KR20190044205A - Coating kit, multi-layered film using the same, and method of forming the same - Google Patents

Abstract

The present invention relates to a paint kit capable of improving coating film properties, a multi-layered coating film using the same, and a method for forming the same. The paint kit of the present invention comprises: an aqueous epoxy-based paint composition including an epoxy resin, an acryl emulsion, an amide curing agent, a first pigment, and water; and an aqueous acrylic paint composition including an organic/inorganic composite copolymer emulsion, an elastic acrylic emulsion, a second pigment, and water.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating material, a coating material,

The present invention relates to a paint kit, a multilayer coating film using the same, and a method for forming the same.

Generally, an epoxy-based zinc-based, epoxy-based, and acrylic-based coating composition is widely used for container painting. As for the main purpose of each paint, the main purpose of the epoxy zinc plating is to protect the substrate and to prevent corrosion. In the case of the epoxy based coating, adhesion between the coating and the top coating is required, do. Finally, in the case of an acrylic top coat painted, appearance and weatherability are the main objectives.

For this purpose, oil-based coating compositions have conventionally been used as undercoat, middle and topcoat compositions. In recent years, however, as interest in the environment and energy has increased worldwide, there has been an increasing tendency to limit the use of organic solvents (or volatile organic compounds) derived from fossil raw materials. In many countries including Korea, Are being prepared or implemented.

Accordingly, it is necessary to develop a variety of environmentally friendly water-soluble paints that exceed the properties of conventional oil-based coating compositions.

Korea Patent Publication No. 2016-0077983

The present invention provides a paint kit.

The present invention also provides a multilayer coating film comprising the above coating kit.

In addition, the present invention provides a method of forming the multilayer coating film.

The present invention includes an epoxy resin having two or more epoxy groups, an aqueous emulsion coating composition comprising an acrylic emulsion, an amide curing agent, a first pigment and water, and an organic-inorganic hybrid emulsion, an elastic acrylic emulsion, a second pigment and water And a water-based acrylic paint composition.

The present invention also provides a multi-layer coating film comprising an aqueous epoxy coating layer on a substrate and an aqueous acrylic coating layer on the aqueous epoxy coating layer, wherein the epoxy coating layer comprises an epoxy resin having two or more epoxy groups, Wherein the water-based acrylic paint layer comprises an organic-inorganic hybrid emulsion copolymer, an elastic acrylic emulsion, a second pigment, and water, wherein the water-based acrylic paint layer is a layer formed by coating an aqueous epoxy composition coating composition containing an acrylic emulsion, an amide curing agent, Wherein the water-based acrylic coating composition is a layer formed by coating.

The present invention also relates to a method for forming an aqueous epoxy coating layer by coating and drying an aqueous epoxy composition coating composition comprising an epoxy resin, an acrylic emulsion, an amide curing agent, a first pigment and water having two or more epoxy groups on a substrate And a water-based acrylic coating composition comprising an organic-inorganic hybrid emulsion, an elastic acrylic emulsion, a second pigment and water on the aqueous epoxy coating layer to form an aqueous acrylic coating layer Lt; / RTI >

The paint kits of the present invention can achieve properties equivalent or superior to those of the oil based paints used in existing multilayer coatings by including aqueous epoxy coating compositions and aqueous acrylic coating compositions having specific component combinations. Further, an environmentally friendly multi-layer coating film can be formed, and the multi-layer coating film formed thereby can exhibit excellent appearance and paint workability, and improve physical properties such as adhesion, rust prevention and weather resistance.

Hereinafter, the present invention will be described in detail in order to facilitate understanding of the present invention.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

The coating material kit of the present invention comprises an epoxy resin having two or more epoxy groups, an aqueous emulsion coating composition containing an acrylic emulsion, an amide curing agent, a first pigment and water, and an inorganic or organic copolymer emulsion, an elastic acrylic emulsion, And an aqueous acrylic coating composition containing water.

The coating material kit of the present invention includes an aqueous acrylic coating composition containing an elastic acrylic emulsion and an aqueous epoxy coating composition having a specific component combination, thereby making it possible to use water-soluble paints and to provide a coating composition having excellent rust- And it is possible to form a multilayer coating film which is environmentally friendly and has an excellent appearance.

Hereinafter, the present invention will be described in more detail.

The coating kit of the present invention is an environmentally friendly coating kit comprising an aqueous epoxy coating composition and an aqueous acrylic coating composition.

The aqueous epoxy coating composition of the present invention comprises an epoxy resin having two or more epoxy groups, an acrylic emulsion, an amide curing agent, a first pigment and water.

The epoxy-based coating composition may contain an epoxy resin having two or more epoxy groups in order to ensure excellent adhesion and rust-proofing property. Examples of the epoxy resin include phenol novolak type epoxy resin, cresol novolak type epoxy resin, trishydroxyphenyl methane type epoxy resin, dicyclopentadiene phenol type epoxy resin, bisphenol-A type epoxy resin, bisphenol-F type epoxy resin, A biphenol-A novolak type epoxy resin, a naphthalene skeleton-containing epoxy resin, a glyoxylated epoxy resin, a heterocyclic epoxy resin, and the like can be used, but the present invention is not limited thereto. At this time, the content of the epoxy resin having two or more epoxy groups may play an important role in determining the physical properties of the coating film, and may be 20 to 40 parts by weight or 30 to 35 parts by weight. If the content of the epoxy resin having two or more epoxy groups is less than 20 parts by weight, water resistance and impact resistance may be lowered, and if it exceeds 40 parts by weight, adherence, corrosion resistance and chemical resistance may be lowered.

The epoxy resin having two or more epoxy groups may have an epoxy equivalent of 950 to 1050 g / eq and a solid content of 50 to 60% by weight. Exceeding this equivalent range may affect the crosslinking density and adversely affect the physical properties of the coating film such as the rust-inhibiting property or the adhesion property of the paint finally. In order to secure mechanical properties such as crack resistance and impact resistance, the epoxy resin may be a flexible resin having a softening point of -5 to 0 占 폚, but is not limited thereto.

