JP4080674B2 - Wood chip cement board manufacturing method - Google Patents

Description

【００２１】
〔比較例１〜３〕
実施例と同様ににして表１に示す配合条件で成形材料を調製し、該成材料を基板上に散布し、マットをフォーミングし、該マットを圧締して一次硬化せしめ、次いでオートクレーブ養生を行なって比較試料を作製した。ただし比較例１の場合、セメントと人造繊維とをプレミックスしたうえで成形材料を調製し、養生硬化せしめて試料を作製したものであるが、比較例２の場合は人造繊維を全く添加せず、また比較例３の場合は人造繊維をセメントにプレミックスせず、木片、その他成分と一緒に添加混合して成形し、養生硬化せしめて比較試料を作製した。得られた各試料の物性試験のデータを表１に示す。
【００２２】
表１によれば、ポリプロピレン繊維を５重量％含む成形材料を使用した比較例１は人造繊維が糸まり状になって板に均一に分散しないので、クラック発生を完全に防止することは出来ず撓み性も良くない。また人造繊維を添加しない比較例２もクラック発生を完全に防止出来ず、また撓み性も良くない。更にセメントと人造繊維とをプレミックスしない比較例３もクラック発生を完全に防止出来ず、撓み性も良くない。一方本発明の各実施例ではクラック発生が完全に防止されかつ撓み性も良い。
【００２３】
【発明の効果】
本発明ではセメント系無機材料と人造繊維とをプレミックスしてから木片を混合するから、セメント系無機材料と人造繊維とを木片に干渉されることなく均一に混合することが出来、その結果得られた木片セメント板のセメント硬化体中には均一に人造繊維が分散しており、クラック発生を効果的に防止出来る。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wood chip cement board suitable for a building board such as an outer wall material.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, there has been provided a wood chip cement board produced by spraying a molding material containing a cement-based inorganic material and wood chips on a substrate as a building material, forming the mat, and curing the mat by pressing and curing. ing. Such wood-cement cement boards are excellent in terms of formability, workability, durability, fire resistance, and the like, and are extremely useful as building materials such as wall boards and roof baseboards.
[0003]
However, the occurrence of fine cracks is a problem in the above-mentioned wood piece cement board. There are three possible patterns for this crack in the hardened cement body, in the wood piece, and in the boundary between the hardened cement body and the wood piece, but the main one is a crack in the hardened cement body. .
[0004]
Conventionally, artificial fibers have been added to prevent cracks, but when preparing molding materials by mixing cement, wood pieces and artificial fibers, the bulk of the wood pieces is so large that the fibers are entangled with the wood pieces and cemented. And the fibers are not uniformly mixed, and there is a problem that the reinforcing effect does not increase so much.
[0005]
[Means for Solving the Problems]
As a means for solving the above-mentioned conventional problems, the present invention premixes cement-based inorganic materials and man-made fibers, and then forms a mat by spraying a molding material mixed with wood pieces on a substrate. The present invention provides a method for producing a wood chip cement board, which is first hardened by pressing in the presence of moisture, and the primary hardened body is cured at room temperature or autoclave. The artificial fiber is preferably contained in the molding material in the range of 0.25 to 4% by weight.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The wood piece cement board of the present invention is mainly made of a cement-based inorganic material, wood pieces and artificial fibers.
[0007]
[Cement-based inorganic materials]
The cement-based inorganic material used in the present invention is a hydraulic inorganic material mainly composed of calcium silicate. Examples of such an inorganic material include Portland cement, or a blast furnace in which Portland cement is mixed with blast furnace slag. Examples include cement, fly ash cement mixed with fly ash, silica cement mixed with silica materials such as volcanic ash and white clay, alumina cement, and blast furnace slag.
[0008]
[Wood pieces]
The wood piece used in the present invention is not particularly limited, but for a single layer, an average length of 1 to 20 mm and a thickness of 0.5 to 3 mm are preferable, and a surface layer in a two-layer structure or a three-layer structure. For the front and back layers, those having an average length of 1 to 12 mm and a thickness of 0.5 to 1.5 mm (fine-grained wood pieces) are preferred, and for the back layer in a two-layer structure, the average length is 1 to 15 mm. Those having a thickness of 0.5 to 2 mm (medium grain pieces) are preferred, and those having an average length of 5 to 20 mm and a thickness of 0.8 to 2.5 mm (coarse grains) for a core layer in a three-layer structure Wood pieces) are preferred.
As described above, the wood piece for the back layer in the two-layer structure may be slightly rougher than the wood piece for the surface layer, but the finer one is less likely to cause cracks.
[0009]
[Artificial fiber]
As artificial fibers used in the present invention, recycled fibers such as viscose rayon and cupra; semi-synthetic fibers such as acetate, triacetate and promix; polyamide fibers such as nylon and aramid; polyester fibers such as polyethylene terephthalate and polyarylate; Acrylic fibers, polyolefin fibers such as polyethylene and polypropylene, polyvinyl alcohol fibers (vinylon), polyvinyl chloride fibers such as polyvinyl chloride and polyvinylidene chloride, polyurethane fibers, polyoxymethylene fibers, polytetrafluoroethylene fibers, benzoate fibers, Synthetic fibers such as polyimide fibers; inorganic fibers such as glass fibers, carbon fibers, alumina fibers, silicon carbide fibers, boron fibers, lock fibers, rock wool, slag fibers; iron, stainless steel Steel, aluminum, and metal fibers such as copper and the like, can be used as a mixture one or two or more thereof.
[0010]
Pulp is also used as a reinforcing fiber for this type of cement board, but because pulp contains a cement hardening inhibitor, the hardening of the cement may be incomplete during the curing and curing process of the board, and the strength of the product may not increase. . Therefore, it is necessary to add a large amount of cement hardening accelerator, but in this case, the raw material cost becomes high. However, in the present invention, since artificial fibers not containing a cement hardening inhibitor are used, problems such as the case of using the above pulp are eliminated.
