JP2910899B2 - Manufacturing method of plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a plywood, a medium-density fiberboard and a particle board which can be used as a material for building and furniture.

[0002]

2. Description of the Related Art Conventionally, plywood has been widely used as a building material and a furniture material. However, from the viewpoint of environmental protection, the cutting of forests (particularly, tropical rainforests) is suppressed. This makes it difficult to obtain wood for plywood, which may lead to higher prices. For this reason, particleboard and medium-density fiberboard, which are mainly made of plywood, sawn wood, and the like, are used as alternatives to plywood.

However, the particle board has a specific gravity of 0.73 to 0.78, which is higher than that of plywood, and has a flexural strength of 180 to 250 kgf / c, which is about 1/3 that of plywood.
m ² . Further, the particle board has a thickness expansion coefficient of 4 to 5 times that of plywood when absorbing water, and a moisture absorption linear expansion coefficient of about 2 times that of plywood.

On the other hand, the medium specific gravity fiberboard has a specific gravity substantially equal to that of the plywood, but has a flexural strength of 350 to 400 kgf / cm ² corresponding to 60 to 70% of the plywood. The medium specific gravity fiberboard has a thickness expansion coefficient of about twice that of plywood when absorbing water, and has a moisture absorption linear expansion coefficient of 2 to 4 times that of plywood.

[0005] For this reason, in any case, since the thickness expansion coefficient and the hygroscopic linear expansion coefficient at the time of water absorption are larger than those of the plywood, the plywood swells, warps, and has gaps due to water wetting and subsequent drying. Is liable to occur.

[0006] In view of the above problems, the present invention provides a plate-like body which has a thickness expansion coefficient and a water absorption linear expansion coefficient at the time of water absorption equal to or less than that of plywood, and can be replaced with plywood, particle board or medium density fiberboard. It is intended to provide a manufacturing method.

[0007]

According to the present invention, there is provided a method for manufacturing a plate-like body, comprising the steps of:
-60% by weight, organic fiber 5% by weight or more, inorganic powder 20
A slurry composed of a binder of up to 60% by weight and a binder is formed into an upper and lower layer of a wet inorganic mat, and the lower layer wet inorganic mat is combined with 60 to 90% by weight of an inorganic foam and at least 5% by weight of organic fibers. After spraying and depositing a mixture for the middle layer mixed with the agent under spray water, the upper layer wet inorganic mat is disposed, and the laminate is heated and compressed by a high-temperature continuous press, and then dried, and the upper and lower layers are dried. It is a plate-like body having a specific gravity of 0.9 or more, a specific gravity of the intermediate layer of 0.4 to 0.7, an overall specific gravity of 0.6 to 0.8, and a total bending strength of 180 kgf / cm ² or more. This is a method for producing a plate-like body.

The mineral fiber forming the outer layer portion is added to obtain a desired bending strength and to suppress a thickness expansion coefficient and a moisture expansion coefficient at the time of water absorption. Slag wool, mineral wool, glass fiber and the like can be mentioned, and these can be used alone or in combination of two or more kinds. The composition ratio of the mineral fibers in the outer layer is preferably 20 to 60% by weight. When the content is 20% by weight or less, the bending strength is low, and the surface is easily broken at the time of screwing. When the content is 60% by weight or more, the addition amount of the inorganic powder is relatively low, and the surface hardness is low. Also, the screwing performance cannot be increased.

The organic fibers forming the outer layer are added to improve the bending strength, and examples thereof include pulp and the like in addition to synthetic resin fibers such as polypropylene fibers. Or in combination of two or more. The composition ratio of the organic fibers in the outer layer is preferably at least 5% by weight.
If the content is less than 5% by weight, the strength is not increased because the fibers are brittle even when the proportion of the mineral fibers is increased.

The inorganic powder forming the outer layer is used to increase the hardness and the screwing performance while maintaining the fire resistance. For example, calcium carbonate, silica sand, microsilica, slag, hydroxide Aluminum and wollastonite can be exemplified. The composition ratio of the inorganic powder in the outer layer is preferably 20 to 60% by weight. If the content is less than 20% by weight, the desired surface hardness cannot be obtained. If the content is more than 60% by weight, the ratio of the mineral fibers relatively decreases, so that the desired strength cannot be obtained. . The strength of the outer layer portion is greatest when an inorganic powder having a particle size of about 150 μm is used, but the inorganic powder may have an average particle size of 40 μm to 300 μm.

