KR102044536B1 - Coating kit, multi-layered film using the same, and method of forming the same - Google Patents

Abstract

The present invention provides a paint kit comprising an aqueous epoxy paint composition and an aqueous acrylic paint composition, a multilayer coating film using the same, and a method of forming the same.

Description

Paint kit, multilayer coating using same and method for forming the same {COATING KIT, MULTI-LAYERED FILM USING THE SAME, AND METHOD OF FORMING THE SAME}

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

In general, epoxy coating zinc coating, epoxy coating, and acrylic coating coating compositions have been widely used for container coating. The main purpose of each paint is to protect the base and protect the corrosion of epoxy zinc undercoat, and in the case of epoxy intermediate, it is required to have adhesion and antirust performance as a role that connects between top and top. do. Finally, in the case of the acrylic top coat to be painted, the main purpose is to secure the appearance and weather resistance.

For this purpose, oil paint compositions have been conventionally used as the undercoat, midway and topcoat compositions. However, recently, with increasing interest in the environment and energy around the world, there is a growing movement to restrict the use of organic solvents (or volatile organic compounds) derived from fossil raw materials. Are being prepared or implemented.

In order to meet these demands, it is necessary to develop various environmentally friendly water-soluble paints while surpassing the physical properties of existing oil-based paint compositions.

Republic of Korea Patent Application Publication No. 2016-0077983

The present invention provides a paint kit.

The present invention also provides a multilayer coating film comprising the paint 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 acrylic emulsion, an amide curing agent, an aqueous epoxy coating composition comprising a first pigment and water, and an organic-inorganic composite copolymer emulsion, an elastic acrylic emulsion, a second pigment and water. It provides a paint kit comprising an aqueous acrylic paint composition.

In addition, the present invention is a multilayer coating film comprising a water-based epoxy paint layer and a water-based acrylic paint layer on the water-based epoxy paint layer sequentially on the substrate, the epoxy paint layer is an epoxy resin having two or more epoxy groups, A layer formed by coating an aqueous epoxy-based coating composition comprising an acrylic emulsion, an amide curing agent, a first pigment and water, and the aqueous acrylic coating layer includes an organic-inorganic composite copolymer emulsion, an elastic acrylic emulsion, a second pigment, and water. It provides a multilayer coating film which is a layer formed by coating the aqueous acrylic coating composition.

In addition, the present invention is to coat and dry an aqueous epoxy 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 to form an aqueous epoxy coating layer And coating and drying an aqueous acrylic coating composition comprising an organic-inorganic composite copolymer emulsion, an elastic acrylic emulsion, a second pigment, and water on the aqueous epoxy coating layer to form an aqueous acrylic coating layer. It provides a formation method.

The paint kit of the present invention includes an aqueous epoxy paint composition and an aqueous acrylic paint composition having a specific component combination, thereby achieving physical properties equivalent to or higher than those of the oil paint used in the conventional multilayer coating film. In addition, an environmentally friendly multilayer coating film can be formed, and the multilayer coating film formed thereby can exhibit excellent appearance and painting workability and can improve coating film properties such as adhesion, rust resistance, and weather resistance.

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

The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best explain their invention in the best way possible. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

The paint kit of the present invention is an epoxy resin having at least two epoxy groups, an acrylic emulsion, an amide curing agent, an aqueous epoxy coating composition and an organic-inorganic composite copolymer emulsion comprising a first pigment and water, an elastic acrylic emulsion, a second pigment and It is characterized by including an aqueous acrylic coating composition containing water.

The paint kit of the present invention comprises an aqueous acrylic coating composition comprising an elastic acrylic emulsion and an aqueous epoxy coating composition having a specific ingredient formulation, thereby providing excellent anti-corrosion and weather resistance equivalent to or higher than that of a conventional oil-based coating using a water-soluble coating. It can be implemented, and can form a multilayer coating film having an environmentally friendly and excellent appearance.

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

The paint kit of the present invention is an environmentally friendly paint kit, and includes an aqueous epoxy paint composition and an aqueous acrylic paint composition.

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

The epoxy coating composition may include an epoxy resin having two or more epoxy groups in order to secure excellent adhesion and rust resistance. For example, a phenol novolak-type epoxy resin, a cresol novolak-type epoxy resin, a tris hydroxyphenylmethane type epoxy resin, a dicyclopentadiene phenol type epoxy resin, a bisphenol-A type epoxy resin, a bisphenol-F type epoxy resin, A biphenol type epoxy resin, a bisphenol-A novolak type epoxy resin, a naphthalene skeleton containing epoxy resin, a glyoxal type epoxy resin, a heterocyclic epoxy resin, etc. can be used, but it is not limited to this. 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, it may be 20 to 40 parts by weight or 30 to 35 parts by weight. When the content of the epoxy resin having two or more epoxy groups is less than 20 parts by weight, water resistance, impact resistance may be lowered, and when it exceeds 40 parts by weight, adhesion, corrosion resistance, and chemical resistance may be deteriorated.

