JPH0248505B2 - MUKISHITSUZAIRYONOSEIZOHOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for obtaining a water-resistant inorganic material by adding a coagulant to water glass and solidifying the water glass.

Usually, water glass is a concentrated aqueous solution of an alkali silicate salt obtained by melting silicon dioxide and an alkali, and is a colorless and highly viscous liquid. Also, when the water glass is left in the air, the water evaporates,
It has the property of solidifying.

Therefore, water glass having the above-mentioned properties is widely used as a bonding agent, a paint, a soil hardening agent, and the like.

However, this water glass has the drawback of poor water resistance. That is, even if the water glass is allowed to solidify by leaving it at room temperature or by heating, the resulting solidified product becomes a viscous liquid again when it comes into contact with moisture.

Therefore, it is difficult to use the water glass for articles installed in humid places, as well as in places where water is directly exposed, such as outdoors.

Furthermore, when the water glass is heated to 150° C. or higher after solidification, its strength decreases significantly and it loses its function as a molded body, adhesive, or paint.

On the other hand, it is known to add multivalent ions such as magnesium and calcium to water glass in order to impart water resistance and heat resistance to the water glass.

However, when the above-mentioned ions are simply added in the form of an aqueous solution as in the past, the water glass rapidly solidifies into a gel-like state, resulting in poor workability when molding the water glass into a certain shape or coating it. , impractical.

The present inventor has conducted intensive research aimed at overcoming the above-mentioned disadvantages of water glass, such as rapid solidification, and has finally achieved the present invention.

The first invention according to the present application is a method for producing an inorganic material obtained by adding multivalent ions to water glass, molding and solidifying the water glass, and in which an adsorption step in which a porous powder made of one or both of sepiolite and attapulgite is impregnated with or adsorbed with valence ions to produce a coagulant; a mixing step in which the coagulant is mixed with water glass to form a mixture; A method for producing an inorganic material (hereinafter referred to as the first invention) comprising a molding step of molding a mixture into a desired shape and solidifying it.

According to the first invention, the coagulant impregnated with or adsorbed with multivalent ions has sustained release properties, that is, the property of gradually releasing the multivalent ions into the water glass. Does not solidify rapidly. The process of the invention therefore has a fairly long and adjustable pot life and is easy to work with. Moreover, the inorganic material obtained by the present invention is
Since it has excellent water resistance and heat resistance, it can be widely used as a material for construction and civil engineering.

The present invention will be explained in more detail below.

As the ion supply substance used in the present invention,
It is a salt containing multivalent ions such as Mg, Ca, Ba, Al, etc., and in the present invention, one type or a mixture of two or more of these is used. As a specific salt,
Water-soluble materials such as CaCl ₂ , Mg(NO ₃ ) ₂ , Ba(OH) ₂ , and AlCl ₃ are preferable.

On the other hand, for the porous powder that impregnates or adsorbs the multivalent ions, one or both of sepiolite and attapulgite is used.

The above-mentioned sepiolite and attapulgite are minerals whose main components are hydrated magnesium silicate, hydrated magnesium, and aluminum silicate, respectively, and their structure is an aggregate of long fibers with a quadrilateral cross section of about 0.1 μm on a side, and inside the aggregate has a large number of holes in the length direction of the fiber.

The porous powder in the present invention is obtained by pulverizing the above-mentioned sepiolite or attapulgite using a mill or the like, and the particle size thereof is preferably in the range of 20 to 500 μm.

In the adsorption step according to the first invention, the multivalent ions are adsorbed onto the porous powder. In the adsorption step, first, the salt containing the multivalent ions is liquefied, and then the ions are brought into contact with the porous powder by, for example, immersing the porous powder in this liquid. The solvent for making the above salt into a liquid state is preferably water, alcohol, or other volatile organic solvents. The concentration of the liquefied salt is preferably close to the solid solubility limit determined by the salt and the solvent. However, there is no problem even if the concentration is lower than this.

Another method for carrying out this adsorption step is to bring the salt into a molten state or a gaseous state, and then bring the porous powder into contact with the salt.

As described above, multivalent ions are adsorbed to the porous powder by ion exchange adsorption or physical adsorption,
Alternatively, as a result of penetrating into pores opened on the surface of the porous powder, the porous powder and multivalent ions are strongly combined.

