JP2011051804A - Woody cement molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a woody cement molding excellent in dimensional stability and flame retardancy. <P>SOLUTION: The woody cement molding is obtained by molding a woody cement composition containing cement, a woody material, an inorganic fiber, magnesium sulfate, magnesium hydroxide and water to obtain a molded intermediate and aging the molded intermediate in pressurized steam. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wood cement molded body.

  Conventionally, as a wood cement molding, for example, a cement cement containing a wood material such as wood powder or pulp and cement is molded and cured.

  Since such a wood cement molded body contains a wood material, it is relatively lightweight and has a high bending strength and excellent sound insulation. For example, it can be used for interior materials and exterior materials of various buildings. It is used.

  However, such a molded body has a problem that the cement hydrate is carbonated due to the reaction of cement hydrate with carbon dioxide over time, and the molded body may shrink accordingly, that is, dimensional stability is reduced. There is a problem of being inferior.

Therefore, in order to make the dimensional stability of the wood cement molded body excellent, a molded body in which magnesium oxide or magnesium hydroxide is blended and steam-cured under atmospheric pressure has been proposed (Patent Document 1). In addition, a molded body obtained by blending a mineral powder containing magnesium oxide and curing it is proposed (Patent Document 2).

  That is, in the wood cement molded body containing magnesium hydroxide or magnesium oxide as in Patent Document 1 or Patent Document 2, magnesium carbonate generated by the reaction of magnesium hydroxide or the like with carbon dioxide over time expands the molded body. On the other hand, the cemented hydrate carbonated as described above causes the compact to shrink. By canceling out such expansion and contraction, the expansion or contraction of the molded body can be suppressed, and the dimensional stability of the molded body can be relatively good.

  However, this type of wood cement molded body has a relatively low flame retardancy due to the combustibility of the wood material contained therein, and it is also possible to add magnesium hydroxide or magnesium oxide as described above. There is still a problem that the flame retardancy is relatively low.

JP 05-43290 A JP 2001-139384 A

  Therefore, a wood cement molded body excellent in dimensional stability and flame retardancy is desired.

  This invention makes it a subject to provide the wood cement molded object excellent in dimensional stability and a flame retardance in view of the said problem, a request point, etc.

  In order to solve the above-mentioned problems, a wood cement molded body according to the present invention is formed by molding a wood cement composition containing cement, a wood material, inorganic fibers, magnesium sulfate, magnesium hydroxide, and water, followed by pressure steam curing. It is characterized by becoming.

According to the wood cement molded body having the above structure, a cement is obtained by molding a wood cement composition containing cement, a wood material, inorganic fibers, magnesium sulfate, magnesium hydroxide, and water, and curing with pressurized steam. Hydration reaction causes hydrated crystals to grow in the gaps between the woody material or the inorganic fibers. Further, a fibrous magnesium compound [MgSO ₄ .5Mg (OH) ₂ .3H ₂ O] is generated in the gap between the woody material or the inorganic fibers by the reaction of magnesium sulfate and magnesium hydroxide. The cement hydrate and the magnesium compound fix the wood material and the inorganic fiber, and the dimensional stability of the wood cement molded body in a relatively short period can be improved.
Furthermore, while the fibrous magnesium compound can react with carbon dioxide in the air and expand over time, the cement hydrate can react with carbon dioxide over time and contract. As a result, the expansion or contraction of the molded body is suppressed by canceling out such expansion and contraction, and the wood cement molded body has excellent dimensional stability over a relatively long period of time.
The magnesium compound [MgSO ₄ .5Mg (OH) ₂ .3H ₂ O] is an excellent flame retardant, and has excellent flame retardancy of the wood cement molded body together with the non-flammable inorganic fibers. obtain. In addition, the non-flammable magnesium compound is produced in the form of fibers around the wood material by pressurized steam curing, making it difficult to burn the combustible wood material and reducing the flame retardancy of the wood cement molded body. It can be excellent.

  In the wood cement molded body according to the present invention, the wood cement composition preferably contains the inorganic fiber in an amount of 1 to 2 times the mass of the wood material.

  As described above, the wood cement molded body according to the present invention has an effect of being excellent in dimensional stability and flame retardancy.

The powder X-ray diffraction chart of a wood cement molding.

  Hereinafter, an embodiment of a wood cement molded body according to the present invention will be described.

