KR20220148466A - Water-soluble epoxy coating composition - Google Patents

Abstract

The present invention relates to a water-soluble epoxy coating composition which includes a first epoxy resin, a second epoxy resin, a vinyl aromatic oligomer, and an amine-based curing agent, and comprises a polyalkylene glycol-modified epoxy resin, in which the first epoxy resin has a glass transition temperature of 10 to 50℃, and the second epoxy resin has a glass transition temperature of -10 to -1℃.

Description

Water-based epoxy paint composition {WATER-SOLUBLE EPOXY COATING COMPOSITION}

The present invention relates to a water-based epoxy paint composition that can be applied to yard (external) painting because it can be quickly dried and cured at room temperature, has excellent storage stability, and has excellent workability due to an appropriate pot life.

Recently, due to the strengthening of environmental regulations in each country, the demand for eco-friendly paints such as regulation of the content of volatile organic compounds (VOC) in paints is increasing, and development of water-based paints instead of oil-based paints is being actively performed. In particular, in China, which accounts for more than 95% of global container production, as the government strengthened environmental regulations, from July 2016, all paints used inside production lines were converted to water-based paints. Water-based paints inside the production line are generally divided into external specifications for coating epoxy-based zinc undercoat, epoxy-based intermediate and acrylic topcoats, and internal specifications for coating epoxy-based zinc undercoat and epoxy-based topcoat. For example, Korean Patent Application Laid-Open No. 2013-0081047 (Patent Document 1) discloses a primer main agent comprising a low-viscosity liquid modified bisphenol A-type epoxy resin and a high-viscosity liquid bisphenol A-type epoxy resin; And a two-component primer coating composition comprising an amine curing agent is disclosed.

However, most of the conventional water-based paints are limited to the case where they are applied in an indoor production line environment, so there is a limit to their applicability. For example, for container repair paints painted in the yard (outside), oil-based paints have been applied until now due to the limitation that artificial drying conditions cannot be set.

Therefore, it is possible to quickly dry and harden at room temperature, so it can be applied to yard (external) painting, has the same quality as conventional oil-based paints, and research and development for an eco-friendly water-based paint is required.

Korean Patent Publication No. 2013-0081047 (published on: July 16, 2013)

Accordingly, the present invention provides an epoxy paint composition that can be applied to yard (external) painting because it can be quickly dried and cured at room temperature, has excellent storage stability, has excellent workability due to appropriate pot life, and is water-based and eco-friendly want to

The present invention comprises a first epoxy resin, a second epoxy resin, a vinyl aromatic oligomer and an amine-based curing agent,

The first epoxy resin has a glass transition temperature of 20 to 40 ℃,

The second epoxy resin provides a water-based epoxy paint composition comprising a polyalkylene glycol-modified epoxy resin having a glass transition temperature of -10 to -1 °C.

The water-based epoxy paint composition according to the present invention can be applied to yard (external) painting because it is quick-drying and fast-curing at room temperature, and has an appropriate pot life, so it has excellent workability and excellent storage stability.

In addition, the coating film prepared from the epoxy paint composition has excellent mechanical properties such as adhesion, impact resistance, rust prevention and abrasion resistance.

Hereinafter, the present invention will be described in detail.

In the present invention, the functional group such as 'epoxy equivalent' may be measured by a method well known in the art, for example, may be a value measured by a titration method or the like.

In addition, in the present invention, the "glass transition temperature" of the resin is measured by a conventional method known in the art, for example, it can be measured by differential scanning calorimetry (DSC) or the like.

In addition, in the present invention, the "weight average molecular weight" of the resin can be measured by a method well known in the art, for example, it can represent a value measured by a method such as GPC (gel permeation chromatograph).

The aqueous epoxy paint composition according to the present invention includes a first epoxy resin, a second epoxy resin, a vinyl aromatic oligomer, and an amine-based curing agent. The first epoxy resin and the second epoxy resin have different glass transition temperatures, and as described above, when a resin having a relatively high glass transition temperature is applied, the drying property is excellent, and a resin having a relatively low glass transition temperature is applied. Due to its excellent appearance, it can be painted even at room temperature, which is an external atmospheric environment.

first epoxy resin

The first epoxy resin is a main resin of the epoxy paint composition, and forms a coating film by reacting with an amine-based curing agent, and serves to improve properties of the prepared coating film, for example, quick-drying and quick-setting at room temperature. Specifically, the first epoxy resin has a higher glass transition temperature than the second epoxy resin, so that the coating film is hard, thereby reducing the surface drying time during painting in an external environment.

The first epoxy resin includes, for example, a bisphenol A-type epoxy resin, a bisphenol F-type epoxy resin, a novolak-type epoxy resin, a cresol-modified epoxy resin, an acrylic-modified epoxy resin, an isocyanate-modified epoxy resin, and a rubber-modified epoxy resin. can Specifically, the first epoxy resin may be an unmodified bisphenol A-type epoxy resin.

