Laminated molded plate and its manufacturing method

Abstract

The present invention relates to a blast furnace slag layered molded plate constituted of at least two molded plates formed of a curable composition comprising: (A) an aluminosilicate source; (B) alkali metal hydroxide; (C) cellulose fibers; and (D) alkali-resistant fibers other than cellulose fibers, The aluminosilicate source (A) includes blast furnace slag, and the content of the blast furnace slag having a specific surface of 1000 cm2 / g to 9000 cm2 / g is greater than 55 mass% but no greater than 90 mass% with respect to the total solid content of the curable composition.

Description

[Technical Field]

[0001] The present invention relates to a laminated molded plate and a method for producing the same. [Background technology]

[0002] Cement-based paperboards have traditionally been produced by forming sheets from a slurry of cement and fiber suspended in an aqueous medium through a mesh, followed by curing and hardening. Due to its versatility, paperboards are widely used in a wide range of fields, particularly in the construction industry for ceilings, interior and exterior materials, flooring, and other applications. However, cement production requires a significant amount of energy, and the associated large amounts of carbon dioxide emissions are a concern. In response, inorganic polymers produced by reacting aluminosilicates with alkali metal silicates have recently been explored. Compared to cement-based materials, these inorganic polymers have superior durability and acid resistance, and emit significantly less carbon dioxide from the raw material to the finished product. Therefore, they have attracted attention as environmentally friendly materials.

[0003] For example, Patent Document 1 describes an inorganic board that is a hardened mat formed by dehydrating a slurry containing, relative to the total solid content, 30 to 53 mass% of blast furnace slag, 2 to 5 mass% of gypsum having an average particle size of 200 to 2000 μm, 5 to 11 mass% of alkaline material, 5 to 15 mass% of reinforcing fiber, and 31 to 50 mass% of inorganic admixture, and in which the mass ratio of blast furnace slag:gypsum:alkaline material is 1:0.05 to 0.15:0.15 to 0.35. Patent Document 2 describes a paper sheet containing 1.0 to 2.0 mass% of polyvinyl alcohol fibers with a cross-sectional degree of 40 to 70% and 2.0 to 4.0 mass% of eucalyptus pulp with a freeness of 100 to 500 ml, based on the total solid content, and having an interlayer adhesion strength of 2.0 N / mm 2 The document also describes a non-asbestos hydraulic sheet characterized by a dimensional change rate of 0.25% or less. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-216534 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-076874 [Patent Document 3] International Publication No. 2019 / 131321 Brochure Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is still a demand for non-cement based paperboards with better properties. Patent Document 1 uses blast furnace slag as an environmentally friendly raw material, but the amount of blast furnace slag used is small, resulting in low bending strength, and further improvement in dimensional stability is also required. Patent Document 3 describes a molded article formed from a curable composition containing (A) at least one aluminosilicate source, (B) an alkali metal hydroxide, (C) a calcium ion source, and (D) an alkali-resistant fiber, where the aluminosilicate source (A) contains a specific aluminosilicate source. This molded article is produced by a molding method such as a casting method, a dehydration molding method, an injection molding method, or an extrusion molding method, and does not cover paper-formed plates produced by a paper-forming method. In view of the above circumstances, an object of the present invention is to provide a fiber-reinforced laminated molded plate having high bending strength, high impact strength and high dimensional stability. [Means for solving the problem]

[0006] The present inventors have conducted extensive research into laminated molded plates in order to solve the above problems, and as a result have completed the present invention. That is, the present invention includes the following preferred embodiments. [1] A laminated molded plate comprising two or more molded plates formed from a curable composition comprising (A) an aluminosilicate source, (B) an alkaline metal hydroxide, (C) cellulosic fibers, and (D) alkali-resistant fibers other than cellulosic fibers, wherein the aluminosilicate source (A) contains blast furnace slag, and the blast furnace slag has a specific surface area of ​​1000 cm 2 / g or more, 9000cm 2 / g or less, based on the total solid content of the hardenable composition, the blast furnace slag content is more than 55 mass % and 90 mass % or less. [2] The laminated molded plate according to [1] above, wherein the content of the alkaline metal hydroxide (B) is 3% by mass or more and 45% by mass or less based on the total solid content of the curable composition. [3] The laminated molded board according to [1] or [2] above, wherein the content of the cellulosic fiber (C) is 0.5 mass % or more and 15 mass % or less based on the total solid content of the laminated molded board. [4] The laminated molded board according to any one of [1] to [3], wherein the content of the alkali-resistant fiber (D) other than cellulosic fiber is 0.1 mass % or more and 5 mass % or less based on the total solid content of the laminated molded board. [5] The laminated molded plate according to any one of [1] to [4], wherein the aluminosilicate source (A) further contains at least one selected from the group consisting of fly ash, metakaolin, and red mud in a content of 1 mass % or more and 35 mass % or less relative to the total solid content of the hardenable composition. [6] The laminated molded plate according to any one of the above [1] to [5], wherein the alkaline metal hydroxide (B) is slaked lime. [7] The laminated molded board according to any one of the above [1] to [6], wherein the cellulosic fiber (C) is pulp. [8] The laminated molded board according to any one of [1] to [7], wherein the alkali-resistant fibers (D) other than cellulosic fibers have an average fiber diameter of 100 μm or less and an aspect ratio of 50 or more and 2000 or less. [9] The laminated molded board according to any one of [1] to [8], wherein the alkali-resistant fiber (D) other than cellulose-based fiber is at least one selected from the group consisting of polyvinyl alcohol-based fiber, polyethylene fiber, polypropylene fiber, acrylic fiber, aramid fiber, and nylon fiber.

[10] The impact strength of the laminated plate measured in accordance with JIS K 7111 is 2 kJ / m 2 The laminated molded plate according to any one of the above [1] to [9].

[11] A step of preparing a curable composition by mixing an aluminosilicate source (A), an alkaline metal hydroxide (B), a cellulose-based fiber (C), an alkali-resistant fiber other than a cellulose-based fiber (D), and water; A step of obtaining a molded plate by a papermaking method using the obtained curable composition; and A process of stacking two or more of the obtained molded plates A method for producing the laminated molded plate according to any one of the above [1] to

[10] , comprising:

[12] The method according to

[11] above, wherein the step of obtaining a molded plate by the papermaking method includes papermaking the curable composition using a cylinder. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a fiber-reinforced laminated molded plate having high bending strength, high impact strength and high dimensional stability. DETAILED DESCRIPTION OF THE INVENTION

[0008] The laminated molded plate of the present invention is a laminated molded plate comprising two or more molded plates formed from a curable composition comprising (A) an aluminosilicate source, (B) an alkaline metal hydroxide, (C) cellulosic fibers, and (D) alkali-resistant fibers other than cellulosic fibers. The aluminosilicate source (A) contains blast furnace slag and has a specific surface area of ​​1000 cm. 2 / g or more, 9000cm 2 The content of blast furnace slag, which is not more than 55% by mass and not more than 90% by mass, is based on the total solid content of the hardenable composition.

