KR102663849B1 - Zinc-free primer composition - Google Patents

Abstract

The present invention includes a bisphenol-based epoxy resin, a fatty acid-modified epoxy resin, a polyamide resin, and an extender pigment, wherein the extender pigment includes one or more selected from the group consisting of silica, barium sulfate, talc, calcium carbonate, and feldspar. It relates to a zinc-free primer composition.

Description

Zinc-free primer composition {ZINC-FREE PRIMER COMPOSITION}

The present invention relates to a primer composition that is eco-friendly because it does not contain zinc, and the manufactured coating film has excellent appearance properties, rust prevention, and adhesion.

Epoxy resin reacts easily with amines or acids to exhibit a strong cured structure. In particular, bisphenol-A epoxy resin is used as a raw material in various industrial fields due to its structure's chemical resistance, heat resistance, hardness, and flexibility. Specifically, in the paint field, epoxy resin is used as a main ingredient in heavy-duty anti-corrosion paints and plant paints, and when used with amine or amide curing agents, it exhibits excellent performance as a paint. In addition, heavy-duty anti-corrosion paints and plant paints generally contain heavy metal pigments such as zinc (Zn) and chromium (Cr) to improve the rust prevention properties of the coating film. For example, Korean Patent No. 1392471 (Patent Document 1) discloses a two-component primer paint composition containing a low-viscosity liquid modified bisphenol A-type epoxy resin, a high-viscosity liquid modified bisphenol A-type epoxy resin, and an amine curing agent. there is.

Meanwhile, due to the recent strengthening of environmental regulations in each country, the demand for eco-friendly paints that do not contain heavy metal pigments in paints is increasing. However, conventional paint compositions that do not contain heavy metal pigments have a limitation in that the produced coating film lacks rust prevention properties. In particular, conventional heavy-duty anti-corrosion and/or plant paints that do not contain heavy metal pigments are difficult to replace with epoxy-based zinc primer compositions containing epoxy resin and zinc because the rust prevention properties of the manufactured coating film are very poor.

Therefore, research and development is being conducted on a coating composition that is eco-friendly as it does not contain heavy metal pigments, has excellent rust prevention and adhesion of the manufactured coating film, and can replace the epoxy-based zinc primer composition containing epoxy resin and zinc. It is necessary.

Korean Patent No. 1392471 (Publication date: July 16, 2013)

Accordingly, the present invention provides a primer composition that is excellent in environmental friendliness because it does not contain heavy metal pigments, has excellent rust prevention and adhesion of the manufactured coating film, and can replace the epoxy-based zinc primer composition containing epoxy resin and zinc. do.

The present invention includes bisphenol-based epoxy resins, fatty acid-modified epoxy resins, polyamide resins, and extender pigments,

The extender pigment includes one or more selected from the group consisting of silica, barium sulfate, talc, calcium carbonate and feldspar, providing a zinc-free primer composition.

The zinc-free primer composition according to the present invention is excellent in environmental friendliness as it does not contain heavy metal pigments such as zinc (Zn) and chromium (Cr), and the manufactured coating film is excellent in rust prevention, appearance characteristics, and adhesion, making it suitable as a primer composition. Suitable.

Hereinafter, the present invention will be described in detail.

The “weight average molecular weight” used herein is measured by a common method known in the art, and can be measured, for example, by a GPC (gel permeation chromatograph) method.

In the present invention, the “glass transition temperature” of the resin is measured by a common method known in the art, and can be measured, for example, by differential scanning calorimetry (DSC).

In addition, equivalent weights such as “epoxy equivalent weight” and “active hydrogen equivalent weight” can be measured by methods well known in the art, and can represent values measured by, for example, titration.

The zinc-free primer composition according to the present invention includes bisphenol-based epoxy resin, fatty acid-modified epoxy resin, polyamide resin, and extender pigment, and can be applied to materials for non-ferrous metals.

If the primer composition contains a combination of a bisphenol-based epoxy resin and a fatty acid-modified epoxy resin as described above, the degree of cross-linking of the manufactured coating film is lowered to facilitate the penetration of new coating components into the existing old coating film during recoating, thereby improving adhesion between the upper and lower coats. It has excellent adhesion and rust prevention properties as the hydrophobic hydrocarbons are oriented to the surface of the paint film and the hydrophilic epoxy or hydroxyl groups are oriented to the surface of the paint base.

Bisphenol-based epoxy resin

Bisphenol-based epoxy resin serves to improve adhesion to the top coat.

Specifically, when the primer composition contains a bisphenol-based epoxy resin, the degree of cross-linking of the manufactured coating film is lowered to facilitate penetration of new coating film components into the existing coating film during recoating work, resulting in excellent adhesion between the upper and lower coats.

The bisphenol-based epoxy resin is not particularly limited as long as it is commonly used in paint or primer compositions, and for example, at least one selected from the group consisting of bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, and bisphenol S-type epoxy resin. , or it may be a bisphenol A type epoxy resin. Specifically, the bisphenol-based epoxy resin may be diglycidyl ether of bisphenol-A (DGEBA), which is produced by reacting diphenyl (bisphenol A) with epichlorohydrin.

Additionally, the bisphenol-based epoxy resin may have an epoxy equivalent weight (EEW) of 450 to 700 g/eq, or 550 to 670 g/eq. When the epoxy equivalent weight of the bisphenol-based epoxy resin is within the above range, the primer composition has excellent storage properties. In addition, if the epoxy equivalent weight of the bisphenol-based epoxy resin is less than the above range, the density of the coating film cured after painting is lowered, resulting in poor rust prevention of the produced coating film, and if it exceeds the above range, it is difficult to control the viscosity of the composition. Problems may arise where the adhesion of the manufactured coating film is poor.

