JPH02192442A - Production of fiber-reinforced hydraulic inorganic molded article - Google Patents

Abstract

PURPOSE:To obtain a hydraulic inorganic molded article having high strength without causing the lowering of strength of organic synthetic fiber and discoloration of the molded article by stirring and mixing an organic synthetic fiber and mountain cork in water to form a composite material, mixing the material with a hydraulic inorganic substance, forming the obtained slurry in the form of a sheet or molding the slurry and curing the product in an autoclave. CONSTITUTION:The objective molded article can be produced by mixing a reinforcing fiber composed of an organic synthetic fiber and mountain cork, forming an aqueous slurry or paste from the mixture together with a hydraulic inorganic substance, forming the slurry, etc., in the form of a sheet or molding the slurry, etc., and curing the product by hydrothermal reaction in an autoclave. The reinforcing fiber is preferably polyvinyl alcohol fiber or polyacrylonitrile fiber. The amount of the mountain cork is usually about 50-10,000 pts.wt. per 100 pts.wt. of the reinforcing fiber.

Description

Detailed Description of the Invention The present invention relates to a method for producing a fiber-reinforced hydraulic inorganic molded article, and more particularly, to a method for manufacturing a fiber-reinforced hydraulic inorganic molded article, and more specifically, a method for producing a fiber-reinforced water-reinforced water body that can be cured in an autoclave using organic synthetic fibers as reinforcing fibers. The present invention relates to a method for producing a hard inorganic molded body.

For example, so-called asbestos slate boards, which use Portland cement as a hydraulic inorganic material, i.e., a binder, and asbestos as reinforcing fibers, calcium silicate boards, slag gypsum boards, etc., are typically manufactured using the Hachnik method. It is widely used as a building material because it can be mass-produced by paper-making and subsequent autoclave curing, is nonflammable, and has excellent strength. However, in recent years, the use of asbestos has been restricted because it causes so-called asbestos pollution not only in the manufacturing environment of building materials containing it but also in the usage environment.

Therefore, in recent years, the production of fiber-reinforced hydraulic inorganic molded bodies without using asbestos has been widely studied. For example, Tokuko Sho 63
No. 19465 discloses that, together with pulp and polyvinyl alcohol fiber, sepiolite, which is a type of mountain bark, is used as a freeness adjusting material to make an aqueous slurry, and this is made into paper.
A method of manufacturing an inorganic molded body by curing has been proposed.

In addition, JP-A No. 61-31337 discloses that fibrous or acicular sepiolite, attapulgite, wollastonite, etc. are used to improve the dispersibility of reinforcing fibers and for papermaking, along with mica, bulbs, reinforcing synthetic fibers, and hydraulic inorganic substances. A method has been proposed for producing a hydraulic inorganic molded body by paper forming using the slurry in order to improve its freeness.

However, in the conventional production of hydraulic inorganic molded articles using organic synthetic fibers as reinforcing fibers, including the above-mentioned method, the paper articles are cured by natural curing. Since this natural curing requires a long period of several tens of days, from an industrial standpoint, the productivity of the molded product is poor and the manufacturing cost increases.

When a paper product is cured in an autoclave, the strength of the resulting molded product is extremely low due to significant deterioration of the organic synthetic fibers, and it cannot be put to practical use at all.

For example, polyvinyl alcohol fibers are suitable as reinforcing materials because they are easily compatible with cement (and have strong strength), but when they are cured in an autoclave, the fibers deteriorate significantly and their strength is halved. Furthermore, the resulting molded body is significantly colored.

In order to solve this problem, for example, Japanese Patent Laid-Open No. 62-1
Publication No. 97342 also proposes a method of manufacturing a hydraulic inorganic molded body by autoclave curing using polyacrylonitrile fibers as reinforcing fibers, but since special polyacrylonitrile fibers are used, the manufacturing cost is high and it is not practical. I have trouble with sex.

■ is determined to do so.

