JP2001206762A - Calcium silicate-based formed body excellent in frost damage resistance and workability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a calcium silicate-based formed body showing performance nearly equal to that of the usual formed body in strength, manufacturable at inexpensive cost enough to be used for general purpose and excellent in lightweight property and incombustibility as well as frost damage resistance and workability. SOLUTION: Portland cement of 20-27 wt.%, unslaked lime of 13-18 wt.% in terms of slaked lime or 13-18 wt.% slaked lime, 43-50 wt.% silicate-based material consisting of diatomaceous earth and 20 wt.% or more silicate-based hollow body, 4-9 wt.% perlite, 4-7 wt.% pulp and 0.2-1 wt.% organic fiber are mixed with an adequate amounts of a mixing agent and water to prepare slurry. The slurry is dehydrated and formed by press to manufacture a formed body and then the formed body is annealed and dried in an autoclave to obtain the objective formed body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a calcium silicate molding having excellent frost damage resistance and processing characteristics, which is used as an interior or exterior material of a building.

[0002]

2. Description of the Related Art Calcium silicate moldings as building materials are required to have light weight, frost resistance, workability, dimensional stability during processing, and nonflammability, and are inexpensive as building materials. Is required. Means for imparting these required properties include, for example, perlite as an inorganic lightweight aggregate, glass balloon, and polystyrene beads as an organic lightweight aggregate in order to reduce the water absorption of the molded body, improve the frost resistance, and reduce the weight. The use of various lightweight aggregates such as polyvinylidene chloride balloons, polypropylene balloons, phenol balloons, polyurethane foams, and ethylene vinyl acetate has been studied.

[0003] However, these lightweight aggregates include:
It did not satisfy the above-mentioned plurality of required characteristics required for a molding material for a building material such as an exterior material. For example, except for pearlite, it is too expensive to be used as a general-purpose building material, and organic lightweight aggregates are flammable, so that they do not give satisfactory compacts in nonflammability. Aggregate also does not give compacts that exhibit sufficient frost damage resistance.

[0004]

DISCLOSURE OF THE INVENTION The present invention exhibits the same level of performance as conventional products in terms of strength properties, and is excellent in frost damage resistance and workability, which can be manufactured at a cost that can be used for general purposes. It is an object of the present invention to provide a calcium silicate-based molded article which is excellent in lightness and incombustibility as well as being lightweight.

[0005]

Means for Solving the Problems The present inventors have found that diatomaceous earth, which has been conventionally used as an inorganic lightweight aggregate, impairs the frost damage resistance, and examined alternatives. The present inventors have found that the use of a siliceous hollow body such as ash beads (hereinafter referred to as CF beads) provides a molded body that has solved the above-mentioned problems, and has completed the present invention. That is, the present invention provides 20 to 27% (% by weight,
13-18% of quicklime or slaked lime in terms of Portland cement and slaked lime in the same manner), 43-50% of diatomaceous earth and siliceous hollow body, and 20% by weight of siliceous hollow body
The above siliceous material, 4-9% pearlite, 4-7
% Pulp, 0.2 to 1% of organic fibers, an appropriate amount of an admixture and water are mixed to form a slurry, and then the slurry is dewatered and molded by a press to produce a molded body. The present invention relates to a calcium silicate-based molded article obtained by curing and drying in an autoclave and having excellent frost damage resistance and processing characteristics. Hereinafter, the present invention will be described in detail.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the used amount of Portland cement is 20 to 27% (% by weight, hereinafter the same). If the amount of Portland cement is less than 20%, the durability and bending strength of the product will decrease. On the other hand, when the amount of Portland cement is larger than 27%, not only the specific gravity of the product is increased, but also the workability such as nailing and sawing is reduced. As the Portland cement, Portland cement having ordinary, high strength, ultra-high strength, moderate heat, sulfate resistance, low heat and the like can be used, but use of normal Portland cement is sufficient.

