KR20090007877A - A composition for coating steel materials containing carbon nanotube and a manufacturing method therefor - Google Patents

Abstract

A steel sheet coating composition containing carbon nanotube is provided to ensure excellent chemical resistance, abrasion resistance, heat resistance, and fire retardancy without containing a chrome as a harmful component. A steel sheet coating composition containing an inorganic etchant comprises aqueous resin composition containing aqueous resin and water, water dispersible silica as an inorganic anticorrosive additive and carbon nanotube.

Description

A composition for coating steel materials containing carbon nanotube and a manufacturing method therefor}

Due to the development of the electronics industry and related production technologies, home appliances are becoming more advanced and more durable.

On the other hand, in order to increase the durability of home appliances, it is necessary to increase the durability of the steel sheet forming the appearance of the product.

The galvanized steel sheet as the steel sheet durability increasing means as described above has been gradually converted into an electrogalvanized steel sheet from the initial cold rolled steel sheet.

However, in the case of electro-galvanized steel sheet, the corrosion resistance is greatly improved, but not only the surface aesthetics are damaged due to contact with the operator's hand, but also recently, the steel sheet of various characteristics has reached the limit which is difficult to handle.

In such a situation, an anti-fingerprint steel sheet, a lubricated steel sheet or an organic coated steel sheet for automobiles has been developed in which a thin film of resin is coated on the surface of a steel sheet instead of zinc.

In the case of anti-fingerprint steel sheet, it has the characteristics of long-lasting appearance and good printability as it has resistance to human fingerprints, that is, fingerprint. In the case of lubricated steel sheet, forming work using steel sheet (sheet metal press In the case of work), there is a feature that greatly improves the workability.

The coated lubricating steel sheet can be coated with a resin for processing oil to obtain the effect of improving workability as well as improving working environment, corrosion resistance and fingerprint resistance.

In addition, it is possible to produce a steel sheet having a higher corrosion resistance through a chromate-treated resin coating that is particularly excellent in corrosion resistance.

However, in the case of chromate-treated resin coating, since hexavalent chromium contained in the chromium film on the surface of the steel sheet is easy to vaporize and has strong oxidizing property and high toxicity, difficulty in breathing in contact with the human body, nasal mucosal inflammation, dysplasia of kidney, bronchial cancer , Lung cancer and the like.

In addition, the volatile hexavalent chromium is reduced to a stable but stable trivalent chromium even after exhibiting strong oxidative toxicity by the human body, causing another problem.

In consideration of this point, and in response to recent environmental regulations, the necessity of developing a chromium-free resin coating liquid for steel sheets of a preferred form or structure is increasing.

The present invention relates to a steel sheet coating liquid composition and a method for manufacturing the same, and more particularly, by dispersing and containing the carbon nanotubes, which have been introduced into tablets and functional groups, in water-soluble resins in the form of emulsions or solutions, excellent chemical resistance, abrasion resistance, heat resistance, The present invention relates to a carbon nanotube-containing steel sheet coating liquid composition as a nanonized hybrid composition of a water-soluble resin having flame retardancy and fouling resistance, and a method for producing the same.

The present invention relates to a steel sheet coating liquid composition and a method for manufacturing the same, and more particularly, by dispersing and containing the carbon nanotubes, which have been introduced into tablets and functional groups, in water-soluble resins in the form of emulsions or solutions, excellent chemical resistance, abrasion resistance, heat resistance, The present invention relates to a carbon nanotube-containing steel sheet coating liquid composition as a nanonized hybrid composition of a water-soluble resin having flame retardancy and fouling resistance, and a method for producing the same.

The present invention has been made in view of the above problems, and provides a steel sheet coating liquid composition and a method for producing the coated steel sheet, which are excellent in corrosion resistance than a conventional chromium-containing coating liquid composition, and which can produce a coated steel sheet at a lower price than a galvanized steel sheet. There is a purpose.

It is still another object of the present invention to provide a non-chromium-based steel sheet coating liquid composition having excellent corrosion resistance without containing chromium as a harmful component as in the prior art and a method of manufacturing the same.

