JPS5835631B2 - Inorganic adhesive composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to an inorganic adhesive composition.

In recent years, as buildings have become taller and underground malls have expanded, various non-combustible building materials and fire-resistant covering materials have been used to prevent fires.
Fire-resistant, non-combustible adhesives are required in the manufacture or construction of these materials.

Water glass adhesives are conventionally known as nonflammable adhesives, but these are made only of water glass and aggregate, and therefore harden slowly and develop initial strength slowly.

Furthermore, it is not water resistant, so it cannot be used in humid basements, areas prone to condensation, or areas where water is used.

Furthermore, at high temperatures of 600° C. or higher, the water glass softens, resulting in disadvantages such as a decrease in adhesive strength.

Various adhesive compositions that use curing agents in combination have been proposed to improve these drawbacks, but all of these have problems in the balance between pot life and curing time. If removed, curing will be insufficient, resulting in loss of water resistance and efflorescence.

Furthermore, if hardening is attempted in a short period of time, the pot life will be significantly shortened, resulting in problems with workability.

In order to have an appropriate pot life and complete curing, heat treatment is required after adhesion, which makes on-site construction difficult, which poses limitations in terms of use.

The present applicant had previously proposed a water glass-based inorganic composition containing a curing agent that exhibits excellent water resistance in a reaction curing system at room temperature and does not cause alkali carbonate leaching (Japanese Patent Application No. 52-134).
No. 367), the present inventor used a composition consisting of the above-mentioned curing agent and an aqueous silicate solution or hydrated silicate powder, and added anhydrous alkali silicate powder and an inorganic filler to the composition to obtain a suitable usable material. It is possible to obtain an adhesive that has a long time, quickly develops adhesive strength at room temperature, increases strength over a long period of time, improves water resistance, and has excellent water resistance and does not suffer from the Nikka phenomenon. Furthermore, it was discovered that by adding a polyhydric alcohol or a resin emulsion to this adhesive, an adhesive with an extended open time after application could be obtained, and the present invention was completed based on this finding.

That is, the present invention consists of the following four components: (I) 100 parts by weight of an aqueous silicate solution or hydrous silicate powder (as a pure component) (II)
) Curing agents 30 to 30 consisting of the following components a) to (d)
0 parts by weight (a) Calcium sulfite and/or calcium thiosulfate 100 parts by weight (b) Calcium silicate 50 to 300 parts by weight (c) Zinc oxide 0 to 300 parts by weight (d) Aluminum hydroxide, alumina, hydrated alumina One or more aluminum compounds selected from 0-
150 parts by weight (7) Alkali silicate powder 10-10
0 parts by weight (g) Inorganic filler 100 to 1000 parts by weight and upper = a I) - (0 to 8 based on the total amount of ~ components)
This is an inorganic adhesive composition characterized by containing a polyhydric alcohol (% by weight) and/or a resin emulsion (solid content).

The silicate as component (I) used in the present invention is preferably an aqueous solution or hydrous silicate powder, or an alkali metal silicate such as sodium, potassium, or lithium, and these are 8102/M20 (M is It is used as an aqueous solution having a molar ratio of 1.5 to 4.5 (alkali metal) and a concentration of 10 to 50% by weight, or as a hydrous silicate powder containing 10 to 30% by weight of water.

Hydrous silicate is a solid obtained as an intermediate in the transition from anhydrous silicate to liquid silicate, and in the present invention, the 5i02/M20 molar ratio is 1.5 to 4.
5. Moisture content 10-30% by weight, preferably 15-25%
% by weight powder is preferable.

If the molar ratio is less than 1.5, it is highly hygroscopic and difficult to powder and store; if the molar ratio is more than 4.5,
This is not preferable because the solubility in water becomes poor.

Further, if the water content is less than 1.0% by weight, the dissolution rate in water is extremely slow and is impractical, and if it exceeds 30% by weight, the powder itself becomes sticky and tends to cause blocking, which is not preferable.

In addition, the average particle size of the powder is preferably 400 μm or less from the viewpoint of miscibility with hardening agents and the like.

As the hardening agent component (1), a mixed hardening agent of calcium sulfite, calcium thiosulfate, and calcium silicate is used. An aluminum compound may also be blended.

The appropriate composition ratio of the curing agent is 50 to 300 parts by weight of calcium silicate, 0 to 300 parts by weight of zinc oxide, and 0 to 150 parts by weight of the aluminum compound per 100 parts by weight of calcium sulfite and/or calcium thiosulfate. be.

