JP2763929B2 - Method for producing high-strength calcium silicate compact - Google Patents

Description

The present invention relates to an economical method for producing a high-strength calcium silicate molded product.

(Conventional technology) Calcium silicate compacts obtained by hydrothermal synthesis of siliceous raw materials and calcareous raw materials are used as materials with excellent properties such as light weight, high strength, heat resistance, workability, etc. for building materials. Widely used.

The conventional methods for producing a calcium silicate molded body are roughly classified into (1) wet compression molding, (2) papermaking molding, and (3)
Semi-dry molding method, (4) extrusion molding method, and (5) cast molding method. However, problems have been pointed out in any of these molding methods.

That is, except for the cast molding method, the bulk density of the molded body obtained by any of these methods is limited to a certain narrow range, and in the wet compression molding method or the semi-dry molding method, a large press or Papermaking equipment was required. In addition, the extrusion molding method requires an extruding facility, so that the equipment cost is increased in each case, and the disadvantage that the manufacturing cost is increased has been pointed out. In the casting method, a raw material slurry is filled into a mold, and the raw material slurry is directly placed in an autoclave and heated and reacted under pressure to form the molded body. However, this method has another problem that a large number of molds are required for manufacturing.

In view of the above, US Pat. No. 2,432,981 discloses a technique for solving the above-mentioned drawbacks of the casting method and improving the rotation rate of the mold. This uses diatomaceous earth of amorphous silica as a siliceous raw material, lime, caustic soda and bentonite are added as a hardening agent, and a fibrous raw material and water are mixed, filled into a mold, heated and primary hardened. This is a method in which the mold is demolded, heated and reacted under pressure, and then dried. Also, in another U.S. Patent No. 2,904,444,
Amorphous silica diatomaceous earth is used as the siliceous raw material, and lime, anhydrous sodium silicate or anhydrous potassium silicate as a hardening agent, sugar as a hardening retardant are added thereto, and a slurry obtained by mixing a fibrous raw material and water is formed. A method is disclosed in which a frame is filled, heated and primary-cured, demolded, and then heated and reacted under pressure to dry. Certainly, according to these methods, although the primary cured product at the time of demolding has a hardness that can withstand handling, another problem that the strength of the final product heat-reacted under pressure is significantly reduced has arisen separately. . For this reason, what is obtained here cannot be used as it is for building materials.

(Problems to be Solved by the Invention) In the present invention, when a molded body of calcium silicate is cast by a casting method, the hardness of the primary molded body after demolding is made sufficiently resistant to handling, and the subsequent molding is performed. The strength of the final molded product obtained by the heating reaction under pressure is intended to obtain a high-strength calcium silicate molded product that can sufficiently withstand building materials.

(Means for Solving the Problems) The present invention relates to a raw material mixture containing at least a siliceous raw material, a calcareous raw material, a primary curing agent, and water, wherein crystalline silica and amorphous silica are used as the siliceous raw material. And the weight ratio of water / solid to amorphous silica / (crystalline silica +
The relationship between the weight ratio of amorphous silica) and points A (1.0, 0.50), B (1.0, 0.15), and C (4.0, 0.5) shown in FIG.
0), D (4.0, 0.60), and E (2.0, 0.60), within the range of a pentagon, and furthermore, sodium silicate or potassium silicate as a primary curing agent, and a mixture of a siliceous raw material and a calcareous raw material. A slurry is obtained by adding 0.5 to 3.0% based on the content, and then the slurry is filled in a mold, heated and primarily cured, then demolded, and then heated and reacted under pressure. A method for producing a high-strength calcium silicate molded product (Claim 1), a raw material mixture comprising a calcareous raw material, a siliceous raw material, a primary curing agent, a fiber, a heat-resistant resin, and water, The mixing ratio of the conductive resin is 2
Of crystalline silica and amorphous silica as siliceous raw materials, and the weight ratio of water / solid to the weight ratio of amorphous silica / (crystalline silica + amorphous silica) The relations are represented by points F (1.0, 0.25), G (1.0,
0.07), H (4.0, 0.45), and I (4.0, 0.55), within the range of a quadrangle, and sodium silicate or potassium silicate as a primary curing agent, and a mixture of calcareous material and siliceous material. A slurry is obtained by adding 0.5 to 3.0% based on the content, and then the slurry is filled into a mold, heated and primary-cured, and then released from the mold. In addition to sodium silicate or potassium silicate as a primary hardening agent, sodium silicate fluoride is added to the method for producing a high-strength calcium silicate molded product (claim 2) with respect to the total amount of the siliceous raw material and calcareous raw material. .
The method for producing a high-strength calcium silicate molded product according to claim 1 or 2, wherein the content is 1 to 1.5%. Hereinafter, these inventions will be further described. First, the invention of claim 1 will be described.

