JP4043687B2 - Wood cement board and method for producing the wood cement board - Google Patents

Description

【００２３】
上記原料組成のうち熱可塑性有機繊維と木片または木質繊維のみをアイリッヒミキサーにて回転混合すると、該熱可塑性有機繊維はほぐされつゝ木片に絡まり綿菓子のような綿状になる。こゝでセメントとリジェクトを添加して更に混合し、最後に硬化促進剤と防水剤および水を添加し混合して原料混合物を調製した。
表１において、比較例１は熱可塑性有機繊維を添加しない試料、比較例２は熱可塑性有機繊維と木片を予じめ混合せず、原料全部を一度に混合して原料混合物を調製した試料である。
【００２４】
実施例１〜２は上記原料混合物を基板上に撒布してマットをフォーミングし、面圧３．９ＭＰa で圧締し、５０℃，１２時間加熱して該マットを一次硬化させ、常温で４日間の二次硬化を行なった。その後熱間ロールプレスで板の表裏面を実施例１では１８０℃、２〜３分間加熱し、実施例２では１４０℃、２〜３分間加熱し、板の表裏面部分の熱可塑性有機繊維を相互融着せしめ点接着させた。実施例３は実施例１、２と同条件の一次硬化の後図４のようなプログラムのオートクレーブ養生中で、実施例４は実施例１、２と同条件の一次および二次硬化の後図５のようなプログラムの乾燥工程中で、それぞれ熱可塑性有機繊維を融着せしめ点接着させた。また実施例５は湿式抄造法により作成した。
このようにして製造した木質セメント板試料の物性を表２に示す。
【００２５】
【表２】

【００２６】
表２に示すように、熱可塑性有機繊維を添加しない比較例１は釘保持力に劣り、また熱可塑性有機繊維と木片とを予かじめ混合せず、原料全部を一度に混合した比較例２では熱可塑性有機繊維相互が絡み合ってダマとなり、板全体に網状に広がらないので、熱可塑性有機繊維の補強効果が小さく、釘保持力は本発明試料よりも小さくなる。
【００２７】
【発明の効果】
本発明ではフォーミングされたマット中に熱可塑性有機繊維の綿状塊中に原料混合物が包含された状態の集合体が存在し、該マットを圧締硬化養生して板とする際に、該熱可塑性有機繊維の綿状塊が板全体に網状に広がり、更に表層および裏層部分では該熱可塑性有機繊維相互が融着し、部分接着もしくは点接着しているから該板が補強されかつ表面クラックの発生が抑制される。
また表面に深い凹凸模様を形成するような場合にも、深い凹凸模様を形成した後に熱可塑性有機繊維を相互に融着し、部分接着もしくは点接着するので表面の崩れもなくなり鮮明な凹凸模様が容易に得られる。そして釘打ちの際の外力が該網状に広がった熱可塑性有機繊維によって分散緩和され、更に木片または木質繊維のまわりに絡みついている熱可塑性有機繊維よって木片または木質繊維が拘束されて割れにくゝなり、また打ち込まれた釘に該熱可塑性有機繊維が絡みつくので、裏面の花咲き現象が抑制されかつ釘保持力が向上する。
【図面の簡単な説明】
【図１】 (1)(2)(3)(4)、熱可塑性有機繊維と木片との混合過程を示す説明図
【図２】 基板上にフォ−ミングされたマットの説明図
【図３】 板の側断面図
【図４】実施例３における一次硬化後のオートクレーブ養生プログラム図
【図５】実施例４における二次硬化後の乾燥工程プログラム図
【符号の説明】
ＯＦ 熱可塑性有機繊維
ＦＬ 木片
ＦＬ’ 木質繊維
Ｐ 粉体
Ｃ 集合体
ＰＲ 製品（板)
Ｍe 融着点[0001]
[Industrial application fields]
The present invention relates to a wood cement board used for, for example, a field board or an exterior material as a roof base material.