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 wt%. If it is out of such an equivalent range, it may affect the crosslinking density, which may adversely affect the coating properties such as rust resistance or adhesion of the paint. In addition, in order to secure mechanical properties such as crack resistance and impact resistance, the epoxy resin may use a flexible resin having a softening point of -5 to 0 ° C, but is not limited thereto.

In addition, the water-based epoxy paint composition may include an acrylic emulsion as an auxiliary resin to secure impact resistance.

The acrylic emulsion may be included in an amount of 3 to 10 parts by weight, or 3 to 9 parts by weight, and may satisfy the above range and may implement excellent impact resistance. In addition, the acrylic emulsion has a glass transition temperature (Tg) of -20 to 20 ° C, a weight average molecular weight of 150,000-300,000g / mol, an average particle size of 100-300nm, a pH of 7 to 10, and a solid content This can be 40 to 60% by weight. When the glass transition temperature of the acrylic emulsion is less than -20 ℃, the strength of the coating film is lowered and the coating film is too flexible, the adhesion may be reduced, when the glass transition temperature is more than 20 ℃, the strength of the coating film is too hard Impact resistance may be lowered. In addition, when the pH is less than 7, gelation may proceed during the storage of the paint, and when the pH is more than 10, the stability of the acrylic emulsion particles may be lowered, thereby lowering the adhesion.

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

In addition, the water-based epoxy paint composition may include an amide curing agent to secure the adhesion, low temperature drying, flexibility and rust prevention.

The amide curing agent includes an amine in a form in which methylene is bonded to an alicyclic amine or an aromatic amine hydrogenated to polyamide and aniline, and for example, polyamide and methylene crosslinked poly (cyclohexyl-aromatic) amine ( MPCA), [5,2,1,0] -tricyclodecane-2,6-bis-hexamethylenediamine, may be a polyamide resin containing at least one selected from the group consisting of methylenedianiline (MDA) have. In addition, the amide curing agent may be 70-80 g / eq active hydrogen equivalent, the solid content is 35 to 45% by weight, the amine is 300 to 500mg KOH / g. When the hydride hydrogen hydride equivalent of the amide curing agent is less than the above range, the water resistance and rust preventing property may be inferior, and when it exceeds the above range, the viscosity may be too high and the spray workability may be inferior.

In the present invention, the amide curing agent may include 1 to 5 parts by weight in the coating composition.

In addition, the water-based epoxy paint composition may include a first pigment to improve the color of the paint composition and the mechanical properties of the paint.

The first pigment may be a extender pigment, an rust preventive pigment, a color pigment, and the like, and may be used alone or in combination of two or more pigments.

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 generally used in water-soluble paints. have. These can be used individually or in mixture for expression of hardness, physical property, etc. of a coating film. The extender pigment may be included, for example, in an amount of 15 to 30 parts by weight, but may be used by mixing barum sulfate and talc within the above range, but is not limited thereto.

The colored pigment may be, for example, titanium oxide, carbon black, phthalocyanine, iron oxide, and the like, which are generally used in water-soluble paints, but is not limited thereto. These may be used alone or in combination for color development of the coating. The colored pigment may be included, for example, in an amount of 10 to 15 parts by weight, and may include titanium oxide in an amount in the above range.

In addition, the rust preventive pigments may be used to improve the 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. Can be. The rust preventive pigment may be included, for example, in an amount of 3 to 7 parts by weight.

The total content of the first pigment included in the aqueous epoxy paint composition may be 28 parts by weight to 55 parts by weight or 35 to 45 parts by weight. When the content of the first pigment is less than 28 parts by weight, it may lead to a reduction in hiding power of the coating film, and when it exceeds 55 parts by weight, the interlayer adhesion between the coating films and the clarity of the gloss and color may be reduced, and the mechanical properties may be deteriorated. In addition, it can provide a reason for the price increase of the paint.

In addition, the aqueous epoxy coating composition contains water as the main solvent. Water acts as a solvent for the dispersion medium or various compounds of each particle in the paint, and is also used as a diluent when added to the paint. In the present invention, water may be included in the coating composition 5 to 20 parts by weight. Water used as the main solvent is a very important factor for the environmentally friendly paints of the present invention. In the present invention, water may be used, for example, pure water or deionized water.

In addition, the aqueous epoxy composition may further include a solvent in addition to water. In the present invention, when the coating film is formed, the solvent helps to fusion of the binder, thereby making the coating film more dense and improving the wetting efficiency on the substrate, thereby improving adhesion.

In the present invention, the solvent may include 0.5 to 2.5 parts by weight. If the solvent is less than 0.5 parts by weight, the coating film formation may be poor at low temperatures, when the solvent exceeds 2.5 parts by weight may be very slow drying.

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

In addition, the water-based epoxy paint composition may include various additives used in conventional paint compositions according to the purpose in addition to the above components.

Additives usable in the present invention may include, for example, one or more additives such as dispersants, surface conditioners, thickeners, antifoams, wetting agents, neutralizing agents, surfactants and thixotropic modifiers. In addition, the amount to be used may also be added in an amount generally applied.

