JP4163366B2 - Wood cement board and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wood cement board suitable for a building board such as an outer wall material and a manufacturing method thereof.
[0002]
[Prior art]
Conventionally, structural plywood has been used as a building material, particularly as a building surface material, but a substitute for wood resource depletion is required. At present, oriented strand boards (OSB) and medium density fiber boards (MDF) that can use waste materials are provided as alternatives. Further, a wood cement board manufactured by a dry method or a semi-dry method using a cement-based inorganic material and a wood material as raw materials is provided. Such a wood cement board is excellent in terms of formability, workability, durability, fire resistance and the like, and is extremely useful as an outer wall material of a building.
[0003]
[Problems to be solved by the invention]
However, OSB and MDF are not necessarily sufficient in terms of performance such as water resistance, durability and fire resistance, while wooden cement boards are inferior to plywood, OSB, MDF and other wooden building boards in terms of strength. There is a problem.
[0004]
Therefore, the subject of this invention is providing the wood cement board which has the intensity | strength equivalent to a wood type building board.
[0005]
[Means for Solving the Problems]
As a means for solving the above conventional problems, the present invention has a three-layer structure, and the front and back layers contain a wafer and flakes in a weight ratio of 10: 0 to 8: 2 as a hydraulic inorganic material and a wood material. It is a hardened layer, and the core layer is a hardened layer containing a hydraulic inorganic material and a wafer and flakes in a weight ratio of 0:10 to 4: 6, and a hydraulic inorganic material and a wafer and flakes on the board. Is sprayed on the raw material mixture for the surface layer containing 10: 0 to 8: 2 by weight, and 0:10 to 4: 6 weight of the hydraulic inorganic material and the wafer and the flakes are placed on the raw material mixture for the surface layer. The raw material mixture for the core layer contained in a ratio is sprayed, the raw material mixture for the back layer similar to the raw material mixture for the surface layer is sprayed to form a three-layer mat, and the mat is pressed in the presence of moisture. Tighten to primary cure, the primary There is provided a method of manufacturing a wood cement board to ambient temperature curing or autoclave curing the embodying.
[0006]
In the above-mentioned wood cement board, the core layer using wafers and flakes in the range of 0:10 to 4: 6 weight ratio as the wood material is flake-rich and becomes dense and shows high strength against compressive stress. On the other hand, the front and back layers using wafers and flakes in the range of 10: 0 to 8: 2 weight ratio as a wood material are wafer rich, so the adhesion area between the wafers is large, and the front and back layers are resistant to tensile stress. Therefore, the wood cement board has a high bending strength. Therefore, the wood cement board of the present invention expresses sufficient strength.
[0007]
The hydraulic inorganic material / wood material weight ratio is preferably 2.5 to 3.5 for the front and back layers and 1.5 to 3.0 for the core layer, and the wafer used for the wood cement board is The strand is preferably oriented so that the front and back layers and the core layer of the wood cement board are substantially orthogonal to each other. Further, as the flakes, it is preferable to use waste flakes separated from the waste wood and / or scraps of wood chip cement boards or waste flakes generated from the wood chip cement board manufacturing process.
[0008]
The wood cement board is sprayed with a raw material mixture for a surface layer containing a hydraulic inorganic material and wafers and flakes in a ratio of 10: 0 to 8: 2 on the board, and on the raw material mixture for the surface layer, Scatter the raw material mixture for the core layer containing the hydraulic inorganic material and the wafer and flakes in a weight ratio of 0:10 to 4: 6, and spray the same raw material mixture for the back layer as the raw material mixture for the surface layer. The mat can be produced by forming a mat having a three-layer structure, pressing the mat in the presence of moisture to perform primary curing, and curing the primary cured body at room temperature or autoclave. At this time, it is preferable to use strands as the wafer, and to disperse the strands so that the front and back layers and the core layer of the wood cement board are substantially orthogonal to each other.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The wood cement board of the present invention is mainly made of a hydraulic inorganic material and a wood material.
[0010]
[Hydraulic inorganic material]
Examples of the hydraulic inorganic material used in the present invention include Portland cement, blast furnace cement, silica cement, fly ash cement, alumina cement and other cements, silica powder, silica sand, quartzite powder, water glass, silica fume, FA balloon, A mixture of siliceous balloons, perlite, mica, diatomaceous earth, dolomite and other silicic acid-containing substances and the above cements; Examples thereof include a mixture with a silicic acid-containing substance.
