JPH06341093A - Water-dispersible fibrous sheet, reinforcing fiber material for hydraulic inorganic material and production of fiber-reinforced hardened body using the same - Google Patents

Abstract

PURPOSE:To obtain a water-dispersible fibrous sheet or a reinforcing fiber material for a hydraulic inorganic material, composed of a material formed into a sheet containing reinforcing fiber, pulp fiber, a water-soluble binder and further a specific fiber dispersing agent in a specified proportion, readily and homogeneously dispersible and capable of manifesting excellent affinity for a matrix material. CONSTITUTION:The water-dispersible fibrous sheet or a reinforcing fibrous material for a hydraulic inorganic material is obtained by mixing and dispersing (A) 20-93wt.% reinforcing fiber, especially carbon fiber with (B) 5-80wt.% pulp fiber, preferably papermaking pulp fiber and (C) 2-25wt.% water-soluble binder, e.g. starch, PVA or CMC and further, as necessary, (D) a fiber dispersing agent having 5-25 HLB and forming a sheet of paper. Since the resultant supply material for reinforcing fiber is readily disintegrated in water, uniformly dispersed and firmly bonded to a matrix material, it is extremely suitable. Furthermore, this material is suitable as the supply material for functional fiber such as an electrically conductive material or a filter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of defibrating in a short time when placed in water and uniformly dispersing the constituent fibers thereof in water. Suitable for use as a packaging material when various chemicals are added to a water-based material, and as a supplementary material for fibers when a state in which fibers are homogeneously dispersed is required, such as a conductive material and a filter. , A novel water-dispersible fiber sheet, a reinforcing fiber material for a hydraulic inorganic material, and a method for producing a fiber-reinforced cured body using the same.

[0002]

2. Description of the Related Art Inorganic fibers such as glass fibers, carbon fibers, metal fibers, ceramic fibers, and various whiskers are blended with a matrix material such as plastics, rubber or metal cement as a reinforcing material for reinforcement or performance improvement. There is. Further, organic fibers such as pulp fibers, hemp, kapok fibers, and woody plant fibers are used as components of composite materials with plastic resins.

These are usually molded by stirring or kneading with the raw materials constituting the matrix. However, as a common problem when using these fibers, (1) it is difficult to evenly disperse the fibers in the matrix material, especially when mixed in a hydraulic inorganic material, and to obtain a more uniform dispersion. When strong agitation is performed, there are disadvantages such as cutting of fibers and formation of fiber lumps called fiber balls, and (2) weak adhesion between the fibers and the matrix. Sufficient reinforcement effect cannot be obtained.

In order to solve such a problem, for example, a method of attaching a surfactant to the fiber surface (Japanese Patent Laid-Open No. 4-2 / 1992).
1556), a method of blending a non-rounded inorganic filler (JP-A-58-181761), a method of treating a fiber with a silane coupling agent, and then attaching an activator (JP-A-3-81). 150241), a method of blending fibrillated fibers (JP-A-52-49235).
Japanese Patent Laid-Open Publication No. 4-65338), a method using pre-focused fibers, and the like have been proposed.
These methods have problems that the above two problems cannot be solved at the same time, and that they are economically difficult to put into practical use.

On the other hand, in order to save the trouble of weighing each component at the time of compounding and to facilitate the dispersion of each component, a compounding material containing all the components to be added is prepared in advance and is prepared in a matrix. There is also a method of batch injection into.

For example, a mixture of carbon fiber, an aggregate and a binder in a predetermined ratio is dried, and a compounding material for cement mortar (Japanese Patent Laid-Open No. 62-3055), carbon fiber and a water-soluble polymer binder are mixed. Is molded into a felt shape,
There is known a method of producing a carbon fiber reinforced cement by cutting a necessary amount and adding it to cement mortar (Japanese Patent Laid-Open No. 1-308858).