In the curing agent of the present invention, calcium sulfite, calcium thiosulfate, and calcium silicate are essential components, but
The lack of these components significantly slows down the curing speed, deteriorates water resistance, and causes poor curing at room temperature, making it impossible to work on-site.

Among these components, calcium sulfite is industrially advantageous because it can be used to remove insects and absorb waste sediment from flue gas desulfurization using slaked lime.

Further, the blending of zinc oxide improves the strength, and the blending of an aluminum compound is effective in reducing the shrinkage rate during curing and suppressing the occurrence of cracks.

The blending amount of the curing agent is 30 to 300 parts by weight (as pure content) based on the silicate aqueous solution or hydrous silicate powder ioo parts by weight.
Parts by weight are appropriate.

If the amount of curing agent is less than 30 parts by weight, curing failure will occur and adhesive strength will be significantly reduced.

In addition, water resistance is also impaired and a sunflower phenomenon occurs.

If the amount of curing agent exceeds 300 parts by weight, the pot life will be significantly shortened and workability will deteriorate, which is not preferable.

The addition of anhydrous alkali silicate powder, which is the component (e) in the adhesive composition of the present invention, improves the initial reaction rate as an adhesive and promotes the reaction with the curing agent component and filler at high temperatures, thereby improving fire resistance. It's about improvement.

Although this mechanism has not yet been elucidated, it is thought that it acts as an alkaline stimulant and promotes the reaction.

Such anhydrous alkali silicate powder is obtained by pulverizing silicates of alkali metals such as sodium, potassium, and lithium, and has a particle size of 500μ or less, preferably 2.
00μ or less and a 5i02/M20 molar ratio of 1.5 to 4.5 is preferably used.

If the molar ratio is less than 1.5, the pot life as an adhesive will be shortened, and water resistance, fire resistance, etc. will also be reduced.

Furthermore, if the molar ratio exceeds 4.5, the accelerating effect as an alkali stimulant will be poor and the fire resistance after adhesion will be reduced, so the choice should be made depending on the intended use.

When the particle size of the powder exceeds 500 μm, the reactivity decreases, making it difficult to obtain sufficient initial strength, and it is also difficult to obtain satisfactory results in water resistance and fire resistance.

The appropriate amount of the anhydrous alkali silicate powder is 10 to 100 parts by weight based on 100 parts by weight (as pure content) of the aqueous silicate solution or hydrous silicate powder.

If the amount is less than 10 parts by weight, the effect of promoting the reaction is poor and the effect of developing initial adhesive strength is small.

Moreover, if it exceeds 100 parts by weight, the pot life will be significantly shortened and it will be impractical.

Examples of inorganic fillers that are components of the present invention include silica sand, clay, calcium carbonate, talc, bentonite, diatomaceous earth, kaolin, pearlite, shirasu balloon, vermiculite powder, and glass powder, and the particle size thereof is In terms of performance as an adhesive, the thickness is preferably 500μ or less.

The blending amount is silicate aqueous solution or hydrous silicate powder 100%
It is 100 to 1000 parts by weight based on the weight part (as pure content).

The inorganic filler is effective in preventing curing shrinkage of the adhesive and improving its strength.

If it is less than 100 parts by weight, the effect is small;
If the amount exceeds 1 part by weight, the strength will drop significantly, which is not preferable.

A polyhydric alcohol or a resin emulsion may be added to the adhesive composition of the present invention, if necessary.

Normally, water glass adhesives form a thin film on the surface due to water evaporation even within the pot life after application, and as a result, adhesive strength may decrease.

Therefore, it is difficult to take a long time (so-called open time) between applying the adhesive and bonding.

In the present invention, the above open time can be extended by adding a polyhydric alcohol or a resin emulsion.

Typical examples of such polyhydric alcohols include ethylene glycol, propylene glycol, and glycerin, and examples of resin emulsions include acrylic,
Examples include styrene-acrylic, styrene-butadiene, and ethylene-vinyl acetate.

The resin content of the resin emulsion is suitably 20 to 50% by weight.

The above-mentioned polyhydric alcohols and/or resin emulsions may be used alone or as a mixture, and the amount of polyhydric alcohols and/or resin emulsions (solid minutes) 8
It is appropriate that the amount is less than % by weight.

If the blending amount exceeds 8% by weight, water resistance and fire resistance will drop significantly, which is not preferable.

The adhesive composition of the present invention may further contain an inorganic fiber as a reinforcing agent or a thickener, if necessary.

Examples of inorganic materials include asbestos, rock wool, ceramic materials, and glass materials, which are effective in preventing wetting, preventing cranking, and improving strength.

