JPH11292606A - Production of inorganic cured article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relatively simple method for producing an inorganic cured article having a high strength, excellent toughness and excellent water resistance, and scarcely changing the dimension on the absorption of water. SOLUTION: This method for producing an inorganic cured article comprises adding reinforcing fibers, a filler, slaked lime or Portland cement and water to a mixture comprising water granulated slag and calcined gypsum in a weight ratio of 3:7 to 6:4 as main raw materials, dehydrating and molding the obtained slurry, curing the molded article with steam, and further curing the molded article at a high temperature. Thus, the inorganic cured article having excellent flexural strengths on a dry time and a water-absorbed time and scarcely changing the dimension on the absorption of water can be produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a building material,
The present invention relates to a method for producing an inorganic cured product having high strength, excellent toughness, excellent water resistance, and small change in water absorption dimension.

[0002]

2. Description of the Related Art Conventionally, as a method for producing an inorganic cured product used as a building material, slag, calcined gypsum or hemihydrate gypsum is used as a main raw material, and water is added to a mixture obtained by adding reinforcing fibers and the like to a slurry. A method is known in which the slurry is formed, the slurry is subjected to dehydration molding, and then cured and cured.

For example, Japanese Patent Publication No. 2-42754 discloses that
The calcined gypsum and the slag are mixed in a weight ratio of 2: 8 to 8: 2, and the obtained mixture is mixed with an alkaline substance, an aluminum sulfate-containing substance and a setting retarder, and then mixed.
A method for producing an inorganic cured product having excellent fire resistance, dimensional accuracy, flexibility and bendability by adding and mixing fibers and water, then molding the mixture, and subsequently curing under heat and moisture is disclosed. .

[0004]

However, the inorganic cured product produced by the method described in the above publication is
Although useful because it has the above-mentioned excellent properties and properties close to those of wood with high strength, there is a problem that the dimensional change upon water absorption is large. Further, other conventional inorganic cured products mainly made of slag and gypsum also have disadvantages in any of properties such as strength, toughness, water resistance, change in water absorption and the like, and have a volume expansion during curing. And the physical properties deteriorated.

Accordingly, an object of the present invention is to provide a method for producing an inorganic cured product having high strength, excellent toughness, excellent water resistance, and small change in water absorption by a relatively simple process. is there.

[0006]

Under such circumstances, the present inventors have conducted intensive studies and as a result, those having a specific range of the ratio of ettringite and gypsum, which are the main components of the inorganic cured product, have the above-mentioned excellent properties. To show various properties, and the ratio of this ettringite to gypsum, the mixing ratio of granulated slag and calcined gypsum of the main raw material in a specific range, the main raw material and reinforcing fiber, filler, slaked lime or Portland semester The present invention was found to be obtained by performing a two-stage curing under specific conditions after dewatering and forming a slurry containing a slurry and water, and completed the present invention.

[0007] That is, the present invention uses a mixture of granulated slag and calcined gypsum in a weight ratio of 3: 7 to 6: 4 as a main raw material,
A method for producing a cured inorganic material, characterized in that a slurry obtained by adding reinforcing fiber, slaked lime or Portland cement and water thereto is subjected to dehydration molding, then steam curing, and further steam curing at a higher temperature. It is.

Further, the present invention provides a mixture of granulated slag and calcined gypsum having a weight ratio of 3: 7 to 6: 4 as a main raw material, and a reinforcing fiber, a filler, slaked lime or Portland cement and water. An object of the present invention is to provide a method for producing a cured inorganic material, characterized in that the added slurry is subjected to dehydration molding, steam curing, and then steam curing at a higher temperature.

Further, the present invention relates to a reinforcing fiber comprising 4 to 9% by weight of wood pulp, 0.2 to 3% by weight of organic synthetic fiber, and 5 to 30% by weight of wollastonite as a filler.
It contains slaked lime or Portland cement in an amount of 0.5 to 5% by weight, and the weight ratio of granulated slag to plaster of Paris is 3: 7 to 6: 4.
A method for producing an inorganic cured product, characterized in that a mixture of water is added to the remainder, and a slurry obtained by adding water thereto is subjected to dehydration molding, followed by steam curing, and further steam curing at a higher temperature. .