[0007] Separately, a composite sheet is also prepared by mixing inorganic or organic fibers with other materials and forming into a composite sheet. For example, among metal short fibers, inorganic short fibers and organic short fibers, A composite paper prepared by making a mixture of at least two kinds of fibers selected from the above and microfibrillated cellulosic fibers, which is useful as a base material that imparts reinforcing properties, electrical insulating properties, thermal conductivity and heat resistance to plastics (Patent Document 1) 60-8
8199), a sheet for reinforcing plastics, ceramics, and metal made from inorganic fibers and fibrillated organic fibers (JP 62-191595 A), diameter 0.01 to 4 μm, aspect ratio 2 to 100. 1,000
Carbonaceous fiber-containing paper containing carbonaceous fiber and pulp (JP-A-63-288298), a filter comprising a sheet containing fine fibrous cellulose and activated carbon fiber (JP-A-3-167390) , A wrapping paper, which integrates an alkali-soluble polymer into a sheet containing a papermaking fiber and a water-insoluble carboxymethylcellulose and can be easily disintegrated when used (JP-A-4-174792), etc. There is.

However, none of these compounding materials is suitable as a fiber supply source, and when they are put into water, they are easily defibrated, uniformly dispersed and intimately mixed with the matrix. No water dispersible fiber material is known to be a good fiber source.

[0009]

DISCLOSURE OF THE INVENTION The present invention can be easily dispersed in water and can be easily dispersed in water when used as a reinforcing fiber source for matrix materials such as plastics, ceramics and cement. The purpose of the present invention is to provide a water-dispersible fiber material that exhibits good affinity.

[0010]

Means for Solving the Problems The inventors of the present invention can easily disintegrate and uniformly disperse when put in an aqueous medium, and mix this with a matrix material to form a solid matrix. Give a bonded homogeneous fiber-containing molding,
As a result of repeated intensive research to develop a water-dispersible fiber material, a reinforcing fiber, a pulp fiber, a water-soluble binder and by using a paper product obtained by paper-making a mixture of a fiber dispersion material optionally used, It has been found that the object can be achieved, and the present invention has been completed based on this finding.

That is, the present invention provides (A) a reinforcing fiber,
The present invention provides a water-dispersible fiber sheet comprising a paper product of (B) pulp fiber and (C) water-soluble binder, or a water-dispersible fiber sheet containing (D) a fiber dispersant.

The reinforcing fiber used as the component (A) in the present invention is not particularly limited, and it can be selected from among those conventionally used for reinforcing matrix materials such as plastics, ceramics and concrete. It may be appropriately selected, and preferably any of conventionally known reinforcing short fibers may be used. Examples of such reinforcing fibers include polyethylene, polypropylene, polyvinyl alcohol fibers, polyvinyl acetate, polyamide, polyethylene terephthalate, polycarbonate, polyvinyl chloride, organic fibers such as polyvinyl fluoride, glass, carbon, asbestos, boron, and the like.
Examples thereof include ceramic fibers such as alumina and silicon carbide, and inorganic fibers such as metal such as steel, stainless steel and aluminum. Among these, carbon fibers are particularly preferable. These may be used alone or in combination of two or more.

When a short fiber is used as the reinforcing fiber of the component (A), the fiber length is usually 1 to 50 mm and the diameter is 2 to 25.
μm, preferably fiber length 3 to 30 mm, diameter 5 to 20 μm
Those of m are preferred. If the fiber length is less than 1 mm, the loss increases due to passing through the mesh such as a wire mesh during the papermaking process.
If it exceeds, dispersibility tends to deteriorate when dispersed in water. Further, if the fiber diameter is less than 2 μm, the loss increases by passing through the mesh of the wire mesh etc. at the time of paper making, and if it exceeds 25 μm, the peelability from the net of the wire mesh etc. tends to deteriorate at the time of paper making.

The pulp fiber used as the component (B) is not particularly limited, and for example, softwood materials such as pine, cedar, cypress, fir, and hemlock used as raw materials for papermaking, and beech, birch, oak, and sen. Non-wood pulp made from hardwood, such as mechanical pulp, chemiground pulp, semi-chemical pulp, chemical pulp and hemp, Mitsumata, Kozo, Gampi, etc., as well as waste paper pulp for re-papermaking, synthetic pulp Etc. are used, and among them, pulp fibers for papermaking are preferable. These may be used alone,
You may use it in combination of 2 or more type.