In the invention of claim 1, the main raw materials of the molded body are a siliceous raw material, a calcareous raw material, and a primary curing agent. In addition to the above, it is optional to use fibers or other reinforcing materials if necessary.

As the siliceous raw material, a combination of crystalline silica and amorphous silica in a special ratio as described below is used. Quartz is preferably used as the crystallized silica, and the particle size thereof is preferably fine so as to shorten the reaction time.
For example, it is preferable to adjust the particle size to 250% mesh sieve residue 10% or less. As the amorphous silica, diatomaceous earth,
Fluorite, silica flour and the like can be used, but diatomaceous earth is preferred, and the particle size is preferably 10 μm or less.

As the calcareous raw material, slaked lime, quick lime, lime milk obtained by digesting quick lime in water, or a mixture thereof is used. In this case, it is preferable to mainly use slaked lime or quick lime when the weight ratio of water / solid is less than 2.0, and to use mainly lime milk when the weight ratio of water / solid is 2.0 or more.

The mixing ratio of the siliceous raw material and calcareous raw material is CaO / SiO ₂
The molar ratio is preferably in the range of 0.7 to 1.1. Further, as the primary curing agent, sodium silicate or potassium silicate is used, and its addition rate is 0.5 to 3.0%. If it is less than 0.5%, there is no effect, and if it exceeds 3.0%, the strength of the final product formed by heat reaction under pressure is undesirably reduced. Reinforcing materials are optionally used as needed, and when they are blended, the strength of the product is improved. The type of reinforcing material is not particularly limited, but, for example, pulp fiber, nylon fiber,
Examples include, but are not limited to, inorganic fibers such as polyester fiber, rock wool, and asbestos. In order to make the building material nonflammable, the amount of the organic fiber used is preferably in the range of 0.5 to 5.0% based on the total amount of the siliceous raw material and the calcareous raw material.

Among the above blended raw materials, a particularly noteworthy point is a siliceous raw material. In the present invention, crystalline silica and amorphous silica are combined in a special ratio. However, it is preferable that the special compounding ratio of the crystalline silica and the amorphous silica of the present invention is changed by the weight ratio of water / solid in the raw material.

That is, as the weight ratio of water / solid of the raw material is increased to increase the hardness of the material obtained by pouring the raw material into the mold and hardening (primary curing agent), the non-silicone raw material is increased. It is necessary to increase the proportion of crystalline silica. On the other hand, in the present invention, the water / solid weight ratio of the raw material is preferably 1.0 to 4.0. If it is less than 1.0, the flowability of the raw material mixture is poor, and it is not suitable for casting. On the other hand, when the weight ratio of water / solid exceeds 4.0, it is necessary to greatly increase the amounts of the amorphous silica and the primary curing agent. However, in such a case, the strength of the final product is reduced, and a desired product cannot be obtained. However, even when the weight ratio of water / solid is in the range of 1.0 to 4.0, it is necessary to increase the proportion of amorphous silica as the weight ratio of water / solid increases as described above.

The inventors have performed a number of experiments and found that the water / solid weight ratio,
In the relationship between the ratio of crystalline silica and amorphous silica,
The hardness after primary curing of the molded article, the bending strength of the final product, and the like were examined. The experimental conditions in this experiment were as follows.

