JP2001181017A - Calcium silicate plate and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve defective surface smoothness and a problem of fuzzing of calcium silicate plate which has conventionally used a cellulose fiber obtained by beating a wood pulp as a fibrous raw material. SOLUTION: A raw material of calcium silicate molding product is mixed with 2-10 mass % of a cellulose fiber having 70-350 ml freeness and <=40 mass % of residue on sieve having 710 μm sieve opening as a fibrous raw material for the calcium silicate molding product, formed into a fixed shape by a sheet forming method and cured in an autoclave to give a desired calcium silicate plate having excellent surface smoothness, no fuzzing, sufficient flexural strength and interlaminar separation strength as an interior material for building.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a calcium silicate plate widely used as a building interior material.

[0002]

2. Description of the Related Art A calcium silicate plate is prepared by laminating a calcareous raw material, a siliceous raw material, a fiber raw material and an additive (agent) in water by using a round mesh type paper machine, and laminating and shaping the resultant. It is manufactured by curing by performing autoclave curing. Conventionally, asbestos has been frequently used as a fibrous raw material. However, asbestos has been pointed out to be a health problem, and asbestos has been reduced. Therefore, at present, cellulose fibers obtained by beating wood pulp made from softwood or hardwood are widely used as a fibrous raw material in place of asbestos.
No. 44 and JP-A-7-286401 disclose an inorganic cured product or a hydraulic inorganic papermaking product obtained by combining a cellulose fiber having a different fiber length as a reinforcing fiber and an organic synthetic long fiber or an inorganic long fiber.

[0003]

However, cellulose fibers obtained by beating wood pulp have poor dispersibility in water as compared with asbestos fibers, so that the surface smoothness of the product is inferior. Bonding strength is weak, the fibers tend to protrude to the surface of the product, and especially when the polishing treatment is performed to improve the surface smoothness, the protrusion of the fibers becomes remarkable, accompanied by fluffing, and it is difficult to obtain the effect of the polishing treatment. .
Further, when the product is coated, there is a problem that the surface is rough due to the fluff. Further, in JP-A-10-29844 and JP-A-7-286401, although the papermaking property, surface smoothness, or reinforcing property are improved, all use fibers having a relatively long fiber length. However, it is insufficient to prevent fluffing in the calcium silicate plate as in the present invention.

An object of the present invention is to solve the problems of poor surface smoothness and fuzzing which occur on calcium silicate boards using cellulose fibers obtained by beating wood pulp as a fibrous raw material.

[0005]

The invention of claim 1 is a calcium silicate plate comprising a calcareous raw material, a siliceous raw material, a fibrous raw material and an additive (agent). A cellulose fiber having a sieve residue of 70 to 350 ml and an opening of 710 μm and having a sieve residue of 40% by mass or less is divided into 2 parts.
It is a calcium silicate board characterized by containing 10 to 10 mass%.

According to a second aspect of the present invention, the cellulose fiber is waste paper of industrial paper or culture paper, or a mixture of these and unused wood pulp, and the ratio of waste paper of industrial paper or culture paper / unused wood pulp is used. The calcium silicate plate according to claim 1, wherein the ratio is 3/7 or more.

A third aspect of the present invention is a fiber containing cellulose fibers having been subjected to beating treatment in advance, having a freeness of 70 to 350 ml, a sieve residue having a mesh size of 710 μm of 40% by mass or less, and a percentage of 2 to 10% by mass. The calcium silicate according to claim 1 or 2, wherein the raw material, the calcareous material, the siliceous material and the additive (agent) are mixed and dispersed in water, formed into a plate by a papermaking method, and autoclaved. This is a method for manufacturing a plate.

According to a fourth aspect of the present invention, there is provided a fiber containing 70 to 350 ml of freeness and having a sieve residue having an opening of 710 μm having a sieve residue of 40% by mass or less, and 2 to 10% by mass in total. The raw material, the calcareous material, the siliceous material, and the additive (agent) are mixed and dispersed with water, preliminarily formed into a plate by a papermaking method, further press-formed, and then autoclaved. 3. A method for producing a calcium silicate plate according to 1 or 2.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The calcium silicate plate of the present invention contains, as a fibrous raw material, 2 to 10% by mass of cellulose fibers having a freeness of 70 to 350 ml and a sieve having a mesh size of 710 μm and a sieve residue of 40% by mass or less. In the past,
It is characterized in that poor surface smoothness, fluffing due to fiber protrusion, and roughness during coating caused by this are unlikely to occur, which are common in calcium silicate plates using cellulose fibers obtained by beating wood pulp. .