[0007] Diatomaceous earth is used as the siliceous raw material, and CF beads or shirasu balloons are used as the siliceous hollow body. The siliceous hollow bodies can be used alone or as a mixture. Use of silica powder is not preferred in terms of product weight reduction. In addition, CF beads are hollow spherical particles made of calcium silicate, which are produced by heating and foaming fly ash, and various sizes are commercially available, and the commercially available products can be used. In order to achieve both of the maintenance of frost resistance and the improvement of frost damage resistance, it is preferable to use those having a particle size of 20 to 300 μm. On the other hand, the shirasu balloon is a hollow spherical particle which is produced by heating and expanding shirasu and is mainly composed of calcium silicate similarly to CF beads.

[0008] Quick lime or slaked lime is converted into 13 to
When 18% is used, the total amount of diatomaceous earth and CF beads or the total amount of silicate expressed by the total amount of diatomaceous earth and shirasu balloon is set to 43 to 50%. If the silicic acid mass is less than 43%, the amount of the silica source for forming calcium silicate will be insufficient, and the bending strength of the product will be reduced. On the other hand, if the mass of silicic acid exceeds 50%, unreacted silica components will be present as defects in the molded body, and the bending strength of the product will be small and brittle.

The replacement ratio of diatomaceous earth by CF beads or shirasu balloon is 20 to 60%, preferably 30 to 5%.
It should be in the range of 0%. When the replacement ratio of diatomaceous earth by CF beads or shirasu balloon is less than 20%,
The effect of improving the frost damage resistance was not sufficiently exhibited, while the replacement rate was 6%.
If it is larger than 0%, not only the bending strength of the product is lowered, but also the production cost is increased, which is not preferable.

[0010] Quick lime or slaked lime is calcium hydroxide (stimulant) generated by the hydration reaction of Portland cement.
To make up for the shortage and contribute to the pozzolanic reaction with diatomaceous earth. The amount of quicklime or slaked lime is 13 to 18% in slaked lime conversion.

The amount of pearlite added is 4 to 9%. Since pearlite plays a role of a filter aid in the step of reducing the weight of the product and the slurry dehydration molding step, if the amount of pearlite is small, delamination tends to occur during dehydration molding, and a product having a predetermined specific gravity cannot be obtained. On the other hand, if the addition amount is too large, material separation is likely to occur, and pearlite floats on the upper surface of the slurry, and when pressed as it is, not only the appearance of the product surface is impaired, but also a product having a predetermined specific gravity and bending strength is obtained. Disappears.

In the present invention, pulp and organic fibers other than pulp are further added in order to improve the strength and reduce the weight of the product. The pulp is prepared by mixing the previously defibrated pulp with water,
Used as pulp-water mixture. As the pulp, it is preferable to use hemp pulp or sisal pulp in view of strength properties. If the amount of pulp added is small, the nail pull-out resistance and nailing of the product, and the workability such as sawing are reduced.
Since the nonflammability of the product is impaired, the amount is set to 4 to 7%.

As the organic fibers, commercially available ordinary fibers can be used, but naturally, those excellent in strength are preferred for the purpose of addition. In order to improve the effect of addition, those having good dispersibility are preferable, and those which withstand autoclave curing under an alkaline atmosphere are preferable. Fibers satisfying this condition include polypropylene fibers and acrylic fibers. The added amount of the organic fiber is set to 0.2 to 1%. If the amount is too small, no sufficient effect of addition is exhibited, and if it is too large, the nonflammability of the product is reduced.
The fiber length of the organic fiber used in the present invention is 3 to 20 m
m, preferably in the range of 6 to 12 mm, makes it possible to obtain a molded product which is not only excellent in mixing with inorganic materials but also excellent in characteristics.

In the production of the calcium silicate-based molded product of the present invention, in addition to the above-mentioned component raw materials, an AE agent, an AE water reducing agent, a high-performance water reducing agent and the like generally used in the production of cement products. Are used alone or in combination. When used alone,
The AE agent is 0.05 to 0.15%, the AE water reducing agent is 0.2 to 1%, based on the total weight of the slurry raw material excluding the water and the admixture,
The high performance water reducing agent is 0.5-3%.

