JP2001139363A - Cemented wooden board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a cemented wooden board having high strength, excellent dimensional stability and superior properties with respect to decorative design by effectively utilizing a cemented wooden board waste material. SOLUTION: The production process for this cemented wooden board comprises subjecting a cemented wooden board waste material to primary crushing into a primarycrushed material 1 by an impact crusher, further subjecting the primary-crushed material 1 to secondary crushing into a secondary-crushed material 1A by a grinding mill, classifying the secondary- crushed material 1A into coarse powder having 45-1,000 μm, or desirably 75-1,000 μm grain size, and fine powder having 1-500 μm, or desirably 1 to <75 μm grain size, and using the coarse powder as a raw material for a surface layer and a rear layer of the cemented wooden board and also using the fine powder as a raw material for a core layer of the cemented wooden board.

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 mixed with wood cement board waste material powder.

[0002]

2. Description of the Related Art As a wood cement board, there is provided a three-layered structure comprising a front and back layer having a dense structure and a core layer having a coarse structure. Since the above wood cement board has a smooth surface and a core part has cushioning properties, embossing on the surface can provide a sharp design pattern with high designability. In order to obtain the front and back layers having such a dense structure, wood powder is blended with a raw material mixture for forming the front and back layers. However, wood flour has a small particle size and a large specific surface area, and a large amount of a cement hardening inhibitor such as lignin contained in the wood flour elutes into the raw material mixture, causing poor hardening of the cement, causing a reduction in the strength of the product, There is a problem that even if a sharp uneven pattern is formed, the edge portion is chipped.

[0003] The wood cement board has a structure in which a wood reinforcing material is dispersed in a hardened cement matrix. When manufacturing the wood cement board, waste materials such as chips and chips are removed from the product in a cutting step. Although about 30% is generated, such wood cement board waste has been mainly disposed of conventionally. However, in view of the fact that pollution regulations are strict and that it is difficult to secure a disposal site and disposal costs are increasing, there is a strong demand for the reuse of wood cement board waste. If a wood cement board is manufactured by mixing a pulverized wood cement board waste material with a wood cement board raw material, the wood cement board waste material is highly reused. For example, Japanese Patent Application Laid-Open No. 9-286657 discloses a 16 waste cement board
It has been proposed to pulverize to a particle size smaller than the mesh and mix it with the raw material of the wood cement board.

[0004]

However, wood cement board waste consists of wood reinforcing material and cement hardened material.
There is a problem that a large amount of the mixture causes a decrease in the strength of the product due to poor curability.

[0005]

The present invention provides a wood cement board having a three-layer structure comprising a front and back layer having a dense structure and a core layer having a coarse structure as means for solving the above-mentioned conventional problems. The wood cement board waste material pulverized material is classified into a coarse powder and a fine powder, the wood cement board waste material coarse powder is added to the front and back layers, and the wood cement board waste material fine powder is added to the core layer. The present invention provides a wood cement board to which an additive is added. The wood cement board waste material coarse powder and fine powder are obtained by firstly pulverizing the wood cement board waste material with an impact type pulverizer, further subjecting the primary pulverized material (1) to secondary pulverization with a grinding pulverizer, Desirably, it is obtained by classifying (1A). Further, the wood cement board waste material coarse powder has a particle size of 45 μm or more and 1000 μm or less, and the wood cement board waste material fine powder preferably has a particle size of 1 μm or more and 500 μm or less. More preferably, the wood cement board waste material coarse powder is A particle size of 75 μm or more and 1000 μm or less,
The wood cement board waste material fine powder has a particle size of 1 μm or more and 75 μm.
Desirably less than. Preferably, the wood cement board waste material coarse powder contains 25 to 50% by weight of the woody component, and the wood cement board waste material fine powder contains 60 to 90% by weight of the inorganic component. Furthermore, the wood cement board waste powder coarse powder is 20 on the front and back layers of the wood cement board.
It is preferable that the wood cement board waste powder is added to the core layer in an amount of 40% by weight or less. In addition, the wood cement board may be added with a primary pulverized wood cement board waste material (1) instead of a part of the wood cement board waste material coarse powder and / or fine powder. The wood cement board waste material desirably contains a wood fiber bundle as a wood reinforcing material and is manufactured by a dry method. The present invention will be described in detail below.