Further, the present invention relates to a reinforcing fiber comprising 4 to 9% by weight of wood pulp and 0.2 to 3% of organic synthetic fiber.
5% by weight, wollastonite and calcium silicate hydrate as a filler are 5 to 35% by weight in total, 20% by weight or less of the calcium silicate hydrate, and 0.5 to 5% by weight of slaked lime or Portland cement. %, And a mixture in which the weight ratio of granulated slag and calcined gypsum is 3: 7 to 6: 4 is used as a balance, and a slurry obtained by adding water to the mixture is subjected to dehydration molding, then steam curing, and then further curing. An object of the present invention is to provide a method for producing an inorganic cured product, which has been subjected to steam curing at a high temperature.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the production method of the present invention, the weight ratio of the granulated slag and the plaster of Paris as the main raw materials is in the range of 3: 7 to 6: 4 because the ratio of the calcined gypsum in the main raw materials is low. If it exceeds 70% by weight, the amount of ettringite generated by steam curing is reduced, and the water resistance of the obtained inorganic cured product is reduced. Further, the ratio of the granulated slag is 60% by weight.
This is because, when the ratio exceeds 1, the amount of ettringite generated increases, and the dimensional change in water absorption increases. As calcined gypsum, desulfurized gypsum is heated to 90 to 160 ° C. to reduce the amount of water of crystallization to 2.5.
It is preferable to use one adjusted to ~ 6.2%.

Examples of the reinforcing fiber include glass fibers such as wood pulp, alkali-free glass, low alkali glass, and alkali-resistant glass; steel fibers such as iron-based and stainless steel;
Inorganic fibers such as asbestos and rock wool; organic synthetic fibers such as carbon fiber, aramid fiber, vinylon fiber, acrylic fiber, polypropylene fiber, nylon fiber, etc., of which wood pulp and vinylon fiber are particularly preferred. These fiber lengths are not particularly limited, and can be appropriately selected in consideration of workability, processability and strength of the cured product, and the like. These reinforcing fibers can be used alone or in combination of two or more.

Incorporation of reinforcing fibers contributes to the moldability and shape retention during dehydration molding of the cured product, and also improves the properties of the cured product, such as bending characteristics and toughness. The compounding amount is 4 to 12% by weight in a mixture of the main raw material excluding water, reinforcing fiber, filler, slaked lime or Portland cement (hereinafter, sometimes referred to as “mixing reference mixture”), preferably wood pulp. It is a combination of 4 to 9% by weight and 0.2 to 3% by weight of organic synthetic fibers. The mixability of woody pulp improves the moldability, especially during dewatering, and the mixability of organic synthetic fibers improves the toughness. Further, by blending an organic resin such as a vinyl acetate emulsion in an amount of 0.5 to 5 parts by weight in terms of solid content with respect to 100 parts by weight of the blending reference mixture, the toughness of the inorganic cured product can be further improved.

[0014] As the filler compounded as required,
Examples include wollastonite and mica, and fibrous wollastonite is particularly preferable. The blending amount of wollastonite is preferably 5 to 30% by weight in the blending reference mixture. Moldability at the time of dehydration molding is particularly improved by blending wollastonite.
In order to adjust the density of the obtained inorganic cured product, calcium silicate hydrate can be used in combination as a filler.
As the calcium silicate hydrate, for example,
What forms spherical secondary particles synthesized by a hydrothermal reaction as disclosed in Japanese Patent No. 16786 can be used. When wollastonite and calcium silicate hydrate are used in combination as a filler, the total of both is preferably 5 to 35% by weight, and the content of calcium silicate hydrate is preferably 20% by weight or less. The blending amount of slaked lime or Portland cement is preferably 0.5 to 5% by weight in the blending reference mixture. Slaked lime or Portland cement is blended to promote the production of ettringite, but a small amount in the above range can provide an appropriate amount of ettringite.