  The wood cement molded body of this embodiment is formed by molding a wood cement composition containing cement, a wood material, inorganic fibers, magnesium sulfate, magnesium hydroxide, and water and curing with pressurized steam.

  The wood cement composition contains cement, wood material, inorganic fibers, magnesium sulfate, magnesium hydroxide, and water, and may further contain siliceous material, slaked lime, and the like.

The cement is not particularly limited, and examples of the cement include ordinary Portland cement, moderately heated Portland cement, low heat Portland cement, early-strength Portland cement, ultra-early strength Portland cement, sulfate-resistant Portland cement, and the like. . Also included are mixed cements such as blast furnace cement, fly ash cement, and silica cement, ultrafast cement such as alumina cement and jet cement, and Irwin cement. In addition, as said cement, the thing single 1 type of these, or the thing which mixed 2 or more types is employable.
The ratio of the cement in the wood cement composition is not particularly limited, but is usually 10 to 15% by mass.

Examples of the wood material include wood pieces, wood wool, wood powder, and pulp. Moreover, as this wooden material, these 1 type individual materials or what mixed 2 or more types is employable.
The ratio of the wood material in the wood cement composition is not particularly limited, but is usually 5 to 20% by mass in terms of dry mass at 105 ° C.

The said inorganic fiber is a fibrous thing containing an inorganic substance, and is nonflammable. The inorganic fiber is not particularly limited in composition, density, fiber length, aspect ratio, and the like, and preferably an inorganic fiber having excellent safety to the human body can be adopted. Examples of the inorganic fiber include glass wool, rock wool, slag wool, ceramic fiber, potassium titanate fiber, wollastonite fiber, apatal gite, and sepiolite. Among these, rock wool and slag wool are preferable in that the nonflammability of the wood cement molded body can be further increased. In addition, as said inorganic fiber, what mixed 1 type of these or 2 types or more is employable.
The ratio of the inorganic fibers in the wood cement composition is not particularly limited, but is preferably 5 to 20% by mass in that the incombustibility of the wood cement molded body can be further enhanced.

  The mass ratio of the wood material (dried material at 105 ° C.) and the inorganic fiber is preferably wood material: inorganic fiber = 1: 1 to 1: 2. That is, it is preferable that the wood cement composition contains the inorganic fiber in an amount of 1 to 2 times the mass of the wood material. When the mass ratio of the inorganic fiber to the wood material is 1 or more, there is an advantage that the flame retardancy of the molded body can be further increased, and when it is 2 or less, the molded body can be easily reduced in weight. There is.

The magnesium sulfate may be an anhydride or a hydrate. Moreover, as said magnesium sulfate, what was produced | generated to the said wood cement composition by mixing magnesium salt and a sulfuric acid may be sufficient.
The amount of the magnesium sulfate is not particularly limited, but is preferably contained in the wood cement composition in an amount of 0.1 to 5.0% by mass in terms of anhydride. More preferably, 0% by mass is contained. By including 0.1% by mass or more of magnesium sulfate in the wood cement composition, there is an advantage that a magnesium compound described later is more easily generated, and by containing 5.0% by mass or less, There exists an advantage that it becomes difficult to precipitate in a wood cement composition.

Moreover, as said magnesium sulfate, what was collect | recovered from the flue gas desulfurization apparatus by the magnesium hydroxide method is employable, for example.
More specifically, such magnesium sulfate was produced by a magnesium hydroxide method having excellent removal efficiency when removing (desulfurization) sulfur oxides contained in exhaust gas discharged from a thermal power plant or the like. Is. The waste liquid containing magnesium sulfate produced by the method has been disposed of by ocean dumping, etc., but because of the large burden on the global environment due to ocean dumping, in Japan, by amending the Waste Disposal Law, After 2007, such magnesium sulfate waste liquid is not allowed to be dumped into the ocean, and there is a demand for a legal and appropriate disposal method for the waste liquid. Therefore, it is preferable to use magnesium sulfate recovered from the flue gas desulfurization apparatus by the magnesium hydroxide method because the waste can be effectively used.

  When employ | adopting the said magnesium sulfate in the aspect of aqueous solution, it is preferable that the density | concentration of magnesium sulfate of such aqueous solution is 3-25 mass% in conversion of an anhydride.