[0009] <(A) Aluminosilicate Source> The aluminosilicate source contains aluminosilicate (xM2O·yAl2O3·zSiO2·nH2O, where M is an alkali metal) as its main component. Here, the term "main component" refers to the component with the largest mass in the aluminosilicate source. When the aluminosilicate source comes into contact with a highly alkaline solution (an aqueous solution of alkaline metal hydroxide (B)), cations such as aluminum and silicon are eluted, and these undergo polycondensation to form a strong SiO4·AlO4 polymer network.

[0010] The aluminosilicate source (A) used in the present invention includes blast furnace slag, which is a waste product generated in the iron-making process.

[0011] The present inventors have found that if the specific surface area of ​​the blast furnace slag is too small, there are few reaction sites for the blast furnace slag, and as a result, the hardening reaction does not proceed sufficiently, while if the specific surface area of ​​the blast furnace slag is too large, the average particle size of the blast furnace slag is small, and for example, when a laminated molded board is produced by a papermaking method, the blast furnace slag is not captured by a papermaking screen, and as a result, the proportion of blast furnace slag in the solid content of the papered board is thought to be reduced. Furthermore, as a result of detailed studies on blast furnace slag, the present inventors have found that in a laminated molded board comprising two or more molded boards formed from a curable composition containing components (A) to (D), a hardening reaction of 1000 cm 2 / g or more, 9000cm 2It was found that when the content of blast furnace slag having a specific surface area of ​​0.1g or less is greater than 55% by mass and less than 90% by mass relative to the total solid content of the curable composition, the laminated molded board has high bending strength, high impact strength, and high dimensional stability. If the content is 55% by mass or less, it is difficult for the laminated molded board to have the desired bending strength, impact strength, and dimensional stability. On the other hand, if the content is higher than 90% by mass, it is difficult for the laminated molded board to have the desired bending strength, impact strength, and dimensional stability. This is thought to be because the optimal blending ratio of the alkaline metal hydroxide (B), cellulose-based fiber (C), and alkali-resistant fiber (D) cannot be obtained due to the content being too high. However, the above is merely speculation, and the present invention is not limited to these action mechanisms.

[0012] Furthermore, the specific surface area is 1000 cm 2 Even if the curable composition contains more than 55 mass % of blast furnace slag having a specific surface area of ​​less than 9000 cm / g, it is difficult to obtain a laminated molded plate having the desired bending strength, impact strength, and dimensional change rate. 2 Even if the curable composition contains blast furnace slag having a molecular weight greater than 1 / g in an amount of 60 mass % or more relative to the total solid content of the curable composition, it is difficult to obtain a laminated molded plate having the desired bending strength, impact strength, and dimensional change rate.

[0013] The content of the blast furnace slag having a specific specific surface area is preferably 60% by mass or more, more preferably 62% by mass or more, even more preferably 65% ​​by mass or more, particularly preferably 68% by mass or more, and preferably 85% by mass or less, more preferably 82% by mass or less, even more preferably 80% by mass or less, particularly preferably 75% by mass or less. When the content is above the lower limit and below the upper limit, for example, when a laminated molded board is produced by a papermaking method, the solid content of the papered blast furnace slag having sufficient reaction sites is contained in a sufficient proportion, and optimal blending ratios of the alkaline metal hydroxide (B), cellulosic fiber (C), and alkali-resistant fiber (D) are obtained. As a result, the produced laminated molded board is likely to have higher bending strength, higher impact strength, and higher dimensional stability.

[0014] The specific surface area of ​​the blast furnace slag contained in an amount of more than 55 mass% and not more than 90 mass% based on the total solid content of the hardenable composition is preferably 2000 cm 2 / g or more, more preferably 3000 cm 2 / g or more, preferably 8000 cm 2 / g or less, more preferably 7000 cm 2 / g or less. When the specific surface area of ​​the blast furnace slag is equal to or greater than the lower limit and equal to or less than the upper limit, the blast furnace slag is likely to have sufficient reaction sites and a suitable average particle size, and as a result, the laminated plate produced is likely to have higher bending strength, higher impact strength, and higher dimensional stability. The specific surface area of ​​the blast furnace slag can be adjusted to be equal to or greater than the lower limit and equal to or less than the upper limit, for example, by crushing and classifying the blast furnace slag and using a specific fraction. The specific surface area of ​​the blast furnace slag can be measured, for example, by laser diffraction / scattering.

[0015] Blast furnace slag is commercially available and has a 1000cm 2 / g or more, 9000cm 2 Commercially available products having a specific surface area of ​​1000 nm / g or less may be used alone or in combination of two or more.

[0016] Blast furnace slag includes crystalline slowly cooled slag and amorphous granulated slag, both of which can be used in the present invention. Granulated slag is preferred because it can further improve the strength of the laminated plate or promote curing.

[0017] Suitable examples of aluminosilicate sources (A) other than blast furnace slag having a specific specific surface area include industrial wastes such as fly ash, red mud, and sewage sludge incineration ash; natural aluminosilicate minerals and their calcined products (e.g., metakaolin); and volcanic ash. These substances are commercially available, and in the present invention, they may be used alone or in combination of two or more. Furthermore, the curable composition of the present invention may be made of a material having a specific surface area of ​​1000 cm or more, as long as the effect of the present invention is not impaired. 2 / g and / or specific surface area of ​​blast furnace slag less than 9000 cm 2 / g or more of blast furnace slag.

