JPS62257500A - Moisture absorbable and releasable inorganic fiberboard - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an inorganic fiberboard that has moisture absorption and desorption properties and exhibits excellent humidity control function.

(Prior art and its problems) It has been known that inorganic fiberboards obtained by paper-making inorganic fibers such as rock wool and mineral wool have excellent fire retardant and heat insulating properties. On the other hand, compared to wood fiberboard, its ability to absorb and release moisture is extremely low, so for example,
When used as an interior material for a highly airtight living room structure that emphasizes heating efficiency in winter, the relative humidity will change significantly and frequently due to temperature changes.

For this reason, when heating for a long time, the relative humidity in the room decreases, causing dry skin and the generation of static electricity.
On the other hand, when the heating is turned off, there is a problem in that dew condensation forms on the interior materials.

On the other hand, in order to impart moisture absorption and desorption properties to the non-aluminum fiberboard, it is possible to mix vegetable fibers or add water-absorbing resin, etc., but in the case of the former, fire resistance and heat insulation properties In the latter case, the aluminous fiberboard swells due to moisture absorption, causing strong ignition and dimensional changes.
Therefore, when such an inorganic fiberboard is used for a ceiling material or the like, there is a drawback that sag (sagging) occurs.

In addition, since the water-absorbing resin has a slow rate of moisture release, moisture remains inside the fiberboard, making it easier for the strength to deteriorate.

The present invention was made in view of these problems, and aims to provide an inorganic fiberboard that is not only fire retardant but also has excellent moisture absorption and release properties, and which exhibits little strength loss or dimensional change even when moisture is absorbed. .

(Means for Solving the Problems) The moisture-absorbing and desorbing inorganic fiberboard of the present invention is an inorganic fiberboard obtained by paper-making inorganic fibers such as rock wool and slag wool, and the inorganic fibers are moisture resistant. It is characterized in that it is bonded with a binder and that an alkali metal salt compound having moisture absorbing and desorbing properties is retained inside the fiberboard.

As the moisture-resistant binder that bonds the fibers of inorganic fiberboard together, binders made of moisture-resistant synthetic resins such as phenol resin, melamine resin, or polyvinyl alcohol made water-resistant by increasing the degree of saponification are used. Any inorganic fiberboard may be used as long as it does not reduce the strength of the inorganic fiberboard when it absorbs moisture or water after curing.

The amount of the moisture-resistant binder added is preferably 2 to 10% by weight in order to maintain fireproof properties of the inorganic fiberboard.

In addition, as the alkali metal salt compound, an alkali metal salt such as polyacrylic acid sodium salt, potassium salt, or sodium silicate salt, which has excellent moisture absorption and desorption properties, is used, and the internal amount thereof is determined according to the desired amount. Although it depends on the degree of moisture absorption and desorption ability, it is preferably 3 to 20% by weight.

As methods for internally adding such an alkali metal salt compound to the inorganic fiberboard, there are two methods: adding it together with a fixing agent during wet papermaking, and forcing the mat obtained by papermaking to be impregnated. can.

In the case of the former method, that is, a method in which an alkali metal salt compound is added to the slurry together with a moisture-resistant binder, polyacrylic acid is added to an inorganic fiber such as rock wool together with a water-resistant binder such as melamine, water-resistant polyvinyl alcohol, or phenol. Paper is made by adding an alkali metal salt such as sodium and an anionic fixing agent, and then dried. According to this method, moisture absorption and desorption properties are uniformly imparted throughout the interior of the inorganic fiberboard. be able to.

In the above method, especially sodium polyacrylate,
Because it gels in water through intermolecular cross-linking, it can be added to slurry and fixed on the intersecting parts of inorganic fibers, and compared to water-soluble alkali metal salts such as sodium silicate, it is less likely to leak into white water. No migration occurs during drying (a phenomenon in which a large amount of alkali metal salt migrates to the surface layer due to the movement of moisture), and it can be uniformly dispersed and added internally.

