JPH07126083A - Production of formed inorganic article - Google Patents

Abstract

PURPOSE:To provide a formed inorganic article having excellent mechanical strength and nailability, etc. CONSTITUTION:This formed inorganic article is produced by compounding 100 pts.wt. of a hydraulic formulated composition composed of calcareous powder, siliceous powder and reinforcing fiber with 0.1-10 pts.wt. of one or more additives selected from starch-based compound, polyhydric alcohol compound and organic acid salt, uniformly mixing the mixture, forming to a desired shape and curing at 120-200 deg.C in an autoclave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an inorganic molded article as a building material or a civil engineering material.

[0002]

2. Description of the Related Art Conventionally, calcium silicate boards and cement-based inorganic boards have been widely used as building materials and civil engineering materials excellent in fire resistance, heat insulation and strength, but in recent years, only room temperature curing and atmospheric curing have been possible. However, steam curing at high temperature and high pressure, that is, autoclave curing has come to be widely used as a method for producing a cement molded product having high strength and excellent durability in a short time. Large applications of these inorganic molded products include a multi-layered veneer made by a papermaking method and a lightweight plate mainly made of a building wall material by an extrusion molding method. Not only are these materials required to have a low specific gravity and are strong and tough, but they are also required to have severe performance such as nailing resistance and frost damage resistance. As these measures, asbestos was an essential component as a fluidity, shape-retaining and strength-enhancing aid for cement compacts, but asbestos fibers are toxic to the human body, so asbestos without asbestos fibers There is a strong demand for the development of a composition capable of curing an autoclave, which has excellent performance as described above. Instead of asbestos, pulp, glass fiber,
Vinylon fiber and polypropylene fiber are added as a reinforcing material, which has led to a considerable improvement in strength, but problems such as being unable to withstand high curing temperatures and often lacking mechanical properties and durability remain. There is. In addition to the reinforcing fibers, various attempts have been made to improve the strength of the cement matrix to enhance the performance of the molded product (for example, Japanese Patent Publication No. 59-30664 and Japanese Patent Laid-Open No. 64-64).
No. 56346), actually, ultrafine silica such as silica fume is required, and there are many disadvantages in terms of quantity and cost under the present circumstances.

[0003]

SUMMARY OF THE INVENTION The present invention provides a method for producing an inorganic molded article which is autoclave-cured, exhibits high strength, and has excellent properties such as bending performance and nailing performance.

[0004]

Means for Solving the Problems As a result of intensive studies made by the present inventors in order to solve the above problems, a hydraulic compound composition 100 comprising a calcareous powder, a siliceous powder and a reinforcing fiber is obtained.
0.1 to 10 parts by weight of one or two or more kinds of additives selected from the group consisting of starch compounds, polyhydric alcohol compounds and organic acid salts are added to parts by weight, and uniform mixing and shaping are performed. After that, the present invention has been completed by finding a method for producing an inorganic molded article, which is characterized by performing autoclave curing at 120 to 200 ° C.

As the calcareous powder used in the present invention, one or more kinds of ordinary Portland cement, quick lime, slaked lime, etc. are used. The siliceous powder is one that gradually exhibits hydraulic properties in the presence of lime and water, which is called pozzolan in the cement field, and has silica content such as silica stone powder, fly ash, blast furnace slag powder, silica fume, and diatomaceous earth. One or more kinds of inorganic powders having a high content of are used. As the reinforcing fiber, one or more kinds of glass fiber, carbon fiber, pulp fiber, synthetic fiber such as vinylon, polypropylene, etc. are used. In the present invention, it is preferable to use an aggregate and a fine aggregate together, and one example thereof is a hollow aggregate such as pearlite in addition to sand and crushed stone.

There is no particular limitation on the mixing ratio of the calcareous, siliceous powder, reinforcing fiber and aggregate, but calcareous 10
30 to 200 parts by weight of siliceous powder, 2 to 30 parts by weight of reinforcing fibers, and 4 to 70 parts by weight of aggregate are preferable to 0 parts by weight.

[0007] Examples of the additives added to the above hydraulic compound composition include starch compounds, polyhydric alcohol compounds and organic acid salts. Examples of the starch-based compound include raw starch such as corn starch, potato starch, wheat starch, rice starch and tapioca starch, and modified starch such as oxidized starch and phosphate esterified starch obtained from these raw starches and dextrin. Of these starch-based compounds, raw starch is preferable, and corn starch is more preferable.
These starch-based compounds may be used alone or in combination of two or more.

Examples of the polyhydric alcohol compound include glucose, sucrose, sorbitol, mannitol, pentaerythritol, glycerin and dextrin, and glucose, sucrose and sorbitol are particularly preferable, and sorbitol is particularly preferable.

Examples of the organic acid salt include gluconate, polyacrylic acid, lignin sulfonate and the like, and among these, lignin sulfonate is preferable. There is no particular limitation on the type of salt of these organic acids, sodium salt,
There are calcium salt and magnesium salt, and generally sodium salt.

The addition amount of these additives of the present invention is 0.1 to 10 parts by weight based on 100 parts by weight of the hydraulic compounding composition. If the amount is less than 0.1 parts by weight, the effect of addition cannot be obtained, and if the amount is more than 10 parts by weight, not only the expected effect is not obtained, but also a curing failure is caused, which is not preferable.