  The magnesium hydroxide may be produced, for example, by reacting magnesium oxide (MgO) with water. That is, the wood cement composition may contain magnesium hydroxide produced by mixing magnesium oxide and reacting with water.

  The magnesium hydroxide is preferably contained in the wood cement composition in an amount of 1.5 to 7.0% by mass. By including 1.5% by mass or more of magnesium hydroxide in the wood cement composition, there is an advantage that a magnesium compound described later is more easily generated, and by containing 7.0% by mass or less, There is an advantage that it is more difficult to precipitate in the wood cement composition.

The magnesium sulfate and the magnesium hydroxide react to become a magnesium compound [MgSO ₄ .5Mg (OH) ₂ .3H ₂ O] by pressurized steam curing. The magnesium compound can expand by reacting with carbon dioxide over time, whereas the cement hydrate contained in the hardened body of the wood cement composition shrinks by reacting with carbon dioxide. To do. Such expansion and contraction are offset, and as a result, the dimensional stability over time of the wood cement molded body can be excellent.

Further, the magnesium compound [MgSO ₄ .5Mg (OH) ₂ .3H ₂ O] is non-flammable and has excellent flame retardancy of the molded body by being contained in the wood cement molded body. It can be.

The mass ratio of the magnesium sulfate to the magnesium hydroxide is preferably magnesium sulfate: magnesium hydroxide = 1: 2 to 1: 3 in terms of anhydride. By such a mass ratio, there is an advantage that the magnesium compound [MgSO ₄ .5Mg (OH) ₂ .3H ₂ O] is more likely to be generated, and the dimensional stability of the wood cement molded body can be further improved. .

The water is not particularly limited, and tap water is usually employed. Moreover, when employ | adopting the said magnesium sulfate aqueous solution as a supply source of magnesium sulfate, the water contained in this aqueous solution can turn into the water contained in a wood cement composition.
The water is preferably contained in an amount of 25 to 75% by mass and more preferably 35 to 45% by mass with respect to the wood cement composition. Moreover, it is preferable that the said water is contained 25-45 mass% with respect to the said wood cement composition in the point of manufacturing a wood cement molding by dry molding or semi-dry molding.

The siliceous body is mainly composed of silicic acid (SiO ₂ ). Examples of the siliceous material include silica powder, fly ash, silica fume, perlite, vermiculite, shirasu, shirasu balloon, diatomaceous earth, minestone, siliceous white clay (acidic white clay), expanded shale, mica (mica), tuff, Rhyolite tuff, acid volcanic rock, ash rich in amorphous silica after burning rice husk or rice straw, calcined clay typified by metakaolin, waste material generated from ceramics (waste tile, Waste bricks, waste ceramics, waste ceramics, etc.) and blast furnace fumes generated during steelmaking. In addition, as this siliceous body, what mixed these 1 type individual materials or 2 types or more is employable.
The size of the siliceous material is not particularly limited, but a size that passes through a sieve having an opening of 100 to 500 μm is preferable.
Moreover, it is preferable that 15-25 mass% of the said siliceous body is contained in the said wood cement composition.

As said slaked lime (calcium hydroxide), industrial grade things, such as special name slaked lime, are employ | adopted, for example.
The slaked lime (calcium hydroxide) can react with the magnesium sulfate, and can form gypsum (calcium sulfate) after the reaction. It is preferable that the said wooden cement composition contains this slaked lime at the point that the produced | generated gypsum (calcium sulfate) suppresses the excessive progress of the hydration reaction of cement.
Moreover, it is preferable that 1-3 mass% of the slaked lime is contained in the wood cement composition.

Mixture A composed of the cement, the woody material, the inorganic fiber, the siliceous body, and the slaked lime, and the mixture B composed of the magnesium sulfate (anhydrous equivalent), the magnesium hydroxide (anhydrous equivalent), and water. Is preferably 25 to 100 parts by mass, more preferably 75 to 95 parts by mass with respect to 100 parts by mass of the mixture A. With such a mass ratio, there is an advantage that a magnesium compound [MgSO ₄ .5Mg (OH) ₂ .3H ₂ O] is more likely to be generated.

  Next, the manufacturing method of the wood cement molding of this embodiment is demonstrated in detail.