Among the cement-based inorganic materials, a mixture of cements and silicic acid-containing substances is preferable, and a mixing ratio (weight ratio) of cements and silicic acid-containing substances is preferably 1: 2 to 6: 1.
[0011]
The flakes used in the wood cement board of [woody material The present invention, thickness 1mm or less, a length of 2 to 10 mm. The flakes are preferably waste flakes obtained by pulverizing and separating waste wood and scraps of wood cement boards or waste flakes produced during production of wood cement boards.
[0012]
As the wafer used in the wood cement board of the present invention, a strand is preferably used. A wafer is a relatively large piece manufactured by cutting wood, and a strand is a strip having directionality among the wafers, and the grain is formed along the longitudinal direction. ing.
[0013]
The dimensions of the wafer, the length 30～220Mm, width 10 to 100 mm, Ri der range of thickness 0.1 to 1.5 mm, as the wafer is not a strand length 40 to 100 mm, a width 40~90mm using those relatively long and shape and are close range, in the case of strands, the length 30～220Mm, Ru der within the width 10 to 70 mm.
[0014]
Moreover, it is preferable that the wafer has been subjected to a heat consolidation treatment. By performing this heat-consolidation treatment, the wafer becomes easy to conform to the plate, and a wood cement plate having a uniform thickness and excellent dimensional stability can be obtained. The heat consolidation treatment is usually performed at about 180 ° C. for about 5 minutes.
[0015]
As described above, when wafers are used for the wood cement board, especially the front and back layers, the wafers, which are relatively large pieces, have high strength against tensile stress because the bonding area increases when they overlap each other. In addition, the amount of cementitious inorganic material used can be reduced. In particular, when a strand is used as the wafer and a strand is also used as the core layer, it is desirable to orient the strand so that the front and back layers and the core layer of the wood cement board are substantially orthogonal to each other. In this case, due to the high tensile strength in the grain direction of the strand itself, the strength against the tensile stress in both the longitudinal direction and the short direction of the wood cement board becomes extremely high. Usually, in the front and back layers of the wood cement board, the strands are oriented in the longitudinal direction, and in the core layer, the strands are oriented in the lateral direction.
[0016]
[Other ingredients]
In the wood cement board of the present invention, as components other than the cement-based inorganic material and wood material, magnesium chloride, magnesium sulfate, calcium chloride, calcium sulfate, sodium aluminate, potassium aluminate, aluminum sulfate, water glass, calcium formate A hardening accelerator such as vermiculite and bentonite, a water repellent such as wax, paraffin and silicon, a reinforcing material such as a synthetic resin emulsion, an expandable thermoplastic bead, and a plastic foam may be added. . In addition, these illustrations do not limit the present invention.
[0017]
[Composition of wood cement board] The raw material mixture for the front and back layers in the wood cement board of the present invention comprises 30-60% by weight of cement as a hydraulic inorganic material, 10-60% by weight of a silicic acid-containing substance, and a wafer as a wood material. the flakes 10: 0-8: use 2 weight ratio, the weight ratio of the hydraulic inorganic material / wood material and 2.5 to 3.5, the raw material mixture for the core layer, as the hydraulic inorganic material 30 to 60% by weight of cement, 10 to 60% by weight of silicic acid-containing substance, and 0 to 10 to 4: 6 by weight of wafer and flake as wood material, and the weight ratio of the above hydraulic inorganic material / wood material is shall be the 1.5 to 3.0. In order to accelerate the curing of the raw material mixture in the production process, it is preferable to use pearlite as a part of the silicic acid-containing substance. In this case, the pearlite is preferably added in an amount of 15% by weight or less in the raw material mixture. Furthermore, if a hollow lightweight body such as pearlite, FA balloon, shirasu balloon or the like is used as the silicic acid-containing material for the core layer, the wood cement will be used even if the front and back layers are made dense by increasing the pressing pressure in the production of the wood cement board described later. The weight of the board does not increase.
[0018]
[Manufacture of wood cement board]
The wood cement board of the present invention is preferably produced by a so-called dry method or semi-dry method.