[0011]
Among the above-mentioned artificial fibers, it is preferable to use nylon fiber or vinylon from the viewpoint of adhesion to a hydraulic cement-based inorganic material, and polypropylene fiber or polyester fiber from the viewpoint of impact resistance. In order to impart a certain degree of orientation to the artificial fiber, the fiber length of the artificial fiber is preferably 5 to 20 mm. If the fiber length is less than 5 mm, the strength or toughness of the wood piece cement board cannot be sufficiently improved, and if the fiber length exceeds 20 mm, the fiber may be in a string shape. In addition, you may use the artificial fiber which has several different fiber length.
[0012]
[Other ingredients]
In the wood chip cement board of the present invention, magnesium chloride, magnesium sulfate, calcium chloride, calcium sulfate, sodium aluminate, potassium aluminate, aluminum sulfate, calcium formate, as components other than the cement-based inorganic material, wood pieces and artificial fibers, Addition of hardening accelerators such as water glass, mineral powders such as vermiculite and bentonite, water repellents such as wax, paraffin and silicon, reinforcing materials such as synthetic resin emulsions, expandable thermoplastic beads and plastic foam Also good.
The above examples are not intended to limit the present invention.
[0013]
[Composition of wood chip cement board]
In the raw material mixture of the wood chip cement board of the present invention, the cement-based inorganic material is preferably 50 to 80% by weight, the wood piece is preferably 20 to 50% by weight, and the artificial fiber is 0.25 to 25% by weight. It is preferably 4% by weight.
In the raw material mixture, if the mixing ratio of the wood pieces is less than 20% by weight, the reinforcing effect by the wood pieces is not sufficient, and if the mixing ratio of the wood pieces exceeds 50% by weight, the consolidation of the cement-based inorganic material is inhibited and the strength is rather increased. It tends to decrease. In addition, if the mixing ratio of the artificial fibers is less than 0.25% by weight, the generation of cracks cannot be sufficiently prevented or suppressed, and if the mixing ratio of the artificial fibers exceeds 4% by weight, the artificial fibers become thread-like. It becomes difficult to uniformly disperse the molding material.
[0014]
[Manufacture of wood chip cement board]
The wood chip cement board of the present invention is produced by a so-called dry method or semi-dry method.
In the case of the dry method, first, the cement-based inorganic material and the artificial fiber are premixed. In this way, the artificial fiber can be uniformly mixed with the cement-based inorganic material without being interfered with by the wood pieces. Next, a wood piece and, if necessary, an aggregate and a third component are added and mixed to prepare a molding material. The molding material is spread on the substrate to form the mat, and water is added to the mat so that the water content is 15 to 50% by weight.
[0015]
On the other hand, in the case of the semi-dry method, first, the cement-based inorganic material and the artificial fiber are premixed, water is added to the premixed product, and then a piece of wood containing the piece of wood and, optionally, an aggregate and a third component A molding material is prepared by adding water to the mixture and mixing it with the premix. The moisture content of the molding material is set to 15 to 50% by weight. In this case, it is desirable that the amount of water added to the premixed product and the amount of water added to the wood pieces be in a ratio of about 2: 8 to 4: 6. The molding material thus obtained is dispersed on the substrate to form the mat.
[0016]
When the mat is formed as described above, the mat is pressed together with the substrate to be primarily cured 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.
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 14 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.
[0017]
When a concavo-convex pattern is provided on the surface of the wood chip cement board, a concavo-convex pattern corresponding to the concavo-convex pattern may be formed on the mold surface of the substrate. Moreover, when manufacturing a smooth wood piece cement board without an uneven | corrugated pattern on the surface, you may use a conveyance board directly as a board | substrate.
[0018]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention is not limited to these examples.
[0019]
[Examples 1-3]
The sample of the example was premixed with cement and man-made fiber (polypropylene fiber) under the compounding conditions shown in Table 1 as a molding material, followed by wood chips, hardener (water glass) and waterproofing agent (calcium stearate) as other components. The molding materials of Examples 1 to 3 were prepared by adding and mixing, and further adding and mixing moisture. The molding material is spread on the substrate to form the mat, and the mat is primarily cured under the conditions of the mat temperature of 80 ° C. and the pressing pressure of 3.5 MPa, and then the autoclave curing is performed for 7 hours while maintaining the humidity of 90 RH and the temperature of 165 ° C. The samples of Examples 1 to 3 were manufactured under the conditions described above.
[0020]
[Table 1]