In the present invention, the main raw material, the reinforcing fiber,
The method for forming the slurry composed of the filler, slaked lime or Portland cement and water is not particularly limited, and each raw material can be mixed in an arbitrary order. First, the weight ratio of the granulated slag and the calcined gypsum is 3: Preferably, a mixture of 7 to 6: 4 is prepared, the mixture is mixed with a filler and slaked lime or Portland cement, and then reinforcing fibers and water are added to form a slurry. The amount of water to be added depends on the molding method, and the amount of water suitable for the molding method may be appropriately selected. Subsequently, the slurry is dewatered.

The dehydration molding method is not particularly limited.
Any known method can be applied, and examples thereof include a pressure molding method and a papermaking method. After molding, the density can be increased by pressing. At the time of dehydration molding, it is preferable to add a small amount of a coagulant such as a polyacrylamide-based polymer coagulant to the slurry in that the drainage can be improved.

After the dehydration molding, the following two stages of steam curing are performed. That is, first, the first steam curing is performed, and then the second steam curing at a higher temperature is performed after the first steam curing. As the curing conditions, it is preferable that the first steam curing condition is 5 to 40 ° C. for 1 to 48 hours, and the high temperature steam curing condition performed thereafter is 50 to 90 ° C. for 6 to 96 hours. In addition, the first steam curing condition was set to 15
More preferably, the temperature is set to 1 to 6 hours at ２５25 ° C., and the high-temperature steam curing conditions performed thereafter are set to 48 to 72 hours at 60 to 80 ° C. By performing such two-stage steam curing, dihydrate gypsum is sufficiently generated by relatively low-temperature primary steam curing, and then an appropriate amount of ettringite is generated by high-temperature secondary steam curing. Thus, it is possible to suppress the expansion of the molded product during curing, to obtain a cured product having high strength, excellent water resistance, and a small change in water absorption dimension. Further, by adding the setting retarder, the working life of the slurry can be extended, and the time from preparation of the slurry to molding can be given a margin. Examples of the setting retarder include alkali citrate, alkali succinate, sodium phosphate, peptone, gelatin, and amino acid derivatives, and one or more of these can be used in combination.

The cured inorganic material obtained by the method of the present invention is obtained by dispersing a reinforcing fiber and a filler uniformly in a matrix mainly composed of ettringite and gypsum dihydrate of acicular crystals. The X-ray diffraction intensity (E) of the (100) plane (d = around 9.70 angstroms) and the X-ray diffraction intensity (N) of the (021) plane (d = around 4.28 angstroms) of gypsum dihydrate Ratio E /
N is in the range of 0.03 to 0.50. X
The X-ray diffraction intensity refers to the peak height from the baseline of the X-ray diffraction spectrum. Such an inorganic cured product has characteristics of high strength, excellent toughness and water resistance, and small change in water absorption dimension. Specifically, the bulk density is 1.0 to 1.70,
The dimensional change in water absorption is 0.15% or less.

According to the method of the present invention, a slurry containing a specific mixture of granulated slag and calcined gypsum, a reinforcing fiber, a filler, a small amount of slaked lime or Portland cement, and a slurry containing water are subjected to the first dewatering and forming. Gypsum (CaSO ₄・ 2H ₂ O) is sufficiently generated from calcined gypsum in the steam curing, and the calcium hydroxide in the dihydrate gypsum and granulated slag is further heated in the second steam curing. CaO) and aluminum oxide (Al ₂
The reaction with O ₃ ) can be appropriately performed. For this reason, ettringite (3CaO.Al ₂ O ₃ .3CaSO ₄ .31 to 32H ₂
The amount of O) produced can be made an appropriate amount, and the expansion of the molded body during curing can be suppressed, and an inorganic cured body having physical properties suitable as a building material can be produced.