As described above, according to the steel sheet coating liquid composition of the present invention, while excellent in corrosion resistance than when using a conventional chromium-containing coating liquid composition, it is possible to produce a steel sheet at a lower price than a galvanized steel sheet.

As mentioned above, since it does not contain chromium as a harmful component in addition to the effect of reducing manufacturing costs, the value or meaning of the present invention is very great in terms of environment-friendliness and corrosion resistance.

The carbon nanotube-containing steel sheet coating liquid composition according to the present invention for achieving the above object comprises an aqueous resin composition containing an aqueous resin and water, and colloidal silica, carbon nanotubes and other additives as corrosion resistance additives. .

Here, when describing the carbon nanotubes as one of the essential components in the coating liquid composition of the present invention, the carbon nanotubes, the nano-sized graphite surface has a round shape in a cylindrical structure and has a unique physical shape depending on the size or shape As a macromolecular molecule having properties, tensile strength is 8 times that of steel and thermal conductivity is 5 times that of copper, but due to structural characteristics in a fine powder state, it is difficult to express electrical and mechanical properties by itself.

Therefore, there is a limit in the bonding strength with the polymer resin, so a pull-out phenomenon occurs in which carbon nanotubes are released when a crack occurs. The surface of the carbon nanotubes is modified to improve dispersibility and interfacial adhesion with the polymer matrix. This solved this problem.

Preferably, 60 to 80% by weight of the aqueous resin composition, 1 to 20% by weight of colloidal silica as a corrosion resistant additive, 0.5 to 10% by weight of carbon nanotubes, 0.5 to 10% by weight of other additives such as lubricants and adhesion promoters required for coating Include.

Steel sheet coating liquid composition of the present invention having a component ratio as described above is preferably to have a glass transition temperature of 20 to 90 ℃, molecular weight of 50,000 to 300,000 range.

As used herein, an aqueous resin is meant to include not only the original water-soluble resin, but also a water-insoluble resin in the form of an emulsion or suspension in which the resin is finely dispersed in water.

Aqueous resins of the above meanings include, for example, polyolefin resins, polyurethane resins, acrylic resins, polycarbonate resins, epoxy resins, polyester resins, alkyd resins, phenol resins and other thermosetting resins, preferably crosslinking It is a binder resin.

More preferable aqueous resins include acrylic resins, polyurethane resins, and mixtures thereof, and two or more kinds of resins may be mixed and used as such.

The carbon nanotube-containing corrosion inhibitor of the present invention forms an adhesive corrosion resistant film, that is, a resist on the surface of the steel sheet, and as a result, the penetration of corrosive liquids is blocked, and the surface of the steel sheet becomes inert due to the formation of corrosion resistant ions.

As the resist is formed, of course, the water resistance, acid resistance and alkali resistance of the steel sheet are improved.

In the present invention, the carbon nanotube as the corrosion inhibitor, like conventional chromate, tends to easily adhere to the metal surface and has excellent oxidation ability to inactivate the metal surface.

Hereinafter, the steel sheet coating liquid composition of the present invention will be described in detail based on Examples and Comparative Examples.

However, these examples and comparative examples are only examples for explanation, and of course, do not limit the technical scope of the present invention.

The coating object to which the steel sheet coating liquid composition of the present invention is applied is a galvanized steel sheet or an unplated steel sheet.

First, in preparing specimens for various tests on the steel sheet coating liquid composition of the embodiment of the present invention, the coating liquid composition of each embodiment was coated on the electrogalvanized steel sheet with a bar coat # 4 by 1 μm thickness, and then It was set as the method of drying under 160 degreeC temperature.

Example 1

The total resin concentration of the acrylic resin and the polyurethane resin is 15% by weight, mixed with pure water at a ratio of 1: 1 (weight ratio of solids), 50 g / l colloidal silica, 5 g / l carbon nanotube, Then, 50 g / L of other additives were added, and then the mixture was dispersed with a disperser for 30 minutes and the pH value was adjusted to 8.0 to prepare a steel plate coating liquid composition of the example.