In addition, the aqueous epoxy coating composition may contain an acrylic emulsion as an auxiliary resin in order to ensure impact resistance.

The acrylic emulsion may be contained in an amount of 3 to 10 parts by weight, or 3 to 9 parts by weight, and when the above range is satisfied, an excellent impact resistance can be realized. The acrylic emulsion may have a glass transition temperature (Tg) of -20 to 20 占 폚, a weight average molecular weight of 150,000 to 300,000 g / mol, an average particle size of 100 to 300 nm, a pH of 7 to 10, May be 40 to 60% by weight. If the glass transition temperature of the acrylic emulsion is less than -20 占 폚, the strength of the coating film may be lowered and the coating film may become too soft and adherence may be deteriorated. If the glass transition temperature exceeds 20 占 폚, the strength of the coating film becomes too hard The impact resistance may be lowered. If the pH is less than 7, gelation may proceed during storage of the coating, and if the pH is more than 10, the stability of the acrylic emulsion particles may decrease and the adhesion may deteriorate.

In the aqueous epoxy coating composition, the mixing ratio of the epoxy resin: acrylic emulsion having two or more epoxy groups may be 1: 0.1 to 1: 0.35 by weight. When the mixing ratio is satisfied, the physical properties of the coating film such as adhesiveness, impact resistance and weather resistance can be further improved without deteriorating corrosion resistance.

In addition, the aqueous epoxy coating composition may contain an amide curing agent to ensure adhesion, low-temperature drying, flexibility and rust resistance.

The amide curing agent includes an amine in the form of a polyamide and an alicyclic amine hydrogenated to aniline or an aromatic amine to which methylene is bonded, for example, a polyamide and a methylene-bridged poly (cyclohexyl-aromatic) amine (MPCA), [5,2,1,0] -tricyclodecane-2,6-bis-hexamethylene diamine, and methylene dianiline (MDA) have. The amide curing agent may have an activated hydrogen equivalent of 70-80 g / eq, a solid content of 35-45 wt%, and an amine value of 300-500 mg KOH / g. When the activated hydrogen equivalent of the amide curing agent is less than the above range, the water resistance and the rustproofing property may be deteriorated. If the amount is larger than the above range, the viscosity of the amide curing agent may be too high and spray workability may be deteriorated.

In the present invention, the amide curing agent may be contained in an amount of 1 to 5 parts by weight in the coating composition

In addition, the aqueous epoxy coating composition may include a first pigment to improve the hue of the coating composition and the mechanical properties of the coating composition.

The first pigment may be an extender pigment, an anticorrosive pigment and a colored pigment, and one kind thereof may be used alone, or two or more kinds of pigments may be used in combination.

First, the extender pigment may be selected from, for example, calcium carbonate, silica, dolomite, talc, barium sulfate, kaolin, mica, wollastonite, chlorite, aluminum silicate and aluminum hydroxide which are commonly used in water- have. These can be used alone or in combination for the purpose of manifesting the hardness and physical properties of the coating film. The extender pigment may be contained in an amount of, for example, 15 to 30 parts by weight, and may include, but is not limited to, barum sulfate and talc.

Examples of the colored pigment include, but are not limited to, titanium oxide, carbon black, phthalocyanine, and iron oxide, which are commonly used in water-soluble paints. These can be used alone or in combination for color reproduction of the coating film. The colored pigment may be contained in an amount of, for example, 10 to 15 parts by weight, and titanium oxide may be contained in an amount within the above range.

The rustproof pigments may also be used for improving corrosion resistance and include, for example, those selected from the group consisting of zinc aluminum phosphate, zinc phosphate, aluminum triphosphate, phosphosilicate and calcium modified silica, and combinations thereof . The rust-preventive pigment may be contained in an amount of, for example, 3 to 7 parts by weight.

The total content of the first pigment contained in the aqueous epoxy coating composition may be 28 to 55 parts by weight or 35 to 45 parts by weight. If the content of the first pigment is less than 28 parts by weight, the coating may have a low hiding power. If it exceeds 55 parts by weight, the interlayer adhesion between the coating films and gloss and color sharpness may be deteriorated, As well as the cause of the price increase of the paint.

Further, the aqueous epoxy coating composition contains water as a main solvent. Water acts as a dispersant for each particle in the paint or as a solvent for various compounds. When water is added to the paint, it is also used as a diluent. In the present invention, 5 to 20 parts by weight of water may be contained in the coating composition. The water used as a main agent is a very important factor for the paint of the present invention to have environmentally friendly properties. In the present invention, water can be used, for example, pure water or deionized water.

Further, the aqueous epoxy composition may further contain a solvent in addition to water. In the present invention, when the coating film is formed, the solvent helps the binder to fuse, making the coating more dense, and improving the wetting efficiency with respect to the substrate, thereby improving the adhesion.

In the present invention, 0.5 to 2.5 parts by weight of the solvent may be contained. When the amount of the solvent is less than 0.5 parts by weight, the film formation may be poor at a low temperature, and when the amount is more than 2.5 parts by weight, the drying speed may be very slow.

As the solvent in the present invention, for example, isopropyl alcohol, ethyl ether or a mixture thereof may be used.

In addition, the aqueous epoxy coating composition may contain various additives used in conventional coating compositions according to purposes, in addition to the above components.

The additives usable in the present invention may include, for example, at least one additive such as a dispersing agent, a surface modifier, a thickener, a defoaming agent, a humectant, a neutralizing agent, a surfactant and a thixotropic agent. In addition, the amount thereof to be used may also be added in an ordinarily applied amount.

DISPERBYK-160, DISPERBYK-180, DISPERBYK-190 and DISPERBYK-199 of BYK Co., Ltd., TEGO 752, TEGO 755 and TEGO 760 of EVONIK Co. can be used alone or in combination as the additive used for dispersing the pigment But it is not limited thereto, and ion type and non-ion type can be selected and used.

The dispersing agent may be contained in an amount of 0.1 to 2 parts by weight. If the content of the dispersing agent is less than 0.1 parts by weight, the dispersing efficiency of the pigment is greatly lowered, causing re-agglomeration of the pigment, which may cause cretering on the coating film, poor resistance to abrasion of the film, . If the content of the dispersant is more than 2 parts by weight, the transparency is excessively increased, which may cause deterioration of the hiding power of the coating film and increase of the cost, as well as the water resistance of the coating film due to the increase of the ionic group in the coating.

The surface modifier may include at least one additive selected from the group consisting of BYK-345, BYK-346, BYK-348 and BYK-349 of BYK, which is added for improving the smoothness of the coating material. Silicone, silicon, or other polymer type materials can be used to adjust the surface tension to improve the wettability to the substrate. The surface modifier may be included in an amount of 0.1 to 2 parts by weight.

The thickener is added to improve the flowability of the coating material and includes at least one selected from the group consisting of, for example, RW-8W of DOW, AQ-607, AQH-800 and AQ633E of KUSUMOTO, and Natrosol of Hercules . The thickener may be included in an amount of 0.1 to 0.9 parts by weight.

In addition, the antifoaming agent can suppress the occurrence of bubbles in the composition and suppress the pinhole phenomenon that occurs during drying of the coating film. The antifoaming agent may be added in the entire amount when preparing the paint, but a part of the antifoaming agent may be applied first in the pigment aqueous dispersion manufacturing process in order to remove bubbles generated in the production of the pigment water dispersion. Examples of commercially available products include DF-110D, Surfynol 104 from Airproduct, SN-DEFOAMER 1320 from San Nopco, BYK-024 and BYK-028 from BYK, and the like. The content of the antifoaming agent may be 0.1 to 1.9 parts by weight. If the content of the defoaming agent is less than 0.1 parts by weight, the ability to inhibit bubbles in the coating composition may be deteriorated. If the content exceeds 1.9 parts by weight, the water resistance may be deteriorated.

The wetting agent may be used for improving the wettability. For example, a polyether-modified siloxane (BYK349, BYK) may be used. The wetting agent may be included in an amount of 0.1 to 0.9 parts by weight. If the content of the wetting agent is out of the above range, the adhesion property of the coating film may be deteriorated.

The neutralizing agent may be at least one selected from the group consisting of formic acid, acetic acid, glacial acetic acid, lactic acid, and aromatic sulfonic acid. The neutralizing agent may be contained in an amount of 0.01 to 0.99 part by weight.

Surfynol 104 from Airprocut Co., Ltd., which does not contain an alkyl phenol ethoxylate (APEO) material, can be used as the surfactant, and Natrosol from Hercules Co., Ltd. as a thixotropic agent.

The aqueous epoxy coating composition comprises 20 to 40 parts by weight of an epoxy resin having two or more epoxy groups, 3 to 10 parts by weight of an acrylic emulsion, 1 to 5 parts by weight of an amide curing agent, 28 to 55 parts by weight of a first pigment, And if it satisfies the above range, it can be used as an intermediate coating composition. In this case, it can exhibit excellent adhesion as a bridge between the undercoat and the topcoat, and can improve the physical properties of the coating film as well as the anti- .

On the other hand, the coating material kit of the present invention includes an aqueous acrylic coating composition for achieving excellent appearance and weatherability, and it can be adhered to the aqueous epoxy coating composition.

The aqueous acrylic coating composition includes an organic-inorganic hybrid copolymer emulsion, an elastic acrylic emulsion, a second pigment, and water.

The organic / inorganic hybrid emulsion of the present invention may be a water-based emulsion resin comprising an acrylic monomer and a monomer containing an alkoxysilyl group or an epoxy silyl group, and may be synthesized to be capable of siloxane crosslinking in an acrylic main chain. The silyl group in the main chain reacts with moisture during the emulsion polymerization to be hydrolyzed to form a silanol, and then the silanol may be condensed to be crosslinked with a stable siloxane bond. Such crosslinking can proceed at room temperature, and the bonding force of the siloxane bond is about 443 KJ / mol, which shows excellent weather resistance comparable to about 484 KJ / mol of the carbon-fluorine bond strength of the fluororesin. In the present invention, the organic / inorganic hybrid copolymer emulsion has a glass transition temperature (Tg) of 25 to 45 DEG C for better stain resistance. If the glass transition temperature is lower than 25 ° C, the glass transition temperature may cause contamination to the contamination source. If the glass transition temperature is higher than 45 ° C, there is a risk of cracking of the coating film.

The inorganic or organic copolymer emulsion may be in the range of 40 to 60 parts by weight or 41 to 55 parts by weight in the coating composition. If the amount of the organic / inorganic hybrid emulsion is less than 40 parts by weight, the adhesion and durability of the coating film may be deteriorated. If the amount is more than 60 parts by weight, the coating film may become too soft or peeled.

In the organic / inorganic hybrid copolymer emulsion of the present invention, the acrylic monomer may be, for example, methyl methacrylate, butyl methacrylate, butyl acrylate, cyclohexane methacrylate, methacrylic acid, It is not. In the organic-inorganic hybrid copolymer emulsion of the present invention, the monomer containing an alkoxysilyl group or an epoxysilyl group may be, for example, an epoxy silane, methacryloxysilane, methyltrimethoxysilane, methacryloxypropyltrimethoxysilane, or a mixture thereof But is not limited thereto.

The aqueous acrylic coating composition as described above contains an inorganic or organic copolymer emulsion prepared by copolymerizing an acrylic monomer having excellent weatherability and a monomer containing an alkoxysilyl group or an epoxysilyl group as a binder to impart weather resistance and stain resistance to a conventional oil- Can be improved remarkably. In addition, because of its higher molecular weight than the oil-based acrylic resin, the coating film is flexible and robust and has excellent durability. In addition, it can minimize volatile organic compounds and is very environmentally friendly.