The component (B) is difficult to separate from the matrix by promoting defibration in water and by being entangled with the reinforcing fibers in the matrix, and by utilizing hydrophilicity, the adhesiveness between the matrix and the reinforcing fibers. Used to improve the

Examples of the water-soluble binder as the component (C) include starch, polyvinyl alcohol, polyethylene glycol and carboxymethyl cellulose, and various shapes are used, and among them, fibrous shape is preferable. Furthermore, depending on the application, acid-type carboxymethyl cellulose that does not dissolve in ordinary water, but dissolves only in alkaline water (degree of carboxyl group substitution: DS
= 0.2 to 1.5) and the like, and an alkaline water-soluble binder can also be used. One of these may be used, or 2
You may use it in combination of 2 or more types.

The water-dispersible fiber sheet of the present invention also comprises
Further, a fiber dispersant (D) may be contained in order to further improve the defibration and dispersion of each fiber. As the fiber dispersant of the component (D), for example, a nonionic, anionic, or cationic surfactant that makes the surface hydrophilic by adsorbing it on the fiber surface, penetrates between fibers, and has a ball bearing effect. Examples thereof include fine particles of silica fume, talc, silica sand, etc., in which fibers are dispersed by, and among these, a surfactant having an HLB (by Kawakami's calculation method) of 5 to 25, preferably 8 to 20 is suitable. In particular, nonionic surfactants, especially the general formula (I) R ^1- [OA] _n -OR ² (I) [wherein R ¹ is R ³ -CO-, R ³ -CO-N-, R ³ , R
³ -NH- or R ³ -S- (wherein, R ³ is an aliphatic hydrocarbon group of C ₁₀ -C ₂₈₎ a, R ² is a hydrogen atom or a lower alkyl group, A is a C ₂ -C ₄ An alkylene group which is one or more types and n is an integer of 5 to 50] is preferable.

When the HLB value of the surfactant is 5 or less, it becomes difficult to make the surface of the fiber hydrophilic, and when it exceeds 25, the adsorptivity to the fiber decreases. In the nonionic surfactant represented by the general formula (1), the aliphatic hydrocarbon group having 10 to 28 carbon atoms represented by R ³ may be a saturated or unsaturated one having a straight chain or a branched chain. The thing of 14-24 is preferable. Less than 10 carbon atoms, or 28
If larger, it is difficult to make the fiber surface hydrophilic and the dispersibility is poor. It is desirable that n is in the range of 10 to 30, and if it is less than 5, it is difficult to make the surface of the fiber hydrophilic, and
If it exceeds, it is not sufficiently adsorbed on the fiber surface. Also, C _{2 of} A
If alkylene group -C ₄ is 2 or more, for example it is by block addition, be by random addition performance does not change.

Specific examples of the nonionic surfactant represented by the general formula (1) include (i) alcohol type: stearyl alcohol, oleyl alcohol, cetyl alcohol, and alcohols synthesized by the oxo method, the Ziegler method and the like. Alkylene oxide adduct (ii) Fatty acid type: alkylene oxide adduct of natural and synthetic fatty acids such as palmitic acid, myristic acid, behenic acid, lignoceric acid and tallow fatty acid (iii) Fatty acid ester type: oleic acid methyl ester, lignoceric acid ethyl ester Alkylene oxide adducts such as esters and methyl esters of soybean oil fatty acids (iv) Amine: alkylene oxide adducts such as cetylamine, stearylamine, myristylamine (v) Amides: hardened tallow fatty acid amide, oleoamide, arachidami And the like and alkylene oxide adducts and the like. These fiber dispersants may be used alone or in combination of two or more. The fiber dispersant may be added when the components (A) to (C) are made into a paper product, or may be added to the paper product and attached thereto.
It is usually added during papermaking.

The content of each component in the fiber material of the present invention is (A) based on the total weight of the components (A), (B), (C) and optionally (D). In the case of the ternary system of (B) and (C),
Component (A) is 20 to 93% by weight, preferably 50 to 90
% By weight, 5 to 80% by weight of component (B), preferably 7 to
It is desirable that the content of 30% by weight and the component (C) be in the range of 2 to 25% by weight, preferably 3 to 20% by weight, and in the case of a four-component system in which the component (D) is further added to these three components. , (A) component is 20 to 93% by weight, preferably 50 to 93% by weight.
90% by weight, the component (B) is 4.99 to 80% by weight, preferably 7 to 30% by weight, and the component (C) is 1.99 to 25%.
%, Preferably 3 to 20% by weight, and the component (D) is 0.1.
It is desirable to be in the range of 01 to 10% by weight, preferably 0.05 to 5% by weight. In any case, if the content of the component (A) is too small, the effect as a reinforcing material is small, and if it is too large, it is difficult to obtain a paper product, especially a sheet-shaped product.
Further, if the content of the component (B) is too small, the entanglement of the fibers is small, and it is difficult to obtain a paper product, especially a sheet-like product,
If the amount is too large, the water dispersibility of the obtained paper product, especially the sheet-like product, will deteriorate. Further, if the content of the component (C) is too small, a sufficient binding force cannot be obtained, and if it is too large, the water dispersibility of the obtained paper product, particularly the sheet-like product, decreases. In the four-component system, if the content of the component (D) is less than 0.01% by weight, the dispersibility of the fiber is not sufficient, and if it exceeds 10% by weight, the dispersion effect commensurate with the amount used cannot be obtained. It is economically disadvantageous.

