JP2565612B2 - Asbestos-free cement composition for extrusion molding - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an asbestos-free cement composition for extrusion molding used as a building civil engineering material.

[0002]

2. Description of the Related Art In general, ceramic products mainly composed of cement are widely used as building civil engineering materials. Among them, the extrusion-molded cement board is highly evaluated as a high-performance outer wall material having a dense structure and freezing damage resistance.

Conventionally, as has been found in, for example, Japanese Patent Application Laid-Open No. 55-124605, a large amount of asbestos is generally compounded in an extrusion molding cement composition. The reason is that asbestos itself is excellent in strength characteristics, fire resistance, and alkali resistance, and particularly in extrusion molding, due to the excellent water retention of asbestos, the cement composition is soft even in a relatively high water content. It is possible to smoothly extrude without becoming too much,
In addition, the molded body does not lose its shape after extrusion, that is, asbestos imparts good extrusion moldability and water retention to the cement composition. Further, asbestos is inexpensive, and asbestos has been conventionally mixed up to about 20% on a solid content basis.

However, with regard to the use of this asbestos, there is a risk of a health hazard due to dust in recent years, and there has been a strong demand for non-asbestos in building materials.

[0005] In order to deal with this, various techniques for making asbestos-free cement compositions for extrusion molding have been studied, but until now, in addition to asbestos, it has such an improvement effect on extrusion molding, and has strength characteristics and fire resistance. However, an inexpensive alternative material having excellent performance in alkali resistance has not been found alone, and, for example, in JP-A-3-45545, cement, blast furnace slag fine powder, siliceous raw materials, etc. are mixed. C in the total component
In an extrusion molding cement composition mainly composed of a bonding cement mixture having a molar ratio of aO / SiO ₂ adjusted to about 0.7 to 1.2, the pulp content is 0.5 based on the solid content of the blending raw material. Disclosed is an asbestos-free cement composition for extrusion molding, which is characterized in that: ~ 3% by weight, mica flakes: 3-10% by weight, the balance being the associative cement mixture, containing no asbestos at all.

[0006]

As described above, a material other than asbestos is used to impart good extrusion molding and shape retention to a cement composition to enable extrusion molding, and the obtained extrusion molding. It has already been disclosed that a cement building material having excellent strength and fire resistance can be obtained by curing the body, and the same or higher performance as that of the conventional asbestos-used extrusion-molded cement board was obtained. Such an asbestos-free cement composition is slightly inferior in extrusion performance to an asbestos product, and thus it is necessary to improve the production stability of the cement composition.

Therefore, the object of the present invention is to provide a building material which does not use asbestos at all, has a performance in extrusion molding comparable to that of asbestos products, and has higher performance than conventional extrusion-molded asbestos cement boards. It is an object of the present invention to provide an asbestos-free asbestos cement composition for extrusion molding.

[0008]

Since there is no single material that has the excellent performance of asbestos, the present inventors also have a plurality of performances as in the invention of JP-A-3-45545. Attempted to substitute with materials, 3 to 10% by weight of mica flakes and 0.5 to 0.5 of pulp based on the solid content of the blended raw materials.
It was found that an asbestos-free cement composition for extrusion molding containing 3% by weight and 3 to 30% by weight of wollastonite is suitable for producing an asbestos-free cement board having performance required as a building material.

That is, the asbestos-free asbestos cement composition for extrusion molding according to the present invention is prepared by mixing cement, blast furnace slag fine powder, siliceous raw material and the like, and CaO / SiO 2 in the total components thereof.
_{In a} cement composition for extrusion molding, which comprises a binding cement mixture in which the molar ratio of ₂ is adjusted to about 0.7 to 1.2 as a main binder, the pulp content is 0.5 based on the solid content of the blending raw material.
˜3% by weight, mica flakes 3 to 10% by weight, wollastonite 3 to 30% by weight, the balance being the cementitious cement mixture.

Furthermore, the asbestos-free asbestos cement composition for extrusion molding according to the present invention is prepared by mixing cement, blast furnace slag fine powder, siliceous raw material and the like, and CaO / SiO 2 in the total components thereof.
_{In a} cement composition for extrusion molding, which comprises a binding cement mixture in which the molar ratio of ₂ is adjusted to about 0.7 to 1.2 as a main binder, the pulp content is 0.5 based on the solid content of the blending raw material.
.About.3% by weight, mica flakes 3 to 10% by weight, wollastonite 3 to 30% by weight, lightweight aggregate 3 to 20% by weight, and the balance being the associative cement mixture.