The wood reinforcing materials used in the present invention include wood chips, wood fiber bundles, wood wool, wood flour, wood pulp and the like, which are the same as those used in conventional wood cement boards. Desirable wood reinforcement is 0.5-2m wide
m, length 1-20mm, aspect ratio (length / thickness) 20
~ 30 pieces of wood, 0.1 ~ 2.0mm in diameter, 2-3 length
There is a 5 mm, preferably 10-30 mm, bundle and / or wood fiber bundle that has been bulked by bending and / or bending.

Examples of the cement used in the present invention include portland cement, blast furnace slag cement, silica cement, fly ash cement, alumina cement and the like.

The wood cement board waste material to which the present invention is applied is a waste material generated when a cement board reinforced with the above-mentioned wood reinforcing material is used for, for example, demolishing or renovating a building used as an outer wall material or a similar material, and the like. Alternatively, chips, chips, or the like generated in a cutting step or the like when manufacturing the wood cement board.

The above wood cement board waste is pulverized by an impact type pulverizer into a primary pulverized product usually having a particle size of 0.5 to 2.0 mm, and the primary pulverized product is also used as a raw material of the wood cement board. In the present invention, in addition to or instead of the primary pulverized material, a secondary pulverized material having a particle size of 1 μm or more and 1000 μm or less, which is obtained by secondary pulverizing the primary pulverized material with a grinding pulverizer, is used as a raw material. As an impact type crusher,
There are a hammer mill, an impact mill, and the like, and examples of the grinding-type pulverizer include a centrifugal roller mill, a baul mill, a zegomil, an ong mill, and a vertical mill using a vertical roller.

[0010] The secondary pulverized product is a coarse powder having a particle size of 45 µm or more and 1000 µm or less, preferably 75 µm or more and 1000 µm or less by sieving or air classification.
μm or more and 500 μm or less, desirably 1 μm or more and 75 μm
m and a fine powder of less than 25 m.
It contains 50% by weight of a woody component and 50 to 75% by weight of an inorganic component, and the fine powder usually contains 10 to 40% by weight of a woody component and 60 to 90% by weight of an inorganic component. The particle size distribution of the coarse powder used in the present invention is 16 to 50 mesh 5 to 15% by weight 50 to 100 mesh 20 to 30% by weight 100 to 200 mesh 40 to 70% by weight 200 to 330 mesh 5 to 15% by weight The average particle size is 80 to 100 μm. The particle size distribution of the fine powder used in the present invention is 50 to 200 mesh 10 to 20 wt% 200 to 330 mesh 20 to 40 wt% 330 mesh or less 40 to 70 wt%, and the average particle size is 20 to 40 μm.

In the present invention, in particular, a particle diameter of 75 μm containing 35 to 50% by weight of a woody component and 50 to 65% by weight of an inorganic component.
It is preferable to use a coarse powder having a particle size of m to 300 μm, a fine powder having a particle size of 5 μm to 45 μm including 10 to 20% by weight of a woody component and 80 to 90% by weight of an inorganic component.

In addition to the above-mentioned raw materials, a part of cement is further divided into silica sand, silica stone powder, silica fume, blast furnace slag, fly ash, shirasu balloon, pearlite, bentonite,
It may be replaced with a silicate-containing substance such as diatomaceous earth, or an anhydride or crystallized chloride such as calcium chloride, magnesium chloride, iron chloride, aluminum chloride, sodium chloride, potassium chloride, lithium chloride, or aluminum sulfate. , Alum, iron sulfate, lithium sulfate, sodium sulfate, potassium sulfate, anhydrous or crystallized sulfate such as magnesium sulfate, calcium nitrate, nitrate such as calcium nitrite, anhydrous or crystallized nitrite, calcium formate, Formate such as calcium acetate, anhydride or crystallized acetate, sodium aluminate,
A cement hardening accelerator such as water glass, a water repellent such as wax, paraffin, and silicone, and an expandable thermoplastic plastic bead such as an expandable polystyrene bead may be added.