The first step of producing the calcium silicate-based molded article of the present invention is a step of preparing a slurry by mixing raw materials with water. In this step, a predetermined amount of pulp and water are mixed to prepare a pulp-water mixture having a pulp concentration of about 2%, and then a predetermined amount of Portland cement, quicklime or slaked lime, diatomaceous earth is added to the pulp-water mixture. Add CF beads, perlite, organic fiber and admixture to 3 ~
Mix for 5 minutes to prepare a slurry. The molding is performed by press molding, but the slurry is transferred to a press molding machine and a molding pressure of 2
Press molding is performed at 0 to 40 kg / cm ² for 60 to 180 seconds to produce a molded body. The molded body after molding is taken out from the press molding machine, and is allowed to stand for 20 hours or more.
Curing is performed by an autoclave at 80 ° C. under a pressure of 5 to 10 kg / cm ² for 4 to 8 hours. The culture is 100
The product is dried at -120 ° C for 24 hours or more to produce a product, generally a plate-like, calcium silicate-based molded product.

[0016]

EXAMPLES Examples and Comparative Examples Specific examples are shown below.
The calcium silicate-based molded product of the present invention will be described in more detail. (1) Composition 3.5 kg of hemp pulp is added to 170 liters of water, and about 2%
A consistency pulp-water mixture was prepared. The pulp-water mixture is transferred to a mixing tank, and a small amount of commonly used additives such as ordinary Portland cement, slaked lime, diatomaceous earth or diatomaceous earth + diatomaceous earth replacement material, perlite, polypropylene fiber, and an admixture are added and mixed with stirring. , To prepare a slurry. The ratio of each component is usually Portland cement:
About 25%, slaked lime: about 16%, diatomaceous earth or diatomaceous earth + diatomite replacement material: about 44%, perlite: about 8%, hemp pulp: about 7%, and polypropylene fiber: about 1%, The ratio for each case is as shown in Table 1. Diatomaceous earth having an average particle diameter of 23 μm is used, and CF beads (particle diameter of 80 to 100 μm) are used as a replacement material.
m), silica fume (particle size: 0.1 to 0.2 μm), E
VA powder (particle diameter 0.3 mm or less) was used. These are all commercial products. Diatomaceous earth replacement ratio X by replacement material
(%) Indicates that the ratio of the diatomaceous earth-substituted material in the whole material is 44 * X / 100% by weight.
EVA, which is a hollow spherical particle composed of ethylene and a vinyl acetate copolymer, is not a siliceous hollow body, but is shown in the SiO ₂ component column for convenience in the table.

As an additive, an AE agent (trade name: Vinsol, manufactured by Yamamune Chemical Co., Ltd.) was used in an amount of 0.1% by weight based on the total weight of the slurry raw material excluding water and the additive.

[0018]

[Table 1]

(2) Molding Here, a method for producing a molded body for evaluation of mechanical properties and a freeze-thaw test will be described, and a method for producing a molded body for workability evaluation will be described later. The slurry was transferred to a 100-t press molding machine and pressed at a molding pressure of 40 / cm ² for 60 seconds to obtain a molded body. The molded body taken out of the molding machine is
After standing at room temperature for 24 hours, the autoclave curing was performed at 180 ° C. and 10 kg / cm ² for 5 hours.
Dry at 24 ° C for 24 hours, 320mm x 320mm x 20m
m was obtained.

(3) The mechanical properties of the molded body were measured according to the following method. -Bulk specific gravity: JIS A5418-Bending strength: JIS A1408-Hardness: JIS Z2117-Tensile strength: JIS Z5536 The results of the mechanical property evaluation are shown in Table 3.

(4) The freeze-thaw test was performed according to the ASTM C666A method as shown in Table 2. The results of the freeze-thaw test are shown in FIG.