As a result of intensive research to solve the above-mentioned problems in the production of conventional hydraulic inorganic molded bodies using organic synthetic fibers as reinforcing fibers, the present inventors discovered that organic synthetic fibers were stirred and mixed in advance with mountain bark in water. Then, the surface of the fibers is coated with mountain bark to form a kind of composite, which is made into a slurry for papermaking, a paste for molding, or clay with a hydraulic inorganic substance, and after papermaking or molding, it is cured in an autoclave. The inventors have discovered that by doing so, a high-strength hydraulic inorganic molded body can be obtained without reducing the strength of the organic synthetic fibers used as reinforcing fibers or discoloring the molded body, leading to the present invention.

The method for producing a fiber-reinforced hydraulic inorganic molded body according to the present invention for achieving "'" includes premixing reinforcing fibers made of organic synthetic fibers with mountain bark,
Next, this is made into an aqueous slurry or paste together with a hydraulic inorganic substance, formed into paper or molded, and then cured in an autoclave using a hydrothermal reaction.

The mountain skin used in the method of the present invention is a clay mineral having a large number of active hydroxyl groups on the surface, and refers to sepiolite, which is hydrated magnesium silicate, attapulgite, or palygorskite, which is hydrated magnesium aluminum silicate. It is called cork, mountain leather, mountain wood, etc. Meerschaum is also a type of mountain bark.

Mountain bark usually has a fibrous or powdery appearance and can be used as is, but it can be loosened beforehand.
It is preferable to use a porous fibrous form to improve compatibility with reinforcing fibers. For example, the mountain bark can be made into a porous fibrous form as described above by moistening the mountain bark and applying a high shear force thereto. In the method of the present invention, it is particularly preferable to use porous fibrous mountain bark having a fiber diameter of 10 mμ to 5 fi.

In the method of the present invention, first, reinforcing organic synthetic fibers are stirred and mixed with mountain bark in water in the presence of a surfactant if necessary. Usually, the mountain bark is first dispersed in water, and then reinforcing fibers are added thereto and stirred to disperse the fibers and mixed with the mountain bark. However, after tri-blending the mountain bark and reinforcing fibers in advance, this may be added to water and mixed by stirring.

When dispersing mountain bark in water, the content of mountain bark in water is not particularly limited, but is usually 0°05.
-50% by weight, preferably 0.1-10% by weight.

To disperse mountain bark in water, mountain bark can be simply added to water at room temperature or heated water and mixed by stirring.

However, the method of dispersing mountain bark in water is not limited at all. For example, mountain bark may be pulverized and dispersed in water using a high-speed mixer. In particular, when preparing a highly concentrated dispersion liquid, mixing using three rolls, for example, can also be employed. Alternatively, a small amount of water and mountain bark may be mixed in advance, thoroughly kneaded using a clay kneader or the like, and then mixed and stirred with water.

In this way, by dispersing the mountain bark in water, adding reinforcing fibers to it, and stirring and mixing again, the mountain bark attaches to or entangles with the surface of the reinforcing fibers, forming a type of composite or form aggregates. In this way, the clay mineral yambin adheres to the surface of the reinforcing fibers and protects them, so even if paper products or molded products containing them are cured in an autoclave, the reinforcing fibers will not deteriorate, as will be described later. First, the original physical properties including strength can be maintained substantially unchanged.

Furthermore, such a reinforcing fiber-hull composite adsorbs the hydraulic inorganic substance by stirring and mixing it with the hydraulic inorganic substance described below in water, and in particular coagulates well in the presence of a flocculant.
In this way, the paper can be easily filtered with good drainage through a wire mesh of approximately 20 mesh, and papermaking can be carried out using the conventional Hachnik method.

In the present invention, organic synthetic fibers are used as the reinforcing fibers. Specific examples include polyvinyl alcohol fibers, polyacrylonitrile fibers, polyamide fibers, polyester fibers, polyethylene fibers, polypropylene fibers, polyvinylidene chloride fibers, polyvinyl chloride fibers, polytetrafluoroethylene fibers, and the like. Among these, polyvinyl alcohol fibers or polyacrylonitrile fibers are preferably used. Such reinforcing fibers typically have a fiber summary of 0.1 to 251
(2) Fiber diameters of approximately 1 μm to 0.2 m are preferably used.

