JPH0442847A - Molding of inorganic building material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for molding inorganic building materials, and more particularly to an improvement in an extrusion molding method for inorganic building materials.

[Conventional technology]

Extrusion molding is well known as a means for forming inorganic building materials using cement as the main raw material, and is widely used as a means for producing long building materials with a single cross-sectional shape.

In this extrusion molding method, a cement mixture is generally extruded from a molding rod into a predetermined shape, placed on a pallet, and then cured to a degree that can be handled.
Then, it is removed from the pallet and subjected to a second curing process in an autoclave until it reaches its final strength.

[Problems with conventional technology]

By the way, in the above manufacturing method, it takes at least several hours for the primary curing to reach a handleable strength after the compacts are placed on the pallets, and during this period, the same number of pallets as the compacts are processed.
), so in the case of mass production, the number of pallets mentioned above becomes very large, and since the pallets are made of expensive material such as stainless steel, there is a problem that the equipment cost becomes very high.

To solve this problem, it is effective to shorten the primary curing time, and to add NaCl+C to the cement mixture.
It is conceivable to add a compound having early strength and quick hardening properties such as aC1□ and perform extrusion molding.

However, in extrusion molding, defective products are usually returned to the material supply port for reuse, so the returned material begins to harden inside the extruder, causing material to stagnate and causing material to become clogged. There was a problem that the molding itself became impossible.

In addition, a method has been proposed in which an aqueous solution with early strength and quick hardening properties is sprayed onto the surface of extruded products to remove defective products, thereby curing the good products quickly and increasing the pallet turnover rate (
For example, Japanese Patent Application Laid-Open No. 2-48478).

However, this method can only early harden the surface of the shaped body, and cannot uniformly harden the entire body.

Therefore, even if it is cured early, it requires great care to remove from the pallet, which is still impractical.

[Problems solved by the invention]

In view of the above-mentioned problems, the present invention has been made with the object of providing a method for molding inorganic building materials, which allows early hardening of the entire molded product and also allows safe return of defective products.

[Technology to solve problems]

That is, the method for forming an inorganic building material of the present invention uses cement, silica sand, fibrous material, methyl cellulose, and
In a mixture for extrusion molding of inorganic building materials such as water, 20% or more of the cement is replaced with a thermosetting inorganic molding material having a high content of calcium aluminate and sulfuric anhydride, and after extrusion molding the mixture, It is characterized by primary curing at a curing temperature higher than the curing temperature of the thermosetting inorganic molding material.

[Effect]

The cement mixture used in this invention is the same as the conventional extrusion molding mixture, and there is no particular point to note regarding the ingredients and amounts themselves.

In this invention, more than 20% of the cement added to the cement formulation is replaced with a thermosetting inorganic molding material with a high content of calcium aluminate and sulfuric anhydride.

This thermosetting inorganic molding material is used under high temperature conditions (e.g. 60°C).
(above), it exhibits a very early hardening property, but at low temperatures (e.g. 30°C to 60°C) it takes a long time to harden compared to ordinary Portland cement. When it is added by replacing it with , the desired early strength effect can be obtained according to the amount added if the temperature conditions are set at a constant yield.

Conversely, if the temperature is kept below a certain level, the curing speed will be the same as that of ordinary Portland cement, and no curing will occur in the extruder even if defective products are returned.

Therefore, if only a non-defective extrusion molded product is subjected to primary curing at a temperature higher than that at which the early strength effect can be obtained, the early strength of the entire molded product will be exhibited.

In addition, in the present invention, the above-mentioned thermosetting property is not 8! The reason why the replacement amount of the quality molding material is 20% or more relative to the cement is that if it is less than this, the desired early strength effect cannot be obtained.

Note that there is no restriction on increasing the amount, and the entire amount of cement may be replaced.

[Example] Next, this invention will be explained in detail.

Example 1 In a conventional extrusion compounding method in which 45% by weight of cement, 45% by weight of silica sand, 5% by weight of bentonite as a lubricant, and 5% by weight of bulb as a reinforcing fiber were added, of the 45% by weight of cement added, 18% by weight in thermosetting state I!
The molding material was replaced with a quality molding material (product name: rTSAJ, manufactured by Osaka Cement Co., Ltd.), and extrusion molding was performed according to a conventional method.

This extruded excipient was divided into two parts, one of which was heated to 60°C.
The first curing was performed under the following temperature conditions, and the other was left at room temperature (23°C).

The former cured in just 20 minutes and became completely handleable after 40 minutes.

On the other hand, the latter became completely usable after 6 hours.

Example 2 45% by weight of the total amount of cement in the cement mixture in Example 1 was replaced with a thermosetting inorganic molding material (product name: rTsAJ, manufactured by Osaka Cement Co., Ltd.), and the mixture was cured in the same manner as in Example 1.

As a result, those subjected to high-temperature curing were cured in just 10 minutes, and could be completely handled after 30 minutes.

On the other hand, the latter became completely usable after 6 hours.

Next, the shaped bodies obtained in Example 1 and Example 2 were subjected to primary curing at 80° C. for 2 hours, and the bending strength and surface hardness (Brinnell hardness) were measured, and the results shown in Table 1 were obtained.

Table 1 As explained above, according to the present invention, in inorganic extrusion molding, by selectively curing only good products at high temperature, handleable strength can be obtained very quickly, and the pallet rotation rate can be improved accordingly. be able to.

In addition, the curing speed is almost the same as that of ordinary Portland cement unless primary curing is performed at high temperatures, so it has the effect of preventing clogging in the extruder even if the material is returned.

In Table 1, Comparative Example 1 had a replacement amount of 4.
5% by weight, and Comparative Example 2 shows one in which no substitution was made.

As is clear from Table 1, it was confirmed that Examples 1 and 2 developed strength very early.

〔effect〕

Claims (1)

[Claims] (1) Cement, silica sand, fibrous materials according to conventional mixing methods,
In a compound for extrusion molding of inorganic building materials such as methyl cellulose and water, after replacing 20% or more of the cement with a thermosetting inorganic molding material having a high content of calcium aluminate and sulfuric anhydride, and extruding the compound. . A method for molding an inorganic building material, characterized in that primary curing is performed at a curing temperature higher than the curing temperature of the thermosetting inorganic molding material.