JPS6012480B2 - Manufacturing method of inorganic fiberboard - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an inorganic fiberboard with excellent moisture resistance.

More specifically, when using polypynyl alcohol (hereinafter abbreviated as PVA) as a binder in a method for wet papermaking and board manufacturing of inorganic fibers such as asbestos, Kimishin, Hachiminato fiber, asbestos, glass fiber, and gypsum fiber, , by coexisting shelf acid or its salt and either sodium aluminate or sodium stannate, the migration of the binder to the surface layer of the fiberboard is suppressed and the yield of the binder inside the fiberboard is increased, The present invention relates to a method for producing an inorganic fiberboard that has excellent adhesive properties and moisture resistance.

Traditionally, inorganic fiberboards have been manufactured by dispersing rock wool together with a binder in a large amount of water to form a paper, then removing the liquid and adjusting the thickness by applying pressure or suction, and then removing the binder by heating and drying. This was done by gelatinization and hardening.

As the binder used at this time, various starches such as wheat flour starch, tapioca starch, and cornstarch have been used. However, when these starches are used as a binder, the resulting inorganic fiberboard has poor water resistance, particularly moisture resistance, and has the disadvantage of swelling upon absorption of moisture, resulting in a significant decrease in mechanical performance.

Furthermore, when PVA is used instead of starch, PVA migrates to the surface layer of the fiberboard during heat drying, and the resulting fiberboard has the disadvantage of poor uniformity in mechanical performance.
cannot take advantage of its excellent adhesive performance. Therefore, the present inventors first added shelf acids or their salts to PVA to improve the yield rate of the binder and to suppress the migration of PVA to the surface layer during heat drying, thereby improving bush setting. Method for manufacturing inorganic fiberboard (Tokukoshi 49-924)
79), but even with this method, Experiment No. 79, which will be described later.
As is clear from No. 1, it is difficult to obtain an inorganic fiberboard with sufficiently excellent moisture resistance. As a result of further research based on such technology, the present inventors found that for the papermaking and board production of inorganic fibers, a method consisting of PVA, shelf acid or its salt, and either one of sodium aluminate or sodium stannate was used. It has been found that the use of a binder is more effective in improving the green resistance of inorganic fiberboards.

In other words, when making inorganic fibers scaled with a large amount of water, a shelf acid or its salt and either sodium aluminate or sodium stannate are added to PVA, and the paper is made by a conventional method, and then heated and dried. We have discovered that it is possible to produce an inorganic fiberboard that satisfies the various points of high adhesion effect and has excellent moisture resistance.In the present invention, these PVA and shelf acid or a salt thereof and any one of sodium aluminate or sodium stannate, such as asbestos, mineral wool, asbestos, glass fiber, gypsum fiber, etc., with a fiber length of 1 to 15 mm, preferably 10 to 30 mm, and a diameter of 1 mm. ~50 Buddhas, preferably 5
The desired inorganic fiberboard can be obtained by blending the inorganic fibers with ~10 ml of inorganic fibers in a large amount of water, dispersing the slurry in a slurry form, and then forming the slurry into paper and making a board.

The blending ratio of each component in the slurry is 10 to 20 parts by weight, preferably 20 parts by weight of inorganic fiber to 100 parts by weight of water.
~100 parts by weight, PVAO. 2 to 4 parts by weight, preferably 0.3 to 30 parts by weight, 0.2 to 4 parts by weight, preferably 0.3 to 30 parts by weight, of a shelf acid or a salt thereof, either sodium aluminate or sodium stannate. or 1 type 0.5
~40 parts by weight. If the blending ratio of PVA, shelf acid or its salt, and either sodium aluminate or sodium stannate to the inorganic fiber exceeds the above range, a satisfactory adhesive effect may not be obtained.
Otherwise, it is undesirable because it only unnecessarily increases the amount of flammable substances in the fiberboard.

The above-mentioned three-component composition is effective as a binder for inorganic fiberboards, unlike when shelf acid or its salt and either sodium aluminate or sodium stannate act independently. Due to the synergistic effect of the combined use, PVA rapidly gels or becomes immovable at a certain temperature during heat drying, and therefore, after sufficiently permeating between the inorganic fibers, PVA The gelation or water-insolubilizing action of the salt and either sodium aluminate or sodium stannate suppresses migration to the surface layer of the fiberboard, forming a water-insolubilizing film that firmly fixes inorganic fibers. It is thought that this is because of this.

