JPH0569785B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an inorganic molded body made of a mixture of wood fiber bundles and curable inorganic powder, and a method for producing the same. [Prior Art] Inorganic molded bodies mainly composed of curable inorganic powder such as cement are used as architectural board materials such as exterior wall materials, interior wall materials, roofing materials, and the like. This type of inorganic molded body includes a wood chip cement board in which wood chips are mixed as a reinforcing material (Special Publication Publication No. 39-1981).
No. 12950). A wood chip is a shaving of wood, usually of length
It has a flake shape of about 20 to 50 mm, width of 1.0 to 6.0 mm, and thickness of about 0.1 to 1.0 mm, and is placed in the inorganic molded body and acts as a binder and gives flexibility to the inorganic molded body, It is also lightweight. [Problem to be solved by the invention] However, when wood pieces are used as reinforcing material,
Intertwining of the wood pieces with each other is hardly expected, and therefore the reinforcing effect is not sufficient. Therefore, sufficient strength cannot be obtained unless the compacting force during molding is increased to increase the density of the product. However, increasing the density of the product makes it heavier, making it difficult to carry and nail. In order to obtain sufficient strength without increasing the density of the product, it is necessary to increase the amount of wood chips added. However, there was a problem in that if the amount of wood chips added was increased, the nonflammability of the product would decrease. Inorganic molded bodies mixed with pulp fibers, which are more easily entangled in shape than wood chips, are also available as reinforcing materials, but the reinforcing effect of pulp fibers is not sufficient, and it is necessary to mix asbestos or synthetic fibers ( JP-A-63-256560, JP-A-63-256561, JP-A-56
−63858). However, even if asbestos or synthetic fibers are mixed with pulp fibers, these fibers are not bulky, so in order to obtain a product that is lightweight and has satisfactory strength, it is still necessary to add a large amount of fiber. However, increasing the amount of these fibers added increases the material cost, and increasing the amount of pulp fibers or synthetic fibers decreases the nonflammability of the product. Although asbestos is nonflammable, it is easily dispersed into the air and has severe restrictions on its use as a harmful substance to the human body. In addition, as an efficient method for producing this type of inorganic molded body, a dry manufacturing method is used in which a mixture of curable inorganic powder and reinforcing material is sprinkled on a template to form a mat, and the mat is pressed and formed. Recommended. In this dry manufacturing method, it is necessary that the mixture of the curable inorganic powder and reinforcing material be easily spread evenly on the template, and that the mat formed on the template be difficult to lose its shape. However, when using wood pieces as reinforcing materials, there is almost no entanglement as mentioned above,
If the amount of wood chips added is not increased, the pine formed on the template will easily lose its shape, and if pulp fiber or a mixed fiber of pulp fiber mixed with asbestos or synthetic fiber is used as a reinforcing material, it will harden. When mixed with a synthetic inorganic powder, the mixture becomes entangled in a ball-like form, making it difficult to unravel the mixture, making it extremely difficult to spread it uniformly on the template. [Means for Solving the Problems] The present invention provides a means for solving the above-mentioned conventional problems, in which the average diameter is 0.1 to 2.0 mm and the average length is 10 to 30 mm.
A mixture of wood fiber bundles and curable inorganic powder, which are in the range of An inorganic molded body made of hardened powder is provided, and the inorganic molded body is made by uniformly scattering a mixture of the wood fiber bundle and the curable inorganic powder on a template to form a mat;
After pressing the mat and hardening it in the presence of moisture,
Manufactured by autoclave curing. The present invention is characterized in that a wood fiber bundle is used as a reinforcing material. In the present invention, the wood fiber bundle is a bundle of wood single fibers, and the wood fiber bundle is made bulky by branching and/or curving and/or bending. To produce wood fiber bundles made bulky by branching and/or curving and/or bending, wood is immersed in a chemical solution such as caustic soda, sodium sulfite, calcium sulfite, etc., or the wood is heated with steam. By heating, or by using the above-mentioned chemical immersion and steam heating in combination, the lignin, hemicellulose, resin, etc. that act as binders for the wood fibers contained in the wood are not completely dissolved. It is a pulp fiber that is only swollen and then defibrated with the binder remaining, and has a larger diameter than pulp fiber that is defibrated after almost completely removing the binder, especially lignin. The average diameter of the wood fiber bundles is approximately 0.1
~2.0 mm, with average lengths ranging from approximately 10 to 30 mm. If the wood fiber bundle is branched, the average diameter of the wood fiber bundle before branching is approximately 0.1 to 2.0.