The bisphenol-based epoxy resin may have a viscosity of 3,700 to 6,300 cps, or 4,500 to 5,500 cps at 25°C. When the viscosity of the bisphenol-based epoxy resin is within the above range, the primer composition has excellent storage properties. In addition, when the viscosity of the bisphenol-based epoxy resin at 25°C is less than the above range, the spray pattern and sagging properties of the primer composition are reduced, resulting in poor flowability, and when it exceeds the above range, the primer composition may not adhere to the coated object. Problems such as poor painting workability may occur due to reduced leveling properties, etc.

Additionally, the bisphenol-based epoxy resin may have a weight average molecular weight (Mw) of 1,400 to 3,100 g/mol, or 1,800 to 2,400 g/mol. When the weight average molecular weight of the bisphenol-based epoxy resin is within the above range, the primer composition has excellent storage properties. In addition, if the weight average molecular weight of the bisphenol-based epoxy resin is less than the above range, crystallization of the primer composition occurs, causing insufficient storage stability and poor abrasion resistance, and if it exceeds the above range, a drying delay phenomenon occurs and the primer composition The painting workability of the composition may become insufficient and durability may decrease.

The bisphenol-based epoxy resin may have a glass transition temperature (Tg) of 23 to 37°C, or 25 to 35°C. When the glass transition temperature of the bisphenol-based epoxy resin is within the above range, the produced coating film has excellent water resistance. In addition, if the glass transition temperature of the bisphenol-based epoxy resin is less than the above range, there is a problem that the impact resistance of the manufactured coating film is poor, and if it exceeds the above range, the hardness of the manufactured coating film is weak, which may cause a problem of insufficient wear resistance. .

Fatty acid modified epoxy resin

Fatty acid-modified epoxy resin plays a role in improving rust prevention with the top coat.

Specifically, when the primer composition contains the fatty acid-modified epoxy resin, the hydrophobic hydrocarbons are oriented to the surface of the paint film, and the hydrophilic epoxy groups or hydroxyl groups are oriented to the surface of the painted base, thereby providing excellent rust prevention.

The fatty acid-modified epoxy resin is an epoxy resin modified with a fatty acid. At this time, the epoxy resin is not particularly limited as long as it is commonly used in paint or primer compositions, for example, bisphenol-type epoxy resin, alicyclic epoxy resin, fat. Chain epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, diglycidyl ether of biphenol, diglycidyl ether of naphthalenediol, diglycidyl ether of phenols, alcohols diglycidyl etherified products, multifunctional epoxy resins, and heterocyclic-containing epoxy resins. Specifically, the epoxy resin of the fatty acid-modified epoxy resin may be at least one selected from the group consisting of a bisphenol A-type epoxy resin, a bisphenol F-type epoxy resin, and a bisphenol S-type epoxy resin, or a bisphenol A-type epoxy resin.

Additionally, the fatty acid may be a monovalent fatty acid, a polyvalent fatty acid, or a mixture thereof. For example, the fatty acids include benzoic acid, acrylic acid, methacrylic acid, soybean oil fatty acid, tall oil fatty acid, castor oil fatty acid, rice bran oil fatty acid, linseed oil fatty acid, coconut oil fatty acid, lauric acid, linoleic acid, linolenic acid, and oleic acid. Contains one or more selected from the group consisting of lagonic acid, abietic acid, phthalic anhydride, maleic anhydride, isophthalic acid, adipic acid, tetrahydrophthalic anhydride, terephthalic acid, azeleic acid, sebacic acid, fumaric acid, succinic acid, and citric acid. can do. Specifically, the fatty acid may be a mixture of monovalent fatty acids and polyhydric fatty acids. That is, the fatty acid-modified epoxy resin may be a resin obtained by modifying a bisphenol A-type epoxy resin with a mixture of monohydric fatty acid and polyhydric fatty acid. As described above, when it contains a resin modified with a mixture of monohydric fatty acids and polyhydric fatty acids, the recoatability of the primer composition can be further improved.

The fatty acid modified epoxy resin may have a fatty acid modification ratio of 10 to 40% by weight, or 10 to 30% by weight, based on the total solid content of the epoxy resin. If the fatty acid modification rate of the fatty acid-modified epoxy resin is less than the above range, there may be a problem of poor adhesion of the manufactured coating film, and if it exceeds the above range, a problem may occur in which physical properties such as water resistance and rust prevention of the manufactured coating film are deteriorated. there is.

Additionally, the fatty acid-modified epoxy resin may have an epoxy equivalent weight (EEW) of 550 to 800 g/eq, or 650 to 750 g/eq. When the epoxy equivalent weight of the fatty acid-modified epoxy resin is within the above range, the primer composition has excellent storage properties. In addition, if the epoxy equivalent weight of the fatty acid-modified epoxy resin is less than the above range, there may be a problem of poor salt water resistance of the produced coating film, and if it exceeds the above range, there may be a problem of poor adhesion of the prepared coating film.

The fatty acid modified epoxy resin may have a viscosity of 5,500 to 8,000 cps, or 6,500 to 7,500 cps at 25°C. When the viscosity of the fatty acid-modified epoxy resin is within the above range, the primer composition has excellent adhesion to non-ferrous metals. In addition, if the viscosity of the fatty acid-modified epoxy resin at 25°C is less than the above range, there may be a problem of poor flowability of the primer composition, and if it exceeds the above range, there may be a problem of poor painting workability of the primer composition. .