As a method for adding the above-mentioned additive to the hydraulic compounding composition, powder or liquid may be added as it is to the hydraulic compounding composition and then water may be added, or the whole amount or a total amount of the added water may be added. You may melt | dissolve and add the said additive to a part. However, when a large amount of water is used as in the papermaking method, it is necessary to adjust the concentration so that the above-mentioned addition amount is present in the final blend. Further, the above-mentioned additive or its aqueous solution may be sprayed on the molded product before curing, or the molded product before curing may be impregnated with the aqueous solution of the above-mentioned additive.

The autoclave curing in the present invention is 1
It is carried out at 20 to 200 ° C. The autoclave curing time is preferably 3 to 24 hours. In addition, prior to autoclave curing, it is preferable to perform primary curing at 5 to 80 ° C. for 12 to 30 hours, and the primary curing is more preferably steam curing under normal pressure saturated vapor pressure. Further, in the present invention, additives other than the above-mentioned additives may be used in combination as long as the effects of the present invention are not impaired. Examples thereof include fluidity improvers such as methyl cellulose and polyvinyl alcohol, boric acid compounds such as boric acid, borax, calcium borate and borate esters, water repellents such as calcium stearate,
A foam entraining agent and the like are included.

[0013]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the examples, "%" and "parts" are based on weight unless otherwise specified.

[0014]

[Evaluation method] Bulk specific gravity: Based on JIS A5413, the test piece was obtained from the weight and volume after drying at 100 ° C. for 24 hours. Bending strength and bending deflection: Measured with a span length of 5 cm in accordance with JIS A1408 "Bending test method for building boards". The maximum amount of deflection at the center of the span is the bending deflection.
The larger the bending flexure, the more flexible the molded product is, which is preferable. Nailability: It is represented by the number of nails that were not broken at the center of each of 10 samples of 3 cm square.

Example 1 5 parts of corn starch powder was added to 95 parts of a mixture consisting of 48 parts of Portland cement, 32 parts of silica stone powder and 15 parts of perlite, and 5 parts of beaten pulp was preliminarily mixed with 5 parts of water. An inorganic molded product was produced by adding the mixture to the dispersion liquid disintegrated and stirring it to form a slurry, press-molding it, and then subjecting it to primary curing at 20 ° C. for 24 hours and then autoclaving at 160 ° C. for 10 hours. . The manufacturing conditions are shown in Table 1 and the physical properties are shown in Table 2. In addition, Table 1 and Table 2 show Comparative Example 1 in the case where corn starch was not added.

Examples 2 to 4 Molded articles were produced in the same manner as in Example 1 except that the starch powder of Table 1 was used instead of the corn starch in Example 1. The manufacturing conditions are shown in Table 1 and the physical properties are shown in Table 2.

Example 5 In Example 1, polyvinyl alcohol (Kuraray P
A molded product was produced in the same manner as in Example 1 except that VA-117: degree of polymerization 1750, degree of saponification 98.5 mol%) was used in combination. The manufacturing conditions are shown in Table 1 and the physical properties are shown in Table 2.

Example 6 A molded article was produced in the same manner as in Example 1 except that boric acid was used in combination in Example 1. The manufacturing conditions are shown in Table 1 and the physical properties are shown in Table 2. In addition, Table 1 and Table 2 show Comparative Example 2 in which no corn starch was added.

Comparative Example 3 The amount of corn starch added in Example 1 was 15
A molded product was produced in the same manner as in Example 1 except that the parts were used. The results are shown in Tables 1 and 2.

[0020]

[Table 1]

[0021]

[Table 2]

Example 7 Portland cement 46 parts, silica (3500 branes) 38 parts, finely divided perlite 12 parts and beaten pulp 4
2 parts of glucose powder was mixed with 100 parts of the cement mixture consisting of 1 part, passed through a kneader, and then molded with an extruder. This molded body was subjected to primary curing for 12 hours under saturated steam at 60 ° C. under normal pressure, and then to 16 hour autoclave curing at 160 ° C. to produce a cement molded body. The manufacturing conditions are shown in Table 3 and the physical properties are shown in Table 4.

Example 8 A cement molded product was prepared in the same manner as in Example 7, except that sucrose was added instead of glucose in Example 7.
The manufacturing conditions are shown in Table 3 and the physical properties are shown in Table 4.

Examples 9 to 16 Extrusion molding was carried out in the same amount as shown in Table 3 in the same manner as in Example 7, followed by primary curing followed by autoclave curing to produce molded products. The manufacturing conditions are shown in Table 3 and the physical properties are shown in Table 4.

Comparative Example 4 When the finally mixed composition of Example 7 was cured at room temperature under high humidity instead of being cured by autoclave, the strength of the molded product after 2 weeks could hardly be measured. , Was not sufficiently cured.

Comparative Example 5 Example 1 was repeated except that glucose was not added in Example 1.
A cement molded product was produced by molding and curing in the same manner as in 1. The manufacturing conditions are shown in Table 3 and the physical properties are shown in Table 4.

[0027]

[Table 3]

[0028]

[Table 4]

[0029]

EFFECTS OF THE INVENTION According to the present invention, an inorganic molded article having excellent mechanical strength and nailability can be obtained.

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Claims (1)

[Claims] 1. One kind selected from the group consisting of starch compounds, polyhydric alcohol compounds and organic acid salts per 100 parts by weight of a hydraulic compounding composition consisting of calcareous powder, siliceous powder and reinforcing fiber, or 0.1 to 10 parts by weight of two or more kinds of additives are added, uniformly mixed and shaped, and then 1
A method for producing an inorganic molded article, which comprises performing autoclave curing at 20 to 200 ° C.