JPS62290765A - Inorganic paint - Google Patents

Abstract

PURPOSE:To improve film performances such as adhesion, resistance to water and heat, etc., to prolong pot life and to improve workability, etc., by incorporating an inorg. ion exchange material having an OH group in an inorg. paint. CONSTITUTION:An inorg. ion exchange material having an OH group in its structure (e.g., zirconium phosphate, hydrotalcite) is incorporated in inorg. paint. The inorg. ion exchange material functions as a curing agent so that part or the whole of a curing agent in the inorg. paint can be replaced with said material to adjust its pot life. Further, ions constituting salts originating from the curing agent in the paint can be captured by said ion exchange material so that water resistance can be improved. Alkali or alkaline earth metal components migrating from the inside of a substrate to be coated, toward its coating film can be captured by said material and fixed so that the adhesion of the film can be improved.

Description

[Detailed description of the invention] 3. Detailed description of the invention (1) Purpose of the invention [Industrial application field] This invention disperses and/or melts inorganic substances in water,
This applies to so-called inorganic paints that form a film when this water evaporates, or harden by reacting with the water itself. It has improved performance and prevents corrosion of the base phase on the coated surface.

[Conventional technology]

Inorganic paints include lime milk paint, which is a mixture of lime milk and pigments;
Silicate paints are made by mixing pigments into an aqueous solution of sodium silicate or potassium silicate, and colloidal silica (aqueous silica sol) is made by polymerizing only silicic acid to the size of colloidal particles by removing the soda content of sodium silicate. ) and alumina sol, which is an aqueous dispersion of fibrous alumina with the size of colloidal particles and has a chemical composition intermediate between an aqueous aluminum chloride solution and an aluminum hydroxide powder.

These inorganic paints differ from general organic paints in that they are non-flammable, smokeless, solvent-free, odorless, etc., and cause almost no pollution problems; they also have heat resistance, hardness, abrasion resistance, oil resistance,
It also has excellent solvent resistance.

However, on the other hand, inorganic paints have poor adhesion and are prone to cracking and peeling even after painting, and organic paints have poor water resistance, weather resistance, short pot life, and poor workability. It's inferior in comparison.

In inorganic paints using silicate, salts such as aluminum phosphate, magnesium phosphate or magnesium carbonate are used as hardening agents, but after curing, water-soluble salts such as alkali phosphates and alkali carbonates are added to the composition. As a result, the resulting coating film generally had poor water resistance and weather resistance, was softened by water, resulting in blistering and peeling, and was susceptible to deterioration due to carbonation due to carbon dioxide gas in the air.

As an improvement method for improving the water resistance of a coating film, for example, a method has been attempted in which a water-soluble silicate aqueous solution is applied to a substrate and then a curing agent is sprayed onto the substrate.

Also, proposals have been made to use lithium in the same alkali instead of soda or potash, or paints using amines.

The use of lithium produces non-water-absorbing coatings with relatively good water resistance, while the use of amines produces water-resistant coatings that give a soft illusion somewhat similar to organic resins.

However, even the coating film obtained in this manner still has insufficient water resistance and poor weather resistance, and the coating film surface may sometimes turn white when subjected to a weather resistance test.

Inorganic compositions using colloidal silica as a vehicle have excellent water resistance and weather resistance because they do not contain alkaline components, but they have poor film forming properties and are brittle, so they are prone to cracking. Colloidal silica tends to lose its surface charge balance, causing aggregation reactions and gelling.

If it gels, it will naturally become unusable as a paint.

In order to improve this drawback, a composition composed of colloidal silica stabilized with lithium ions and finely divided metallic zinc powder has been proposed, but even with this composition, the water resistance of the dried paint film is poor. It is not sufficient, and the paint film tends to soften in areas immersed in water.

Similarly, lime milk paints and alumina sol have problems in water resistance and weather resistance.

In recent years, silicon ethoxide,
Metal alkoxide paints such as titanium isopropoxide have been used, but since these use chloride as the starting material and use acids such as hydrochloric acid for curing, chloride ions remain in the paint film, which causes It often migrates to the interface with materials, causing corrosion of the base material and peeling of the paint film.

Apart from this, there is also the problem of corrosion of the base material caused by ionic substances such as alkalis and halogens generally contained in inorganic paints.

