close contact with the surface of the mold having the uneven pattern. Therefore, the inorganic material forming the green sheet does not adhere to the upper press die. Further, after the pressing is completed, the upper press die is opened and at the same time air is injected from the ventilation hole between the upper press die and the elastic sheet, so that the green sheet provided with the uneven pattern from the upper press die together with the elastic sheet. Pushed out. Therefore, the releasability of the green sheet from the upper press die is improved, and no trace of vent holes is left on the surface of the green sheet.

Here, in the method for producing an inorganic cement board of the present invention, it is practically preferable that the elastic sheet is a rubber sheet having a thickness of 5 mm or less and an elongation of 50% or more. That is, the concavo-convex pattern of the upper press die actually has a different shape corresponding to the thickness of the elastic sheet and is provided on the upper surface of the green sheet.
In addition, since the thickness of the inorganic cement board produced from the green sheet obtained by papermaking is generally around 20 mm, when the thickness of the elastic sheet increases, the influence on the uneven pattern imparted to the green sheet also increases, which is preferable. Absent. By setting the thickness of the elastic sheet to 5 mm or less, the effect on the uneven pattern of the green sheet can be made practically problem-free. Further, when the elastic sheet has a low elongation, when the uneven pattern of the upper press die has deep undulations with large undulations, the elastic sheet is deformed and adheres along the uneven pattern of the upper press die. Can't do it. Elastic sheet elongation of 50%
With the above, there is no practical problem. Further, the rubber sheet is an elastic sheet that is excellent in elongation, has good airtightness, and can be obtained at a low cost, and is therefore preferable in practice.

In the method for producing an inorganic cement board of the present invention, when the green sheet is pressed in a depressurized atmosphere, the air between the green sheet and the elastic sheet is discharged during the pressing, and voids or the like are generated in the green sheet. It is possible to prevent it.

As an example of this method, when a lower press die is provided with a vent hole and air is sucked from the vent hole at the same time when the green sheet is pressed, an elastic sheet is adhered to the upper surface of the green sheet to become airtight. Therefore, the green sheet can be depressurized.

[0014]

EXAMPLES The present invention will be described below with reference to examples.

Preparation of Green Sheets Normal Portland cement 50%, silica sand (No. 6) 30
%, Silica stone powder 15%, and pulp (NUKP) 5% are added to prepare an inorganic solid content, and water is added to obtain a 5% aqueous slurry. This aqueous slurry is poured from the bottom onto a laminated body in which punching metal, felt, and filter paper are stacked in this order, and dehydrated under reduced pressure from the lower surface of the punching metal to obtain a green sheet having a water content of 45 to 65% and a thickness of 27 to 36 mm. obtain.

Example 1 First, as shown in FIG. 1 (a), a flat plate-shaped lower press die 4 provided with a vent hole 6 penetrating vertically and a concave and convex pattern on the lower surface, The above-mentioned green sheet 3 is placed on the lower press die 4 between the upper press die 1 and the upper press die 1 having the vent holes 5 penetrating up and down of the upper press die 1. , Set the elastic sheet 2 and set it. Here, the elastic sheet 2 is a sheet made of soft neoprene rubber having a thickness of 0.7 mm and an elongation of 70 to 80%. Further, the vent holes 5 and 6 of the upper press die 1 and the lower press die 4 are holes each having an inner diameter of 0.5 mm.
It is arranged so that the pressure can be reduced to 0 mmHg or less and the pressure can be increased to 3 atm.

Next, the upper press die 1 is lowered at a speed of 2 mm / sec. When the upper press die 1 comes into contact with the green sheet 3, the reduced pressure exhaust is started from the ventilation hole 5 of the upper press die 1. On the other hand, the elastic sheet 2 covers the side edge of the green sheet 3 so as to wrap the green sheet 3, and depressurizes and exhausts from the vent hole 6 of the lower press die 4 (however, depressurizing exhaust from the vent hole 6 is not essential). Then, the green sheet 3 is pressed at a pressure of 30 kg / cm ² and held for 5 seconds.

Then, the press is decompressed, and the upper press die 1
Is raised and pressurized air is supplied from the ventilation hole 5 to release the green sheet 3 from the upper press die 1. further,
Air is supplied to the atmospheric pressure from the ventilation holes 6, and the elastic sheet 2 is removed to obtain a green sheet 3 having an uneven pattern.

In the embodiment, as the upper press die 1, as shown in FIG. 2, an upper press die (A) having an uneven pattern in which the width of the concave and convex portions is 10 mm and the height of the unevenness is 3 mm is used. Pressing was performed using two types of upper press molds (B) having a concave and convex pattern having a concave and convex width of 10 mm and a concave and convex height of 7 mm.