In addition, the first epoxy resin may have an epoxy equivalent weight (EEW) of 800 to 1,200 g/eq, or 900 to 1,100 g/eq. When the epoxy equivalent of the first epoxy resin is less than the above range, the density of the cured coating film after painting may be lowered, and thus the rust prevention property of the prepared coating film may be inferior. In addition, when the epoxy equivalent of the first epoxy resin is more than the above range, the viscosity of the composition is increased, the spreadability is inferior, and the coating film is formed unevenly, making it difficult to form a smooth coating film appearance.

The first epoxy resin may have a glass transition temperature (Tg) of 20 to 40 °C, or 28 to 33 °C. When the glass transition temperature of the first epoxy resin is less than the above range, the drying of the coating film is slowed and the coating film is soft. This may deteriorate and the coating film may be hard.

In addition, the first epoxy resin may be in the form of an aqueous dispersion having a solid content (NV) of 50 to 65% by weight based on the total weight of the resin. When the solid content of the first epoxy resin is less than the above range, it is difficult to design a high solid content of the final paint product, and when the same amount is applied, there is a problem that the swellability of the coating film is lowered, and exceeding the above range In this case, the viscosity of the paint increases, which may cause a problem in that it is difficult to secure smooth workability of the final paint product.

The first epoxy resin may be included in an amount of 15 to 35% by weight, or 20 to 30% by weight based on the total weight of the epoxy resin composition. When the content of the first epoxy resin is less than the above range, curing at room temperature is not possible due to lack of quick-drying and fast curing properties at room temperature of the composition. can

2nd epoxy resin

The second epoxy resin is an aqueous dispersion resin of the epoxy paint composition, and forms a coating film by reacting with an amine-based curing agent, and serves to control the pot life of the composition.

The second epoxy resin is a bisphenol A-type epoxy resin, a bisphenol F-type epoxy resin, a novolak-type epoxy resin, a cresol-modified epoxy resin, an acrylic-modified epoxy resin, an isocyanate-modified epoxy resin, a rubber-modified epoxy resin, and a polyalkylene glycol-modified epoxy. resin etc. are mentioned. Specifically, the second epoxy resin may be a polyalkylene glycol-modified epoxy resin.

For example, when an unmodified bisphenol A-type epoxy resin is used as the first epoxy resin, the coating composition of the present invention includes an unmodified bisphenol A-type epoxy resin and a polyalkylene glycol-modified epoxy resin. As described above, when the composition includes an unmodified bisphenol A-type epoxy resin and a polyalkylene glycol-modified epoxy resin, an appropriate viscosity is formed in the paint manufacturing process, thereby enabling smooth manufacture of the paint.

Specifically, as described above, when a polyalkylene glycol-modified epoxy resin is used as the second epoxy resin, it is possible to improve the compatibility in formulation and the storage stability of the paint by controlling the hydrophilic performance due to the hydrophilic group of the polyalkylene glycol resin, When mixed with a hardener, it is possible to form a working viscosity suitable for field application of the paint.

In this case, the polyalkylene glycol may have 2 to 5 carbon atoms, or 2 to 4 carbon atoms. That is, the polyalkylene glycol may be, specifically, polyethylene glycol, polypropylene glycol or polybutylene glycol. As described above, when an epoxy resin modified with polyalkylene glycol having a small number of carbon atoms is used as the second epoxy resin, the smooth dispersibility and low particle size required in the dispersion process of paint production by using the viscosity drop of the dispersion through the increase of the hydrophilic group There is an effect that can secure the level.

The second epoxy resin may have an epoxy equivalent weight (EEW) of 850 to 1,250 g/eq, or 950 to 1,150 g/eq. If the epoxy equivalent of the second epoxy resin is less than the above range, the water resistance may be poor due to the low density of the cured coating film, and if it exceeds the above range, the viscosity of the composition increases and the spreadability of the paint becomes inferior and the coating film is formed unevenly It becomes difficult to form a smooth coating film appearance.

In addition, the second epoxy resin may have a glass transition temperature (Tg) of -10 to -1 °C, or -5 to -1 °C. When the glass transition temperature of the second epoxy resin is less than the above range, there is a problem in that the pot life is slow, and when it exceeds the above range, the flexibility and anti-sagging properties of the coating film are reduced instead of fast drying of the coating film. .

The second epoxy resin may have a hydroxyl value (OHv) of 100 to 200 mgKOH/g, or 130 to 180 mgKOH/g. When the hydroxyl value of the second epoxy resin is less than the above range, there is a problem that the drying rate of the coating film is slow because there are few reactive groups. Problems can arise.