The wood cement board of the present invention has a three-layer structure in which a front and back layer having a dense structure are laminated on the front and back surfaces of a core layer having a rough structure. In the case of such a three-layer wood cement board, the basic composition other than the coarse powder and the fine powder of the wood cement board waste material of the raw material mixture A of the front and back layers and the raw material mixture B of the core layer is usually 30 to 70 weight of cement. %, Wood reinforcement 5
The basic composition of the raw material mixture A for the front and back layers is preferably 30 to 60% by weight of cement, 15 to 50% by weight of a silicic acid-containing substance, 0 to 15% by weight of pearlite, wood chips and / or wood flour 5 to 35% by weight. 20% by weight, and more preferably the basic composition of the raw material mixture B for the core layer is cement 30 to 6
0% by weight, silicic acid-containing substance 15-50% by weight, perlite 0-15% by weight, wood fiber bundle 5-25% by weight, wood chip 0
10 to 10% by weight and expandable polystyrene beads 0.5 to 5% by weight.

Further, in addition to the basic composition, the raw material mixture A of the front and back layers has a coarseness of a secondary pulverized material of wood powder having a particle size of 0.1 to 1.5 mm and wood cement board waste material having a particle size of 45 μm to 1000 μm. 0 to 20% by weight in total, desirably 3 to 20% by weight, and in the raw material mixture B for the core layer, 0 to 40% by weight of a fine powder of secondary pulverized wood cement board waste material having a particle size of 1 μm or more and 500 μm or less. %, Preferably 29-4
0% by weight is added. The mixing ratio of the wood flour and the coarse powder of the secondary pulverized wood cement board waste material is 40:60 to 0:
Preferably, it is set to 100. When the ratio of replacing the wood powder with the coarse powder is less than 60% by weight, the amount of the cement hardening inhibitor contained in the wood powder is increased, and the cement hardening failure becomes remarkable. In the above-mentioned three-layered wood cement board, the raw material mixture A of the front and back layers is usually made of a fine reinforcing material such as a piece of wood having a grain size of 4.5 mm or less as a wooden reinforcing material to give a dense structure. The raw material mixture B of the core layer is usually provided with a mesh as a wood reinforcing material in order to give a coarse structure.
5mm to 10mm particle size wood chip, average diameter 1.0mm, length 20
Use a coarse wood reinforcement such as a mm fiber bundle. Further, in the present invention, the primary pulverized material is replaced by a part of fine powder and / or coarse powder of the secondary pulverized wood cement board waste material in the front and back layers of 0 to 2% by weight and in the core layer by 0 to 2% by weight.
8% by weight may be used.

As a method for producing a wood cement board of the present invention, it is desirable to employ a dry production method in which the steps can be easily made continuous and the equipment is simple. In step 1 of the dry manufacturing method, the raw material mixture A is sprinkled on a template in a mat shape,
Next, the raw material mixture B was sprayed thereon in a mat shape,
Further, the raw material mixture A is sprayed thereon in the form of a mat. At this time, water is added to the raw material mixture A and the raw material mixture B in an amount of 30 to 50% by weight for a hardening reaction of the cement. The addition of wood chips to the raw material mixture B and the use of wood fiber bundles that have been made bulky by the above-mentioned branching and / or bending and / or bending make it easier for the raw material mixture B to be unraveled and on the template. It becomes easy to spray evenly.

In the continuous manufacturing method, a large number of the above-mentioned templates are placed on a belt conveyor. If desired, the raw material mixture spread on the template is slightly pressed by a roll or the like to form a mat, which is then pre-pressed and hardened in step 2 in the presence of moisture to form a desired shape.

The pressing condition is usually 1.0 to 3.0MP.
a) The temperature is 60 to 80 ° C., the time is about 6 to 20 hours, and the heating is usually performed with steam. Pressing is performed by clamping the mat between two template plates, but the template plate surface may be given a predetermined shape, an uneven pattern, or the like. The pre-cured product obtained by the pressing pre-curing in step 2 is cured in an autoclave in step 3.