(Experimental conditions) The weight ratio of water / solid was selected in the range of 0.7 to 4.5. Crystalline silica, Toroiro silica stone 250 mesh sieve residue 0.1%
Diatomaceous earth of less than 50 μm was used as the amorphous silica. As the calcareous raw material, slaked lime powder having a 250 mesh sieve residue of 0.1% or less was used, and was blended so that the molar ratio of CaO / SiO ₂ became 0.8. 0.1% of sodium silicate (water glass No. 1) was added as a primary curing agent. Further, pulp (Canadian standard freeness 350 ml) was added as a reinforcing material, and 5% of the pulp was added thereto, and mixed with water. This raw material mixture is
The mold was filled in an epoxy resin mold which had been heated at 100 ° C. and had a size of 303 mm × 606 mm × height 12 mm, and the surface was made uniform.
This was put into a steam curing box, and saturated steam at 100 ° C. was blown into it, and kept at a slurry temperature of 90 ° C. for 20 minutes to release the primary cured product. The hardness of the primary cured product is measured using a rubber hardness tester (JIS
6301 Type A). The primary cured product was placed in an autoclave and reacted at a vapor pressure of 10 kg / cm ² and a temperature of 180 ° C. for an hour. Then, after dropping to atmospheric pressure and taking out from the autoclave, the adhered moisture was reduced to 5 in an oven at 105 ° C.
% To obtain a final product.

The results are shown in Tables 1 and 2 and FIG. It was considered that the strength of the final product should be determined in relation to the bulk density, and the specific strength was also determined. The results are shown in Tables 1 and 2.

Of the materials used in the various experiments shown in Tables 1 and 2, considering the use as building materials, the specific strength was 12%.
It is required to be 5 or more.

As long as the lower limit of the specific strength is 125, the relationship between the weight ratio of water / solid and the ratio of the amorphous silica to the content of the crystalline silica and the amorphous silica is represented by the point A (1.0, 0.5) shown in FIG.
0), B (1.0, 0.15), C (4.0, 0.50), D (4.0, 0.6)
0), it is necessary to be within the range of a pentagon surrounded by E (2.0, 0.60).

The raw materials as described above are kneaded with water and poured into a mold as a slurry, which is heated and cured in the mold by the action of the amorphous silica and the primary curing agent. The heating here is carried out at about 70 to 100 ° C.
It is preferred to heat at 0-100 ° C. for 20-30 minutes. By doing so, a primary curing agent that maintains self-holding power and does not hinder handling can be obtained, so that the mold can be released without hindrance. In this case, the degree of hardening is based on the fact that the hardened body does not have cracks, chipped corners, dents, or the like during handling of the hardened body. For that purpose, for example, as a simple measuring method, the hardness of the cured body is measured with a rubber hardness meter (JIS 6301 A type), and the indicated scale may be 30 or more.

After releasing the primary cured product, the primary cured product is placed in an autoclave and subjected to a heating reaction under pressure. The reaction is preferably performed at a pressure of 10 kg / cm ² or more and a temperature of 180 ° C. or more for 2 to 12 hours. After completion of the reaction, the product is taken out of the autoclave and dried to obtain a final product. Its absolute dry bulk density has a width of 0.2 to 0.7. In addition, potassium silicate can also be used as a primary curing agent, as can be seen from Examples 4 and 5 described below.

Next, the invention of claim 2 will be described. In this invention, the main raw materials are a siliceous raw material, a calcareous raw material, and a primary curing agent, as in the invention of claim 1. A siliceous material,
As the calcareous raw material, those described in the first aspect of the present invention are used substantially as they are.

That is, crystalline silica and amorphous silica are used as the siliceous raw material, and these are used after adjusting the required particle size. The mixing ratio of the crystalline silica and the amorphous silica in the siliceous raw material is changed according to the weight ratio of water / solid in the raw material. Are slightly different from the invention of claim 1 as described later.
The same applies to the calcareous material of the first aspect.

As the primary curing agent, sodium silicate or potassium silicate is used as in the first aspect of the invention.

In the present invention, in addition to these main raw materials, fibers and a heat-resistant resin are used as auxiliary raw materials.