Additionally, the fatty acid modified epoxy resin may have a weight average molecular weight (Mw) of 1,500 to 4,000 g/mol, or 2,500 to 3,500 g/mol. When the weight average molecular weight of the fatty acid-modified epoxy resin is within the above range, the primer composition has excellent adhesion to non-ferrous metals. In addition, if the weight average molecular weight of the fatty acid-modified epoxy resin is less than the above range, crystallization of the primer composition occurs, leading to insufficient storage stability and reduced hardness, and if it exceeds the above range, a drying delay phenomenon occurs and the primer composition There is a problem that the painting workability of the composition is reduced and durability is poor.

The fatty acid-modified epoxy resin may have a glass transition temperature (Tg) of 25 to 50°C, or 30 to 40°C. When the glass transition temperature of the fatty acid-modified epoxy resin is within the above range, the produced coating film has excellent water resistance. In addition, if the glass transition temperature of the fatty acid-modified epoxy resin is less than the above range, there is a problem that the impact resistance of the manufactured coating film is poor, and if it exceeds the above range, the hardness of the manufactured coating film is weak, which may cause a problem of insufficient wear resistance. .

The fatty acid-modified epoxy resin may be included in the composition in an amount of 1 to 15 parts by weight, or 5 to 11 parts by weight, based on 100 parts by weight of the bisphenol-based epoxy resin. When the content of the fatty acid-modified epoxy resin is within the above range, adhesion to the base non-ferrous metal and the top coat film is improved. In addition, if the content of the fatty acid-modified epoxy resin is less than the above range, the adhesion to the base non-ferrous metal is insufficient and the crosslink density of the produced coating film is lowered, resulting in a decrease in physical properties such as water resistance of the coating film, and if it exceeds the above range, the manufactured coating film Problems may arise such as a decrease in rust prevention or insufficient painting workability of the primer composition.

polyamide resin

The polyamide resin serves to harden the composition by reacting with the epoxy resin.

The polyamide resin is not particularly limited as long as it is commonly used in paint or primer compositions, and may be, for example, an acrylic modified polyamide resin.

Additionally, the polyamide resin may have a weight average molecular weight (Mw) of 1,000 to 3,000 g/mol or 1,500 or 2,500 g/mol. When the weight average molecular weight of the polyamide resin is within the above range, the primer composition has excellent adhesion to non-ferrous metals. In addition, if the weight average molecular weight of the polyamide resin is less than the above range, crystallization occurs at low temperatures, resulting in insufficient storage stability of the primer composition and a decrease in hardness, and if it exceeds the above range, delayed drying occurs. As a result, the painting workability of the primer composition may decrease and water resistance may decrease.

The polyamide resin may have an active hydrogen equivalent weight (AHEW) of 700 to 1,000 g/eq or 750 to 900 g/eq. When the active hydrogen equivalent of the polyamide resin is within the above range, the primer composition has excellent storage properties. In addition, if the active hydrogen equivalent of the polyamide resin is less than the above range, a drying delay phenomenon may occur, which may lower the painting workability and durability of the primer composition, and if it exceeds the above range, the hardness of the coating film will be high, reducing the impact resistance. This can become inferior.

The polyamide resin may have an amine value (AmV) of 90 to 120 mgKOH/g, or 100 to 115 mgKOH/g. When the amine value of the polyamide resin is within the above range, the primer composition has excellent storage properties. In addition, if the active hydrogen equivalent of the polyamide resin is less than the above range, the wear resistance may be reduced, and if it is more than the above range, the salt water resistance may be inferior.

Additionally, the polyamide resin may have a viscosity of 5,000 to 9,000 cps, or 6,500 to 8,000 cps at 25°C. When the viscosity of the polyamide resin at 25°C is within the above range, the primer composition has excellent painting workability on non-ferrous metals. In addition, if the viscosity of the polyamide resin at 25°C is less than the above range, there may be a problem of poor flowability of the primer composition, and if it exceeds the above range, there may be a problem of poor painting workability of the primer composition.

The primer composition may include the total epoxy equivalent of the bisphenol-based epoxy resin and the fatty acid-modified epoxy resin and the active hydrogen equivalent of the polyamide resin in an equivalent ratio of 1:0.1 to 0.7, or 1:0.1 to 0.4. When the equivalence ratio is within the above range, there is an effect of improving adhesion to the base non-ferrous metal and the top coat. In addition, when the equivalence ratio is less than the above range, that is, when the active hydrogen equivalent of the polyamide resin is insufficient relative to the epoxy equivalent, the adhesion to the base non-ferrous metal is insufficient and the crosslink density of the manufactured coating film is lowered, leading to a decrease in the long-term physical properties of the coating film. , if it exceeds the above range, that is, if the active hydrogen equivalent of the polyamide resin is excessive relative to the epoxy equivalent, the flexibility of the manufactured coating film may be reduced or the painting workability of the primer composition may be insufficient.

constitution pigment

The extender pigment serves to improve the strength and provide rust prevention to the manufactured paint film.

At this time, the extender pigment includes one or more selected from the group consisting of silica, barium sulfate, talc, calcium carbonate, and feldspar. The primer composition according to the present invention is excellent in environmental friendliness because it does not contain heavy metal pigments such as zinc and chromium, and although it contains the above-described extender pigment instead of the heavy metal pigment, the produced coating film has excellent rust prevention properties, making it a primer for non-ferrous metals. It can be suitably used as.

