JPS6019939B2 - Inorganic paint composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel inorganic coating composition that forms a nonflammable coating film with good water resistance and anti-efflorescence properties by drying at room temperature or by baking at a relatively low temperature.

Inorganic paint compositions that use silicate or phosphate as a binder have been known for a long time, but those that use silicate as a binder are prone to efflorescence because the silicate is a strong alkali. It has the disadvantage of poor water resistance, and the biggest drawback is that it deteriorates significantly, especially in hot water.

On the other hand, in the case of inorganic paint compositions that use phosphate as a binder, curing occurs through a chemical reaction involving complex heat generation or heating between the phosphate or curing agent and the substrate to be coated, such as concrete or mortar. Moreover, these chemical reactions are difficult to control and require sophisticated formulation techniques, as these chemical reactions greatly affect the type and proportion of the phosphate and curing agent. Additionally, many inorganic paint compositions that use aqueous colloidal silica as a binder have been proposed, but they are superior to those that use silicate or phosphate as a binder in terms of prevention of efflorescence and water resistance. However, the adhesion and long-term storage properties of the paint film are not as good as those of organic paints, and poor adhesion and performance deterioration due to long-term storage are inevitable.

Therefore, an inorganic coating composition has been proposed in which a synthetic resin emulsion is added and mixed with aqueous colloidal silica to improve the above-mentioned drawbacks.

This product takes advantage of the characteristics of aqueous colloidal silica that it is in an aqueous liquid state under normal conditions and forms a nonflammable continuous film when dried and solidified, and a synthetic resin emulsion is added to this aqueous colloidal silica within a certain range. By adding this additive, the dry gelled silica of aqueous colloidal silica and the dry resin particles of synthetic resin emulsion become entangled without compromising the nonflammability of the coating film, thereby preventing cracking and adhesion of the coating film, which are disadvantages of aqueous colloidal silica. It is said to have improved the bad sex. However, since the synthetic resin emulsion used in this inorganic paint composition is a nonionic or anionic emulsion with 7 to 10 spots, the bonding between the dried gelled silica of the aqueous colloidal silica and the dried resin particles of the synthetic resin emulsion is difficult. Since the bonding strength between the dry silica and the synthetic resin particles is low because they are not chemically entangled but merely physically entangled, they are easily affected by water. Moreover, the dried particles of water-based colloidal silica bond with each other to form a bonded coating film, which tends to create gaps between the bonded particles, and the dry resin particles of synthetic resin emulsion also bond with each other to form a bonded coating film, so water-based Colloidal. The continuous coating film formed from silica and synthetic resin emulsion is not a continuous coating film like general organic resin coatings, but from a microscopic perspective, it has pores and can be easily removed from the substrate to be coated, such as concrete or mortar. Alkaline components tend to appear on the surface of the paint film as scum, causing efflorescence. The inventors of the present invention have conducted various studies in view of such circumstances, and have found that: (1) aqueous colloidal silica, (1) a synthetic resin emulsion with cationic particle charges, {q montmorillonite swelled and dispersed in water, and (2) a viscosity adjusting material. When preparing a paint composition by adding inorganic paint auxiliary materials such as extender pigments, coloring pigments, and aggregate particles, and further adding and mixing (E) water-soluble amino resin if necessary, water resistance is good. It was discovered that an inorganic coating composition capable of forming a nonflammable coating film with anti-efflorescence properties can be obtained, and the present invention was completed.

The reason why the inorganic coating composition of the present invention produces the above-mentioned effects and the process by which the inorganic coating composition of the present invention was completed are as follows.

That is, in aqueous colloidal silica, silanol groups and hydroxyl ions exist on the surface of siloxane bonds, and an electric double layer is formed by these and alkali ions, and is stabilized by electrical antagonism between particles.

Polyvalent metal ions have been known to react with the silanol groups on the surface of the siloxane bonds of this aqueous colloidal silica and anion components of hydroxide ions, dry and solidify to form a coating film, but polyvalent metal ions In this case, the reaction exceeds even during paint storage, so the storage stability of the paint is poor, and since the formed paint film is completely inorganic, it is more likely to crack than an organic resin paint film. Therefore, the present inventors conducted various research in search of a substance that reacts with the silanol groups and hydroxide ions on the surface of the siloxane bonds of aqueous colloidal silica instead of polyvalent metal ions, and as a result, they synthesized particles with cationic charges. Resin emulsion is water-based.