The basis weight of the water-dispersible fiber sheet of the present invention is usually 10 to 250 g / m ² , preferably 20 to 200 g / m ² .
m ² , more preferably selected in the range of 40 to 180 g / m ² . If this amount exceeds 250 g / m ² , the water dispersibility tends to decrease, while if it is less than 10 g / m ² , a large size water-dispersible fiber sheet is required to be added in order to obtain the desired strength, and work efficiency is increased. Is reduced.

Such a paper product can be produced, for example, as follows. That is, first, the carbon fiber of the component (A) is defibrated and dispersed in an aqueous medium, preferably in combination with a fiber dispersant of the component (D). If desired, a thickener such as a water-soluble polymer may be added to the fiber dispersion thus prepared to adjust the viscosity, or as a filler when it is finally formed into a sheet. Inorganic powder such as talc can also be added. on the other hand,
The pulp fiber as the component (B) is beaten, if necessary, and then added into the above-mentioned fiber dispersion together with the water-soluble binder as the component (C), and stirred until it becomes sufficiently homogeneous. Next, this product is made by a hand-made method such as a distillation method or a flow-through method, or a mechanical making method using a Fourdrinier paper machine, a round-net paper machine, a short-net paper machine, and the like, and then dried. The desired paper product is obtained.

The paper product thus obtained is particularly preferably used as a reinforcing fiber material for hydraulic inorganic materials. A fiber-reinforced cured product can be produced by kneading and hardening this reinforcing fiber material for a hydraulic inorganic material with at least a hydraulic inorganic material and water. The water-dispersible fiber material of the present invention can be used alone to produce a good fiber-reinforced cured product, but is used in combination with conventionally used dispersion aids such as silica fume and thickeners. It is also possible.

As the hydraulic inorganic material, various inorganic hydraulic materials used in the fields of construction and civil engineering are used. Examples of such a hydraulic material include Portland cement, blast furnace cement, alumina cement and calcium silicate. , Gypsum, calcium aluminate, hydraulic lime, and the like, and these may be used alone or in combination of two or more.

In the method for producing a hardened product of the present invention, it is particularly preferable to use a cement mixture such as fresh concrete or fresh mortar. The cement mixture contains cement, aggregate, water, and various admixtures (agents) as necessary. The aggregate is not particularly limited, but for example, sand such as silica sand, gravel, crushed stone, silica-based powder, shirasu, shirasu balloon, perlite, pumice stone, diatomaceous earth, slag, coal ash, kaolin, bentonite, glass pieces, etc. Used. Further, as the admixture (agent), a fluidizing agent, an AE agent,
Examples thereof include AE water reducing agent, high performance AE water reducing agent, curing accelerator, setting retarder, separation reducing agent, rust preventive agent, swelling agent, polymer admixture, shrinkage reducing agent, coloring agent and reinforcing material.

The content ratio of each component of the cement mixture may be a ratio which is usually used.
Aggregate not exceeding 500% by weight, preferably 300% by weight, 20-100% by weight, preferably 30-7
0% by weight of water is used.

The mixing ratio of the reinforcing fiber material for the hydraulic inorganic material in the production of the fiber reinforced cured product varies depending on the kind of the hydraulic inorganic material, the ratio of the hydraulic inorganic material to water, the purpose of use, etc. 1 to the total amount of kneaded material containing
-15 wt%, preferably 1-5 wt% is selected. If this ratio is too small, the desired effect will not be fully exerted, and if it is too large, the dispersion of the fibers will become difficult and the reinforcing effect will tend to peak. In particular, when blended in a cement mixture, this proportion is selected in the range of 1 to 7% by weight, preferably 1 to 5% by weight, based on the total amount of the kneaded product.