In addition, the second epoxy resin may be in the form of an aqueous dispersion having a solid content (NV) of 45 to 60% by weight based on the total weight of the resin. If the solid content of the second epoxy resin is less than the above range, there is a problem that the viscosity is lowered and the anti-sagging property is lowered. can

The second epoxy resin may be included in an amount of 5 to 15% by weight, or 8 to 12% by weight based on the total weight of the epoxy resin composition. When the content of the second epoxy resin is less than the above range, as the pot life of the composition is too short, workability is poor due to insufficient work time, and when it exceeds the above range, pot life is long and drying is slow There may be a problem that the efficiency is lowered.

vinyl aromatic oligomers

The vinyl aromatic oligomer serves as an auxiliary resin of the epoxy paint composition to provide flexibility to the prepared coating film and improve initial water resistance. Specifically, the vinyl aromatic oligomer imparts flexibility to the prepared coating film by expressing the flexible properties of the resin itself in the coating film, and suppresses moisture penetration by expressing on the surface of the coating film on which the hydrophobic properties of the resin are formed. can improve

The vinyl aromatic oligomer means an aromatic oligomer including a vinyl group.

The vinyl aromatic oligomer may have a glass transition temperature (Tg) of -5 to 6 °C, or -3 to 4 °C. When the glass transition temperature of the vinyl aromatic oligomer is less than the above range, due to the characteristic that the drying of the resin itself is slowed, a problem of lowering initial water resistance and adhesion on the surface of the formed coating film may occur, and if it exceeds the above range, the drying of the resin is excessively accelerated, and by advancing the surface drying of the coating film, the smoothness (leveling) of the applied coating material is inhibited, thereby causing a problem in that the appearance of the coating film is poor.

In addition, the vinyl aromatic oligomer may have a weight average molecular weight (Mw) of 1,000 to 2,000 g/mol. When the weight average molecular weight of the vinyl aromatic oligomer is less than the above range, there is a problem in that the drying of the coating film is slow.

The vinyl aromatic oligomer may have a hydroxyl group content of 0.5 to 10.0 wt% or 1.0 to 8.0 wt% based on the solid content of the vinyl aromatic oligomer. When the hydroxyl group content of the vinyl aromatic oligomer is less than the above range, there is a problem in that the drying of the coating film is slow.

In addition, the vinyl aromatic oligomer may have a viscosity of 100 to 2,500 mPa·s or 300 to 2,000 mPa·s at 25°C. When the viscosity at 25° C. of the vinyl aromatic oligomer is less than the above range, there is a problem of poor compatibility in the paint.

The vinyl aromatic oligomer may be included in an amount of 0.5 to 5% by weight, or 0.5 to 2% by weight based on the total weight of the epoxy resin composition. When the content of the vinyl aromatic oligomer is less than the above range, impact resistance and water resistance of the prepared coating film are insufficient.

Amine-based curing agent

The amine-based curing agent reacts with the epoxy resin to cure the composition to form a coating film.

The amine-based curing agent may include a polyamide resin and an epoxy-modified amine-based compound. In this case, the polyamide resin serves to improve the rheology of the prepared coating film. In addition, the epoxy-modified amine-based compound serves to improve the quick-drying and quick-setting properties of the composition at room temperature.

In addition, the polyamide resin may be prepared by reacting a dimer acid with a polyamine-based compound.

In this case, the dimer acid may be used without any particular limitation as long as it can be generally used in the preparation of the polyamide resin, for example, adipic acid, suberic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2 -methyl terephthalic acid, 5-methylisophthalic acid, hexahydrophthalic anhydride (HHPA), naphthenic acid, methyltetrahydrophthalic anhydride, and the like.

In addition, the polyamine-based compound may include two or more amine groups in one molecule, and examples thereof include an aliphatic polyamine-based compound, an aromatic polyamine-based compound, and a heterocyclic polyamine-based compound.

The polyamide resin may have an active hydrogen equivalent weight (AHEW) of 100 to 180 g/eq, or 120 to 160 g/eq. When the active hydrogen equivalent of the polyamide resin is less than the above range, there is a problem in that the rust prevention and impact resistance of the prepared coating film is deteriorated due to insufficient curing degree of the coating film. Since the required amount of the amide resin increases, there may arise a problem that the amount of the curing agent used becomes too large.

In addition, the polyamide resin may have a weight average molecular weight (Mw) of 300 to 600 g/mol or 400 to 500 g/mol. When the weight average molecular weight of the polyamide resin is less than the above range, there is a problem that compatibility with the epoxy resin is lowered. can

The epoxy-modified amine-based compound may be prepared by reacting an epoxy compound and an amine compound.

In this case, the epoxy compound may be a mono epoxy compound or a polyvalent epoxy compound, for example, butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, para-tert-butyl mono epoxy compounds such as phenyl glycidyl ether, ethylene oxide and propylene oxide; And polyhydric epoxy compounds, such as a bisphenol-type epoxy resin, a novolak-type epoxy resin, an ether ester-type epoxy resin, and a glycidyl-type epoxy resin, are mentioned.

In addition, the amine compound is a compound containing at least one amino group, for example, methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, ethanolamine , propanolamine, cyclohexylamine, isophoronediamine, aniline, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dimethanolamine, diethanolamine, dipropanolamine and the like.

The epoxy-modified amine-based compound may have a smaller active hydrogen equivalent than the polyamide resin. As described above, by using two types of amine-based curing agents having different active hydrogen equivalents, it is possible to control drying and curing rates to secure an appropriate drying time for a coating film and a sufficient pot life, thereby improving workability.