[0018] In one embodiment of the present invention, the aluminosilicate source (A) further comprises, in addition to blast furnace slag having a specific specific surface area, at least one selected from the group consisting of fly ash, metakaolin, and red mud, in a content of preferably 1% by mass or more and preferably 35% by mass or less, based on the total solid content of the curable composition. This embodiment tends to increase the density of the cured body compared to when blast furnace slag is used alone as the aluminosilicate source (A), making it easier to obtain a laminated plate with higher bending strength, higher impact strength, and higher dimensional stability. In this embodiment, the content is more preferably 3% by mass or more, even more preferably 4% by mass or more, even more preferably 5% by mass or more, particularly preferably 6% by mass or more, and more preferably 34% by mass or less, even more preferably 33% by mass or less, even more preferably 32% by mass or less, and particularly preferably 30% by mass or less (e.g., 28% by mass or less, 26% by mass or less, 24% by mass or less, 22% by mass or less, 20% by mass or less, or 18% by mass or less). In a preferred embodiment, the content is preferably 15% by mass or less, more preferably 13% by mass or less, even more preferably 12% by mass or less, and particularly preferably 10% by mass or less. When fly ash is contained as the aluminosilicate source (A), the content of the fly ash is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 4% by mass or more, and is preferably 25% by mass or less, more preferably 23% by mass or less, even more preferably 21% by mass or less, even more preferably 15% by mass or less, particularly preferably 13% by mass or less, and particularly preferably 12% by mass or less, based on the total solids content of the curable composition. The content of the fly ash may be 5% by mass or more, 6% by mass or more, or 8% by mass or more, or may be 7% by mass or less, or may be 6% by mass or less.When red mud is included as the aluminum silicate source (A), the content of red mud is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 4% by mass or more, even more preferably 5% by mass or more, even more preferably 7% by mass or more, particularly preferably 9% by mass or more, and especially preferably 11% by mass or more, and is preferably 35% by mass or less, more preferably 33% by mass or less, even more preferably 30% by mass or less, even more preferably 28% by mass or less, particularly preferably 25% by mass or less, and especially preferably 20% by mass or less, based on the total solids content of the curable composition. The content of red mud may be 15% by mass or more or 20% by mass or more, or may be 15% by mass or less, 10% by mass or less, 8% by mass or less, or 6% by mass or less. The content of the blast furnace slag having a specific specific surface area is preferably 56% by mass or more, more preferably 57% by mass or more, even more preferably 58% by mass or more, even more preferably 60% by mass or more, and particularly preferably 62% by mass or more (in one embodiment, for example, 64% by mass or more, preferably 67% by mass or more, more preferably 70% by mass or more), and is preferably 87% by mass or less, more preferably 84% by mass or less, even more preferably 82% by mass or less, and even more preferably 78% by mass or less (in one embodiment, for example, 77% by mass or less), relative to the total solid content of the hardenable composition. When the content is at least the lower limit and at most the upper limit, the above-mentioned effect of adding at least one selected from the group consisting of fly ash, metakaolin, and red mud is easily obtained.

[0019] <(B) Alkaline metal hydroxide> The alkaline metal hydroxide (B) used in the present invention exhibits high alkalinity in water, and upon contact with the aluminosilicate source (A), activates it and dissolves cations such as Al and Si.

[0020] Examples of the alkaline metal hydroxide (B) include slaked lime, quicklime, and sodium hydroxide. From the viewpoint of easily avoiding the problem of metal hydroxides leaking out or being diluted in the process circulating water in the papermaking method, it is preferable to use slaked lime as the alkaline metal hydroxide (B).

[0021] The content of the alkaline metal hydroxide (B) is preferably 3% by mass or more, more preferably 4% by mass or more, even more preferably 6% by mass or more, even more preferably 7% by mass or more, particularly preferably 8% by mass or more, and more preferably 45% by mass or less, even more preferably 43% by mass or less, and particularly preferably 41% by mass or less, based on the total solid content of the curable composition. In a preferred embodiment, the content is preferably 10% by mass or more, preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 22% by mass or less, and particularly preferably 20% by mass or less. When the content is at least the lower limit and at most the upper limit, the produced laminated molded plate is likely to have higher bending strength, higher impact strength, and higher dimensional stability.

[0022] <(C) Cellulose-based fibers> The cellulosic fibers (C) used in the present invention have the effect of increasing the bending strength and impact strength of the laminated molded plate.

[0023] Examples of the cellulosic fiber (C) include natural cellulosic fibers such as rayon fiber (including polynosic rayon fiber and organic solvent-based cellulosic fiber), acetate fiber, and natural pulp (wood pulp, cotton linter pulp, hemp, pulp, etc.). Among these, it is preferable to use natural pulp, and it is more preferable to use pulp, from the viewpoint of easily increasing the yield rate in the cylinder molding process during papermaking. Therefore, in a preferred embodiment of the present invention, the cellulosic fiber (C) is pulp.

[0024] The pulp may be beaten or unbeaten. From the viewpoint of easily obtaining the desired bending strength and impact strength, it is preferable to use beaten pulp, and it is more preferable to use pulp having a CSF value of 50 to 400 mL, more preferably 100 to 150 mL, as measured in accordance with the Canadian standard type of freeness test method JIS P8121-1976.

[0025] A wide variety of pulps can be used. Examples of pulps include conifers, hardwoods, Manila hemp, Mitsumata, paper mulberry, gampi, salago, mulberry, straw, bamboo, reeds, sabai, larang grass, esparto, bagasse, sisal, kenaf, linter, banana, and recycled paper. Examples of conifers include those of the Cedaraceae, Pinaceae, Cupressaceae, and Araucaria families. Examples of hardwoods include those of the Ulmaceae, Fagaceae, Myrtaceae, Cerifera, Oleaceae, Rutaceae, Birchaceae, Mapleaceae, Juglandaceae, Tiliaceae, Araliaceae, Sapotaceae, Celastraceae, Apocynaceae, Verbenaceae, Magnoliae, and Sterculiaceae families. These pulps may be bleached or unbleached. The pulps may be used alone or in combination of two or more.

[0026] The content of the cellulosic fiber (C) is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, particularly preferably 3% by mass or more, and more preferably 15% by mass or less, more preferably 10% by mass or less, even more preferably 9% by mass or less, and particularly preferably 5% by mass or less, based on the total solid content of the laminated molded board. If the content is above the lower limit, for example, when producing the laminated molded board by a papermaking method, blast furnace slag is more likely to be captured by the papermaking screen, making it easier to achieve a good yield rate, and at the same time, a sufficient content of blast furnace slag is more likely to be contained in the papered solid content, making it easier to achieve the desired bending strength and impact strength of the laminated molded board. Furthermore, if the content is below the upper limit, problems such as a decrease in the water resistance of the laminated molded board or a decrease in the effect of inhibiting the penetration of corrosive substances (chlorine, carbon dioxide, various organic acids such as sulfate ions) are more likely to be avoided.

[0027] <(D) Alkali-resistant fibers other than cellulosic fibers> The alkali-resistant fiber (D) other than cellulosic fiber used in the present invention has the effect of increasing the bending strength and impact strength of the laminated molded board. It has been found that the reinforcing effect of the fibers can be synergistically improved by using the cellulosic fiber (C) in combination with the alkali-resistant fiber (D) other than cellulosic fiber (hereinafter sometimes abbreviated as "alkali-resistant fiber (D)").

[0028] The alkali-resistant fiber (D) may be inorganic or organic, as long as it has chemical resistance to alkali. Examples of alkali-resistant inorganic fibers include alkali-resistant glass fibers and carbon fibers. Examples of alkali-resistant organic fibers include various alkali-resistant fibers such as polyvinyl alcohol (hereinafter sometimes referred to as PVA) fibers, polyolefin fibers (e.g., polyethylene fibers and polypropylene fibers), ultra-high molecular weight polyethylene fibers, polyamide fibers (e.g., polyamide 6, polyamide 6,6, and polyamide 6,10), aramid fibers (e.g., para-aramid fibers), polyparaphenylene benzobisoxazole fibers (e.g., polyparaphenylene benzoxazole (PBO) fibers), nylon fibers, acrylic fibers, polyphenylene sulfide fibers (PPS fibers), and polyether ether ketone fibers (PEEK fibers). These alkali-resistant fibers may be used alone or in combination.