The dispersant is an additive used for dispersing the pigment, BYK's DISPERBYK-160, DISPERBYK-180, DISPERBYK-190 and DISPERBYK-199, etc., EVONIK's TEGO 752, TEGO 755 and TEGO 760 and the like can be used alone or in combination However, the present invention is not limited thereto, and an ionic or nonionic type may be selected and used.

The dispersant may be included in an amount of 0.1 to 2 parts by weight. When the content of the dispersing agent is less than 0.1 part by weight, the dispersion efficiency of the pigment is greatly reduced, causing re-agglomeration of the pigment, which may cause cregging in the coating film, poor polishing resistance and gloss of the coating film during application of the paint. . In addition, when the content of the dispersant exceeds 2 parts by weight, the excessive increase in transparency may cause a decrease in hiding power of the coating film and a price increase, as well as an increase in ionic groups in the coating film, thereby significantly reducing the water resistance of the coating film.

In addition, the surface modifier is an additive added to improve the smoothness of the paint, may include one or more selected from the group consisting of BYK-345, BYK-346, BYK-348 and BYK-349 of BYK, but is not limited thereto. It is not possible to use siloxane, silicon, or other polymer type materials that adjust the surface tension to improve the wettability of 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 flow of the paint, for example, DOW RW-8W, KUSUMOTO's AQ-607, AQH-800 and AQ633E, Hercules's Natrosol selected from the group consisting of Can be. The thickener may be included in an amount of 0.1 to 0.9 parts by weight.

In addition, the antifoaming agent may play a role of suppressing the generation of bubbles in the composition and at the same time inhibit the pinhole phenomenon generated when the coating film is dried. The antifoaming agent may be added to the entire amount during the manufacture of the paint, but a part may be first applied in the pigment aqueous dispersion manufacturing process in order to remove bubbles generated during the production of the pigment aqueous dispersion. The antifoaming agent may use a silicone antifoaming agent, and examples of commercialized products include Airproduct's DF-110D, Surfynol 104, and San Nopco's SN-DEFOAMER 1320, BYK's BYK-024 and BYK-028. The amount of the antifoaming agent may be included in an amount of 0.1 to 1.9 parts by weight. If the content of the antifoaming agent is less than 0.1 parts by weight may decrease the ability to suppress bubbles in the paint, if the content exceeds 1.9 parts by weight may cause a decrease in water resistance.

In addition, the humectant may be used to improve wettability, and for example, polyether modified siloxane (BYK349, BYK) may be used. The humectant may be included in an amount of 0.1 to 0.9 parts by weight. If the content of the humectant is out of the above range, the adhesion characteristics of the coating film may be lowered.

In addition, the neutralizing agent may be used by selecting one or more selected from formic acid, acetic acid, glacial acetic acid, lactic acid and aromatic sulfonic acid. The neutralizing agent may be included in an amount of 0.01 to 0.99 parts by weight.

Examples of the surfactant include Airprocut Surfynol 104, which does not contain alkylphenol ethoxylate (APEO), and the like. However, the thixotropic agent includes Natrosol, such as Hercules, but is not limited thereto.

The aqueous epoxy paint composition is 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 the first pigment and 5 to 20 of water. It may include parts by weight, and may be used as a middle paint composition when satisfying the above range, and at this time, it may exhibit excellent adhesion as a role of connecting the upper and upper coats, and may improve the anti-rust property as well as the coating properties. .

On the other hand, the paint kit of the present invention includes an aqueous acrylic paint composition to ensure excellent appearance and weather resistance, which can be attached on the water-based epoxy paint composition.

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

The organic-inorganic composite copolymer emulsion of the present invention is an aqueous emulsion resin containing an acrylic monomer and a monomer containing an alkoxy silyl group or an epoxy silyl group, and may be synthesized to be a siloxane crosslink in the acrylic main chain. The silyl groups in the main chain may be hydrolyzed to react with water during emulsion polymerization to form silanol, and then the silanol may be condensed to crosslink into a stable siloxane bond. This crosslinking can be carried out at room temperature, and the bonding force of the siloxane bond is about 443KJ / mol, which is comparable to about 484KJ / mol of the carbon-fluorine bonding force of the fluororesin. The organic-inorganic composite copolymer emulsion in the present invention has a glass transition temperature (Tg) of 25 to 45 ℃ for better fouling resistance. If the glass transition temperature is lower than 25 ℃ can be well polluted by the low glass transition temperature due to the contamination source, if it is higher than 45 ℃ may cause cracks in the coating film and a large amount of solvent may be used to solve this problem.

The organic-inorganic composite 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. When the organic-inorganic composite copolymer emulsion is less than 40 parts by weight, the adhesion and durability of the coating film may be lowered. When the organic-inorganic composite copolymer emulsion is less than 60 parts by weight, the coating film may become too flexible or may have problems such as peeling.

In the organic-inorganic complex copolymer emulsion of the present invention, for example, methyl methacrylate, butyl methacrylate, butyl acrylate, cyclohexane methacrylate, methacrylic acid or mixtures thereof may be used, but the present invention is not limited thereto. It is not. In the organic-inorganic composite copolymer emulsion of the present invention, the monomer containing the alkoxy silyl group or the epoxy silyl group may be, for example, epoxysilane, methacryloxysilane, methyltrimethoxysilane, methacryloxypropyltrimethoxysilane or mixtures thereof. May be used, but is not limited thereto.

