JPH05285928A - Production of hydraulic inorganic molded object - Google Patents

Abstract

PURPOSE:To shorten a dehydration time and to obtain a uniform molded object by holding filter cloth impregnated with an aqueous solution of polyacrylamide between two split molds to partition a cavity and injecting a hydraulic inorg. material into the space between one mold and the filter cloth to dehydrate the same from a large number of the small holes formed to the split molds under suction. CONSTITUTION:The concn. of an aqueous solution of polyacrylamide to be infiltrated in filter cloth is pref. 0.05wt.% or more. A hydraulic inorg. material contains cement and water and a water-soluble polymer, a reinforcing fiber, aggregate or the like can be added to the inorg. material. Upper and lower molds 2,3 have a large number of small holes 21, 31 made in the molding surfaces thereof and close the vacuum chambers 41, 51 connected to suction devices 4, 5. Filter cloth 7 is provided to the upper surface of the lower mold 3 under tension and sufficiently impregnated with the aqueous solution of polyacrylamide to be closed by the upper mold 2. A predetermined amount of a molding material is injected in the molds from the injection pipe 61 provided to the upper mold and sucked to remove excessive water from the small holes 21, 31. By this constitution, a dehydration time can be shortened and a molded object of high strength can be obtained.

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 slate roof tile.

[0002]

2. Description of the Related Art As a method for producing a hydraulic inorganic molded article such as slate roof tile, for example, Japanese Patent Publication No. 59-37202, Japanese Patent Publication No. 59-37203, and Japanese Patent Publication No. 61-51.
A method as described in Japanese Patent No. 521 has been proposed. That is, these methods are fluid hydraulics having fluidity obtained by kneading and mixing a predetermined amount of raw materials including cement, aggregate, reinforcing fiber and water in a mold cavity formed by closing two divided molds. After filling with an inorganic molding material (hereinafter referred to as "molding material" only), the excess water of the molding material is depressurized and dehydrated from the small holes provided on the mold surface by suction from the outside of the mold to form a shaped object of a desired shape. I'm trying to get it.

[0003]

However, according to these methods, since dehydration takes a long time, partial separation of cement and water occurs in the mold before shaping, and complete shaping cannot be performed. Or, the strength of the cured product may be uneven.
Therefore, there is also a method of using polyacrylamide in the molding material as a dehydration aid, but mixing the polyacrylamide in the molding material in advance, cement in the mold, aggregate,
Since the reinforcing fibers and the like are separated from each other, a uniform shaped article cannot be obtained.

In view of such circumstances, it is an object of the present invention to provide a method for producing a hydraulic inorganic molded article which can shorten the dehydration time and obtain a uniform shaped article.

[0005]

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

In the above structure, the concentration of the polyacrylamide aqueous solution with which the filter cloth is impregnated is not particularly limited,
It is preferably set to 0.05% by weight or more. The cement is not particularly limited, and examples thereof include Portland cement, Amilna cement, blast furnace cement and the like.
In addition, in the molding material, in addition to cement, water-soluble polymer,
Reinforcing fibers, aggregate (inorganic filler), etc. can be appropriately mixed.

Examples of the water-soluble polymer include methyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, hydroxyethyl cellulose, polyallyl acid and the like. As the reinforcing fibers, vinylon fibers, polyamide fibers, polyester fibers, synthetic fibers such as polypropylene fibers, inorganic mineral fibers such as wollastonite,
Alkali resistant glass fiber, carbon fiber and the like,
It is preferable that the thickness is 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 addition is 100 parts by weight of cement,
If it is 0.3 parts by weight or less, the desired strength of the molded article cannot be obtained, and if it exceeds 7 parts by weight, the dispersion of fibers tends to be poor and the fluidity at the time of shaping tends to be poor.

As the aggregate, blast furnace slag, silica sand, river sand,
Examples include fly ash, silica flower, bentonite, sepiolite, wollastonite, calcium carbonate, mica and the like. If the average particle size of the aggregate is 100 μm or more, it is difficult for the particles of the aggregate to enter between the fibers of the reinforcing fiber and the fibers tend to aggregate without being dispersed. Therefore, the average particle size is 100 μm or less. Preferably.

