JP3090805B2 - Method for producing hydraulic inorganic molded article - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a hydraulic inorganic molded article.

[0002]

2. Description of the Related Art Conventionally, in order to form a molded article having a complicated shape using a molding material mainly composed of a hydraulic inorganic substance such as cement, gypsum, and calcium silicate forming material, for example, Japanese Patent Publication No. 59-37202 No., JP-B-59-37203
As disclosed in Japanese Patent Application Publication No. 61-51521 and Japanese Patent Publication No. Sho 61-51521, a molding material is formed from a material injection port provided in a second split mold in a mold cavity formed by closing a first split mold and a second split mold. Is injected and filled at a predetermined injection pressure, and then excess water is dehydrated under reduced pressure through a drainage hole formed in the wall surface of the first split mold through a filtering material to form.

[0003]

However, the above method has the following problems. In other words, there is a time lag before the molding material is injected between the vicinity of the injection port of the material and the part distant from the injection port, and excess moisture of the molding material is preferentially discharged from the part injected through the drain hole. Since the water is dehydrated outside, there is a difference in the dehydration time between the vicinity of the injection part and the part far from the injection part.

[0004] Accordingly, even in the same shaped product, the moisture content differs between a portion corresponding to the vicinity of the injection portion and a portion corresponding to the portion far from the injection portion even in the same shaped product. The molded product obtained by curing and curing has strength,
There is a possibility that physical properties such as density may vary. This is because, as is well known, the strength of cement decreases as the ratio (W / C ratio) of the water to be kneaded to the cement (W / C ratio) increases, and the other quality performance (frost resistance, etc.) also decreases. is there.

The present invention has been made in view of the above circumstances, and provides a method for producing a hydraulic inorganic molded article capable of performing uniform dehydration as a whole and obtaining a molded article having uniform physical properties. It is intended to be.

[0006]

In order to achieve such an object, a method for producing a fiber-reinforced hydraulic inorganic molded article according to the present invention is characterized in that a first split mold having a large number of drain holes formed in a wall surface. A hydraulic inorganic molding material is injected and filled into a mold cavity formed by closing the second split mold, and the hydraulic inorganic molding material filled from the drain hole by suction from outside the first split mold. Is a method for producing a hydraulic inorganic molded product in which excess water is dewatered outside the mold and shaped into a desired shape, and the injection pressure of the hydraulic inorganic molding material is completed until the injection of the hydraulic inorganic molding material is completed. A pressure was applied from the outside of the mold through the drain hole with an air pressure so as to prevent the excess water from flowing out of the mold, and after the injection was completed, the water was sucked from the outside of the first split mold.

In the above structure, the injection pressure of the hydraulic inorganic molding material is not particularly limited, but is preferably about 3 to 6 kg / cm ² . The air pressure applied from outside the mold is not particularly limited, but the pressure difference from the injection pressure is preferably 1 kg / cm ² or more. The suction pressure during dehydration is not particularly limited,
About 650 mmHg is preferable.

[0008] It is preferable to provide an extensible filtering material along the inner wall of the first split mold. The material of the filtering material is a material whose dimensions expand and its area expands when an external force is applied, and examples thereof include a cloth using a crimped yarn and a porous rubber. Examples of the hydraulic inorganic substance include those which are hardened by a hydration reaction of cement, gypsum, calcium silicate forming material and the like.

In addition to hydraulic minerals, molding materials include reinforcing fibers such as mineral fibers, glass fibers, plant and animal fibers, synthetic fibers, semi-synthetic fibers, sand, gravel, rapid hardened materials, pigments and the like as aggregates. Materials that can be used for the production of general inorganic molded products can also be appropriately mixed as needed.

[0010]

According to the above construction, almost no dehydration is performed until the injection is completed, and the entire molding material injected into the mold cavity can be dehydrated simultaneously and within the same time. Therefore, the obtained shaped product has a uniform moisture content throughout the shaped product.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments. Example 1 As shown in FIG. 1, an upper mold 1 as a second split mold and a lower mold 2 as a first split mold were closed. In the figure, 3 is a mold cavity, and 4 is a filtering material made of a stretching material.

A compressor (not shown) is operated to send compressed air from the exhaust pipe 21 provided in the lower mold 2 to the lower mold 2, and the mold cavity 3 is maintained while maintaining the air pressure in the air chamber 23 at 5 kg / cm ^2. A molding material having the following composition was injected from the injection pipe 11 at an injection pressure of 6 kg / cm ² . During this injection, the excess moisture of the molding material did not escape from the drain hole 22 to the outside of the mold cavity 3. When the injection was completed, the filter medium 4 was in close contact with the inner wall surface of the lower mold 2.

Mixing of molding material Ordinary Portland cement (manufactured by Ube Industries) 100 parts by weight Vinylon fiber (RM182 × 3 mm manufactured by Kuraray) 2 parts by weight Water 500 parts by weight After the compressor is stopped, a vacuum pump (not shown) is turned on. The air is exhausted from the exhaust pipe 21 to reduce the air pressure in the air chamber 23 to −650 mmHg, and the excess moisture of the molding material injected into the mold cavity 3 through the drain hole 22 and the filter material 4 is removed. Dehydrated.

After sufficient dehydration, the vacuum pump is stopped, the upper mold 1 and the lower mold 2 are opened, and the shaped material in the mold is taken out, and the shaped material is cured and cured by a known method. A molded product was obtained.

(Comparative Example 1) A molded product was obtained in the same manner as in Example 1 except that the inside of the air chamber 23 was not pressurized when the molding material was injected into the mold cavity 3.

The porosity, bending strength, and variation in bending strength of the part corresponding to the molding material injection port and the part furthest from the injection port of the molded articles obtained in Example 1 and Comparative Example 1 were measured. The results are shown in Table 1. In Table 1, part A represents a part corresponding to the injection port, and part B represents a part farthest from the injection port.

[0017]

[Table 1] From the above Table 1, the molded product obtained in Example 1 is the same as Comparative Example 1
It can be seen that the porosity and the bending strength are stable in all the parts in comparison with the molded product obtained in the above.

[0018]

The method for producing a hydraulic inorganic molded article according to the present invention is configured as described above, so that almost no dehydration is performed until the injection is completed, and the entire molding material injected into the mold cavity is formed. At the same time and within the same time, and the resulting shaped article has a uniform moisture content throughout the shaped article.

Therefore, a molded product obtained by curing and curing this shaped product is free from variations in physical properties such as bending strength in the same molded product, and is a product having uniform quality and high commercial value.

[Brief description of the drawings]

FIG. 1 is a view showing an example of a molding apparatus used for carrying out a method for producing a hydraulic inorganic molded article according to the present invention, and shows a state before a hydraulic inorganic material is injected into a mold cavity. It is a sectional view showing.

[Explanation of symbols]

 Reference Signs List 1 upper mold (second split mold) 2 lower mold (first split mold) 3 mold cavity 4 hydraulic inorganic molding material 22 drain hole

Claims (1)

(57) [Claims] 1. A hydraulic inorganic molding material is injected and filled into a mold cavity formed by closing a first split mold having a large number of drainage holes formed in a wall surface and a second split mold. A method for producing a hydraulic inorganic molded product in which excess moisture of a hydraulic inorganic molding material filled from the drain hole by suctioning from the outside of a split mold is dehydrated and shaped into a desired shape, comprising: Until the injection of the inorganic molding material is completed, pressurize from outside the mold through the drain hole with air pressure slightly smaller than the injection pressure of the hydraulic inorganic molding material so that excess moisture does not escape outside the mold, and the injection is completed. And then suctioning from the outside of the first split mold.