[0021]
[Comparative Examples 1-3]
In the same manner as in the examples, a molding material was prepared under the blending conditions shown in Table 1, the component material was spread on the substrate, the mat was formed, the mat was pressed and primary cured, and then the autoclave curing was performed. A comparative sample was prepared. However, in the case of Comparative Example 1, a molding material was prepared after premixing cement and artificial fiber, and the sample was prepared by curing and curing. In Comparative Example 2, no artificial fiber was added at all. In the case of Comparative Example 3, the artificial fiber was not premixed with cement, but was added and mixed together with wood chips and other components, molded, cured and cured, and a comparative sample was prepared. Table 1 shows data of physical property tests of the obtained samples.
[0022]
According to Table 1, in Comparative Example 1 using a molding material containing 5% by weight of polypropylene fibers, the artificial fibers are thread-like and do not uniformly disperse on the plate, so that the generation of cracks cannot be completely prevented. Flexibility is not good. Further, Comparative Example 2 in which no artificial fiber is added cannot completely prevent the occurrence of cracks, and the flexibility is not good. Further, Comparative Example 3 in which cement and man-made fiber are not premixed cannot completely prevent the occurrence of cracks, and the flexibility is not good. On the other hand, in each embodiment of the present invention, the occurrence of cracks is completely prevented and the flexibility is good.
[0023]
【The invention's effect】
In the present invention, the cement-based inorganic material and the man-made fiber are premixed and then the wood pieces are mixed. Therefore, the cement-based inorganic material and the man-made fiber can be uniformly mixed without being interfered with the wood pieces, and the result is obtained. The artificial fibers are uniformly dispersed in the hardened cement of the wood chip cement board thus obtained, and cracks can be effectively prevented.

Claims (1)

Premix the cement-based inorganic material and the artificial fiber contained in the range of 0.25 to 4% by weight in the molding material ;
Next, the molding material mixed with the wood pieces is spread on the substrate to form the mat, the mat is pressed in the presence of moisture to be primary cured, and the primary cured body is cured at room temperature or autoclave. A method for producing wood chip cement board.