The water-based acrylic paint composition includes an organic-inorganic composite copolymer emulsion prepared by copolymerizing an acrylic monomer having excellent weather resistance and a monomer containing an alkoxy silyl group or an epoxy silyl group as a binder, thereby providing weather resistance and stain resistance to conventional oil paints. It can be improved significantly. In addition, due to the higher molecular weight than the oil-based acrylic resin, the coating film is flexible and strong, and thus has excellent durability. In addition, it is very eco-friendly because it can minimize the volatile organic compounds.

In addition, the aqueous acrylic coating composition of the present invention can improve the flexibility and impact resistance of the coating film by including the elastic acrylic emulsion.

The elastic acrylic emulsion may be used as a flexible binder, in which case it has excellent flexibility due to the high elasticity. Accordingly, it can be easily constructed even on the wall with severe bends. In addition, the elastic acrylic emulsion is environmentally friendly, there is an advantage that does not discolor even when exposed to the outside air for a long 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 an acrylic compound copolymerized with an ester compound, the solid content may be 40 to 60% by weight. Monomer compounds used in the copolymerization include 2-ethylhexyl acrylate (2-Ethylhexyl acrylate), acrylic acid, methacrylic acid, methyl methacrylate and ethyl, methyl, butyl , At least one selected from 2-ethylhexyl ester and the like can be used. In addition, styrene (Stryrene) or the like may be dispersed in the acrylic-ester copolymer resin emulsion as a reinforcing agent for enhancing water resistance. The acrylic emulsion may include an acrylic-ester copolymer resin, or an acrylic-ester copolymer resin emulsion or a styrene-acrylic ester copolymer resin in which styrene is dispersed.

In addition, 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 ℃, the strength of the coating film is lowered, the coating film is too flexible, the adhesion may be lowered, if the glass transition temperature is more than 20 ℃, the strength of the coating film is too It may become hard and the impact resistance may fall. In addition, when the pH is less than 7, gelation may proceed during the storage of the paint, and when the pH is more than 10, the stability of the elastic acrylic emulsion particles may be lowered, thereby lowering the adhesion.

The elastic acrylic emulsion may be included in an amount of 2 to 15 parts by weight or 4 to 11 parts by weight. When 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 when it exceeds 15 parts by weight, mechanical properties and weather resistance may be lowered.

In addition, the mixing ratio of the organic-inorganic composite copolymer emulsion: elastic acrylic emulsion may be 1: 0.02 to 1: 0.50 weight ratio. When the mixing ratio of the above range is satisfied, the appearance, flexibility, weather resistance, impact resistance and the like of the coating film can be significantly improved.

In addition, the aqueous acrylic coating composition of the present invention may include a second pigment, the second pigment may include a color pigment and a extender pigment. The second pigment may be included in an amount of 5 to 30 parts by weight, and the colored pigment and the extender pigment may be in amounts of 4 to 15 parts by weight and 1 to 15 parts by weight, respectively. If the colored pigment is less than 4 parts by weight, there may be a problem of concealment, when the colored pigment is more than 15 parts by weight, there may be a problem of lowering the coating properties and cost. In addition, if the extender pigment is less than 1 part by weight, the hardness of the coating film may be lowered. If the extender pigment is more than 15 parts by weight, the adhesion may be slightly lowered or the cured coating film may cause microcracks, which may adversely affect the water resistance.

As the colored pigment usable in the present invention, titanium oxide, carbon black, phthalocyanine, iron oxide, and the like, which are generally used in water-soluble topcoats, may be used, but are not limited thereto. These may be used alone or in combination for color development of the coating.

The extender pigments usable in the present invention are, for example, calcium carbonate, silica, dolomite, talc, barium sulfate, kaolin, mica, wollastonite, chlorite, aluminum silicate and aluminum hydroxide, which are generally used in water-soluble topcoats. And the like can be used. These can be used individually or in mixture for expression of hardness, physical property, etc. of a coating film.

Moreover, the aqueous acrylic coating composition of this invention contains water as a main solvent. Water acts as a solvent for the dispersion medium or various compounds of each particle in the paint, and is also used as a diluent when added to the paint. In the present invention, water may be included in the coating composition 5 to 20 parts by weight. Water used as the main solvent is a very important factor for the environmentally friendly paints of the present invention. In the present invention, water may be used, for example, pure water or deionized water.

In addition, the aqueous acrylic composition of the present invention may further include a solvent. When the solvent is a film forming aid, when the coating film is formed, it helps the fusion of the binder to make the coating more dense and improve the wetting efficiency on the substrate, thereby improving adhesion. In addition, the minimum coating film formation 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, the solvent may include 5 to 10 parts by weight. When the solvent is less than 5 parts by weight, the coating film formation may be poor at low temperatures, when more than 10 parts by weight may be very slow drying rate. The solvent may be used, for example, Texanol, butyl carbitol, butyl cellosolve, and mixtures thereof.

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

Additives usable in the present invention may include, for example, one or more additives such as dispersants, surface conditioners, thickeners, antifoams, wetting agents, neutralizing agents, surfactants and thixotropic modifiers. In addition, the amount thereof may also be added in an amount generally applied, and may be variously used within a similar range as those used in the above-described epoxy paint composition.

The aqueous acrylic coating composition may include 40 to 60 parts by weight of the organic-inorganic composite copolymer emulsion, 2 to 15 parts by weight of the elastic acrylic emulsion, 5 to 30 parts by weight of the second pigment and 5 to 20 parts by weight of water, and the range When it is satisfied, it is possible to optimally improve coating properties such as weather resistance as well as securing excellent appearance.

In addition, the paint kit of the present invention may further include an epoxy-based zinc paint composition. In the paint kit, the epoxy paint composition may be applied for the middle paint layer, the acrylic paint composition may be applied for the top coat layer, and, if necessary, the epoxy paint composition may be included for the paint coat layer. have. At this time, the epoxy-based zinc coating composition, for example, 5 to 15 parts by weight of 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 amide curing agent and zinc It may include 60 to 80 parts by weight of powder.

In addition, the present invention provides a multilayer coating film using the coating kit. That is, the multilayer coating film according to the present invention is coated on a substrate, and is a multilayer coating film sequentially comprising an aqueous acrylic paint layer on the aqueous epoxy paint layer and the aqueous epoxy paint layer, wherein the epoxy paint layers are two An aqueous epoxy coating composition comprising an epoxy resin, an acrylic emulsion, an amide curing agent, a first pigment, and water having the above epoxy group is coated and formed, and the aqueous acrylic coating layer is an organic-inorganic composite copolymer emulsion, an elastic acrylic emulsion, It may be a layer formed by coating an aqueous acrylic coating composition including a second pigment and water.

The substrate may be a substrate including a paint layer coated with various undercoat compositions, and may include, for example, an epoxy-based zinc paint layer.

The epoxy-based zinc paint layer is 5 to 15 parts by weight of an epoxy resin having two or more epoxy groups, 0.5 to 5 parts by weight of 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 pigment. It may be a layer formed by coating an epoxy-based zinc coating composition comprising. In addition, the epoxy-based zinc coating composition may further include 5 to 15 parts by weight of the solvent and 1 to 5 parts by weight of the additive.

The epoxy resin having two or more epoxy groups contained in the epoxy zinc coating layer is, for example, a phenol novolak type epoxy resin, a cresol novolak type epoxy resin, a trishydroxyphenylmethane type epoxy resin, or a dicyclopentadiene phenol. Epoxy resin, bisphenol-A epoxy resin, bisphenol-F epoxy resin, biphenol epoxy resin, bisphenol-A novolac epoxy resin, naphthalene skeleton-containing epoxy resin, glyoxal epoxy resin, heterocyclic epoxy resin, etc. It may be used, specifically, the bisphenol A modified epoxy emulsion resin may have an epoxy equivalent of 950 to 1050 g / eq. If it is out of this equivalent range may affect the crosslinking density and ultimately affect the physical properties such as rust resistance, adhesion of the paint. In addition, in order to secure mechanical properties such as crack resistance and impact resistance, a flexible resin having a resin Tg of −5 to 0 ° C. may be used.

In addition, the curing agent included in the epoxy-based zinc paint layer includes polyamines and amines in which methylene is bonded to an alicyclic amine or an aromatic amine hydrogenated to aniline, for example, polyamide and methylene crosslinking. Poly (cyclohexyl-aromatic) amine (MPCA), [5,2,1,0] -tricyclodecane-2,6-bis-hexamethylenediamine, 1 selected from the group consisting of methylenedianiline (MDA) It may be a polyamide resin containing more than one species. In addition, the curing agent may be an active hydrogen equivalent of 60 to 80 g / eq, solid content of 85 to 100%. The pigment may be dispersed in the curing agent to improve the dispersibility, it may be used a variety of conventional pigments, pigments and the like.

The zinc powder contained in the epoxy-based zinc paint layer is one having a purity of 95% or more, and the main material is manufactured only with a solvent such as isopropyl alcohol, alcohol, or mineral oil without water to suppress oxidation reaction of the zinc powder. In addition, water may be used for the curing agent. In addition, the coating composition of the undercoat layer which may be coated with the water-based epoxy coating composition may be applied to various coating compositions as long as the physical properties are not impaired.

In addition, the water-based epoxy paint composition coated on the water-based epoxy paint layer is 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, first pigment 28 to 55 parts by weight and 5 to 20 parts by weight of water, and the aqueous acrylic coating composition coated on the aqueous acrylic coating layer is 40 to 60 parts by weight of the organic-inorganic composite copolymer emulsion, 2 to 15 parts by weight of the elastic acrylic emulsion, 2 to 5 to 30 parts by weight of pigment and 10 to 20 parts by weight of water. In the case of the multilayer coating film including the water-based epoxy paint layer and the water-based acrylic paint layer blended in the above range, it is possible to implement remarkably superior rust resistance and weather resistance compared to the multilayer paint film including the oil paint layer using a water-soluble paint.

In the multilayer coating film of the present invention, the water-based epoxy paint layer has a thickness in the range of 30 to 50 μm, or 35 to 45 μm based on the dry film thickness, and the water-based acrylic paint layer is 30 to 50 μm or 35 to 45 μm. It may be in the thickness range of μm. In addition, when the base layer includes a bottom coating layer, for example, an epoxy zinc coating layer, the thickness of the epoxy zinc coating layer may be in the range of 10 to 30 μm or 15 to 25 μm based on the dry coating thickness. Can be.

Furthermore, this invention provides the formation method of the said multilayer coating film.

The present invention is to paint and dry an aqueous epoxy paint 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 of to form an aqueous epoxy paint layer, and It may include forming an aqueous acrylic coating layer by coating and drying an aqueous acrylic coating composition including an organic-inorganic composite copolymer emulsion, an elastic acrylic emulsion, a second pigment, and water on the aqueous epoxy coating layer.

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

Next, the aqueous acrylic paint layer may be formed using an aqueous acrylic paint composition having a component combination in the above-described content range. For example, the aqueous acrylic paint composition may be formed on the aqueous epoxy paint layer by 30 to 50. It can be coated to have a dry coating thickness of μm to form an aqueous acrylic paint layer.

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

The multilayered coating film formed by using the paint kit of the present invention sequentially includes an aqueous epoxy paint layer and an aqueous acrylic paint layer formed by coating an aqueous epoxy paint composition and an aqueous acrylic paint composition each having a specific content of a component combination, While showing excellent appearance and painting workability, it is possible to simultaneously improve coating properties such as adhesion, rust resistance and weather resistance.

Therefore, the paint kit of the present invention and the multilayer coating film using the same can be usefully used for various container coatings, and can easily achieve the properties required by the Institute of International Container Lessors (IICL).

Hereinafter, the present invention will be described in detail with reference to Examples. However, embodiments according to the present invention can be modified in many different 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 more completely explain the present invention to those skilled in the art.

Example

Example 1

Manufacture of paint kits

<Medium: Production of Water-Based Epoxy Coating Composition>

The contents and ingredients of Table 1 were used.

First, 1 part by weight and 0.5 parts by weight of a dispersant (EVONIK) and a wetting agent (EVONIK) were added to 8 parts by weight of water, and 14 parts by weight of TiO ₂ (DuPont, DUPONT, R-706), talc 3-5 μm) 15 parts by weight, barium sulfate 14 parts by weight, zinc aluminum phosphate (HEUCACHH, HEUCOPHOS ZPA) 2 parts by weight of a high speed dissolver (High Speed dissolver) to the dispersion until the dispersion was prepared to . Thereafter, 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 an antifoaming agent were prepared, and a main body was prepared such that the viscosity was 100 KU as a thickener.

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

Top coat: Production of an aqueous acrylic coating composition

Preparation of organic-inorganic complex copolymer emulsion

i) First step

In a reactor equipped with a stirrer, a thermometer and a condenser, 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, and SR1025 (α-sulfo-ω- (1- Ammonium salt of (alkoxy) methyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2-ethane-di-yl), 1 g of Adeka), 0.15 g of potassium persulfate After raising the temperature to 80 ℃ was maintained for about 60 minutes to reach 80 ℃ to prepare a seed (seed) emulsion polymer.

ii) the second step

500 g of ion-exchanged water, ammonium of SR1025 (α-sulfo-ω- (1- (alkoxy) methyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2-ethane-di-yl)) Salt, Adeka) 8 g, methyl methacrylate 200 g, butyl acrylate 60 g, butyl methacrylate 60 g, cyclohexane methacrylate 40 g, methacrylic acid 40 g, methyl trimethoxysilane 15 g, methacryloxypropyl trimethoxy 5 g of silane and 1.2 g of potassium persulfate were added thereto to prepare a preemulsion. The preemulsion was continuously added to the reactor for 3 hours, and then maintained at 80 ° C. for 1 hour to prepare a core emulsion.

iii) the third step

After the holding time was cooled to 40 ℃ and added 4.5g of ammonia water was maintained for 2 hours to prepare a stable core emulsion.

Preparation of Aqueous Acrylic Coating Composition

17 parts by weight of water, a surfactant (APEO free), a thickener, and an antifoam were added to the container which was not rusted, and after stirring for about 30 minutes, a dispersant was added and stirred for another 5 minutes. Subsequently, 12 parts by weight of the silica extender pigment and 5 parts by weight of titanium oxide were slowly added thereto, and when finished, the mill base was prepared by increasing the revolutions per minute so that the linear speed of the impeller edge of the stirrer was 18-21 m / s and dispersed for 15 minutes. .