It reacts with the silanol groups and hydroxide ions on the siloxane-bonded surface of idal silica to form a coating film, and the coating film has good adhesion to the substrate, excellent water resistance, and storage stability as a coating material. I found it to be excellent. Synthetic resin emulsions with cationic particle charges as described above react with the silanol groups and hydroxyl ions on the surface of the siloxane bonds of aqueous colloidal silica, but do not react with the silanol groups and hydroxyl ions and dry the aqueous colloidal silica. It has a major difference from the conventionally used pH 7-10 anionic or/ionic synthetic resin emulsion, which is merely physically mixed with silica particles, and as a result, the conventional anionic or nonionic synthetic resin Forms a coating film with much better adhesion and water resistance than when using emulsion.

As mentioned above, inorganic paint compositions made of aqueous colloidal silica and synthetic resin emulsions with cationic particle charges have good storage stability, and in terms of film performance, they have good adhesion, water resistance, alkali resistance, and heat resistance. It has good physical and chemical performance, but since the bond between the water-based colloidal silica and the synthetic resin emulsion in the dry coating is interparticle bonding, from a microscopic perspective, it has fine pores. There is a risk that alkaline components from the base material will appear on the surface of the coating film as scum, causing efflorescence.

Therefore, the present inventors conducted further research and added montmorillonite swollen and dispersed in water to a system containing aqueous colloidal silica and a synthetic resin emulsion with cationic particle charges, thereby preventing the efflorescence phenomenon described above. succeeded in doing so.

That is, when montmorillonite swelled and dispersed in water is added to a system containing aqueous colloidal silica and a synthetic resin emulsion with cationic particle charges, the aqueous colloidal silica and synthetic resin emulsion enter between the layers of montmorillonite, and the cation exchange ability of montmorillonite increases. As a result, montmorillonite reacts with the synthetic resin emulsion that has a cationic particle charge, improving the water resistance of the coating film.At the same time, montmorillonite strengthens the interparticle bonds between the dry silica particles of the aqueous colloidal silica and the dry resin particles of the synthetic resin emulsion. It fills the gaps and forms a continuous coating like a general organic resin coating, so that the alkaline components of the base material do not come out as scum on the surface, that is, a purulent coating is formed that does not cause efflorescence. Furthermore, the present inventors discovered that when adding a water-soluble amide/resin to a system containing water-based colloidal silica, a synthetic resin emulsion having cationic particle charges, and montmorillonite swelled and dispersed in water, as described above, It was also discovered that the silanol groups and hydroxyl ions on the surface of the siloxane bonds of aqueous colloidal silica bond with amino groups, increasing the strength of the coating film and further improving the coating performance.

The aqueous colloidal silica used in the present invention is a colloidal solution in which ultrafine particles of anhydrous silicic acid are dispersed in water using water as dispersed soot. Moreover, the ultrafine particles of silicic acid have a negative surface with silanol groups and hydroxyl ions. A positively charged electrical double layer is formed around the alkali ions, and is stabilized by electrical rebuttal between the particles.

The size of the colloid is 1 to 100 millimicrons. The synthetic resin emulsion with cationic particle charges used in the present invention is made from polymers or copolymers such as vinyl acetate, vinyl chloride, acrylic ester, methacrylic ester, styrene, butadiene, beho/di, ethylene, and urethane. Synthetic resin emulsion is a synthetic resin emulsion made by adding a cationic or cationic/nonionic emulsifier to a synthetic resin that is a single component or a mixture of two or more components, and has a pH in the range of 3 to 6.5. preferable.

The amount of the synthetic resin emulsion having cationic particle charges is 10$ as solid content of aqueous colloidal silica.
Suitable results are obtained when the solid content is in the range of 10 to 85 parts (parts by weight, the same applies hereinafter), and 40 to 6 parts is particularly preferred. If the amount of synthetic resin with cationic particle charges exceeds 85 parts by solid content compared to 10 parts by solid content of aqueous colloidal silica, the coating performance will improve but the non-flammability will decrease. No. 1 Kunifumi is not preferable because the coating performance such as water resistance and chemical resistance deteriorates. Generally, as the organic mass in an inorganic coating composition increases, the nonflammability performance decreases, but in the inorganic coating composition of the present invention, as mentioned above, the solid content of the aqueous colloidal silica is 10 parts, while the solid content of the synthetic resin emulsion is Even if it is added up to 85 parts, the nonflammability does not decrease.

