JP3352061B2 - Wood cement board and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood cement board mainly used as an exterior material and a method for producing the wood cement board.

[0002]

BACKGROUND OF THE INVENTION A wood cement board is manufactured by spraying a raw material powder containing cement and a wood reinforcing material such as pulp, wood chip, wood fiber or the like on a board to form a mat, and pressing and curing the mat. However, when used as an exterior material, it is required to have high mechanical strength, durability and frost resistance. In order to satisfy such performance, the wood cement board is required to have a high specific gravity and dense structure.

[0003] However, when the wood cement board has a high specific gravity and dense structure, the weight increases, and in particular, a certain thickness is required for a high-grade exterior material. The problem arises that it becomes difficult.

[0004]

2. Description of the Related Art As a means for solving the above-mentioned problems of the wood cement board, it has been proposed to form a back recess groove which is a hollow (recessed portion) on the back surface of the wood cement board (Japanese Unexamined Patent Publication No. Hei 9 (1999)). -96100).

[0005]

Problems to be Solved by the Invention As shown in FIG. 7, a wood cement board (1) has a densely structured front and back surface layers (2, 3) made of fine raw material powder and a coarse structure core layer made of coarse raw material.
(3) A three-layer structure having the following structure is provided. In such a three-layer wood cement board (1), since the front and back layers (2, 3) have a dense structure, the surface is smooth and the mechanical strength is large, and the durability and frost resistance are high. Assured, the core layer (4) has a coarse structure, so that it is lightweight and the core layer (4)
Due to the cushioning property and the dense smoothness of the surface layer (2), a clear uneven pattern can be formed on the surface of the wood cement board (1).

The wood cement board (1) having the three-layer structure is formed by dispersing fine raw material powder on a template to form a surface mat, and then dispersing coarse raw material thereon to form a core layer mat. It is manufactured by spraying fine raw material powder on the top to form a back layer mat, and pressing and curing such a three-layer structure mat.The wood cement board (1) )), The back (upper surface) of the three-layered mat is hollowed out and then pressed and cured.

[0007] Such wood cement board obtained by the process (1), the core layer of the coarse structure at the point of the recess (5) as shown in FIG. 8 (4) will be exposed, the resulting Exposed part
Therefore, there is a problem that water easily penetrates into the inside of the plate , and particularly, the frost resistance is greatly reduced.

[0008]

Means for Solving the Problems As a means for solving the above-mentioned conventional problems, the present invention provides a wood cement board (1) having a concave portion (5) on the back surface, wherein the wood cement board (1)
Is a surface layer (2), and a recess (5A) is formed at a predetermined position from the back side.
Back surface of the core layer (4), and the core layer (4) having the concave portion (5A).
Three-layer structure consisting of a back layer (3) coated and formed along
The surface layer (2) and the back layer (3) are fine raw material powders.
The core layer (4) is composed of a coarse raw material powder.
Der which provides wood cement plate (1) having a rough structure made is, with the concave and convex pattern on the surface of the wood cement plate (1)
It is desirable to have been. Further, in the present invention, the fine raw material powder is sprayed on the plate (6) to form the surface mat (2A), and the coarse raw material is sprayed on the surface mat (2A) and a predetermined portion is formed from the rear surface side.
Recess by spraying a fine fine raw material powder onto the back surface of the recess to form a core layer mat was formed (5A) (4A), said core layer mat (4A) to (5
A) A back layer mat (3
A), and an upper mold plate on which a convex portion (7A) corresponding to a concave portion (5) forming portion is formed from the multilayer mat thus formed.
(7) A method for producing a wood cement board (1) which is pressed and cured. The core layer mat (4A) the back surface of the recess (5
A) is Shinso mat (4A) after forming, or the core layer mat is formed by hollowing out a predetermined portion from the rear surface side (4A) back surface of the recessed portion (5A) of the core of the core layer mat (4A) When forming the layer mat (4A), it is desirable that the layer mat (4A) is formed by reducing the amount of scattered raw material at a predetermined location. The mat M is clamped by the lower mold plate 6 and the upper mold plate 7 in the pressing step, and the lower mold plate 6 has an irregular pattern E 'formed thereon. Is desirable.