Specifically, the epoxy-modified amine-based compound may have an active hydrogen equivalent weight (AHEW) of 80 to 160 g/eq, or 100 to 140 g/eq. When the active hydrogen equivalent of the epoxy-modified amine compound is less than the above range, there is a problem in that the rust prevention property of the prepared coating film is lowered due to insufficient curing of the coating film, and when it exceeds the above range, the epoxy for proper curing reaction with the epoxy resin Since the required amount of the modified amine-based compound is increased, the amount of the curing agent used is increased and the appearance characteristics of the prepared coating film may be deteriorated.

The amine-based curing agent may include a polyamide resin and an epoxy-modified amine-based compound in a mass ratio of 1:0.5 to 1:2, or a mass ratio of 1:0.7 to 1:1.5. When the mass ratio of the polyamide resin and the epoxy-modified amine-based compound is less than the above range, that is, when a small amount of the epoxy-modified amine-based compound is used based on the polyamide resin, there is a problem in that it is difficult to control the pot life and workability of the paint. In the case of excess, that is, when an excessive amount of the epoxy-modified amine-based compound is used based on the polyamide resin, a problem in that the prepared coating film has poor impact resistance and abrasion resistance may occur.

The amine-based curing agent may be included in an amount of 1 to 5% by weight, or 2 to 4% by weight based on the total weight of the epoxy resin composition. Specifically, the epoxy paint composition is based on the total weight of the epoxy resin composition, 0.5 to 3% by weight, or 1.5 to 2.5% by weight of the polyamide resin, and 0.5 to 3% by weight, or 1.5 to 2.5% by weight of the epoxy-modified amine It may contain a system compound.

When the content of the amine-based curing agent is less than the above range, there is a problem that non-curing occurs during the production of the coating film and thus the physical properties of the prepared coating film are generally insufficient. Long-term physical properties of the coated film, for example, deteriorated rust resistance may occur. In addition, when the content of the polyamide resin is less than the above range, there is a problem that the coating workability is poor and the weather resistance of the coating film is inferior. can occur When the content of the epoxy-modified amine-based compound is less than the above range, there is a problem of slow drying under winter conditions, and when it exceeds the above range, the long-term weather resistance of the prepared coating film may be deteriorated.

pigment

The epoxy paint composition may further include a pigment. In this case, the pigment serves to impart color to the coating film prepared from the composition.

The pigment may be, for example, a color pigment, an extender pigment, a rust preventive pigment, or a mixture thereof.

The color pigment serves to secure hiding power and impart color to the coating film. In this case, the color pigment may be a black pigment, a white pigment, a blue pigment, a red pigment, a yellow pigment, a violet pigment, or a mixture thereof. In this case, the black pigment may be used without any particular limitation as long as it is a commonly known black pigment, for example, carbon black, graphite, iron oxide, or a mixture thereof may be used. In addition, the white pigment may be used without any particular limitation as long as it is a commonly known white pigment, for example, titanium dioxide (TiO ₂ ) and the like may be used.

The extender pigment increases the strength of the prepared coating film and serves to control the appearance characteristics and rheology of the coating film. The extender pigment may be used without any particular limitation as long as it is a commonly known component, for example, talc, barium sulfate, calcium carbonate, calcium silicate, or a mixture thereof may be used.

The anti-rust pigment serves to improve the rust-preventive properties of the prepared coating film. The rust preventive pigment may be used without any particular limitation as long as it is a commonly known component, for example, zinc phosphate, zinc phosphate hydrate, aluminum phosphate, calcium hydrogen phosphate, zinc-aluminum phosphate, strontium-zinc phosphosilicate, calcium Phosphate, strontium phosphosilicate, calcium borosilicate, or mixtures thereof and the like may be used.

The pigment may be included in an amount of 20 to 70% by weight, or 30 to 50% by weight based on the total weight of the epoxy resin composition. Specifically, the composition may include 7 to 12% by weight of a color pigment, 2 to 8% by weight of a rust preventive pigment, and 10 to 50% by weight of an extender pigment, based on the total weight of the epoxy resin composition.

If the content of the pigment is less than the above range, long-term durability may be inferior and defects may occur in the appearance of the coating film, and if it exceeds the above range, coating workability may deteriorate. In addition, when the content of the colored pigment is less than the above range, there is a problem that the color of the prepared coating film is different from the target color. When the content of the rust preventive pigment is less than the above range, the rust preventive property of the prepared coating film is insufficient. When the content of the extender pigment is less than the above range, mechanical properties of the prepared coating film are insufficient.

solvent

The epoxy paint composition may further include a solvent. In this case, the solvent controls the viscosity of the coating composition to improve workability, control the drying rate, and control the content of volatile organic compounds (VOC).