Specifically, the extender pigment may include feldspar, talc, or silica. When feldspar, talc, or silica is used as an extender pigment, the barrier effect of the primer composition is increased, thereby improving the long-term physical properties of the paint film.

The extender pigment does not limit the preferred shape, for example, spherical; Irregular spheres such as oblate spheres and oblate spheres; cubic shapes such as cubes and rhombuses; plate shapes such as flat plates, concave plates, and convex plates; and irregular shapes.

The extender pigment may have an average diameter of 5 to 30 nm. If the average direct application of the extender pigment is less than the above range, there may be a problem of poor adhesion of the primer composition, and if it exceeds the above range, the problem of poor rust prevention of the manufactured coating film may occur.

Additionally, the extender pigment may be included in the composition in an amount of 20 to 40 parts by weight, or 26 to 37 parts by weight, based on 100 parts by weight of the bisphenol-based epoxy resin. When the content of the extender pigment is within the above range, the produced coating film has excellent rust prevention properties. In addition, if the content of the extender pigment is less than the above range, there is a problem of insufficient mechanical properties such as rust prevention of the coating film, and if it is more than the above range, the primer composition has insufficient painting workability and cannot be applied to conventional coating methods such as airless spraying. This difficult problem can arise.

The primer composition may further include a solvent.

solvent

The solvent improves painting workability by controlling the viscosity of the primer composition and controls the drying speed.

The solvent is not particularly limited as long as it is commonly used in paint or primer compositions, and may include, for example, one or more selected from the group consisting of aromatic, acetate-based, alcohol-based, and propionate-based solvents. Specifically, the solvent includes aromatic solvents such as toluene and xylene; 1-methoxy-2-propyl acetate, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl glutarate, methyl succinate, methyl adipate, dimethyl glutarate, dimethyl succinate, dimethyl adipate Acetate-based solvents such as pate, butyl carbitol acetate, butyl cellosolve acetate, propylene glycol methyl ether acetate (PMA), and trimethyl o-acetate; Alcohol-based solvents such as n-butanol, propanol, 1-methoxy-2-propanol, and 2-butoxyethanol; Ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, and methyl isobutyl ketone; and propionate-based solvents such as ethyl ethoxypropionate; It may include etc. Additionally, commercially available products of the aromatic solvent include Cocosol #100 and Cocosol #150.

Additionally, the solvent may be included in the composition in an amount of 7 to 25 parts by weight, or 12 to 20 parts by weight, based on 100 parts by weight of the bisphenol-based epoxy resin. When the solvent content in the primer composition is within the above range, the storage stability of the composition is improved. In addition, if the content of the solvent is less than the above range, the viscosity of the primer composition is high, resulting in insufficient painting workability, and if it exceeds the above range, the viscosity of the primer composition is low, resulting in insufficient painting workability, and the physical properties of the manufactured coating film are deteriorated. Problems may arise.

additive

The primer composition may further include additives such as a curing catalyst, anti-rust pigment, and anti-settling agent. At this time, the additive is not particularly limited as long as it is commonly used in primer compositions.

2-component type

The primer composition may be a two-component type consisting of a main part and a hardener part. For example, the primer composition may include a main portion including a bisphenol-based epoxy resin, a fatty acid-modified epoxy resin, and an extender pigment; And it may be a two-component type consisting of a curing agent containing a polyamide resin. At this time, each of the main part and the hardener part may further include additives typically used in primer compositions.

In addition, when the primer composition is a two-component type as described above, the main part and the hardener part can be stored in separate containers and mixed immediately before use.

The primer composition has a viscosity of 60 to 110 KU, or 80 to 100 KU at 25°C, and may contain 45 to 70% by weight, or 54 to 63% by weight of solid content based on the total weight of the composition. If the viscosity of the primer composition at 25°C is less than the above range, there may be a problem of poor flowability, and if it exceeds the above range, there may be a problem of poor painting workability. In addition, if the solid content of the primer composition is less than the above range, the viscosity is excessively low, making it difficult to secure the film thickness during painting, and there is a problem of insufficient painting workability due to a drop in viscosity, and if it exceeds the above range, the viscosity of the primer composition is low. This may cause problems such as deterioration in painting workability.

As described above, the primer composition according to the present invention is excellent in environmental friendliness because it does not contain heavy metal pigments such as zinc (Zn) and chromium (Cr), and the manufactured coating film has excellent rust prevention, appearance characteristics, and adhesion, making it a primer for non-ferrous metals. It is very suitable as a composition.

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

[Example]

Examples 1 to 22 and Comparative Examples 1 to 6. Preparation of primer composition

The main part and the hardener part were prepared by mixing each component in the composition as shown in Tables 1 to 4 below.

After placing the prepared main part in a container, the total epoxy equivalent of the bisphenol-based epoxy resin and the fatty acid-modified epoxy resin of the main part and the active hydrogen equivalent of the polyamide resin were added and stirred to prepare a primer composition.