With respect to the green sheet 3 after pressing, the adhesiveness of the inorganic material to the upper press die 1 and the release property of the green sheet 3 from the upper press die 1 were evaluated. Regarding the evaluation of the adhesiveness to the upper press mold 1, the presence or absence of the adhesion of the inorganic material to the upper press mold 1 was visually judged, and the mold release property from the upper press mold 1 was evaluated.
The ease with which the green sheet 3 was removed from the upper press die 1 was visually determined. The results are shown in (Table 1).

COMPARATIVE EXAMPLE 1 In Example 1, the elastic sheet 2 was not used, and neither the vacuum exhaust nor the pressurized air supply from the vent holes 5 and 6 was performed, and the other operations were performed in the same manner. It was

Comparative Example 2 In Comparative Example 1, release oil was applied to the concave and convex pattern of the upper press die 1 and pressing was performed in the same manner as other operations.

Comparative Example 3 In Example 1, instead of using the elastic sheet 2, neither reducing pressure exhaustion nor pressurized air supply from the vent hole 6,
Release oil was applied to the concave-convex pattern of the upper press die 1, and pressing was performed in the same manner as other operations.

For Comparative Examples 1 to 3, the adhesion of the inorganic material to the upper press die 1 and the demoldability of the green sheet 3 from the upper press die 1 were evaluated in the same manner as in Example 1. The results are shown in (Table 1).

[0025]

[Table 1]

From Table 1, in Example 1, there is no adhesion of the inorganic material to the upper press die 1, and the demoldability of the green sheet 3 from the upper press die 1 is also Comparative Examples 1 to 3. It turns out that it is better than On the other hand, even in Comparative Example 3 in which release oil is applied to the upper press die 1 to prevent the adhesion of the inorganic material, and air release from the upper press die 1 is also used, It can be seen that it is not possible to cope with the case where the upper press mold (B) having large unevenness of the uneven pattern is used as the mold 1. Further, in Comparative Example 3, the traces of the vent holes 5 were left on the upper surface of the obtained green sheet 3, whereas in Example 1, the traces of the vent holes 5 were not left.

Incidentally, it goes without saying that an inorganic cement board can be obtained by curing and curing the green sheet 1 obtained in Example 1 and provided with an uneven pattern under desired conditions.

[0028]

According to the method for producing an inorganic cement board of the present invention, since the air existing between the upper press die and the elastic sheet is sucked from the ventilation hole at the same time as pressing the green sheet, the elastic sheet can be moved upward. The uneven pattern of the upper press die is applied to the upper surface of the green sheet through the elastic sheet while being in close contact with the surface of the press die having the uneven pattern. Therefore, the inorganic material forming the green sheet does not adhere to the upper press die. Further, after the pressing is completed, the upper press die is opened and at the same time air is injected from the ventilation hole between the upper press die and the elastic sheet, so that the green sheet provided with the uneven pattern from the upper press die together with the elastic sheet. Pushed out. Therefore, the releasability of the green sheet from the upper press die is improved, and no trace of vent holes is left on the surface of the green sheet.

In the method for producing an inorganic cement board of the present invention, when the green sheet is pressed in a depressurized atmosphere, the air between the green sheet and the elastic sheet is exhausted during the pressing, resulting in voids and the like in the green sheet. It is possible to prevent it.

As an example of this technique, when a lower press die is provided with a vent and air is sucked from the vent at the same time as pressing the green sheet, an elastic sheet is adhered to the upper surface of the green sheet to make it airtight. Therefore, the green sheet can be put into a reduced pressure state during pressing.

[Brief description of drawings]

1A and 1B are cross-sectional views showing a pressing method according to an embodiment of the method for producing an inorganic cement board of the present invention.

2 (a) and 2 (b) are cross-sectional views of an upper press die used in Examples and Comparative Examples of the method for producing an inorganic cement plate of the present invention.

[Explanation of symbols]

 1 Upper press die 2 Elastic sheet 3 Green sheet 4 Lower press die 5 Vent hole

Claims (4)

[Claims] 1. A method for producing an inorganic cement board in which a green sheet is pressed and cured between an upper press die having a concavo-convex pattern and a flat lower press die, and a ventilation hole is provided in the upper press die. An elastic sheet is interposed between the upper press die and the green sheet for pressing, and at the same time, air present between the upper press die and the elastic sheet is sucked from the ventilation hole, and after the press is completed, A method for producing an inorganic cement board, which comprises injecting air between the upper press die and the elastic sheet from a ventilation hole while opening the upper press die. 2. The method for producing an inorganic cement board according to claim 1, wherein the elastic sheet is a rubber sheet having a thickness of 5 mm or less and an elongation of 50% or more. 3. The method for producing an inorganic cement board according to claim 1, wherein the green sheet is pressed in a reduced pressure atmosphere. 4. The method for producing an inorganic cement board according to claim 1, wherein the lower press die is provided with a vent, and the green sheet is pressed and air is sucked from the vent at the same time. .