JPH06329457A - Hydraulic composition - Google Patents

Abstract

(57) [Summary] [Structure] (a) a hydraulic substance, (b) a mica powder treated with a silane compound and a polyvinyl alcohol polymer, (c) a polyvinyl alcohol polymer powder and (d) a reinforcing fiber. The hydraulic composition containing the same and the hydraulic composition at 100 ° C.
A method of producing a hydraulic molded article by carrying out autoclave curing at a temperature higher than 100 ° C. after curing at the following temperature. [Effect] When the hydraulic composition of the present invention is used, it is possible to obtain a hydraulic molded product having high strength, a small dimensional change between dry and wet, and excellent crack resistance and breakage resistance. In particular, in the case of the method of the present invention in which the hydraulic composition is first cured at a temperature of 100 ° C. or lower and then secondarily cured in an autoclave at a temperature higher than 100 ° C., water having more excellent such characteristics can be obtained. A hard molded product can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic composition containing a hydraulic material such as cement, gypsum and dreg slag, and a method for producing a hydraulic molded product from the hydraulic composition. More specifically, the present invention provides a water-based molded product which has high strength and can be effectively used in various fields such as construction, civil engineering, and ships, and which has a small dimensional change between dry and wet conditions. The present invention relates to a hardenable composition and a method for producing a hydraulically shaped product from the hardenable composition.

[0002]

2. Description of the Related Art It is widely used to mix a hydraulic material such as cement with a fiber reinforcing material to give a required strength, and to mold it into a molded product such as a thin plate and use it as a material for construction and civil engineering. Asbestos has been widely used as the reinforcing fiber in that case. However, it has been generally recognized that asbestos is harmful to the human body and its heavy use is undesirable from the viewpoint of safety and hygiene, and the handling of it has been legally regulated in Western countries.

Therefore, instead of asbestos, organic synthetic fibers such as vinylon, acrylic fiber, polypropylene fiber, polyester fiber and polyamide fiber; inorganic fibers such as glass fiber and carbon fiber; pulp and the like as a fiber reinforcing material for hydraulic materials. It is supposed to be used. However,
When these fibers are used, some reinforcing effect is obtained, but the strength corresponding to the added amount of the fibers is not expressed. Moreover, the dimensional change between dry and wet is large, and the hydraulic molded product undergoes large expansion and contraction, which causes cracks and damages, and accompanying deformation and damage of the structural material. In addition, in particular, organic fibers have the drawback of being inferior in flame retardancy.

In order to improve the above drawbacks, a method of adding mica powder to a hydraulic material (Japanese Patent Publication No. 61-29).
No. 900, Japanese Patent Publication No. 61-29901) and a method of adding polyvinyl alcohol have been proposed (Japanese Patent Publication No. 3-97644). Although the above-mentioned drawbacks are considerably improved by these methods, they are not yet sufficiently satisfactory.

[0005]

The object of the present invention is to have high strength even when fibers other than asbestos are used as a reinforcing material, and at the same time, have a small dimensional change between dry and wet conditions. It is an object of the present invention to provide a hydraulic composition and a hydraulic molded product which are excellent in crack resistance and breakage resistance.

[0006]

Means for Solving the Problems As a result of repeated studies by the present inventors for the purpose of solving the above-mentioned problems, the mica powder and the polyvinyl alcohol-based polymer, which have been subjected to a specific treatment, together with the reinforcing fiber, have a hydraulic property. When a hydraulic composition is prepared by blending it with a substance and molded and aged using the hydraulic composition, it has high strength and has little dimensional change between dry and wet, and has crack resistance and breakage resistance. It was found that a hydraulic molded product having excellent properties can be obtained. Furthermore, the present inventor has found that such excellent physical properties can be more effectively exhibited by curing the hydraulic composition under specific conditions, and completed the present invention based on these findings.

Accordingly, the present invention comprises (a) a hydraulic substance, (b) a mica powder treated with a silane compound and a polyvinyl alcohol polymer, (c) a polyvinyl alcohol polymer powder and (d) a reinforcing fiber. It is a hydraulic composition characterized by containing. Then, the present invention, after curing the above hydraulic composition at a temperature of 100 ° C. or lower, 1
A method for producing a hydraulic molded article, which comprises curing the autoclave at a temperature higher than 00 ° C.