Thereafter, excess solution merely adhering to the surface of the porous powder is removed by washing with water or the like to obtain a porous powder impregnated with or adsorbed with polyvalent ions as a coagulant according to the present invention.

Next, in the mixing step according to the first invention,
Water glass and the above-mentioned coagulant are mixed and kneaded.

The water glass in the present invention is a substance represented by the general formula M ₂ O・nSiO ₂ (M is an alkali metal such as K, Na, Li, etc. or a group such as NH ₄ , and n is 1
The number is ~4. ) (hereinafter this substance is referred to as water glass solid content) is a 10 to 70% by weight (ωt%) aqueous solution.

In this case, the mixing ratio of the water glass solid content and the porous powder should be such that the amount of multivalent ions impregnated or adsorbed in the porous powder is equivalent to the alkali metal ions in the water glass. good.

Note that an appropriate amount of water may be added to facilitate the mixing and kneading operations described above. The kneading work in this mixing step may be done manually or by using a steel kneader.

In this manner, a mixture having a relatively long pot life can be obtained. Note that the pot life can be adjusted by the type and amount of the multivalent ions and porous powder.

Finally, the mixture obtained in the above mixing step is molded into a desired shape in a molding step and solidified. The method of molding the mixture includes a method of injecting the mixture into a mold, a method of molding the mixture without using a mold,
There are methods of applying it to the substrate with a brush, spatula, etc. When molding by pouring into a mold, the viscosity of the mixture may be relatively low; however, when a mold is not used, it is desirable to keep the viscosity high enough to prevent deformation due to its own weight. On the other hand, when applying with a brush or spatula, it is desirable to use a relatively low viscosity.

The above-mentioned solidification may be carried out by natural drying at around room temperature, or by drying or baking at an elevated temperature if necessary. When increasing the temperature, increase the temperature to 110-250
When the temperature is selected within the range of 0.degree. C., the mixture according to the present invention exhibits even better water resistance and heat resistance after solidification.

By carrying out each of the above steps, an inorganic material containing water glass as a main component can be obtained.

According to the present invention, the polyvalent ions that solidify the water glass are released little by little from the porous powder, thereby increasing the pot life of the mixture according to the present invention. Therefore, workability in the molding process is improved.

Further, since the mixture has appropriate viscosity, the initial adhesive strength is high.

The inorganic material obtained by the present invention has water resistance and heat resistance due to the reaction between the coagulant and water glass. Even when the surface of the inorganic material is sprinkled with water and rubbed, the inorganic material not only does not dissolve, but even when left in hot water at 60° C. for a long time, it does not dissolve or even swell.

Further, the inorganic material does not foam even when heated to 600°C.

In addition, in this mixing step, in addition to the porous powder and water glass, for example, silica sand, glass powder,
Inorganic substances such as glass fiber, mica, bentonite, talc, and asbestos, and organic substances such as rubber latex and cellulose fibers, which do not adversely affect the properties of water glass, may be added as fillers as appropriate. . Addition of these substances has the advantage of reducing the shrinkage rate of the water glass during solidification in the molding process.

As described above, the inorganic material obtained according to the first invention has excellent features. Therefore, it can be applied with a brush and used as an adhesive for cardboard, foam glass moldings, etc., or as a surface coating material for foam glass moldings.

The second invention according to the present application is a method for manufacturing an inorganic material having the same properties as the first invention, in which Mg, Ca, Ba,
An adsorption step in which a coagulant is produced by impregnating or adsorbing polyvalent ions such as Al into a porous powder, and a film-forming coagulant is produced by forming a film made of a water-soluble substance on the surface of the coagulant. A method for producing an inorganic material, comprising a coating step, a mixing step of mixing water glass with the film-forming coagulant to form a mixture, and a molding step of molding the mixture into a desired shape and solidifying it. It is in. (Hereinafter referred to as the second invention.) According to the second invention, the pot life of the mixture can be easily adjusted to a desired length depending on the intended use of the mixture. Other than that, it has the same effects as the first invention.

The second invention will be explained in more detail below.

The second invention adds the above-mentioned coating step to the first invention, and furthermore, materials other than sepiolite and attapulgite can be used as the porous powder in the adsorption step. The coating step according to the present invention is a step of forming a film with a water-soluble substance on the surface of the porous powder impregnated with or adsorbed with multivalent ions in the adsorption step of the first invention.