[0002]
BACKGROUND OF THE INVENTION
This kind of wood cement board is a so-called wood chip cement board obtained by molding and hardening a raw material mixture mainly composed of wood pieces and cement into a plate shape, and is a board having fire resistance and wood workability. However, since the wood cement board is reinforced only by a coarse piece of wood, when a nail is driven when used for a field board or the like, a thick piece of wood exists in the back layer depending on the place of placement, and the nail is a piece of wood. In so doing, a so-called flower bloom phenomenon occurs where the back side is pushed without being penetrated and the part around the nail is missing. When such a flowering phenomenon occurs, the nail holding power of the plate decreases.
[0003]
[Prior art]
As a means for improving the nailing property of such a wood cement board, it has been proposed to add dry pulp or synthetic fiber to a conventional wood chip cement board (Japanese Patent Laid-Open No. 9-87002).
[0004]
[Problems to be solved by the invention]
A wood cement board is manufactured by a semi-dry method in which a mat is formed by adding water to a raw material mixture mainly composed of wood chips and cement and spreading it on a substrate, and the mat is pressed and cured. In some cases, when a large amount of dry pulp or synthetic fiber is added, the fibers are entangled with each other, resulting in lumps and a sufficient reinforcing effect cannot be obtained. Therefore, when a wood chip cement board is manufactured by a semi-dry method, a large amount of dry pulp or synthetic fiber cannot be added (usually about 0.1 to 2.0% by weight), and the effect of improving nailability is sufficient. I couldn't say that.
[0005]
[Means for Solving the Problems]
The present invention provides, as means for solving the above-described conventional problems, a wood cement board that is a cured product of a raw material mixture containing wood chips FL or wood fibers FL ′ and a cementitious inorganic material, and has a heat The thermoplastic organic fiber network derived from the aggregate C in which the raw material mixture is contained in the flocculent mass of the plastic organic fiber OF is spread out as a whole, and in the surface layer and / or the back layer portion, the thermoplastic organic fiber The fiber OF provides a wood cement board that is fused together.
The thermoplastic organic fiber OF is preferably contained in the wood cement board in an amount of 1.0 to 8.0% by weight.
[0006]
Further, in the present invention, the thermoplastic organic fiber OF and the wood piece FL are mixed by high-speed rotation stirring to form a spongy form in which the thermoplastic organic fiber OF is entangled with the wood piece FL, and then other wood cement board raw materials and water To prepare a raw material mixture, spread the raw material mixture on a substrate, form a mat, press-harden the mat, and a method for producing a wood cement board, and thermoplastic organic fiber OF and wood fiber FL 'And mixing the mixture with high-speed rotating agitation to make the thermoplastic organic fiber OF entangled with the wood fiber FL' and then dispersing it in water together with other wood cement board materials to prepare a raw material slurry, The present invention provides a manufacturing method in which the raw material slurry is made to form a mat and the mat is pressed and cured.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
[Cement-based inorganic powder]
The cement-based inorganic powder used in the present invention is a hydraulic inorganic material mainly composed of calcium silicate. As such an inorganic material, for example, Portland cement or Portland cement mixed with blast furnace slag is used. There are blast furnace cement, fly ash cement mixed with fly ash, silica cement mixed with silica materials such as volcanic ash and clay, alumina cement, blast furnace slag and the like.
[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 surface layer, 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 and the thickness is What is 0.5 to 2 mm (medium grain piece) is preferable, and for core layers in a three-layer structure, the average length is 5 to 20 mm and the thickness is 0.8 to 2.5 mm (coarse grain piece) Is 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 a flower bloom phenomenon.
[0009]
[Wood fiber]
The wood fiber used in the wet method of the present invention is preferably wood fiber such as kraft pulp, waste paper or virgin pulp.
[0010]
[Thermoplastic organic fibers]
The thermoplastic organic fiber used in the present invention is a fiber of a thermoplastic resin such as a polyamide fiber, a polyester fiber, a polyethylene fiber, or a polypropylene fiber, but in addition to the thermoplastic fiber, a polyvinyl alcohol fiber (vinylon), Examples thereof include polyvinyl chloride fibers such as polyvinyl chloride and polyvinylidene chloride, synthetic fibers such as polyurethane fibers, polyoxymethylene fibers, polytetrafluoroethylene fibers, benzoate fibers, and polyimide fibers. The fibers may be recycled fibers obtained by defibrating scraps of fiber sheets such as nonwoven fabrics, knitted fabrics, and felts. The fiber is preferably a single fiber having a diameter of 0.1 mm or less.
