JP3499200B2 - Wood cement board - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a wood cement board in which powder of wood cement board waste material is mixed.

[0002]

2. Description of the Related Art As a wood cement board, there is provided a wood cement board having a three-layer structure comprising front and back layers having a dense structure and a core layer having a rough structure. Since the surface of the above-mentioned wood cement board is smooth and the core portion has a cushioning property, if the surface is embossed, a sharp relief pattern having a high design can be obtained. In order to obtain the front and back layers having such a dense structure, wood powder is added to the raw material mixture for forming the front and back layers. However, wood powder has a small particle size and a large specific surface area, causing a large amount of cement hardening inhibiting substances such as lignin contained in wood powder to elute into the raw material mixture to cause poor hardening of cement, causing a decrease in strength of the product, Even if a sharp uneven pattern is formed, the edge portion may be chipped.

A wood cement board has a structure in which a wood reinforcing material is dispersed in a cement hardened product matrix, and when manufacturing the wood cement board, waste materials such as chips and scraps are contained in the product in a cutting process. About 30% occurs,
Conventionally, such wood cement board waste materials have been mainly discarded. However, in view of the current situation that the pollution control is strict and the disposal site is difficult to secure and the disposal cost is high, it is strongly desired to reuse the wood cement board waste material. If a pulverized product of the wood cement board waste material is mixed with a wood cement board raw material to produce a wood cement board, the wood cement board waste material is highly reused. For example, Japanese Patent Laid-Open No. 9-286657 discloses wood materials. Waste cement board 1
It has been proposed to pulverize to a particle size of 6 mesh or less and mix it with the raw material of the wood cement board.

[0004]

However, since the wood cement board waste material is composed of a wood reinforcing material and a cement hardened material and has poor hardening properties, there is a problem that a large amount of mixing causes a decrease in strength of the product.

[0005]

Means for Solving the Problems As means for solving the above-mentioned conventional problems, the present invention provides cement 30 to 60% by weight, silicic acid-containing substance 15 to 50% by weight, and pearlite 0.
〜15% by weight, wood chips with a grain size of 4.5 mm or less and / or 5 to 20% by weight, and a grain size of 0.1 to 1.5 mm and a grain size of 45 μm to 1000 μm and average Wood cement board waste powder having a particle size of 80 to 100 μm, front and back layers made of a cured product of a mixture containing a total of 3 to 20% by weight, 30 to 60% by weight of cement, and a silicic acid-containing substance 1
5 to 50% by weight, perlite 0 to 15% by weight, wood fiber bundles 5 to 25% by weight, wood chips with a grain size of 4.5 mm to 10 mm 0 to 10% by weight, expandable polystyrene beads 0.5 to
5% by weight, particle size 1 μm or more and 500 μm or less, and average particle size 20 to 40 μm Wood cement board waste wood fine powder 7 to 40
It is intended to provide a wood cement board having a three-layer structure including a core layer made of a cured product of a mixture containing wt%. The coarse powder and fine powder of the wood cement board waste material are first crushed with an impact type crusher, and the primary crushed product (1) is further crushed with an attrition crusher, and the secondary crushed product is used.
It is desirable to obtain it by classifying (1A).
In addition, the wood cement component waste powder contains 25 wood components.
˜50% by weight, the wood cement board waste powder fine powder preferably contains an inorganic component in an amount of 60 to 90% by weight, and more preferably the wood cement board waste wood coarse powder and / or Alternatively, it is preferable that a primary pulverized product of wood cement board waste material is added in place of a part of the fine powder. Further, it is desirable that 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. The present invention is described in detail below.

The wood reinforcing material used in the present invention includes wood chips, wood fiber bundles, wood wool, wood flour, wood pulp, etc.
There are similar wood reinforcing materials used for conventional wood cement boards. Width 0.5 to 2 as a desirable wood reinforcement
mm, length 1 to 20 mm, aspect ratio (length / thickness) 20
~ 30 wood pieces, diameter 0.1-2.0mm, length 2-3
There is a 5 mm, preferably 10 to 30 mm, branch and / or bow and / or fold bulked wood fiber bundle.

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

The wood cement board waste material targeted by the present invention is a waste material generated when the cement board reinforced by the wood reinforcing material is used as, for example, an exterior wall material or a homogenous member, when the building is demolished or repaired, Alternatively, they are chips, scraps, and the like that are generated in a cutting process or the like when the wood cement board is manufactured.

The waste wood cement board waste is crushed by an impact crusher into a primary crushed product having a particle size of 0.5 to 2.0 mm, and the primary crushed product is also used as a raw material for the wood cement plate. In the invention, in addition to the primary pulverized product or in place of the primary pulverized product, the secondary pulverized product having a particle size of 1 μm or more and 1000 μm or less obtained by secondary pulverizing the primary pulverized product with a grinding mill is used as a raw material. There are hammer mills, impact mills, etc. as impact type crushers, and centrifugal roller mills, bawl mills, zego mills, as milling type crushers.
There are an Ong mill and a vertical mill using a vertical roller.