Example 2

The total resin concentration of the acrylic resin and the polyurethane resin is 15% by weight, mixed with pure water at a ratio of 1: 1 (weight ratio of solids), 50 g / l of colloidal silica and 10 g / l of carbon nanotubes. And 50 g / L of other additives were added, and then the mixture was dispersed with a disperser for 30 minutes and the pH value was adjusted to 8.0 to prepare a steel plate coating liquid composition.

Example 3

The amount of carbon nanotube mixture was increased to 30 g / L to prepare a steel sheet coating liquid composition of the example in the same manner as in Example 1.

Comparative Example 1

The total resin concentration of the acrylic resin and the polyurethane resin is 15% by weight, mixed with pure water at a ratio of 1: 1 (weight ratio of solids), and 50 g / l of colloidal silica and 50 g / l of other additives are added. Next, a steel plate coating liquid composition of Comparative Example was prepared in the same manner as in Example 1.

Comparative Example 2

The total resin concentration of the acrylic resin and the polyurethane resin is 15% by weight, mixed with pure water at a ratio of 1: 1 (weight ratio of solids), 50 g / l colloidal silica, 50 g / l other additives, and After adding 5% by weight of strontium chromium, a steel plate coating liquid composition of Comparative Example was prepared in the same manner as in Example 1.

Each component ratio constituting the steel sheet coating liquid of the Examples and Comparative Examples is as shown in Table 1 below.

[Table 1] Component ratio comparison table (unit: g)

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Polyurethane resin 350 350 350 350 350 Water soluble acrylic resin 350 350 350 350 350 Other additives 50 50 50 50 50 Water Dispersible Silica 50 50 50 50 50 Carbon nanotubes 5 10 30 - - Strontium Chromate - - - - 5.0

Each specimen coated with the steel plate coating liquids of these Examples and Comparative Examples was dried at 160 ° C. for 1.5 minutes and then tested for simple film properties.

[Table 2] Coating characteristics comparison table (A)

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2         5% NaOH  4 minutes peeled off  28 minutes peeling start  29 minutes peeling off  2 minutes peeling off  8 minutes peeling start         5% HCl 2 minutes peeling start 5 minutes complete peeling 28 minutes peeling start 35 minutes peeling off 2 minutes start peeling 5 minutes 8 minutes start peeling 10 minutes

According to the above [Table 2], it can be seen that the coating stability is remarkably excellent in the case of the specimen coated with the coating solution of the present invention.

In addition, coating stability starts to increase rapidly between 0.5% and 1%, and it can be seen that there is no significant difference between 1% and 3%.

Claims (5)

An inorganic corrosion resistant agent-containing steel sheet coating liquid composition comprising an aqueous resin composition containing an aqueous resin and water, and water-dispersible silica and carbon nanotubes as inorganic corrosion resistant additives. The method of claim 1, The steel sheet coating liquid composition is 60 to 80% by weight of the aqueous resin composition, 1 to 20% by weight of colloidal silica as a corrosion resistance additive, 0.5 to 10% by weight of carbon nanotubes, 0.5 to 10% by weight of other additives such as lubricants, adhesion promoters, etc. Inorganic anticorrosive-containing steel sheet coating liquid composition comprising a. The method according to claim 1 or 2, The aqueous resin composition is an inorganic corrosion-resistant steel sheet coating liquid, characterized in that selected from the group consisting of polyolefin resin, polyurethane resin, acrylic resin, polycarbonate resin, epoxy resin, polyester resin, alkyd resin, phenol resin and thermosetting resin Composition. The method according to claim 1 or 2, The steel sheet coating liquid composition is an inorganic corrosion-resistant steel sheet coating liquid composition, characterized in that the glass transition temperature of 20 to 90 ℃, molecular weight 50,000 to 300,000. Mixing 60 to 80% by weight of the aqueous resin composition, 1 to 20% by weight of colloidal silica as a corrosion resistant additive, 0.5 to 10% by weight of carbon nanotubes, 0.5 to 10% by weight of other additives such as lubricants required for coating and adhesion promoter, and And dispersing these mixtures with a disperser for 30 minutes, and adjusting the pH value of the dispersion mixture to 8.0.