The binder forming the outer layer is for linking and integrating the mineral fibers, organic fibers and inorganic powder, and is, for example, a synthetic resin such as polyvinyl alcohol resin or phenol resin, starch or the like. And these can be used alone or in combination of two or more. However, a small amount of starch can increase the bending strength, but since it alone reduces the adhesive strength when wet, it is preferable to use a phenol resin, an acrylic resin, or the like in combination.

Generally, the more the organic fibers and the binder, the more effective in terms of strength. It is also preferable to use a fusible fiber which serves both as a fibrous material and a binder in order to improve strength and the like.

Further, the specific gravity of the outer layer portion is preferably 0.9 or more for the following reason. That is, when the ratio of the inorganic powdery material is, for example, 40% by weight and the outer layer portion is formed, there is a correlation between the specific gravity of the outer layer portion and the surface hardness, and between the specific gravity and the bending strength. Yes, the surface hardness and bending strength increase as the specific gravity increases. Then, in practical use, in order to obtain an outer layer having substantially the same surface hardness and bending strength as the particle board, it is necessary that the specific gravity of the outer layer be 0.9 or more. Further, when the specific gravity is less than 0.9, a dense outer layer portion cannot be obtained, the amount of water absorption increases, and desired water resistance or the like cannot be obtained.

The inorganic foam forming the middle layer is for reducing the weight while maintaining the compressive strength, and includes, for example, pearlite, shirasu foam, silica flower, glass foam and the like. Alternatively, two or more kinds can be used in combination. The composition ratio of the inorganic foam in the middle layer is preferably set to 60 to 90% by weight. 6
When the content is less than 0% by weight, the binder added to form the middle layer portion and other proportions are relatively increased, so that the strength is improved, but the effect of lowering the specific gravity is not obtained. If the content exceeds 90% by weight, the ratio of the binder or the fiber decreases, and it becomes difficult to improve the overall strength.

The organic fibers forming the middle layer are added to connect the inorganic foams to each other to improve the strength. The material and amount of the organic fibers forming the middle layer are as described above. The description is omitted because it is the same as the case of the outer layer portion, but it is preferable to add at least 5% by weight or more. That is, when the addition amount is less than 5% by weight, the inorganic foam is mainly connected by the binder, so that it is brittle and easily broken.

The binder forming the middle layer is added to connect the inorganic foam and the organic fiber. The material and amount of the binder are the same as those in the outer layer described above. Although the description is omitted, it is not always necessary to add the same material in the same amount, and a different material can be used in an appropriate amount. Although it is possible to use a fusible fiber as a binder, when it is used in either the outer layer or the middle layer, the effect is greater when used in the middle layer.

Further, the specific gravity of the middle layer is preferably set to 0.4 to 0.5. This is because, in order to obtain a plate-like body as a substitute for a particle board having a thickness of 12 to 20 mm, the specific gravity of the upper and lower layers needs to be 0.9 or more in order to secure a desired bending strength. is there. If a three-layer plate is to be formed by pressing once, it is necessary to apply a large press pressure to increase the specific gravity of the upper and lower layers, which inevitably increases the specific gravity of the middle layer. Increase
This is because the specific gravity of the middle layer is set to 0.4 to 0.5.

Further, the specific gravity of the middle layer may be 0.5 to 0.6. In order to obtain a plate-like body as an alternative to the medium specific gravity fiberboard, it is necessary to increase the specific gravity of the upper and lower layers by press compression to 1.0 or more, and this press compression necessarily involves the specific gravity of the intermediate layer. Is set to 0.5 to 0.6.

The specific gravity of the middle layer may be set to 0.6 to 0.7 by press-clamping the specific gravity of the upper and lower layers to 1.0 or more. In this case, it is possible to obtain a bending strength and a bending Young's modulus comparable to plywood depending on the type and amount of the organic fiber and the amount of the binder.