Ingredients (parts by weight) Example One 2 3 4 5 6 7 Subject section Bisphenol-based epoxy resin-1 100 Bisphenol-based epoxy resin-2 100 Bisphenol-based epoxy resin-3 100 Bisphenol-based epoxy resin-4 100 Bisphenol-based epoxy resin-5 100 Bisphenol-based epoxy resin-6 100 Bisphenol-based epoxy resin-7 100 Fatty acid modified epoxy resin-1 7 7 7 7 7 7 7 Constitutional Pigment-1 32 32 32 32 32 32 32 xylene 17 17 17 17 17 17 17 Hardener part Polyamide Resin-1 100 100 100 100 100 100 100

Ingredients (parts by weight) Example 8 9 10 11 12 13 14 15 Subject section Bisphenol-based epoxy resin-1 100 100 100 100 100 100 100 100 Fatty acid modified epoxy resin-1 11 5 Fatty acid modified epoxy resin-2 7 Fatty acid modified epoxy resin-3 7 Fatty acid modified epoxy resin-4 7 Fatty acid modified epoxy resin-5 7 Fatty acid modified epoxy resin-6 7 Fatty acid modified epoxy resin-7 7 Constitutional Pigment-1 32 32 32 32 32 32 37 26 xylene 17 17 17 17 17 17 20 12 Hardener part Polyamide Resin-1 100 100 100 100 100 100 100 100

Ingredients (parts by weight) Example 16 17 18 19 20 21 22 Subject section Bisphenol-based epoxy resin-1 100 100 100 100 100 100 100 Fatty acid modified epoxy resin-1 7 7 7 7 7 7 7 Constitutional Pigment-1 32 32 32 32 Constitutional Pigment-2 32 Constitutional pigment-3 32 Constitutional pigment-4 32 xylene 17 17 17 17 17 17 17 Hardener part Polyamide Resin-1 100 100 100 Polyamide Resin-2 100 Polyamide Resin-3 100 Polyamide Resin-4 100 Polyamide Resin-5 100

Ingredients (parts by weight) Comparative example One 2 3 4 5 6 Subject section Bisphenol-based epoxy resin-1 100 100 100 Fatty acid modified epoxy resin-1 100 7 100 CTBN modified epoxy resin 7 100 cardinol epoxy resin 7 7 Constitutional Pigment-1 32 32 32 32 32 xylene 17 17 17 17 17 17 Hardener part Polyamide Resin-1 100 100 100 100 100 100

Hereinafter, the manufacturer and product name of each component used in the examples and comparative examples are shown in Table 5 below, where EEW is the epoxy equivalent, VIS is the viscosity, Mw is the weight average molecular weight, Tg is the glass transition temperature, and AHEW is the glass transition temperature. is the active hydrogen equivalent, and AmV is the amine value.

ingredient note Bisphenol-based epoxy resin-1 EEW 600 e/eq, VIS (25℃) 5,000cps, Mw 2,200g/mol, Tg 30℃ Bisphenol-based epoxy resin-2 EEW 670 e/eq, VIS (25℃) 5,200cps, Mw 2,100g/mol, Tg 33℃ Bisphenol-based epoxy resin-3 EEW 550 e/eq, VIS (25℃) 4,900cps, Mw 2,000g/mol, Tg 31℃ Bisphenol-based epoxy resin-4 EEW 580 e/eq, VIS (25℃) 5,000cps, Mw 2,000g/mol, Tg 35℃ Bisphenol-based epoxy resin-5 EEW 610 e/eq, VIS(25℃) 5,100cps, Mw 2,100g/mol, Tg 25℃ Bisphenol-based epoxy resin-6 EEW 750 e/eq, VIS (25℃) 6,500cps, Mw 3,300g/mol, Tg 42℃ Bisphenol-based epoxy resin-7 EEW 400 e/eq, VIS (25℃) 3,000cps, Mw 1,000g/mol, Tg 18℃ Fatty acid modified epoxy resin-1 Fatty acid denaturation rate 20% by weight, EEW 700 e/eq, VIS (25℃) 7,000cps, Mw 3,000g/mol, Tg 35℃ Fatty acid modified epoxy resin-2 Fatty acid denaturation rate 22% by weight, EEW 750 e/eq, VIS (25℃) 7,300cps, Mw 3,200g/mol, Tg 36℃ Fatty acid modified epoxy resin-3 Fatty acid denaturation rate 25% by weight, EEW 650 e/eq, VIS (25℃) 7,100cps, Mw 2,800g/mol, Tg 34℃ Fatty acid modified epoxy resin-4 Fatty acid denaturation rate 23% by weight, EEW 720 e/eq, VIS (25℃) 6,8000cps, Mw 3,000g/mol, Tg 40℃ Fatty acid modified epoxy resin-5 Fatty acid denaturation rate 20% by weight, EEW 710 e/eq, VIS (25℃) 7,000cps, Mw 3,300g/mol, Tg 30℃ Fatty acid modified epoxy resin-6 Fatty acid denaturation rate 25% by weight, EEW 850 e/eq, VIS (25℃) 8,500cps, Mw 4,500g/mol, Tg 55℃ Fatty acid modified epoxy resin-7 Fatty acid denaturation rate 22% by weight, EEW 500 e/eq, VIS (25℃) 1,000cps, Mw 1,000g/mol, Tg 20℃ CTBN modified epoxy resin Product Name: KR-170, Manufacturer: Kukdo Chemical cardinol epoxy resin Product Name: KF EPIOL-PE300, Manufacturer: Kukdo Chemical Constitutional Pigment-1 Feldspar, grain size 17 nm Constitutional Pigment-2 Feldspar, grain size 25 nm Constitutional pigment-3 Talc, particle size 20 nm Constitutional pigment-4 Silica, particle size 7 nm Polyamide Resin-1 Mw 2,000g/eq, AHEW 800g/eq, AmV 108mgKOH/g, Vis(25℃) 7,000cps Polyamide Resin-2 Mw 2,500g/eq, AHEW 820g/eq, AmV 105mgKOH/g, Vis(25℃) 7,200cps Polyamide Resin-3 Mw 1,500g/eq, AHEW 810g/eq, AmV 110mgKOH/g, Vis(25℃) 7,000cps Polyamide Resin-4 Mw 2,300g/eq, AHEW 900g/eq, AmV 115mgKOH/g, Vis(25℃) 7,100cps Polyamide Resin-5 Mw 2,300g/eq, AHEW 750g/eq, AmV 100mgKOH/g, Vis(25℃) 6,600cps