The manufacturing method of the wood cement molded body of this embodiment forms a wood cement composition containing cement, wood material, inorganic fiber, magnesium sulfate, magnesium hydroxide and water, and is subjected to pressurized steam curing.
Specifically, in the method for producing a wood cement molded body of this embodiment, a kneading step of kneading a wood cement composition containing cement, a wood material, inorganic fibers, magnesium sulfate, magnesium hydroxide and water, A molding process for molding the mixed wood cement composition and a curing process for curing the molded molding intermediate under pressure steam are performed.

In the kneading step, the cement, the wood material, the inorganic fiber, the magnesium sulfate, the magnesium hydroxide, and water are contained as raw materials, and further, the siliceous body and the wood cement composition that can contain the slaked lime Mix things.
Specifically, for example, by mixing a part of the raw materials other than water, first knead empty, then add the remaining part of the water and raw materials, mix and perform the main kneading to mix the mixing step. Can be implemented.

  In the kneading step, a predetermined amount of magnesium sulfate and a predetermined amount of magnesium hydroxide can be used. Further, as described above, a predetermined amount of magnesium sulfate generated by mixing a predetermined amount of magnesium salt and a predetermined amount of sulfuric acid may be used, and generated by reacting a predetermined amount of magnesium oxide with water. A predetermined amount of magnesium hydroxide may be used.

  In the kneading step, kneading can be performed using a conventionally known general kneading apparatus. That is, for example, mixing can be performed using an apparatus typified by a blade-type mixer such as a paddle mixer, a ribbon mixer, a screw mixer, a Henschel mixer, an Eirich mixer, and an omni mixer.

In the molding step, the wood cement composition kneaded in the kneading step is molded into a predetermined shape to produce a molding intermediate.
As a method for molding the wood cement composition, a conventionally known general method, that is, a papermaking method, a casting method, a press molding method, an injection molding method, an extrusion molding method, or the like can be employed.

  In the curing step, the molded intermediate produced in the molding step is subjected to pressurized steam curing. Specifically, the molding intermediate is cured with steam under a pressure exceeding atmospheric pressure.

Specifically, in the curing step, pressurized steam curing can be performed on the molded intermediate, for example, at 100 to 300 ° C., 2 to 20 atmospheres, and 1 to 20 hours. The pressurized steam curing is preferably performed at 180 ° C. (10 atm) for about 18 hours from the viewpoint that the magnesium compound [MgSO ₄ .5Mg (OH) ₂ .3H ₂ O] can be generated more reliably.
In the curing step, curing can be performed using, for example, an autoclave apparatus.

By performing pressurized steam curing in the curing step, as shown in the following formula (1), magnesium hydroxide causes a hydrothermal reaction with magnesium sulfate, and a fibrous magnesium compound having a relatively large aspect ratio [MgSO ₄ • 5Mg (OH) ₂ .3H ₂ O] crystals are formed.
5Mg (OH) ₂ + MgSO ₄ + 3H ₂ O → MgSO ₄ .5Mg (OH) ₂ .3H ₂ O
Formula (1)

  In the curing step, in order to produce the magnesium compound, theoretically, 1 mol of magnesium sulfate (anhydride) is required for 5 mol of magnesium hydroxide (anhydride). In excess (about 1.05 to 1.10 moles of magnesium sulfate (anhydride) with respect to 5 moles of magnesium hydroxide (anhydride)), the reaction to produce the magnesium compound is more likely to proceed. Thus, the magnesium compound can be generated more reliably. In addition, the magnesium sulfate which was not consumed by the reaction which produces | generates the said magnesium compound can be consumed by reacting with cement, slaked lime, etc.

The magnesium compound [MgSO ₄ .5Mg (OH) ₂ .3H ₂ O] grows as a fibrous crystal between wood materials. Since the magnesium compound can be generated even in a relatively small gap between the wood materials, the wood material after the pressure steam curing can be firmly fixed. Moreover, the magnesium compound expands by being carbonated by the reaction with carbon dioxide over time. On the other hand, since cement hydrate shrinks due to the reaction with carbon dioxide over time, the dimensional stability of the wood cement molded body can be excellent by offsetting such expansion and contraction.

Further, the magnesium compound [MgSO ₄ .5Mg (OH) ₂ .3H ₂ O] is non-flammable and imparts flame retardancy to the wood cement molded body, so that the wood cement molded body has excellent flame retardancy. It can be a thing.