Further, the aqueous acrylic coating composition of the present invention can improve the flexibility and impact resistance of the coating film by including the above-mentioned elastic acrylic emulsion.

The elastic acrylic emulsion can be used as a flexible binder, and in this case, it has excellent elasticity due to its high elasticity. Accordingly, it can be easily applied to a wall surface with severe bending. In addition, the elastic acrylic emulsion is environmentally friendly and has an advantage that it is not discolored even when exposed to the outside air for a long period of time.

The elastic acrylic emulsion may be an aqueous emulsion comprising an elastic acrylic-ester copolymer resin emulsion. The acrylic-ester copolymer resin emulsion is an emulsion containing a resin in which an acrylic compound and an ester compound are copolymerized, and may have a solid content of 40 to 60% by weight. Examples of the monomer compound used in the copolymerization include 2-ethylhexyl acrylate, acrylic acid, methacrylic acid, methyl methacrylate, ethyl, methyl, butyl , 2-ethylhexyl ester, and the like can be used. The acryl-ester copolymer resin emulsion may be one in which Stryrene or the like is dispersed as a reinforcing agent for enhancing water resistance. The acrylic emulsion may include an acryl-ester copolymer resin, or an acryl-ester copolymer resin emulsion in which styrene is dispersed, or a styrene-acrylic ester copolymer resin.

The elastic acrylic emulsion may have a glass transition temperature (Tg) of -10 to 20 ° C and a pH of 7 to 10. When the glass transition temperature of the elastic acrylic emulsion is less than -10 캜, the strength of the coating film is lowered and the coating film becomes too soft and adherence may be deteriorated. When the glass transition temperature is more than 20 캜, And the impact resistance may be lowered. If the pH is less than 7, gelation may proceed during storage of the coating, and if the pH is more than 10, the stability of the elastic acrylic emulsion particles may decrease and the adhesion may deteriorate.

The elastic acrylic emulsion may be contained in an amount of 2 to 15 parts by weight or 4 to 11 parts by weight. If the content of the elastic acrylic emulsion is less than 2 parts by weight, flexibility and impact resistance of the coating film may be lowered, and if it exceeds 15 parts by weight, mechanical properties and weather resistance may be lowered.

Also, the mixing ratio of the organic / inorganic hybrid emulsion: elastic acrylic emulsion may be 1: 0.02 to 1: 0.50 by weight. When the mixing ratio in the above range is satisfied, the appearance, flexibility, weather resistance and impact resistance of the coating film can be remarkably improved.

In addition, the aqueous acrylic paint composition of the present invention may comprise a second pigment, and the second pigment may include a colored pigment and an extender pigment. The second pigment may be contained in an amount of 5 to 30 parts by weight, and the colored pigment and the extender pigment may be 4 to 15 parts by weight and 1 to 15 parts by weight, respectively. When the amount of the colored pigment is less than 4 parts by weight, there may be a problem of concealment failure. When the amount exceeds 15 parts by weight, the physical properties of the coating film may deteriorate and the cost may increase. If the amount of the extender pigment is less than 1 part by weight, the hardness of the coating film may be lowered, and if it exceeds 15 parts by weight, adhesion may be lowered or the cured coating film may cause microcracking and adversely affect water resistance.

Examples of the color pigments usable in the present invention include, but not limited to, titanium oxide, carbon black, phthalocyanine, and iron oxide, which are generally used in water-soluble top coatings. These can be used alone or in combination for color reproduction of the coating film.

The extender pigments that can be used in the present invention include, for example, calcium carbonate, silica, dolomite, talc, barium sulfate, kaolin, mica, wurathonite, chlorite, aluminum silicate, aluminum hydroxide Etc. may be used. These can be used alone or in combination for the purpose of manifesting the hardness and physical properties of the coating film.

Further, the aqueous acrylic coating composition of the present invention contains water as a main solvent. Water acts as a dispersant for each particle in the paint or as a solvent for various compounds. When water is added to the paint, it is also used as a diluent. In the present invention, 5 to 20 parts by weight of water may be contained in the coating composition. The water used as a main agent is a very important factor for the paint of the present invention to have environmentally friendly properties. In the present invention, water can be used, for example, pure water or deionized water.

Further, the aqueous acrylic composition of the present invention may further comprise a solvent. When the coating film is formed as a film forming aid, the solvent helps to melt the binder, making the coating more dense, and improving the wetting efficiency with respect to the substrate, thereby improving adhesion. In addition, the lowest film-forming temperature of the emulsion resin is lowered to help form the coating film of the water-soluble paint at a low temperature.

In the present invention, 5 to 10 parts by weight of the solvent may be included. If the amount of the solvent is less than 5 parts by weight, the film formation may be poor at a low temperature, and if it exceeds 10 parts by weight, the drying speed may be very slow. Examples of the solvent include Texanol, butyl carbitol, butyl cellosolve, and mixtures thereof.

In addition, the aqueous acrylic coating composition may contain various additives used in conventional coating compositions according to purposes, in addition to the above components.

The additives usable in the present invention may include, for example, at least one additive such as a dispersing agent, a surface modifier, a thickener, a defoaming agent, a humectant, a neutralizing agent, a surfactant and a thixotropic agent. In addition, the amount thereof to be used may be added in a usual amount, and may be variously used within a range similar to the additives used in the epoxy-based coating composition described above.

The aqueous acrylic coating composition may contain 40 to 60 parts by weight of an organic / inorganic hybrid copolymer emulsion, 2 to 15 parts by weight of an elastic acrylic emulsion, 5 to 30 parts by weight of a second pigment and 5 to 20 parts by weight of water, When satisfied, it is possible to optimize the physical properties of the coating film such as weather resistance as well as securing excellent appearance.

