JPH06127992A - Cement composition for extrusion molded article - Google Patents

Abstract

PURPOSE:To improve appearance and dimensional accuracy by compounding cellulose powder of specific average grain sizes and high-performance water- reducing agents into a cementitious material. CONSTITUTION:The cellulose powder having 2 to 100mum average grain sizes is compounded at 10 to 10wt.% of the entire part of the compd. into the cementitious material, such as Portland cement, and >=1 kinds of the high- performance water-reducing agents among condensation product of naphthalene sulfonate and formaldehyde, polycarboxylate, refined lignin sulfonate and polystyrene sulfonate, is compounded at 0.6 to 3.0wt.% into the cement. Others, such as various kinds of intimate mixtures including lightweight aggregate, reinforcing fibers, surfactants, retardants, blast furnace slag, stone powder, etc., are compounded and kneaded into the above-mentioned compsn. at prescribed ratios, by which the cement compsn. for extrusion molded articles is obtd. This compsn. is then extruded by an extrusion molding machine mounted with a die at the front end, by which the molded structural body having the quality of excellent appearance and dimensional accuracy is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement composition for extrusion molding, and more particularly to a cement composition suitable for extrusion molding of a water-kneaded product containing a cementitious material as a main raw material. .

[0002]

2. Description of the Related Art A cement plate body, a cement-asbestos body, etc. obtained by extrusion molding a water-kneaded product containing a cementitious material as a main raw material with a die having a desired shape is available. It is used for exterior wall materials, roof materials, floor materials, etc. of buildings.

However, since the water-kneaded material of cementitious material has low shape retention and water retention even if it is extruded as it is, slippage in the cylinder or die of the extruder is poor,
Moreover, the mold release property at the die exit is poor. Therefore, a product having a smooth surface cannot be obtained, resulting in a molded product that does not match a predetermined shape.

Conventionally, in order to solve these problems, water-soluble polymers such as methyl cellulose, hydroxymethyl cellulose and carboxymethyl cellulose have been used (for example, JP-A-61-256957), and it is necessary to add these additives. Thus, plasticity is imparted to the water-kneaded product of the cementitious material, and the shape retention of the molded product is improved.

However, in the case of these additives, the tackiness is too large, the slipperiness and the releasability are inferior, and the extrusion speed becomes small. Moreover, the smoothness of the surface of the molded product is inferior, and it is the current situation that a product having a satisfactory shape cannot be obtained. Further, since the water-soluble polymer has a retardation of hardening with respect to cement, the development of strength is significantly delayed, and there is a problem in productivity.

[0006]

SUMMARY OF THE INVENTION In view of the above problems, the present inventors have made earnest studies and, as a result, did not include substances such as thickeners and water-soluble polymers that cause retardation of curing, and did not contain cellulose powder and high performance. By incorporating a water-reducing agent as a basis, it has been possible to complete a cement composition suitable for extrusion molding.

That is, the present invention relates to a cement composition for extruded bodies, which comprises a cellulose powder and a high-performance water reducing agent.

Since the cellulose powder in the cement composition of the present invention has a high water-retaining capacity and a large slipperiness, it improves the physical properties of sliding in the cylinder and the die of the extruder during the extrusion molding process and the die release at the die exit. It is extremely excellent in sex.

Further, the high-performance water reducing agent in the cement composition of the present invention is effective for increasing the rate of decrease in the amount of water in the cement composition and accelerating the development of strength. Therefore, strength can be expressed in a short time, which is effective for improving productivity. Furthermore, the presence of the high-performance water-reducing agent facilitates the mixing of the cellulose powder and the respective materials such as cement, silica sand, fibers, and water, and enables uniform mixing in a short time.

Cellulose powder used in the present invention is usually commercially available, for example, trade name Celltop (Co., Ltd.).
Kojin Co., Ltd., trade name KC Flock (manufactured by Sanyo Kokusaku Pulp Co., Ltd.), trade name Avicel (manufactured by Asahi Kasei Co., Ltd.) and the like are used.

Cellulose powder having an average particle diameter of 2 to 100 μm is particularly effective for sliding physical properties and water retention. It is actually difficult to manufacture particles having an average particle size of less than 2 μm, and those having an average particle size of 100 μm or more have insufficient sliding physical properties and water retention.

[0012] The amount of cellulose powder in the cement composition of the present invention may be in the range that imparts plasticity to the water-kneaded product of the cementitious material, and is not limited, but 1 to 10% by weight based on the entire system. Preferably, 2 to 5% by weight is more preferable. If the amount added is excessive, the viscosity becomes high and the extrusion speed is reduced.

As the high-performance water reducing agent in the present invention, naphthalene sulfonate formaldehyde condensate (for example, Mighty 150; manufactured by Kao Corporation), melamine sulfonate formaldehyde condensate (for example, Mighty 1)
50V-2; manufactured by Kao Corporation, polycarboxylic acid or ester or salt thereof (for example, Tupol HP-
8; Takemoto Yushi Co., Ltd.), purified ligninsulfonic acid or a salt thereof (for example, Sanflow HP-500; Sanyo Kokusaku Pulp Co., Ltd.), polystyrene sulfonate (for example, Glarion S-100; Lion). Co., Ltd.), a formaldehyde condensate or cocondensate having a phenol and / or anilinesulfonic acid skeleton (for example,
Paric FP-200S; manufactured by Fujisawa Pharmaceutical Co., Ltd., and the like are used.