In the present invention, as the hydraulic substance (a), any inorganic substance which reacts with water to be hardened can be used and is not particularly limited. As a preferable example of the hydraulic material,
Various types of Portland cement such as early strength or super early strength cement, blast furnace cement, alumina cement, mixed cement in which blast furnace slag, fly ash, silica, etc. are mixed, gypsum, water slag, calcium hydroxide, magnesium carbonate, silicic acid Examples include calcium. The hydraulic substance may be used alone or in combination of two or more.

In the present invention, mica powder [component (b)] treated with a silane compound and a polyvinyl alcohol polymer (hereinafter referred to as "PVA polymer") is added to the hydraulic material (a). There is no limitation on the chemical composition, crystal form, place of origin, pulverization method, etc. of the mica powder as the base of the component (b). For example, muscovite, phlogopite, biotite, soda mica, synthetic mica, etc. may be used alone or in combination. Can be used. The mica powder may have a small particle size to a large particle size and its particle size is not limited, but in terms of the reinforcing effect, the weight average particle size is 10 μm or more,
It is particularly preferable to use one having a thickness of 20 μm or more and a weight average aspect ratio of 10 or more, particularly 15 or more.

Here, the weight average particle diameter and the weight average aspect ratio of the mica powder referred to in the present invention are the values obtained as follows.

Method for measuring the weight average particle diameter of mica powder : A plurality of sieves having different openings are prepared. These sieves are used in order from the largest opening such that the sieve with the largest opening is first and the sieve with the smallest opening is last, and then the first sieve with the largest opening is used for classification. The weight of the mica powder remaining on the sieve is measured. Next, the mica powder remaining on the first sieve is classified with a second sieve having a smaller mesh than that, and the weight of the mica powder remaining on the sieve is measured. By repeating this operation in sequence, the accumulated weight of the mica powder remaining on each sieve
-Rammler diagram (a graph in which the horizontal axis represents the size of the sieve openings and the vertical axis represents the integrated weight of the residual mica powder). The weight average particle diameter of the mica powder is defined as L ₅₀ (μm) with the mesh size of the sieve through which 50% of the total weight of the mica powder passes (that is, the sieve on which the cumulative weight of the mica powder remaining on the sieve reaches 50%). L (μm) is calculated by the following formula 1.

[0012]

[Equation 1] L (μm) = 2 ^1/2 L ₅₀

Measurement of weight average aspect ratio of mica powder
Method : The weight average aspect ratio (α) of mica powder is the weight average particle diameter (L) (μm) obtained above and the weight average thickness (d) (μm) of the mica powder measured by the following method. )
From the above, the value calculated using the following mathematical formula 2 is referred to. The weight average thickness (d) at that time is a value measured by the water surface single particle film method described on page 94 of "Materials" Vol. 27 (No. 298) by Nishino and Arakawa et al.

[0014]

(2) α = L / d

The mica powder is a silane compound and P
It must be treated with a VA polymer. Examples of the silane compound in that case include γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and N-β (aminoethyl) γ-aminopropyltrimethoxysilane. , N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltris (β-methoxyethoxy)
Examples thereof include silane and vinyltriethoxysilane. These silane compounds may be used alone or in combination of two or more.

As the PVA polymer used for treating the mica powder, both unmodified ordinary PVA and modified PVA can be used. Modified P
As an example of VA, a silyl group-modified P introduced with a silyl group
Examples thereof include VA; carboxyl group-modified PVA in which an unsaturated carboxylic acid component such as itaconic acid and maleic acid is copolymerized; ion-modified PVA in which a sulfate group or a phosphoric acid group is introduced; and acetoacetyl group-modified PVA. When using modified PVA, silyl group-modified PVA and / or
Alternatively, it is preferable to use a carboxyl group-modified PVA, but it is not limited thereto, and it is preferable to use a PVA having a degree of modification with a silyl group and / or a carboxyl group in that case of 0.1 to 10 mol%. The PVA-based polymer may be used alone or in combination of two or more. The degree of polymerization and the degree of saponification of the PVA-based polymer are not particularly limited, but the degree of polymerization is 300 or more, particularly 500 to 2000, and the degree of saponification is 70 mol% or more, particularly from the viewpoint of easy treatment of the mica powder. It is preferable to use 80 mol% or more.