By setting the specific gravity of the upper and lower layers to 0.9 or more as described above, the corresponding plate-like body is almost determined by the specific gravity of the middle layer. That is, the specific gravity of the middle part is 0.4 to 0.5.
In the case of (1), it has a performance that can be replaced by a particle board, in the case of 0.5 to 0.6, it can be replaced by a medium specific gravity fiberboard, and in the case of 0.6 to 0.7, it can be replaced by a plywood.

The plywood and the medium-density fiberboard are both 3 mm
Thicknesses larger than about the thickness are commercially available, but the product of the present invention has a large specific gravity of the upper and lower layers, and if the middle layer is not formed, the specific gravity becomes too large. It is the lower limit.

Next, a method of manufacturing a plate-like body according to the present embodiment will be described. For example, mineral fiber, organic fiber, inorganic powder and binder are suspended in water to obtain an aqueous slurry, which is wet-processed to obtain a wet inorganic mat to be a lower layer and an upper layer (outer layer). .

On the other hand, an inorganic foam, an organic fiber and a binder are mixed to obtain a mixture for the middle layer, and the mixture is wet-processed, and the mixture is uniformly dispersed and deposited on the surface of the above-mentioned wet inorganic mat to be a lower layer. To form a middle layer portion, and the wet inorganic mat as the upper layer portion is laminated thereon to obtain a laminate.

Then, when the laminate is pressed with a press, the air in the middle layer is extruded and reaches a certain density, then the density of the upper and lower layers increases, and the specific gravity of the upper and lower layers becomes 0.7.
Reaches ~ 0.8. Further, when pressure is applied, a part of the inorganic foam in the middle layer part bites into the upper and lower layers, and the thin portion of the inorganic foam is destroyed to increase the density of the middle layer. By increasing the pressure to 9 or more, and further increasing the pressure, the density of the middle layer increases. When heated in this state, steam generated from the upper and lower layers flows into the middle layer, which activates the binder in the middle layer and integrates the whole.

From the viewpoint of productivity, it is not advisable to perform drying with a continuous press.
Drying with a dryer is preferred. In the above-described manufacturing method, a manufacturing method combining a dry method and a wet method has been described. However, all manufacturing methods may be performed by a dry method or all methods may be performed by a wet method, and an arbitrary manufacturing method can be selected.

[0026]

Next, an embodiment according to the present invention will be described. (Example 1) 30 parts by weight of rock wool, 20 parts by weight of pulp, 25 parts by weight of calcium carbonate, 5 parts by weight of starch, 20 parts by weight of powdered phenol, and a small amount of a fixing agent were put into clear water.
An aqueous slurry having a concentration of 2% was obtained by stirring, and the slurry was introduced into a fourdrinier machine to form a paper, thereby obtaining a wet inorganic mat having a lower layer portion and an upper layer portion having a thickness of 5.0 mm.

On the other hand, 65 parts by weight of pearlite, 10 parts by weight of pulp, 15 parts by weight of starch, and 10 parts by weight of powdered phenol as inorganic foam were mixed with 100 parts of these solid components.
The mixture was mixed with water at a rate of 30 to obtain a mixture for the middle layer.

Then, the mixture for the middle layer is evenly spread and deposited on the wet inorganic mat to be the lower layer so as to have a thickness of 30 mm, and the wet inorganic mat to be the upper layer is disposed thereon. A laminate having a thickness of 40 mm was obtained. Then, the laminate was pressed by a continuous press at a temperature of 180 ° C. and a pressure of 12 kg / cm ² to be pressed to a total thickness of 9 mm.
The plate was dried in a drying oven at a temperature of 180 ° C. for 20 minutes, and further cut into an appropriate length to obtain a plate-like body, which was used as a sample. The specific gravity of the upper and lower layers of the obtained sample was 1.0.
The specific gravity of the middle part was 0.73, and the overall specific gravity was 0.77.

Comparative Example 1 A commercially available plywood (9 mm thick type II plywood) was used as a sample.

(Example 2) 40 parts by weight of rock wool, 10 parts by weight of pulp, 30 parts by weight of calcium carbonate, 10 parts by weight of starch, 10 parts by weight of powdered phenol, and a small amount of a fixing agent were put into clear water and stirred. Thus, an aqueous slurry having a concentration of 2% was obtained, and this was guided to a fourdrinier paper machine to form a paper, thereby obtaining a wet inorganic mat having a lower layer portion and an upper layer portion having a thickness of 5.5 mm.

