JPH0723245B2 - Calcium silicate compact - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is lightweight, has high strength and good dimensional stability, and is uniformly water-repellent to the inside, and is nonflammable and heat resistant. The present invention also relates to a calcium silicate molded body suitable for building materials such as outer wall materials.

<Prior art> Generally, outer wall materials are required to have excellent heat retention / heat insulation properties and high durability, but in recent years it has been newly found that they are lightweight, high strength, non-combustible, and non-asbestos. It has been demanded.

In terms of non-combustible and non-asbestos, fiber reinforced cement type, such as GRC (glass fiber reinforced cement), CF
There are materials such as RC (carbon fiber reinforced cement).

However, cement-based cements generally have a high bulk density of 1.6 to 2.0, and even low ones have a bulk density of around 1.0. Therefore, considering the construction aspect, it is necessary to reduce the thickness of the board, resulting in a lack of solidity and design. There is a problem.

Also, in terms of light weight, although there is ALC (lightweight foam concrete), due to structural defects caused by bubbles, high strength is not exhibited and the performance of the outer wall material is still insufficient.

On the other hand, although the material mainly composed of calcium silicate can generally control the bulk density to reduce the weight, the weight reduction of the product causes an increase in the essential porosity, and once water is absorbed, the thermal conductivity increases. In addition to causing a significant increase in heat insulation and heat insulation, fatal problems such as freezing and thawing may occur in cold regions.

<Problems to be Solved by the Invention> Therefore, development of a high-strength calcium silicate compact having water repellency has been demanded.

Generally, in order to make a calcium silicate compact water-repellent, for example, a method is known in which a surface of the calcium silicate compact is brush-coated with a water-repellent agent containing alkali methyl siliconate and then dried.

However, in such a conventional method, the surface water repellency is not yet sufficient, and the surface newly formed by cutting, breakage, etc., which is carried out at the construction site for dimension matching, etc. Since it was necessary to apply a water-repellent agent to the surface and dry it, it was extremely inconvenient because it took time and effort for construction.

<Means for Solving Problems> As a result of intensive studies in view of such problems, the present inventors have mixed calcium silicate hydrate with a specific rubber latex, a reinforcing material, and a water repellent. , By molding
The inventors have found that these problems can be solved and arrived at the present invention.

That is, the object of the present invention is to reduce the weight, high strength, and
An object of the present invention is to provide a calcium silicate compact which is excellent in non-combustibility and heat resistance and which is evenly water-repellent to the inside. The purpose is to provide calcium silicate hydrate, carboxyl group, and / or
Alternatively, a styrene-butadiene copolymer latex containing a carboxylic acid ester group, a reinforcing material, and a water-repellent agent are added, mixed, molded, and dried to obtain a calcium silicate molded body, which is a molded body of the molded body. It is easily achieved by a calcium silicate compact characterized by having a water absorption amount specified by JIS-Z2104 of 0.02 g / cm ³ or less.

Hereinafter, the present invention will be described in detail.

The calcium silicate hydrate used in the present invention is obtained by subjecting a calcareous raw material, for example, quick lime, and a siliceous raw material, for example, silica stone, to a hydrothermal synthesis reaction. Usually, from crystalline ones called xonotlite and tobermorite, CSHI,
CSHII and even amorphous ones can be widely used.

As its manufacturing method, calcareous raw material and siliceous raw material are CaO.
A method is employed in which an aqueous slurry adjusted so that the molar ratios of SiO ₂ and SiO ₂ are almost equal to each other is heated to 160 ° C. or higher under pressure and reacted. In the present invention, this slurry can be used as it is, but can also be used by adding water to a powder obtained by drying. The solid content concentration of calcium silicate hydrate in the slurry is not particularly limited,
10% or less is preferable, especially considering productivity, 3-8%
Is preferred.

The styrene-butadiene copolymer latex containing a carboxyl group and / or a carboxylic acid ester group is an unsaturated compound having a carboxyl group such as butadiene, styrene and acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid and crotonic acid. Compound, or C1-C1
4, preferably a carboxylate group having an alkyl group having 1 to 3 carbon atoms, specifically, a compound having a carboxylate group such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, etc. Is produced by a usual emulsion polymerization method. At that time, the molar ratio of the monomers is adjusted to a ratio of styrene: butadiene = 4 to 8: 6 to 2, and the unsaturated compound having a carboxyl group and / or a carboxylic acid ester group is added to the styrene and butadiene monomers. For 100 parts by weight in total,
The proportion is 0.2 to 20 parts by weight, preferably 0.2 to 15 parts by weight. If the addition amount of the unsaturated compound having a carboxyl group and / or a carboxylic acid ester group is too small, the flexural strength of the molded product will be reduced. On the other hand, if the addition amount is too large, problems such as cost increase occur.