The treatment of the mica powder with the silane compound and the PVA-based polymer may be carried out by a method in which the silane compound and the PVA-based polymer are used together, or after the treatment with the silane compound, the treatment with the PVA-based polymer is carried out. The treatment may be carried out by treating the mica powder with a silane compound and then with a PVA-based polymer to form PV on the surface of the mica powder.
It is preferable to form the coating layer of the A-based polymer from the viewpoint of reinforcing effect on the hydraulic substance.

After treating the mica powder with a silane compound, P
When treated with a VA-based polymer, for example, a method in which a silane compound is directly used as it is or a solution in which a silane compound is dissolved in a solvent is sprayed on mica powder with stirring, a mica powder is dissolved or dispersed in a silane compound. First, a silane compound is attached to the mica powder by using a method of immersing. In that case, the adhesion amount (addition amount) of the silane compound is 0.1 to 3% by weight based on the weight of the mica powder, particularly 0.2 to
It is preferably about 2% by weight.

Next, the mica powder treated with the silane compound as described above is treated with the PVA polymer as it is, after drying or without drying. As a treatment method in that case, a method of spraying an aqueous solution of the PVA polymer on the mica powder, a method of immersing the mica powder in the aqueous solution of the PVA polymer, and the like can be adopted. The amount of the PVA-based polymer used for treating the mica powder can be variously changed depending on the kind, composition, and other conditions of the hydraulic substance to which the mica powder is added, but is not particularly limited, but generally the thickness of the surface of the mica powder is about 0. 0.005 to 2 μm, especially 0.01 to 1 μm PVA
It is preferably used in such an amount that a coating layer of the polymer is formed. If the thickness of the PVA-based polymer layer on the mica powder is too thin, the reinforcing effect of the mica powder is less likely to be exhibited, and the strength of the resulting hydraulically molded product tends to be insufficient, while if it is too thick, the silane compound and PVA-based weight Aggregation of mica powders treated by coalescence is likely to occur, and when agglomerated mica powders are mixed in a hydraulic material, the strength of the hydraulic molded product is improved and the dimensional change rate between dry and wet It will be difficult to achieve a reduction (hereinafter referred to as “dry / wet dimensional change rate”).
Even when the mica powder is treated with the silane compound and the PVA-based polymer at the same time, it is preferable to use the silane compound and the PVA-based polymer in the same proportions as described above.

Mica powder treated with a silane compound and a PVA-based polymer [hereinafter, the treated mica powder is simply referred to as "mica powder (b)"] may be added to a hydraulic substance in a wet state, or It may be dried and then added to the hydraulic material. The blending amount of the mica powder (b) in the hydraulic composition can be appropriately selected depending on the properties required for the hydraulic molded product, its application, etc., but generally, based on the total solid content weight of the hydraulic composition, 2-30% by weight in terms of dry matter, especially 2-2
The amount of 0% by weight is preferable from the viewpoint of improving the strength of the obtained hydraulic molded product and reducing the dry / wet dimensional change rate. If the amount of the mica powder (b) is less than 2% by weight, the strength cannot be improved and the dry / wet dimensional change rate cannot be sufficiently reduced.
On the other hand, if it exceeds 30% by weight, the reinforcing effect is not exhibited and it becomes difficult to obtain a high-strength hydraulic molded product.

The hydraulic composition of the present invention further contains a PVA polymer powder as the component (c). PVA
As the polymer powder (c), the same type as the above-mentioned PVA polymer used for obtaining the mica powder (b) is used. The PVA-based polymer powder (c) needs to be able to withstand the heating temperature during curing. From this point, it is preferable to use a PVA-based polymer powder having a degree of polymerization of 1400 or more, particularly 1600 or more. When the degree of polymerization is less than 1400, when the autoclave is cured at a temperature higher than 100 ° C., it will be dissolved in the water contained in the hydraulic composition and it will be difficult to exert a sufficient reinforcing effect.

The particle size of the PVA polymer powder (c) is not particularly limited, but it is preferable to use one having a small particle size,
Specifically, it is preferable to use one having a particle size of 300 μm, particularly 250 μm, which can pass through a sieve. When a PVA-based polymer powder having a large particle size which does not pass through a sieve having an opening of 300 μm is used, PVA is used during curing of the hydraulic composition.
The system polymer powder swells and its particle size becomes larger,
The resulting hydraulic molded product is likely to be deformed, the morphological stability is reduced, and the strength is reduced.