The curing conditions are usually at a pressure of 0.6 to 2.0 MPa.
The temperature is 160 to 180 ° C. and the time is about 5 to 10 hours. The calcium silicate reaction between the cement and the silicate-containing substance is completely performed by the autoclave curing, and when expandable thermoplastic beads are added to the core layer, the expandable thermoplastic beads are completely expanded. The plastic foam particles formed by foaming of the expandable thermoplastic plastic beads are melted, and the foaming agent in the cells escapes to the outside world. Holes are formed. Then, a thermoplastic plastic coating layer is formed on the inner wall surface of the pore based on the plastic foam particles.

In the step 3, curing may be performed, for example, at a normal temperature of 25 ° C. for 4 to 10 days. However, in this case, it is desirable to reduce the compounding ratio of the silicic acid-containing substance to increase the cement content. Thus, the wood cement board of the present invention is manufactured. The thickness of the front and back layers of the wood cement board of the present invention is usually 10 to 30% of the total thickness, and the density is 0.9 to 1.1 g / cm ^3. And

[0020]

When the wood cement board waste is pulverized by an impact type pulverizer, the pulverized material (1) obtained as shown in FIG.
It has a hardened cement (2) on the outside and an unreacted cement component (3) on the inside. Such crushed material
When (1) is further pulverized by a grinding type pulverizer, the secondary pulverized product (1A) obtained as shown in FIG. 2 has a particle size range of 1 μm or more and 1000 μm or less, and an unreacted cement component ( 3)
Will be exposed to the outside. Therefore, such a secondary pulverized product (1A) has high reactivity and causes a hardening reaction together with the cement in the wood cement. In particular, in the present invention, the secondary pulverized product (1A) is further mixed with a coarse powder having a particle size of 45 μm to 1000 μm, preferably 75 μm to 1000 μm, and a particle size of 1 μm to 500 μm, preferably 1 μm to 7 μm.
Since coarse powder containing a large amount of woody components is classified into fine powders having a particle size of less than 5 μm and added to the front and back layers, the wood reinforcement for the front and back layers can be saved. In particular, in the present invention, the wood powder is replaced by the coarse powder, but the wood reinforcing material in the waste material of the wood cement board is eluted to a certain extent by the heating at the time of manufacturing the wood cement board, and the cement hardening inhibitor is eluted to some extent. Therefore, the amount of the cement-hardening-inhibiting substance eluted from the coarse powder is very small, and poor cement-hardening can be prevented. As mentioned above, the particle size of the wood flour used for the front and back layers is
Although the average is 1.0 mm, the coarse powder is finer than that, and even if it is replaced with wood powder, the surface smoothness of the wood cement board is improved rather than hindered.

On the other hand, the fine powder is added to the core layer, but has a higher reactivity than the above coarse powder, so that a hardening reaction is favorably caused together with the cement. Nearly 60% of the cement component remains as an unreacted material immediately after production of the wood cement board, and the unreacted material is filled in the pores of the hardened cement matrix. When the unreacted material is filled in the pores of the hardened cement matrix, the dimensional stability of the wood cement board deteriorates. In the present invention, the fine powder is also filled in the pores of the cement hardened material matrix in the core layer, and the fine powder contains the hardened cement which has been reacted in addition to the unreacted cement component, so that it is filled as an aggregate. This has an effect, making it difficult for water or the like to enter the pores, and thereby suppressing shrinkage and swelling. Further, since the reactant reacts to some extent with the unreacted substances remaining on the wood cement board in the pores, the dimensional stability of the wood cement board is greatly improved.

When a three-layer structure as in the present invention is used as the wood cement board waste material, the components used in the core layer, for example, the wood fiber bundle, are also contained in the front and back layers. The composition of the layers tends to be closer to each other, the difference in physical properties between the front and back layers and the core layer is reduced, and the delamination strength is improved. Therefore, the coarse powder and fine powder of the wood cement board waste material of the present invention can be replaced not only with wood flour but also with a flat piece of wood so that the structure becomes uniform, and cement and silicic acid-containing substances can be replaced. The part can be replaced, and the entanglement with the wood reinforcing material becomes stronger than that of fine powder such as cement, and the strength of the board is improved.

[0023]

EXAMPLE A sample of the present invention, which is a three-layered wood cement board having a front and back layer portion and a core layer portion, using a mixture of water having a composition shown in Table 1 and 40 to 50% by weight of water. 1, 2, 3, 4, 5, 6, 7 (Examples 1 to 7) and Comparative Sample 1 (Comparative Example 1) were prepared by a dry method.

