JP3009538B2 - Method for producing hydraulic inorganic molded article - Google Patents

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 a hydraulic inorganic molded article such as a slate roof tile.

[0002]

2. Description of the Related Art As a method for producing a hydraulic inorganic molded article such as a slate roof tile, for example, JP-B-59-37202, JP-B-59-37203, and JP-B-61-51
No. 521 proposes a method as described. That is, in these methods, a hydraulic fluid having fluidity obtained by kneading and mixing raw materials including a predetermined amount of cement, aggregate, reinforcing fibers and water in a mold cavity formed by closing two split molds. After filling with an inorganic molding material (hereinafter, simply referred to as “molding material”), the excess moisture of the molding material is depressurized and dewatered from small holes provided on the mold surface by suction from outside the mold to form a shaped article having a desired shape. I'm trying to get.

[0003]

However, according to these methods, since dewatering takes time, partial separation of cement and moisture occurs in the mold before shaping, and complete shaping is not performed. Or uneven strength of the cured product.
Therefore, there is a method of adding polyacrylamide in the molding material as a dehydration aid, but beforehand mixing polyacrylamide in the molding material, cement, aggregate,
Reinforcing fibers and the like are separated from each other, and a uniform shaped article cannot be obtained.

[0004] In view of such circumstances, an object of the present invention is to provide a method for producing a hydraulic inorganic molded article capable of shortening the dewatering time and obtaining a uniform shaped article.

[0005]

In order to achieve such an object, a method for producing a hydraulic inorganic molded article according to the present invention comprises the steps of forming two divided molds each having a large number of small holes formed in a mold surface. A filter cloth made of an extensible material is arranged in the closed mold cavity to partition both split molds, and between one split mold and the filter cloth,
A step of injecting a molding material containing a predetermined amount of cement and water, and a step of dehydrating and shaping excess water in the molding material by suction from at least the other divided small hole to form the hydraulic fluid mineral. A method for producing a molded article, wherein a filter cloth is impregnated with a predetermined concentration of a polyacrylamide aqueous solution before a molding material is injected.

In the above structure, the concentration of the aqueous solution of polyacrylamide impregnated in the filter cloth is not particularly limited,
It is preferable that the content be 0.05% by weight or more. Examples of the cement include, but are not particularly limited to, Portland cement, amylna cement, blast furnace cement, and the like.
Also, in the molding material, in addition to cement, water-soluble polymer,
Reinforcing fibers, aggregates (inorganic fillers) and the like can be appropriately mixed.

[0007] Examples of the water-soluble polymer include methylcellulose, carboxymethylcellulose, polyvinyl alcohol, hydroxyethylcellulose, and polyallylic acid. As the reinforcing fibers, synthetic fibers such as vinylon fiber, polyamide fiber, polyester fiber, and polypropylene fiber; inorganic mineral fibers such as wollastonite;
Alkali-resistant glass fiber, carbon fiber and the like,
It is preferable that the thickness is about 2 to 40 denier and the length is about 3 to 15 mm. When synthetic fibers are used as the reinforcing fibers, the amount of the added fibers is based on 100 parts by weight of the cement.
If the amount is less than 0.3 parts by weight, the desired strength of the molded article cannot be obtained, while if it exceeds 7 parts by weight, the dispersion of the fibers tends to be poor and the fluidity during shaping tends to be poor.

As aggregates, blast furnace slag, quartz sand, river sand,
Fly ash, silica flour, bentonite, sepiolite, wollastonite, calcium carbonate, mica, and the like. If the average particle size of the aggregate is 100 μm or more, the particles of the aggregate are difficult to enter between the fibers of the reinforcing fibers, and the fibers tend to aggregate without being dispersed. Therefore, the average particle size is set to 100 μm or less. Is preferred.

[0009] The filter cloth is not particularly limited as long as it is a material whose dimensions expand and its area expands when an external force is applied, and is not particularly limited as long as it has corrosion resistance to the molding material. Examples include porous rubber.

[0010]

According to the above construction, first, an aqueous solution of polyacrylamide having a predetermined concentration as a dehydration aid is impregnated into a filter cloth. Then, after the two split dies are closed, a molding material is injected between the filter cloth and one of the split dies. This injection causes the filter cloth to expand and come into close contact with the mold surface of one of the split molds.
Thus, the molding material fills the mold cavity formed by both split dies.