The amount of the high-performance water-reducing agent added is not particularly limited as long as an appropriate viscosity can be obtained from the viewpoint of workability, but is preferably 0.6 to 3.0% by weight as an active ingredient with respect to the cement.

The cementitious material of the cement composition used in the present invention includes ordinary Portland cement,
Blast furnace cement or fly ash cement may also be used.

Further, those containing various admixtures (agents) added in addition to the cementitious material are also applicable. As an example, asbestos, glass fiber, polypropylene fiber, vinylon fiber, various fibers such as aramid fiber, perlite, lightweight aggregates such as vermiculite, blast furnace slag, fly ash, silica fume, stone powder, silica sand, bentonite, expansive material , Surfactants, retarders, early-strengthening agents and the like.
It is also possible to add a small amount of water-soluble polymers.

[0017]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 The materials used are shown below.・ Ordinary Portland cement: Chuo Cement Co., Ltd. ・ Toyoura standard sand: From Toora ・ Vinylon fiber: AB1200 × 6 semi-hard (Unitika Ltd.) ・ Clay: Kaolin ・ Cellulose powder: Trade name Celltop (Co., Ltd.) Particle size was adjusted. Symbol S-1: Average particle size 3.5 μm Symbol S-2: Average particle size 21.3 μm Symbol S-3: Average particle size 44.2 μm Symbol S-4: Average particle size 92.5 μm Symbol S-5: Average particle size 123.2 μm・ High-performance water reducing agent: The water reducing agent was selected and implemented. Symbol K-1: Mighty 150; manufactured by Kao Corporation Symbol K-2: Mighty 150V-2; manufactured by Kao Corporation Symbol K-3: Tupole HP-8; manufactured by Takemoto Yushi Co., Ltd. Symbol K- 4: Sanflow HP-500; Sanyo Kokusaku Pulp Co., Ltd. code K-5: Glarion S-100; Lion Co., Ltd. code K-6: Palic FP-200S; Fujisawa Yakuhin Co., Ltd.
Manufactured by-Comparative water-soluble polymer Symbol H-1: Methylcellulose (Metroose 60SH,
(Made by Shin-Etsu Chemical Co., Ltd.) Molding properties and strength characteristics of the composition of the present invention in which a cellulose powder and a high-performance water reducing agent are blended by using the basic formulation shown in Table 1 and a comparative composition (with addition of methyl cellulose) Table 2
Shown in.

The molding conditions are as follows: The cement composition is mixed by a kneader (MHS-80 type, manufactured by Miyazaki Tekko Co., Ltd.) to prepare a kneaded product, and extrusion molding is performed with a die having a width of 60 mm and a thickness of 8 mm attached to the tip. Machine (Made by Miyazaki Iron Works, FM-3
An extruded plate was manufactured by the 01 type.

Table 2 shows the extrusion speed at the time of manufacturing, the molding properties of the molded plate manufactured (the evaluation criteria are shown below) and the bending strength.
Shown in. Molded plate evaluation criteria ○: Surface smoothness, no scratches △: Slight scratches on the surface occurred ×: Many streaky scratches on the surface Evaluation criteria for dimensional accuracy ○: Width / thickness error 0.1 mm △: Width, Thickness error 0.1 mm to 0.3 mm x: Width and thickness error 0.3 mm or more The length of the molded body per extrusion speed of 1 minute was measured. Bending strength According to JIS-R5201 Bending test method of mortar Strength after 24 hours

[0021]

[Table 1]

[0022]

[Table 2]

* 1;% by weight based on the whole system * 2;% by weight based on cement (effective content) * 3; Symbol H-1 (Metroses 60SH) 0.1% by weight based on cement (effective content)

[0024]

EFFECT OF THE INVENTION By extruding the cement composition of the present invention, it is possible to obtain a molded structure of excellent quality in terms of appearance and dimensional accuracy, and it is possible to improve productivity because the strength is rapidly expressed. The moldings produced according to the invention can be used in all applications of building structures. Moreover, although researches on buried molds have recently started, they can be used for these applications.

Claims (3)

[Claims] 1. A cement composition for an extrusion molded article, which comprises cellulose powder and a high-performance water reducing agent. 2. Cellulose powder has an average particle size of 2 to 100 μm.
The cement composition for extruded products according to claim 1, wherein the cement composition is m. 3. The high-performance water reducing agent is a naphthalene sulfonate formaldehyde condensate, a melamine sulfonate formaldehyde condensate, a polycarboxylic acid or its ester or its salt, a purified lignin sulfonic acid or its salt, a polystyrene sulfonate, Phenol and /
Alternatively, it is a formaldehyde condensate or cocondensate having an aniline sulfonic acid skeleton, and the cement composition for an extrusion molded body according to claim 1.