KR0130019B1 - Normal temperature-curable inorganic coating compositions - Google Patents

Abstract

The inorganic coating composition comprises a main material and a curing agent. The main material contains 10-50 wt.% of an adhesive which consists of not only silicate or modified silicate but also soluble amorphous silica or colloidal silica to increase the ratio of silicate (SiO2/Na2O) to 2.8-7.03, 20-80 wt.% of a pigment such as mica, talc and wallastonite, 10-50 wt.% of an inorganic pigment and 5-30 wt.% of distilled or purified water. The curing agent contains 20-80 wt.% of phosphoric compounds and their composite salts, 5-50 wt.% of zinc dust or aluminium dust and 20-60 wt.% of distilled water.

Description

Room temperature curing type inorganic coating composition

The present invention relates to a room temperature-curable inorganic coating composition, and more particularly, to a room temperature-curable inorganic coating composition capable of forming a coating film by heating at room temperature without being heated and cured after being coated on a base metal and metal substrate. It is about.

Conventionally, as disclosed in Korean Patent Publication No. 91-6387, a strong coating film was formed through a polycondensation reaction of a silicate and a phosphate compound, which required heat curing of 200 ° C. or higher.

Accordingly, the present invention is to provide a two-component reactive room temperature drying inorganic coating composition using a silicate or a modified silicate as a colorant and a complex salt of an oxide, hydroxide, calcium / strontium, and zinc of a polyvalent metal as a curing agent. In particular, the binder in the inorganic coating composition was dissolved in soluble amorphous silica or soluble amorphous silica compound or colloidal silica in the silicate or the modified silicate silicate to increase the molar ratio (SiO ₂ / M ₂ O) of the silicate to 2.8 to 7.03. It is an object of the present invention to provide an inorganic coating composition having excellent heat resistance and corrosion resistance.

The room temperature-curable inorganic coating composition that achieves the object of the present invention is composed of a main body and a curing agent, using a silicate, modified silicate, such as amorphous silica, amorphous silica compound or clodal silica to molar ratio of the colorant to 2.8 ~ 7.03 The main material produced by applying an inorganic pigment, MICA, Talc, wollastonite, zeolite and distilled water thereto; Aluminum triphosphate, aluminum metaphosphate, calcium strontium zinc phosphosilicate, barium sulfate, aluminum silicate, magnesium phosphate, calcium silicate, zinc dust or / and a hardener made by applying aluminum dust and water. The objective of the present invention is achieved by mixing the coating agent with the curing agent in the field.

In the present invention, the manufacturing process of the subject will be described in more detail as follows.

The silicate which can be used by this invention is represented by following General formula (1).

_{nM 2 O · mSiO 2 · xH} 2 O --------------------- (1)

Here, n, m, and x are coefficients, and M is an alkali metal belonging to group 1A of the periodic table and is lithium, sodium, potassium, ammonium, or the like.

The silicate is preferably selected and used in consideration of the properties of the composition and the physical properties of the coating film. To obtain a water-resistant coating film, potassium, lithium or ammonium salts are required, and sodium salt is necessary when it is necessary to increase adhesion. This is a known fact. In the present invention, by increasing the silicate to 2.8 ~ 7.03 molar ratio to make the bond of Si-O-Si densely, the stability of the silicate is reduced but a strong alkali metal salt is formed even at room temperature to obtain an inorganic heat-resistant corrosion-resistant coating composition that can be cured at room temperature there was.

In the present invention, a mixture of silicates of general formula (1) alone or in combination of two or more thereof is used by modifying one or two or more of the oxides and hydroxides of a metal selected from the metals or transition metals belonging to the group 1A of the periodic table. Another metal was added to the silicate aqueous solution so that the colloidal silicate was polymerized by the crosslinking reaction.

The modified silicates are prepared using oxides or hydroxides of metals such as aluminum oxide, aluminum hydroxide, sodium hexametaphosphate, calcium oxide, sodium hydroxide or potassium hydroxide as modifiers, the use of which is closely related to the molar ratio of silicates. There is a relationship. At this time, if the production using a lot of modifiers, the water resistance of the final coating is lowered and hardening at room temperature, so that the molar ratio (SiO ₂ / Na ₂ O) of the silicate can be increased indefinitely according to the content of the use. After all, the use of such a modifier is suitable for 0.1 to 10% by weight relative to the total content of the silicate. If the modifier is 0.1 wt% or less of the total content of the silicate, there is a limit in increasing the molar ratio of the silicate. If it is 10 wt% or more, the room temperature hardening is not only difficult but also the water resistance is lowered. Therefore, it is preferable to use it at 0.5 to 5 weight%.

Such modified silicates can be prepared by a known method of heating or hydrolyzing the above-mentioned modified first type or two or more types in one or two or more kinds of silicates of the general formula (1). The molar ratio of this modified silicate is 2.8-3.4. As such, by increasing the molar ratio of the modified silicate to completely disperse or dissolve the fine particulate silica compound, the molar ratio of the silicate can eventually be increased. Microparticulate silica used herein includes colloidal silica or soluble amorphous silica.