[0011]

The function of the asbestos-free asbestos cement composition for extrusion molding of the present invention is
Mica flakes are 3 to 10% by weight, pulp is 0.5 to 3.0% by weight, wollastonite is 3 to 30% by weight, and asbestos is not contained at all, based on the solid content of the blended raw materials. .

As described in Japanese Patent Laid-Open No. 3-45545, mica flakes have high strength, fire resistance, and
As an alternative to alkali resistance and lubricity, it has already been found that pulp substitutes the water retention and shape retention properties of asbestos, but naturally, pulp has low tensile strength,
Since it has high hygroscopicity and deteriorates fire resistance, it is desirable that the blending ratio of pulp be as small as possible. However, according to the experiments conducted by the present inventors, it was found that even if the pulp content was reduced to 0.5%, extrusion molding was possible.
The most stable production is possible within the range of ~ 2% by weight, but if the pulp content is too small, the water retention capacity is insufficient and the cement composition becomes too soft, resulting in poor extrusion performance and molding after extrusion. Insufficient body shape retention.

As the type of pulp used in the present invention, any of waste paper pulp, hardwood pulp and softwood pulp can be applied. However, since waste paper pulp and hardwood pulp have a soft texture, they are suitable for uniform mixing.

Mica flakes replace the high strength, fire resistance, alkali resistance and lubricity of asbestos. The longitudinal elastic modulus of mica exceeds that of asbestos, and has intrinsic composite reinforcing performance superior to that of asbestos. In addition, since the shape is thin, it is easy to uniformly disperse in the powder, and since the specific surface area is large, a wide interface to be joined with cement can be secured.

Here, the amount of the mica flakes mixed is 3 to 10.
Weight% When the amount of mica flakes is less than 3% by weight, it is difficult to impart sufficient strength to the product building material, and when it exceeds 10% by weight, a uniform mixed state with cement cannot be obtained. Not good for There are no particular restrictions on the type of mica flakes in terms of chemical composition, crystal structure, etc., and any of muscovite, phlogopite, biotite, leukomica, soda mica, and synthetic mica are applicable.

Further, in the present invention, wollastonite is blended in addition to pulp and mica flakes. As described above, mica flakes are added to supplement the high strength, fire resistance, alkali resistance, and lubricity of asbestos, but by adding wollastonite, water retention and shape retention are improved. Therefore, the extrusion property is better than that of the conventional wollastonite-free product, and the reinforcing effect of the wollastonite itself also has the effect of improving the product strength.

Further, by adding wollastonite, it becomes possible to increase the amount of compounding water as a function which is considered to contribute from the shape of wollastonite to the cement composition hydro-kneaded, that is, the water content necessary for improving the extrusion performance. Can be added more. Further, unlike mica, it has a needle-like shape, so that it can be easily oriented during extrusion molding even if the addition amount exceeds 10% by weight. It was also found that the uncured shape extruded from the mold was superior to that without wollastonite. That is, wollastonite is also effective for maintaining the shape of the extruded material. The addition of wollastonite contributes to the improvement of extrusion performance, so that defective products can be reduced in production. This is of great significance in making the extrusion method non-asbestos, which is relatively difficult to improve production efficiency. By the way, as the extrudability is improved, the physical properties are naturally improved. Further, due to the synergistic effect with the reinforcing property of wollastonite, it has been possible to establish a higher quality asbestos-free cement composition for extrusion molding than in the past.

Further, conventionally, organic fibers such as pulp have been mainly used for water retention and shape retention, but by using wollastonite together, the addition amount thereof can be further reduced. This further improves the non-combustibility of the extruded material. In addition, since wollastonite itself has high heat resistance (melting point 1544.5 ° C.), addition of wollastonite can exert a function as a heat resistant filler, which leads to improvement of material performance. By improving the nonflammability and heat resistance, the safety of the building material can be further improved as compared with the conventional composition. It is possible to provide an extruded plate having fireproof performance closer to that of an asbestos-based material in the true sense. However, to improve quality, add 30% by weight
Even if the above is added, no dramatic improvement in quality is observed with the increase in the amount added, so the amount of wollastonite added is 30
The upper limit was weight%. If the added amount of wollastonite is less than 3% by weight, the effect of addition is not exhibited, so the lower limit was made 3% by weight.

Next, cement, blast furnace slag fine powder, siliceous raw material, etc. are mixed and CaO / S in the total components thereof is mixed.
The associative cement mixture in which the molar ratio of iO ₂ is adjusted to about 0.7 to 1.2 is not particularly novel and includes all cements that have been generally used in extrusion molding. . For example, the cement used for this may be any one of Portland cement, blast furnace cement, fly ash cement, or a combination of two or more thereof, and further, in various cases such as blast furnace slag fine powder or siliceous raw material added thereto. There can be The addition of blast furnace cement and blast furnace slag fine powder enhances the long-term strength of building materials,
Addition of fly ash cement or siliceous raw material may help strengthen the product in the autoclave curing process.