The solvent may include water and an organic solvent compatible with water. In this case, the organic solvent compatible with water is, for example, alcohols and esters. Specifically, the organic solvent is n-propanol (n-Propanol), butoxy ethoxy ethanol (Butoxy ethoxy ethanol), diethylene glycol monobutyl ether (Diethylene glycol monobutyl ether), butoxy ethanol (Butoxy ethanol), ethylene glycol Ethylene glycol monobutyl ether, dipropylene glycol butyl ether (DPnB), ethylene glycol monohexyl ether, n-hexyl glycol, dipropylene glycol It may include at least one selected from the group consisting of n-butyl ether (Dipropylene glycol n-butyl ether), methoxy propanol (Methoxy propanol), and isopropyl alcohol (IPA).

In addition, the solvent may be included in an amount of 10 to 25% by weight, or 13 to 20% by weight based on the total weight of the epoxy resin composition. Specifically, the composition may include an organic solvent compatible with 9 to 20% by weight of water, and 1 to 5% by weight of water, based on the total weight of the epoxy resin composition.

When the solvent content is less than the above range, the viscosity of the composition is high and there is a problem of insufficient workability. When the content of water is less than the above range, there is a problem in that the coating workability of the paint is lowered and the appearance of the prepared film is not smooth. have. In addition, when the content of the organic solvent is less than the above range, there is a problem in that the appearance of the prepared coating film is deteriorated due to insufficient wetting property of the coating material. can

additive

The water-based epoxy paint composition may further include additives such as a dispersant, a surface adjuster, a pH adjuster, a thickener, an anti-foaming agent, and a rust preventive agent, and may further include additives that can be added to the water-based epoxy paint composition in general. At this time, each of the additives is not particularly limited as long as it can be used in a conventional aqueous epoxy paint composition.

The water-based epoxy paint composition according to the present invention as described above can be applied to yard (external) painting because it can be quickly dried and cured at room temperature, and has excellent workability due to an appropriate pot life, and has excellent storage stability. In addition, the coating film prepared from the epoxy paint composition has excellent mechanical properties such as adhesion, impact resistance, rust prevention and abrasion resistance.

Hereinafter, the present invention will be described in more detail through examples. However, these examples are only for helping the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

[Example]

Examples 1 to 22 and Comparative Examples 1 to 8. Epoxy paint composition

By mixing each component in the composition as described in Tables 1 to 4, an aqueous epoxy paint composition was prepared. In this case, IPA is isopropyl alcohol.

Ingredients (wt%) Example One 2 3 4 5 6 7 First Epoxy Resin-1 20 23 27 30 23 first epoxy resin-2 23 No. 1 Epoxy Resin-3 23 Second Epoxy Resin-1 12 10 10 8 10 10 Second Epoxy Resin-2 10 Second Epoxy Resin-3 Vinyl Aromatic Oligomer-1 2 One One 0.5 One One One Vinyl aromatic oligomer-2 Vinyl Aromatic Oligomer-3 Polyamide resin-1 2 2 2 2 2 2 2 Polyamide resin-2 Epoxy-modified amine compound-1 2 2 2 2 2 2 2 Epoxy-modified amine compound-2 TIO ₂ 12 12 10 10 12 12 12 barium sulfate 11.5 11.5 10 10 11.5 11.5 11.5 zinc phosphate 5.5 5.5 5 4.5 5.5 5.5 5.5 talc 12 12 12 12 12 12 12 water 13.5 13.5 13.5 13.5 13.5 13.5 13.5 IPA 3 3 3 3 3 3 3 dispersant 4.2 4.2 4.2 4.2 4.2 4.2 4.2 surface conditioning agent 0.3 0.3 0.3 0.3 0.3 0.3 0.3 total amount 100 100 100 100 100 100 100

Ingredients (wt%) Example 8 9 10 11 12 13 14 First Epoxy Resin-1 23 26 26 23 23 23 23 first epoxy resin-2 No. 1 Epoxy Resin-3 Second Epoxy Resin-1 10 10 10 10 10 10 Second Epoxy Resin-2 Second Epoxy Resin-3 10 Vinyl Aromatic Oligomer-1 One One One One One Vinyl aromatic oligomer-2 One Vinyl Aromatic Oligomer-3 One Polyamide resin-1 2 1.5 1.5 2 2.35 1.6 Polyamide resin-2 2 Epoxy-modified amine compound-1 2 1.5 1.5 2 1.65 2.4 Epoxy-modified amine compound-2 2 TIO ₂ 12 11 11 12 12 12 12 barium sulfate 11.5 11.5 11.5 11.5 11.5 11.5 11.5 zinc phosphate 5.5 5.5 5.5 5.5 5.5 5.5 5.5 talc 12 11 11 12 12 12 12 water 13.5 13.5 13.5 13.5 13.5 13.5 13.5 IPA 3 3 3 3 3 3 3 dispersant 4.2 4.2 4.2 4.2 4.2 4.2 4.2 surface conditioning agent 0.3 0.3 0.3 0.3 0.3 0.3 0.3 total amount 100 100 100 100 100 100 100