[0009]

The wood cement board (1) of the present invention has a recess on the back.
Because of the presence of (5), even if the structure of the wood cement board (1) is made dense and high in specific gravity, it becomes lighter by the concave portion (5). Since the back surface including the concave portion (5) is coated with the back surface layer (3) having a dense structure made of fine raw material powder, the water absorption of the wood cement board (1) is suppressed. And high mechanical strength, durability and frost resistance are guaranteed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The main components of the wood cement board of the present invention are cements and wood reinforcing materials. The cements include, for example, Portland cement, blast furnace slag cement, silica cement, fly ash cement,
Alumina cement and the like, and the wood reinforcing material is, for example, wood chips, wood fiber bundles, wood wool, wood flour, wood pulp and the like.

[0011] In addition to the above main components, raw materials of the wood cement board of the present invention include silica-containing substances such as silica sand, silica stone powder, silica fume, blast furnace slag, fly ash, shirasu balloon, perlite, bentonite, and diatomaceous earth. , Calcium chloride, magnesium chloride, iron chloride, aluminum chloride, sodium chloride, potassium chloride, lithium chloride, etc.
Sulfate anhydrides such as aluminum sulfate, alum, iron sulfate, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate and the like, or those having water of crystallization, nitrates such as calcium nitrate and calcium nitrite, and anhydrides or crystals of nitrite Incorporation of water-containing substances, formate such as calcium formate and calcium acetate, metal salts of organic acids such as acetate, cement coagulants such as sodium aluminate and water glass, and water repellents such as wax, paraffin and silicone Agents and expandable thermoplastic plastic beads such as expandable polystyrene beads may be used.

The wood cement board of the present invention has a three-layer structure. In this case, use fine raw material powder for the front and back layers,
The raw material used for the core layer may partially contain powder such as wood flour.

[0013] The fine raw material powder used for the front and back layers is mixed with the above cements and wood chips and / or wood flour as a wood reinforcing material. Usually, the above-mentioned silicic acid-containing substance and, if desired, an inorganic filler, a curing accelerator, a water repellent and the like are mixed. The mixing ratio of the above raw materials is 30:70 to 70:30 by weight for the cement: silicic acid-containing substance, and the wood reinforcing material is 5 to 30% by weight, more preferably 5 to 30% by weight based on the total amount of the fine raw material powder. 20% by weight.

The crude material used for the core layer is mixed with the above cements, and as a wood reinforcing material, wood fiber bundles, wood chips, and the like. Usually, the above-mentioned silicic acid-containing substance and, if desired, an inorganic filler, a curing accelerator, a water repellent, foamable thermoplastic plastic beads, and the like are mixed. The mixing ratio of the above raw materials is 70:30 to 30:30 for cements and silicic acid-containing substances.
The weight ratio of the wood reinforcing material is 5 to 35% by weight, more preferably 7 to 25% by weight, based on the total amount of the raw material.

In order to manufacture the wood cement board (1) of the present invention, as shown in FIG. 1, for example, the fine raw material powder is spread on a template (6) having a concave and convex pattern E ′ on the mold surface. The surface layer mat (2A) is formed, and the raw material is further dispersed thereon to form the core layer mat (4A). The thickness of the surface mat (2A) is usually 10 mm to 25 mm, and the thickness of the core mat (4A) is usually 25 mm.
~ 70 mm. Then recess hollowed a top predetermined portion from the rear surface side of the core layer mat (4A) As shown in FIG. 2 (5A)
To form Then, as shown in FIG. 3, the fine raw material powder is sprayed from above, and the back layer mat including the concave portion (5A) is sprinkled.
(3A) is formed. The thickness of the back layer mat (3A) is usually 10 mm
Preferably, the back layer mat (3A) is slightly thinner than the surface layer mat (2A) from the viewpoint of the durability of the wood cement board. After forming the back layer mat (3A) as described above, the upper mold plate (7) is placed thereon from above as shown in FIG. 4 and pressed usually at a pressure of 10 kg / cm ^{2 to} 50 kg / cm ² . At a predetermined position on the mold surface of the upper mold plate (7), a concave portion of the product is provided.
A projection (7A) corresponding to (5) is formed.