The amount of the PVA-based polymer powder (c) to be compounded may vary depending on the type of hydraulic substance and the characteristics required for the hydraulically molded product, but it is generally based on the total solid content of the hydraulic composition. 0.1 to 15% by weight, especially 0.5 to
The amount of 8% by weight is preferable from the viewpoint of the appearance, strength, and reduction of dry / wet dimensional change rate of the obtained hydraulically molded product. P
When the amount of the VA polymer powder (c) is less than 0.1% by weight, the strength is not sufficiently improved, while when it exceeds 15% by weight, the dry / wet dimensional change rate becomes large, which is not preferable.

Further, the hydraulic composition of the present invention comprises the component (d)
As a reinforcing fiber. 1 as the reinforcing fiber (d)
Those capable of withstanding autoclave curing performed at a temperature higher than 00 ° C. are preferable, and fibers that withstand such conditions include pulp, carbon fiber, aramid fiber, polyarylate fiber, metal fiber, polyvinyl alcohol fiber, acrylic fiber, A polypropylene fiber etc. can be mentioned. Among them, pulp, carbon fiber, aramid fiber, polyarylate fiber and metal fiber are particularly preferably used. The reinforcing fibers may be used alone or in combination of two or more.

The amount of the reinforcing fiber (d) blended is such that the flexibility (handlability) of the hydraulic composition before curing, the flame retardancy of the resulting hydraulic molded product, the dry / wet dimensional change rate, etc. It is preferably from 0.3 to 15% by weight, particularly from 1 to 8% by weight, based on the total solids weight of the hydraulic composition. If the content of the reinforcing fiber (d) is less than 0.3% by weight, the strength will not be sufficiently improved, while if it exceeds 15% by weight, the appearance of the hydraulically molded product will be poor and the dry / wet dimensional change rate will be poor. Undesirably increases.

The hydraulic composition of the present invention comprises, in addition to the above-mentioned components, one of the other components usually used in hydraulic compositions.
If necessary, it may contain one species or two or more species,
Examples of such other components include glass balloons, shirasu balloons, fly ash, sand, gravel, perlite, inorganic fillers such as polystyrene beads and lightweight aggregates,
Examples thereof include thickeners such as boric acid and borax. When compounding such an inorganic filler or a lightweight aggregate in a hydraulic composition, the compounding amount thereof can be appropriately selected according to the type of the hydraulic material and the application of the hydraulic substance,
Generally 0.5 based on the total solids weight of the hydraulic composition.
It is preferably blended in a proportion of ˜50% by weight, particularly 2 to 30% by weight. Thickeners such as boric acid and borax are P
It is preferably blended in a proportion of 0.5 to 5% by weight based on the weight of the VA polymer powder (c).

Then, the above-mentioned hydraulic material (a), mica powder (b), PVA polymer powder (c) and reinforcing fiber (d) and, if necessary, other components as described above together with water. A hydraulic composition containing water is prepared by mixing. The solid content concentration at that time is not particularly limited, but is generally 0.5 to 50% by weight, and particularly preferably 2 to 30% by weight.
In mixing the above components and water, the mixing method and mixing means are not particularly limited and conventionally known methods can be adopted, for example, a concrete mixer, a screw type kneading device, a peller type kneading device, or the like. can do.

Next, the water-containing hydraulic composition prepared as described above is molded. The molding method is not particularly limited, and any method that has been conventionally used in the production of a hydraulic molded product can be adopted, and for example, a mold molding method, an extrusion molding method, a papermaking molding method, a flow-on method, a dry method, etc. Can be mentioned.

A final hydraulic molded product is manufactured by curing the molded product obtained above. The curing method at that time is not particularly limited, and any known curing method of the hydraulic molded article can be adopted, and examples thereof include autoclave curing, steam curing, natural curing, and combinations thereof. Among them, especially, if the method of performing primary curing at a temperature of 100 ° C. or lower for a certain degree (usually about 5 to 50 hours) and then performing secondary curing by an autoclave at a temperature higher than 100 ° C., the strength is further improved. It is desirable because a hydraulic molded product having a large size and a reduced dry / wet dimensional change rate can be obtained.

The hydraulic composition of the present invention and the hydraulic molded product obtained from the hydraulic composition can be widely used in various fields such as construction, civil engineering, and ships. In particular, they have high strength and small dry / wet dimensional change. Depending on the rate, roof, outer wall, inner wall, flooring,
It can be used very effectively as a building material for gates, road blocks, revetment blocks, etc.