Ingredients (wt%) Example 15 16 17 18 19 20 21 22 First Epoxy Resin-1 23 23 23 23 23 23 23 No. 1 Epoxy Resin-4 23 Second Epoxy Resin-1 10 10 10 10 10 10 10 2nd Epoxy Resin-4 10 Vinyl Aromatic Oligomer-1 One One One One One One One Vinyl Aromatic Oligomer-4 One Polyamide resin-1 2 2 2 2 4 One Polyamide resin-3 2 Epoxy-modified amine compound-1 2 2 2 2 4 3 Epoxy-modified amine compound-3 2 TIO ₂ 12 12 12 12 12 12 12 12 barium sulfate 11.5 11.5 11.5 11.5 11.5 11.5 11.5 11.5 zinc phosphate 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 talc 12 12 12 12 12 12 12 12 water 13.5 13.5 13.5 13.5 13.5 13.5 13.5 13.5 IPA 3 3 3 3 3 3 3 3 dispersant 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 surface conditioning agent 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 total amount 100 100 100 100 100 100 100 100

Ingredients (wt%) comparative example One 2 3 4 5 6 7 8 First Epoxy Resin-1 33 24 23 23 23 First Epoxy Resin-5 23 No. 1 Epoxy Resin-6 23 Second Epoxy Resin-1 33 10 10 10 Second Epoxy Resin-5 10 Second Epoxy Resin-6 10 3rd Epoxy Resin 10 Vinyl Aromatic Oligomer-1 One One One One One One One Polyamide resin-1 2 2 2 2 2 2 2 2 Epoxy-modified amine compound-1 2 2 2 2 2 2 2 2 TIO ₂ 12 12 12 12 12 12 12 12 barium sulfate 11.5 11.5 11.5 11.5 11.5 11.5 11.5 11.5 zinc phosphate 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 talc 12 12 12 12 12 12 12 12 water 13.5 13.5 13.5 13.5 13.5 13.5 13.5 13.5 IPA 3 3 3 3 3 3 3 3 dispersant 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 surface conditioning agent 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 total amount 100 100 100 100 100 100 100 100

Manufacturers, product names, physical properties, etc. of each component used in Comparative Examples and Examples are shown in Table 5 below.

Ingredients (parts by weight) Properties Manufacturer and product name, or compound name First Epoxy Resin-1 NV: 57% by weight, EEW: 1,000 g/eq, Tg: 30°C Bisphenol A type epoxy resin first epoxy resin-2 NV: 55% by weight, EEW: 900 g/eq, Tg: 20°C Bisphenol A type epoxy resin No. 1 Epoxy Resin-3 NV: 58 wt%, EEW: 1,100 g/eq, Tg: 40°C Bisphenol A type epoxy resin No. 1 Epoxy Resin-4 NV: 56 wt%, EEW: 1,300 g/eq, Tg: 35 °C Bisphenol A type epoxy resin First Epoxy Resin-5 NV: 56 wt%, EEW: 950 g/eq, Tg: 5°C Bisphenol A type epoxy resin No. 1 Epoxy Resin-6 NV: 55% by weight, EEW: 1,000 g/eq, Tg: 55°C Bisphenol A type epoxy resin Second Epoxy Resin-1 NV: 53 wt%, EEW: 1,000 g/eq, Tg: -3°C, OHv: 150 mgKOH/g Polypropylene glycol modified epoxy resin Second Epoxy Resin -2 NV: 55% by weight, EEW: 850 g/eq, Tg: -5°C, OHv: 180 mgKOH/g Polypropylene glycol modified epoxy resin Second Epoxy Resin-3 NV: 50% by weight, EEW: 1,150 g/eq, Tg: -1°C, OHv: 130 mgKOH/g Polypropylene glycol modified epoxy resin 2nd Epoxy Resin-4 NV: 52 wt%, EEW: 700 g/eq, Tg: -3.5°C, OHv: 155 mgKOH/g Polypropylene glycol modified epoxy resin Second Epoxy Resin-5 NV: 50% by weight, EEW: 1,000 g/eq, Tg: -15°C, OHv: 110 mgKOH/g Polypropylene glycol modified epoxy resin Second Epoxy Resin-6 NV: 55% by weight, EEW: 1,000 g/eq, Tg: 5°C, OHv: 170 mgKOH/g Polypropylene glycol modified epoxy resin 3rd Epoxy Resin NV: 51% by weight, EEW: 1,100 g/eq, Tg: -5°C Isocyanate-modified epoxy resin Vinyl Aromatic Oligomer-1 Mw: 1,500 g/mol, Tg 1°C hydroxyl content of 5% by weight, viscosity at 25°C: 800 mPa·s, - Vinyl aromatic oligomer-2 Mw: 1,100 g/mol, Tg -4 °C hydroxyl content of 2% by weight, viscosity at 25 °C: 1,900 mPa s - Vinyl Aromatic Oligomer-3 Mw: 1,900 g/mol, Tg 5°C hydroxyl content of 8 wt%, viscosity at 25°C: 300 mPa·s - Vinyl Aromatic Oligomer-4 Mw: 1,650 g/mol, Tg -15°C hydroxyl content of 5% by weight, viscosity at 25°C: 500 mPa·s - Polyamide resin-1 NV: 87 wt%, AHEW: 150 g/eq, Mw: 430 g/mol - Polyamide resin-2 NV: 85 wt%, AHEW: 120 g/eq, Mw: 480 g/mol - Polyamide resin-3 NV: 88 wt%, AHEW: 80 g/eq, Mw: 450 g/mol - Epoxy-modified amine compound-1 NV: 87 wt%, AHEW: 120 g/eq - Epoxy-modified amine compound-2 NV: 87 wt%, AHEW: 100 g/eq - Epoxy-modified amine compound-3 NV: 87 wt%, AHEW: 200 g/eq - talc importance; 2.75, particle size (D50): 5.7㎛, pH: 8~9, moisture: 0.3% by weight or less - dispersant - Manufacturer: Coatex,
Product Name: Coadis 615 surface conditioning agent - Manufacturer: CHEM (YUEYANG),
Product Name: Greesol DFS