On the other hand, 65 parts by weight of pearlite, 10 parts by weight of pulp, 15 parts by weight of starch, and 10 parts by weight of powdered phenol as inorganic foam were mixed with 100 parts of these solid components.
The mixture was mixed with water at a rate of 30 to obtain a mixture for the middle layer.

Then, the mixture for the middle layer is uniformly spread and deposited on the wet inorganic mat to be the lower layer so as to have a thickness of 36 mm, and the wet inorganic mat to be the upper layer is disposed thereon. A laminate having a thickness of 47 mm was obtained. Then, the laminate is pressed by a continuous press at a temperature of 180 ° C. and a pressure of 10 kg / cm ² to be pressed to a thickness of 15 mm, and then dried in a drying furnace at a temperature of 180 ° C. for 20 minutes. The plate was cut into a length to obtain a sample, which was used as a sample.
The specific gravity of the upper and lower layers of the sample was 0.9, the specific gravity of the middle layer was 0.52, and the overall specific gravity was 0.65.

Comparative Example 2 A commercially available particle board (P-150) was used as a sample.

Example 3 40 parts by weight of rock wool, 15 parts by weight of pulp, 25 parts by weight of calcium carbonate, 5 parts by weight of starch, 15 parts by weight of powdered phenol, and a small amount of a fixing agent were put into clear water.
An aqueous slurry having a concentration of 2% was obtained by stirring, and the slurry was introduced into a fourdrinier machine to form a paper, thereby obtaining a wet inorganic mat having a lower layer portion and an upper layer portion having a thickness of 5.0 mm.

On the other hand, 65 parts by weight of pearlite, 10 parts by weight of pulp, 5 parts by weight of starch, and
20 parts by weight of powdered phenol were mixed with 100 of these solids under spraying of water at a ratio of 30 to obtain a mixture for the middle layer.

Then, the mixture for the middle layer is uniformly spread and deposited on the wet inorganic mat to be the lower layer so as to have a thickness of 25 mm, and the wet inorganic mat to be the upper layer is disposed thereon. A laminate having a thickness of 35 mm was obtained. Then, the laminate was pressed with a continuous press at a temperature of 180 ° C. and a pressure of 10 kg / cm ² to be pressed to a thickness of 9 mm, and then dried in a drying furnace at a temperature of 180 ° C. for 20 minutes. The plate was cut into a length to obtain a sample, which was used as a sample. The specific gravity of the upper and lower layers of the sample was 0.95, the specific gravity of the middle layer was 0.53, and the overall specific gravity was 0.67.

(Comparative Example 3) Commercially available medium-density fiberboard with a thickness of 9 mm (MDF-L type)
Was used as a sample.

Next, Table 1 shows the measurement results of the physical properties of Examples 1 to 3 and Comparative Examples 1 to 3.

[Table 1]

The above measurement results were obtained based on the following method. Flexural strength: based on JIS A 5907-1977. Bending Young's modulus: Based on JIS Z 2113-63. JAS2 flexural strength: After wetting and drying according to the wetting method for JAS special plywood, the flexural strength was measured according to JIS A 5907. JAS2 thickness expansion coefficient: After wetting and drying according to the wet method for JAS special plywood, the thickness expansion coefficient was measured according to JIS A 5908.
Measured by -93. Hygroscopic linear expansion coefficient: It was performed in accordance with JIS A 5403. Wood screw holding power: Based on JIS A 5908. Nail head penetration: Based on JIS A 5910.

As is clear from the above measurement results, when Example 1 is compared with Comparative Example 1 (plywood), Example 1 has a higher density, flexural strength, flexural Young's modulus, and JAS2 flexural strength. Although slightly inferior to Example 1, this is a difference that does not pose a problem in practical use. Further, Example 1 is superior to Comparative Example 1 in terms of JAS2 thickness expansion coefficient, moisture absorption linear expansion coefficient, or peel strength, which indicates characteristics at the time of water absorption.
It was found that a plate having better water resistance than plywood could be obtained. Furthermore, although the Example 1 is inferior to the Comparative Example 1 in the wood screw holding force and the nail head penetration force, the former has almost the same performance as the particle board of the Comparative Example 2, so that there is a practical problem. According to the latter, it is considered that although it is practically subject to certain restrictions, it can be sufficiently used. Therefore, according to the first embodiment,
It was found that a plate-like body that could replace plywood was obtained.