The styrene-butadiene copolymer latex containing a carboxyl group and / or a carboxylic acid ester group is 2 to 25 in terms of solid content based on 100 parts by weight of calcium silicate hydrate.
It is preferable to add parts by weight. When the amount of addition is increased, the strength of the obtained molded product is improved, but on the other hand, problems such as a decrease in incombustibility, an increase in bulk specific gravity and an increase in cost occur.

Next, the water repellent used in the present invention usually has a viscosity at 25 ° C of 0.5 to 10 ¹⁰ centistokes, preferably 10 ²
~ 10 ⁸ cm Stokes is used.

Specifically, SH-200 (trade name, Toray Silicone Co., Ltd.
, Dimethylpolysiloxane), KF-54 and KF-99 (trade names, Shin-Etsu Chemical Co., Ltd., methylphenylpolysiloxane and methylhydrogenpolysiloxane), SF-8418 (trade name, Toray Silicone Co., Ltd. ), Methylcarboxypolysiloxane), modified dimethylpolysiloxane having OH groups at both ends, aminomethylpolysiloxane, and the like.

In the present invention, the water repellent agent can be used as a tatex emulsion mixed with the copolymer latex, but an emulsion emulsified with an ordinary surfactant may be used.

In addition, SH-490, SM-8701 and SM, which are commercially available as emulsions of dimethylpolysiloxane or its derivatives.
-7060 (trade name, manufactured by Toray Silicone Co., Ltd., both are anion emulsions of dimethylpolysiloxane),
SM-8706 (trade name, Toray Silicone Co., Ltd., dimethylpolysiloxane both terminal OH group modified anion emulsion)
Etc. can also be used advantageously.

The amount of the water repellent added is, relative to 100 parts by weight of calcium silicate hydrate, 20 parts by weight or less in terms of solid content, preferably,
It is recommended to add 1 to 15 parts by weight. The larger the amount added,
The water repellency of the molded article is improved, but if it is too large, the nonflammability and heat resistance are lowered, and the mechanical strength is also lowered.

As the reinforcing material, a fibrous reinforcing material is usually used for the purpose of further improving the bending strength of the molded product. The fibrous reinforcing material is not particularly limited, but for example, asbestos, pulp, glass fiber, pitch-based or PAN-based carbon fiber, rayon, nylon, polyester, vinylon, poloethylene, aramid fiber and the like are used.

The fibrous reinforcing material may be coated with a thermoplastic resin, a thermosetting resin, rubber latex or the like.

The form of the fibrous reinforcing material may be any shape, but in terms of handling and moldability, the fiber length is 1 to 50 mm,
Preferably, chopped fiber of 10 to 30 mm is used.

The addition amount of the fibrous reinforcing material is not particularly limited, but is usually 30% by weight or less of the molded product, and is preferably 10% by weight or less in consideration of water-based property and moldability.

In order to produce the molded product of the present invention, first, after mixing the copolymer latex and the water repellent, when added to the aqueous slurry of calcium silicate hydrate, added together with the reinforcing material,
Mix evenly. At that time, a polymer flocculant for a polymer emulsion such as polyacrylic amide may be added.

The aqueous chiller thus obtained is dehydrated by a method such as overpressurization, pressure-molded, and then dried to obtain a molded body.

As the molding method, press molding, papermaking molding, extrusion molding,
A known molding method such as vacuum molding can be used. The drying temperature after molding is usually 100 to 180 ° C., preferably 10
It is 5 to 150 ° C., and the drying time is usually 5 to 15 hours.
If the drying temperature is too low or the drying time is too short, water remains, resulting in a decrease in bending strength and an increase in shrinkage of the molded product. On the other hand, if the drying temperature is too high or the drying time is too long, the molded body becomes hard and the toughness of the molded body is impaired.

Thus, it is possible to obtain a calcium silicate compact which is lightweight, has high strength, is excellent in noncombustibility and heat resistance, and is uniformly water-repellent to the inside.

<Example> Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

The bending strength of the molded product was measured according to JIS A1408. The size of the test body was 15 cm × 5 cm × 1.5 cm, and the results are shown as an average value of three test bodies.