The molar ratio of silicate is increased by injecting a modified silicate solution while dissolving colloidal silica. In this case, as colloidal silica used, PH represents an alkali, and solid content of 20 to 50% may be used. As the content of the colloidal silica increases, the molar ratio of silicate increases, so that the film state of the adhesive becomes different. That is, if the molar ratio is 2.8 to 7.03, the film state is good, but if it is 7.03 or more, film formation is difficult. Therefore, it is preferable to adjust molar ratio to 3-6. The content of colloidal sol (based on 40% solids) is 5 to 60 parts by weight based on 100 parts by weight of the modified silicate.

The adhesive thus prepared is used in an amount of 10 to 50% by weight or less of the entire subject matter, and when it is used in an amount of 10% by weight or less, bubbles are generated in the coating film during formation of the final coating film. Will occur. Therefore, more preferable usage-amount is 15 to 35 weight%.

On the other hand, as another method of increasing the molar ratio, it is possible to increase the molar ratio of the silicate by dissolving amorphous silica in the modified silicate, this amorphous silica is prepared by the following method.

That is, ethyl obtained by hydrolyzing ethyl silicate (Si (OC ₂ H ₅ ) ₄ ), methyltrimethoxysilane, methyltriethoxysilane and the like with colloidal silica or colloidal alumina in a 1: 2 to 2: 1 equivalent ratio After drying methyl, methoxy silica gel at 100 ° C. for 1 hour to obtain soluble amorphous silica or silica compound, dissolving it in an aqueous silicate solution increases the molar ratio of silicates. At this time, as the amount of the amorphous silica is added, the molar ratio of the silicate increases and the viscosity of the silicate solution increases. The amount is preferably 1 to 40 parts by weight based on 100 parts by weight of silicate, and if the amount of the soluble amorphous silica or silica compound is 1 part by weight or more based on the entire silicate, the viscosity of the silicate is excessively increased, so 3 to 30 parts by weight. It is preferable to use. The molar ratio of the silicate at this time is 2.8-7.03.

In this way, the silicate with increased molar ratio, that is, an adhesive may be prepared using an extender pigment such as inorganic pigment, mica, talc, zeolite or wollastonite and distilled water or tap water (purified water). Same as

Distilled water is used in 5 ~ 30% by weight of the entire main body, when using less than 5% by weight of distilled water, the viscosity of the main is increased, making the coating impossible, and when used at 30% by weight or more, the rate of curing after coating is slow. . In addition, the pigment is preferably used in 10 to 50% by weight of the entire subject matter, if the pigment is used in less than 10% by weight of the paint is poor, if used in more than 50% by weight may adversely affect the corrosion resistance. . In addition, it is preferable to use the extender pigment at 20 to 80% by weight of the entire subject matter. If it is used at 20% by weight or less, cracks may occur during film formation due to a decrease in solid content. Adhesion falls. Therefore, it is preferable that it is 30-50 weight%. That is, the main material is prepared by mixing 10-50% by weight of adhesive, 5-30% by weight of distilled water, 10-50% by weight of pigment, 20-80% by weight of sieving pigment, and dispersing it with a ball mill or sand mill to save 200 mesh.

In the present invention, a curing agent may be a known one such as an oxide, hydroxide, or phosphate compound of a polyvalent metal, but such a curing agent has a problem that heat curing of 200 ° C. or higher is required to form an inorganic coating film through a polycondensation reaction with a silicate. have. Therefore, in the present invention, since the final coating composition is to be cured at room temperature, a curing agent is used using the following phosphate compound or complex salt. That is, ZnO, calcium oxide, strontium zinc phosphosilicate (0.3CaO.0.05SrO.0.65ZnO.0.15P ₂ O ₅ .0.3OSiO ₂ .0.4H ₂ O), magnesium oxide, ammonium phosphate, aluminum triphosphate, Aluminum polyphosphate, magnesium phosphate, calcium silicate, aluminum metapospace, barium sulfate or the like is mixed alone or in combination of two or more, and zinc dust or aluminum dust is mixed again to prepare a curing agent with distilled water.

In the present invention, one or two or more phosphate compounds or complex salts are mixed at the same weight ratio, and then mixed again with zinc dust or aluminum dust, whereby the hardening time of the coating film is shortened as the metal dust content is increased. Care must be taken in the use of these as they should consider their impact on the stability and color of the material. That is, the metal oxide and the composite salt are mixed 20 to 80% by weight of the total curing agent, the metal dust is 5 to 50% by weight of the total curing agent, and the amount of the metal oxide and the composite salt is used to 20% by weight or less of the total curing agent When the final coating film is formed, bubbles are severely generated in the coating film, and when it is 80% by weight or more, cracks are generated. In addition, if the amount of the metal dust used is 5% by weight or less of the entire curing agent, it is difficult to cure at room temperature, and when the amount of the metal dust is 50% by weight or more, the storage performance is poor, so it is preferably 0.7 to 30% by weight.

Distilled water or purified water is added to and dispersed in the mixed metal dust, phosphoric acid compound, or complex salt to prepare the curing agent of the present invention. In this case, the content of distilled water or purified water is preferably 20 to 60% by weight of the total curing agent. If it is 20 wt% or less, the viscosity is high and handling becomes very difficult. If it is 60 wt% or more, the curing time becomes very long due to excessive moisture.