While maintaining the pressed state, the mat M having the three-layer structure is subjected to primary curing at a temperature of 40 to 80 ° C. for usually 6 to 20 hours, and then at a temperature of 120 to 180 ° C. and a relative humidity of 90 to 100%. The secondary curing is performed by autoclave curing or normal temperature curing for 5 to 20 hours, the mat M hardens during the curing, and after curing, the mat M is removed from the mold to obtain the mold shown in FIGS.
Wood cement board with concave part (5) formed on the back as shown in
(1) is manufactured. Since the wood cement board (1) is reduced in weight by the concave portion (5), and the front and back surfaces are covered by the front and back layers (2, 3) having a dense structure including the concave portion (5) on the back surface, High strength and good durability and frost resistance are provided.

Except for the present embodiment, in order to form the concave portion (5A) on the back surface of the core layer mat (4A), for example, when forming the core layer mat (4A) by distributing a crude material, the concave portion (5A) is formed. A sieve plate with a blind plate attached to the scheduled portion may be interposed to reduce the amount of sparse raw material spread at that portion.

[0018]

Effect of the Invention In the wood cement board of the present invention, a concave portion is formed on the back surface and further covered with the back surface layer having a dense structure including the concave portion, so that it is lightweight, high strength and good water absorption and durability. A wood cement board suitable for an exterior material having good frost resistance and good board handling properties can be obtained. Therefore, the concave portion on the back surface can be set large, so that effective weight reduction can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 6 show one embodiment of the present invention.

FIG. 1 is a partial side sectional view showing a state where a surface layer and a core layer are formed.

FIG. 2 is a partial cross-sectional side view of a core layer in a state where concave portions are formed.

FIG. 3 is a partial side sectional view showing a state where a back surface layer is formed.

FIG. 4 is a partial sectional side view of a pressed state.

FIG. 5 is a back perspective view of the manufactured wood cement board.

FIG. 6 is a sectional view taken along the line AA in FIG. 5, and FIGS. 7 and 8 show a conventional example.

FIG. 7 is a partial side sectional view of a three-layer structure.

FIG. 8 is a partial side sectional view showing a state in which a concave portion is formed.

[Explanation of symbols]

1 Wood cement board 2 Surface layer 2A Surface mat 3 Back layer 3A Back layer mat 4 Core layer 4A Core layer mat 5 Concave 5A Core layer recess 6 Lower mold board (board) 7 Upper mold board 7A Convex part E 'Irregular shade Pattern M mat

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ identification code FI C04B 18/26 C04B 18/26 // C04B 111: 40 111: 40 (58) Field surveyed (Int.Cl. ⁷ , DB name ) C04B 18/26 C04B 18/24 C04B 16/02

Claims (6)

(57) [Claims] 1. A wood cement board having a concave portion on a back surface, wherein said wood cement board is located at a predetermined position from a surface layer and a back side.
A core layer having a concave portion, and a back surface of the core layer having the concave portion
A three-layer structure consisting of a back layer coated along
Yes, and dense that a fine material powder with the surface layer and the backing layer
Structure, and the core layer has a coarse structure composed of coarse raw material powder.
Wood cement board, wherein the Turkey 2. The wood cement board has an uneven pattern on its surface.
2. The wood cement board according to claim 1, wherein 3. Surface mat by spraying fine raw material powder on a plate
Is formed, and the raw material is sprayed on the surface mat to remove
Forming a core layer matte formed recesses in Luo predetermined positions, said core
A fine raw material powder is sprayed on the back surface of the layer mat to form the concave portion.
The backing layer mat along the rear surface of the core layer mat you formed, this
From the top of the multilayer mat formed as described above,
Pressing and curing the upper template with the corresponding projections
PROCESS FOR PRODUCING WOOD CEMENT BOARD FEATURES 4. The core layer mat has a concave portion on the back surface of the core layer mat.
Narugo, this hollowing out a predetermined portion of the core layer mat from the back side
The production of a wood cement board according to claim 3 formed by:
Method 5. The rear surface of the recess of the core layer mat core layer mat
When forming , reduce the amount of coarse raw material
Method for producing a wood cement board according to claim 3 thus formed 6. The lower surface of the mat in the pressing step.
It is clamped by the template and the upper template, and the lower template is
The wood cement board according to claim 3 , wherein the uneven pattern is formed.
Manufacturing method