Further, the water absorption of the molded product in the present invention was measured according to JIS Z2104.

Example 1 Quicklime (CaO: 96.2%) 49.6 warm water was added to the parts by weight hydrated consumption, and slaked lime slurry, silica in the slurry (SiO ₂ 9
6.4%) 50.4 parts by weight are added, and the total amount of water is 27.5 based on the solid content.
Water was added to make the weight twice, and this slurry was added at 15 kg / cm ²
The reaction was carried out under water vapor pressure for 4 hours to obtain zonotolite calcium silicate hydrate.

To 100 parts by weight of the dry solid of calcium silicate hydrate, 7 parts by weight of a carboxyl-modified styrene-butadiene copolymer latex (Nippon Zeon: “Nipo1” 2570 × 5) and a water repellent (dimethylpolysiloxane) were added. Toray Silicone: SH200) 5 parts by weight was added and mixed for 5 minutes with a homomixer. Then, with this mixed liquid, as a fibrous reinforcing material,
3 parts by weight of carbon fiber (18 mm long) was added to the calcium silicate hydrate slurry and sufficiently dispersed.

Then, inject this slurry into a 300 mm × 300 mm mold,
It was pressure dehydrated and dried at 120 ° C. for 10 hours.

Table 1 shows the test results of the obtained molded product.

Example 2 Table 1 shows the test results of a molded article obtained in the same manner as in Example 1 except that the amount of the water repellent added was increased to 7 parts by weight.

Example 3 Table 1 shows the test results of a molded product obtained in the same manner as in Example 1 except that glass fiber (18 mm long) was used instead of carbon fiber.

Example 4 A test result of a molded article obtained in the same manner as in Example 1 is shown except that an emulsion obtained by emulsifying a water repellent agent with an anionic surfactant (manufactured by Kao: "Neoperex" F25) is used. 1
Shown in.

Example 5 Table 1 shows the test results of a molded product obtained in the same manner as in Example 4, except that the amount of the water repellent added was increased to 7 parts by weight in terms of solid content.

Comparative Example 1 A slurry of calcium silicate hydrate obtained in the same manner as in Example 1 was poured into a mold as it was, and a molded product was obtained in the same manner as in Example 1 below. Table 1 shows the test results of the obtained molded product.

Comparative Example 2 Table 1 shows the test results of the molded product obtained in the same manner as in Example 3 except that the carboxyl-modified styrene-butadiene copolymer latex and the water repellent were not added.

Comparative Examples 3 and 4 Table 1 shows the test results of the molded articles obtained in the same manner as in Examples 1 and 3 except that the water repellent was not added.

<Effects of the Invention> The calcium silicate compact of the present invention has excellent flexural strength while being lightweight, and is not only excellent in noncombustibility, heat resistance and water resistance, but also excellent in heat insulation and heat retention, and, It is known to have a humidity control function equivalent to that of wood, and it is extremely useful as a building material that replaces wood.

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Claims (7)

[Claims] 1. A styrene-butadiene copolymer latex containing a carboxyl group and / or a carboxylic acid ester group, a reinforcing material and a water repellent are added to an aqueous slurry of calcium silicate hydrate, mixed and dried. The resulting molded article, the water absorption amount specified in JIS-Z2104 of the molded article
A calcium silicate compact characterized by having a content of 0.02 g / cm ³ or less. 2. The calcium silicate compact according to claim 1, wherein the water repellent is dimethylpolysiloxane and / or its derivative. 3. A styrene-butadiene copolymer latex containing a carboxyl group and / or a carboxylic acid ester group is contained in an amount of 2 to 25 parts by weight in terms of solid content based on 100 parts by weight of calcium silicate hydrate. The calcium silicate compact according to claim 1. 4. An unsaturated hydrocarbon compound containing a carboxyl group and a styrene-butadiene copolymer latex containing a carboxyl group and / or a carboxylic acid ester group, the carboxyl group-containing unsaturated hydrocarbon compound per 100 parts by weight of the styrene-butadiene copolymer.
It is obtained by copolymerizing 2 to 20 parts by weight.
The calcium silicate compact described. 5. Dimethylpolysiloxane and / or its derivative is 1 to 1 with respect to 100 parts by weight of calcium silicate hydrate.
The calcium silicate compact according to claim 2, which is 5 parts by weight. 6. The calcium silicate compact according to claim 1, wherein the reinforcing material is an organic fiber or an inorganic fiber. 7. The calcium silicate compact according to claim 6, wherein the inorganic fibers are carbon fibers.