KR20240020887A - Epoxy coating composition - Google Patents

Abstract

The present invention relates to an epoxy paint composition having excellent physical properties under various curing conditions.

Description

Epoxy coating composition {EPOXY COATING COMPOSITION}

The present invention relates to an epoxy paint composition having excellent physical properties under various curing conditions.

Steel pipes for gas are painted with various paints to protect their interior during storage, construction, and gas transportation. Depending on the purpose of the steel pipe, epoxy paints or powder coatings with various physical properties are being proposed. For example, registered patent No. 2118945 discloses an epoxy resin paint for steel pipes containing BPA type epoxy resin, BPF type epoxy resin, isocyanate prepolymer, color pigment, extender pigment, zirconium powder, sericite powder, and solvent in a specific mixing ratio, there is.

These solvent-based epoxy paints generate a lot of volatile organic compounds (VOC), and recently, demand for high-solids solvent-based epoxy paints or water-soluble epoxy paints has been increasing to reduce environmental pollution. However, high-solids solvent-based epoxy paints or water-soluble epoxy paints still have limitations in that it is difficult to secure physical properties that can replace conventional solvent-based epoxy paints.

In addition, the development of solvent-free epoxy paints is in progress as an alternative to solvent-based epoxy paints, but conventional solvent-free paints have not been able to sufficiently secure the physical properties required for paints, such as flexibility, hardness, water resistance, and rust prevention. In particular, conventional solvent-free paints exhibit certain physical properties only under limited curing conditions, so the development of paints with excellent physical properties under various curing conditions is required.

The present invention provides an epoxy coating composition having excellent physical properties over a wide range of curing temperature conditions.

The present invention relates to a subject matter comprising epoxy resin, reactive diluent, extender pigment and silicone resin; and a solvent-free two-component epoxy paint composition comprising a curing agent containing an amine, an amide resin, and a non-reactive diluent.

The present invention provides a solvent-free, two-component epoxy paint composition that has excellent physical properties over a wide range of curing temperature conditions. The coating composition of the present invention is a solvent-free type that is environmentally friendly and provides a coating film with excellent flexibility, hardness, water resistance, and rust prevention. The epoxy paint composition of the present invention can be applied as a paint for gas steel pipes.

Hereinafter, the present invention will be described in detail. However, it is not limited to the following content, and each component may be variously modified or selectively mixed as needed. Accordingly, it should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

“Viscosity” as used herein is measured by a common method known in the art, and can be measured, for example, using a Brookfield viscometer at room temperature (25°C). “Particle size (D50)” is measured by a common method known in the art and can be measured, for example, with a laser particle size analyzer. “Weight average molecular weight” is measured by a common method known in the art, and can be measured, for example, by a GPC (gel permeation chromatograph) method.

The solvent-free two-component epoxy paint composition of the present invention includes a base material including an epoxy resin, a reactive diluent, an extender pigment, and a silicone resin; and curing agents including amines, amide resins, and non-reactive diluents. The epoxy paint composition of the present invention may further include additives such as anti-settling agents, matting agents, anti-filming agents, dispersants, waterproofing agents, leveling agents, drying accelerators, anti-foaming agents, antibacterial agents, water repellent agents, and anti-wetting agents, if necessary.

<topic>

epoxy resin

The main ingredient of the epoxy coating composition of the present invention includes an epoxy resin. The epoxy resin may include a first epoxy resin containing a Bisphenol-A Epoxy resin and a second epoxy resin containing a Phenol Novolac Epoxy resin. When the first epoxy resin and the second epoxy resin are mixed and used, the bending resistance and water resistance of the coating film can be further improved.

The first epoxy resin may have a viscosity (25°C) of 10,000 to 15,000 cPs, for example, 11,500 to 13,500 cPs, and an epoxy equivalent weight of 150 to 220 g/eq, for example, 184 to 194 g/eq. If the viscosity (25°C) of the first epoxy resin is less than the above-mentioned range, the physical properties may be deteriorated because the viscosity is lowered, and if it is greater than the above-mentioned range, the viscosity may be increased and workability may be deteriorated. If the epoxy equivalent weight of the first epoxy resin is outside the above-mentioned range, the physical properties of the coating film may deteriorate.

The first epoxy resin may be included in an amount of 30 to 50% by weight, for example, 35 to 45% by weight, based on the total amount of the subject matter. If the content of the first epoxy resin is less than the above-mentioned range, bending resistance may be inferior, and if it exceeds the above-mentioned range, solvent resistance may be inferior.

The second epoxy resin may have a viscosity (25°C) of 15,000 to 35,000 cps, for example, 20,000 to 30,000 cps, and an epoxy equivalent weight of 130 to 220 g/eq, for example, 155 to 195 g/eq. If the epoxy equivalent weight of the second epoxy resin is less than the above-mentioned range, solvent resistance may be reduced, and if it exceeds the above-mentioned range, flexibility may be reduced.

The second epoxy resin may be included in an amount of 1 to 25% by weight, for example, 5 to 20% by weight, based on the total amount of the subject matter. If the content of the second epoxy resin is less than the above-mentioned range, solvent resistance may be inferior, and if it exceeds the above-mentioned range, bending resistance may be inferior.

reactive diluent

The subject matter of the epoxy coating composition of the present invention includes a reactive diluent. As the reactive diluent, a difunctional diglycidyl ether type reactive diluent may be used. Bifunctional diglycidyl ethers include 1,4-Butanediol diglycidyl ether, Neopentyl Glycol Diglycidyl Ethers, and 1,6-hexanediol. Diglycidyl ether (1.6-Hexanediol Diglycidyl Ether), etc. may be used. The bifunctional diglycidyl ether may be used alone or in combination of two or more types.

The reactive diluent may have a viscosity (25°C) of 10 to 20 cps and an epoxy equivalent weight of 100 to 150 g/eq.

The reactive diluent may be included in an amount of 2 to 15% by weight, for example, 2 to 8% by weight, based on the total amount of the subject matter. If the content of the reactive diluent is less than the above-mentioned range, the viscosity may increase and workability may deteriorate, and if it exceeds the above-mentioned range, the viscosity may decrease and workability may improve, but the physical properties of the coating film may deteriorate.

constitution pigment

The subject matter of the epoxy paint composition of the present invention includes an extender pigment. Extending pigments play a role in improving the physical properties of the paint film. Silica, talc, calcium carbonate, magnesium carbonate, barium sulfate, etc. can be used as the extender pigment. The extender pigments can be used alone or in combination of two or more.

The constitution pigment may be included in an amount of 20 to 50% by weight, for example, 30 to 45% by weight, based on the total amount of the subject matter. When the content of the extender pigment is within the above-mentioned range, the mechanical properties of the coating film can be improved.

silicone resin

The main ingredient of the epoxy coating composition of the present invention includes a silicone resin. Silicone resin plays a role in improving the flexibility of the coating film. Polysiloxane, etc. can be used as the silicone resin, and for example, methylsilsesquioxane can be used. The silicone resin has a hollow structure and improves flexibility and adhesion by crosslinking with the epoxy resin to form pores in the paint.

The solid content of the silicone resin is 90 to 100%, the average particle size (D50) is 2 to 12 ㎛, for example 4 to 8 ㎛, the flash point is 100 to 200 ℃, eg 120 to 150 ℃, and the weight The average molecular weight may be 500 to 700 g/mol, for example 550 to 650 g/mol. If the average particle size of the silicone resin is less than the above-mentioned range, the effect of the silicone is insufficient and the viscosity is lowered, which may reduce workability and flexibility, and if it exceeds it, the paint becomes too bulky, which increases the viscosity of the paint and makes it hard (brittle). ) The properties may become stronger and the flexibility and workability may be reduced. If the flash point is below the above-mentioned range, the soft nature may become stronger and the adhesive strength may be reduced, and if it exceeds the above-mentioned range, the hard nature may become stronger and the flexibility may be reduced. .

The silicone resin may be included in an amount of 0.1 to 3% by weight, for example, 0.1 to 1% by weight, based on the total amount of the subject matter. If the content of the silicone resin is less than the above-mentioned range, the effect of silicone may be reduced and flexibility may be reduced, and if it is more than the above-mentioned range, workability may be reduced.

The epoxy resin and the silicone resin may be applied at a mixing ratio (weight ratio) of 1:0.1 to 2, for example, 0.5 to 1. If the mixing ratio of the silicone resin to the epoxy resin is less than the above-mentioned range, the effect of the silicone may be insufficient and flexibility may be reduced, and if it is greater than the above-mentioned range, the brittle nature may become strong and flexibility and workability may be reduced. there is.