In particular, polyvinyl alcohol fibers are preferably used in the method of the present invention because they are compatible with cement (and have high strength). As mentioned above, polyvinyl alcohol fibers usually have low strength under autoclave curing conditions. It deteriorates significantly and changes color from yellow-orange to brown.

However, according to the method of the present invention, even if polyvinyl alcohol fibers are used as reinforcing fibers, as described above, the mountain bark covers the fibers and forms a composite, so even after autoclave curing, discoloration will occur. It is possible to obtain a hydraulic inorganic cured molded article that maintains reinforcing performance without deterioration or strength.

When treating reinforcing fibers with mountain bark, the mountain bark is usually
50 to 10,000 parts by weight, preferably 100 to 5,000 parts by weight are used per 100 parts by weight of reinforcing fibers. When the amount of mountain bark used is less than 50 parts by weight per 100 parts by weight of reinforcing fibers, the amount of mountain skin attached to the reinforcing fibers is too small, resulting in insufficient formation of the composite as described above. Paper products or molded products obtained using such a mixture are inferior in strength because the reinforcing fibers cannot maintain their reinforcing performance during autoclave curing as described below.

On the other hand, if the amount of lint used is more than 10,000 parts by weight per 100 parts by weight of reinforcing fibers, for example, it becomes difficult to wind up on a making roll during the papermaking process, which may impede smooth production. This is not preferable because it becomes difficult to increase the bulk specific gravity of the resulting paper product, and a high-pressure press or the like is required to obtain a product having the desired bulk specific gravity. Furthermore, the reinforcing effect of the reinforcing fibers is reduced.

Stirring and mixing of the reinforcing fibers and the mountain bark in water may be carried out in the same manner as the above-mentioned dispersion of the mountain bark in water, but if necessary, a surfactant may be used in combination. A surfactant may also be used when dispersing mountain bark in water. As the surfactant, water-soluble nonionic or anionic surfactants are preferably used.

In the method of the present invention, after preparing a composite of reinforcing fibers and mountain skin as described above, the composite is used as reinforcing fibers in the same manner as in the production of asbestos slate boards by the papermaking method. , a hydraulic inorganic substance, a flocculant, and if necessary, a valve, an inorganic filler, etc. are stirred and mixed in water to prepare an aqueous slurry for papermaking or a paste for molding.

Examples of the hydraulic inorganic substance used in the method of the present invention include various cements typified by Portland cement, silica stone, diatomaceous earth, blast furnace slag, fly ash, lime, and gypsum. For example, if Portland cement is used as the hydraulic inorganic material, a cement slate board can be obtained, and if silica, diatomaceous earth, lime, etc. whose main component is calcium silicate is used as the hydraulic inorganic material, a calcium silicate board can be obtained. By using slag, gypsum, lime, etc., slag gypsum boards can be obtained. It goes without saying that in addition to this, gypsum boards, magnesium carbonate boards, calcium carbonate boards, etc. can also be obtained by appropriately selecting a hydraulic inorganic substance.

In the present invention, as the flocculant, any of conventionally known inorganic flocculants and organic polymer flocculants can be used. Therefore, as the inorganic flocculant, for example, polyaluminum chloride, ferrous sulfate, ferric sulfate, ferric chloride, bread earth sulfate, sodium aluminate, polyaluminum sulfate, etc. can be used. When such an inorganic flocculant is used, a flocculating aid such as slaked lime, soda ash, sodium silicate, bentonite, fly ash, etc. may be used in combination.

Furthermore, as the organic polymer flocculant, both natural flocculants and synthetic flocculants can be used.

Examples of natural organic polymer flocculants include guar gum,
Mention may be made of nonionic and anionic flocculants such as sodium alginate, starch, gelatin, chitosan and the like.