[0011]
[Other ingredients]
In the wood cement board of the present invention, magnesium chloride, magnesium sulfate, calcium chloride, calcium sulfate, sodium aluminate, potassium aluminate, aluminum sulfate, water glass, etc., as components other than the above-mentioned cement-based inorganic material and thermoplastic organic fiber Hardening accelerator, mineral powder such as vermiculite, bentonite, wood cement board, wood cement board waste material such as wood fiber cement board (reject), waterproofing agent such as wax, paraffin, silicon, synthetic resin emulsion, etc. A replenishing material, a foamable thermoplastic bead, a plastic foam or the like may be added.
The above examples are not intended to limit the present invention.
[0012]
[Composition of wood cement board]
In the raw material mixture of the wood cement board of the present invention, the cement-based inorganic material is preferably 55 to 90% by weight, the wood piece is preferably 10 to 45% by weight, and the thermoplastic organic fiber is a synthetic fiber. Is 1.0 to 5.0% by weight, preferably 1.5 to 2.5% by weight, and in the case of wood fiber, 3 to 20% by weight, preferably 5 to 10% by weight.
In the raw material mixture, if the mixture ratio of the wood pieces is less than 10% by weight, the reinforcing effect by the wood pieces is not sufficient, and if the mixture ratio of the wood pieces exceeds 45% by weight, the amount of the cement-based inorganic material is relatively reduced. The consolidation of the cement-based inorganic material is hindered, and the strength tends to decrease.
If the amount of the thermoplastic organic fiber added is less than the above range, the effect of improving the nailability is not significant, and if it exceeds the above range, the fibers are easily entangled with each other.
[0013]
[Manufacture of wood cement board]
The wood cement board of the present invention is preferably produced by a semi-dry method or a wet papermaking method. Particularly, in the wood cement board produced by these methods, the effect of preventing or suppressing the flowering phenomenon is remarkable.
[0014]
In the case of the semi-dry method, first, the thermoplastic organic fiber and the wood piece are stirred at high speed using a forced stirring type mixer such as a rotary mixer. If it does so, the said thermoplastic organic fiber will become cotton shape, entangled with a piece of wood.
[0015]
After the thermoplastic organic fiber is entangled with wood pieces and made into a cotton shape as described above, powder raw materials such as cement-based inorganic material, mineral powder, reject, etc. are added and mixed, and then water-proofing agent, hardening accelerator and water are added and mixed To prepare a raw material mixture. The amount of water added is such that the water content in the raw material mixture is usually 15 to 50% by weight. However, when the reinforcing material is wood fiber, a thermoplastic organic fiber and wood fiber are forcibly stirred. It is desirable to add a small amount of water in advance when the powder raw material is added and mixed after the thermoplastic organic fiber is entangled with the wood fiber by stirring at high speed.
[0016]
The raw material preparation process is shown in Fig. 1 (1), (2), (3) and (4). When the wood piece FL and the thermoplastic organic fiber OF are stirred at high speed in (1), the thermoplastic organic fiber OF is entangled with the wood piece FL as shown in (2). When stirring at a higher speed, as shown in (3), agglomeration of the pieces of wood entangled with the thermoplastic organic fibers OF begins to occur, and the agglomerates contain air and swell into a cotton candy shape. When the powder raw material P such as cement is added and stirred at a high speed, the wood piece FL having the powder raw material P such as cement attached to the surface is heated like cotton candy as shown in (4). Aggregates C are formed which are scattered and contained in a flocculent mass of plastic organic fibers or thermoplastic organic fibers.
Such a raw material mixture including the aggregate C is distributed on a substrate B such as a template or a conveying plate, and a mat M as shown in FIG. 2 is formed.