<Hardener>

amine

The curing agent of the epoxy coating composition of the present invention includes an amine. The amine may include polyoxypropylene diamine, modified aliphatic amine, modified alicyclic amine, etc. The above amines may be used alone or in combination of two or more types. For example, the amine includes polyoxypropylene diamine, modified aliphatic amine, and modified alicyclic amine. When the above three types of amines are used together, the bending resistance, rust prevention, water resistance, and drying properties of the coating film can be further improved.

The active hydrogen equivalent of the polyoxypropylene diamine may be 40 to 80 g/eq, for example, 50 to 70 g/eq. If the active hydrogen equivalent of the polyoxypropylene diamine is outside the above-mentioned range, flexibility may be reduced.

The amine value of the modified aliphatic amine may be 300 to 450 mgKOH/g, for example, 360 to 420 mgKOH/g. For example, meta-xylene diamine can be used. If the amine value of the modified aliphatic amine is outside the above-mentioned range, the hardness of the coating film may decrease.

The amine value of the modified alicyclic amine may be 250 to 400 mgKOH/g, for example, 290 to 340 mgKOH/g. As an example, isophorone diamine can be used. If the amine value of the modified alicyclic amine is less than the above-mentioned range, drying properties may be reduced, and if it is greater than the above-mentioned range, flexibility may be reduced.

Based on the total amount of the curing agent, it may include 6 to 20% by weight of the polyoxypropylene diamine, 5 to 15% by weight of the modified aliphatic amine, and 35 to 50% by weight of the modified cycloaliphatic amine. If the content of polyoxypropylene diamine is less than the above-mentioned range, flexibility may be reduced, and if it is more than the above-mentioned range, rust prevention and solvent resistance may be reduced. If the content of the modified aliphatic amine is less than the above-mentioned range, the hardness of the coating film may decrease, and if it exceeds the above-mentioned range, flexibility may decrease. If the content of the modified alicyclic amine is less than the above-mentioned range, rust prevention and solvent resistance may be reduced, and if it is more than the above-mentioned range, flexibility may be reduced.

amide resin

The curing agent of the epoxy paint composition of the present invention includes an amide resin. Amide resin contains an acyl group in the resin structure and plays a role in improving the flexibility of the coating film.

The solid content of the amide resin is 90 to 100%, for example, 95 to 100%, the viscosity (25° C.) is 300 to 700 cPS, for example, 400 to 600 cPS, and the active hydrogen equivalent is 75 to 105 g/eq. , for example, 85 to 95 g/eq, and the amine number may be 300 to 600 mgKOH/g, for example, 400 to 500 mgKOH/g. If the solid content of the amide resin is below the above-mentioned range, mechanical properties may be reduced, and if the viscosity is outside the above-mentioned range, workability may be reduced. If the active hydrogen equivalent of the amide resin is outside the above-mentioned range, water resistance and rust prevention may be reduced, and if the amine value is outside the above-mentioned range, the flexibility of the coating film may be reduced.

As the amide resin, tetraethylenepentamine (TEPA) amide resin, triethylenetetramine (TETA) amide resin, etc. can be used.

The amide resin may be included in an amount of 3 to 20% by weight, for example, 5 to 15% by weight, based on the total amount of the curing agent. If the content of the amide resin is less than the above-mentioned range, flexibility may be reduced, and if it is more than the above-mentioned range, water resistance and rust prevention may be reduced.

The amine and the amide resin may be applied at a mixing ratio (weight ratio) of 1:0.01 to 2, for example, 0.1 to 0.5. If the mixing ratio of the amide resin to the amine is less than the above-mentioned range, flexibility may be reduced, and if it is more than the above-mentioned range, water resistance and rust prevention may be reduced.

Non-reactive diluent

The curing agent of the epoxy coating composition of the present invention includes a non-reactive diluent. The non-reactive diluent serves to control the viscosity of the paint composition.

Benzyl alcohol, dodecylphenol, etc. can be used as the non-reactive diluent. The non-reactive diluent may be used alone or in combination of two or more types.

The non-reactive diluent may be included in an amount of 5 to 40% by weight, for example, 10 to 30% by weight, based on the total amount of the curing agent. If the content of the non-reactive diluent is less than the above-mentioned range, the viscosity may increase and workability may be reduced, and if it exceeds the above-mentioned range, the viscosity may be lowered and workability may be improved, but the physical properties of the coating film may be deteriorated.

The two-component epoxy paint composition of the present invention may include 20 to 50 parts by weight of the curing agent based on 100 parts by weight of the main agent.

The present invention will be described in more detail through examples below. However, the following examples are only intended to aid understanding of the present invention, and the scope of the present invention is not limited to the examples in any way.