Further, in the cement composition for extrusion molding, a small amount of additives other than asbestos, for example, 2% or less of extrusion aid (methyl cellulose etc.), 3% or less of reinforcing fiber such as carbon fiber, ceramic fiber, Inorganic fibers such as glass fibers, organic fibers such as rayon, vinylon, nylon, polypropylene, hemp, and cotton, and other pigments, paints, surface active agents, water-reducing agents and the like can be added for specific purposes. Even in these uses, the replacement of asbestos with mica flakes, pulp and wollastonite does not cause any problems which directly affect it.

Further, in order to reduce the weight of the asbestos-free asbestos cement composition for extrusion molding of the present invention, lightweight aggregates such as perlite, shirasu balloon, and lightweight sand containing fly ash as a main component can be used. The blending amount of these is 3 to 20.
It is within the range of weight%. If the blending amount is less than 3% by weight, the cement composition has little effect on weight reduction, and if it exceeds 20% by weight, the extrusion performance is deteriorated, which is not preferable.

[0022]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto. Examples 1 to 6 and Comparative Examples 1 to 2 In Table 1 below, compounding composition and compounding ratio (weight ratio based on solid content)
Indicates.

[0023]

[Table 1]

As shown in Table 1, a mixture having a compounding ratio is mixed by a mixer, kneaded by a kneader, and then formed into a hollow plate by a vacuum extrusion molding machine. After natural curing, 180 ° C. autoclave curing is performed for 6 hours to obtain a cured molded body. Table 2 below shows the extrusion moldability, surface properties, water retention, shape retention and physical properties of the extrusion molded plate based on the formulation of Table 1.

[0025]

[Table 2]

As shown in Table 1, the formulation water can be increased by the addition of wollastonite, so that
As shown in Table 2, the addition of wollastonite powder increased the permissible range as compared with the case where water retention and shape retention were not added. As a result, the extrusion performance was improved and the performance could be improved in terms of surface properties and strength. In addition, the heat resistance of Wollastonite can be exerted at the same time as the heat-resistant aggregate effect, and at the same time, it becomes possible to reduce the amount of pulp and organic fibers that have been conventionally used for maintaining water retention and shape retention, and the heat resistance is further improved.

[0027]

Industrial Applicability As described above, the asbestos-free asbestos cement composition for extrusion molding of the present invention does not use asbestos at all and the extrusion performance in terms of production is comparable to that of asbestos products. It is possible to provide a building material with higher performance than a cement board.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI technical display location C04B 14:38 18:14 14:16) (72) Inventor Masaaki Washida 204 Sumiyoshi-cho, Eniwa-shi, Hokkaido No. 2 (72) Inventor Zenritsu Takamiya 4-13-408, Tokodai, Ishioka-shi, Ibaraki (72) Inventor Seiichi Shimobayashi 1-12-18, Chiribetsu-cho, Muroran-shi, Hokkaido (72) Inventor Shita Nobuyuki Kuni No. 12 Nakamachi, Muroran, Hokkaido Nippon Steel Co., Ltd. Muroran Works

Claims (2)

(57) [Claims] 1. A mixture of cement, blast furnace slag fine powder, siliceous raw material, etc., and CaO / SiO 2 in the total components thereof.
_{In a} cement composition for extrusion molding, which comprises a binding cement mixture in which the molar ratio of ₂ is adjusted to about 0.7 to 1.2 as a main binder, the pulp content is 0.5 based on the solid content of the blending raw material.
An asbestos-free cement composition for extrusion molding, characterized in that: ~ 3% by weight, mica flakes: 3-10% by weight, wollastonite powder: 3-30% by weight, and the balance being the associative cement mixture. 2. A mixture of cement, blast furnace slag fine powder, siliceous raw material, etc., and CaO / SiO 2 in the total components thereof.
_{In a} cement composition for extrusion molding, which comprises a binding cement mixture in which the molar ratio of ₂ is adjusted to about 0.7 to 1.2 as a main binder, the pulp content is 0.5 based on the solid content of the blending raw material.
-3% by weight, mica flakes 3-10% by weight, wollastonite powder 3-30% by weight, lightweight aggregate 3-20% by weight, the balance being the cementitious cement mixture. Asbestos-free cement composition for molding.