Further, the coating material kit of the present invention may further comprise an epoxy-based zinc coating composition. In the paint kit, the epoxy coating composition may be applied to the intermediate coating layer, the acrylic coating composition may be applied to the top coating layer, and if necessary, an epoxy-based zinc coating composition may be included for the undercoating layer have. In this case, the epoxy-based zinc coating composition may be prepared by mixing 5 to 15 parts by weight of an epoxy resin having two or more epoxy groups, 5 to 10 parts by weight of water, 1 to 5 parts by weight of pigment, 0.5 to 5 parts by weight of an amide curing agent, And 60 to 80 parts by weight of the powder.

In addition, the present invention provides a multilayer coating film using the coating material kit. That is, the multilayer coating film according to the present invention is a multilayer coating film painted on a substrate, which comprises an aqueous epoxy coating layer and an aqueous acrylic coating layer sequentially on the aqueous epoxy coating layer, wherein the epoxy coating layer comprises two An acrylic emulsion, an amide curing agent, a first pigment, and water, and the aqueous acrylic coating layer is a layer formed of an organic-inorganic hybrid copolymer emulsion, an elastic acrylic emulsion, a water- A second pigment, and water may be coated and formed.

The substrate may be a substrate comprising a coating layer on which various undercoating compositions are coated, and may comprise, for example, an epoxy-based zinc coating layer.

The epoxy-based zinc paint layer comprises 5 to 15 parts by weight of an epoxy resin having two or more epoxy groups, 0.5 to 5 parts by weight of an amide curing agent and 60 to 80 parts by weight of zinc powder, 5 to 10 parts by weight of water and 1 to 5 parts by weight of a pigment Based zinc paint composition may be coated and formed. The epoxy-based zinc coating composition may further comprise 5 to 15 parts by weight of a solvent and 1 to 5 parts by weight of an additive.

Examples of the epoxy resin having two or more epoxy groups contained in the epoxy-based zinc paint layer include phenol novolak-type epoxy resin, cresol novolak-type epoxy resin, trishydroxyphenylmethane-type epoxy resin, dicyclopentadiene phenol Type epoxy resin, bisphenol-A type epoxy resin, bisphenol-F type epoxy resin, biphenol-type epoxy resin, bisphenol-A novolak type epoxy resin, naphthalene skeleton-containing epoxy resin, glyoxal type epoxy resin, heterocyclic epoxy resin, etc. Specifically, the bisphenol A-modified epoxy emulsion resin may have an epoxy equivalent of 950 to 1050 g / eq. If it is outside this range of equivalence, it may be because it affects the crosslinking density and finally affects the physical properties such as the anti-corrosive property and adhesion property of the paint. Further, in order to secure mechanical properties such as crack resistance and impact resistance, a flexible resin having a resin Tg of -5 to 0 占 폚 can be used.

The curing agent contained in the epoxy-based zinc paint layer includes an amine in which methylene is bonded to an alicyclic amine or aromatic amine hydrogenated with polyamide and aniline. Examples of the curing agent include polyamide and methylene bridged (1) selected from the group consisting of poly (cyclohexyl-aromatic) amine (MPCA), [5,2,1,0] -tricyclodecane-2,6-bis-hexamethylenediamine and methylenedianiline May be a polyamide resin containing more than one species. In addition, the curing agent may have an activated hydrogen equivalent of 60 to 80 g / eq and a solid content of 85 to 100%. The pigment may be dispersed in the curing agent to improve the dispersibility, and various extender pigments, colored pigments and the like which are conventionally used may be used.

The zinc powder contained in the epoxy-based zinc paint layer should have a purity of 95% or more. The subject of the present invention is to use only isopropyl alcohol or an alcohol-based or mineral oil-free agent to suppress the oxidation reaction of zinc powder And water can be used for the curing agent. In addition, various coating compositions can be applied as long as the coating composition of the undercoating layer on which the aqueous epoxy coating composition can be coated does not impair the physical properties.

The aqueous epoxy coating composition applied to the aqueous epoxy coating layer comprises 30 to 35 parts by weight of an epoxy resin having two or more epoxy groups, 3 to 10 parts by weight of an acrylic emulsion, 1 to 5 parts by weight of an amide curing agent, 28 to 55 parts by weight of water and 5 to 20 parts by weight of water, wherein the aqueous acrylic coating composition coated on the aqueous acrylic coating layer comprises 40 to 60 parts by weight of an organic / inorganic hybrid emulsion, 2 to 15 parts by weight of an elastic acrylic emulsion, 5 to 30 parts by weight of 2 pigment and 10 to 20 parts by weight of water. In the case of a multi-layer coating film comprising an aqueous epoxy coating layer and an aqueous acrylic coating layer blended in the above range, it is possible to realize remarkably excellent rust resistance and weather resistance by using a water-soluble coating composition as compared with a multi-layer coating film comprising a solvent coating layer.

In the multi-layer coating film of the present invention, based on the dry film thickness, the aqueous epoxy coating layer is in the range of 30 to 50 占 퐉, or 35 to 45 占 퐉, and the aqueous acrylic coating layer is 30 to 50 占 퐉 or 35 to 45 M < / RTI > In addition, when the base layer includes a lower paint layer, for example, an epoxy-based zinc paint layer, the thickness of the epoxy-based zinc paint layer is in the range of 10 to 30 탆 or 15 to 25 탆, .

Further, the present invention provides a method for forming the multilayer coating film.

The present invention relates to a process for producing a water-based epoxy coating composition comprising coating and drying an aqueous epoxy composition coating composition comprising an epoxy resin, an acrylic emulsion, an amide curing agent, a first pigment and water having two or more epoxy groups on a substrate, And coating an aqueous acrylic coating composition containing an organic-inorganic hybrid emulsion, an elastic acrylic emulsion, a second pigment, and water on the aqueous epoxy coating layer to form an aqueous acrylic coating layer.

