JP3002346B2 - Manufacturing method of hardened cement - 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 hardened cement used as a building material.

[0002]

2. Description of the Related Art Hardened cement bodies are used in various fields, but the demand is remarkably large especially for building materials. Therefore, in manufacturing a cement cement, it is very important to improve productivity while maintaining strength, and in particular, the extrusion molding method has been attracting attention because it can efficiently produce a molded article having an irregular cross section. I have.

When a cement composition is molded by an extrusion method to produce a hardened cement, it is necessary to be able to mold at a low extrusion pressure in order to increase productivity. When asbestos is blended, molding can be performed with a low extrusion pressure by the action of a forming aid by asbestos, and asbestos plays an important role in strength. Recently, however, the amount of asbestos has been reduced in consideration of the effect on the human body, and with the reduction of asbestos, a large amount of methylcellulose (MC) such as hydroxypropylmethylcellulose has been added as a molding aid. ing.

[0004]

But MC The present invention is to provide a high material unit price, that a large amount of MC'm me so may cause the cost up. MC also improves moldability and improves strength.
Therefore, alternatives need to be considered. The present invention has been made in view of the above points, and it is an object of the present invention to provide a method for producing a hardened cement body that can enhance moldability without having to mix a large amount of MC and can maintain strength. It is the purpose.

[0005]

Means for Solving the Problems A method of manufacturing a hardened cement body according to the present invention, e with including modified polycarboxylic acid
The present invention is characterized in that a cement composition to which a nonionic surfactant is added is extruded, and this molded product is cured and hardened.

Hereinafter, the present invention will be described in detail. The cement composition contains aggregates, asbestos, fibers,
It is prepared by mixing a colorant and the like and kneading it with water, and any cement such as ordinary Portland cement, slag cement, alumina cement, or early-strength cement can be used. As the aggregate, silica, silica powder, silica sand, fly ash, slag, crushed stone and the like can be used. Fibers include polypropylene fiber, vinylon fiber, acrylic fiber, pulp,
Carbon fibers, cotton, hemp, metal fibers and the like can be used. Further, as a coloring agent, iron black, carbon black, chromium oxide, or the like can be used.

In the present invention, the modified polycarboxylic acid is blended with the cement composition to stably disperse cement and aggregate to reduce secondary agglomeration and reduce the pressure required during extrusion molding. The extrusion pressure can be reduced, and even if the amount of asbestos is reduced, the moldability of the cement composition can be kept high and the strength of the hardened cement can be maintained. By adding the modified polycarboxylic acid in this manner, the amount of MC added can be reduced. The amount of MC added is preferably 1% by weight or less based on the solid matter of the cement composition.

As the modified polycarboxylic acid, an ether-modified or ester-modified polymethacrylic acid can be used. For example, as a commercial product, “SF230G” manufactured by Sanyo Chemical Industries, Ltd. can be used.
Here, the unmodified polycarboxylic acid has poor stability even when the cement or the aggregate is dispersed, and may be re-agglomerated. Therefore, the modified polycarboxylic acid is used in the present invention. The amount of the modified polycarboxylic acid is 0.05 to 0.5 with respect to the solid of the cement composition.
% By weight is preferred. If the addition amount is less than 0.05% by weight, the effect of improving the moldability and strength by blending the modified polycarboxylic acid cannot be sufficiently obtained. Conversely, if the addition amount exceeds 0.5% by weight, the setting delay of cement becomes large due to the modified polycarboxylic acid, and it becomes difficult to use it practically. A styrene-maleic acid copolymer polyethylene oxide adduct can be used as a material capable of obtaining the same effect as the modified carboxylic acid. Further, a salt of a modified polycarboxylic acid can also be used.

When the modified polycarbonate is added to the cement composition as described above, air tends to be entrained in the system and the specific gravity of the cured cement body tends to decrease. So , strange
The above-mentioned reduction of extrusion pressure and maintenance of moldability by adding an ether-based nonionic surfactant (ether-based nonionic surfactant) together with a water- soluble polycarboxylic acid
And while achieving retention of strength of the cured cement, such as crushing the air bubbles while preventing the entrainment of air, der which can be made to maintain a high specific gravity
You . Polyoxyalkyl ethers and the like can be used as the ether-based nonionic activator, and commercially available products such as “Cedran FF1” manufactured by Sanyo Chemical Industries, Ltd.
80 "can be used. Even when the ether-based nonionic surfactant is added in excess of 0.1% by weight based on the solid content of the cement composition, the effect of increasing the specific gravity is not increased, so the amount of the ether-based nonionic surfactant added is It is preferably set to 0.1% by weight or less based on the solid matter of the cement composition. "Fomaster PC" manufactured by San Nopco Co., Ltd. can be used as a material capable of obtaining the same effect as this ether-based nonionic surfactant.

[0010] First, solids such as cement and other aggregates, asbestos, fibers, coloring agents, etc. are mixed, and further, a modified polycarboxylic acid and an ether-based nonionic activator and, if necessary, MC are further mixed and mixed. Then, a cement composition for extrusion molding is prepared by adding a liquid such as water and kneading with a kneading machine, and after extruding the cement composition with an extrusion molding machine, steam curing, autoclave By curing and curing, a cured cement body can be produced. When extruding the cement composition in this way, since the modified polycarboxylic acid is blended in the cement composition, the extrusion pressure is reduced, the moldability is increased, and the productivity can be improved. is there. In addition, since the amount of asbestos can be reduced with the compounding of the modified polycarboxylic acid, the wear of screws, barrels, dies, etc. of extruders and kneaders can be reduced, and in this regard, cost reduction is also attempted. Is what you can do.

[0011]

The present invention will now be illustrated by examples. (Examples 1 to 4 and Comparative Examples 1 to 4 ) The components were mixed and kneaded with the components shown in Tables 1 and 2 to prepare a cement composition, which was extruded, steam-cured, and autoclaved. A hardened cement body was manufactured. still,
"SF230G" manufactured by Sanyo Chemical Industries, Ltd. was used as the modified polycarboxylic acid, and "Cedran FF180" manufactured by Sanyo Chemical Industries, Ltd. was used as the ether non-ionic activator.

In the extrusion molding, the pressure required for the molding was measured to evaluate the moldability. Further, the bending strength and the absolute specific gravity of the obtained hardened cement were measured. The results are shown in Tables 1 and 2.

[0013]

[Table 1]

[0014]

[Table 2]

As can be seen from Tables 1 and 2, it is confirmed that the compounding of the modified polycarboxylic acid can lower the extrusion pressure, improve the moldability, and increase the bending strength. . It is also confirmed that the addition of an ether-based nonionic activator can keep the absolute specific gravity high.

[0016]

As described above, according to the present invention, a cement composition containing a modified polycarboxylic acid and containing an ether-based nonionic activator is extruded. It can stably disperse cement and the like to reduce secondary agglomeration, reduce the pressure required during extrusion molding and lower the extrusion pressure, and even if the amount of asbestos is reduced, the cement composition are those of the strength of the cured cement can be held it is possible to maintain a high moldability of the object state, and are not may be further reduced the amount of MC, yet anti-entrained air into the system
To stop the air bubbles and crush the air bubbles.
It can keep the weight high.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yasuhiro Sakamoto 1048 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) References JP-A-3-215335 (JP, A) JP-A-63-246414 ( JP, A) JP-A-6-127992 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B28B 21/54 B28B 3/20

Claims (1)

(57) [Claims] 1. An ether containing a modified polycarboxylic acid.
A method for producing a hardened cement body, comprising extruding a cement composition to which a non-ionic surfactant is added , and curing and hardening the formed body.