[0028]

The water-dispersible fiber sheet of the present invention can be decomposed in water in a short time to uniformly disperse the fiber component in water. Like materials and filters,
It is preferably used as a supplementary material for functional fibers when a state in which fibers are uniformly dispersed is required. At that time, the pulp fibers are entangled with the reinforcing fibers, making it difficult to separate the fibers from the matrix, and due to the hydrophilicity of the pulp fibers,
Improves the adhesion between fibers and matrix.

Further, when the water dispersible fiber sheet contains a fiber dispersant, the fiber component can be homogeneously dispersed in a short time by its action. In particular, when this water-dispersible fiber sheet is used as a reinforcing fiber material for a hydraulic inorganic material by blending it with an aqueous mixed system containing a hydraulic inorganic material, defibration in a short time,
It can be decomposed and the fiber component can be homogeneously dispersed in the aqueous mixing system. Also, when a surfactant is used as the fiber dispersant, the surfactant remains attached to the fiber surface even after drying, and the fiber surface is hydrophilized, so that it penetrates between the fibers of the matrix. Is promoted, and the adhesive force is further improved. Further, according to the method of the present invention, the reinforcing fiber material can be blended with good working efficiency, and further, the fibers can be defibrated and decomposed in a short time at the time of kneading, and the fiber components can be uniformly dispersed, so that the fibers are uniformly dispersed. The fiber-reinforced cured product can be produced easily and efficiently.

[0030]

The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto. Examples 1 to 10 and Comparative Examples 1 to 4 The components shown in Table 1 were mixed and dispersed in water, and paper-making was performed with a square sheet machine for TAPPI test. The compositions of Comparative Examples 1 and 4 could not be made into paper. Where component (A)
The properties of the fibers used as are shown in Table 2.

The basis weight 80 g / m ² thus obtained
The performance of the sheet-shaped papermaking product of was evaluated by the following method. The results are shown in Table 3. <Dry Tensile Strength> The obtained paper product was cut into a strip having a width of 25 mm and a length of 250 mm, and using Tensilon (manufactured by Toyo Baldwin Co., Ltd .: RPM-100), a pulling speed of 200 mm / min and a test piece gripping interval. The strength at break was measured under the condition of 200 mm.

<Water Dispersibility> Examples 1 to 9 and Comparative Examples 2 to 2
For the papermaking product of No. 3, this was cut into 20 × 20 mm, and 100 ml of water in a 200 ml beaker was poured into a stirring liquid stirred at 1700 rpm with a stirrer until the sheet prototype could not be stopped. The time was measured. Further, the paper product of Example 10 was tested in the same manner as in Example 1 except that an aqueous NaOH solution (pH 13.0) was used instead of water.

[0033]

[Table 1]

* 1 CF: carbon fiber, GF: glass fiber, VF: vinylon fiber * 2 NBKP: softwood bleached sulfate pulp, LBKP: hardwood bleached sulfate pulp * 3 PVA: fibrous polyvinyl alcohol (Nichibi Co., saponification 96 mol%, molecular weight 1150), CMC-
H: Fibrous acid type carboxymethyl cellulose (Nichirin Chemical Co., Ltd., CDS = 0.4), CMC-Na: Fibrous carboxymethyl cellulose (Nichirin Chemical Co., Ltd.)

[0035]

[Table 2]

[0036]

[Table 3]

From the above, it can be seen that while the paper products of the respective examples are water-dispersible fiber sheets which disperse in water in a short time, the paper products of the comparative examples take some time to disperse in water. I understand.

Further, the obtained paper product was used as a reinforcing fiber material, and each component was stirred at the following mixing ratio for 2 minutes to prepare a mortar. Ordinary Portland cement: 2000 g Water: 800 g River sand (produced by Kimitsu): 1000 g Reinforcing fiber material: 60 g Admixture (water reducing agent): 0.3% by weight (against cement)

This mortar is 4 cm × 4 cm × 16 cm
Was filled in the mold, cured at a temperature of 20 ° C. and a humidity of 80% for 24 hours, then demolded, and cured in water for 6 days to produce a fiber-reinforced cured product. For the cured product thus obtained, the bending strength and the breaking strain were measured, and the number of fibers in the 0.1 mm mesh was counted from the micrograph of the fractured surface,
Dispersion coefficient β obtained from equation (I)

[0040]

[Equation 1]

{Where

[0042]

[Equation 2]

The dispersibility of the fibers was quantified by [μ: average number of fibers contained in sample, n: number of samples (225), Xi: number of fibers contained in each sample]}. The results are shown in Table 4.