Specifically, the water-soluble substance is preferably an organic compound such as polyvinyl alcohol, starch, or dextrin, or an inorganic compound such as NaNO ₃ , CaCO ₃ , NaCl, BaCl ₃ , or AlCl ₃ .

As a method for forming the film, it is preferable to form the water-soluble substance into an aqueous solution, immerse the porous powder in the aqueous solution, or spray the porous powder with the aqueous solution, and then dry it. By these methods, a film made of the water-soluble substance can be formed on the surface of the porous powder impregnated with or adsorbed with the multivalent ions, and a film-forming coagulant can be obtained.

Next, the film-forming coagulant is mixed and kneaded with water glass in the same manner as the mixing step in the first invention,
The inorganic material according to the present invention can be obtained by preparing a mixture and subjecting the mixture to a molding process.

When using the film-forming coagulant, multivalent ions are difficult to release into the water glass until the film is dissolved by the water in the water glass, making the pot life 2 to 10 times longer than without the film. be able to.

Similar to the first invention, the pot life can be adjusted by the multivalent ions, the porous powder, and the type and thickness of the coating.

In this case, a mixture of two or more types of porous powders with different coating types, thicknesses, etc. exhibits a special solidification situation than a mixture of a single type of porous powder. This can sometimes prevent strain and cracks from occurring.

The solidified inorganic material has water resistance and heat resistance, and has the same uses as the inorganic material obtained according to the first invention.

In the second invention, in addition to the sepiolite and attapulgite in the first invention, fibers such as montmorillonite, kaolinite, vermiculite, and graphite are used as the porous powder that impregnates or adsorbs multivalent ions in the adsorption step. Powders of porous materials such as shaped or layered materials, zeolites, cristobalite rocks, etc. can be used. Furthermore,
Hollow glass powders with fine pores can also be used.

The layered material such as vermiculite has a layered structure of thin films containing aluminum silicate or the like as a main component.

Furthermore, Cristobal rock and zeolite are granular porous substances containing silicates as a main component, and Cristobal rock in particular has many pores leading to its surface. The diameter of the pores is about 70 Å, and the porosity is about
It is 50%.

Examples according to the present invention will be shown below.

Example 1 100g of Spanish sepiolite powder was added to the tap water in step 1, stirred with a mixer with steel blades, and further added with calcium chloride ( _CaCl2 .
After adding 10g of 6H ₂ O) and thoroughly dissolving it,
I left it for 30 minutes.

This was passed through a Buchner funnel and a suction bottle, and the funnel residue was resuspended in 1 tap water and the residue was washed with water. Thereafter, this water washing operation was repeated 5 times, followed by drying at 80°C for 48 hours, and crushing in an alumina ball mill for 10 hours to obtain sepiolite powder impregnated with or adsorbed with calcium ions as a coagulant according to the present invention. .

Next, 40 g of the coagulant and 200 g of water glass No. 3 (Na ₂ O.2SiO ₂ content: 40 ωt%) were thoroughly mixed to obtain a mixture according to the first invention. The mixture was applied with a spatula to an aluminum plate 10 cm square and 2 mm thick. By drying this at 80°C for 10 hours, a coating film with a thickness of about 0.5 mm was obtained. This coating showed no shrinkage during drying and solidification, nor did it exhibit any cracks or peeling, and adhered well to the aluminum.

Furthermore, the coating film was immersed in warm water at 60°C for 72 hours, but the surface did not dissolve at all.

In addition, the same coating film was heated at 300℃ for 30 minutes,
The coating film exhibited excellent heat resistance without any change in appearance.

On the other hand, when the mixture was applied to the aluminum plate and left at room temperature, it took 24 hours for the mixture to solidify. There are also cracks in the hardened paint film.
There was no peeling from the aluminum plate.

Furthermore, this coating film was immersed in water for a week,
There was no dissolution of the coating film.

As described above, when the mixture was solidified in a high temperature atmosphere, the solidified product had particularly good hot water resistance and heat resistance.