[Experimental Example 1-13]

The base material and hardener were prepared according to the compositions shown in Tables 1 and 2 below, and the base material and hardener were mixed at a weight ratio of 2.9:1 to prepare the paint composition of each experimental example.

[subject]

Epoxy resin 1-1: BPA epoxy resin (viscosity (25°C) 12,000 cps, epoxy equivalent weight 190 g/eq)

Epoxy resin 1-2: BPA epoxy resin (viscosity (25°C) 13,000 cps, epoxy equivalent weight 185 g/eq)

Epoxy resin 1-3: BPA epoxy resin (viscosity (25°C) 11,000 cps, epoxy equivalent weight 230 g/eq)

Epoxy resin 1-4: Cycloaliphatic epoxy resin (viscosity (25°C) 12,000 cps, epoxy equivalent weight 200 g/eq)

Epoxy resin 2-1: Phenol novolak resin (viscosity (25°C) 22,000 cps, epoxy equivalent weight 160 g/eq)

Epoxy resin 2-2: Phenol novolac resin (viscosity (25°C) 27,000 cps, epoxy equivalent weight 190 g/eq)

Epoxy resin 2-3: Phenol novolak resin (viscosity (25°C) 25,000 cps, epoxy equivalent weight 250 g/eq)

Body Pigment: Silica

Silicone resin 1: Methylsilsesquioxane (average particle size (D50) 6 ㎛, solid content 100%, flash point 125 ℃, weight average molecular weight 600 g/mol)

Silicone resin 2: Methylsilsesquioxane (average particle size (D50) 8 ㎛, solid content 100%, flash point 140 ℃, weight average molecular weight 650 g/mol)

Silicone resin 3: Methylsilsesquioxane (average particle size (D50) 15 ㎛, solid content 100%, flash point 120°C, weight average molecular weight 400 g/mol)

Reactive diluent: 1,6-hexanediol diglycidyl ether

Anti-settling agent: Alkyl ammonium chloride salt

Leveling agent: propylene glycol methyl ether acetate

Antifoaming agent: 2,6-dimethyl-4-heptanone

[Hardener]

Polyoxypropylene diamine: activated hydrogen equivalent 60 g/eq

Modified aliphatic amine: metaxylenediamine (amine value 380 mgKOH/g)

Modified alicyclic amine: isophorone diamine (amine value 330 mgKOH/g)

Amide resin 1: Tetraethylenepentamine (TEPA) amide resin (solid content 100%, viscosity (25°C) 500 cps, active hydrogen equivalent 90 g/eq, amine value 450 mgKOH/g)

Amide resin 2: TEPA amide resin (solids 100%, viscosity (25°C) 500 cps, active hydrogen equivalent 85 g/eq, amine value 400 mgKOH/g)

Amide resin 3: TEPA amide resin (solids 100%, viscosity (25°C) 500 cps, active hydrogen equivalent 120 g/eq, amine value 290 mgKOH/g)

Amide resin 4: Triethylenetetramine (TETA) amide resin (solid content 100%, viscosity (25°C) 500 cps, active hydrogen equivalent 90 g/eq, amine value 450 mgKOH/g)

Non-reactive diluent: Benzyl alcohol

[Physical property evaluation]

The physical properties of the coating composition prepared according to each experimental example were measured according to the method below, and the results are shown in Tables 3 and 4 below.

flexibility

The paint composition of each experimental example was painted, cured, and dried at room temperature for 7 days. The painted part of each dried specimen was placed in the Conical Mandrel Bending Tester with the painted part facing upward and completely bent for 1 second. Then, using a magnifying glass, the maximum length of the cracked area was measured from the end of the specimen.

[Evaluation standard]

◎: 8 mm or less

○: More than 8 mm and less than or equal to 10 mm

△: More than 10 mm and less than 13 mm

X: greater than 13 mm

Hardness

The paint composition of each experimental example was painted, cured, and dried at room temperature for 7 days. The Buchholz hardness tester was placed on the surface of each dried specimen for 30 seconds, and the length of the pressed marks was measured using a magnifying glass. The length of the pressed mark was calculated as 100, and the hardness was evaluated according to the following criteria.

[Evaluation standard]

◎: 100 or more

○: 94 or more but less than 100

△: 66 or more but less than 94

X: less than 66

water resistance

The paint composition of each experimental example was painted, cured, and dried at room temperature for 7 days. Each dried specimen was immersed in water for 480 hours so that it was 2/3 submerged, and then the condition was observed with the naked eye to check whether blisters had occurred. Afterwards, adhesion was confirmed with a 2 mm Cross Cut and evaluated according to the standards in the table below.