Next, suction is performed through at least the other divided mold small hole, and the excess moisture of the molding material in the mold cavity is dehydrated through a filter cloth to obtain a shaped product. Since the polyacrylamide has been impregnated in advance, the polyacrylamide acts as a dehydration aid and can shorten the dehydration time. In addition, since polyacrylamide is not mixed in the molding material, there is no fear that each component in the molding material is separated by the influence of polyacrylamide.

[0012]

Embodiments of the present invention will be described below in detail.
FIG. 1 shows an example of a molding apparatus used to carry out the manufacturing method of the present invention. As shown in the drawing, the molding apparatus 1 includes an upper mold 2 and a lower mold 3 as split molds.

The upper mold 2 and the lower mold 3 are each provided with a large number of small holes 21 and 31 in the mold surface and respectively close the decompression chambers 41 and 51 connected to the suction machines 4 and 5, respectively. I have. The tip of the molding material supply pipe 61 from the molding material tank 6 faces the center of the upper mold 2.

A filter cloth 7 is stretched on the upper surface of the lower mold 3. (Example 1) First, with the upper mold 2 and the lower mold 3 opened, a 0.05% by weight aqueous solution of polyacrylamide was sufficiently impregnated into the filter cloth 7. Next, after the upper mold 2 and the lower mold 3 are closed, the molding material in the molding material tank 6 is injected between the upper mold 2 and the filter cloth 7 from the molding material supply pipe 61, and a predetermined amount of the molding material is injected. When it was completed, the valves 62 were closed and the suction machines 4 and 5 were operated to reduce the pressure in the decompression chambers 41 and 51 to remove the excess moisture in the molding material through the small holes 21 and 31 by dehydration. Then, when the dehydration was sufficiently completed, the suction device 5 was stopped, and the upper mold 2 and the lower mold 3 were separated.

By this separation, the shaped product could be taken out of the lower mold 3 while being sucked to the upper mold 2 by the suction of the suction device 4. Then, the upper die 2 was moved to a pedestal (not shown) to stop suction, the shaped object was placed on the pedestal, and cured and cured in a curing and curing step to obtain a predetermined molded product. The molding materials used in the examples had the following compounding ratios.

Normal Portland cement (manufactured by Ube Industries) 100 parts by weight Vinylon (manufactured by Kuraray Co., Ltd. RM182 × 3 mm) 2 parts by weight Water 500 parts by weight (Comparative Example 1) A molded product was obtained in the same manner as in Example 1. Comparative Example 2 The same amount of polyacrylamide as used in Example 1 was previously mixed in a molding material, and a molded product was obtained in the same manner as in Comparative Example 1.

Table 1 shows the time required for dehydration in Example 1 and Comparative Examples 1 and 2, and the measurement results of the bending strength of the obtained molded product.

[0018]

[Table 1]

The bending strength of Comparative Example 2 was not constant because it varied depending on the location.

As shown in Table 1, according to the method of the present invention, the dewatering time can be shortened and a molded product having high strength can be obtained. The method for producing a hydraulic inorganic molded article according to the present invention is not limited to the above-described examples. For example, in the above-described embodiment, dehydration is performed by simultaneously sucking the upper mold 2 and the lower mold 3, but dehydration may be performed by suction only from the lower mold 3. Also,
In the above embodiment, the shaped object is sucked into the upper die 2
The mold was opened by sucking it on, but suction was not always necessary.

[0021]

The method for producing a hydraulic inorganic molded article according to the present invention is configured as described above, so that the time for dehydrating excess moisture in the molding material at the time of shaping can be greatly reduced, and the productivity is improved. Is improved. In addition, a high-strength molded product can be supplied stably.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a molding apparatus used to carry out a method for producing a hydraulic inorganic molded article according to the present invention.

[Explanation of symbols]

 2 Upper die (split type) 3 Lower die (split type) 7 Filter cloth 21 Small hole 31 Small hole

Claims (1)

(57) [Claims] 1. A filter cloth made of an extensible material is disposed in a mold cavity in which a plurality of small holes are formed in a mold surface so as to partition the two molds into one another. A step of injecting a hydraulic inorganic molding material containing a predetermined amount of cement and water between the mold and the filter cloth, and removing excess water in the hydraulic inorganic molding material by suction from at least the other small hole of the split mold. Dehydrating and shaping the molded article comprising a step of dehydrating and shaping, wherein the filter cloth is impregnated with a predetermined concentration of an aqueous solution of polyacrylamide before injecting the hydraulic inorganic molding material. A method for producing a hydraulic inorganic molded article.