Example 2 Porous cristobalite powder from Aomori Prefecture (100
100g of magnesium nitrate (Mg
(NO ₃ ) ₂・3H ₂ O) mixed with 10 g and 150 g in a crucible.
By heating at ℃ for 20 minutes, magnesium nitrate was impregnated into the pores of the cristobalite powder. After cooling, this was lightly crushed in a mortar. Next, the crushed material was immersed in a 10ωt% aqueous solution of polyvinyl alcohol with a molecular weight of about 500, and immediately passed through a Buchner funnel and a suction bottle, and the residue on the paper was dried at 80°C for 10 hours, and then lightly It was crushed to obtain a powder as a coagulant according to the second invention.

10g of this powder and the same water glass No. 3 as in Example 1.
200g of the mixture was mixed and applied to one side of two foamed glass molded bodies (dimensions: 100 x 50 x 15 mm), and the mixture-applied surfaces were pressed together.

Then, by leaving it at room temperature for 72 hours,
The mixture was dried and solidified, and two foamed glass molded bodies were bonded together.

When applying the mixture to the foam glass molding,
The mixture had not begun to solidify, had the viscosity characteristic of water glass, and had sufficient initial adhesive strength.

Even after the bonded portion of the foamed glass molded product was kept in running tap water for 7 days or at 250°C for 30 minutes, the foamed glass molded product still had an adhesive strength of 3 Kg/cm ² or more, and It has become clear that the mixture is useful as an adhesive having water resistance and heat resistance after solidification.

Comparative example 100g of high-purity montmorillonite powder obtained by removing impurities from Japanese bentonite was added to the tap water in Step 1, and this was stirred with a mixer with steel blades, followed by calcium chloride (CaCl ₂ 6H ₂ O).
After adding 10g of and sufficiently dissolving it, it was left to stand for 30 minutes.

This was filtered using a Buchner funnel and a suction bottle, and the funnel residue was again suspended in tap water from Step 1, and the residue was washed with water. After that, this water washing operation was repeated 5 times, and then dried at 80°C for 48 hours.
It was crushed in an alumina ball mill for 10 hours to obtain montmorillonite powder impregnated with or adsorbed with calcium ions as a coagulant according to the present invention.

Next, 40 g of the coagulant and 200 g of water glass No. 3 (Na ₂ O.2SiO ₂ content: 40 wt%) were thoroughly mixed to obtain a mixture.

About 10 minutes after mixing, the mixture began to coagulate in places. After 1 hour, the coagulated area seemed to have increased, but the whole sample did not coagulate. Even after 72 hours had elapsed, the whole sample did not solidify.

In other words, the coagulant impregnated and adsorbed into montmorillonite was released into the water glass within a short period of time, and the amount of coagulant impregnated was also thought to be small compared to sepiolite. .
Therefore, an aqueous solution of CaCl _{2 was prepared by dissolving 166 g of calcium chloride (CaCl 2 )} as a water glass coagulant in 1 part of water.

1 g of the above aqueous solution was added to 10 g of the above montmorillonite powder, and the mixture was thoroughly mixed in an alumina mortar. The aqueous solution was easily absorbed into the montmorillonite powder and became a homogeneous powder.

An attempt was made to mix 10 g of the powder that had absorbed the above coagulant with 100 g of water glass and place the mixture in a mold. However, solidification started about 10 seconds after the start of mixing, and not only could the mixture not be mixed uniformly as a whole, but it could not be poured into a mold either.

This result shows that the coagulant was released from the montmorillonite within a short time and the water glass was coagulated.

Claims (1)

[Claims] 1. Multivalent ions such as Mg, Ca, Ba, Al, etc. are added to water glass to solidify the water glass,
The method for producing an inorganic material by shaping and solidifying the water glass includes an adsorption step of impregnating or adsorbing the multivalent ions into a porous powder made of one or both of sepiolite and attapulgite to produce a coagulant; A method for producing an inorganic material, comprising a mixing step of mixing water glass with the coagulant to form a mixture, and a molding step of molding the mixture into a desired shape and solidifying it. 2 Adding multivalent ions such as Mg, Ca, Ba, Al, etc. to water glass to solidify the water glass,
The method for producing an inorganic material by molding and solidifying the water glass includes an adsorption step of impregnating or adsorbing the polyvalent ions into a porous powder to produce a coagulant, and adding a water-soluble substance to the surface of the coagulant. A coating process in which a film-forming coagulant is produced by forming a transparent film, a mixing process in which the film-forming coagulant is mixed with water glass to form a mixture, and a molding process in which the mixture is molded into a desired shape and solidified. A method for producing an inorganic material, comprising the steps of: