KR19990050184A - Zinc-based inorganic paint with excellent corrosion protection and heat dissipation - Google Patents

Abstract

The present invention relates to a zinc-based inorganic paint excellent in anticorrosion and heat dissipation,

Spherical zinc powder: a pigment in which a plate-shaped aluminum flake (Al flake) surface-coated with an organic solvent for lowering surface wettability is mixed in a weight ratio of 1: 0.03-0.2,

Composed of inorganic silicate solvents and other necessary additives,

The mixing weight ratio of the pigment and the inorganic silicate solvent is 85: 15-95: 5,

The particle size of the zinc powder is 2-7 μm,

The particle size of the plate-shaped aluminum flakes is provided with a zinc-based inorganic paint having an average length of 20-30 x 5-10 x 0.5 탆 thick.

According to the present invention, the inorganic zinc-plate aluminum flake mixed paint exhibits long-term superior performance in generating white rust and red rust than conventional inorganic zinc paint, and the heat dissipation performance of the coating film is also up to 20 times higher. Can be extended and heat dissipation can be increased.

Description

Zinc-based inorganic paint with excellent corrosion protection and heat dissipation

The present invention relates to anti-corrosion and heat-dissipating zinc-based inorganic paints for steel materials used in steel structures, such as various chemical internal equipment, power facilities, and more particularly, by separating the spherical zinc particles and plate-shaped aluminum flake particles. It is related with this excellent zinc type inorganic coating.

Steel materials used in various steel structures such as industrial machinery, chemical facilities, electric power facilities, buildings, etc. widely adopt a paint coating method for applying paint on metal surfaces in order to improve surface protection and corrosion resistance. In recent years, the use of the inorganic zinc paint whose main components of the coating are zinc powder and inorganic silicate solvent is increasing.

Inorganic zinc paints generally consist of pigments and solvents, and pigments consist of zinc powder with an average diameter of 2-10 μm and other inorganic extender pigments. The solvent is an inorganic silicate as a conductor and some additives such as other water and dilute hydrochloric acid. Consists of The weight ratio is approximately 90% pigment and 10% solvent.

The conventional inorganic zinc paint protects the steel material from corrosion by two functions. First, the corrosion control of the steel material is controlled by the sacrificial anode method of the zinc powder contained in the paint. It is a protective action against the coating of corrosive factors. With these two anticorrosive actions, inorganic zinc paints are known to exhibit excellent conventional anticorrosive performance.

However, since the conventional inorganic zinc paint mainly exhibits anticorrosion by using the electrochemical sacrificial action of the zinc powder in the paint component, the zinc powder is anodized against the steel at the interface between the zinc powder and the steel material. This requires the establishment of an electrical circuit. Therefore, as the zinc powder is corroded by sacrificial action over time in a corrosive environment, the sacrificial corrosion performance of zinc decreases due to the consumption of zinc powder and the disconnection of electrical circuits between zinc powders due to the corrosion products of zinc. Can not protect for a long time.

In addition, in a very corrosive environment such as a chemical plant, zinc corrosion products generated by excessive sacrificial action of zinc powder cause volume expansion and escape from the inside of the inorganic zinc coating film, resulting in the destruction of the coating film. There is a disadvantage in that it does not act for a long time to prevent the penetration of corrosive factors such as.

In addition, when the organic coating is coated on top of the inorganic zinc coating, bubbles may be generated on the surface of the organic coating, which is a top coat. Therefore, Japanese Patent No. 61124506 maximized the sacrificial method by increasing the effective surface area of zinc by making the zinc particles into a plate shape, but this also causes white rust to occur on the surface, and in Korean Patent Application No. 93-12388 "High Weathering Antirust Coating" In order to improve the shortcomings of the conventional inorganic zinc paint, zinc powder is mixed with a relatively large aluminum powder having a particle size of 2-4 times that of zinc powder so that the corrosion product of zinc does not elute out of the coating film and damage the coating film for a long time. Inorganic zinc-aluminum powder-based paints have been proposed to prevent the formation of pores, but when spray coating, there is a high probability of porosity between large aluminum pigments and local red rust occurs when corrosive ions penetrate into this area.

Also, in corrosive environments, zinc corrosion products in the coatings accumulate, which breaks the electrical circuit between the zinc particles, preventing zinc from satisfactory sacrificial protection against steel. These conventional corrosion resistant paints have no or very poor heat dissipation.