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, and a particle size of 1 μm or more and 500 μm or less, preferably 1 μm or more 75
It is classified into fine powder of less than μm, and the coarse powder is usually 25
˜50 wt% wood component and 50-75 wt% inorganic component are contained, and the fine powder usually contains 10-40 wt% wood component and 60-90 wt% 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% by weight 200 to 330 mesh 20 to 40% by weight 330 mesh or less 40 to 70% by weight, and the average particle size is 20 to 40 μm.

In the present invention, a particle size of 75, in particular, containing 35 to 50% by weight of a wood component and 50 to 65% by weight of an inorganic component.
10 to 20% by weight of coarse powder having a particle size of from 300 μm to 300 μm
It is preferable to use a fine powder having a particle size of 5 μm or more and 45 μm or less, which contains a wood component and 80 to 90% by weight of an inorganic component.

In addition to the above raw materials, a part of the cement may be further replaced with a silicic acid-containing substance such as silica sand, silica stone powder, silica fume, blast furnace slag, fly ash, shirasu balloon, perlite, bentonite and diatomaceous earth. Or anhydrate or crystallized chloride such as calcium chloride, magnesium chloride, iron chloride, aluminum chloride, sodium chloride, potassium chloride, lithium chloride, aluminum sulfate, alum, iron sulfate, lithium sulfate, sodium sulfate, potassium sulfate , Anhydrate or crystallized product of sulfate such as magnesium sulfate, nitrate such as calcium nitrate, calcium nitrite, anhydride or crystallized product of nitrite, formate such as calcium formate, calcium acetate, anhydride or crystal of acetate Sulfide, sodium aluminate, water glass, etc. A curing agent, a water repellent such as wax, paraffin, or silicone, and expandable thermoplastic plastic beads such as expandable polystyrene beads may be added.

The wood cement board of the present invention has a three-layer structure in which front and back layers 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-layered wood cement board, the raw material mixture A for the front and back layers and the raw material mixture B for the core layer
The basic composition of the waste wood cement board other than the coarse powder and the fine powder is usually 30 to 70% by weight of cement, 5 to 35% by weight of wood reinforcing material, and the more preferable basic composition of the raw material mixture A for the front and back layers is cement 30. -60 wt%, silicic acid-containing substance 15-50 wt%, perlite 0-15 wt%, wood chips and / or wood flour 5-20 wt%, and the more preferable basic composition of the raw material mixture B for the core layer is Cement 30-
60% by weight, silicic acid-containing substance 15-50% by weight, perlite 0-15% by weight, wood fiber bundle 5-25% by weight, wood chips 0-10% by weight, expandable polystyrene beads 0.5-5
% By weight.

In addition to the basic composition, in the raw material mixture A for the front and back layers, wood powder having a particle size of 0.1 to 1.5 mm and a particle size of 45 μm to 1000 μm (average particle size 80 to 10)
3 to 20% by weight in total of the coarse powder of the secondary crushed wood cement board waste material, and in the raw material mixture B for the core layer, the particle size is 1 μm or more and 500 μm or less (average particle size 20 to 4).
Fine powder 7 of the wood cement board secondary pulverized scrap 0 .mu.m)
~ 40 wt% is added. The mixing ratio of the above wood powder and the coarse powder of the secondary crushed wood cement board waste material is 40: 60-
It is desirable to set it to 0: 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 inhibiting substance contained in the wood powder is increased and the cement hardening failure becomes remarkable. In the above-mentioned three-layer wood cement board, in order to give a dense structure to the raw material mixture A of the front and back layers, a fine reinforcing material such as wood chips having an opening of 4.5 mm or less is usually used as a wooden reinforcing material. And the raw material mixture B for the core layer
In order to give a rough structure, a coarse wood reinforcing material such as a wood piece having an opening of 4.5 mm to 10 mm or a wood fiber bundle having an average diameter of 1.0 mm and a length of 20 mm is usually used as a wood reinforcing material. Further, in the present invention, in place of a part of the fine powder and / or the coarse powder of the secondary crushed product of the wood cement board waste material, the primary crushed product is 0 to 2% by weight in the front and back layers and 0 in the core layer.
~ 28 wt% may be used.