The filter cloth is not particularly limited as long as it is a material whose dimension expands and expands when an external force is applied and has corrosion resistance to the molding material. For example, cloth using crimped yarn or Examples thereof include porous rubber.

[0010]

According to the above construction, first, the filter cloth is soaked with a polyacrylamide aqueous solution having a predetermined concentration as a dehydrating aid. Then, after closing both split molds, a molding material is injected between the filter cloth and one split mold. By this injection, the filter cloth stretches and comes into close contact with the mold surface of one of the split molds.
Therefore, the molding material fills the mold cavity formed by the two split molds.

Next, suction is performed through at least the small hole of the other split mold, and excess water of the molding material in the mold cavity is dehydrated through the filter cloth to obtain a shaped article. Since polyacrylamide has been impregnated in advance, this polyacrylamide acts as a dehydration aid and can shorten the dehydration time. Moreover, since polyacrylamide is not mixed in the molding material, there is no concern that each component in the molding material is affected by polyacrylamide and separated.

[0012]

EXAMPLES Examples of the present invention will be described in detail below.
FIG. 1 shows an example of a molding apparatus used for carrying out the manufacturing method of the present invention. As shown in the figure, 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 each have a large number of small holes 21 and 31 formed on the mold surfaces thereof, and block the decompression chambers 41 and 51 connected to the suction machines 4 and 5, respectively. There is. Further, 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 open, the filter cloth 7 was sufficiently impregnated with a 0.05 wt% polyacrylamide aqueous solution. Next, after closing the upper mold 2 and the lower mold 3, the molding material in the molding material tank 6 is injected from the molding material supply pipe 61 between the upper mold 2 and the filter cloth 7, and a predetermined amount of molding material is injected. When possible, the valve 62 was closed and the suction devices 4 and 5 were operated to depressurize the inside of the decompression chambers 41 and 51 to dehydrate and remove excess water in the molding material through the small holes 21 and 31. 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 object could be taken out from the lower mold 3 while being stuck to the upper mold 2 by the suction of the suction device 4. Then, the upper mold 2 was moved to a cradle (not shown), suction was stopped, the shaped object was placed on the cradle, and cured in the curing step to obtain a predetermined molded product. The molding materials used in this example had the following blending ratios.

Ordinary Portland cement (manufactured by Ube Industries, Ltd.) 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 that used in Example 1 was previously mixed in the 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 the above-mentioned Example 1 and Comparative Examples 1 and 2 and the measurement result 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 from place to place.

As shown in Table 1, according to the method of the present invention, the dehydration time can be shortened and a high-strength molded product can be obtained. The method for producing a hydraulic inorganic molded article according to the present invention is not limited to the above-mentioned examples. For example, in the above-described embodiment, the upper mold 2 and the lower mold 3 are simultaneously sucked and dehydrated, but the lower mold 3 may be suctioned for dehydration. Also,
In the above-described embodiment, the shaped object is moved to the upper mold 2 by suction of the upper mold 2.
I tried to open the mold by sucking it on, but suction is not always necessary.

[0021]

EFFECTS OF THE INVENTION Since the method for producing a hydraulic inorganic molded product according to the present invention is constituted as described above, the time for dehydrating excess water in the molding material during shaping can be greatly shortened, and the productivity can be improved. Is improved. Moreover, a high-strength molded product can be stably supplied.

[Brief description of drawings]

FIG. 1 is a cross-sectional 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.

[Explanation of symbols]

 2 Upper mold (divided type) 3 Lower mold (divided type) 7 Filter cloth 21 Small hole 31 Small hole

Claims (1)

[Claims] 1. A filter cloth made of an extensible material is disposed in a mold cavity, which is formed by closing two divided molds having a large number of small holes formed in the mold surface, and divides one of the divided molds. Between the mold and the filter cloth, a step of injecting a hydraulic inorganic molding material containing a predetermined amount of cement and water, and excess water in the hydraulic inorganic molding material by suction from the small holes of at least the other split mold. A method for manufacturing a hydraulic line inorganic molded article comprising a step of dehydrating and shaping, characterized in that a filter cloth is impregnated with an aqueous solution of polyacrylamide of a predetermined concentration before injecting the hydraulic inorganic molding material. And a method for producing a hydraulic inorganic molded article.