Test Example: Physical property evaluation

The aqueous epoxy paint compositions of Examples and Comparative Examples were coated to a dry film thickness of 45 μm, and left at room temperature for 60 minutes to form a coating film. Thereafter, the physical properties of the aqueous epoxy paint compositions and the prepared coating films of Examples and Comparative Examples were measured in the following manner, and the results are shown in Tables 7 to 10.

(1) storage stability

After the coating composition was left at 60° C. for 120 hours, the coating composition was visually evaluated for thickening, pigment precipitation, and phase separation.

Specifically, after storage, there is an increase in the viscosity of the paint, no pigment deposition and phase separation, excellent (◎), a soft precipitation, good (○), when there is a precipitation at a level that is easy to remix, soft precipitation and some phase separation. If there is, it was evaluated as normal (Δ), and if sedimentation at a level difficult to remix, which is a hard precipitation, occurred, it was evaluated as bad (×).

(2) drying time (hr)

The epoxy paint composition was coated to have a dry film thickness of 45 μm, and the drying time was measured according to ASTM D1640 while drying at 25° C. or 10° C.

(3) Pot life (hr)

After mixing the epoxy paint composition, the change in viscosity of the mixed paint is measured over time while standing at 40°C, and the time it takes for the change in viscosity (based on Zahn cup #3) to exceed 10% of the initial viscosity was done with

(4) Initial water resistance

According to the CCIA (China container industry association) water-based coating specification, the epoxy paint composition is coated with the air spray method on the steel specimen pretreated with surface blasting (SA 2.5), and then at room temperature (25°C) and low temperature (5°C) conditions. Drying was carried out for 1 day. The dried specimen was immersed in a fresh water tank until discrimination was ensured (at least 1 week), and the level of rust (ASTM D610) and blister (ASTM D714) generation on the surface of the coating film was evaluated.

(5) Initial adhesion

According to ASTM D3359 tape adhesion test method, after forming 25 squares of 2mmX2mm (width X length) with a knife on the coating film of the specimen, test the adhesiveness of the tape on the squares, and measure the degree of peeling to determine the degree of adhesion was evaluated.

At this time, 5B if 25 squares are 100% completely attached, 4B if the remaining squares are 95% or more and less than 100%, 3B if 85% or more and less than 95%, 2B if 65% or more and less than 85%, 35% or more and less than 65% Case 1B and less than 35% were evaluated as 0B.

(6) Initial impact resistance

In accordance with ASTM D2794, a weight of 60 lbs, 40 lbs, or 10 lbs was dropped on the front surface of the specimen (the surface coated with epoxy paint), and the surface of the specimen was observed to evaluate the initial front impact resistance. At this time, the weight of the weight at which cracks do not occur on the surface of the specimen was taken as the initial front impact resistance.

In addition, according to ASTM D2794, after dropping a 500 g weight from a height of 10 inches or more on the back side of the specimen (the side on which the epoxy paint composition is not applied), observe the surface of the coating film to ensure uniformity and peeling does not occur in the coating film. The maximum height was measured and it was set as the initial back impact resistance. It was evaluated that the higher the height, the better the physical properties.

(7) Anti-sagging

Immediately after applying the paint composition to a steel specimen by the airless spray method, the applied paint is scraped in the horizontal direction to form a boundary line, and then the specimen is left at room temperature (25°C) in the vertical direction to the ground to the extent that the paint flows down from the boundary line was understood.

Specifically, if there is no flow of paint, it is grade 1, if the boundary area is waving, it is grade 2, if there is some flow of paint (slight sagging), it is grade 3, if there is a lot of flow (severe sagging), it is grade 4 , If the flow of the paint was very severe and the boundary line was completely overlapped (Collapsed), it was evaluated as a grade of 5.

(8) Appearance characteristics

After the coating composition was coated according to the CCIA (China container industry association) water-based coating specification, the appearance level of the surface of the coating film formed by drying under conditions similar to that of an actual coating line was evaluated.