This is thought to be due to the fact that when the aqueous colloidal silica and synthetic resin emulsion are dried and solidified, the organic matter is pulled towards the inorganic side due to the reaction between the inorganic matter and the organic matter, thereby improving the nonflammability. In fact, even in paint film combustion tests, no paint blisters or cracks occur, and the amount of smoke generated is low.
According to experiments conducted by the present inventors, the amount of the synthetic resin emulsion with cationic particle charges was 85% in terms of solid content.
It has been found that even if the organic mass exceeds 40% (by weight, hereinafter the same) in the solid content of the coating composition, the nonflammability does not deteriorate.

The montmorillonite used in the present invention is the main component of pentonite, and is highly purified sodium montmorillonite extracted from natural swelling clay pentonite through physical and chemical processes.

Sodium montmorillonite not only has a bee-preventing effect and a viscosity-increasing effect, but also has plate-shaped particles that are arranged in a fixed direction and has a film-forming ability. By adding this montmorillonite to a system containing aqueous colloidal silica and a synthetic resin emulsion with cationic particle charges, it not only exhibits an anti-settling effect and a thickening effect, but also has a strong effect during coating film formation. The ability to form a coating film is exhibited, and the occurrence of cracks in the coating film is prevented. In addition, montmorillonite incorporates bonded particles of water-based colloidal silica and synthetic resin emulsion between its layers, making the coating dense and suppressing the action of water on the base material. Prevents bloom phenomenon. In the present invention, montmorillonite is used in a swollen and dispersed state in water.

The dispersion of montmorillonite into water is preferably carried out under high-speed shearing force. The amount of montmorillonite used is 1 to 1 in solids per 10$ of aqueous colloidal silica.
Favorable results are obtained with a range of 0 parts, and a range of 4 to 8 parts is particularly preferred. If the amount of montmorillonite used is less than 1 part by solid content compared to 10 parts by solid content of aqueous colloidal silica, film forming properties will be poor and the coating film will be likely to crack.
On the other hand, if it exceeds 1 part, the coating film becomes soft and the strength of the coating film decreases, which is not preferable. In the present invention, the water-soluble amino resin is a water-soluble amino resin such as melamine resin, urea resin, urea-melamine resin, gufnamine resin, etc., and is provided in the form of a resin liquid dissolved in an organic solvent. Preferably.

As for the amount of water-soluble amino resin added, preferable results are obtained in the range of 1 to 2 parts of solids per 10 parts of solids of aqueous colloidal silica, and particularly preferably in the range of 5 to 15 parts. The amount of water-soluble amino resin added is 1 part by solid content per 10 parts by solid content of water-based colloidal silica.
If the amount is less than 2 parts, the effect of adding the water-soluble amino/resin will not be sufficiently exhibited, and if it exceeds 2 parts, the amount of water droplets will increase, making the coating film more susceptible to efflorescence. In preparing the inorganic coating composition of the present invention, auxiliary materials for inorganic coatings, such as viscosity modifiers, extender pigments, coloring pigments, aggregate particles, etc., are added in addition to the above-mentioned components. For example, sodium polyacrylate, methyl cellulose, etc. are used as viscosity adjusting materials, and these have the same function as viscosity adjusting agents.

It works to improve the film-forming effect of night. Extender pigments are preferably ones that do not contain heavy metals as much as possible, such as talc, mica, lotus clay, and asbestos.
In particular, flake-like or fibrous materials are preferable because they have a great effect of preventing cracks in the coating film.

Preferably, the coloring pigment is one that does not contain heavy metals, such as titanium oxide, iron black, chromium oxide, red iron oxide, cobalt blue, or an inorganic fired pigment.

As the aggregate grains, for example, silica sand grains, cold water sand grains, etc. are preferable.

These paint auxiliary materials, such as viscosity adjusting materials, extender pigments, coloring pigments, aggregate particles, etc., are not all required at the same time, but are selected appropriately depending on the application of the paint, and are used to improve the composition of the paint composition. It is appropriately blended within a range that does not impair the properties.