[0029] Among these, polyvinyl alcohol-based fibers, polyethylene fibers, polypropylene fibers, acrylic fibers, aramid fibers, and nylon fibers are preferably used because they can easily impart excellent reinforcement to the laminated plate and can be produced at low cost. Therefore, in one embodiment of the present invention, the alkali-resistant fiber (D) other than cellulose-based fibers is preferably at least one selected from the group consisting of polyvinyl alcohol-based fibers, polyethylene fibers, polypropylene fibers, acrylic fibers, aramid fibers, and nylon fibers.

[0030] The average fiber diameter of the alkali-resistant fiber (D) is preferably 100 μm or less, more preferably 80 μm or less, even more preferably 50 μm or less, and preferably 3 μm or more, more preferably 5 μm or more, even more preferably 7 μm or more. When the average fiber diameter of the alkali-resistant fiber (D) is the above-mentioned upper limit or less, such alkali-resistant fiber has sufficient fiber strength and can be easily produced industrially and stably. When the average fiber diameter of the alkali-resistant fiber (D) is the above-mentioned lower limit or more, the fibers are easily dispersed more uniformly in the polymer matrix. Herein, in the present invention, the polymer matrix (hereinafter sometimes referred to as "matrix") means the polymer portion that binds the alkali-resistant fiber in the laminated plate.

[0031] From the viewpoint of easily achieving both good dispersibility of the fibers in the curable composition and good reinforcing properties after curing of the curable composition, the aspect ratio of the alkali-resistant fiber (D) is preferably at least 50, more preferably at least 150, and even more preferably at least 200, and is preferably at most 2000, more preferably at most 1200, and even more preferably at most 800. Here, in the present invention, the aspect ratio means the ratio (L / D) of the average fiber length L to the average fiber diameter D.

[0032] The average fiber diameter and aspect ratio of the alkali-resistant fiber (D) can be determined in accordance with JIS L 1015 "Test method for chemical fiber staple (8.5.1)".

[0033] The average fiber length of the alkali-resistant fiber (D) is preferably 0.5 to 20 mm, more preferably 1 to 15 mm, from the viewpoint of easily achieving both good dispersibility of the fiber in the curable composition and good reinforcing properties of the curable composition after curing.

[0034] The tensile strength of the alkali-resistant fiber (D) in the present invention is preferably 3 cN / dtex or more, more preferably 5 cN / dtex or more, and particularly preferably 7 cN / dtex or more. When the tensile strength of the alkali-resistant fiber is equal to or greater than the above lower limit, the reinforcing performance of the laminated plate is more easily improved. The upper limit of the tensile strength of the alkali-resistant fiber (D) in the present invention is appropriately set depending on the type of fiber, but is, for example, 30 cN / dtex or less. The tensile strength can be determined in accordance with JIS L 1015 "Test method for chemical fiber staple (8.5.1)."

[0035] When a PVA-based fiber, such as a vinylon fiber, is used as the alkali-resistant fiber (D), the PVA-based fiber may have the following properties. The degree of polymerization of the PVA-based polymer constituting the PVA-based fiber can be appropriately selected depending on the purpose and is not particularly limited. In consideration of the mechanical properties of the resulting fiber, the average degree of polymerization of the PVA-based polymer determined from the viscosity of an aqueous solution at 30°C is preferably about 500 to 20,000, more preferably about 800 to 15,000, and particularly preferably about 1,000 to 10,000. Among these, from the viewpoint of the strength of the resulting fiber, the average degree of polymerization of the PVA-based polymer is preferably 1,000 or more, more preferably 1,200 or more, more preferably 1,500 or more, and particularly preferably 1,750 or more. The PVA-based polymer may be a medium-degree of polymerization product with an average degree of polymerization of 1,000 to less than 3,000, or a high-degree of polymerization product with an average degree of polymerization of 3,000 or more.

[0036] The degree of saponification of the PVA-based polymer can also be appropriately selected depending on the purpose and is not particularly limited. From the viewpoint of the mechanical properties of the obtained fiber, the degree of saponification of the PVA-based polymer may be, for example, 95 mol% or more, preferably 98 mol% or more. The degree of saponification of the PVA-based polymer may be 99 mol% or more, or may be 99.8 mol% or more. When the degree of saponification of the PVA-based polymer is equal to or greater than the above-mentioned lower limit, the obtained fiber is likely to have good mechanical properties, processability, production costs, etc.

[0037] The PVA-based fibers used in the present invention are produced by dissolving such a PVA-based polymer in a solvent, spinning it by either a wet, dry-wet, or dry method, and then hot-drawing it. Wet spinning is a method in which the spinning dope is directly discharged from a spinning nozzle into a solidification bath. Dry-wet spinning is a method in which the spinning dope is once discharged from a spinning nozzle into air or an inert gas at a given distance and then introduced into a solidification bath. Dry spinning is a method in which the spinning dope is discharged into air or an inert gas. After spinning, the PVA-based fibers may be stretched as necessary. Furthermore, they may be subjected to acetalization or other treatments commonly performed on PVA-based fibers.

[0038] The solvent used in the spinning solution for PVA-based fibers is not particularly limited as long as it is capable of dissolving PVA. For example, water, dimethyl sulfoxide (DMSO), dimethylformamide, dimethylacetamide, and polyhydric alcohols (e.g., glycerin, ethylene glycol, triethylene glycol, etc.) may be used alone or in combination. In the present invention, when wet spinning is performed, water or an organic solvent is preferably used as the solvent. Among these, water and DMSO are particularly preferred from the viewpoints of ease of supply and environmental impact. The polymer concentration in the spinning solution varies depending on the composition and degree of polymerization of the PVA-based polymer and the type of solvent, but is generally 6 to 60% by mass.

[0039] The above solvents may also be used in dry spinning, and in that case, either water or an organic solvent may be used.

[0040] The spinning dope may contain additives other than the PVA polymer depending on the purpose, as long as the effects of the present invention are not impaired. Examples of the additives include boric acid, surfactants, antioxidants, decomposition inhibitors, antifreeze agents, pH adjusters, masking agents, colorants, and oils.