[0017]
When the mat M including the aggregate C is formed as described above, the mat M is pressed together with the substrate to be primarily cured in a heated state. 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 5 days, and the autoclave curing is normally performed at a humidity of 85% RH or higher and a temperature of 130 to 180 ° C. for 4 to 18 hours. After normal temperature curing or autoclave curing, a surface treatment is performed through a drying process to obtain a wood cement board.
[0018]
When a concavo-convex pattern is provided on the surface of the wood 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 wooden cement board without an uneven | corrugated pattern on the surface, you may use a conveyance board directly as a board | substrate.
[0019]
In the case of the wet papermaking method, similar to the semi-dry method, thermoplastic organic fibers are entangled with wood fibers to form a cotton, and then dispersed in water together with other wood cement board raw materials similar to the semi-dry method to form a raw material slurry. To do. The raw slurry is usually prepared with a solid content concentration of about 10 to 20% by weight, poured onto a long filter cloth with good drainage to form a papermaking layer, and the papermaking layer is wound into a plurality of layers on a making roll. The laminated mat that has been cut and developed at a predetermined thickness is usually formed by pressure forming with a flat plate press or roll press to form a formed mat. The molding mat is usually press-cured under the above conditions, and then cured at room temperature for 2 to 5 days as described above, or autoclaved for 4 to 18 hours at a temperature of 130 to 180 ° C. at a humidity of 85% RH or higher. The
[0020]
The wood cement board produced by the semi-dry method or the wet papermaking method, the surface layer and / or the back layer part is heated to a temperature higher than the softening point of the thermoplastic organic fiber, and the surface layer and / or the back layer part Thermoplastic organic fibers are fused together and partially bonded or spot bonded.
The surface layer and / or the back layer portion of the wood cement board is heated during autoclave curing, in a heating plate, in a hot roll press, or in a heating process in a drying process.
[0021]
In the product PR, as shown in FIG. 3, the cotton-like thermoplastic organic fiber OF is entangled with the wood piece FL and spreads in a net-like manner on the entire board, and in the front and back layer portions, the thermoplastic organic fibers are point Me. As a result, the plate is reinforced and the rigidity is improved, and when the breaking load is applied, fiber pull-out from the surface is reduced and surface cracks are generated. Is suppressed, the flower bloom phenomenon at the time of nailing is prevented, and the nailability is improved. And even when forming a deep concavo-convex pattern on the surface of the plate, after forming the concavo-convex pattern, the thermoplastic organic fiber OF is heat-fused and partially bonded or spot-bonded, so the fiber network breaks or the surface collapses. There is no fear of
If a deep concavo-convex pattern is formed on the back side of the plate after the fiber net is inserted inside the plate, particularly near the surface, the fiber network is broken or the surface is broken. It is usually difficult to form a fiber network in a plate by a wet papermaking method, but in the present invention, a net effect can be obtained by fusing thermoplastic organic fibers in place of a fiber network in the plate even in the wet papermaking method.
[0022]
〔Example〕
Table 1 shows the raw material composition of each material.
[Table 1]

[0023]
When only thermoplastic organic fibers and wood pieces or wood fibers of the above raw material composition are rotated and mixed with an Eirich mixer, the thermoplastic organic fibers are entangled with the wood pieces and become cottony like cotton candy. Cement and reject were added thereto and further mixed. Finally, a hardening accelerator, a waterproofing agent and water were added and mixed to prepare a raw material mixture.
In Table 1, Comparative Example 1 is a sample to which no thermoplastic organic fiber is added, and Comparative Example 2 is a sample in which a raw material mixture is prepared by mixing all the raw materials at once without mixing thermoplastic organic fibers and wood pieces in advance. is there.