[0031]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In the following examples, the bending strength and the rate of change in water absorption length (dimensional stability) of the molded product were determined as follows.

Bending strength : JIS with span of 50 mm
It measured based on K7203. Water absorption length change rate (dimensional stability) : Based on JIS A5418, dried at 60 ° C for one day
The length at the time of immersion in water at 0 ° C. for one day was measured to obtain the change rate.

Examples 1 and 2 (1) In a super mixer (for 20 liters; manufactured by Kawata Manufacturing Co., Ltd.), mica powder [Kuraray Co., Ltd. "Clarite Mica 60-C";muscovite; weight average particles Diameter 340 μm, weight average aspect ratio 80],
Silane-treated mica powder was prepared by adding 5% by weight of γ-aminopropyltriethoxysilane [“SANLAACE S330” manufactured by Chisso Corporation). (2) Silane-treated mica powder 10 prepared in (1) above
10 parts by weight of 0 parts by weight of a carboxyl group-modified PVA [“POVAL KM-118” manufactured by Kuraray Co., Ltd .; degree of polymerization 1800]
A 35% by weight aqueous solution of 35% by weight was mixed and dried with an evaporator while stirring to obtain a mica powder successively treated with a silane compound and PVA (a thickness of a carboxyl group-modified PVA coating layer was about 0.2 μm).

(3) Mica powder obtained in (2) above, unmodified PVA-based polymer powder passed through a sieve having an opening of 250 μm [“POVAL 117” manufactured by Kuraray Co., Ltd .; degree of polymerization 175
0], beaten pulp, Portland cement (manufactured by Onoda Cement Co., Ltd.) and boric acid in the proportions shown in Table 1 below, and 60 parts of this mixture (solid content) with respect to 1 liter of water.
A dispersion liquid was prepared by dispersing at a rate of g, and the papermaking operation was repeated 5 times using a tappy papermaking machine to obtain a laminate having 5 layers. This laminate was press-molded at a pressure of 75 kg / cm ² to prepare a molded plate. (4) The molded plate obtained in (3) above is heated at a temperature of 50 ° C.
After primary curing for 24 hours under the condition of humidity of 100%, autoclave curing was performed for 24 hours under the condition of temperature 170 ° C. and humidity of 100% to produce a cured molded article. (5) A test piece was cut out from the cured molded article obtained in (4) above, and its bending strength and water absorption length change rate were measured by the methods described above, and the results shown in Table 1 were obtained.

Example 3 γ-methacryloxypropyltriethoxysilane as a silane compound used in the treatment of mica powder [“SANLAACE S71” manufactured by Chisso Corporation]
0 "] in the proportions shown in Table 1, and as a PVA-based polymer, silyl group-modified PVA [" Poval KM "manufactured by Kuraray Co., Ltd.
-117 "; degree of polymerization 1750] in the ratio of Table 1,
The amount of the mica powder treated with silane and PVA,
A cured molded article was produced in the same manner as in Example 1 except that the amounts of PVA-based polymer powder and beaten pulp were changed as shown in Table 1. A test piece was cut out from the obtained cured molded article, and its bending strength and water absorption length change rate were measured. The results are shown in Table 1.

Example 4 The amounts of the silane compound and PVA used for the treatment of the mica powder are set as shown in Table 1, and the blended amount of the treated mica powder is changed as shown in Table 1 to obtain a silyl group as the PVA powder. A modified molded product was prepared in the same manner as in Example 3 except that the modified PVA [“Poval KM-117” manufactured by Kuraray Co., Ltd.] was used in the ratio shown in Table 1 and the beating pulp content was changed as shown in Table 1. Manufactured. A test piece was cut out from the obtained cured molded article, and its bending strength and water absorption length change rate were measured. The results are shown in Table 1.

Example 5 As the mica powder, "Clarite Mica 400-W" (white mica; weight average particle diameter 18 μm; weight average aspect ratio 35) manufactured by Kuraray Co., Ltd. was used.
This was treated with γ-glycidoxypropyltrimethoxysilane in an amount shown in Table 1 and a silyl group-modified PVA [“Poval KM-117” manufactured by Kuraray Co., Ltd.] and blended at a ratio of Table 1 to obtain a PVA powder. Silyl group modified PVA as
A cured molded article was produced in the same manner as in Example 1 except that "POVAL KM-117" manufactured by Kuraray Co., Ltd. was used in the ratio shown in Table 1 and borax was used instead of boric acid. A test piece was cut out from the obtained cured molded article, and its bending strength and water absorption length change rate were measured. The results are shown in Table 1.