[0041] The solvent used in the solidification bath may be selected appropriately depending on the type of solvent used in the spinning dope. When the spinning dope is an aqueous solution, the solidification bath may be an aqueous solution of an inorganic salt (e.g., sodium sulfate, ammonium sulfate, sodium carbonate, sodium hydroxide, etc.) capable of solidifying a PVA-based polymer, or an alkaline aqueous solution. When the spinning dope is an organic solvent solution, the solidification bath may be an organic solvent capable of solidifying a PVA-based polymer, such as an alcohol (e.g., methanol, ethanol, propanol, butanol, etc.), or a ketone (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.).

[0042] In the present invention, PVA fibers obtained by dry spinning or PVA fibers obtained by wet spinning from a spinning dope containing water or an organic solvent as the solvent are preferred from the viewpoint of fiber tensile strength.

[0043] In order to extract and remove the solvent of the spinning dope from the solidified raw yarn, the raw yarn may be passed through an extraction bath, and the raw yarn may be wet-stretched simultaneously during extraction. After wet stretching, the fiber may be dried and, if necessary, further subjected to hot stretching. When stretching is performed, the total stretch ratio (the product of the wet stretching ratio and the stretch ratio after drying) may be, for example, 5 to 25 times, preferably about 8 to 20 times.

[0044] Commercially available fibers may be used as the alkali-resistant fiber (D), and examples thereof include organic fibers such as polyvinyl alcohol fibers manufactured by Kuraray Co., Ltd., polypropylene fibers manufactured by Daiwabo Co., Ltd., and nylon fibers manufactured by Toray Industries, Inc., and inorganic fibers such as glass fibers manufactured by Nippon Electric Glass Co., Ltd. and Pacific Materials Corporation.

[0045] In one embodiment of the present invention, the content of the alkali-resistant fiber (D) is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, and preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 3% by mass or less, based on the total solids content of the laminate molded plate. When the content of the alkali-resistant fiber (D) is equal to or greater than the above-mentioned lower limit and equal to or less than the above-mentioned upper limit, the manufactured laminate molded plate is likely to have higher bending strength and higher impact strength. The content of the alkali-resistant fiber (D) in the laminate molded plate can be measured by the following procedure. First, the laminate molded plate is dried at 105°C until it reaches a constant weight and then weighed (W1 (g)). Next, the laminate molded plate is pulverized in a mortar, and water is added to the pulverized product, followed by filtration through a wire mesh (e.g., a 55-mesh wire mesh) to separate the alkali-resistant fiber (D) and cellulosic fiber (C) from the matrix. The separated alkali-resistant fiber (D) and cellulosic fiber (C) are dried at 105°C until they reach a constant weight, and then immersed in a copper oxide ammonia solution (Kishida Chemical Co., Ltd.) for fiber identification to remove the cellulosic fiber (C), dissolving the cellulosic fiber (C) and separating it from the alkali-resistant fiber (D). The separated alkali-resistant fiber (D) is dried at 105°C until it reaches a constant weight, and then weighed (W2 (g)). The content of alkali-resistant fiber (D) in the laminated board is calculated using the following formula. Content of alkali-resistant fiber (D) in laminated board = (W2 / W1) x 100

[0046] <(E) Other powders> The laminated molded board of the present invention may further contain, as other powder (E), a powder other than the aluminosilicate source (A). Examples of other powder (E) include silica fume, calcium carbonate, bentonite, and calcium sulfate derivatives (e.g., gypsum dihydrate, calcium carbonate-extracted gypsum, α-type or β-type hemihydrate gypsum, and anhydrous gypsum), which may be used alone or in combination of two or more. It is preferable for the laminated molded board to contain silica fume, as this makes it easier to achieve better dimensional stability in the laminated molded board.

[0047] When the laminated molded board of the present invention contains other powders (E), the content thereof is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, particularly preferably 3% by mass or more, and is preferably 15% by mass or less, more preferably 13% by mass or less, even more preferably 10% by mass or less, particularly preferably 8% by mass or less, based on the total solid content of the laminated molded board. When the content is not less than the lower limit and not more than the upper limit, the effects of adding the other powders (E) described above can be easily obtained.

[0048] <(F) Slag stimulant> The hardened body of the present invention may further contain a slag stimulant (F). Adding a slag stimulant (F) to the hardenable composition of the present invention makes it easier to obtain a hardened body with higher bending strength. Examples of the slag stimulant (F) include aluminum sulfate, calcium hydroxide, sodium sulfate, and sodium aluminate, which may be used alone or in combination of two or more. Among these, from the viewpoint of making it easier to obtain a hardened body with higher bending strength, it is preferable that the hardened body contains one or more selected from the group consisting of aluminum sulfate, calcium hydroxide, and sodium aluminate.

[0049] When the hardened body of the present invention contains a slag stimulant (F), its content is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, even more preferably 1 mass% or more, particularly preferably 1.5 mass% or more, based on the total solid content of the hardened body, and is preferably 6 mass% or less, more preferably 5 mass% or less, and even more preferably 4 mass% or less. When the content is at least the lower limit and at most the upper limit, the effects of adding the slag stimulant (F) described above can be easily obtained.

[0050] The thickness of the laminated molded plate can be selected appropriately depending on the application, but is usually 4 mm or more and 30 mm or less. When the laminated molded plate is used as a wall material, for example, the thickness of the laminated molded plate is preferably 4 mm or more and 20 mm or less, and when used as a floor material, the thickness of the laminated molded plate is preferably 8 mm or more and 30 mm or less. The thickness of the laminated molded plate can be measured by the method described in the examples below.

[0051] The bulk density of the laminated molded board can be selected appropriately depending on the application, but it is usually 0.5 g / cm 3 More than 2.0g / cm 3 The bulk density of the laminated plate is preferably 0.8 g / cm or less. 3 More preferably, 1.0 g / cm 3 or more, preferably 1.8 g / cm 3 or less, more preferably 1.6 g / cm 3 The bulk specific gravity of the laminated molded plate can be measured by the method described in the Examples below.

[0052] The impact strength of the laminated plate measured in accordance with JIS K 7111 is preferably 2 kJ / m 2 More preferably, 2.5 kJ / m 2 More preferably, 3 kJ / m 2 The upper limit of the impact strength is not particularly limited. The impact strength is usually 7 kJ / m 2 When the impact strength is equal to or greater than the lower limit, the laminated molded board is more likely to be prevented from being damaged by impact when used as a wall material, and is more likely to be prevented from being damaged by falling objects when used as a floor material.

[0053] The bending strength of the laminated molded plate measured in accordance with JIS A 1408 is preferably 10 N / mm 2 More preferably, 11N / mm 2 More preferably, 12N / mm 2 More preferably, 13N / mm 2 More than 17N / mm 2 The upper limit of the bending strength is not particularly limited. The bending strength is usually 35 N / mm2 The following is the result.