The fibers are glass fibers, asbestos, rock wool, inorganic fibers such as needle-like wollastonite, fibrous sepiolite, and pulp fibers, carbon fibers, nylon fibers, vinylon fibers, and polyester fibers. It is effective for improvement. For this reason, it is preferable to use glass fibers for a part of the fibers used. The amount of the fibers used is preferably in the range of 2 to 10% by weight in terms of the mixing ratio in all the raw materials. If it is less than 2% by weight, desired effects such as strength and toughness of the obtained product cannot be obtained, and if it exceeds 10% by weight, the effect cannot be improved so much.

Acrylic resin, styrene resin,
It is a melamine resin, an ethylene vinyl acetate resin, a phenol resin, or a copolymer resin thereof. These resins are preferably used in an aqueous emulsion so that they can be uniformly mixed with other raw materials. Among them, an aqueous emulsion of an acrylic resin or an acrylic-styrene copolymer resin is preferable. The mixing ratio of the heat-resistant resin is preferably 2 to 10% by weight in terms of solid content. If it is less than 2% by weight, desired effects such as strength and toughness of the obtained product cannot be obtained, and if it exceeds 10% by weight, the effect cannot be improved so much. When the above fibers and resins are used, the mixing ratio of amorphous silica required to promote primary curing during molding can be reduced.

As already described, even in the invention of claim 2, the compounding ratio of crystalline silica to amorphous silica in the siliceous raw material varies depending on the weight ratio of water / solid in the raw material. This point is the same as the first aspect of the present invention. However, regarding the relationship between the blending ratio of crystalline silica and amorphous silica in the siliceous raw material and the weight ratio of water / solid in the raw material, the fiber and the heat-resistant resin are blended in the raw material. Therefore, it is different from the first aspect of the present invention.

In this regard, the inventor has conducted many experiments in the same manner as in the first aspect of the present invention, and found that the molded product after the primary curing in the relationship between the ratio of crystalline silica to amorphous silica and the weight ratio of water / solid. The hardness and bending strength of the final product were examined.
The experimental conditions for this experiment were as follows.

(Experimental conditions) The weight ratio of water / solid was selected in the range of 1.0 to 4.0. Crystalline silica is 0.1% of 250-mesh sieve residue of bird roof quartzite
Diatomaceous earth of less than 50 μm was used as the amorphous silica. As the calcareous raw material, slaked lime powder having a 250 mesh sieve residue of 0.1% or less was used, and was blended so that the molar ratio of CaO / SiO ₂ became 0.85. Sodium silicate (water glass No. 1) or potassium silicate as primary curing agent is 1.0% in terms of solid content
Was added. In addition, alkali-resistant glass fiber (diameter 13 μm, length 13 mm) 3.0% as a reinforcing material, acrylic-styrene copolymer resin emulsion (solid content 54.2%) as a heat-resistant resin
%, PH 9.0, anionic) was added in a proportion of 3.0% in terms of solid content, and mixed with water. This raw material mixture was filled in an epoxy resin mold having an inner size of 303 mm × 606 mm × height 12 mm, which had been heated at 100 ° C. in advance, to make the surface uniform. This was put into a steam curing box, and saturated steam at 100 ° C. was blown into it, and kept at a slurry temperature of 90 ° C. for 20 minutes to release the primary cured product. The hardness of the primary cured product was measured using a rubber hardness tester (JIS 6301 A type). This primary cured product was placed in an autoclave and reacted at a vapor pressure of 10 kg / cm ² and a temperature of 180 ° C. for 4 hours. Thereafter, the pressure was lowered to the atmospheric pressure, the product was taken out of the autoclave, and dried in an oven at 105 ° C. until the adsorbed water content became 1% or less to obtain a final product. The results are shown in Table 2 and FIG. The strength of the final product is
The specific strength was also determined and is shown in Table 2 and FIG. Regarding Nos. 7, 11, 17, 22, and 27, the physical properties were not measured because the fluidity of the raw material slurry was extremely poor, and the molding could not be performed by casting into a mold.

