JPH0422869B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a gypsum board with excellent nonflammability. Gypsum board has been widely used as an interior material because of its various features such as flame retardancy, easy workability, and low price. In particular, flame retardancy is the most outstanding feature of gypsum board, but in recent years, due to fire prevention requirements, noncombustible gypsum board with even higher flame retardance has been required. A gypsum board can be roughly divided into a gypsum core and a board base paper that covers the gypsum core. Since the gypsum core material part is mainly composed of gypsum, which is inherently nonflammable, the nonflammability of the gypsum board depends solely on the base paper for the board. Conventional base paper for gypsum board is made from combustible waste newspapers and cardboard, so conventionally, when manufacturing non-combustible gypsum board,
Glass cloth, asbestos paper, etc. have been used instead of the above-mentioned general board paper. However, these are not only expensive, but also have fatal flaws such as insufficient adhesion to the gypsum core material and low strength of the gypsum board itself, so they are not completely satisfactory. Ta. For this reason, a noncombustible gypsum board using a board base paper in which the surface layer of a general board base paper is composed of an asbestos layer has also been proposed. However, asbestos is a substance that is harmful to the human body, and due to its nature, asbestos is a substance that is hazardous to the human body, and manufacturing processes that handle such substances require extreme care and must be extremely complicated. As a result of intensive studies to solve these problems, the present inventors found that gypsum board using board base paper containing boric acid has excellent nonflammability. By containing boric acid and/or borate,
They discovered that it has excellent nonflammability and completed the present invention. That is, the present invention is a non-combustible gypsum board in which a gypsum core is covered with a base paper for board containing boric acid and/or a borate, and further includes hemihydrate gypsum powder, an extender, a curing time regulator, and a strength agent. Non-combustible gypsum obtained by adding various additives such as reinforcing agents, adhesive reinforcing agents, waterproofing agents, dispersants, etc. and water, kneading the resulting gypsum slurry, and adding boric acid and/or borates to the gypsum slurry. The present invention provides a noncombustible gypsum board made by coating or spraying or impregnating a gypsum board with an aqueous solution of boric acid and/or a borate. The present invention will be explained in detail below. The gypsum board of the present invention is used as the board base paper,
There is no difference from ordinary gypsum board except that it contains boric acid and/or borate (hereinafter referred to as boric acid). The boric acid used in the present invention includes orthoboric acid,
It may be in any form such as metaboric acid, tetraboric acid, pentaboric acid, or haboric acid. Further, as the borate, the various salts of boric acid mentioned above can be used. That is, such salts include salts of alkali metals such as lithium salts, sodium salts, potassium salts, rubidium salts, and cesium salts; salts of alkaline earth metals such as beryllium salts, magnesium salts, calcium salts, strontium salts, and barium salts; and titanium salts. salt, vanadium salt, chromium salt, molybdenum salt, manganese salt,
iron salt, cobalt salt, nickel salt, palladium salt,
Salts of transition metals such as copper salts, zinc salts, cadmium salts;
and ammonium salts. The board base paper containing boric acid, etc. used in the present invention can be produced by any method. For example, one method is to sand the base paper using an aqueous solution such as boric acid during the production of the base paper. In other words, waste paper is used as the main raw material, and a small amount of pulp, etc. is added to it, which is disintegrated with a pulper, and then beaten with a refiner, etc., and then an appropriate amount of the above-mentioned boric acid, etc. is added along with additives such as sizing agents and pigments, and then the paper is made into yen. It can be sanded and dried using a sandpaper machine such as a paper machine. In addition, as another method, it is of course possible to manufacture this by coating or spraying an aqueous solution such as boric acid on the surface of a general base paper for board, impregnating it, and drying it. As another method, the boric acid impregnation operation can be carried out simultaneously during the production of gypsum board without preparing the boric acid-containing base paper in advance as described above. In other words, gypsum board is usually made by adding various additives such as fillers, curing time regulators, strength reinforcing agents, adhesive reinforcing agents, waterproofing agents, dispersants, etc. to hemihydrate gypsum powder, which is the main raw material, and water, and then thoroughly kneading the mixture. The resulting gypsum slurry is poured out between the top and bottom sheets of gypsum board base paper, which are continuously fed out, and is pressed with rolls to form a board. Therefore, in order to manufacture the gypsum board of the present invention, when preparing the above-mentioned gypsum slurry, it is sufficient to add boric acid or the like to the slurry together with the above-mentioned additives and knead well. Boric acid, etc. in the slurry (which is naturally considered to be in the form of an aqueous solution) is poured out between the gypsum board base papers as described above and comes into contact with the board base paper, and It quickly penetrates into the base paper for board, and as a result, a noncombustible gypsum board equivalent to that obtained using base paper for gypsum board that has been pre-contained with boric acid or the like can be obtained. In addition, as yet another method, the noncombustible gypsum board of the present invention can be obtained by applying, spraying, and impregnating the surface of an ordinary gypsum board manufactured using ordinary base paper for gypsum board with an aqueous solution such as boric acid, and then drying it. Of course you can get it. In the present invention, the amount of boric acid etc. to be contained in the base paper for board is 1 part or more, preferably 2 to 5 parts, based on 100 parts by weight (hereinafter simply referred to as parts) of the base paper. In addition, when adding to gypsum slurry, for 100 parts of gypsum hemihydrate, which is the main raw material,