As for the synthetic organic polymer flocculant, both so-called medium degree of polymerization (molecular weight in the range of several thousand to several tens of thousands) and high degree of polymerization (molecular weight in the range of several hundred thousand to 100,000) can be used. Specific examples include anionic flocculants such as sodium polyacrylate, its partial hydrolyzate, polyacrylamide partial hydrolyzate, acrylamide/sodium acrylate copolymer, polyvinylimidacillin, polyalkylaminoacrylate, Examples include cationic flocculants such as polyalkylaminomethacrylate and Mannich modified polyacrylamide, and nonionic flocculants such as polyacrylamide and polyethylene oxide. However, among these, nonionic flocculants such as polyacrylamide and polyethylene oxide with a high degree of polymerization are particularly preferred.

In the method of the present invention, when a molded body is produced by a papermaking method, the amount of such a flocculant used is usually about 3 to 30 pprO, preferably about 10 to 1100 ppr, based on the solid content in the papermaking slurry. .

In the present invention, a valve may be used in addition to the mountain skin, if necessary. The valve is useful for improving the papermaking properties of papermaking slurry. In particular, it is effective to add valves in an amount of 2% by weight or more based on the solid content of the slurry.

In the present invention, the bulb may be either a softwood bulb or a hardwood bulb, but especially when obtaining a molded article with high strength, softwood pulp is used.

Furthermore, when a papermaking method is employed and drainage properties are to be improved, for example, a beating valve or a waste paper valve is preferably used. Generally, refining valves or waste paper valves are preferably used also in order to reduce manufacturing costs.

The valve is designed to ensure the non-flammability of the resulting molded product.
Usually, in the solid content of papermaking slurry or molding paste,
It is used in a range of 5% by weight or less, but it can be used in an amount exceeding 5% by weight if necessary.

Furthermore, in the method of the present invention, an inorganic filler may be used in combination. Examples of such inorganic fillers include fibrous inorganic substances such as wollastonite, ettrin guide, sheet dry, aluminum hydroxide, and basic magnesium carbonate, flaky mica, vermiculite, pearlite,
Examples include whitebait balloons, glass fibers, slag gypsum boards, and the like. Such an inorganic filler is generally used in an amount of 1 to 20% by weight, preferably 2 to 10% by weight, based on the solid content of the slurry or paste.

In addition, in the method of the present invention, when preparing the slurry or paste, a thickening agent may be used in combination to promote the composite of reinforcing fibers and mountain skin in the slurry or paste, or to increase the plasticity of the paste. can. Such glues include starch-based glues such as carboxymethylcellulose, methylcellulose, hydroxylmethylcellulose, etc., funori, gelatin, glue, soluble keratin, tanman, konnyaku, polysaccharoids, polyvinyl alcohol, vinyl acetate emulsion, Examples include styrene-butadiene rubber latex. Especially when manufacturing calcium silicate plates,
The combined use of an emulsion binder is advantageous for improving the workability of the resulting calcium silicate plate. Thickening agents are usually found in the solid content of slurry or paste.
It is used in a range of 0.1 to 5% by weight.

In the method of the present invention, the solid content concentration in the papermaking slurry is usually in the range of 2 to 30% by weight, preferably in the range of 3 to 15% by weight.

In addition, the solid content concentration in the molding paste is usually 6
It is in the range of 0 to 90% by weight, preferably 70 to 80% by weight.
% by weight.

After preparing a papermaking slurry or a molding paste as described above, a papermaking body or a molded body is obtained according to a conventional method,
By pre-curing and then curing in an autoclave if necessary, a high-strength hydraulic inorganic cured molded article that retains the reinforcing performance of the reinforcing fibers can be obtained.

That is, conventionally, in the production of asbestos slate boards, paper forming and autoclave curing techniques are already well known. In the method of the present invention, the slurry for papermaking obtained as described above is subjected to the same papermaking method as in the production of asbestos slate to obtain a papermaking body, and this is similarly cured in an autoclave to obtain an inorganic molded body. be able to. As the papermaking method, the Hachinik method (round net papermaking method) or the Fourdrinier method can be used, but the Hachinik method is usually used.