As a preferable example of the production method in the present invention, first, a raw material mixture for the surface layer is first sprayed on a plate (conveying plate, substrate, etc.), then, the raw material mixture for the core layer is sprayed thereon, and further Then, a back layer raw material mixture similar to the surface layer raw material mixture is sprayed to form a three-layer mat.
[0019]
When using the strand as a wafer of said surface backing layer material mixture, the strands are those length 50 to 80 mm, width 10 to 20 mm, a thickness of less than 0.3 mm, the wood cement the strands to produce It is preferable to orient in a predetermined direction (for example, the longitudinal direction) of the plate. Furthermore, when using a strand also for this raw material mixture for core layers, this strand is smaller than the strand for front and back layers, 30-50 mm in length, about 10 mm in width, and thickness is thicker than the thing for front and back layers. and 0.3 to 0.5 mm, the strands preferably be oriented such that the strands substantially perpendicular to said surface backing layer (e.g. the lateral direction). The strands may be oriented by a conventional method, for example, using a forming machine in which a disk-type spraying head is rotating or a sieve in which a plurality of slits are arranged in parallel.
[0020]
In the case of the semi-dry method, water is added to the raw material mixture so that the water content is 15 to 50% by weight, and then the raw material mixture is sprayed. In the case of the dry method, the formed mat Water is added so that the water content is 15 to 50% by weight.
[0021]
Thus, the flakes in the raw material mixture for the core layer dispersed between the raw material mixture for the front and back layers are rich, and enter the gaps between the wafers in the raw material mixture for the front and back layers of the wafer. Thus, the flakes of the core layer that have entered the gap between the wafers of the front and back layers exhibit a so-called anchoring effect and improve the strength of the front and back layers.
[0022]
After the three-layer structure mat is formed as described above, a mold plate having a smooth mold surface or a mold plate having an uneven pattern on the mold surface is placed on the surface of the mat and pressed together with the mat. First cure under heating. The temperature applied in the primary curing is usually 50 to 100 ° C., and the pressing pressure is usually 2 to 5 MPa. As described above, when a hollow lightweight body is used for the core layer, the front and back layers can be densified by increasing the pressing pressure.
After the primary curing, the obtained primary cured body is demolded and then subjected to normal temperature curing or autoclave curing. The normal temperature curing is usually performed at normal temperature for 2 to 5 days, and the autoclave curing is normally performed at a humidity of 85% RH or higher and a temperature of 150 to 180 ° C. for 10 to 18 hours. After normal temperature curing or autoclave curing, a surface treatment is performed through a drying process to obtain a product.
[0023]
In the wood cement board, the weight ratio of the surface layer, the core layer, and the back layer is preferably 1: 2: 1 to 1: 5: 1, and more preferably about 1: 3: 1. The thickness of the wood cement board is usually 12 to 18 mm and the specific gravity is about 1.
[0024]
The core layer of the wood cement board produced as described above is flake-rich, and even when using strands, the core layer structure is denser because it is smaller and thicker than the front and back layer strands. Therefore, the thickness change due to water absorption and moisture absorption is suppressed, and high strength against compressive stress is exhibited. On the other hand, the front and back layers of the wood cement board use a wafer, which is a relatively large piece of wood, as a wood material, and the wafers have a large overlapping adhesion area, so that they exhibit high strength against tensile stress. As a result, the wood cement board has a high bending strength with respect to an external force from the surface.
[0025]
[Examples 1 , 2 , 6 to 11, Reference Examples 1 to 3, Comparative Examples 1 to 3] Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention is limited to these examples. Is not to be done.
[0026]
[Table 1]
[0027]
After adding water to each raw material mixture shown in Table 1 so that the water content is 45% by weight, the raw material mixture for the surface layer is sprayed on the transport plate, and the raw material mixture for the core layer is sprayed thereon Furthermore, a back layer raw material mixture (same as the surface layer raw material mixture) was sprayed thereon to form a three-layer mat. The raw material mixture for the front and back layers was dispersed so that the strands in the raw material mixture were oriented along the longitudinal direction of the wood cement board. When strands were also used for the core layer, the strands were oriented and scattered along the short direction of the wood cement board.
[0028]
Each of the three-layer mats obtained as described above was press-clamped at a surface pressure of 2 MPa and heated at 70 ° C. for 10 hours for primary curing. Next, the pressed state was released, and the laminate was cured in an autoclave at 165 ° C. for 7 hours at a vapor pressure of 6 kgf / cm ² , and a three-layered wood cement board was obtained through a drying process.