In FIG. 2, when the weight ratio of amorphous silica / (crystalline silica + amorphous silica) is higher than the line FI, the range in which the flowability of the raw material slurry decreases and the casting becomes difficult. It is. In the figure, the range below the line GH is a case where the primary hardness of the cured body is insufficient and handling becomes difficult.

Therefore, as shown in FIG. 2, in the invention of claim 2, since the fiber and the heat resistant resin are blended in the raw material, the weight ratio of water / solid and the amorphous silica The relationship between the weight ratio of (crystalline silica + amorphous silica) / (crystalline silica + amorphous silica) is shown by points F (1.0, 0.25), G (1.0, 0.07), H (4.0, 0.
45), it is necessary to be within the range of the rectangle enclosed by I (4.0, 0.55).

The raw material specified as above is kneaded with water to form a slurry, poured into a mold, heated and cured, and then demolded to obtain a primary cured product. The same is true. Next, the primary cured product is placed in an autoclave and reacted by heating under pressure. After the reaction is completed, the primary cured product is taken out of the autoclave and dried to obtain a product, which is also the same as the first aspect of the present invention.

The invention according to claim 3 is that, in addition to sodium silicate or potassium silicate as the primary curing agent, sodium silicate is further added in an amount of 0.1 to 1.5 with respect to the total amount of the siliceous raw material and the calcareous raw material.
%. Thereby, the strength of the final product can be further increased.

(Effects of the Invention) According to the present invention described above, the mixing ratio of crystalline silica and amorphous silica of the siliceous raw material, which is a part of the raw material used, is changed only by changing the relationship with the weight ratio of water / solid. It is possible to obtain a high-strength calcium silicate molded product in which the hardness of the primary cured product does not hinder handling and the strength of the final product is also high. Furthermore, according to the present invention, since the absolute dry bulk density of the final product can be set to a wide range of about 0.2 to 0.7, using the same device, various types of heat insulating materials, partition materials, wall materials, ceiling materials, etc. Building materials will be made.

Examples 1 to 3 As a siliceous raw material, Tori roof quartzite was used as crystalline silica.
A powder having a 250 mesh sieve residue of 0.1% and diatomaceous earth having a particle size of 50 μm or less as amorphous silica were used in a mixing ratio shown in Table 2. This siliceous material and 25
0 mesh sieve with slaked lime powder of 0.1% or less
It was blended so that the molar ratio of SiO ₂ was 0.9. 2.0% of sodium silicate (water glass No. 1) was added as a primary curing agent, and 3% of alkali-resistant glass fiber having a diameter of 9 μm and a length of 13 mm was added as a reinforcing material, and mixed with water. This raw material mixture was filled into an epoxy resin mold having an internal size of 910 mm × 1820 mm and heated to 100 ° C. in advance, and the surface thereof was made uniform. This was put into a steam curing tank, and saturated steam at 100 ° C. was blown into it, and kept at a slurry temperature of 90 ° C. for 20 minutes to remove it as a primary cured product. This primary cured product was placed in an autoclave and reacted at a vapor pressure of 10 kg / cm ² and a temperature of 180 ° C. for 10 hours. Thereafter, the pressure was lowered to the atmospheric pressure, taken out of the autoclave, and dried in an oven at 105 ° C. until the attached moisture became 5% or less to obtain a final product. Table 3 shows the hardness of the primary cured product and the physical properties of the final product.

Examples 4 to 5 The same procedure as in Examples 1 and 3 was carried out except that 2.0% of potassium silicate was added as a primary curing agent. This result is the fourth
It is shown in the table.

Examples 6 to 8 Sodium silicate (water glass No. 1) as a primary curing agent
The same procedure as in Examples 1 to 3 was carried out except that 2.6% and 0.4% of sodium silicofluoride were added. Table 5 shows the results.

It is recognized that when sodium silicate is added as a primary curing agent in addition to sodium silicate, the strength of the final product is increased as compared with the case of sodium silicate alone.