The amount is 0.1 part or more, preferably 0.3 to 4.0 parts. If the amount added is less than 0.1 part, it is not preferable because the effect of the present invention of imparting nonflammability cannot be achieved. Furthermore, even if more than 4.0 parts are added, not only can no further effect be expected, but
In fact, it is not preferable because it may worsen the adhesion between the gypsum board and the base paper for board. As shown in the examples below, the gypsum board coated with the base paper for gypsum board containing boric acid, etc. of the present invention not only has extremely excellent nonflammability, but also has excellent non-flammability when conventional glass cloth etc. are used. There are no unavoidable disadvantages such as insufficient adhesion to the gypsum core or a decrease in the strength of the gypsum board itself. Moreover, it goes without saying that the manufacturing process is no different from the case where ordinary base paper for gypsum board is used and can be easily manufactured. Hereinafter, the present invention will be explained in more detail with reference to Examples. Comparative Example 1 100 parts of hemihydrate gypsum powder, 80 parts of water, 0.5 part of starch, and 0.1 part of potassium sulfate were quickly and thoroughly mixed to form a slurry. The slurry was poured between two sheets of base paper for board weighing 250 g/m ² and pressed with a roll to solidify. After solidification, it was dried at 60°C for 24 hours to obtain a gypsum board. Comparative Example 2 A gypsum board was obtained in the same manner as in Comparative Example 1, except that one of the two board base papers was replaced with a commercially available asbestos laminated boat base paper with a basis weight of 350 g/m ² . Comparative Example 2 is commercially available as a noncombustible gypsum laminate (general certification noncombustible No. 1004) specified by the Ministry of Construction. Example 1 In Comparative Example 1, the base paper for boats was preliminarily soaked in a 2% orthoboric acid (hereinafter simply referred to as boric acid) aqueous solution for about 1 hour.
A gypsum board was obtained in the same manner as in Comparative Example 1, except that the board was soaked for an hour, impregnated with boric acid, and dried at 60°C for 24 hours. The amount of boric acid contained in the base paper was calculated from the amount of water pumped into the base paper, and was approximately 2 parts per 100 parts of the base paper. Example 2 A gypsum board was obtained in the same manner as in Example 1 except that a 5% boric acid aqueous solution was used. The amount of boric acid contained in the base paper was calculated from the amount of water pumped into the base paper, and was approximately 4 parts per 100 parts of the base paper. Example 3 A gypsum board was obtained in the same manner as in Comparative Example 1, except that 0.3 parts of powdered boric acid was added to 100 parts of gypsum hemihydrate to form a slurry. In addition, it was found that the boric acid added to the slurry was transferred to the base paper used, and it contained about 2 parts of boric acid per 100 parts of the base paper. Example 4 A gypsum board was obtained in the same manner as in Example 3 except that 4 parts of powdered boric acid was added. It was found that the boric acid added to the slurry material migrated to the board base paper used, and that it contained about 3 parts of boric acid per 100 parts of the base paper. Comparative Example 3 A gypsum board was obtained in the same manner as in Example 3 except that 5 parts of boric acid (powder) was added. After drying, this gypsum board was easily peeled off due to poor adhesion between the base paper and the gypsum core material. Comparative Example 4 A moth-eaten pattern was pressed on the surface of the base paper for asbestos laminated gypsum board obtained in Comparative Example 2, and then a white paint containing vinyl acetate emulsion, calcium carbonate, and titanium oxide as main components was applied on top of it. It was dried at 60°C for 24 hours to obtain a decorative gypsum board.
In addition, Comparative Example 3 is commercially available as a noncombustible gypsum laminate (general rule certification noncombustible No. 1004) specified by the Ministry of Construction. Example 5 The gypsum board obtained in Comparative Example 1 was treated in the same manner as in Comparative Example 4 to obtain a decorative gypsum board. Example 6 A 5% boric acid aqueous solution was applied and penetrated onto the surface of the base paper for gypsum board obtained in Example 1 until the amount of boric acid contained in the base paper exceeded 2 parts per 100 parts of the base paper. A gypsum board was obtained by repeated processing and drying at 60°C for 24 hours. Example 7 A gypsum board obtained by soaking the gypsum board obtained in Comparative Example 1 in a 5% boric acid aqueous solution for about 10 minutes to impregnate it with boric acid and drying it at 60°C for 24 hours was obtained. It was found that about 2 parts of boric acid was contained. Regarding the gypsum boards and decorative gypsum boards obtained in Comparative Examples 1 to 4 and Examples 1 to 7 above,
Table 1 shows the results of base material tests and surface tests conducted in accordance with the flame retardancy test method specified in JIS A 1321.

【table】

[Table] The present invention manufactures non-combustible gypsum board by coating or spraying an aqueous solution of boric acid and/or borate on base paper for gypsum board, and by spraying impregnation and drying. Boric acid and/or borate added to the gypsum slurry is transferred to the base paper to produce non-combustible gypsum board, which can be manufactured without major changes to the conventional manufacturing method. , is a simple method. As is clear from Table 1, the gypsum board of the present invention and the crystalline gypsum board derived therefrom are made using asbestos laminated board base paper, which is a typical conventional noncombustible gypsum board. It can be seen that the material has excellent flame retardant properties, equivalent to that of gypsum board.

Claims (1)

[Scope of Claims] 1. A gypsum board comprising a gypsum core covered with board base paper, characterized in that the board base paper and/or the gypsum core contain boric acid and/or borate. Non-combustible plasterboard. 2. The noncombustible gypsum board according to claim 1, wherein the base paper for board contains boric acid and/or borate. 3. The noncombustible gypsum board according to claim 1, wherein the gypsum core contains boric acid and/or borate. 4. The noncombustible gypsum board according to claim 1, wherein the surface of the gypsum board is coated, sprayed, or impregnated with an aqueous solution containing boric acid and/or a borate, and then the gypsum board is dried.