When comparing Example 2 with Comparative Example 2 (particle board), Example 2 is slightly inferior to Comparative Example 2 in bending Young's modulus, but this is a difference that does not pose a problem in practical use. It is. Further, Example 2 is superior to Comparative Example 2 in density, bending strength and peel strength. In particular, JAS2 flexural strength, which indicates characteristics when absorbing water, JA
Example 2 is much better than Comparative Example 2 in S2 thickness expansion coefficient and moisture absorption linear expansion coefficient. Although Example 2 was inferior to Comparative Example 2 in wood screw holding force and nail head penetration force, the former was considered to be a practically negligible difference. In addition, although it is subject to certain restrictions, it is considered to be a value that can be sufficiently used. Therefore, according to Example 2, it was found that a plate-like body that could be substituted for the particle board was obtained.

When comparing Example 3 with Comparative Example 3 (medium specific gravity fiberboard), Example 3 is slightly inferior in density to Comparative Example 3, but with a difference that is considered to be almost equal. is there. On the other hand, the JAS2 bending strength, the JAS2 thickness expansion coefficient, which indicates the bending strength, the bending Young's modulus, and the characteristics at the time of water absorption,
Example 3 is far superior to Comparative Example 3 in the coefficient of linear hygroscopic expansion or peel strength. In addition, although Example 3 was slightly inferior to Comparative Example 3 in the wood screw holding force and nail head penetration force, the difference in the former case was on the order of not causing a problem in practical use. In addition, although it is subject to certain restrictions, it is considered that it can sufficiently withstand use. Therefore, according to Example 3, it was found that a plate-like body that could be replaced with a medium-density fiberboard was obtained.

From the above measurement results, according to the plate-like bodies of Examples 1, 2, and 3, the plywoods of Comparative Examples 1, 2, and 3
It was found that alternatives with better water resistance and moisture resistance than particle board and medium density fiberboard could be obtained.

[0044]

As is apparent from the above description, according to the present invention, by appropriately selecting the material and the manufacturing conditions,
It has almost the same performance as plywood, particle board, and medium-density fiberboard. In particular, a plate-like body with little deterioration in water absorption can be obtained. The body is obtained. In the case of a plate-like body, a laminate in which the middle layer is disposed between the upper and lower layers is pressed by a continuous press. However, since the pressing is performed at a high temperature, the moisture (steam) of the upper and lower layers is transferred to the middle layer during the heating and compression. To activate the binder in each layer. That is, since the binder hardens to such an extent that the upper and lower layer portions made of fibers do not cause springback, a plate-like body having a predetermined thickness can be easily obtained. Furthermore, a plywood, a particle board, and a medium-density fiberboard can be manufactured with a set of equipment simply by appropriately selecting the material and the manufacturing conditions, so that the degree of freedom in manufacturing is increased.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) E04C 2/24 E04C 2/20 B32B 1/00-35/00

Claims (1)

(57) [Claims] 1. A slurry comprising 20 to 60% by weight of a mineral fiber, 5% by weight or more of an organic fiber, 20 to 60% by weight of an inorganic powdery material and a binder to form a wet inorganic mat as an upper and lower layer. After the lower layer wet inorganic mat is sprayed and deposited with a middle layer mixture obtained by mixing 60 to 90% by weight of an inorganic foam, 5% by weight or more of an organic fiber and a binder under spray water, and depositing the mixture, the upper layer is wetted. An inorganic mat is arranged, and the laminate is heated and compressed by a high-temperature continuous press, and then dried. The specific gravity of the upper and lower layers is 0.9 or more, and the specific gravity of the intermediate layer is 0.4 to 0.7.
The overall specific gravity is 0.6-0.8 and the overall bending strength is 180kg
A method for producing a plate-like body, wherein the plate-like body has an f / cm ² or more.