In the method for forming a multilayer coating film, the aqueous epoxy coating layer may be formed using an aqueous epoxy coating composition having a combination of components in the above-mentioned content ranges. For example, the aqueous epoxy coating composition is coated on a substrate including a substrate or a primer coating layer to have a dry film thickness of 30 to 50 탆, and then left at room temperature for 1 minute to 10 minutes to form an aqueous epoxy coating layer Can be obtained.

Next, the aqueous acrylic coating layer can be formed using an aqueous acrylic coating composition having a combination of components in the above-mentioned content ranges. For example, the aqueous acrylic coating composition may be coated on the aqueous epoxy coating layer in an amount of 30 to 50 Lt; RTI ID = 0.0 > m, < / RTI > to form an aqueous acrylic coating layer.

The coating method usable for forming the multilayer coating film of the present invention can be formed by coating using a coating method well known in the art using, for example, air spray, airless spray, roller, brush or the like.

The multi-layer coating film formed using the coating kit of the present invention sequentially contains an aqueous epoxy coating layer and an aqueous acrylic coating layer formed by coating each of the aqueous epoxy coating composition and the aqueous acrylic coating composition having a specific combination of components, Excellent appearance and coating workability can be exhibited, and at the same time physical properties such as adhesion, rust prevention and weather resistance can be improved at the same time.

Accordingly, the coating material kit of the present invention and the multi-layer coating film using the coating material kit can be used for various container coatings, and the physical properties required by the International Institute of Container Lessors (IICL) can be easily achieved.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention.

Example

Example 1

Manufacture of paint kits

≪ Modification: Preparation of aqueous epoxy coating composition >

The contents and components of Table 1 were used.

First, 1 part by weight and 0.5 part by weight of a dispersant (EVONIK) and a wetting agent (EVONIK) were added to 8 parts by weight of water, 14 parts by weight of TiO ₂ (DUPONT, DUPONT, R-706) 15 parts by weight of barium sulfate, 14 parts by weight of barium sulfate and 2 parts by weight of zinc aluminum phosphate (HEUBACH Co., HEUCOPHOS ZPA) were dispersed in a high speed dissolver until the particle size became 50 μm . Subsequently, 35 parts by weight of a bisphenol A-modified epoxy resin, 4 parts by weight of an acrylic emulsion as an auxiliary resin, and 1 part by weight of a defoaming agent were added to prepare a subjecting agent having a viscosity of 100 KU as a thickener.

In the curing agent part, 1 part by weight of an amide resin (equivalent to an activated hydrogen equivalent of 75 g / eq) was mixed with 0.5 part by weight of isopropyl alcohol and then dissolved in 3.4 parts by weight of water to prepare an aqueous epoxy coating composition.

≪ Phase: Preparation of aqueous acrylic coating composition >

Preparation of organic / inorganic hybrid emulsion

i) Step 1

50 g of ion-exchanged water, 25 g of methyl methacrylate, 10 g of butyl acrylate, 10 g of butyl methacrylate, 5 g of cyclohexane methacrylate, 10 g of SR1025 (? -Sulfo-? - (1- (Ammonium salt of alkoxy) methyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2-ethane-di-yl), Adeka) and 0.15 g of potassium persulfate, Was heated to 80 DEG C and then reached 80 DEG C for about 60 minutes to prepare a seed emulsion polymer.

ii) Step 2

500 g of ion-exchanged water, 500 g of SR1025 (ammonium salt of alpha -sulfo-omega- (1- (alkoxy) methyl-2- (2- propenyloxy) ethoxy) -poly 8 g of sodium methacrylate, Adeka), 200 g of methyl methacrylate, 60 g of butyl acrylate, 60 g of butyl methacrylate, 40 g of cyclohexane methacrylate, 40 g of methacrylic acid, 15 g of methyltrimethoxysilane, 5 g of silane and 1.2 g of potassium persulfate were added and stirred to prepare a pre-emulsion. The pre-emulsion was continuously fed into the reactor for 3 hours and maintained at 80 ° C for 1 hour to prepare a core emulsion.

iii) Step 3

After the holding time, the mixture was cooled to 40 ° C, and 4.5 g of ammonia water was added thereto, followed by maintaining the temperature for 2 hours to prepare a stable core emulsion.

Preparation of aqueous acrylic paint composition

17 parts by weight of water, a surfactant (APEO free), a thickener and an antifoaming agent were added to the rustless container, and the mixture was stirred for about 30 minutes, and then the dispersing agent was added thereto and stirred again for 5 minutes. Subsequently, 12 parts by weight of the extender silica pigment and 5 parts by weight of titanium oxide were added with gentle stirring, and the mixture was dispersed for 15 minutes by increasing the number of revolutions per minute so that the linear velocity of the impeller edge of the agitator was 18-21 m / s, .

While slowly stirring the dispersed mill base, 55 parts by weight of the organic / inorganic hybrid copolymer emulsion and 2 parts by weight of the elastic acrylic emulsion were slowly added thereto and stirred for 10 minutes. Seven parts by weight of texanol as a solvent was added thereto, followed by stirring for about 10 minutes . As a result, an aqueous acrylic coating composition was obtained.

<Preparation of Epoxy-Based Zinc Coating Composition>

First, 21 parts by weight of a bisphenol A-modified epoxy emulsion (HEXION, epoxy equivalent: 1000 g / eq) and 0.1 parts by weight of sodium nitrite (BASF, sodium ritrite) as a flash rust inhibitor were prepared. 0.9 part by weight of an amide resin (equivalent to an activated hydrogen equivalent of 73 g / eq), 65 parts by weight of zinc powder, 0.1 part by weight of dispersing agent, 3 parts by weight of talc (Kyonggi Industry, 3-5 탆), 10 parts by weight of isopropyl alcohol . This mixture was dispersed with a high speed dispersion stirrer until the particle size became 20 탆 to obtain an epoxy-based zinc coating composition.