[0054] <Method of manufacturing laminated molded board> The laminated molded board of the present invention is preferably produced by a papermaking method. Papermaking involves suspending a solid component such as an aluminosilicate and a fibrous component such as cellulosic fiber (C) and alkali-resistant fiber (D) in an aqueous medium to form a curable slurry composition, which is then drawn onto a mesh and molded into a shape. Examples of papermaking methods include the cylinder or fourdrinier method, in which thin plates of the solid component are sequentially laminated to obtain a laminated molded board of the desired thickness, and the flow-on method, in which a concentrated curable composition is used and a certain thickness is achieved by drawing up the plate once or several times. Papermaking methods allow for mechanical, continuous, batch-wise mass production of laminated molded boards, and the resulting laminated molded boards have uniform and stable performance. Furthermore, relatively thin plates, typically about 2 to 30 mm thick, can be produced. Producing such relatively thin plates is extremely difficult using manufacturing methods other than papermaking (e.g., casting).

[0055] The laminated molded plate of the present invention is, for example, A step of preparing a curable composition by mixing an aluminosilicate source (A), an alkaline metal hydroxide (B), a cellulosic fiber (C), an alkali-resistant fiber other than a cellulosic fiber (D), and water; A step of obtaining a molded plate by a papermaking method using the obtained curable composition; and A process of stacking two or more of the obtained molded plates It can be produced by a method comprising:

[0056] When the other powders (E) and slag stimulator (F) that may be used as needed are used, these optional components can be added in the initial mixing step in which the aluminosilicate source (A), alkaline metal hydroxide (B), cellulose-based fiber (C), and alkali-resistant fiber other than cellulose-based fiber (D) are mixed with water. The aluminosilicate source (A), alkaline metal hydroxide (B), cellulosic fiber (C) and alkali-resistant fiber other than cellulosic fiber (D), as well as the other powder (E) and slag stimulant (F) that may be used optionally in this manufacturing method may be those described above in the sections <(A) Aluminosilicate Source>, <(B) Alkaline Metal Hydroxide>, <(C) Cellulosic Fiber>, <(D) Alkali-Resistant Fiber Other Than Cellulosic Fiber>, <(E) Other Powder>, and <(F) Slag Stimulant>, respectively.

[0057] The preparation method in the step of preparing the curable composition is not particularly limited. From the viewpoint of easily obtaining a curable composition in which the solid components are uniformly dispersed, it is preferable to add the cellulose-based fiber (C) to a stirrer containing water and stir, then add the aluminosilicate (A), the alkaline metal hydroxide (B), and, if added, other powder (E) and the slag stimulant (F), and stir, and finally add the alkali-resistant fiber (D). The order of addition of components (A) and (B) and optional components (E) and (F) is not particularly limited. The amount of water is not particularly limited, but from the viewpoint of easily obtaining a uniform curable composition without excessive water, the solids concentration in the step of preparing the curable composition is usually 10% by mass or more and 25% by mass or less.

[0058] As the papermaking method, a cylinder wire method, a Fourdrinier method, or a flow-on method can be used. From the viewpoint of facilitating the production of a wide range of thicknesses from thin to thick, it is preferable to use the cylinder wire method. Therefore, in a preferred embodiment of the present invention, the step of obtaining a molded plate by the papermaking method includes papermaking the curable composition using a cylinder wire.

[0059] In the cylinder mould method, the solids concentration in the process of preparing the curable composition is typically 10% by mass or more and 25% by mass or less. The prepared curable composition is diluted with process circulating water to a solids concentration typically of 3% by mass or more and 10% by mass or less, and the diluted curable composition is supplied to a cylinder mould and drawn into a shaped board. In the cylinder mould method, the solids drawn up using a single cylinder mould or two to six consecutive cylinder moulds are attached to felt to obtain a shaped board, and the shaped boards are laminated until they reach the desired thickness while being wound up on a making roll, making continuous production possible. Other procedures and conditions for the cylinder mould method can be general procedures and conditions.

[0060] In the above manufacturing method, two or more molded plates obtained by the papermaking method are laminated. After laminating them with a making roll until the desired thickness is reached, the laminated molded plate is obtained by dehydration pressing, curing, and drying. The pressure of the dehydration press is usually 20 kg / cm. 2 ~300kg / cm 2 The pressure holding time is usually 10 to 60 minutes. Curing is usually carried out for 8 to 55 hours under conditions of a temperature of 50 to 90°C and a relative humidity of 80 to 100%.

[0061] The drying method is not particularly limited as long as a uniformly dried laminated molded board is obtained. Since the equilibrium moisture content of a laminated molded board (for example, the moisture content reached when stored in a well-ventilated room for 7 days or more) is usually about 6% to about 10%, the board is dried to a moisture content similar to the equilibrium moisture content. The moisture content and equilibrium moisture content of a laminated molded board can be simply measured using a Kett moisture meter. Alternatively, the dried laminated molded board is weighed (W3), and then dried in an air dryer equipped with a stirrer at 105°C until a constant weight is reached. The weight of the laminated molded board is then calculated using the following formula: {(W3-W4) / W4}×100 It can also be calculated by

[0062] The resulting laminated molded plate is based on a curable composition having excellent uniformity due to its specific composition, and therefore has high bending strength, high impact strength, and high dimensional stability. [Example]

[0063] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. The physical properties in the examples and comparative examples were measured or evaluated by the following methods.

[0064] [Thickness measurement] The thickness of the laminated plate was measured at six points using a digital caliper, and the average value was taken as the thickness of the laminated plate.

[0065] [Method for measuring bulk density] The bulk density was measured in accordance with JIS A 5430. Specifically, the laminated molded plate to be measured was placed in an air dryer equipped with a stirrer, and dried at 105°C ± 5°C for 24 hours, after which the bulk density was calculated from the mass and volume of the laminated molded plate.

[0066] [Method for measuring bending strength] Four rectangular test pieces, approximately 180 mm long and 50 mm wide, were cut from the laminated plate to be measured. The test pieces were then dried for 72 hours in an air dryer equipped with a stirrer set at 40°C to maintain a constant moisture content during measurement. The bending strength of each test piece was measured in accordance with JIS A 1408, and the average value was used as the bending strength. Bending strength was measured using a Shimadzu Autograph "AG500-B" under the central loading method, with a bending span of 14.6 cm and a test speed (loading head speed) of 20 mm / min.

[0067] [Method for measuring impact strength] Six rectangular test pieces, approximately 80 mm long and 10 mm wide, were cut from the laminated plate to be measured. The test pieces were then dried for 72 hours in an air dryer equipped with a stirrer at 40°C to maintain a constant moisture content during measurement. The impact strength of each test piece was measured in accordance with JIS K 7111 "Plastics - Test Method for Charpy Impact Strength," and the average value was used as the impact strength. Impact strength was measured using a Charpy (Digital) Impact Tester, Model DG-CB, manufactured by Toyo Seiki Seisakusho Co., Ltd.