[Evaluation standard]

◎: No blister, adhesion 0 to 1

○: No blister, adhesion 2

△: Blister occurrence or adhesion 3 to 5

X: Blister generation and adhesion 3 to 5

Rust prevention

The paint composition of each experimental example was painted, cured, and dried at room temperature (25°C) for 7 days. An X-shaped scribe line was formed to expose the steel specimen. After exposing the specimen under rust prevention test conditions (Salt Spray x 480 hours), the area where blister occurred was measured and the maximum length was confirmed. Afterwards, the scribe line of the specimen was attached with tape and the maximum length of the peeled area was measured.

[Evaluation standard]

◎: Blister less than 1 mm, peeling less than 2 mm

○: Blister 1 mm or more and 2 mm or less, peeling 2 mm or more and 3 mm or less.

△: Blister exceeds 2 mm or peeling exceeds 3 mm

X: Blister exceeds 2 mm and delamination exceeds 3 mm

As shown in Tables 3 and 4, the coating film formed using the epoxy paint composition of Experimental Examples 1-11 according to the present invention showed excellent physical properties in all measurement items under two curing conditions. On the other hand, the coating films formed using the epoxy paint compositions of Experimental Example 12, which used a silicone resin outside the scope of the present invention, and Experimental Example 13, which did not use a silicone resin, showed differences in physical properties depending on the curing conditions. In particular, the bendability was very poor under the curing condition of 150°C

Claims (8)

Subject matter including epoxy resins, reactive diluents, extender pigments and silicone resins; and a curing agent including amines, amide resins, and non-reactive diluents;
The silicone resin includes polysiloxane,
A solvent-free, two-component epoxy paint composition in which the silicone resin has an average particle size (D50) of 2 to 12 ㎛. The method of claim 1, wherein the epoxy resin includes a first epoxy resin containing a Bisphenol-A Epoxy resin and a second epoxy resin containing a Phenol Novolac Epoxy resin. do,
The viscosity (25°C) of the first epoxy resin is 10,000 to 15,000 cPs, and the epoxy equivalent is 150 to 220 g/eq,
The viscosity (25°C) of the second epoxy resin is 15,000 to 35,000 cps, and the epoxy equivalent weight is 130 to 220 g/eq,
A two-part epoxy paint composition comprising 30 to 50% by weight of the first epoxy resin and 1 to 25% by weight of the second epoxy resin, based on the total amount of the subject matter. The two-part epoxy coating composition according to claim 1, wherein the silicone resin has a solid content of 90 to 100%, a flash point of 100 to 200° C., and a weight average molecular weight of 500 to 700 g/mol. The method of claim 1, wherein the amine includes polyoxypropylene diamine, modified aliphatic amine, and modified cycloaliphatic amine,
The active hydrogen equivalent of the polyoxypropylene diamine is 40 to 80 g/eq,
The amine value of the modified aliphatic amine is 300 to 450 mgKOH/g,
The amine value of the modified alicyclic amine is 250 to 400 mgKOH/g,
A two-component epoxy paint composition comprising 6 to 20% by weight of the polyoxypropylene diamine, 5 to 15% by weight of the modified aliphatic amine, and 35 to 50% by weight of the modified cycloaliphatic amine, based on the total amount of curing agent. The method of claim 1, wherein the solid content of the amide resin is 90 to 100%, the viscosity (25° C.) is 300 to 700 cPS, the active hydrogen equivalent is 75 to 105 g/eq, and the amine value is 300 to 600 mgKOH/g. Phosphorus two-component epoxy paint composition. The method of claim 1, comprising 31 to 75% by weight of the epoxy resin, 2 to 15% by weight of the reactive diluent, 20 to 50% by weight of the extender pigment, and 0.1 to 3% by weight of the silicone resin, based on the total amount of the subject matter,
A two-component epoxy paint composition comprising 46 to 85% by weight of the amine, 3 to 20% by weight of the amide resin, and 5 to 40% by weight of a non-reactive diluent, based on the total amount of curing agent. The two-part epoxy coating composition according to claim 1, wherein the mixing ratio of the epoxy resin and the silicone resin is 1:0.1 to 2 by weight. The two-part epoxy paint composition according to claim 1, wherein the mixing ratio of the amine and the amide resin is 1:0.01 to 2 by weight.