Test example: Evaluation of properties of manufactured coating film

Using an airless sprayer, set the nozzle diameter to 0.09 inches, spray pressure to 120 atm, and spray angle to 65 degrees, then use steel or HDG (Hot Dip Galvanized Steel) as the substrate and apply the compositions of Examples and Comparative Examples to the surface of the substrate. A paint film was prepared by painting to a dry film thickness of 175㎛. Afterwards, the physical properties of the coating film were measured in the following manner, and the results are shown in Tables 6 to 9.

(1) Blistering: Rust prevention

In accordance with ASTM D714, 5% salt water was sprayed on the coating film, left for 1,000 hours, and the exterior of the specimen was observed to determine whether blisters were present to evaluate rust prevention.

At this time, excellent (◎) if no blisters occurred, good (○) if blisters with a diameter of 1㎛ or less occurred, average (△) if blisters with a diameter of 5㎛ or less but more than 1㎛ occurred, and 5㎛ in diameter. If excessive blisters occurred, it was evaluated as poor (×).

(2) Crosscut: Adhesion-1

Based on the information described in ASTM D3359, adhesion was measured by drawing 100 squares (2 mm wide At this time, adhesion was evaluated according to the standards described in ISO 2409, and the number of peeled areas was expressed as a number, and the closer the value was to 0, the better the physical properties were evaluated.

(3) Dolly: Adhesion-2

Based on the contents described in ISO 4624, adhesion is evaluated by measuring the maximum vertical tension that the paint film can have before the dolly is separated after attaching a dolly to the paint film with an adhesion tester. did. The vertical tension force was expressed in numbers, and the larger the value, the better the physical properties.

(4) Accelerated cycling endurance test (Cycle aging)

The paint film was sequentially exposed to UV-A and salt spray for 72 hours, and then stored at -20°C for 24 hours, which was one cycle, and 10 cycles were repeated. Afterwards, the peeling distance of the scratched area was measured using the method described in ISO 12944, and accelerated cycling endurance testing (cycle aging) was evaluated based on ISO 12944. The peeling distance was expressed in numbers, and the value was small. It was evaluated that the physical properties were excellent.

(5) Salt Spray Resistance

Based on ISO 9227, the paint film was scratched and the test was conducted for a certain period of time in a salt spray chamber, and then the degree of rusting of the scratched and non-scratched areas was confirmed. Afterwards, the peeled distance from the scratched area was measured and evaluated based on ISO 9227. The peeled distance was expressed in numbers, and the smaller the value, the better the physical properties. At this time, the conditions of the salt spray chamber are as follows.

1) Spray 5% by volume NaCl aqueous solution

2) Temperature in chamber: approximately 35℃, relative humidity: 95~98%

( 6) Sea Water Immersion

Based on ISO 4628, scratches were made on the paint film, and after a test was conducted for a certain period of time in a sea water chamber, the degree of rusting of the scratched and non-scratched areas was confirmed. After measuring the peeling distance from the scratched area, it was evaluated based on ISO 4628, and the peeling distance was expressed as a number. The smaller the value, the better the physical properties.

(7) Paintability

Primer samples by production date and storage temperature were painted using an airless sprayer and paint workability (dust generation pattern) was evaluated. The lower the dust generation, the better the workability, and the conditions of the painting equipment during painting work are as follows.

Discharge pressure: 4bar±1bar

Nozzle diameter: 0.028 inches ±3 inches

Spray angle: 60°±10°

(8) Hardness

Hardness was measured using a pencil on fully cured test specimens based on the information described in ASTM D3353. The higher the hardness of the pencil, the better the physical properties were evaluated.

(9) Impact resistance

Based on the information described in ASTM D2794, the test specimen was painted and subjected to impact at room temperature (20℃) at 120 lb·in to evaluate the distance (mm) of the peeling area of the coating film. The peeling area was expressed in numbers, and the value was The smaller the value, the better the physical properties were evaluated.

(10) Wear resistance

Based on the information described in ASTM D4060, the amount of wear was measured on the coating film after 1000 cycles using an abrasion tester (Taber Abraser, CS17 Wheel 1000g).

Measure the wear amount (ΔG) of the coating film, and if ΔG is between 100 and less than 105, it is excellent (◎), if it is between 105 and less than 115, it is good (○), if it is between 115 and less than 125, it is average (△), and if it is over 125, it is bad (×). It was evaluated as .

(11) Water resistance

Based on ISO 4628, the paint film was scratched and tested in a water chamber, and then the degree of rusting in the scratched and non-scratched areas was confirmed. The peeled distance from the scratched area was measured and evaluated based on ISO 4628. The peeled distance was expressed in numbers, and the smaller the value, the better the physical properties.