For the sample and the comparative sample, a predetermined amount of a mixture of the surface layer composition shown in Table 1 was sprayed on a lower mold plate to form a surface layer mat, and a mixture of the core layer composition shown in Table 1 was further formed thereon. Spray a predetermined amount to form the core layer mat,
Further, a predetermined amount of the mixture of the above-mentioned surface layer composition is sprayed thereon to form a back layer mat, and the upper mold plate is brought into contact therewith, pressed under pressure, hardened, cured and dried under the conditions shown in Table 1. Weight ratio of front / back layer / core layer = 1 with three-layer structure
/ 3 wood cement board samples were prepared. Various physical properties of each sample thus prepared were measured. The results are shown in Table 2.

[0025]

[Table 1]

[0026]

[Table 2]

Referring to Table 2, the particle size of the front and back layers is 0.1 to 0.1.
0 to 5% by weight of wood flour in the range of 1.5 mm and 3 to 3 mm of coarse wood cement board waste powder having a particle size of 45 μm or more and 1000 μm or less.
20% by weight, and the core layer has a particle size of 1%.
Sample 1 of the present invention, in which the wood cement board waste material fine powder in an amount of 40 wt% or less is contained
2,3,4,5,6,7 (Examples 1 to 7) have a particle size of 0.5
Comparative sample 1 in which crushed wood cement board waste material of about 2.0 mm was added to the front and back layers at about 1% by weight and the core layer at about 27% by weight.
Strength and dimensional stability were improved as compared with (Comparative Example 1).

[0028]

According to the present invention, in addition to adding the pulverized material of the wood cement board waste material by the impact type pulverizer, the pulverized material is secondarily pulverized by the attrition type pulverizer and classified into coarse powder and fine powder. Since the coarse powder is added to the front and back layers and the fine powder is added to the core layer, the waste material of the wood cement board is effectively used to have high strength and good dimensional stability. It is possible to provide a wood cement board having a pattern and a high design property.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a primary pulverized product by a conventional impact type pulverizer.

FIG. 2 is an explanatory view of a secondary pulverized product by the attrition pulverizer of the present invention.

[Explanation of symbols]

 1 Primary crushed material 1A Secondary crushed material

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) E04C 2/26 E04C 2/26 P // B09B 3/00 ZAB B09B 3/00 301Z 301 ZAB

Claims (8)

[Claims] 1. A wood cement board having a three-layer structure comprising a front and back layer having a dense structure and a core layer having a coarse structure, wherein a crushed material of the wood cement board is classified into a coarse powder and a fine powder. The wood cement board waste material coarse powder is added to the front and back layers, and the wood cement board waste material fine powder is added to the core layer. 2. The wood cement board waste material coarse powder and fine powder are subjected to primary pulverization of the wood cement board waste material by an impact type pulverizer, and the primary pulverized material is further pulverized by an attrition type pulverizer. The wood cement board according to claim 1, which is obtained by classifying the pulverized material. 3. The coarse powder of the wood cement board waste material has a particle size of 45 μm.
2. The wood cement board waste material fine powder has a particle size of 1 μm or more and 500 μm or less.
Or the wood cement board according to 2 4. The coarse powder of the wood cement board waste material has a particle size of 75 μm.
3. The wood cement board according to claim 1, wherein the wood cement board waste powder has a particle size of 1 μm or more and less than 75 μm. 5. The wood cement board waste material coarse powder contains 25 to 50% by weight of a woody component, and the wood cement board waste material fine powder contains an inorganic component of 60 to 90% by weight. Wood cement board according to 4 6. The wood cement board waste material coarse powder is added to the front and back layers in an amount of 20% by weight or less, and the wood cement board waste material fine powder is added to the core layer in an amount of 40% by weight or less. The wood cement board according to any one of claims 1 to 5, wherein 7. The wood cement board to which a primary pulverized wood cement board waste material is added in place of a part of the wood cement board waste material coarse powder and / or fine powder.
Wood cement board according to 6 8. The wood cement board according to claim 1, wherein the wood cement board and the wood cement board waste material contain a wood fiber bundle as a wood reinforcing material and are manufactured by a dry method.