As a method for producing the wood cement board of the present invention, it is desirable to adopt a dry production method in which the steps can be easily continued and the apparatus is simple. In step 1 of the dry manufacturing method, the raw material mixture A is sprinkled on the template in the form of a mat, the raw material mixture B is sprinkled on the mat in the form of a mat, and the raw material mixture A is further spread on the mat. And the raw material mixture A and the raw material mixture B
Water for 30 to 5 each for hardening reaction of cement.
0% by weight is added. Add wood chips to raw material mixture B,
When a wood fiber bundle that is made bulky by branching and / or bending and / or bending is used as the wood fiber bundle, the raw material mixture B is easily unraveled and easily spread evenly on the template.

In the continuous manufacturing method, a large number of the templates are placed on a belt conveyor. If desired, the raw material mixture scattered on the template is slightly pressed by a roll or the like to form a mat, and the mat is then pre-cured under pressure in the presence of water in step 2 to be molded into a desired shape.

Clamping conditions are usually a clamping pressure of 1.0 to 3.0M
Pa, temperature 60 to 80 ° C., time 6 to 20 hours, heating is usually performed by steam. The pressing is performed by sandwiching the mat between two mold plates, but the mold plate surface may be provided with a predetermined shape, an uneven pattern or the like. The pre-cured product obtained by the compression pre-curing in the above step 2 is cured in an autoclave in step 3.

The curing condition is usually a pressure of 0.6 to 2.0MP
a, 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 silicic acid-containing substance is completely performed by the autoclave curing, and when the expandable thermoplastic beads are added to the core layer, the expandable thermoplastic beads are completely expanded. Then, the plastic foam particles formed by the foaming of the expandable thermoplastic beads are melted and the foaming agent in the cells escapes to the outside, and the plastic foam particles rapidly shrink and a large number are inside the core layer. Holes are formed. Then, a thermoplastic coating layer based on the plastic foam particles is formed on the inner wall surface of the pores.

Further, in step 3, for example, curing may be performed at room temperature of 25 ° C. for 4 to 10 days. However, in this case, it is desirable to lower the compounding ratio of the silicic acid-containing substance and increase the cement content. The wood cement board of the present invention is produced in this manner. 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]

[Operation] When the wood cement board waste material is crushed by the impact type crusher, the crushed product (1) as shown in FIG. 1 has a particle size of 0.5 to 2.0 mm, and the cement hardened product (2 ),
It has unreacted cement content (3) inside. When such a pulverized product (1) is further pulverized by a grinding pulverizer, a 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. Unreacted cement content
(3) will be exposed to the outside. Therefore, such a secondary pulverized product (1A) has high reactivity and causes a hardening reaction together with cement in the wood cement board . Particularly in the present invention, the secondary pulverized product (1A) is further flattened with a particle size of 45 μm or more and 1000 μm or less, preferably 75 μm or more and 1000 μm or less .
Coarse powder with a uniform particle size of 80 to 100 μm and particle size of 1 μm or more 50
Average of 0 μm or less, preferably 1 μm or more and less than 75 μm
Since a coarse powder containing a large amount of wood components is classified into fine powder having a particle size of 20 to 40 μm , the wood reinforcing material for the front and back layers can be saved accordingly. Especially in the present invention, the wood powder is replaced by the above-mentioned coarse powder, but the wood reinforcing material in the waste material of the wood cement board is heated to some extent during the production of the wood cement board, and the cement hardening inhibiting substance is eluted to some extent. Since there is almost no elution amount of the cement hardening inhibiting substance from the coarse powder, defective cement hardening can be prevented. As described above, the particle size of the wood powder used for the front and back layers is 1.0 mm on average, but 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. To improve rather than hindering.

On the other hand, fine powder is added to the core layer, but since it has higher reactivity than the above coarse powder, it causes a favorable hardening reaction together with cement. Almost 60% of the cement component of the wood cement board remains as an unreacted material immediately after the production,
The unreacted material is filled in the pores of the hardened cement matrix. Thus, when the unreacted material is filled in the cement hardened material matrix pores, the dimensional stability of the wood cement board is deteriorated. In the present invention, the fine powder is also filled in the pores of the cement hardened material matrix in the core layer, and since the hardened cement contains the hardened cement after the reaction in addition to the unreacted cement, it is filled as an aggregate. It is effective, and it becomes difficult for water and the like to enter the pores, and shrinkage and swelling are suppressed. Further, since it reacts with unreacted substances remaining in the wood cement board in the pores to some extent, the dimensional stability of the wood cement board is greatly improved.

When a wood cement board waste material having a three-layer structure as in the present invention is used, the front and back layers also contain the components used in the core layer, for example, wood fiber bundles.
The compositions of the front and back layers and the core layer tend to be close to each other, the difference in physical properties between the front and back layers and the core layer is reduced, and the interlayer peel 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 powder,
If you replace it with a flat-shaped piece of wood, the structure will be uniform, and you can replace part of the cement or silicic acid-containing substance.
Entanglement with the wood reinforcing material is stronger than that of fine powder such as cement, and the strength of the board is improved.