The inorganic coating composition of the present invention prepared as described above can be applied to asbestos slate boards, mortar, concrete, gypsum plus coating, etc. by appropriate coating methods such as brush coating, roll brush coating, air spray coating, and airless spray coating. , gypsum boards, earthen walls, stones, calcium silicate boards, wood, plywood, particle boards, artificial lightweight materials molded with organic synthetic resins, inorganic clay, etc., steel frames, aluminum, and those painted with organic paints. It forms a non-flammable coating film with good water resistance and anti-efflorescence properties by drying at room temperature or by agglomeration at a relatively low temperature of about 60 to 80 qo. .

Next, the present invention will be explained with reference to Examples.

Example 1 An inorganic coating composition having the following composition was prepared.

Aqueous colloidal silica 10 parts (solid content 30%) cationic particle charge at pH 4
Acrylic resin emulsion containing 35 parts (solids content 40
%) 6% Mont Mori.

Night 3 parts Water swelling dispersion 5% Methyl cellulose 2 parts Water swelling dispersion Mica 25 parts Pengara 5 parts This inorganic paint composition was dried on an asbestos slate board for 250 days.
The coated plate was prepared by coating it so as to give a perfect finish and drying at 20 qo for 7 days, and the test results shown in Table 1 were obtained.

The 6% montmorillonite water-swollen dispersion was prepared by adding montmorillonite little by little into a predetermined amount of water at a high circumferential speed of 2,000 times/second and causing it to swell. After adding a fixed amount, the montmorillonite was further swelled for 3 minutes to completely swell the montmorillonite. Example 2 An inorganic coating composition having the following composition was prepared.

Aqueous colloidal silica 10 Ikarito (solid content 30%) Cationic particle charge at pH 4
Acrylic resin emulsion with 4 anchors (solid content 4
0%) 6% Montmorillonite 25 parts Water-swollen dispersion 5% Methylcellulose 2 parts Water-swellable dispersion Mica 25 parts Pengara 5 Kato Water-soluble melamine resin 4 parts (solid content 80%) The above coating composition was applied to an asbestos slate board. A coated plate was prepared by painting in the same manner as in Example 1, and the test results shown in Table 1 were obtained.

Table 1 (Note) The test method is as follows.

Storage stability: According to JISK 54009.2.

Workability: JISK 54005. The arms will be painted with U hair. Pencil drag value...JISK 54006.1
According to 4.

Heat resistance: 5 according to JIS K Hiroshi 007.1
Set to 0000.

Woven water resistance: according to JISK 54007.3.

Water resistance: 7 according to JISK 54007.2
Daily immersion alkali resistance...JISK 56635.
12, 7-day immersion adhesion...JISA 6
According to 9095.5.

Film resistance: 6 according to JISK 54009.2
Monthly exposure Flammability: Irradiate the paint film with the flame of an alcohol lamp for 15 minutes.

In addition, in the water resistance, alkali resistance, and weather resistance tests, "no abnormalities" also means that there is no efflorescence phenomenon.

Examples 3 to 7 and Comparative Examples 1 to 7 Inorganic coating compositions having the compositions shown in Table 2 were prepared,
A coated plate was prepared in the same manner as in Example 1, and the same tests as in Example 1 were conducted.

The results are shown in Table 3. Table 2 Table 3

Claims (1)

[Claims] 1 (A) aqueous colloidal silica, (B) a synthetic resin emulsion having cationic particle charges, (C) montmorillonite swelled and dispersed in water, and (D) a viscosity adjusting material, an extender pigment, It consists of inorganic paint auxiliary materials such as color pigments and aggregate particles, and the solid content of component (B) is 10 to 85 parts by weight per 100 parts by weight of solid content of component (A), and (C)
An inorganic coating composition characterized in that the solid content of the components is present in an amount of 1 to 10 parts by weight. 2 (A) aqueous colloidal silica, (B) synthetic resin emulsion with cationic particle charges, (C) montmorillonite swelled and dispersed in water, (D) viscosity modifier,
It consists of inorganic paint auxiliary materials such as extender pigments, coloring pigments, and aggregate particles, and (E) a water-soluble amino resin, and the solid content of component (B) is 10 to 10 parts by weight per 100 parts by weight of the solid content of component (A).
85 parts by weight, a solid content of component (C) of 1 to 10 parts by weight, and a solid content of component (E) of 1 to 20 parts by weight.