Further, the molded body can be obtained by, for example, an extrusion method, but other methods may also be used.

Autoclave curing refers to a process in which a paper product or a molded product is heated in an autoclave with high-temperature, high-pressure saturated steam to harden the hydraulic inorganic material constituting the paper product or molded product by a hydrothermal reaction. In the present invention, the curing temperature is usually 100°C or higher, preferably in the range of 110 to 180°C, and particularly preferably in the range of 130 to 160°C, although it depends on the hydraulic inorganic substance used. In autoclave curing, the pressure is usually 1 to 10 kg/d.
, preferably in the range of 3 to 6 kg/cj. Moreover, the curing time is usually in the range of 4 to 24 hours.

In the present invention, when a paste is prepared and a molded article is obtained as described above, it is preferable to particularly use the above-mentioned thickening agent in conjunction with the paste preparation to enhance the plasticity of the paste.

As described above, according to the method of the present invention, organic synthetic fibers as reinforcing fibers are stirred and mixed in water with mountain bark in advance,
The surface of the fiber is coated with mountain bark to form a type of composite, which is made into a slurry for papermaking or a paste for molding together with a hydraulic inorganic substance, and after papermaking or molding, it is cured in an autoclave. A high-strength hydraulic inorganic molded body can be obtained without reducing the strength of the reinforcing organic synthetic fibers or discoloring the molded body.・Example The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples in any way.

In the following, the materials used are as follows.

Yamahata Need Plus PMW (manufactured by Narita Pharmaceutical Co., Ltd., powder fibrous form) Need Plus PMC (manufactured by Narita Pharmaceutical Co., Ltd., powder form) Need Plus ML100W (specially manufactured by Takeda Pharmaceutical Co., Ltd., fibrous form) Need Plus ML50D (manufactured by Shikinichi Pharmaceutical Co., Ltd.) Polyvinyl alcohol fiber AAl, 6D (manufactured by Unitika Kasei ■, fiber length 6 inches) AA
o, 3D (manufactured by Unitika Kasei ■, fiber length 3 m) Polyacrylonitrile fiber (PAN) Dolanit-10 (manufactured by Hoechst, fiber diameter 18 μm)
1 fiber length 61m) Pulp C3F60m1 (beaten pulp) Mica M-60 (manufactured by Revco) Wollastonite NYAD-G (manufactured by Nagashio Sangyo ■) Bentonite Chikuzen No. 8 (manufactured by kiln material for products ■) Silica hneem SF white powder (Japanese) (manufactured by Heavy Kagaku Kogyo ■) Cement Ordinary Portland Cement Also, below, the test method for the obtained molded body is as follows.

According to the method specified in bending strength JIS K 6911,
Measurement was performed on a board with a width of 4 cm at a span of 10 ca+.

Length change rate The method specified in JIS A 5429 was used.

Noncombustibility test In accordance with Article 108-2 of the Enforcement Order of Article 29 of the Building Standards Law, the base material test and surface test specified in Ministry of Construction Notification No. 1828 were conducted, and a pass was given an O, and a fail was given a ×.

Appearance The degree of coloring on the surface of the molded product after autoclave curing was visually observed, and no coloring was rated O1, slight coloring was rated △, and significant coloring was rated ×.

Observe the remaining state of reinforcing fibers on the fractured surface of the test piece after the fracture surface bending test. When reinforcing fibers remain, O1 indicates that some amount remains, and △ indicates that no reinforcing fibers remain. did.

Example 1 (Example of mixing mountain bark and polyvinyl alcohol fiber) Water was added to 40 g of sepiolite to make a total weight of 11 kg, and the mixture was stirred and mixed in a household mixer for about 5 minutes to obtain a paste slurry.

Separately, polyvinyl alcohol fiber AA1.6D200■
was added to 4.51 liters of water, stirred gently for about 2 seconds with a mixer to loosen the fibers, and then added 500 g of the above sepiolite slurry to make a total volume of about 51 liters, and stirred and mixed for about 5 seconds. A uniform slurry was obtained.