[0022]

[Table 2]

(5) Evaluation of workability For workability, a workability test using a molding machine and a workability test using an NC router were performed. The workability test with a molder was performed using a 1200t press to form 1020 mm x 3100 mm x 20 mm
The molded body was cut into a standard product having the shape shown in FIG. 2 using a molder (manufactured by Kuwahara Seisakusho), and the number of workable parts was measured. The cutting conditions are as follows: Shaft rotation speed: 6000 rpm
m, feed speed: 10 m / min. The workability test by the NC router was performed by cutting a molded body formed by the above-described method into a width of 500 mm × length of 2900 mm.
mm board, using an NC router (manufactured by Shoda Iron and Steel), rotation speed: 1000 rpm, feed speed: 4
Under a cutting condition of m / min, a groove having a width of 12 mm, a depth of 10 mm and a length of 60000 mm shown in FIG.
The blade wear was measured. Table 4 shows the workability evaluation results.

[0024]

[Table 3]

[0025]

[Table 4]

As shown in FIG. 1, by replacing diatomaceous earth with the alternatives shown here, the rate of thickness change associated with the freeze-thaw cycle is reduced, ie, the frost damage resistance is improved. In the CF beads, the frost resistance improved with an increase in the diatomite replacement ratio, and with a 20% replacement, a commercially available extruded plate known as a product having excellent frost damage resistance was shown as a comparison. Gives the same degree of frost damage resistance. Silica fume is also C
It shows the same effect as F beads. On the other hand, the effect of improving the frost damage resistance of EVA is inferior to CF beads and silica fume.

The mechanical properties and processing properties are also affected by the diatomaceous earth replacement material. In the case of CF bead replacement, the tensile strength is slightly reduced, but it is within a range in which there is no problem in practical use. Although the mechanical properties are improved by the silica fume replacement, as described later, this improvement leads to a reduction in processing properties, and also serves as a negative factor in weight reduction. EVA 20%
In the replacement product, not only the bending strength tends to decrease but also the EVA itself is expensive, so that the material cost is significantly increased as compared with the CF bead replacement, which is not preferable in this respect.

The CF bead substitute shows excellent processing characteristics in all the items measured this time. On the other hand, the replacement of silica fume causes a decrease in processing characteristics due to an increase in hardness, and does not solve the problem of the present invention.

[0029]

The calcium silicate-based molded article of the present invention has significantly improved frost damage resistance and processing properties as well as the conventional calcium silicate-based molded article. I have. Also, the mechanical properties show values comparable to those of conventional products. That is, the molded article of the present invention has made it possible to provide a building interior / exterior plate that requires good processing characteristics as well as durability.

[Brief description of the drawings]

FIG. 1 shows the results of a freeze-thaw test.

FIG. 2 shows a standard product shape cut and manufactured by a molder at the time of workability evaluation.

FIG. 3 shows a method of groove processing by an NC router in workability evaluation.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C04B 14:08 C04B 14:08 14:16 14:16 14:18 14:18 16:02 16:02 Z 16:06 16:06 18:14 18:14 Z 20:00) 20:00) A 111: 76 111: 76 (72) Inventor Masaaki Nagai 1-6 Okiyama, Kogushi-ji offing, Ube City, Yamaguchi Prefecture Ube Mitsubishi Cement Research Institute Ube Center F-term (reference) 4G012 PA05 PA07 PA11 PA24 PB03 RA03 4G054 AA01 AA14 AC04 4G056 AA18 AA19

Claims (2)

[Claims] 1. Silicate comprising 20 to 27% (weight%, the same applies hereinafter) of Portland cement, 13 to 18% of quicklime or slaked lime in terms of slaked lime, 43 to 50% of diatomaceous earth and siliceous hollow body A siliceous material with 20% or more hollow bodies, 4-9% pearlite, 4-7% pulp, 0.2%
A slurry is prepared by mixing 繊 維 1% of organic fiber, an appropriate amount of an admixture and water, and then the slurry is dewatered and molded by a press to produce a molded article. The molded article is further subjected to autoclave curing and drying. Calcium silicate moldings with excellent frost damage resistance and processing characteristics. 2. The calcium silicate molding according to claim 1, wherein the silicate hollow body is a CF bead and / or a shirasu balloon.