&Lt; Preparation of multilayer coating film &

The epoxy-based zinc coating composition (undercoat), the aqueous epoxy coating composition (middle) and the aqueous acrylic coating composition (topcoat) were sequentially applied to a 1.6T cold-rolled steel sheet in a dry film thickness of 20 μm / 40 μm / After coating, it was dried at a temperature of 23 ± 2 ° C and a relative humidity of 50 ± 10%. At this time, ventilation of the inside of the drying chamber was performed so that strong wind was not directly applied to the surface of the coated film.

Examples 2 to 10

An epoxy-based zinc coating composition (undercoat), an aqueous epoxy coating composition (intermediate), and an aqueous acrylic coating composition (top coat) were prepared in the same manner as in Example 1 except that the content of each composition was changed as shown in Table 1 below. ) And a multilayer coating film using the same.

Comparative Example 1

The procedure of Example 1 was repeated to prepare an epoxy-based zinc coating composition (primer), an aqueous epoxy coating composition (coating composition), and an aqueous epoxy coating composition (Intermediate) and an aqueous acrylic coating composition (top coat) and a multilayer coating film using the same.

Comparative Example 2

Except that an acrylic urethane water-dispersible resin (KCC) was used in place of the elastic acrylic emulsion in the aqueous acrylic coating composition (top) as shown in Table 2 below, to obtain an epoxy-based zinc coating composition ), An aqueous epoxy coating composition (intermediate) and an aqueous acrylic coating composition (top coating), and a multilayer coating film using the same.

Comparative Example 3

An epoxy-based zinc coating composition (undercoat) was prepared in the same manner as in Example 1, except that the urethane water-dispersible resin (KCC) was used instead of the elastic acrylic emulsion in the aqueous acrylic coating composition (top) , An aqueous epoxy coating composition (intermediate) and an aqueous acrylic coating composition (top coating), and a multilayer coating film using the same.

Reference example

Using the same materials as those of the examples and comparative examples of the present invention, a multilayer coating film using conventional oil-based paints (middle and top) was obtained.

division ingredient Example One 2 3 4 5 6 7 8 9 10 Aqueous epoxide
clock
Paint composition
(Midway) Suzy BPA modified epoxy resin 35 35 35 35 35 35 32 33 37 39 Acrylic emulsion 4 4 4 4 4 4 10 9 5 3 water Deionized water 11.4 11.4 11.4 11.4 11.4 11.4 11.4 11.4 11.4 11.4 additive Dispersant One One One One One One One One One One Wetting agent 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Thickener
(DOW, RM-8W) 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 Defoamer One One One One One One One One One One The first pigment TiO ₂ 14 14 14 14 14 14 13 13 13 13 Talc 15 15 15 15 15 15 14 14 14 14 Barium sulfate 14 8 12 12 12 12 11 11 11 11 Zinc aluminum phosphate 2 8 4 4 4 4 4 4 4 4 Hardener Amide resin One One One One One One One One One One solvent Isopropyl alcohol 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5




Water-based acrylic
Paint composition
(normal course) Suzy Organic / inorganic hybrid emulsion 55 55 52 49 46 43 53 53 53 53 Elastic acrylic emulsion 2 2 5 8 11 14 4 4 4 4 water Deionized water 17 17 17 17 17 17 17 17 17 17 additive Surfactants
(Surfynol 104) One One One One One One One One One One Thickener
(Natrosol) 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Silicone defoamer 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Dispersant
(Disperbyk 190) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.1 2 Second pigment Silica 12 12 12 12 12 12 12 12 12 12 Titanium oxide 5 5 5 5 5 5 5 5 5 5 solvent Texan 7 7 7 7 7 7 7 7 7 7 <Midway>
(1) BPA modified epoxy resin: epoxy equivalent 1000 g / eq, solid content 55%, Tg = -3 ° C KCC Corp.
(2) Acrylic emulsion: Tg = -10 DEG C, weight average molecular weight 200,000 KCC
<Top>
(1) Organic / inorganic hybrid emulsion: Tg = 42 캜, weight average molecular weight 220,000, particle size 165.5 nm, solid content 45%
(2) Elastic acrylic emulsion: Styrene-acrylic ester copolymer emulsion, Tg = -4 DEG C, weight average molecular weight 180,000, solid content 50%

division Component ingredient Comparative Example One 2 3 Mercury
Epoxy system
Paint composition
(Midway) The same components and contents as in Example 3 Water-based acrylic
Paint composition
(normal course) Suzy Organic / inorganic hybrid emulsion (KCC, CHW00479) 57 52 52 Acrylic urethane water-dispersible resin
(KCC) - 5 - Urethane water-dispersible resin
(KCC) - - 5 water Deionized water 17 17 17 additive Surfactants
(Surfynol 104) One One One Thickener
(Natrosol) 0.2 0.2 0.2 Defoamer silicone defoamer 0.3 0.3 0.3 Dispersant Dispersive 190
(Disperbyk 190) 0.5 0.5 0.5 Second pigment Silica 12 12 12 Titanium oxide 5 5 5 solvent Texan 7 7 7

Experimental Example

Adhesion, corrosion resistance and color test were conducted according to the test methods of Tables 3 and 4 using the coatings obtained according to the above Examples and Comparative Examples, and the results are shown in Tables 3 and 4 below.

1) Adhesion: Evaluation according to ASTM D3359 (56 days) (5B (good) < - > 0B (poor))

2) Corrosion resistance: 10 (good) <-> 0 (poor)) 8 times in total (8 days in total, 16 days (4 days), 4 hours wet, 2 hours drying (4 days) evaluation based on ASTM D610)

3) Color difference E (ASTM D2244)

  : The color difference before and after the test is measured using a color computer

4) Gloss retention (ASTM D523)

 : The gloss retention rate was evaluated by measuring the gloss before and after the test with the reflectance when the angle of incidence and the light receiving angle were 60 ° using a glossmeter.