[Problem that the invention seeks to solve]

As mentioned above, conventional inorganic paints have problems with film performance, such as water resistance, weather resistance, and adhesion, and also have short pot life when mixed with a hardening agent, resulting in poor workability. There was also.

On the other hand, corrosion of the base material by inorganic paints is also a problem.

Inorganic paints take advantage of their characteristics and are used for corrosion protection of ships and iron structures, paint materials for the interior and exterior of buildings, decorative building materials, heat-resistant paints, etc. However, these drawbacks have limited the scope of their use.

(2) Structure of the invention [Means for solving the problems] The present invention solves the above problems by incorporating an inorganic ion exchange material having -OH groups in the constituent components into an inorganic paint. This is the solution.

[Effect]

The first reason why coating film performance is improved by adding an inorganic ion-exchangeable substance to an inorganic paint is that the inorganic ion-exchangeable substance also functions as a hardening agent. This is because part or all of the material can be replaced, and thereby the pot life can be adjusted.

Inorganic ion exchange substances undergo an ion exchange reaction with ions in the inorganic paint, but the ion exchange rate of inorganic ion exchange substances generally varies depending on the type, properties of the composition, reaction temperature conditions, etc. In other words, the reaction is slower than the neutralization reaction in conventional curing agents, so as the ion exchange reaction progresses, curing progresses gradually.

Furthermore, by appropriately adjusting the curing speed by adjusting the amount and type of inorganic ion-exchangeable substance, it is possible to obtain a pot life that suits the usage conditions and application. There is no chemical reaction.

As mentioned above, the coating film of inorganic paints can be cured gradually using an ion-exchange material, resulting in a dense coating film with little distortion, and can prevent cracking and peeling. .

The second reason why the coating performance improves in the present invention is that when a normal curing agent is used, salt remains in the cured product after curing, which is one of the major causes of poor water resistance. However, when an inorganic ion exchange material is used, the ions constituting the salt are captured by the inorganic ion exchange material, and even when immersed in water, there is very little elution of the salt, resulting in improved water resistance.

Further, according to the present invention, the adhesion to the substrate is significantly improved compared to conventional inorganic paints.

In other words, in conventional inorganic paints, if the base material contains alkali or alkaline earth components, these components may react with the coating film components, reducing the strength of the coating film or gradually decomposing the coating film. The adhesion between the coating film and the substrate deteriorates, and defects such as peeling of the coating film may occur.

However, the inorganic paint containing the inorganic ion-exchangeable substance of the present invention captures and fixes the alkali and alkaline earth components that migrate from within the base material, suppressing the above reactions and decomposition, and improving the adhesion of the paint film. It will improve.

Regarding the problem of corrosion, by including an inorganic ion-exchange material in an inorganic paint, ionic impurities within the paint film are captured, making it possible to prevent corrosion of base materials such as metals and concrete.

In the present invention, inorganic paints containing anionic impurities such as halogens contain an inorganic anion exchange material, and inorganic paints containing cationic impurities such as alkalis contain an inorganic ion exchange material. That's fine. Of course, both may be contained during opening.

[Inorganic paint]

As mentioned above, the inorganic paint used in the present invention is one that disperses and/or dissolves an inorganic substance in water and forms a film when the water evaporates, or hardens by reacting with the water itself. Any type of paint may be used, but silicate paint is preferred because of its excellent modification effect.

[Inorganic ion exchange material]

The inorganic ion-exchangeable substance used in the present invention can be a cation-exchangeable substance, an anion-exchangeable substance, or an anion-exchangeable substance, as long as it has a =〇1■ group in its constituent components and has an ion-exchange ability. It may be any amphoteric ion-exchangeable substance, or it may be a composite or a mixture containing two or more metal elements.

Such inorganic/ion exchange substances include polyvalent metal acids such as antimonic acid, niobic acid, manganic acid, bismuth acid, stannic acid, titanic acid, and zirconic acid, and their salts, zirconium phosphate, titanium phosphate, and phosphoric acid. Polyvalent metal polybasic acid salts such as tin, cerium phosphate, tin arsenate, and titanium arsenate, heteropolyacids such as molybdic acid and tungstic acid, and their salts, hydrotalunites, avatarite, etc. .