While slowly stirring the dispersed millbase, 55 parts by weight of the organic-inorganic composite copolymer emulsion and 2 parts by weight of the elastic acrylic emulsion were slowly added thereto, and after stirring for 10 minutes, 7 parts by weight of texanol was added as a solvent, followed by stirring for about 10 minutes. . As a result, an aqueous acrylic coating composition was obtained.

<Substrate: Production of epoxy-based zinc coating composition>

First, a main part was prepared from 21 parts by weight of bisphenol A modified epoxy emulsion (HEXION, epoxy equivalent 1000 g / eq) and 0.1 part by weight of sodium nitrite (BASF) as a flash rust inhibitor. And the curing agent portion 0.9 parts by weight of amide resin (equivalent hydrogen hydrogen equivalent 73 g / eq), 65 parts by weight of zinc powder, 0.1 parts by weight of dispersant, 3 parts by weight of talc (curing business, 3-5 ㎛), 10 parts of isopropyl alcohol as a solvent Added wealth. This mixture was dispersed with a high-speed dispersion stirrer until the particle size became 20 µm to obtain an epoxy zinc coating composition.

<Multilayer coating film manufacturing>

The epoxy-based zinc coating composition (undercoat), the aqueous epoxy-based coating composition (middle) and the aqueous acrylic coating composition (top) were sequentially sprayed with a dry coating thickness of 20 μm / 40 μm / 40 μm on a 1.6T cold rolled steel sheet, respectively. After coating, it was dried at a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 10%. At this time, while the inside of the drying chamber is ventilated, strong wind is not directly in contact with the coating film surface.

Examples 2 to 10

Except for changing the content of each composition as shown in Table 1, and carried out in the same manner as in Example 1 epoxy-based zinc coating composition (undercoat), water-based epoxy coating composition (midway) and water-based acrylic coating composition (top coat ) And a multilayer coating film using the same.

Comparative Example 1

As shown in Table 2, except that only the organic-inorganic composite copolymer emulsion in the aqueous acrylic coating composition (top coat), was carried out in the same manner as in Example 1 epoxy-based zinc coating composition (bottom), water-based epoxy paint composition (Middle) and the aqueous acrylic coating composition (top coat) and the multilayer coating film using the same were obtained.

Comparative Example 2

As shown in Table 2, except for using an acrylic urethane water-dispersible resin (KCC Co., Ltd.) instead of an elastic acrylic emulsion in the aqueous acrylic coating composition (top coat), it was carried out in the same manner as in Example 1 epoxy-based zinc coating composition (undercoat ), An aqueous epoxy paint composition (midway), an aqueous acrylic paint composition (top coat), and a multilayer coating film using the same.

Comparative Example 3

As shown in Table 2, except that the urethane water-dispersible resin (KCC Co., Ltd.) instead of the elastic acrylic emulsion in the aqueous acrylic coating composition (top coat) was carried out in the same manner as in Example 1 epoxy-based zinc coating composition (bottom coat) , An aqueous epoxy paint composition (midway), an aqueous acrylic paint composition (top coat), and a multilayer coating film using the same were obtained.

Reference Example

The undercoat obtained the multilayer coating film using the conventional oil-based paints (midway and top coat), using the thing similar to the Example and comparative example of this application.

division ingredient Example One 2 3 4 5 6 7 8 9 10 Mercury Epoch
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 Humectant 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Thickener
(DOW Corporation, RM-8W) 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 Antifoam One One One One One One One One One One 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
(highway) Suzy Organic-inorganic complex copolymer 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 antifoam 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 Texanol 7 7 7 7 7 7 7 7 7 7 <Medium>
(1) BPA modified epoxy resin: epoxy equivalent 1000 g / eq, solid content 55%, Tg = -3 ℃ KCC
(2) Acrylic emulsion: Tg = -10 ℃, weight average molecular weight 200,000 KCC
<Top>
(1) Organic-inorganic composite copolymer emulsion: Tg = 42 ° C., weight average molecular weight 220,000, particle size 165.5 nm, solid content 45% KCC
(2) Elastic acrylic emulsion: styrene-acrylic ester copolymer resin emulsion, Tg = -4 ℃, weight average molecular weight 180,000, solid content 50% KCC

division Component ingredient Comparative example One 2 3 Mercury
Epoxy
Paint composition
(Midway) Same ingredients and contents as in Example 3 Water based acrylic
Paint composition
(highway) Suzy Organic-inorganic complex copolymer emulsion (KCC, CHW00479) 57 52 52 Acrylic Urethane Dispersion Resin
(KCC) - 5 - Urethane Dispersion Resin
(KCC) - - 5 water Deionized water 17 17 17 additive Surfactants
(Surfynol 104) One One One Thickener
(Natrosol) 0.2 0.2 0.2 Antifoam Silicone Defoamer 0.3 0.3 0.3 Dispersant Dispervic 190
(Disperbyk 190) 0.5 0.5 0.5 Second Pigment Silica 12 12 12 Titanium oxide 5 5 5 solvent Texanol 7 7 7

Experimental Example

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

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

2) Corrosion resistance: Evaluation based on ASTM D610 (4 hours wet, 2 hours dry 16 times (4 days) 8 times in total (56 days)) (10 (good) <-> 0 (bad))

3) Color Difference E (ASTMD2244)

  : Measure color difference before and after test by using color computer

4) Gloss Retention (ASTM D523)

 : Gloss retention rate is evaluated by measuring the gloss before and after the test by reflectance when the angle of incidence and the angle of receiving angle are 60 ° using a glossmeter.