In the present invention, if the freeness of the cellulose fiber used as a fibrous raw material exceeds 350 ml, the raw material slurry is taken out by a paper machine, and the interlayer adhesion when laminating the raw material slurry is deteriorated. Delamination strength decreases. On the other hand, if the freeness is less than 70 ml, the freeness of the raw material slurry is reduced, so that the papermaking property is deteriorated. Furthermore, even if the freeness is in the range of 70 ml to 350 ml, if the sieve residue having an opening of 710 μm exceeds 40% by mass,
It is not preferable because the dispersibility of the fiber is poor, the surface smoothness of the final product is lacking, and fluff is likely to occur. On the other hand, if the addition ratio of the cellulose fiber is less than 2% by mass, the reinforcing property cannot be sufficiently exhibited, and if it exceeds 10% by mass, it is not preferable from the viewpoint of fire resistance and incombustibility. More preferably 3 to
9% by mass.

The term "beating" as used herein refers to mechanical treatment of fibers in water. The fiber assembly is separated and disintegrated into single fibers, and the fibers are cut or longitudinally split as necessary. Means that the fiber is swelled, fluffed, and, if necessary, swells, disintegrates, or slurries the fiber. The freeness represents the degree of drainage of cellulose fibers obtained by beating wood pulp according to the Canadian standard freeness test method specified in JIS P8121, that is, the degree of beating. The smaller the is, the more advanced the beating is. Further, the sieve residue having an opening of 710 μm is a residue of the first tank when the wire mesh of the first tank of the sieving tester is 710 μm in the pulp screening test method specified in JIS P8207. It is represented by the following equation.

[0012]

(Equation 1)

The cellulose fibers are beaten in a conventional manner, for example, by mixing and dispersing waste paper or unused wood pulp with water using a disintegrator such as a pulper to obtain a concentration of 2 to 15% by mass, preferably 3 to 8% by mass. % Of the slurry, it can be beaten to any desired freeness by appropriately adjusting the treatment time or number using a beater beater, rod mill, disc refiner, or the like. In order to obtain a cellulose fiber having a sieve content of 70 to 350 ml and a sieve having a mesh size of 710 μm and a sieve residue of 40% by mass or less, waste paper of industrial paper or culture paper is used alone as a raw material, or these waste paper and unused paper are used. Wood pulp is mass ratio 3
It is preferable to use them together in a ratio of / 7 or more.

When only the unused wood pulp or the waste paper / wood pulp ratio is less than 3/7 by mass, the opening is 710 μm.
Beating until the sieve residue of m is 40% or less is not preferable because the freeness falls below 70 ml. The more preferable waste paper / wood pulp ratio is 4/6 or more, and the upper limit of the waste paper / wood pulp ratio is optimally set to 2/8 in order to minimize the decrease in strength of the molded product.

In the present invention, waste paper used alone or in combination with unused woody pulp is, for example, JIS.
Printing paper specified in P3101, JIS P320
1, writing paper specified in JIS P3202 and JIS P3203, JIS P3401 and JIS P
Kraft paper prescribed in 3412, JIS P330
1. Used industrial paper or culture paper such as drawing paper specified in JIS P3302 and JIS P3303, especially copy paper or form paper used for output from a computer. It is preferable that the material is cut by the above method. Of course, these sheets may be unused at all. As for unused wood pulp, conventionally used softwood or hardwood pulp can be used, and bleached or unbleached wood pulp can be used arbitrarily.

In this manner, 2 to 10% by mass of the cellulose fibers having a freeness of 70% to 350ml and a sieve having a mesh size of 710 μm and a sieve residue of 40% by mass or less are added to all the raw materials of the calcium silicate plate. By doing so, a calcium silicate plate can be manufactured efficiently without lowering the product delamination strength. At the same time, a calcium silicate plate having excellent surface smoothness can be obtained, so that the polishing allowance can be reduced and the nap of the polished product can be eliminated.

The freeness obtained as described above is 350 to 7
As a method for producing a calcium silicate plate using cellulose fibers having a sieve residue of 0 ml and a mesh size of 710 μm and a sieve residue of 40% by mass or less, a calcareous raw material and a silicate Raw materials and additives (agents) are added and mixed, and water is further added to adjust the solid content concentration to about 5 to 15% by mass. It can be cured and manufactured by curing.

The calcareous raw materials include slaked lime, cement,
Alternatively, quicklime is used, and these can be used alone or in combination.Silica powder, fly ash, etc. are used as siliceous raw materials, and diatomaceous earth, silica fume, and white carbon are used as siliceous raw materials for reducing bulk specific gravity. And the like can be used. As for the ratio of the calcareous raw material and the siliceous raw material, the CaO / SiO ₂ molar ratio is preferably in the range of 0.4 to 1.2. More preferably 0.6 to
1.0.

As the reinforcing fibers, glass fibers, carbon fibers, polypropylene fibers, rayon fibers, acrylic fibers, steel fibers and the like can be used in addition to the above-mentioned cellulose fibers.

The shape of the additive (agent) is preferably fibrous, acicular or powdery, and the types thereof are wollastonite, mica, calcium carbonate, talc, perlite, and the like.
Bentonite, sepiolite, gypsum, anhydrous gypsum, concrete waste, calcium silicate plate waste, and the like,
These can also function as fillers or dimensional stabilizers. In addition, the autoclave curing temperature of the calcium silicate board according to the present invention is 120 to 220 ° C, preferably 180 to 200 ° C, and the curing time is 3 to 15 hours. The pre-curing, in which the molded body is left at room temperature, may be performed for 1 to 24 hours before performing the above.