  In the curing step, steam curing with water vapor can be performed, for example, under atmospheric pressure before the pressurized steam curing. That is, for example, the molding intermediate can be steam-cured for about 2 hours to 5 days under conditions of 30 to 80 ° C. and a relative humidity of 80% or more.

A wood cement molding can be produced as described above.
In addition, it does not specifically limit as a shape of the obtained wood cement molded object, For example, plate shape, rod shape, and pipe shape are mentioned.
Moreover, a wood cement molded object can be used for uses, such as a housing | casing exterior material, a ceiling, an interior material, a tile, for example.

The wood cement molded body of this embodiment is as illustrated above, but the present invention is not limited to the wood cement molded body illustrated above.
Moreover, the various aspects used in a general wood cement molding can be employ | adopted in the range which does not impair the effect of this invention.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.

  As shown below, a wood cement composition was prepared, and a wood cement molded body (plate-shaped wood cement mortar molded body) was produced using the composition.

Example 1
[material]
Cement: Hayako Portland cement (Sumitomo Osaka Cement Co., Ltd. density 3.13 g / cm ³ ,
Blaine specific surface area 4300 g / cm ³ )
Woody material: wood flour (sawdust from several types of commercially available southern seawood, 5% moisture content by dry mass at 105 ° C,
Grain size-passing through a 2.5mm sieve
Inorganic fiber: Rock wool (density 2.71 g / cm ³ ),
(Fiber length is about 5mm, fiber diameter is about 4μm)
Silicate body: Silica powder (produced in Aichi Prefecture, for autoclave, density 2.54 g / cm ³ ,
Grain size-one that passed through a sieve with an opening of 250 μm)
Slaked lime: JIS R 9001 compliant industrial special slaked lime, calcium hydroxide content 97%,
Particle size-What passed through a sieve with an opening of 250 µm Magnesium sulfate aqueous solution: Recovered from flue gas desulfurization equipment of a small coal-fired thermal power plant
Dilute magnesium sulfate waste liquid with tap water,
Use aqueous solution adjusted to a content of 20% by mass (anhydride conversion) Water: Tap water Magnesium hydroxide: Industrial magnesium hydroxide (containing 98% by mass of magnesium hydroxide,
Grain size-one that passed through a sieve with an opening of 250 μm)

[Kneading process]
In accordance with the composition shown in Table 1, the mixing ratio of magnesium hydroxide (anhydride) to magnesium sulfate (anhydride) is magnesium sulfate: magnesium hydroxide = 1.05: 5 (molar ratio of anhydride). The wood cement composition was mixed with a mortar mixer having a capacity of 10 L in a constant temperature room at 20 ° C. The details of the material charging method and kneading method are as follows.
First, all materials other than the above water and magnesium sulfate aqueous solution are put into a mortar mixer, and the mixer is kneaded for 60 seconds at a low rotation speed (revolution speed 24 rpm, rotation speed 43 rpm). Next, water and magnesium sulfate aqueous solution are mixed. And mixing at a low speed (revolution speed 24 rpm, rotation speed 43 rpm) for 60 seconds, scraping off the wood cement composition, and further increasing the rotation speed of the mixer (revolution speed 37 rpm, rotation speed). (Several 68 rpm) for 120 seconds.
In addition, since the water | moisture content contained in wood flour was as little as 5%, the correction | amendment regarding the water | moisture content derived from wood flour was not performed.

[Molding process]
Kneaded into a forming steel mold (inner dimensions: width 40 mm x length 160 mm x depth 40 mm) with a release vinyl chloride sheet (width 40 mm x length 160 mm x thickness 0.3 mm) 200 g of the wood cement composition was dispensed and placed using a plastic spatula so that the fibers contained in the composition were not oriented, and the wood cement composition was spread as evenly as possible.
A sheet of release vinyl chloride (width 40 mm x length 160 mm x thickness 0.3 mm) is further placed on the leveled wood cement composition, and a molding die (outside dimensions: width 40 mm x length 160 mm x height) 40 mm) was inserted into a steel mold for molding, and then loaded to 200 kN (a load of 31.25 N per mm ² ) using a 2000 kN pressurizer, and the unpressurized state was maintained for 30 seconds and then unloaded.
Similar operations were repeated three times to produce three molded intermediates.