Among the various inorganic ion exchange materials mentioned above, antimonic acid, zirconium phosphate, and titanium phosphate have excellent water resistance and chemical resistance, and have good scavenging properties for sodium, potassium, and calcium, and bismuth acid and hydrotalcite , hydroxyapatite is preferred because it has excellent water resistance and chemical resistance, and has good halogen scavenging properties.

The use of such inorganic ion-exchangeable substances is determined by the type and amount of ions to be captured that migrate from inside or outside the inorganic paint, and the balance with other physical properties of the inorganic paint, but usually the use of the inorganic paint as a whole The mixing ratio is 0.1 to 20
A weight percent is preferable, and a weight percent of 1.0 to 10 percent is particularly preferable.

If the amount is too small, it will not be possible to capture and fix the ionic impurities, and adding too much will affect the original physical properties of the composition and is also economically undesirable.

As a method for mixing the inorganic ion-exchangeable substance into the inorganic paint, a conventional stirrer, sieve, kneader, roll, etc. can be used.

[Examples and comparative examples]

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In the examples, "%" means "% by weight" and "part" means "rmff1 part".

Example 1 and Comparative Example 1 40 parts of potassium silicate aqueous solution (30% in terms of Si02), 30 parts of sodium silicate aqueous solution (30% in terms of Si02), 10 parts of quartz sand, 10 parts of titanium white, and 10 parts of zinc white. A mixed mixture was obtained.

Separately, zirconium carbonate was added to concentrated phosphoric acid, heated under reflux for 96 hours, then filtered, washed with water, dried, and ground to obtain zirconium phosphate powder.

An inorganic paint obtained by adding and mixing 5 parts of zirconium phosphate to 100 parts of the above mixture was spray-painted onto a steel plate and dried at room temperature for one week (Example 1).

Comparative Example 1 was obtained by adding 5 parts of magnesium carbonate instead of zirconium phosphate and performing the same treatment.

Table 1 shows the performance evaluation test results of the coating films obtained in Example 1 and Comparative Example 1.

Table 1 However, each evaluation test was conducted under the following conditions.

Adhesion = IIIl x IIIm grid test Water resistance: 250 hours immersion in water at 20°C Weather resistance: Weatherometer (registered trademark) 500 hours
(JIS K-5400-6-16) Boiling water resistance: 100
℃, boiled for 2 hours Surface whitening: 20℃, 165% R11, left for 720 hours Comparative Example 1 gelled 15 minutes after mixing and became unusable as a paint, but Example 1 remained unchanged even after 48 hours. It had turned into a gel.

Compared to coatings obtained by conventional methods, the coatings obtained by the present invention are extremely superior.

Example 2 and Comparative Example 2 Antimony pentachloride was added to 90'C hot water and hydrolyzed, then filtered, washed, dried and pulverized.
A hydrated antimony pentoxide powder was obtained.

Corondarsili fluid (25% in terms of Si02) 5
0 parts, 35 parts of quartz sand, 10 parts of zinc white, 5 parts of titanium white,
An inorganic paint was obtained by mixing 5 parts of the above hydrated antimony pentoxide.

This was spray-painted onto a slate board and dried at room temperature for 10 minutes (Example 2).

Comparative Example 2 was obtained by performing the same treatment without adding hydrated antimony pentoxide.

The performance evaluation test results of Example 2 and Comparative Example 2 are shown in Table 2.

Table 2 However, each evaluation test was conducted under the following conditions.

Adhesion, water resistance, 16 resistance 2 Same as Example 1 Curing properties: Pencil hardness As is clear from Table 2, the performance of the coating film obtained in the present invention is excellent.

(3) Young fruits of the invention The inorganic paint according to the invention has excellent coating performance such as water resistance, weather resistance, and adhesion, and also has excellent workability because it can extend its pot life. There is.

Furthermore, since it adsorbs ionic impurities in the paint or ionic impurities that enter from outside the system, it also prevents corrosion of the base material.

Therefore, the range of use of these inorganic paints, which had been limited in the past, will be further expanded.

Claims (1)

[Claims] 1. An inorganic paint containing an inorganic ion exchange material having an -OH group in its constituent components.