mm range, and the wood fiber bundles are curved and/or
Or, if the wood fiber bundle is bent, the length refers to the actual length of the wood fiber bundle, not the distance between the ends. The wood fiber bundle is bulky due to the above size and shape, and its bulk specific gravity is approximately 0.03 to 0.05.
g/cm ³ range. Here, the bulk specific gravity is 8 cm in inner diameter,
Fill a measuring cylinder with a volume of 2000ml with 2000ml of the wood fiber bundle in an absolutely dry state, measure the total weight, subtract the weight of the graduated cylinder from the total weight to determine the weight of the wood fiber bundle, A disk that fits exactly within the inner diameter of the wood fiber bundle is placed on the filled wood fiber bundle, a weight is placed on the disk, and a weight of 1 kg is applied to the wood fiber bundle, and the volume of the wood fiber bundle is measured. , is determined by dividing the weight (g) of the wood fiber bundle by the volume (cm ³ ). In order to make the wood fiber bundle bulky by branching and/or curving and/or bending, the degree of swelling and fibrillation of the binder are adjusted. Defibration is performed, for example, by a grinding disk, and the degree of defibration is adjusted by adjusting the disc gap of the grinding disk. The curable inorganic powder used in the present invention is an inorganic powder that hardens through a hydration reaction of cement, gypsum, etc.
Mixed inorganic powders that harden through calcium silicate reactions, such as mixtures of calcium-containing inorganic powders such as cement and gypsum, and silicic acid-containing inorganic powders such as silica sand, silica powder, silica fume, and shirasu balloons, and crystal dislocation in magnesium carbonate, etc. It is an inorganic powder etc. that is hardened by The wood fiber bundles and the curable inorganic powder are mixed, and in the case of a dry manufacturing method, the mixture is sprinkled on a template. % is added. Furthermore, perlite, bentonite, blast furnace slag,
Inorganic fillers such as rice ash, fly ash, and diatomaceous earth, which are incinerated ash of rice husks, and organic fillers such as synthetic resins, synthetic resin foams, wood chips, and wood flour may be added. Further, when the curable inorganic powder is cement, a curing accelerator such as magnesium chloride, calcium chloride, aluminum sulfate, water glass, etc. may be added. The above examples are not intended to limit the invention. The above-mentioned mixture is spread onto a mold plate to form a mat, and in a continuous production method, a large number of the above-mentioned mold plates are placed on a belt conveyor. The mixture spread on the template is pressed slightly, if desired, with rolls or the like, and the mat is then compacted and hardened in the presence of moisture to form the desired shape. The amount of water added is usually 30 to 45% by weight in the above mixture. The pressing conditions are usually a pressing pressure of 10 to 20 kg/cm ² ,
Heating is carried out at a temperature of 60 to 80°C for about 20 to 30 hours, and heating is usually done with steam. The pressing is performed by pressing the mat between two templates, but the template surface may be provided with a predetermined shape, uneven pattern, etc. The inorganic molded article of the present invention is usually molded into a plate shape, but may be molded into a block shape or the like if desired. After the inorganic molding of the present invention is pressed and hardened, it is cured in an autoclave if desired. The curing conditions are usually pressure 10~20Kg/cm ² , temperature 160~180℃, time 5~10
It's time. The autoclave curing described above is not necessarily essential, and natural curing may be performed. In this way, the inorganic molded article of the present invention is obtained. [Function] The wood fiber bundles used in the inorganic molded article of the present invention have an average diameter of 0.1 to 2.0 mm, an average length of 10 to 30 mm, and have branched and/or curved and/or
Alternatively, since the fiber bundles are made bulky by bending, when mixed with the curable inorganic powder, the fiber bundles intertwine with each other at a certain distance,