[0029]
About each obtained wood cement board, bending strength (based on JISA1409), specific gravity, board thickness, and thickness swelling rate were measured. The results are shown in Table 2.
[0030]
[Table 2]
[0031]
In Table 2, Comparative Examples 1 and 2 do not use strands for the front and back layers and the core layer, and Comparative Example 3 uses strands only for the core layer.
Table 2 shows that all of the examples using strands for the front and back layers have good bending strength, but Comparative Examples 1 and 2, which do not use strands for the front and back layers and the core layer, are inferior to the examples in bending strength. Even in Comparative Example 3 where strands are used only for the layers, the bending strength is much lower than in the corresponding Examples 6 to 11.
[0032]
【The invention's effect】
According to the present invention, there is provided a wood cement board having a strength comparable to that of a wood-based building board and having water resistance, durability and fire resistance equivalent to those of a general wood cement board.

Claims (4)

It has a three-layer structure consisting of a surface layer, a core layer, and a back layer ,
The front and back layers as hydraulic inorganic material, containing 10 to 60 wt% cements 30-60 wt% and siliceous material, and, as a wood material, length 50 to 80 mm, width 10-20 mm, or less thickness 0.3 mm, a strip-shaped strands grain is formed along the longitudinal direction, 1 mm or less in thickness, length 2 to 10 mm and a flake 10: 0-8: containing 2 weight ratio, the weight ratio of the water hydraulic inorganic material / the wooden material is a cured layer of 2.5 to 3.5,
The core layer is, as a hydraulic inorganic material, containing the cements 30-60 wt% and 10-60 wt% silica-containing material, and, as a wood material, length 30 to 50 mm, width of about 10 mm A strip of strands having a thickness of 0.3 to 0.5 mm and having a grain formed along the longitudinal direction, a strip-like strand having a smaller size and a larger thickness than the front and back layer strands, and a thickness of 1 mm or less, the length 2 to 10 mm of the flakes 0: 10 to 4: containing 6 weight ratio of a flake richer than the hardened layer of said surface lining, of the water hydraulic inorganic material / the wooden material A wood cement board characterized by being a hardened layer having a weight ratio of 1.5 to 3.0 . The strands of the front and back layer of strands and the core layer, wood cement board according to claim 1, characterized in that it is oriented substantially orthogonally. On a plate, as the hydraulic inorganic material, containing 10 to 60 wt% cements 30-60 wt% and siliceous material, and, as a wood material, length 50 to 80 mm, width 10 to 20 mm A strip-shaped strand having a thickness of 0.3 mm or less and a grain of which is formed along the longitudinal direction, and a flake having a thickness of 1 mm or less and a length of 2 to 10 mm are 10: 0 to 8: 2. And a raw material mixture for the surface layer in which the weight ratio of the hydraulic inorganic material / woody material is 2.5 to 3.5 ,
On the spread raw material mixture for the surface layer , 30 to 60% by weight of cement and 10 to 60% by weight of a silicic acid-containing substance are contained as a hydraulic inorganic material , and a length of 30 as a woody material. A strip having a thickness of about 50 mm , a width of about 10 mm , a thickness of 0.3 to 0.5 mm , and a grain that is formed along the longitudinal direction. The strip is smaller and longer than the surface strand. A strand having a shape of 1 mm and a flake having a thickness of 1 mm or less and a length of 2 to 10 mm in a weight ratio of 0:10 to 4: 6 , flake richer than the raw material mixture for the surface layer, A raw material mixture for a core layer having a hard inorganic material / woody material weight ratio of 1.5 to 3.0 is sprayed,
Furthermore, a raw material mixture for the raw material mixture similar to the backing layer for the surface layer, and forming a mat sprayed with three-layer structure on top of the sprayed raw material mixture for core layer,
The mat is pressed in the presence of moisture to be primarily cured,
A method for producing a wood cement board, characterized in that the primary cured body is cured at room temperature for 2 to 5 days at room temperature , or is autoclaved at a humidity of 85% RH or higher and a temperature of 150 to 180 ° C. for 10 to 18 hours. . The strands of the front and back layer of strands and the core layer, the manufacturing method of the wood cement board according to claim 3, characterized in that the cloth distributed substantially orthogonally.