In addition, when using a water-soluble alkali metal salt such as sodium silicate in the method of papermaking by mixing an alkali metal salt compound in an aqueous slurry, it is necessary to neutralize it with an acid in advance to form a water-insoluble gel-like salt. Either make it into a substance and then add it, or
Alternatively, if it is added after reacting with a curing agent such as glyoxal or maleidialdehyde to form a gel, the metal salt compound will not flow out into white water during papermaking and will be retained sufficiently inside the fiberboard. can.

In this way, when sodium silicate is reacted with an acid or a hardening agent in advance to form a gel, the gel-like material will form a large lump, so it is preferable to thoroughly crush it before mixing. It is best to cool the slurry with water or the like so that it cools down to a certain temperature, and then add it without raising the water temperature of the slurry too much.

Note that a water-soluble alkali metal salt and an acid or a hardening agent may be added to the slurry at the same time to form a gel in the slurry, but at this time, the slurry must be sufficiently stirred to prevent the gel-like substance from forming large lumps. It is made into paper.

On the other hand, in the case of the latter impregnation method, a wet mat is formed by paper-making inorganic fibers such as rock wool together with a moisture-resistant binder, and then an aqueous solution of sodium silicate is applied to the surface of the wet mat, and the back side of the mat is The fiberboard is formed by applying vacuum suction to forcibly impregnate the fiberboard from the surface layer to the inside with the sodium silicate aqueous solution, and then drying the fiberboard. A particularly large amount of an alkali metal salt compound can be added internally to the surface layer of the material. Therefore, when used as an interior material, for example, the surface layer with a large amount of alkali metal salt compound added internally facing the indoor side. By installing it, it is possible to increase the moisture absorption and release properties of the room.

(Function) Since the inorganic fiberboard is bonded with a moisture-resistant binder, the strength does not decrease when moisture is absorbed, and the moisture-absorbing and desorbing alkali metal salt compound added inside the fiberboard allows the inorganic The fiberboard not only has hygroscopic properties, but also has good moisture release properties, allowing it to absorb and release moisture in a short period of time while responding to changes in environmental humidity.Moreover, by adding a large amount of this alkali metal salt compound to the inorganic fiberboard. However, the fire resistance of the inorganic fiberboard is not impaired.

(Example) Next, examples of the present invention will be shown.

Example 1 0 inch wool 92 weight water resistant polyvinyl alcohol 5 Sodium polyacrylate 3 Fixative (acrylamide type, anionic) 0.01 The above blended composition was poured into water and stirred to form a slurry, This slurry was formed into a wet mat of inorganic fibers using a circular paper machine, and the wet mat was dried at high temperature using a dryer to obtain an inorganic fiberboard having a specific gravity of 0.38.

Example 2 After adding sulfuric acid to an aqueous sodium silicate solution and causing a neutralization reaction between the two to precipitate a gelled sodium silicate sulfate, a large amount of water was added to this gelled sodium silicate salt. The mixture was further finely ground using a beater, and unreacted sodium silicate and sulfuric acid bones were diluted to lower the temperature of the reaction solution to room temperature.

Next, the above-mentioned dispersion of gel-like sodium silicate salt is mixed into a rock wool slurry with a solid content of 90% rock wool, 5 parts water-resistant starch, 5 parts gel-like sodium silicate salt, 5 parts fixing agent, and 0.01 parts solid content. A wet mat of inorganic fibers was formed by pouring and stirring the mixture into a paper-making machine using a circular mesh paper-making machine, and the wet mat was dried with a dryer to obtain an aluminous fiberboard having a specific gravity of 0.38.

Example 3 0Tsuku wool 85% by weight Hydrated polyvinyl alcohol 5 Lightweight inorganic aggregate
10. Pour the above blended composition into water and stir to make a slurry,
A 10% sodium silicate aqueous solution was applied to the surface of the wet mat obtained by making paper from this slurry using a round net paper making machine.
A sodium silicate aqueous solution is sprayed and applied to the inside of the mat, and then the inside of the mat is forcibly impregnated with an aqueous sodium silicate solution that is dehydrated and applied to the front side by suction from the back side of the mat using a vacuum suction device. After drying, an inorganic fiber board was obtained in which a large amount of sodium silicate crystals were deposited on the surface layer.