The main body and hardener prepared in this way are mixed and sprayed prior to field work, or coated using a brush or roll, and then left at room temperature for 2 to 3 days (2 days in summer and 3 days in winter) to completely cure. Excellent heat and corrosion resistance and heat resistance will be expressed.

Hereinafter, the present invention will be described in detail through preferred embodiments.

Preparation Example of Amorphous Silica Unit: g

In Examples 1, 2, 3 and 4, ethyl, methylmethoxy, methylethoxysilica gel was prepared by hydrolyzing the raw materials a, b or c with d or f, and then dried in an oven at 100 ° C. for 20 minutes. Amorphous silica was prepared, and Comparative Examples 1 and 2 are compositions of amorphous silica compositions of Korean Patent Publication No. 91-6387.

Subject Manufacturing Example Unit: g

In Examples 5, 6, 7, 8 and 9, the raw materials were sequentially added, dispersed in a ball mill, and then saved at 250 # to prepare a subject of the present invention. Comparative Examples 3, 4, and 5 It is a composition of the subject matter disclosed in Korean Patent Publication No. 91-6387.

In Examples 10, 11, 12, 13, and 14, except distilled water was added to the raw materials in order and dispersed for 2 hours by a homomixer, and then the dispersed powder was re-injected into the prepared distilled water and pre-treated with a dissolver for 1 to 2 hours. After mixing to save 100 # to prepare a curing agent composition of the present invention, Comparative Examples 6 and 7 shows the curing agent composition of Korean Patent Publication No. 91-6387.

In Examples 15 to 20, the main body and the curing agent were mixed with the composition shown in the above table, followed by mixing for 20 minutes with a stirrer (300-500 rpm), and then using a sprayer for solvent-desorbed SPP (6 × 150 × 2 mm). After coating to 150㎛ thickness and left for 3 days at room temperature, the physical properties were examined, and in Comparative Examples 8, 9 and 10 were also mixed with the main agent and the curing agent in the composition shown in the table above and stirred for 30 minutes After coating the iron plate (6 × 150 × 2mm) with a spray film thickness of 30 μm, heat-hardening it at 250 ° C. for 30 minutes in an oven and performing physical property test. The progress is shown in the following table.

At this time, the adhesiveness was tested by cellophane tape after cutting the specimen diagonally into 5 × 5mm, and the boiling water test was observed by immersing the specimen in boiling water for 1 hour, and the heat resistance was maintained at 500 ° C. for 300 hours. After slow cooling over 60 days after the observation was made by visual observation. In addition, the thermal corrosion resistance was quenched three times at 500 ℃ for one hour, and then sprayed 5% saline and visual observation after 720 hours, 1440 hours (60 days) after spraying 5% saline to the specimen for corrosion resistance After visual observation, acid resistance was also immersed in 5% brine CH ₃ COOH for 1 hour at room temperature, alkali resistance was tested by immersing the specimen in 5% saline NaCl for 1 hour at room temperature.

Comparison of Physical Properties According to Examples and Comparative Examples

Claims (8)

10-50% by weight of the adhesive which increased the molar ratio (SiO ₂ / Na ₂ O) of silicate to 2.8-7.03 with silicate or modified silicate and soluble amorphous silica or colloidal silica, mica, talc, wollastonite Main body consisting of 20 to 80% by weight of extender pigments, 10 to 50% by weight of inorganic pigment, 5 to 30% by weight of distilled water or purified water; A room temperature-curable inorganic coating composition composed of a curing agent composed of 20 to 80% by weight of a phosphoric acid compound and a complex salt, 5 to 50% by weight of zinc dust or aluminum dust, and 20 to 60% by weight of distilled water. The room temperature-curable inorganic coating composition according to claim 1, wherein the soluble amorphous silica is dried after hydrolysis of ethyl silicate, methyltrimethoxysilane and methyltriethoxysilane with colloidal silica or colloidal alumina. The room temperature-curable inorganic coating composition according to claim 1, wherein the soluble amorphous silica is colloidal silica. The room temperature-curable inorganic coating composition according to claim 1, wherein the molar ratio (SiO ₂ / Na ₂ O) of the silicate is increased to 2.8 to 7.03 using soluble amorphous silica or colloidal silica. The room temperature-curable inorganic coating composition according to claim 1, wherein the modified silicate is modified by adding 1 to 10 parts by weight of a metal hydroxide or a metal salt to 100 parts by weight of the silicate. The room temperature-curable inorganic coating composition according to claim 1, wherein the curing agent is prepared from a phosphate compound or a complex salt composed of aluminum-based phosphate, strontium zinc phosphosilicate, calcium silicate, barium sulfate. The room temperature-curable inorganic coating composition according to claim 1, wherein the silicate is one or a mixture of two or more kinds of sodium silicate potassium silicate. 8. The coating composition according to claim 7, wherein the molar ratio of silicate is increased by dissolving soluble amorphous silica to 2.8 to 7.03.