[0068] [Measurement method for dimensional change rate] The dimensional change rate of the laminated molded plate was measured in accordance with JIS A 5430. First, the laminated molded plate to be measured was placed in a dryer and maintained at 60°C ± 3°C for 24 hours, after which it was removed. The removed laminated molded plate was placed in a desiccator conditioned with silica gel and left to cool to 20°C ± 1.5°C. Next, milky-colored glass was attached to the laminated molded plate, and marks were inscribed so that the distance between the marks was approximately 140 mm. The length between the marks was measured using a comparator with an accuracy of 1 / 500 mm, and this length was designated L1 (mm). Next, the laminated molded plate was placed on a stand so that its length was horizontal, and the top end of the laminated molded plate was approximately 30 mm below the water surface and immersed in water at 20°C ± 1.5°C. After 24 hours, the laminated molded plate was removed from the water, the water adhering to the surface was wiped off, and the length between the marks was measured again, and this length was designated L2 (mm). The dimensional change rate Y (%) due to water absorption was calculated using the following formula: Length change rate due to water absorption Y={(L2-L1) / L1}×100

[0069] [Example 1] 3% by mass of pulp (NBKP, Cellofiber manufactured by Partex Co., Ltd.) as the cellulose-based fiber (C) was dispersed in water. The resulting dispersion and blast furnace slag (specific surface area: 4000 cm) as the aluminosilicate source (A) were mixed. 280.5% by mass of (g / g) and 5% by mass of fly ash (Shiden Business Co., Ltd.: Shiden Fly Ash Type II), 5% by mass of slaked lime (Kochi Lime Industry Co., Ltd.: Industrial Slaked Lime No. 1) as alkaline metal hydroxide (B), and 5% by mass of silica fume (Tomoe Engineering Co., Ltd.: EFACO Silica Fume) as other powder (E) were mixed in a mixer. 1.5% by mass of PVA1 (Kuraray Co., Ltd.) as alkali-resistant fiber (D) was added to the resulting mixture and further mixed to obtain a curable composition in a slurry form with a solids concentration of 16% by mass. The resulting curable composition was transferred to a constant-rate feeder. The slurry was then fed from the feed tank of the constant-rate feeder to a cylinder press, where the solids concentration was adjusted to 4% by mass using circulating process water. Papermaking was then carried out using a Mini-Hatchek machine. Ten molded sheets obtained in the cylinder press were then stacked on a making roller, and the stacked wet molded sheets were pressed together at 75 kg / cm. 2 The resulting laminated sheet had a thickness of 4.6 mm and a bulk density of 1.35 g / cm. 3 This was cured in a constant temperature and humidity curing device at a temperature of 90°C and saturated humidity (RH 98%) for 48 hours, and then dried in an air dryer equipped with a stirrer at 60°C for 16 hours to obtain a laminated molded plate. The obtained laminated molded plate was evaluated as described above, and the results are shown in Table 2.

[0070] [Examples 2 to 4] Laminated molded plates were produced and evaluated in the same manner as in Example 1, except that the proportion of blast furnace slag and the proportion of alkaline metal hydroxide (B) were changed as shown in Table 2.

[0071] [Examples 5 to 7] Laminated molded boards were produced and evaluated in the same manner as in Example 3, except that the type of alkali-resistant fiber (D) other than the cellulosic fiber was changed as shown in Table 2.

[0072] [Example 8] 4000cm 2 / g specific surface area of ​​6000 cm 2 A laminated molded plate was produced and evaluated in the same manner as in Example 2, except that blast furnace slag having a specific surface area of ​​1 / g was used.

[0073] [Example 9] 4000cm 2 / g specific surface area of ​​6000 cm 2 A laminated molded plate was produced and evaluated in the same manner as in Example 3, except that blast furnace slag having a specific surface area of ​​1 / g was used and PVA2 was used instead of PVA1.

[0074] [Examples 10 to 11] Laminated molded plates were produced and evaluated in the same manner as in Example 9, except that the proportions of blast furnace slag and fly ash were changed as shown in Table 2.

[0075] [Examples 12 to 13] Laminated molded plates were produced and evaluated in the same manner as in Example 11, except that the proportions of blast furnace slag and silica fume were changed as shown in Table 2.

[0076] [Example 14] Laminated molded boards were produced and evaluated in the same manner as in Example 3, except that the proportions of blast furnace slag and pulp were changed as shown in Table 2.

[0077] [Example 15] Laminated molded boards were manufactured and evaluated in the same manner as in Example 6, except that the proportion of blast furnace slag and the proportion of alkali-resistant fiber (D) other than cellulosic fiber were changed as shown in Table 2.

[0078] [Example 16] In addition, silica fume and dihydrate gypsum were added instead of silica fume as the powder (E), and the proportion of blast furnace slag and the proportion of alkaline metal hydroxide (B) were changed as shown in Table 2. Except for this, laminated molded boards were manufactured and evaluated in the same manner as in Example 1.

[0079] [Example 17] Laminated molded boards were manufactured and evaluated in the same manner as in Example 1, except that the proportions of blast furnace slag and alkaline metal hydroxide (B) were changed as shown in Table 2, and instead of mixing the dispersion of cellulose fiber (C) with blast furnace slag and fly ash as the aluminosilicate source (A), slaked lime as the alkaline metal hydroxide (B), and silica fume as the other powder (E) in a mixer, the dispersion of cellulose fiber (C) was mixed with the above materials and aluminum sulfate as a slag stimulant (F) in a mixer.

[0080] [Examples 18 to 19] Laminated molded boards were manufactured and evaluated in the same manner as in Example 2, except that silica fume and dihydrate gypsum were added instead of silica fume as the powder (E), and the proportion of blast furnace slag and the type of alkali-resistant fiber (D) other than cellulosic fiber were changed as shown in Table 2.

[0081] [Examples 20 to 21] In addition, silica fume and dihydrate gypsum were added instead of silica fume as powder (E), the proportion of blast furnace slag, the proportion of alkaline metal hydroxide (B) and the proportion of slag stimulant (F) were changed as shown in Table 2, and the curing temperature and time were changed from 90°C and 48 hours to 60°C and 24 hours. A laminated molded board was manufactured and evaluated in the same manner as in Example 17.

[0082] [Example 22] Laminated molded plates were produced and evaluated in the same manner as in Example 1, except that fly ash and red mud were added instead of fly ash, and the proportions of blast furnace slag and fly ash were changed as shown in Table 2.

[0083] [Example 23] A laminated molded plate was manufactured and evaluated in the same manner as in Example 4, except that fly ash and red mud were added instead of fly ash, and the proportions of blast furnace slag, fly ash, and silica fume were changed as shown in Table 2.