Thickeners include methylcellulose, carboxymethylcellulose, polyacrylic acid, sodium polyacrylate,
Examples include polyethylene oxide and polyvinyl alcohol, which are effective in improving workability through moderate viscosity and preventing sedimentation and separation of adhesive components.

Since the adhesive of the present invention is of a reactive curing type, when an aqueous silicate solution is used, it must be stored separately from the curing agent and mixed with it at the time of use.

Since the anhydrous alkali silicate powder dissolves in the silicate aqueous solution, it is best to mix it with a hardening agent, and the inorganic filler
It may also be mixed with a hardening agent and anhydrous alkali silicate powder (
may be mixed with an aqueous silicate solution.

Further, the polyhydric alcohol or resin emulsion as a modifier may be mixed with the silicate aqueous solution, or may be added and mixed at the time of use.

Further, when using a hydrous silicate powder, it is extremely advantageous because it can be mixed with a hardening agent and stored, and it can be easily applied on-site by adding an appropriate amount of water at the time of use.

Substrates to which the adhesive of the present invention is applied include various substrates such as asbestos slate boards, pulp cement boards, calcium silicate boards, gypsum boards, refractory bricks, ALC boards, iron boards, aluminum boards, and synthetic boards.

The present invention will be explained below with reference to Examples.

In each example, parts and % represent parts by weight and % by weight, respectively.

Examples 1 to 5, Comparative Examples 1 to 3 A hardening agent consisting of 50 parts of calcium sulfite, 50 parts of calcium silicate, 25 parts of zinc oxide, and 25 parts of aluminum hydroxide and anhydrous alkali silicate powder shown in Table 1 (particle size 200
μ or less) and calcium carbonate (Maruo Calcium Co., Ltd. “0
98 heavy carbon 1) was mixed for 15 minutes using a universal mixer to prepare a curing mixture.

To this was added 250P of an aqueous solution of IJ (molar ratio 3.2, concentration 40%) and kneaded for 2 minutes using a lab mixer to obtain each adhesive.

Glue two asbestos slate boards together using the above adhesive,
Compressive shear strength was measured according to JIS K 6852.

Apply the above adhesive with a 0.52 spatula to a size of 25 x 25 nm from the edge of one side of an asbestos slate plate (25 x 30 x 5 mm), and stack asbestos slate plates of the same shape as above on top of this so that the non-adhesive parts are on both ends. After adhesion** and a predetermined curing period, the compressive shear strength was measured, and the results are shown in Table 1.

Comparative Example 3 used 50 parts of thorium silicofluoride as a hardening agent, mixed with 400 parts of calcium carbonate.

Examples 6 to 9, Comparative Example 4.5 A curing agent consisting of 50 parts of calcium sulfite, 30 parts of calcium silicate, and 30 parts of zinc oxide, anhydrous alkali silicate powder (particle size of 200 μm or less) shown in Table 2, and hydrous silica Salt powder (
Each adhesive composition was prepared by mixing (particle size of 400 μm or less) and calcium carbonate in a universal mixer for 15 minutes.

To this was added water in the amount shown in Table 2 and kneaded at room temperature to obtain an adhesive.

Using the obtained adhesive, the compressive shear strength was measured in the same manner as in Examples 1 to 5, and the results are shown in Table 2.

Examples 10 to 12, Comparative Example 6.7 Using the adhesive compositions of Examples 1 and 6, polyhydric alcohols or resin emulsions shown in Table 3 were added to the adhesive compositions at an open time of 0. The compressive shear strength was measured by the same test method as in Examples 1 to 5 at 30 minutes and 30 minutes,
The results are shown in Table 3.

Claims (1)

[Claims] 1 (■) Aqueous silicate solution or hydrous silicate powder (as pure content) 100 parts by weight (1) Lower 1
30 to 300 parts by weight of a curing agent consisting of components da)-('d) 10 to 100 parts by weight of anhydrous alkali silicate powder (5)
100 to 1000 parts by weight of an inorganic filler and the above (I
)-(An inorganic adhesive composition characterized by containing 0 to 8% by weight of polyhydric alcohols and/or resin emulsion (solid content) based on the total amount of IM components. (a) Calcium sulfite and/or or calcium thiosulfate 100 parts by weight (b)
Calcium silicate 50-300 parts by weight (c)
Zinc oxide 0-300 parts by weight (d)
One or more aluminum compounds selected from aluminum hydroxide, alumina, and hydrated alumina
O~150 parts by weight