Accordingly, in the domestic application 95-66216 "High weathering zinc-based anti-corrosion paint," as a means for imparting heat dissipation, zinc powder and plate-shaped aluminum powder are replaced by zinc powder, which is very low in white rust and red rust, and plate-shaped aluminum sheet. Although weathering method and heat-resistant inorganic zinc-plate aluminum-based paints having improved heat dissipation using sand properties have been disclosed, heat reflectivity is lowered due to disordered mixing of zinc particles and plate-shaped aluminum particles in the coating film, resulting in poor heat dissipation. There is this.

In addition, silver powder-based heat dissipating paints that are currently used are excellent in heat dissipation performance, but has a disadvantage in that they have to be frequently coated due to their short life under severe corrosion atmosphere. Therefore, a paint having both high corrosion resistance and heat dissipation is required.

Accordingly, an object of the present invention is to coat a plate-shaped aluminum flake with an organic solvent that lowers the surface wettability to separate the plate-shaped aluminum particles and the spherical zinc particles to provide a zinc-based inorganic paint having heat dissipation and corrosion resistance of the zinc powder. To provide.

1 is a cross-sectional view after applying the anticorrosive and heat dissipating zinc-based inorganic paint of the present invention.

* Description of the symbols for the main parts of the drawings *

1.Plate shaped aluminum flake particles

2 ... spherical zinc particles 3 ... silicate solvent

4 ... steel sheet

According to the invention,

Spherical zinc powder: a pigment in which a plate-shaped aluminum flake (Al flake) surface-coated with an organic solvent for lowering surface wettability is mixed in a weight ratio of 1: 0.03-0.2,

Composed of inorganic silicate solvents and other necessary additives,

The mixing weight ratio of the pigment and the inorganic silicate solvent is 85: 15-95: 5,

The particle size of the zinc powder is 2-7 μm,

The particle size of the plate-shaped aluminum flakes is provided with an average length of 20-30 × 5-10 × thickness 0.5㎛ thickness and a zinc-based inorganic paint excellent in heat dissipation.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention replaces zinc powder, which is a pigment component constituting the inorganic zinc paint, with a mixed powder of zinc powder and a plate-shaped aluminum flake coated with an organic solvent that reduces surface wettability, so that aluminum flake particles in the coating film float on the coating film during coating. Therefore, the reflectivity is increased and the spherical zinc powder has the same corrosion resistance as the existing zinc paint at the bottom.

Inorganic zinc paints are largely composed of pigments and solvents, of which dual pigments contain zinc powder, plate-shaped aluminum flakes and extender pigments.

In this case, the extender pigment is not necessarily contained, and an inorganic silicate is used as the solvent, and an additive may be added.

The size of the zinc powder is preferably about 2-7㎛. Plate aluminum flake (Al flake) refers to plate aluminum powder that is commercially available in the form of aluminum paste (Al paste) in the form of scale pieces smaller than 30 μm. 35% solvent is mixed.

In the present invention, aluminum flakes are surface-coated using stearic acid which reduces the surface wettability of aluminum flakes as the organic solvent.

If the average size of the plate-shaped aluminum particles (powder) is large or long, the coating effect is reduced, it is preferable that the average length of 20-30㎛, width 5-10㎛ and thickness of about 0.5㎛, average length 30㎛, width 5 micrometers and the thickness of 0.5 micrometer are more preferable.

When the content of the plate-shaped aluminum flakes in the pigment is increased, the heat reflectivity is improved, but the plate-shaped aluminum powder is concentrated only on the upper portion of the coating, resulting in a relatively solvent-reducing effect, resulting in a poor coating film strength and thus a large film peelability. On the contrary, when the amount of the plate-shaped aluminum flake powder is too small, there is no heat reflecting effect, so when the zinc powder is set to 1, the mixing weight ratio of each powder in the pigment is preferably 1: 0.03-0.2 of spherical zinc powder: plate-shaped aluminum powder.

The extender pigment which can be added to the pigment has the effect of reinforcing and swelling the coating film and preventing the flow of the paint during coating, and the amount thereof is usually 10 wt% or less based on the weight of the paint, preferably 5 -10% by weight. The above effect is not achieved when the amount of the extender pigment is added, and the anticorrosive performance may be reduced when it is added in excess. Examples of the extender pigment include aluminum oxide, calcium carbonate and silica (Si), and these may be added alone or in combination.

In general, when the amount of solvent is too large when the paint is dried, the amount of pigment per unit volume is relatively low, so sacrificial protection and sealing are inferior. When the amount of solvent is too small, pores in the film may be high, causing moisture, oxygen, and other corrosive ions. The anticorrosive performance is reduced because it easily penetrates into the coating film and the strength of the coating film is weakened and the coating film is brittle. Therefore, it is preferable that the mixing weight ratio of a pigment and a solvent is 85: 15-95: 5, and, as for a normal dry coating film, a weight ratio 90:10 is more preferable.