Example 6 As the mica powder, phlogopite [“Szolite Mica 40-S” manufactured by Kuraray Co., Ltd .; weight average particle diameter 650 μm; weight average aspect ratio 90] was used, and the amount was shown in Table 1. Of γ-glycidoxypropyltrimethoxysilane and silyl group-modified PVA [“POVAL KM-117” manufactured by Kuraray Co., Ltd.] were blended in the proportions shown in Table 1 to obtain unmodified PVA as PVA powder.
A cured molded article was produced in the same manner as in Example 1 except that "POVAL 117" manufactured by Kuraray Co., Ltd. was used in the ratio shown in Table 1 and borax was used instead of boric acid. A test piece was cut out from the obtained cured molded article, and its bending strength and water absorption length change rate were measured. The results are shown in Table 1.

Comparative Example 1 Portland cement, untreated mica powder [Clarite Mica 60 manufactured by Kuraray Co., Ltd.
-C "] and boric acid were mixed in the proportions shown in Table 1, and a cured molded article was produced in the same manner as in Example 1. A test piece was cut out from the obtained cured molded article, and its bending strength and water absorption length change rate were measured. The results are shown in Table 1.

Comparative Example 2 Portland cement, unmodified PVA powder, beaten pulp and boric acid were mixed in the proportions shown in Table 1, and a cured molded article was produced in the same manner as in Example 1. A test piece was cut out from the obtained cured molded body, and its bending strength and water absorption length change rate were measured.
It was as shown in.

Comparative Example 3 Portland cement, silane obtained in (2) of Example 1 and mica powder treated with PVA, beaten pulp and boric acid were mixed in the proportions shown in Table 1, and the same as in Example 1. Then, a cured molded article was produced. A test piece was cut out from the obtained cured molded article, and its bending strength and water absorption length change rate were measured. The results are shown in Table 1.

Comparative Example 4 Portland cement, mica powder treated with silane obtained in (2) of Example 1 and PVA, 10% by weight aqueous solution of unmodified PVA [“Poval 117” manufactured by Kuraray Co., Ltd.] The beaten pulp and boric acid were mixed in the proportions shown in Table 1, and a cured molded product was produced in the same manner as in Example 1. A test piece was cut out from the obtained cured molded article, and its bending strength and water absorption length change rate were measured. The results are shown in Table 1.

[0043]

[Table 1]

From the results shown in Table 1 above, it can be seen that the cured molded articles obtained in Examples 1 to 6 have a large bending strength and a small water absorption length change rate, and are excellent in both physical properties. On the other hand, although the cured molded articles obtained in Comparative Examples 1, 3 and 4 have a small water absorption length change rate, their flexural strength is significantly inferior to the cured molded articles of Examples 1 to 6. It can be seen that the cured moldings obtained in Comparative Example 2 are significantly inferior to the cured moldings of Examples 1 to 6 in both flexural strength and water absorption length change rate.

[0045]

The present invention containing (a) a hydraulic substance, (b) a mica powder treated with a silane compound and a polyvinyl alcohol polymer, (c) a polyvinyl alcohol polymer powder and (d) a reinforcing fiber. By using the hydraulic composition (1), it is possible to obtain a hydraulic molded product having high strength, a small dimensional change between dry and wet conditions, and excellent crack resistance and breakage resistance. Then, the above hydraulic composition 1
When a hydraulic molded product is produced by the method of the present invention in which the autoclave is cured at a temperature higher than 100 ° C. after being cured at a temperature of 00 ° C. or less, a hydraulic molded product further excellent in the above-mentioned properties can be obtained.

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Claims (2)

[Claims] 1. A composition comprising (a) a hydraulic substance, (b) a mica powder treated with a silane compound and a polyvinyl alcohol polymer, (c) a polyvinyl alcohol polymer powder, and (d) a reinforcing fiber. A characteristic hydraulic composition. 2. A method for producing a hydraulic molded article, which comprises curing the hydraulic composition of claim 1 at a temperature of 100 ° C. or lower and then curing it in an autoclave at a temperature higher than 100 ° C.