The main evaluation items are pinholes exposed on the surface of the coating film, de-wetting caused by insufficient wetting of the substrate, and inner pinholes hidden in the coating film. was observed by cutting in the diagonal direction. In general, using a magnifying glass of 15 times or more, visual determination is made by the size and frequency of defects in the coating film, and the specific determination criteria are as shown in Table 6.

(9) occurrence of rust: anti-rust 1

Based on ASTM D610, the numerical value of the overall occurrence level (%) such as the size and frequency of rust occurrence was measured with the naked eye, and the rust prevention property was evaluated based on ASTM D610.

(10) Generation of bilster: Anti-rust-2

Based on ASTM D714, the numerical value obtained by observing the size and frequency of blistering with the naked eye was evaluated as rust prevention based on ASTM D714.

(11) Rust creep occurrence: Anti-rust-3

In accordance with ASTM D1654, a 1 mm-wide sheath was drawn with a blade to a length of 2 inches in the horizontal direction and 3 inches in the vertical direction on the coated specimen according to ASTM D1654. (condensing moisture for 4 hours in an oven) was repeated for 3 days, followed by an accelerated corrosion cycle (a solution of 0.35 wt% ammonium chloride and 0.05 wt% sodium chloride dissolved in deionized water at 30°C with a pH of 5.0 to 5.4 for 4 hours) After spraying and condensing moisture for 2 hours at 40°C) for 4 days, a total of 8 times (8 weeks) were treated once, and the average value measured at intervals of 1 cm in the distance (mm) from which the rust penetrated from the sheath was evaluated for rust prevention. It was evaluated that the lower the numerical value, the better the physical properties.

(12) Adhesiveness

After exposing the specimen coating film for 8 weeks (1,344 hours) according to the same test cycle as in item (11), adhesion was evaluated in the same manner as in item (5).

(13) Impact resistance

After exposing the specimen coating film for 8 weeks (1,344 hours) according to the same test cycle as in item (11), impact resistance was evaluated in the same manner as in item (6).

(14) wear resistance

Abrasion resistance was evaluated by measuring the degree of abrasion (mg) using an abrasion tester (Taber's 5155 abraser, CS-17 abrading wheel applied) in accordance with ASTM D4060. It was evaluated that the lower the numerical value, the better the physical properties.

As can be seen from Tables 7 to 10, when the coating compositions of Examples 1 to 22 according to the present invention were applied, the physical properties were generally excellent.

On the other hand, when the coating compositions of Comparative Examples 1 to 8, which deviates from the composition according to the present invention, were applied, overall physical properties were inferior to those of the coatings of Examples.

Specifically, in Comparative Example 1 to which the first epoxy resin was not applied, the drying time and the pot life were long, and the appearance characteristics were inferior. In addition, in Comparative Example 2 to which the second epoxy resin was not applied, the drying time and pot life were short and storage stability was inferior, and in Comparative Example 3 to which the vinyl aromatic oligomer was not applied, initial water resistance and impact resistance were inferior. Furthermore, in the case of Comparative Example 4 to which the first epoxy resin-5 having a glass transition temperature of less than 10° C. is applied, the drying time is long and the workability is poor, and the first epoxy resin-6 having a glass transition temperature of more than 50° C. is applied. 5 was inferior in appearance characteristics. In addition, in the case of Comparative Example 6 to which the second epoxy resin-5 having a glass transition temperature of less than -10°C was applied, the pot life was long and workability was insufficient, and the second epoxy resin-6 having a glass transition temperature exceeding -1°C was applied. Comparative Example 7 had inferior anti-sagging properties. Furthermore, Comparative Example 8, in which an isocyanate-modified epoxy resin was applied instead of a polyalkylene glycol-modified epoxy resin as the second epoxy resin, did not have good compatibility with the bisphenol A-type epoxy resin, so the physical properties were generally inferior.

Claims (5)

A first epoxy resin, a second epoxy resin, including a vinyl aromatic oligomer and an amine-based curing agent,
The first epoxy resin has a glass transition temperature of 20 to 40 ℃,
The second epoxy resin is an aqueous epoxy paint composition comprising a polyalkylene glycol-modified epoxy resin having a glass transition temperature of -10 to -1 °C. The method according to claim 1,
The first epoxy resin comprises a bisphenol A-type epoxy resin having an epoxy equivalent of 800 to 1,200 g/eq,
The second epoxy resin has an epoxy equivalent of 850 to 1,250 g/eq, an aqueous epoxy paint composition. The method according to claim 1,
The vinyl aromatic oligomer has a glass transition temperature of -5 to 6 °C and a weight average molecular weight of 1,000 to 2,000 g/mol, an aqueous epoxy paint composition. The method according to claim 1,
The amine-based curing agent comprises a polyamide resin and an epoxy-modified amine-based compound, the aqueous epoxy paint composition. The method according to claim 1,
15 to 35% by weight of the first epoxy resin, 5 to 15% by weight of the second epoxy resin, 0.5 to 5% by weight of a vinyl aromatic oligomer and 1 to 5% by weight of an amine-based curing agent, an aqueous epoxy paint composition comprising a curing agent.