Since the fiber bundles have a larger warp than pulp fibers, they have a certain degree of rigidity and do not become entangled in the form of threads, and in this way, the curable inorganic powder is spread between the entangled fiber bundles. being embraced. The above-mentioned rigidity of the fiber bundles helps maintain the distance between the fiber bundles and maintain the bulk. Therefore, when a dry manufacturing method is applied to the production of the inorganic molded body of the present invention, the mixture of the curable inorganic powder and the wood fiber bundle can be loosened by mechanical stirring, etc., and the mixture can be molded into a mold. It is easy to spread uniformly on the board, and on the other hand, as mentioned above, the curable inorganic powder is entangled due to the entanglement of the wood fiber bundles over a certain distance, so that it does not lose its shape. It is possible to form pine trees that do not grow. In the product, the wood fiber bundles in the matrix have a unique reinforcing effect in which the fiber bundles are tightly intertwined with each other at a certain distance as described above, and as a result, the wood fiber bundles are made of inorganic materials that have a low specific gravity and are therefore lightweight and have high strength. It gives a molded body. Further, in the production of the inorganic molded body of the present invention, autoclave curing is performed after pressing, and the curing reaction of the curable inorganic powder is almost completely completed during the autoclave curing. Therefore, the curing reaction of the curable inorganic powder hardly progresses in the product, and dimensional changes in the product due to the curing reaction are avoided. [Effects of the Invention] Therefore, in the present invention, an inorganic molded body that is lightweight, has high strength, and has extremely good dimensional stability can be obtained, and the inorganic molded body can be manufactured by a dry manufacturing method. It is easy to obtain a homogeneous product by this dry manufacturing method. Further, since the wood fiber bundle of the present invention has a large reinforcing effect, even if the amount added is 25% by weight or less, a molded product with sufficiently high strength can be obtained, and therefore a molded product with excellent nonflammability can be obtained. [Example] Examples 1 to 10 The following compositions were mixed using a mixer. Cement: 47% by weight Silica sand: 30 Perlite: 10 Wood fiber bundle: 10 Aluminum sulfate: 3 The above-mentioned wood fiber bundles are branched and/or curved and/or bent with the following dimensions and bulk specific gravity. Examples Average diameter (mm) Average length (mm) Bulk specific gravity (g/cm ³ ) 1 0.10 20 0.048 2 0.50 20 0.046 3 1.00 20 0.042 4 1.50 20 0.039 5 2.00 20 0.036 6 0.80 10 0.0 45 7 0.80 15 0.043 8 0.80 20 0.042 9 0.80 25 0.040 10 0.80 30 0.038 Water was added to the above mixture to make the moisture content 40% by weight, and then sprinkled on the lower template to form a 55 mm thick mat, and the upper template was placed on the mat. Pressure 10Kg/
cm ² and press hardening at a temperature of 70°C for 25 hours. The obtained molded body is a plate-shaped body with a thickness of 15 mm, and the molded body is then cured in an autoclave at a pressure of 15 kg/cm ² and a temperature of 165° C. for 7 hours. In this way, molded bodies 1 to 10 are obtained. Comparative Examples 1 to 8 Molded articles 11 to 8 were prepared in the same manner as in Examples 1 to 10 using branched and/or curved and/or bent wood fiber bundles having the following dimensions and bulk specific gravity. Get 18. Comparative example Average diameter (mm) Average length (mm) Bulk specific gravity (g/cm ³ ) 1 0.06 20 0.050 2 0.08 20 0.049 3 2.20 20 0.033 4 2.40 20 0.030 5 0.80 6 0.046 6 0.80 8 0.045 7 0.80 32 0.038 8 0.80 34 0.036 The spraying workability, deformability of the pine, and the specific gravity and bending strength of the molded bodies 1 to 18 of the above Examples and Comparative Examples were measured. The results are shown in Tables 1 and 2.