[0021]

The present invention will be described below with reference to examples. First, waste paper and / or cellulose pulp is dispersed with water using a pulper to prepare a cellulose fiber slurry having a concentration of 3% by mass. Then, the slurry is beaten by a beater beater, and the freeness and mesh size are increased. For the combination of 710 μm sieve residue, cellulose fiber slurries having the levels shown in Table 1 were prepared. Here, copy paper was used as waste paper, and bleached softwood pulp was used as unused wood pulp.

Next, slaked lime, silica sand, diatomaceous earth, and additives are added to the slurry containing a predetermined amount of the above-mentioned cellulose fibers so as to have the compounding ratio shown in Table 1, and the mixture is kneaded with water to obtain a slurry having a concentration of about 7% by mass. The product was formed into a molded product having a width of 40 cm, a length of 200 cm, and a thickness of 6 mm by a papermaking method, and then cured at 180 ° C. for 6 hours by an autoclave.

The molded body thus obtained is heated at 105 ° C.
For 24 hours, and the flexural strength was measured according to JIS A1408, with the size of the specimen being No. 4 (30 cm × 25 cm). In addition, the obtained molded body is 5 cm × 5 cm
Then, an iron pulling jig was bonded to both surfaces with an adhesive, and the delamination strength was measured. Table 1 shows the results. Table 1 also shows the results of observation of the conditions during papermaking, the smoothness of the surface of the test specimen, and the fluffing of the surface when the specimen was polished. The calcium silicate molded article obtained in this example had sufficient bending strength and delamination strength as an interior material for building, was free of fluff, and had good surface smoothness.

[0024]

COMPARATIVE EXAMPLE In a combination of freeness and sieve residue having a mesh size of 710 μm, five levels of cellulose fibers which deviate from the scope of the claims as shown in Table 2 were used, and the blending ratios of Examples were as shown in Table 2. A molded body was produced in the same manner, and the same evaluation was performed. Table 2 shows the results. In this case, copy paper was used as waste paper, and bleached softwood pulp was used as unused wood pulp. As shown in Table 2,
If the freeness exceeds the claimed range, the delamination strength is low,
Those having a sieve residue with a mesh size of 710 μm exceeding the claimed range have a lot of fluff and are inferior in surface smoothness. When the freeness was lower than the claimed range, the papermaking property was deteriorated and no test piece could be obtained.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

As described above, calcium silicate plates using cellulose fibers obtained by beating wood pulp as a fibrous raw material have heretofore suffered from poor surface smoothness and fuzziness. Cellulose fibers having a freeness of 70 to 350 ml and a sieve having a mesh size of 710 μm and having a sieve residue of 40% by mass or less as the fibrous raw material are 2 to 10 as in the present invention.
By blending by mass%, it is possible to obtain a calcium silicate plate which is free of fluff, has good surface smoothness, and has sufficient bending strength and delamination strength as an interior material for building.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hikaru Asaga 2-5-5, Tsurumichuo, Tsurumi-ku, Yokohama-shi, Kanagawa F-term in Ask, Inc. 4G012 PA03 PA05 PA22 PA28 PA33 PA33 PB03

Claims (4)

[Claims] 1. A calcium silicate plate comprising a calcareous raw material, a siliceous raw material, a fibrous raw material, and an additive (agent), wherein the fibrous raw material has a freeness of 70 to 350 ml and a sieve residue having an opening of 710 μm. A calcium silicate plate comprising 2 to 10% by mass of cellulose fibers having a content of 40% by mass or less. 2. The cellulose fiber is waste paper of industrial paper or culture paper, or a mixture of the waste paper and unused wood pulp, and the ratio of waste paper of industrial paper or culture paper to unused wood pulp is 3/7. The calcium silicate plate according to claim 1, wherein: 3. A beating process in which the freeness is 70-350.
A fibrous raw material containing 40% by mass or less of a sieve residue having a mesh size of 710 μm and a cellulose fiber content of 2 to 10% by mass, a calcareous raw material, a siliceous raw material, and an additive (agent) are mixed and dispersed with water. The method for producing a calcium silicate plate according to claim 1 or 2, wherein the plate is formed into a plate shape by a papermaking method and autoclaved. 4. A beating process which has a freeness of 70-350.
ml and sieve residue with mesh size of 710 μm is 40 mass%
Hereinafter, a fibrous raw material containing 2 to 10% by mass of cellulose fiber, a calcareous raw material, a siliceous raw material, and an additive (agent)
3. A method for producing a calcium silicate plate according to claim 1 or 2, wherein the mixture is dispersed and mixed with water, and the mixture is temporarily formed into a plate shape by a papermaking method, further subjected to pressure molding, and then subjected to autoclave curing.