As the PVA used in the present invention, any water-soluble PVA can be used, but from the viewpoint of mechanical properties, a degree of saponification of 95 mol % or more and a degree of polymerization of 1000 or more are desirable.

PVA is conveniently added in the form of powder, but in this case, the particle size is preferably relatively fine, with a 50-mesh pass. Tase sand ~ Sodium metatrate, Potassium shelate,
Examples include water-soluble shelf salts such as ammonium shelf acid.

In the present invention, it is effective to use either sodium aluminate or sodium stannate, and other metal salts such as aluminum sulfate, calcium chloride, magnesium chloride, aluminum chloride, ammonium acetate, etc. So, experiment No. 9 to be described later.
As is clear from No. 13, sufficient green resistance cannot be expected.
In the present invention, water-soluble polymers such as starch, polyacrylamide, and carboxymethylcellulose, cationic and anionic latexes, and emulsions may be used in combination.

Furthermore, various fillers, preservatives, waxes, etc. may be mixed in depending on various purposes. Next, the present invention will be explained with reference to Examples. Example 1 Using rock wool as the rock fiber, a fiberboard was made with the composition shown in Table 1, and then dried in a hot air dryer at 160°C for 3 hours to produce a rock wire fiberboard with a thickness of 12 ribs. I got it.

Samples were taken from this fiberboard to a size of 1 inch thick, 2 mm thick, and 8 hills long, and these were measured under normal conditions (2000℃, relative humidity 65%) and moisture absorption (30℃, relative humidity 90%). After drying under the following conditions, the surface hardness was measured.

For comparison, shelf sand and sodium stannate were each used individually.
Experiments using VA were conducted and are shown in Table 1. Table -
1 Note *IPV A: ■Vorivinyl alcohol manufactured by Kuraray Polymerization degree 1700, saponification degree 99.5% mole *2 Surface hardness: ■Value measured with a thread-wound hardness meter manufactured by Shimadzu.

The hardness values in the table indicate the numbers on the indicating scale of the hardness meter. Table -
1 to Experiment No. 1 of the present invention. It can be seen that by adding shelf sand and sodium stannate to PVA as shown in 3 and 4, the surface hardness, especially when moisture is absorbed, is high, and the moisture resistance is excellent.

Example 2 Experiment No. of Example 1. In 3-4, sodium aluminate was used instead of sodium stannate, and a fiberboard sample was obtained in the same manner as in Example 1, and its surface hardness was measured.

The results are shown in Table-2. Also, experiment no. In 3 and 4, 0.0% of sodium aluminate was used instead of sodium stannate.
A fiberboard sample was obtained in the same manner as in Example 1 using a 600 ml sample, and its surface hardness was measured.

The results are also listed in Table-2. For comparison, Experiment No. 2
and no. In Example 4, aluminum sulfate, calcium chloride, magnesium chloride, aluminum chloride, and aluminum acetate were used instead of sodium stannate, and the surface hardness of the fiberboard sample obtained was measured in the same manner as in Example 1.

The results are also listed in Table-2. -2 From Table-2, experiment No. of the present invention. PVA like 6 and 7
It can be seen that by adding shelf sand and sodium aluminate to the surface, the surface hardness, especially when moisture is absorbed, is high, and the moisture resistance is excellent.

Example 3 Experiment No. 4 and 7, using shelf acid instead of shelf sand,
Thereafter, a fiberboard sample was obtained in the same manner as in Example 1, and its surface hardness was measured.

The results are shown in Table-3. Table-3 From Table-3, experiment No. of the present invention. As in 15-16,
It can be seen that by adding shelf acid and sodium stannate or sodium aluminate to PVA, the surface hardness, especially when moisture is absorbed, is high and the moisture resistance is excellent.

Claims (1)

[Claims] 1 10 to 200 parts by weight of inorganic fiber, 0.2 to 40 parts by weight of polyvinyl alcohol, 0.2 to 40 parts by weight of boric acid or its salt, and one of sodium aluminate or sodium stannate per 1000 parts by weight of water. .5～
40 parts by weight were blended to form a slurry, which was then made into a paper.
A method for manufacturing an inorganic fiberboard with excellent moisture resistance, which comprises board manufacturing.