Shown in the table. The shape of the pine is determined by checking whether or not the pine loses its shape when the lower template on which the pine is placed is moved up and down three times with a stroke of 2 cm and a cycle of 1 second. Spraying workability Shapeability Example 1 Good None 2 Good None 3 Good None 4 Good None 5 Good None 6 Good None 7 Good None 8 Good None 9 Good Good No 10 Good No Comparative Example 1 Hard to unravel No 2 Slightly hard to unravel No 3 Good Slightly 4 Good Slight 5 Good Yes 6 Good Slightly 7 Slightly hard to unravel No 8 Hard to unravel None Table 1 Specific gravity (g/cm ³ ) Bending strength (Kgf/cm ² ) Molded object 1 1.00 80 2 0.98 75 3 0.96 70 4 0.93 65 5 0.90 60 6 0.97 65 7 0.97 65 8 0.97 70 9 0.96 75 10 0.96 80 11 1.10 80 12 1.05 80 13 0.85 45 14 0.80 40 15 0.97 50 16 0.97 55 17 0.96 55 18 0.96 50 Table 2 Referring to Table 1 above, average diameter is 0.1 to 2.0 mm, average length is 10 to 3 0mm In Examples 1 to 10, which used wood fiber bundles that were within this range and were branched and/or curved and/or bent, the mixture was easy to loosen, the spraying work was easy, and the formed pine did not lose its shape. It is understood that the wood fiber bundles described above are extremely useful for dry manufacturing methods. On the other hand, in Comparative Examples 1 and 2 using wood fiber bundles with an average diameter of 0.1 mm or less, or Comparative Examples 7 and 8 using wood fiber bundles with an average length of 30 mm or more, the entanglement of the wood fiber bundles became thread-like. This causes problems in spraying workability. In addition, in Comparative Examples 3 and 4 using wood fiber bundles with an average diameter of 2.0 mm or more, or Comparative Examples 5 and 6 using wood fiber bundles with an average length of 10 mm or less, the intertwining of the wood fiber bundles was not sufficient. Poor strength. Therefore, when using the wood fiber bundles of Comparative Examples 1 to 8, it is difficult to apply the dry manufacturing method. Also, referring to Table 2 above, molded products 11 and 12 using wood fiber bundles with an average diameter of 0.1 mm or less have a high specific gravity of 1 or more, and molded product 13 using wood fiber bundles with an average diameter of 2.0 mm or more has a large specific gravity of 1 or more. and 14, or molded body 15 using wood fiber bundles with an average length of 10 mm or less
and 16, the bending strength decreases due to insufficient entanglement of the wood fiber bundles. Furthermore, the average length of the wood fiber bundle is 30 mm.
It can be seen that even with the above conditions, uneven distribution occurs as in the case of molded bodies 17 and 18, so that a molded body with a uniform structure cannot be obtained, and the bending strength is reduced. Example 11 Average diameter 1.0mm, average length 18mm, bulk specific gravity 0.040g/
The following composition is mixed in a mixer using a cm ³ branched and curved wood fiber bundle. Cement 50% by weight Rice ash 20 〃 Diatomaceous earth 10 〃 Wood fiber bundle 15 〃 Calcium chloride 5 〃 Water was added to the above mixture to make the water content 35% by weight, and then sprinkled on the lower template to form a 75mm thick mat. , put the upper mold plate on the mat and apply a pressure of 15 kg/
cm ² and press hardening at a temperature of 75°C for 30 hours. The obtained molded body is a plate-shaped body with a thickness of 20 mm, and the molded body is then cured in an autoclave at a pressure of 17 Kg/cm ² and a temperature of 170° C. for 8 hours. In this way, a molded body 19 is obtained. Example 12 Average diameter 1.5mm, average length 15mm, bulk specific gravity 0.040g/
The following composition is mixed in a mixer using a cm ² curved or bent wood fiber bundle. Cement 45% by weight Silica 30 〃 Fly ash 10 〃 Wood fiber bundle 10 〃 Polystyrene primary foam beads 10 〃 Calcium chloride 2 〃 Water was added to the above mixture to make the moisture content 40% by weight, and then sprinkled on the lower template. A mat with a thickness of 90 mm is used, and the upper mold plate is placed on the mat and a pressure of 20 kg/