[0024]
In Examples 1 and 2, the above raw material mixture was spread on a substrate, the mat was formed, pressed at a surface pressure of 3.9 MPa, heated at 50 ° C. for 12 hours to primarily cure the mat, and then at room temperature for 4 days. Secondary curing was performed. Thereafter, the front and back surfaces of the plate are heated at 180 ° C. for 2 to 3 minutes in Example 1 with a hot roll press, and the thermoplastic organic fibers on the front and back surfaces of the plate are heated at 140 ° C. for 2 to 3 minutes in Example 2. They were fused together to make point bonds. Example 3 is the autoclave curing of the program as shown in FIG. 4 after the primary curing under the same conditions as in Examples 1 and 2, and Example 4 is the figure after the primary and secondary curing under the same conditions as in Examples 1 and 2. In the drying process of the program as in No. 5, the thermoplastic organic fibers were fused and adhered to each other. Example 5 was prepared by a wet papermaking method.
Table 2 shows the physical properties of the wood cement board samples thus produced.
[0025]
[Table 2]

[0026]
As shown in Table 2, Comparative Example 1 in which the thermoplastic organic fiber was not added was inferior in nail holding power, and the thermoplastic organic fiber and the wood piece were not preliminarily mixed, but all the raw materials were mixed at one time. Then, the thermoplastic organic fibers are entangled with each other and become lumps and do not spread in a net shape on the entire plate. Therefore, the reinforcing effect of the thermoplastic organic fibers is small, and the nail holding force is smaller than that of the sample of the present invention.
[0027]
【The invention's effect】
In the present invention, there is an aggregate in which a raw material mixture is contained in a cotton-like lump of thermoplastic organic fibers in a formed mat, and when the mat is pressed and cured to form a plate, A cotton-like lump of plastic organic fibers spreads in a net-like pattern throughout the board, and the thermoplastic organic fibers are fused to each other in the surface layer and back layer part, so that the board is reinforced and surface cracked. Is suppressed.
Also, when forming a deep concavo-convex pattern on the surface, after forming the deep concavo-convex pattern, the thermoplastic organic fibers are fused to each other and partially bonded or spot-bonded, so the surface does not collapse and a clear concavo-convex pattern is formed. Easy to get. The external force at the time of nailing is dispersed and relaxed by the thermoplastic organic fibers spread like a net, and the wooden pieces or wood fibers are restrained by the thermoplastic organic fibers entwined around the wood pieces or wood fibers, so that they are not easily broken. In addition, since the thermoplastic organic fibers are entangled with the nail that is driven, the flower bloom phenomenon on the back surface is suppressed and the nail holding power is improved.
[Brief description of the drawings]
[Fig. 1] (1) (2) (3) (4), explanatory diagram showing the mixing process of thermoplastic organic fibers and wood pieces [Fig. 2] explanatory diagram of the mat formed on the substrate [Fig. [Figure 4] Side cross-sectional view of the plate [Fig. 4] Autoclave curing program diagram after primary curing in Example 3 [Fig. 5] Drying process program diagram after secondary curing in Example 4 [Explanation of symbols]
OF Thermoplastic organic fiber FL Wood piece FL 'Wood fiber P Powder C Aggregate PR Product (board)
Me fusion point

Claims (4)

A wood cement board, which is a cured product of a raw material mixture containing wood chips or wood fibers and a cement-based inorganic material, wherein the raw material mixture is contained in a cotton-like lump of thermoplastic organic fibers inside The thermoplastic organic fiber network derived from the above is spread as a whole, and the thermoplastic organic fibers are fused to each other in the surface layer and / or the back layer portion. 2. The wood cement board according to claim 1, wherein the thermoplastic organic fiber is contained in the wood cement board in an amount of 1.0 to 8.0% by weight. A thermoplastic organic fiber and wood pieces are mixed by high-speed rotational stirring to form a cotton-like form in which the thermoplastic organic fibers are entangled with the wood pieces, and another wood cement board raw material and water are added and mixed to form a raw material mixture. 3. The method for producing a wood cement board according to claim 1 or 2, wherein the raw material mixture is prepared and spread on a substrate to form a mat, and the mat is pressed and cured. The thermoplastic organic fiber and wood fiber are mixed by high-speed rotation stirring to form a cotton-like entangled thermoplastic fiber and then dispersed in water together with other wood cement board materials to form a raw material slurry. The method for producing a wood cement board according to claim 1 or 2, wherein the raw slurry is prepared, the mat is formed, the mat is formed, and the mat is pressed and cured.

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