(12) Flowability

The flowability of the primer was measured using a Sag meter at 20°C, and the larger the value, the better the flowability.

Example One 2 3 4 5 6 7 steel blister ◎ ◎ ○ ◎ ◎ ◎ △ crosscut 0 One 0 0 0 2 0 dolly 7.1 5.3 6.8 6.5 6.7 4.1 6.6 Accelerated Cycling Endurance Test 1.1 1.3 1.4 1.4 1.3 3.4 1.4 Salt spray resistance 0.7 0.8 0.9 0.8 0.8 0.8 0.9 salt water resistance 0.7 0.8 0.8 0.9 0.8 0.8 0.8 Paintability 0 One 0 One 0 4 0 Hardness 2H 2H 2H H 2H B 2H impact resistance 0.1 0.2 0.3 0.2 0.4 0.2 One wear resistance ◎ ◎ ◎ ◎ ◎ ◎ △ water resistance 0.7 0.8 0.8 0.9 0.8 0.8 0.8 flowability 25 23 21 23 23 21 18 HDG blister ◎ ◎ ○ ◎ ◎ ◎ △ crosscut 0 One 0 0 0 3 0 dolly 5.5 5.1 5.2 5.3 5.4 3.2 5.4 Accelerated Cycling Endurance Test 1.1 1.5 1.3 1.3 1.5 3.7 1.5 Salt spray resistance 0.7 0.8 0.9 0.8 0.8 0.8 0.8 salt water resistance 0.7 0.9 0.8 0.8 0.8 0.9 0.8 Paintability 0 One 0 One 0 4 0 Hardness 2H 2H 2H H 2H B 2H impact resistance 0.1 0.2 0.3 0.2 0.4 0.3 One wear resistance ◎ ◎ ◎ ◎ ◎ ◎ △ water resistance 0.7 0.8 0.9 0.8 0.7 0.8 0.9 flowability 25 22 23 22 23 23 14

Example 8 9 10 11 12 13 14 15 steel blister ◎ ○ ◎ ◎ ○ ◎ ○ ◎ crosscut One 0 0 0 One One 0 0 dolly 5.3 6.5 6.8 6.6 5.3 5.3 6.6 6.7 Accelerated Cycling Endurance Test 1.4 1.3 1.4 1.4 1.5 1.4 1.3 1.3 Salt spray resistance 0.8 0.9 0.8 0.9 0.8 1.2 0.8 0.8 salt water resistance 0.9 0.8 0.8 0.9 0.8 One 0.8 0.8 Paintability 0 One 0 One 2 0 2 0 Hardness 2H 2H 2H 2H 2H H 2H 2H impact resistance 0.3 0.2 0.3 0.4 0.3 0.4 0.2 0.3 wear resistance ◎ ◎ ○ ◎ ○ ◎ ◎ ◎ water resistance 0.9 0.8 0.8 0.8 0.8 0.9 0.8 One flowability 21 21 23 21 21 24 21 20 HDG blister ◎ ○ ◎ ◎ ○ ◎ ○ ◎ crosscut One 0 0 0 One One 0 0 dolly 5.1 5.2 5.3 5.4 5.1 5.1 5.4 5.3 Accelerated Cycling Endurance Test 1.3 1.5 1.5 1.3 1.6 1.1 1.1 1.3 Salt spray resistance 0.8 0.8 0.8 0.9 0.8 One 0.8 0.9 salt water resistance 0.8 0.9 0.8 0.8 0.8 One 0.8 0.8 Paintability One 0 0 One 2 0 2 0 Hardness 2H 2H 2H 2H 2H H 2H 2H impact resistance 0.3 0.2 0.3 0.4 0.3 0.4 0.3 0.2 wear resistance ◎ ◎ ○ ◎ ○ ◎ ◎ ◎ water resistance 0.9 0.8 0.9 0.9 0.8 0.9 0.8 One flowability 23 22 23 23 22 23 23 20

Example 16 17 18 19 20 21 22 steel blister ◎ ◎ ◎ ◎ ◎ ◎ ◎ crosscut 0 0 0 0 0 0 0 dolly 6.4 6.4 6.5 6.8 6.6 6.8 6.7 Accelerated Cycling Endurance Test 1.2 1.2 1.2 1.5 1.4 1.3 1.3 Salt spray resistance 0.9 0.8 1.2 0.8 0.8 0.9 0.9 salt water resistance 0.9 0.8 One 0.8 0.9 0.8 0.8 Paintability 0 One 0 0 One One One Hardness 2H H 2H 2H 2H 2H 2H impact resistance 0.2 0.3 0.4 0.2 0.3 0.2 0.2 wear resistance ◎ ◎ ◎ ○ ◎ ◎ ◎ water resistance One 0.8 0.8 0.9 0.8 0.9 0.9 flowability 24 21 23 21 23 23 23 HDG blister ◎ ◎ ◎ ◎ ◎ ◎ ◎ crosscut 0 0 0 0 0 0 0 dolly 5.4 5.4 5.2 5.4 5.3 5.2 5.2 Accelerated Cycling Endurance Test 1.5 1.5 1.5 1.3 1.5 1.3 1.3 Salt spray resistance 0.8 0.9 0.8 0.8 0.8 0.9 0.9 salt water resistance 0.8 0.8 0.8 0.9 0.8 0.8 0.8 Paintability One 0 0 One 0 0 0 Hardness 2H 2H 2H 2H 2H 2H 2H impact resistance 0.3 0.3 0.3 0.2 0.1 0.3 0.3 wear resistance ◎ ◎ ◎ ◎ ◎ ◎ ◎ water resistance 0.9 0.9 0.7 0.8 0.9 0.8 0.8 flowability 23 23 23 22 23 23 23