Thereafter, when 1 ml of a 1.5% by weight aqueous polyethylene oxide solution was added to the slurry and stirred gently, the formation of slight fibrous aggregates was observed.

Therefore, 1 m of the above polyethylene oxide aqueous solution was added.
1 was added and stirred for about 5 minutes, and the mountain bark-polyvinyl alcohol fiber composite was coagulated and precipitated.

When this composite was transferred to a Petri dish and observed, it was found that the ridges were uniformly and oriented and adhered to the surface of the polyvinyl alcohol fibers.

(Preparation of Slurry for Paper Making) Pre-beated pulp was added to a pulper so as to have a predetermined solid content for paper making, and the slurry was stirred and mixed for 5 minutes. Next, add a predetermined amount of filler to this, stir for 5 minutes,
After dispersing, polyvinyl alcohol fibers previously mixed with mountain bark were added to the slurry in the same manner as above, and 5
Stir for a minute to disperse.

A predetermined amount of Portland cement was added to the slurry thus obtained, and after stirring for 5 minutes, the slurry was transferred to Chiest to obtain a slurry with a solid content of 15% by weight. White water was added to this slurry to dilute it to a slurry solid content of approximately 8% by weight, and an anionic flocculant was added at 20 ppm based on the slurry solid content, and the slurry was transferred to a vat tank equipped with a 65-mesh cylinder and strained. . Following this, the thickness was made to 6fII using a making roll and a press, and the bulk specific gravity was 1.5.
manufactured cement boards.

Table 1 shows the formulation and also shows the paper-making rate by the above-mentioned paper-making process.

After accelerated curing of these cement plates in humid air at 60° C. for 15 hours, they were cured in an autoclave at the temperatures shown in Table 2. Table 2 shows the results of tests on the cement boards thus obtained.

For comparison, a cement board obtained in the same manner was naturally cured for 28 days at 20° C. using humid air. The results of testing the obtained cement board are shown in the third
Shown in the table.

As is clear from the above results, all of the cement boards (experiment numbers 24 to 29) manufactured using polyvinyl alcohol fibers as reinforcing fibers that were not treated with mountain bark cracked in the nonflammability test. It was a failure. Furthermore, when polyvinyl alcohol fibers were used, the reinforcing performance decreased at curing temperatures of 130°C or higher, and it appears that some of the fibers were dissolved (Experiment No. 25).
26.28 and 29).

On the other hand, when polyvinyl alcohol fibers are pretreated with a mountain bark according to the present invention, the resulting cement board retains the reinforcing performance of the fibers even after autoclave curing at a temperature of 140 to 150°C. It has also passed the nonflammability test.

In addition, in Table 3, the cement board obtained in Experiment No. 3 did not pass the nonflammability test due to a large length change rate (0,278%), weak adhesion, and insufficient solidification. It appears that it was Furthermore, it appears that the cement boards obtained in Experiments Nos. 4 and 5 did not pass the nonflammability test because the adhesion of the polyacrylonitrile fibers was weaker.

Example 2 Polyvinyl alcohol fiber (AB12 manufactured by Unitika Kasei)
00
Filled with n+1, sealed, applied to the end of a rotary mixer and mixed for about 10 minutes to obtain a flocculent powder.

Add 1 kg of cement and 3.5 g of methylcellulose (Metrose 90SH1500 manufactured by Shin-Etsu Chemical Co., Ltd.) to this powder, mix thoroughly with a rotary mixer to make a uniform powder, add 225 g of water, and add 225 g of water. The mixture was mixed twice using a screw mixer to obtain a string-like paste with plasticity.

This paste was extruded from a 15 x 15 die using a small vacuum extruder to form a prismatic molded product with a length of 12 mm.
prepared.