[Curing process]
These molding intermediates were steam-cured for 6 hours under 70 ° C. saturated steam for each mold, then demolded, and then placed in an autoclave and subjected to autoclave curing at 180 ° C. and 10 atm for 18 hours.
As described above, a wood cement molded body (plate-shaped wood cement mortar molded body) was produced.

(Examples 2 to 8)
A wood cement molded body was produced in the same manner as in Example 1 except that the composition was changed to the formulation shown in Table 1.

(Comparative Examples 1-4)
A wood cement molded body was produced in the same manner as in Example 1 except that the composition was changed to the formulation shown in Table 1.

(Comparative Example 5)
It changed into the composition shown in Table 1, and it carried out similarly to Example 1 except having not performed the pressure steam curing (autoclave curing for 18 hours under the conditions of 180 degreeC10 atmospheres) in the curing process, but having performed only the steam curing. A wood cement molding was produced.

(Comparative Example 6)
A wood cement molded body was produced in the same manner as in Example 1 except that the composition was changed to the formulation shown in Table 1.

(Comparative Example 7)
It changed into the composition shown in Table 1, and mixed magnesium sulfate aqueous solution and magnesium hydroxide so that it might become a ratio of 5 mol of magnesium hydroxide (anhydride) to 1.05 mol of magnesium sulfate (anhydride). To form a fibrous magnesium compound [MgSO ₄ .5Mg (OH) ₂ .3H ₂ O] by hydrothermal synthesis at 180 ° C. and 10 atm for 6 hours, and 143 g (about 0.3 mol) of the magnesium compound 1258 g of water was added to the mixture A shown in Comparative Example 7 in Table 1, and the mixing step, the forming step, and the curing step were carried out in the same manner as in Example 1 to produce a wood cement molded body.

<Evaluation test of wood cement molding>
The three wood cement molded bodies of each Example and Comparative Example were subjected to the test and evaluated by their average value. Details of each test item are shown below, and the results are shown in Table 2.
[density]
The mass and dimensions of the wood cement molded body (plate) were measured, and the density was calculated.
[Bending strength]
The bending strength of the wood cement molded body (plate) was evaluated by a three-point bending strength test under the conditions of a span of 100 mm and a loading speed of 10 mm / min.
[Shrinkage (dimensional stability)]
The degree of shrinkage of the wood cement molded body (plate) was measured in accordance with the method defined in Japanese Industrial Standard JIS A 5422 “Ceramic Industry Siding”. That is, the degree of shrinkage after standing for 7 days under conditions of a temperature of 20 ° C. and a relative humidity of 60% (in a constant temperature room) was measured.
[Flame retardance]
The flame retardancy of the wood cement molded body (plate) was measured according to the method prescribed in Japanese Industrial Standard JIS A 1321 “Interior material for building and flame retardancy test method for construction method”.

<Powder X-ray diffraction of wood cement molding>
A sample for powder X-ray diffraction of the wood cement molded body of Example 1 was prepared.
Using a powder X-ray diffractometer (Spectris, instrument name “X'Pert MRD”), measurement was performed under the conditions of an X-ray source CuKα ray, a tube voltage of 45 kV, and a tube current of 40 mA. The diffraction angle was in the range of 2θ = 5.0 to 70.0 °, the scan speed was 4.000 ° / min, and the scan step was 0.020 °. The obtained X-ray diffraction chart is shown in FIG. 1 (upper chart).
In FIG. 1, the lower chart is a chart of a standard substance ([Mg ₆ (OH) ₁₀ · SO ₄ · 3H ₂ O] = [MgSO ₄ · 5Mg (OH) ₂ · 3H ₂ O]). The peak list in the central part is a simplified display of the peak in the chart of the measurement sample by the analysis software of the powder X-ray diffractometer for easy comparison with the peak in the chart of the standard substance.
As can be appreciated from FIG. 1, the generation of the X-ray powder diffraction _{[Mg 6 (OH) 10 ·} SO 4 · 3H 2 O] = [MgSO 4 · 5Mg (OH) 2 · 3H 2 O] was confirmed.

Claims (2)

  A wood cement molded article obtained by molding a wood cement composition containing cement, a wood material, inorganic fibers, magnesium sulfate, magnesium hydroxide, and water and then curing with pressure steam.   The wood cement molded body according to claim 1, wherein the wood cement composition contains the inorganic fiber in an amount of 1 to 2 times that of the wood material.

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