[0084] [Example 24] The proportion of blast furnace slag was changed from 75.5% by mass to 56% by mass, and accordingly, the proportion of fly ash and the proportion of alkaline metal hydroxide (B) were changed as shown in Table 2. Except for this, a laminated molded plate was manufactured and evaluated in the same manner as in Example 8.

[0085] [Comparative Example 1] An attempt was made to produce a laminated molded plate in the same manner as in Example 1, except that the alkaline metal hydroxide (B) was not added and the proportion of blast furnace slag was changed accordingly as shown in Table 2. However, the laminated molded plate did not harden. Therefore, it was not possible to evaluate the laminated molded plate.

[0086] Comparative Example 2 Laminated molded boards were manufactured and evaluated in the same manner as in Example 3, except that no alkali-resistant fiber (D) other than cellulose-based fiber was added and the proportion of blast furnace slag was changed accordingly as shown in Table 2.

[0087] Comparative Example 3 Laminated molded boards were manufactured and evaluated in the same manner as in Example 1, except that the proportion of blast furnace slag was changed from 80.5% by mass to 55% by mass, and accordingly the proportion of alkaline metal hydroxide (B), the proportion of cellulose-based fiber (C), and the proportion of alkali-resistant fiber other than cellulose-based fiber (D) were changed as shown in Table 2.

[0088] Comparative Example 4 4000cm 2 / g specific surface area of ​​800 cm 2 A laminated molded plate was produced and evaluated in the same manner as in Example 3, except that blast furnace slag having a specific surface area of ​​1 / g was used.

[0089] Comparative Example 5 4000cm 2 / g specific surface area of ​​10000 cm 2 A laminated molded plate was produced and evaluated in the same manner as in Example 3, except that blast furnace slag having a specific surface area of ​​1 / g was used.

[0090] Comparative Example 6 Laminated molded boards were manufactured and evaluated in the same manner as in Example 1, except that the proportion of blast furnace slag was changed from 80.5% by mass to 90.5% by mass, and the proportion of fly ash and the proportion of silica fume were changed as shown in Table 2.

[0091] The properties of the fibers used in the examples and comparative examples are shown in the following Table 1. Table 2 also shows the compositions in the examples and comparative examples, as well as the evaluation results of the laminated molded plates. [Table 1]

[0092] [Table 2]

[0093] [Table 3]

[0094] All of the laminated molded plates produced in Examples 1 to 24 had high bending strength, high impact strength, and high dimensional stability.

[0095] On the other hand, the laminated molded plate of Comparative Example 2, to which no alkali-resistant fiber (D) was added, exhibited significantly low bending strength and significantly low impact strength. Specific surface area is 1000cm 2 / g or more, 9000cm 2The laminated molded plate of Comparative Example 3, in which the content of blast furnace slag was 55 mass % or less, based on the total solid content of the hardenable composition, exhibited significantly low impact strength and significantly high dimensional change rate. Specific surface area is 1000cm 2 The laminated molded plate of Comparative Example 4, which contained blast furnace slag of less than 1 / g in an amount of 60 mass % or more based on the total solid content of the hardenable composition, exhibited significantly low bending strength, significantly low impact strength, and high dimensional change rate. Specific surface area is 9000cm 2 The laminated molded plate of Comparative Example 5, which contained blast furnace slag of more than 60 mass % or more than 1 / g based on the total solid content of the hardenable composition, exhibited significantly low bending strength, significantly low impact strength, and high dimensional change rate. Specific surface area is 1000cm 2 / g or more, 9000cm 2 The laminated molded plate of Comparative Example 6, in which the content of blast furnace slag of 1 / g or less was more than 90 mass % relative to the total solid content of the hardenable composition, exhibited significantly low bending strength and high dimensional change rate. [Industrial Applicability]

[0096] The laminated molded board of the present invention has high bending strength, high impact strength, and high dimensional stability, and can therefore be usefully used as a variety of building materials, including, but not limited to, interior and exterior materials, flooring materials, wall materials, ceiling materials, partitions, roofing materials, and roof tiles.

Claims

1. A laminated molded plate comprising two or more molded plates formed from a curable composition comprising (A) an aluminosilicate source, (B) an alkaline metal hydroxide, (C) a cellulose fiber, and (D) an alkali-resistant fiber other than a cellulose fiber, wherein the aluminosilicate source (A) comprises blast furnace slag and has a specific surface area of ​​3000 cm ２ / g or more, 8000cm ２ / g or less, the content of the blast furnace slag is 56 mass% or more and 85 mass% or less based on the total solid content of the hardenable composition, A laminate molded plate, wherein the content of alkaline metal hydroxide (B) is 3 mass% or more based on the total solid content of the curable composition, the content of cellulosic fiber (C) is 2 mass% or more based on the total solid content of the laminate molded plate, and the content of alkali-resistant fiber (D) other than cellulosic fiber is 1.5 mass% or more and 5 mass% or less based on the total solid content of the laminate molded plate.

2. The laminated molded plate according to claim 1, wherein the content of the cellulosic fiber (C) is 2% by mass or more and 15% by mass or less based on the total solid content of the laminated molded plate.

3. 3. The laminated molded plate according to claim 1 or 2, wherein the aluminosilicate source (A) further comprises at least one selected from the group consisting of fly ash, metakaolin, and red mud in a content of 1 mass% or more and 35 mass% or less, based on the total solid content of the curable composition.

4. The laminated molded plate according to any one of claims 1 to 3, wherein the alkaline metal hydroxide (B) is slaked lime.

5. The laminated molded board according to any one of claims 1 to 4, wherein the cellulosic fiber (C) is pulp.

6. The laminated molded plate according to any one of claims 1 to 5, wherein the alkali-resistant fibers (D) other than cellulosic fibers have an average fiber diameter of 100 μm or less and an aspect ratio of 50 or more and 2000 or less.

7. The alkali-resistant fiber (D) other than cellulose-based fiber is at least one selected from the group consisting of polyvinyl alcohol-based fiber, polyethylene fiber, polypropylene fiber, acrylic fiber, aramid fiber, and nylon fiber. The laminated molded board according to any one of claims 1 to 6.

8. The impact strength of the laminated plate measured in accordance with JIS K 7111 is 2 kJ / m ２ The laminated molded plate according to any one of claims 1 to 7.

9. A step of preparing a curable composition by mixing an aluminosilicate source (A), an alkaline metal hydroxide (B), cellulosic fibers (C), alkali-resistant fibers other than cellulosic fibers (D), and water; A step of obtaining a molded plate by a papermaking method using the obtained curable composition; and A step of stacking two or more of the obtained molded plates The method for producing the laminated molded plate according to any one of claims 1 to 8, comprising:

10. The method according to claim 9, wherein the step of obtaining a molded plate by the papermaking method includes papermaking the curable composition using a cylinder.

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