5) Rust Creepage (ISO20340)

- Measure the average width (mm, mm) of the rust from the scribe line.

- Formula: M = (C-W) / 2

    M: Rust occurred

    C: rust creep Average of rust creep width (9 point measurements)

    W: original width of the script (2mm)

6) Contamination resistance: The contamination resistance test was performed by contacting the coating film with contaminants for 4 hours and wiping with solvent. As a result, it was evaluated as Good ○, Normal ○, Insufficient X

7) Impact resistance: Evaluated according to ASTM D2794 (10 (good) <-> 0 (poor))

No Test Items  Test Methods Example Comparative Example One 2 3 4 5 6 7 8 9 10 One 2 3 One Attachment
(56 days) ASTM D3359 4B 4B 4B 5B 5B 5B 4B 5B 4B 3B 3B 3B 4B 2 Corrosion resistance
(56 days) ASTM D610 6 9 9 9 9 8 7 9 9 9 6 7 6 3 Color difference (E)) ASTM D2244 0.9 1.0 1.0 1.0 1.1 1.1 1.0 1.0 1.0 1.0 1.0 1.0 1.1 4 Gloss retention (%) ASTM
D523 82 82 81 81 79 78 79 80 77 82 75 75 74 5 Rust Generation (mm) ISO20340 2.5 2.2 2.1 2.1 2.1 2.2 2.2 2.3 2.1 2.1 2.6 2.5 2.6 6 Stain resistance Decontamination ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ △ △ △ 7 Impact resistance ASTM D2794 8 8 8 9 10 10 9 9 9 8 5 7 6

No Test Items  Test Methods Reference example
(Existing oil paint)
Midway KCC
EP170
Sangdo KCC AH2470 One Attachment
(56 days) ASTM D3359 5B 2 Corrosion resistance
(56 days) ASTM D610 9 3 Color difference (E)) ASTM D2244 0.7 4 Gloss retention (%) ASTM
D523 80 5 Rust Generation (mm) ISO20340 2.1 6 Stain resistance Decontamination ○ 7 Impact resistance ASTM D2794 10

As shown in Tables 3 and 4, in the case of the multilayer coating formed according to the embodiment of the present invention, the remarkable improvement in physical properties can be confirmed as compared with the comparative example, and the multilayer coating using the conventional oily coating (Reference Example) It was confirmed that the physical properties were equal or higher.

Claims (9)

An aqueous epoxy composition coating composition comprising an epoxy resin having at least two epoxy groups, an acrylic emulsion, an amide curing agent, a first pigment and water,
An organic acrylic copolymer emulsion, an inorganic / organic copolymer emulsion, an elastic acrylic emulsion, a second pigment, and water.
The method according to claim 1,
The aqueous epoxy coating composition comprises 20 to 40 parts by weight of an epoxy resin having two or more epoxy groups, 3 to 10 parts by weight of an acrylic emulsion, 1 to 5 parts by weight of an amide curing agent, 28 to 55 parts by weight of a first pigment, By weight,
Wherein said aqueous acrylic coating composition comprises 40 to 60 parts by weight of an organic / inorganic hybrid copolymer emulsion, 2 to 15 parts by weight of an elastic acrylic emulsion, 5 to 30 parts by weight of a second pigment and 5 to 20 parts by weight of water.
The method according to claim 1,
Wherein the mixing ratio of the organic / inorganic hybrid emulsion: elastic acrylic emulsion is 1: 0.02 to 1: 0.50 by weight.
The method according to claim 1,
Wherein the mixing ratio of the epoxy resin: acrylic emulsion having two or more epoxy groups is 1: 0.1 to 1: 0.35 by weight.
The method according to claim 1,
The epoxy resin having two or more epoxy groups has a solid content of 50 to 60% by weight and an epoxy equivalent of 950 to 1050 g / eq,
Wherein the acrylic emulsion has a solid content of 40 to 60 wt% and a glass transition temperature (Tg) of -20 to 20 DEG C.
The method according to claim 1,
Wherein the organic / inorganic hybrid copolymer emulsion is an aqueous emulsion resin comprising an acrylic monomer and a monomer containing an alkoxysilyl group or an epoxy silyl group.
A multi-layer coating film coated on a substrate, which comprises an aqueous epoxy coating layer and an aqueous acrylic coating layer on the aqueous epoxy coating layer,
The epoxy-based coating layer is a layer formed by coating an aqueous epoxy coating composition containing an epoxy resin having two or more epoxy groups, an acrylic emulsion, an amide curing agent, a first pigment and water,
Wherein the aqueous acrylic coating layer is a layer formed by coating an aqueous acrylic coating composition containing an organic-inorganic hybrid emulsion, an elastic acrylic emulsion, a second pigment, and water.
The method of claim 7,
The aqueous epoxy coating composition comprises 20 to 40 parts by weight of an epoxy resin having two or more epoxy groups, 3 to 10 parts by weight of an acrylic emulsion, 1 to 5 parts by weight of an amide curing agent, 28 to 55 parts by weight of a first pigment, By weight,
Wherein the aqueous acrylic coating composition comprises 40 to 60 parts by weight of an organic / inorganic hybrid emulsion, 2 to 15 parts by weight of an elastic acrylic emulsion, 5 to 30 parts by weight of a second pigment and 5 to 20 parts by weight of water.
Coating and drying an aqueous epoxy composition coating composition containing an epoxy resin, an acrylic emulsion, an amide curing agent, a first pigment and water having at least two epoxy groups on a substrate to form an aqueous epoxy coating layer; and
Coating a water-based acrylic paint composition comprising an organic-inorganic hybrid emulsion, an elastic acrylic emulsion, a second pigment and water on the aqueous epoxy coating layer to form an aqueous acrylic coating layer; Way.