Examples 9 to 11 As siliceous raw materials, a powder of 250% sieve with a 250-mesh screen of a Tori roof type as a crystalline silica, and a diatomaceous earth of 50 μm or less as an amorphous silica were used.
They were mixed and used at the mixing ratios shown in the table. This siliceous raw material
250 mesh sieve with slaked lime powder of 0.1% or less
It was blended so that the molar ratio of O / SiO ₂ became 0.85. Furthermore, as a reinforcing material, alkali resistant glass fiber (diameter 13 μm, length 13
mm) 5.0%, and an acrylic-styrene copolymer resin emulsion (solid content: 54.2%, pH 9.0, anionic) as a heat-resistant resin, 5.0% in terms of solid content, was added in each of the internal proportions. Sodium silicate (water glass No. 1) as primary curing agent
% And mixed with water. This raw material mixture was filled into an epoxy resin mold having an inner size of 303 mm × 606 mm × height 15 mm, which had been heated to 100 ° C. in advance, and the surface thereof was made uniform. This was put into a steam curing tank, and saturated steam at 100 ° C. was blown thereinto, kept at a slurry temperature of 90 ° C. for 20 minutes, and primary cured and demolded. This primary cured product was placed in an autoclave and reacted at a vapor pressure of 10 kg / cm ² and a temperature of 180 ° C. for 4 hours.
Thereafter, the pressure was lowered to the atmospheric pressure, taken out of the autoclave, and dried in an oven at 105 ° C. until the attached moisture became 1% or less to obtain a final product. The results are shown in Table 6.

Examples 12 to 14 Sodium silicate (water glass No. 1) as primary curing agent
Example 9 except that 2.6% and 0.4% of sodium silicofluoride were added.
-11 was performed. The results are shown in Table 7.

[Brief description of the drawings]

FIG. 1 and FIG. 2 both show the relationship between the weight ratio of water / solid and the weight ratio of amorphous silica / (crystalline silica + amorphous silica) in the raw material for producing potassium silicate. The diagram shown.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C04B 28/18

Claims (3)

(57) [Claims] 1. A raw material mixture containing at least a siliceous raw material, a calcareous raw material, a primary curing agent, and water, wherein crystalline silica and amorphous silica are used as the siliceous raw material, and water / solid The relationship between the weight ratio of amorphous silica and the weight ratio of amorphous silica / (crystallized silica + amorphous silica) is shown by points A (1.0, 0.50), B (1.0, 0.15), C (4.0,0.5
0), D (4.0, 0.60), and E (2.0, 0.60), within the range of a pentagon, and furthermore, sodium silicate or potassium silicate as a primary curing agent, and a mixture of a siliceous raw material and a calcareous raw material. A slurry is obtained by adding 0.5 to 3.0% based on the content, and then the slurry is filled in a mold, heated and primarily cured, then demolded, and then heated and reacted under pressure. A method for producing a high-strength calcium silicate compact. 2. A raw material mixture comprising a calcareous raw material, a siliceous raw material, a primary curing agent, a fiber, a heat-resistant resin, and water, wherein the mixing ratio of the fiber and the heat-resistant resin is 2 to 10 respectively. %, And the relationship between the weight ratio of water / solid and the weight ratio of amorphous silica / (crystalline silica + amorphous silica) is determined using crystalline silica and amorphous silica as the siliceous raw material. , Points F (1.0, 0.25), G (1.0, 0.07), and H shown in FIG.
(4.0, 0.45), I (4.0, 0.55), within the range of a rectangle enclosed therein, further containing sodium silicate or potassium silicate as a primary hardening agent, relative to the content of calcareous and siliceous raw materials. A high-strength calcium silicate molding characterized by adding 0.5-3.0% to obtain a slurry, then filling it into a mold, heating and primary-curing, removing the mold, and then reacting it under pressure under heating. How to make the body. 3. A primary hardening agent wherein sodium silicate or potassium silicate is further added with 0.1 to 1.5% of sodium silicate fluoride based on the total amount of the siliceous raw material and calcareous raw material. 3. The method for producing a high-strength calcium silicate molded product according to 1 or 2.