[0044]

[Table 4]

Examples 11 to 17 and Comparative Examples 5 to 8 The components shown in Table 5 were mixed and dispersed in water, and a paper product was prepared in the same manner as in Example 1. The compositions of Comparative Example 5 and Comparative Example 8 could not be made into paper. The properties of the fiber used as the component (A) here are the same as those in Table 2 above. A mortar was produced and evaluated in the same manner as in Example 1 by using the thus obtained paper product having a basis weight of 80 g / m ² as a reinforcing fiber material. The results are shown in Table 6.

Comparative Examples 9 to 11 The fibers used as the component (A) in Examples 13, 15 and 16 in Table 5 were added as they were, and mortar was prepared in the same manner as in Example 1 to determine each physical property. . The results are shown in Table 6.

[0047]

[Table 5]

* 4 Component D: Stearyl alcohol (E
O) ₂₀

[0049]

[Table 6]

Examples 18 to 34 and Comparative Example 12 The components shown in Table 7 were used, and Table 8 was used as the component (A).
A fiber-reinforced cured product was produced in the same manner as in Example 1 except that the one having the properties shown in Table 1 was used, and each physical property was determined. The results are shown in Table 9.

Comparative Examples 13 and 14 Fiber-reinforced curing was carried out in the same manner as in Examples 18 and 32, except that each component (A) used in Examples 18 and 32 was used as it was as the reinforcing fiber material. A body was prepared and each physical property was determined. The results are shown in Table 9.

[0052]

[Table 7]

[0053]

[Table 8]

[0054]

[Table 9]

Claims (11)

[Claims] 1. A water-dispersible fiber sheet comprising a paper product of (A) reinforcing fiber, (B) pulp fiber and (C) water-soluble binder. 2. The method according to claim 1, which further comprises (D) a fiber dispersant.
The water-dispersible fiber sheet described. 3. A reinforcing fiber material for a hydraulic inorganic material, comprising a paper product of (A) reinforcing fiber, (B) pulp fiber and (C) water-soluble binder. 4. The method according to claim 1, further comprising (D) a fiber dispersant.
Reinforcing fiber material for hydraulic inorganic material as described. 5. The component (A), the component (B) and the component (C), based on the total weight of the component (A), 20 to 93% by weight,
The water-dispersible fiber sheet according to claim 1, wherein the component (B) is 5 to 80% by weight and the component (C) is 2 to 25% by weight. 6. A component (A), 20 to 93% by weight, based on the total weight of the component (A), the component (B) and the component (C),
The reinforcing fiber material for hydraulic inorganic material according to claim 3, wherein the component (B) is 5 to 80% by weight and the component (C) is 2 to 25% by weight. 7. A component 20 to 9 based on the total weight of component (A), component (B), component (C) and component (D).
3% by weight, component (B) 4.99-80% by weight, component (C) 1.99-25% by weight and component (D) 0.01-10.
The water-dispersible fiber sheet according to claim 2, wherein the content is wt%. 8. The components (A) 20 to 9 based on the total weight of the components (A), (B), (C) and (D).
3% by weight, component (B) 4.99-80% by weight, component (C) 1.99-25% by weight and component (D) 0.01-10.
The reinforcing fiber material for hydraulic inorganic material according to claim 4, which is in a weight percentage. 9. The water-dispersible fiber sheet according to claim 2, wherein the fiber dispersant is a surfactant having an HLB of 5 to 25. 10. The reinforcing fiber material for hydraulic inorganic material according to claim 4, wherein the fiber dispersant is a surfactant having an HLB of 5 to 25. 11. A fiber reinforced characterized by kneading and hardening the reinforcing fiber material for hydraulic inorganic material according to any one of claims 3, 4, 6, 8 and 10 with at least the hydraulic inorganic material and water. A method for producing a cured product.