Among these molded products, as Comparative Example 1, 5 molded products were heated at 20°C.
It was naturally cured for 28 days to form a hardened cement body. The remaining five pieces were placed in an autoclave with a capacity of 11 filled with water at the bottom, sealed, and then autoclaved at 140°C for 12 hours to form a hardened cement body. During this autoclave curing, no discoloration of the polyvinyl alcohol fibers to brown was observed.

Table 4 shows the properties of these cured products.

As Comparative Example 2, a paste was prepared in the same manner as above except that natural wollastonite powder was used instead of mountain bark. However, this paste had rather poor plasticity, and when extruded, a slightly fluffy molded product was obtained. When this molded product was cured in an autoclave under the same conditions as above to obtain a cured product, a brown striped pattern appeared on the surface.

Moreover, as Comparative Example 3, the molded body was left to stand for 28 days and naturally cured to obtain a cured body.

Table 4 shows the properties of these cured products.

Example 3 Polyvinyl alcohol fiber (AB12 manufactured by Unitika Kasei)
00

Separately, 100 kg of cement, 2 kg of hydroxyethyl cellulose and 65 kg of polyethylene oxide powder
After mixing with a Natsuta mixer until homogeneous, while stirring and mixing with an omni mixer, gradually add the slurry containing the mixed product of the polyvinyl alcohol fiber and mountain bark, until the mixture becomes homogeneous. The mixture was stirred and mixed for about 30 minutes to obtain a sticky rice cake-like paste. This is made into a paste according to recipe A.

As a comparative example, the same polyvinyl alcohol fiber 1 as above
A slurry was obtained by stirring and mixing 24 kg of water and 24 kg of water using a Keday mixer until the mixture became uniform.

Separately, 100 kg of cement was made using a Natsuta mixer.

3 kg of Polklay (manufactured by Colloid) as a heating material, mica powder 5-80 (manufactured by Repco > 10 as a shrinkage prevention material)
kg and 3 kg of hydroxymethylcellulose were mixed for about 1 hour until homogeneous.

While stirring and mixing this with an omni mixer, gradually add the slurry containing the polyvinyl alcohol fibers to it, and stir and mix for about 30 minutes until it becomes uniform. Obtained. Prescription B
Make a paste.

Using a vacuum clay kneading machine equipped with a nozzle with an angular cross-section, pastes according to the above formulations A and B were each made into 12-length pieces.
C11 was extrusion molded into 20 irregular shaped bodies, each of which was naturally cured at a temperature of 20°C for 28 days to prepare a cured body, and the remaining 10 shaped bodies were each
It was cured in an autoclave at a temperature of 150°C for 10 hours.

A 2×4×10 cm test piece was cut out from each cured product, and its physical properties were measured. The results are shown in Table 5. Prescription A
Comparative Example 3 is a case in which a paste extrusion molded article according to Formulation B was naturally cured, and Comparative Examples 5 and 6 are cases in which paste extrusion molded articles according to Formulation B were autoclaved and naturally cured, respectively.

No change in hue was observed in the cured product using the paste of Prescription A, but a brown striped pattern appeared on the surface of the cured product using the paste of Prescription B. This striped pattern was particularly noticeable at the corners of the cured product.

Example 4 Water 900+++L Nido Plus PMW for household mixer
Add 1g of Needplus ML-100WI and stir and mix for about 5 seconds, then add polyvinyl alcohol fiber FAID (mlffl length 7m) (j-Nichika Kasei ■
) Ig was added thereto, and the mixture was further stirred and mixed for 30 seconds. Subsequently, 5 g of waste newspaper and 39.5 g of slag were added to the obtained slurry.
g, 30 g of gypsum trihydrate, 7 g of mica, 6 g of pallite, 7 g of calcium carbonate, and 2.5 g of slaked lime were added and mixed with stirring for 30 seconds.

The obtained slurry was transferred to a beaker with a capacity of 11, and 500 ppm of anionic flocculant PA-331 (manufactured by Kurita Kogyo ■) was added.
After adding 6 ml of liquid and stirring manually with a glass rod,
The mixture was transferred to a molding frame lined with a 5 cm, 50 mesh wire mesh, and filtered under suction to obtain a wet sheet.