cm ² and press hardening at a temperature of 70°C for 25 hours. The obtained molded body is a plate-shaped body with a thickness of 25 mm. The molded body was then cured in an autoclave at a pressure of 15 kg/cm ² and a temperature of 175° C. for 7 hours. Due to the above curing, the polystyrene foam beads undergo secondary foaming to become polystyrene foam spherules, and the polystyrene foam spherules further melt, leaving behind bubbles and the melted polystyrene foam spherules cover the walls of the bubbles. do. In this way, a molded body 20 is obtained. Comparative Example 9 The average diameter of wood fiber bundles in the composition of Example 11
0.08 mm, average length 18 mm, bulk specific gravity 0.059 g/cm ³ pulp fiber 7, thickness 2 denier, length 15 mm polyester fiber was replaced with 3 parts by weight of mixed fibers, and the other conditions were the same to form molded body 21. However, compared to Example 11, it was difficult to uniformly spread the mixture on the lower template because the pulp fibers and polyester fibers were entangled in the mixture. Comparative Example 10 A molded body 22 is produced in the same manner as in Example 11, except that the wood fiber bundle is replaced with a piece of wood that passes through a 10 mm mesh, has a thickness of 0.4 to 1.0 mm, and has a bulk specific gravity of 0.095 g/cm ³ . Since the wood chips were hardly entangled in the mixture, it was easy to mix them uniformly by mechanical stirring, and it was easy to uniformly spread the mixture on the lower template. Test The deformability of the pine of Examples 11 and 12 and Comparative Examples 9 and 10, and the specific gravity and bending strength of molded bodies 19 to 22 were measured. The results are shown in Table 3.

[Table] According to Table 3, in Examples 11 and 12, the mats do not lose their shape, but in Comparative Example 9, even when polyester fibers are mixed, some deformation is observed. In addition, the molded bodies of Examples 11 and 12 are the molded bodies of Comparative Examples 9 and 10.
Compared to 21 and 22, it is clearly lighter and stronger. In addition, the mechanical strength of the molded body 22 is extremely weak, making it almost impossible to put it to practical use. In order to have the same strength as Examples 11 and 12, that is, a bending strength of about 70 kgf/cm ² , it is necessary to add about 30% by weight of wood chips and increase the compaction pressure to about 30 kg/cm ² . be. However, increasing the amount of wood chips added deteriorates the nonflammability of the molded product, and increasing the compacting pressure increases the specific gravity of the molded product to about 1.3, making it heavier, making it impossible to obtain a lightweight and high-strength product. Comparative Example 11 Instead of the wood fiber bundle of Example 1, an average diameter of 0.10
A molded article 23 obtained in the same manner as in Example 1 using unbranched linear wood fiber bundles with an average length of 20 mm and a bulk specific gravity of 0.054 g/cm ³ has a specific gravity of 1.20 g/cm ³ and a bending strength of 60 Kg.
f/cm ² , and the specific gravity is higher than that of molded product 1 listed in Table 1, but the strength is inferior. Comparative Example 12 Instead of the wood fiber bundle of Example 5, an average diameter of 2.3 mm,
A molded article 24 obtained in the same manner as in Example 5 using branched and/or curved and/or bent wood fiber bundles with an average length of 20 mm and a bulk specific gravity of 0.027 g/cm ³ has a specific gravity of 0.86 g/cm 3 . cm ³ and bending strength of 45 Kgf/cm ² , which is inferior to Molded Pair 5 listed in Table 1.

Claims (1)

[Claims] 1. Average diameter is in the range of 0.1 to 2.0 mm, average length is in the range of 10 to 30 mm, and branched and/or curved and/
Alternatively, an inorganic molded article characterized in that a mixture of a wood fiber bundle made bulky by bending and a curable inorganic powder is molded into a predetermined shape and the curable inorganic powder is cured. 2. The inorganic molded article according to claim 1, wherein the bulk specific gravity of the wood fiber bundle is in the range of 0.03 to 0.05 g/cm ³ . An inorganic material characterized by scattering a mixture of a compressed wood fiber bundle and a curable inorganic powder onto a template to form a pine, compressing the pine and curing in the presence of moisture, and then curing in an autoclave. Method for manufacturing a molded object.