The solvent for dissolving the pigment serves to form a coating film with an inorganic silicate, and is preferably used in a liquid phase so as to be easily mixed with the pigment.

As another additive, a hydrochloric acid solution which acts as an acid catalyzer to promote drying of the coating film may be added in an amount of 0.2-0.4% by weight based on the total weight of the paint.

The hydrochloric acid solution reacts with zinc in the pigment to cause the coating film to harden. However, when the amount added is too large, the hydrochloric acid solution becomes gel and the coating workability deteriorates.

EMBODIMENT OF THE INVENTION Hereinafter, the system and the heat dissipation principle of the zinc-type inorganic antirust coating of this invention are demonstrated.

1 is an inorganic silicate solvent (3) using a mixed powder obtained by mixing a spherical zinc powder and a plate-shaped aluminum flake with a zinc powder of 1, such that the zinc: plate-shaped aluminum flake mixture weight ratio is 1: 0.03-0.2. It is sectional drawing of the inorganic zinc-plate type aluminum flake-type paint manufactured by the above.

The plate-shaped aluminum powder on the steel sheet 4 is present in the upper part of the coating film and the zinc particles are evenly arranged in the lower part of the coating film so that the plate-shaped aluminum powder on the upper part of the coating film forms a highly effective heat reflection layer, and the zinc particles in the lower part of the coating film are sacrificed. It can be seen that it protects the steel, which is the workpiece. In addition, the inorganic silicate solvent 3 forms the whole coating film.

EMBODIMENT OF THE INVENTION Hereinafter, the Example of this invention is described.

Example

To the composition as shown in Table 1 was prepared an existing inorganic zinc paint (comparative example) and the paint of the present invention (Example 1-3).

Type of paint Comparative example Example 1 Example 2 Example 3 Content ratio (%) Content ratio (%) ratio Content ratio (%) ratio Content ratio (%) ratio Content for Pigments * Zinc powder 86 85 One 84 One 77 One Aluminum Plate Flakes Powder - 4 0.05 9 0.11 15 0.2 Sieving pigment 14 11 7 8 Pigment: Solvent content ratio in dry coatings ^* Pigment 91.7 90.4 90.2 90.2 menstruum 8.3 9.6 9.8 9.8

*weight%

The paint was coated on a steel plate to a thickness of 60 μm to prepare a specimen, and then a salt spray test was performed. The results are shown in Table 2 below.

Comparative example Example 1 Example 2 Example 3 White rust occurrence time (hr) 24 200 600 1000 Red rust occurrence time (hr) 1200 1500 1400 1300

As shown in Table 2, the inorganic zinc-plate aluminum flake mixed paint of the present invention (Examples 1-3) shows superior performance for a very long time in the generation of white rust and red rust than conventional inorganic zinc (comparative example), As a result, the corrosion protection period of various steel structures can be extended.

Furthermore, in order to measure the heat reflectivity of the present invention, the light reflectance, which is known to be proportional to the heat reflectivity, was tested and the results are shown in Table 2 below.

Comparative example Example 1 Example 2 Example 3 Light reflectivity (glossiness, GU) 0.9-1.0 3-4 10-12 15-20

As shown in Table 3, it can be seen that the aluminum flake layer forms a heat reflection layer and exhibits excellent light reflectivity (heat dissipation) by 3-20 times or more than the conventional inorganic zinc paint.

As described above, the inorganic zinc-plate aluminum flake mixed paint exhibits long-term superior performance in generating white rust and red rust than conventional inorganic zinc paint, and the heat dissipation performance of the coating film is also up to 20 times higher, resulting in the corrosion protection period of various steel structures. Can be extended and heat dissipation can be increased.

Claims (3)

Spherical zinc powder: a pigment in which a plate-shaped aluminum flake (Al flake) surface-coated with an organic solvent for lowering surface wettability is mixed in a weight ratio of 1: 0.03-0.2, Composed of inorganic silicate solvents and other necessary additives, The mixing weight ratio of the pigment and the inorganic silicate solvent is 85: 15-95: 5, The particle size of the zinc powder is 2-7 μm, The particle size of the plate-shaped aluminum flakes is an average length of 20-30 × 5-10 × 0.5 탆 thick and zinc-based inorganic paint with excellent heat dissipation The coating material according to claim 1, wherein the organic solvent for surface coating the plate-shaped aluminum flake is stearic acid. The method of claim 1, wherein the additive is one or more extender pigments selected from aluminum oxide, calcium carbonate and silica is added to 10% by weight or less based on the total weight of the paint, A paint characterized by adding 0.2-0.4% by weight of hydrochloric acid as an acid catalyst based on the total weight of the paint.