5) Rust Creepage (ISO20340)

Measure the average width (mm, mm) of rust occurrences on the Scribe line.

Calculation: M = (C-W) / 2

    M: Rust

    C: Average of rust creep width, 9 point measurements

    W: original width of the script (2 mm)

6) Pollution resistance: Test the stain resistance by contacting the coating film with contaminants for 4 hours and wiping it with a solvent. As a result, it is good ○, usually △, insufficient X.

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

No Test Items  Test Methods Example Comparative example One 2 3 4 5 6 7 8 9 10 One 2 3 One Adhesion
(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 Glossiness retention rate (%) 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 Pollution 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
Top KCC Corporation AH2470 One Adhesion
(56 days) ASTM D3359 5B 2 Corrosion resistance
(56 days) ASTM D610 9 3 Color Difference (E)) ASTM D2244 0.7 4 Glossiness retention rate (%) ASTM
D523 80 5 Rust generation (mm) ISO20340 2.1 6 Pollution resistance Decontamination ○ 7 Impact resistance ASTM D2794 10

As shown in Table 3 and Table 4, in the case of the multilayer coating film formed according to the embodiment of the present invention, a significant improvement in physical properties can be confirmed in comparison with the comparative example, and compared with the multilayer coating film using a conventional oil paint (reference example). Even if it was equal or more, it was confirmed that the physical properties appear.

Claims (9)

An aqueous epoxy coating composition comprising an epoxy resin, an acrylic emulsion, an amide curing agent, a first pigment, and water having two or more epoxy groups; and
An aqueous acrylic coating composition comprising an organic-inorganic composite copolymer emulsion, an elastic acrylic emulsion, a second pigment and water,
The epoxy resin having two or more epoxy groups has an epoxy equivalent of 950 to 1050 g / eq,
The acrylic emulsion has a glass transition temperature (Tg) of -20 to 20 ℃ the paint kit.
The method according to claim 1,
The aqueous epoxy paint composition is 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 the first pigment and 5 to 20 of water. Including parts by weight,
The water-based acrylic paint composition is a paint kit comprising 40 to 60 parts by weight of the organic-inorganic composite copolymer emulsion, 2 to 15 parts by weight of the elastic acrylic emulsion, 5 to 30 parts by weight of the second pigment and 5 to 20 parts by weight of water.
The method according to claim 1,
The organic-inorganic complex copolymer emulsion: the mixing ratio of the elastic acrylic emulsion is 1: 0.02 to 1: 0.50 weight ratio.
The method according to claim 1,
The paint kit having a mixture ratio of the epoxy resin having two or more epoxy groups: acrylic emulsion is 1: 0.1 to 1: 0.35 weight ratio.
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,
The acrylic emulsion has a solid content of 40 to 60% by weight of the paint kit.
The method according to claim 1,
The organic-inorganic composite copolymer emulsion is a paint kit which is an aqueous emulsion resin containing an acrylic monomer and a monomer containing an alkoxy silyl group or an epoxy silyl group.
As a multilayer coating film coated on a base material and sequentially containing an aqueous acrylic paint layer on the aqueous epoxy paint layer and the aqueous epoxy paint layer,
The epoxy paint layer is a layer formed by coating an aqueous epoxy paint composition comprising an epoxy resin, an acrylic emulsion, an amide curing agent, a first pigment and water having two or more epoxy groups,
The aqueous acrylic paint layer is a layer formed by coating an aqueous acrylic coating composition comprising an organic-inorganic composite copolymer emulsion, an elastic acrylic emulsion, a second pigment and water,
The epoxy resin having two or more epoxy groups has an epoxy equivalent of 950 to 1050 g / eq,
Wherein the acrylic emulsion is a glass transition temperature (Tg) is -20 to 20 ℃ multilayer coating film.
The method according to claim 7,
The aqueous epoxy paint composition is 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 the first pigment and 5 to 20 of water. Including parts by weight,
The aqueous acrylic coating composition is a multilayer coating film comprising 40 to 60 parts by weight of the organic-inorganic composite copolymer emulsion, 2 to 15 parts by weight of the elastic acrylic emulsion, 5 to 30 parts by weight of the second pigment and 5 to 20 parts by weight of water.
Coating and drying an aqueous epoxy 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 to form an aqueous epoxy coating layer; and
Coating and drying an aqueous acrylic coating composition comprising an organic-inorganic composite copolymer emulsion, an elastic acrylic emulsion, a second pigment, and water on the aqueous epoxy coating layer to form an aqueous acrylic coating layer,
The epoxy resin having two or more epoxy groups has an epoxy equivalent of 950 to 1050 g / eq,
The acrylic emulsion has a glass transition temperature (Tg) is -20 to 20 ℃ how to form a multilayer coating film.