[0020]

Next, the present invention will be described in more detail with reference to examples, but this is merely an example and does not limit the present invention. Examples 1 to 6 and Comparative Examples 1 to 4 According to the amounts shown in Tables 1 and 2, the main raw material, the reinforcing fibers,
Compounding filler, slaked lime and vinyl acetate emulsion,
Water and a small amount of set retarder were added and mixed to form a slurry. Next, the pressure molding method (dehydration molding pressure: 50 kg / cm ² )
To obtain a sheet-like material. At the time of dehydration molding, a small amount of a polyacrylamide polymer compound was added as a coagulant. The sheet was cured under the steam curing conditions shown in Tables 1 and 2, and dried to obtain an inorganic cured product of the present invention. Tables 1 and 2 show physical properties of the obtained inorganic cured product.

[0021]

[Table 1]

[0022]

[Table 2] 1) Degassing gypsum is heated to 105 ° C. to reduce the amount of water of crystallization to 5.0%.
Adjusted to. 2) Degassing gypsum is heated to 150 ° C to reduce the amount of water of crystallization to 3.5%.
Adjusted to. 3) Bending strength x breaking strain

From Table 1, it can be seen that the cured inorganic materials of the examples have excellent flexural strength and flexural toughness both when dry and when absorbing water.
It can be seen that the water absorption dimensional change is small. Also, from Table 2,
Comparative Examples 1 and 2 in which the first-stage steam curing was omitted, and Comparative Example 3 in which the blended amount of the granulated slag was about 74% by weight in the main raw material were inferior in the water absorption dimensional change rate. Comparative Example 4, in which the amount of calcined gypsum is about 72% by weight, is inferior in bending strength when absorbing water.

[0024]

According to the present invention, a cured inorganic material having high strength, excellent toughness, excellent water resistance and small change in water absorption can be obtained as a building material by a relatively simple method.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C04B 14:38 16:06 18:14)

Claims (5)

[Claims] 1. The weight ratio of granulated slag to calcined gypsum is 3: 7 to
6: 4 mixture as a main raw material, which contains reinforcing fibers,
A method for producing a cured inorganic material, comprising dehydrating a slurry containing slaked lime or Portland cement and water, followed by steam curing, and then steam curing at a higher temperature. 2. The weight ratio of granulated slag to calcined gypsum is 3: 7 to 2.
6: 4 mixture as a main raw material, which contains reinforcing fibers,
A method for producing a hardened inorganic material, comprising: dehydrating a slurry containing a filler, slaked lime or Portland cement and water, then subjecting to steam curing, and then steam curing at a higher temperature. 3. The reinforcing fiber is 4 to 9% by weight of wood pulp and 0.2 to 3% by weight of organic synthetic fiber. The filler is 5 to 30% by weight of wollastonite and 0 to 100% of slaked lime or portland cement. The mixture containing 0.5 to 5% by weight and having a weight ratio of granulated slag to calcined gypsum of 3: 7 to 6: 4 was used as a balance, and a slurry obtained by adding water to the mixture was subjected to dehydration molding and then steam-cured. And a steam curing at a higher temperature. 4. A reinforcing fiber comprising 4 to 9% by weight of wood pulp and 0.2 to 3% by weight of organic synthetic fiber, and a filler comprising wollastonite and calcium silicate hydrate in a total of 5 to 5%. 35% by weight of the calcium silicate hydrate
0% by weight or less, slaked lime or Portland cement
The mixture containing 5 to 5% by weight and the weight ratio of the granulated slag to the plaster of Paris is 3: 7 to 6: 4, and the slurry obtained by adding water thereto is subjected to dehydration molding and then steam curing. And a method for producing a cured inorganic material, wherein the cured material is steam-cured at a higher temperature. 5. The first steam curing condition is 5 to 40.degree.
~ 48 hours, and then the high temperature steam curing condition is 5
The method for producing an inorganic cured product according to any one of claims 1 to 4, wherein the heating is performed at 0 to 90 ° C for 6 to 96 hours.