The two wet green sheets obtained in this way were stacked together and press-bonded at a surface pressure of 40 kg/cd, then accelerated curing in humid air at 70°C for 15 hours, and then heated to the temperature shown in Table 6. After curing in an autoclave, a slag gypsum board was obtained.

As Comparative Example 7, two wet green sheets were stacked and press-bonded at a surface pressure of 40 kg/aJ, then accelerated curing in humid air at 70°C for 15 hours, and further for 28 days in humid air at 20°C. After natural curing, a slag gypsum board was obtained.

Table 6 shows the properties of the slag gypsum board thus obtained.

Furthermore, as Comparative Example 8, 900 m of water was added using a household mixer.
1 and 5 g of waste newspaper were stirred and mixed for 30 seconds, and then, along with 41.5 g of slag, the same amounts of polyvinyl alcohol fiber, trihydrate, mica, perlite, calcium carbonate, and slaked lime as above were added and stirred for 30 seconds. Mixing resulted in a slurry.

Thereafter, the obtained slurry was treated in the same manner as above, and the sixth
Autoclave curing was performed at the temperature shown in the table to obtain a slag gypsum board.

As Comparative Example 9, a slag gypsum board was obtained by accelerated curing in humid air at 70°C for 15 hours, and then natural curing in humid air at 20°C for 28 days.

Table 6 shows the properties of the slag gypsum board thus obtained.

As is clear from the above results, the slag gypsum board obtained by autoclave curing according to the present invention retains 80% or more of the bending strength of the slag gypsum board obtained by natural curing.

Example 5 Needplus PMC10g and Needplus ML50D1
Water was added to 0 g to make a total flt 1 kg, and this was stirred and mixed for about 5 seconds using a household mixer to obtain a paste-like slurry.

Separately, put 1.6D 5g of polyvinyl alcohol fiber AA in 1L of water, stir gently with a mixer for about 5 seconds to loosen the fibers, then add this to the above mountain skin slurry and stir and mix for about 5 seconds. A uniform slurry was obtained. Then, 1 ml of a 5% by weight polyethylene oxide aqueous solution was added to this slurry and stirred for about 5 seconds. A composite consisting of polyvinyl alcohol fibers and mountain skin was formed in advance.

Subsequently, 10 g of beaten pulp was added to the slurry, and about 5 g of beaten pulp was added to the slurry.
Stir and mix for seconds to obtain a homogeneous slurry.

The above slurry was charged into a pulper so that it contained 6% by weight of mountain bark, 1.5% by weight of polyvinyl alcohol fibers, and 3% by weight of pulp, and was stirred for 3 minutes. Next, 6% by weight of mica and 83.5% by weight of Portland cement were added, stirred for 5 minutes, and then paper-formed in the same manner as in Example 1 to produce a green cement board. The papermaking efficiency was 92%.

The green cement board thus obtained was initially cured and then autoclaved at 130°C. The obtained cement board had a bending strength of 273.5 kg/d and a length change rate of 0.118%, and other conditions were as described in Experiment No. (2).
) and passed the test.

Patent applicant: Takeda Pharmaceutical Company Limited Unitika Co., Ltd. Agent Patent Attorney Makino Ittobu

Claims (3)

[Claims] (1) Reinforcing fibers made of organic synthetic fibers and mountain bark are mixed in advance, then this is made into an aqueous slurry or paste with a hydraulic inorganic substance, and after papermaking or molding, autoclave curing is performed by hydrothermal reaction. A method for producing a fiber-reinforced hydraulic inorganic molded article. (2) Claim 1, characterized in that the reinforcing fibers are polyvinyl alcohol fibers or polyacrylonitrile fibers.
A method for producing a fiber-reinforced hydraulic inorganic molded article as described in 2. (3) 50 to 1000 mountain bark per 100 parts by weight of reinforcing fiber
2. The method for producing a fiber-reinforced hydraulic inorganic molded article according to claim 1, wherein 0 parts by weight are mixed.