[0023]

EXAMPLE 40 to 50 water was added to the mixture having the composition shown in Table 1.
Samples 1, 2, 3, 4, 5, 6, 7 of the present invention, which are wood cement boards having a three-layer structure having front and back layers and a core layer, were prepared using a water-mixture added in an amount of 1% by weight (Example 1). ~ 7) and Comparative Sample 1 (Comparative Example 1) were prepared by the dry method.

Samples and comparative samples were placed on the lower template in Table 1.
A predetermined amount of the mixture of the surface layer composition shown in Table 1 is sprayed to form a surface layer mat, and a predetermined amount of the mixture of the core layer composition shown in Table 1 is sprayed onto the core layer to form a core layer mat. A predetermined amount of the mixture of the above composition of the surface layer is sprayed to form a back layer mat, and an upper mold plate is brought into contact therewith, and press-pressing, curing, curing and drying are carried out under the conditions shown in Table 1, thereby forming a three-layer structure. Then, a wood cement board sample with a weight ratio of front / back layers / core layer = 1/3 was 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 front and back layers have a particle size of 0.1.
0 ~ 5% by weight of wood powder in the range of ~ 1.5mm and particle size 45μm
More than 1000 μm or less (average particle size 80 to 100 μm ) of wood cement board waste wood coarse powder is contained in an amount in the range of 3 to 20% by weight, and the core layer has a particle size of 1 μm or more and 500 μm or less ( Samples 1, 2, 3, 4, 5, 6, 7 of the present invention (Examples 1 to 7) in which the wood cement board waste wood fine powder ( average particle size 20 to 40 μm) is contained in an amount of 40% by weight or less are Strength and dimensional stability as compared with Comparative Sample 1 (Comparative Example 1) in which about 1% by weight of front and back layers and about 27% by weight of core layer were added pulverized wood cement board waste material having a particle size of 0.5 to 2.0 mm Has improved.

[0028]

EFFECTS OF THE INVENTION In the present invention, in addition to the addition of a crushed product of a wood cement board waste material by an impact crusher, the crushed product is secondarily crushed by a grinding crusher 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, and the surface has sharp irregularities. It is possible to provide a wood cement board having a pattern and having a high design property.

[Brief description of drawings]

FIG. 1 is an explanatory view of a primary crushed product by a conventional impact type crusher.

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

[Explanation of symbols]

1 Primary crushed product 1A Secondary ground product

Continuation of front page (51) Int.Cl. ⁷ Identification code FI // (C04B 28/02 C04B 28/02 18:16 18:16 16:02 16:02 Z 14:06 14:06 Z 18:08 18 : 08 Z 16:08) 16:08 (56) Reference JP-A-6-293548 (JP, A) JP-A-10-245254 (JP, A) JP-A-9-286657 (JP, A) JP Hei 7-124927 (JP, A) JP 2001-130941 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C04B 18/16

Claims (5)

(57) [Claims] 1. Cement 30 to 60% by weight, silicic acid-containing substance 15 to 50% by weight, pearlite 0 to 15% by weight, wood chips and / or wood powder 5-2 having an opening of 4.5 mm or less.
0% by weight, grain size 0.1-1.5 mm wood flour , grain size 45μ
m to 1000 μm and average particle size 80 to 100 μ
m wood cement board waste wood rough powder, front and back layers consisting of a cured product of a mixture containing a total of 3 to 20% by weight, and cement 3
0-60% by weight, silicic acid-containing substance 15-50% by weight, perlite 0-15% by weight, wood fiber bundle 5-25% by weight,
0 to 10% by weight of wood chips with an opening of 4.5 mm to 10 mm,
Expandable polystyrene beads 0.5-5% by weight, particle size 1μ
wood cement board having a three-layer structure consisting of a core layer made of a cured product of a mixture containing 7 to 40% by weight of fine powder of waste wood waste wood cement board having an average particle size of 20 m to 500 m and an average particle size of 20 to 40 m. 2. The coarse powder and fine powder of the waste wood cement board waste material are primarily crushed by an impact type crusher, and the primary crushed material is secondarily crushed by a grinding crusher, and the secondary powder The wood cement board according to claim 1, which is obtained by classifying a pulverized product. 3. A wood component in the coarse powder of the wood cement board waste material.
25 to 50 % by weight of the wood cement board waste wood fine powder
Claim that the powder contains 60 to 90% by weight of inorganic components
Item 3. The wood cement board according to item 1 or 2. 4. The wood cement board is a waste of the wood cement board.
Instead of part of the coarse powder and / or fine powder, wood
A primary crushed product of a ment plate waste material is added .
Wood cement board described in 3. 5. The wood cement board and wood cement board waste
The wood contains a wood fiber bundle as a wood reinforcement and
Woody cell according to claim 1-4 are those prepared me
Ment plate