Comparative example One 2 3 4 5 6 steel blister X ○ △ X ○ X crosscut 2 3 One 2 3 4 dolly 4.6 4.1 5.3 4.6 4.2 3.1 Accelerated Cycling Endurance Test 3.2 3.9 1.3 3.2 3.8 4.9 Salt spray resistance 2.1 1.2 1.5 2.1 1.2 3.5 salt water resistance 2.3 One 1.8 2.3 One 3.7 Paintability 2 2 One 2 2 4 Hardness H H 2H H H 2B impact resistance 0.8 2 0.4 0.9 2 3 wear resistance ○ ○ ◎ ○ ○ X water resistance 1.1 1.5 0.8 One 1.3 2.9 flowability 19 19 22 19 19 15 HDG blister X ○ △ X ○ X crosscut 2.5 3.3 One 2.7 3.5 4.6 dolly 3.4 2.8 5.1 3.3 2.9 1.5 Accelerated Cycling Endurance Test 3.5 3.9 1.3 3.5 4.1 5.8 Salt spray resistance 1.2 One 1.3 1.2 One 2.7 salt water resistance 1.3 One 1.2 1.5 One 3.1 Paintability 2 2 One 2 2 4 Hardness H H 2H H H 2B impact resistance 0.8 1.2 0.4 0.8 1.1 2.5 wear resistance ○ ○ ◎ ○ ○ X water resistance 1.1 1.5 0.8 1.1 1.6 2.6 flowability 20 20 22 20 20 15

As shown in Tables 6 to 8, the coating films prepared from the primer compositions of Examples 1 to 22 showed excellent overall physical properties.

On the other hand, as shown in Table 9, Comparative Example 1, in which the fatty acid-modified epoxy resin was not applied, had poor overall physical properties, and was particularly poor in rust prevention, salt water spray resistance, and salt water resistance. In addition, Comparative Example 2, in which the bisphenol-based epoxy resin was not applied, was also inferior in overall physical properties, and was particularly inferior in adhesion (crosscut, dolly), durability, impact resistance, and water resistance. In addition, Comparative Example 3, in which no extender pigment was applied, showed poor rust prevention, salt water spray resistance, and salt water resistance.

Comparative Example 4, in which CTBN (carboxyl terminated butadiene acrylonitrile)-modified epoxy resin was used instead of fatty acid-modified epoxy resin, was particularly poor in rust prevention, salt spray resistance, and salt water resistance, and Comparative Example 5, in which cardinol epoxy resin was used instead of bisphenol-based epoxy resin, was poor in adhesiveness. It was inferior in durability (crosscut, dolly), durability, impact resistance, and water resistance. In addition, Comparative Example 6, in which CTBN-modified epoxy resin and cardinol epoxy resin were used instead of bisphenol-based epoxy resin and fatty acid-modified epoxy resin, showed overall inferior physical properties.

Claims (5)

Contains bisphenol-based epoxy resin, fatty acid-modified epoxy resin, polyamide resin, and extender pigment,
The extender pigment includes one or more selected from the group consisting of silica, barium sulfate, talc, calcium carbonate and feldspar,
The bisphenol-based epoxy resin has a viscosity of 3,700 to 6,300 cps at 25°C, a weight average molecular weight of 1,400 to 3,100 g/mol, and a glass transition temperature of 23 to 37°C,
The fatty acid modified epoxy resin has a fatty acid modification rate of 10 to 40% by weight based on the total solid content of the epoxy resin, a viscosity at 25°C of 5,500 to 8,000 cps, a weight average molecular weight of 1,500 to 4,000 g/mol, and a glass transition. the temperature is 25 to 50℃,
The polyamide resin has a weight average molecular weight of 1,000 to 3,000 g/mol, an active hydrogen equivalent of 700 to 1,000 g/eq, an amine value of 90 to 120 mgKOH/g, and a viscosity of 5,000 to 9,000 cps at 25°C. ,
Zinc-free primer composition. In claim 1,
The bisphenol-based epoxy resin has an epoxy equivalent of 450 to 700 g/eq, a viscosity at 25°C of 4,500 to 5,500 cps, a weight average molecular weight of 1,800 to 2,400 g/mol, and a glass transition temperature of 25 to 35°C. ,
Zinc-free primer composition. In claim 1,
The fatty acid modified epoxy resin has a fatty acid modification ratio of 10 to 30% by weight based on the total solid content of the epoxy resin, an epoxy equivalent weight of 550 to 800 g/eq, a viscosity at 25°C of 6,500 to 7,500 cps, and a weight average molecular weight. It is 2,500 to 3,500 g/mol, and the glass transition temperature is 30 to 40 ℃,
Zinc-free primer composition. In claim 1,
The polyamide resin has a weight average molecular weight of 1,500 to 2,500 g/mol, an active hydrogen equivalent of 750 to 900 g/eq, an amine value of 100 to 115 mgKOH/g, and a viscosity of 6,500 to 8,000 cps at 25°C. ,
Zinc-free primer composition. In claim 1,
Comprising 1 to 15 parts by weight of fatty acid-modified epoxy resin and 20 to 40 parts by weight of extender pigment, based on 100 parts by weight of bisphenol-based epoxy resin.
Zinc-free primer composition.