The inorganic fiberboards obtained by the methods of Examples 1 to 3 above are designated as A, B, and C, respectively, and the inorganic fiberboard obtained by the conventional method without impregnating with sodium silicate in Example 2 is designated as D. A comparison table of moisture absorption and release properties is shown below.

In addition, the moisture absorption and release experiment was conducted to determine the daily moisture absorption amount of the non-aluminum fiberboard when changing the environmental condition from a temperature of 25°C and a relative humidity of 50% to a humid environment of a temperature of 25°C and a relative humidity of 80%. Conversely, this was done by detecting the amount of moisture released in one day when the environmental conditions were changed from a temperature of 25° C. and a relative humidity of 80% to a temperature of 25° C. and a relative humidity of 50%.

As is clear from the table above, the inorganic fiberboards obtained in Examples 1 to 3 of the present invention exhibit superior moisture absorption and desorption properties compared to conventional inorganic fiberboards, and therefore can be used as interior materials. In this case, it exhibits an effective humidity control function in response to the relative humidity in the room, and can prevent dew condensation from forming on walls and the like.

(Effects of the Invention) As described above, the inorganic fiberboard of the present invention is an inorganic fiberboard obtained by wet forming inorganic fibers such as rock wool or slag wool, and the inorganic fibers have moisture resistance. Since the inorganic fiberboard is porous and easily permeable to air and moisture, the fiberboard is bonded with a binder and contains an alkali metal salt compound with moisture absorbing and desorbing properties inside the fiberboard. The alkali metal salt compound held inside the board exhibits sufficient moisture absorption and desorption properties, and even if the compound swells and contracts due to moisture absorption and desorption, even if the compound swells and contracts within the voids of the fiberboard, The compound simply swells and contracts repeatedly within the voids of the fiberboard, and the entire fiberboard does not expand or contract, resulting in excellent dimensional stability.Also, even when the alkali metal salt compound absorbs moisture, the inorganic fiber itself does not absorb moisture. There is no dimensional change, and since the inorganic fibers are bonded together by a moisture-resistant binder, the bonds between the fibers will not loosen, and the fiberboard will not swell, lose strength, or deform when it absorbs moisture. As a result, there is no sag (sagging) when used for ceiling materials, etc.

Furthermore, by uniformly containing an alkali metal salt compound throughout the inside of the inorganic fiberboard, when used as an interior material, if the inside of the wall becomes humid due to wall materials, etc., it will absorb moisture and move away from the indoor surface. It is possible to control the humidity in a space that is in contact with both sides by releasing moisture, and if the alkali metal salt compound is densely distributed and contained only on one side of the inorganic fiberboard, it is possible to control the humidity in a space that is in contact with both sides. When used as ceiling material,
The absorbed moisture is retained in the ceiling material and can be absorbed only inside the room, regardless of the humidity condition in the attic.

Patent applicant: Daiken Kogyo Co., Ltd.-7 Agent: Patent attorney Nakao Fusatabe.

: Procedural city’ UK writing initiative) May 22, 1986

Claims (3)

[Claims] (1) An inorganic fiberboard obtained by paper-making inorganic fibers, in which the inorganic fibers are bonded together by a moisture-resistant binder, and an alkali metal salt compound having moisture absorption and desorption properties is internally added to the inside of the fiberboard. A moisture-absorbing and desorbing inorganic fiberboard characterized by the ability to retain moisture. (2) Claim 1 characterized in that the alkali metal salt compound is internally retained densely in the surface layer on one side of the inorganic fiberboard and sparsely on the surface layer on the other side.
Moisture-absorbing and desorbing inorganic fiberboard as described in . (3) The moisture-absorbing and desorbing inorganic fiberboard according to claim 1, wherein an alkali metal salt compound is uniformly added and retained inside the inorganic fiberboard.