KR100896080B1 - Aqueous anti-corrosion paint composition - Google Patents

Abstract

The present invention relates to a water-soluble epoxy rust-preventive coating composition comprising a liquid epoxy resin as a subject and containing an aqueous solvent while containing a water-soluble epoxy curing agent, an rust-preventing pigment and the like.

Description

 Aqueous anti-corrosion paint composition

The present invention relates to a coating composition capable of imparting corrosion resistance to a plated steel sheet or a ship.

The conventional method for improving the corrosion resistance of the coated steel sheet has applied a surface treatment technique for curing the solution composition containing chromium in the form of a salt or ions on the surface of the coated steel sheet by coating or thermal drying.

Such chromium treatment is because when the material having oxidizing power against the steel sheet comes into contact with the steel sheet, corrosion of the coated steel sheet can be suppressed through a mechanism in which chromium present on the surface of the coated steel sheet is reduced and oxidized.

However, chromium (Cr ⁶⁺ ) of hexavalent ions is known to be an environmentally harmful substance that causes soil and water pollution.

In Europe, for example, since 2003, the use of steel sheets containing chromium of hexavalent ions is generally regulated, and in the home appliance field, a pretreatment product containing no chromium has been required.

In this regard, research on products that satisfy the workability and economic efficiency while retaining the corrosion resistance of the existing chromium is being conducted.

As part of this, the development of anticorrosive paint is being made, and epoxy paints are commonly used as anticorrosive paints for ships. Epoxy paints are excellent in corrosion resistance, water resistance and chemical resistance.

Anticorrosive paints such as epoxy paints use organic solvents as solvents, and paints containing organic solvents have poor workability and are harmful to the human body in confined spaces, and also include environmental pollution. Doing.

The present invention is to provide a water-soluble epoxy anti-corrosive coating composition containing no organic solvent as a solvent.

The present invention is to provide a water-soluble epoxy-based antirust coating composition containing no chromium ion.

In one embodiment of the present invention, at least 90% by weight of a liquid epoxy resin having a viscosity of 800 to 1,600 cps at 25 ° C with respect to 100% by weight of the main composition, and is an ether solvent or alcohol solvent as a miscibility improving additive. Subject composition comprising 1 to 10% by weight; 15 to 25% by weight of water-soluble epoxy curing agent, 0.2 to 1.0% by weight of dispersant, 35 to 50% by weight of pigment component including rust preventive pigment, 0.5 to 2.0% by weight of antisettling agent, and 1 to 5% by weight of curing agent composition %, 0.5 to 2.0% by weight of anti-corrosive agent, 0.2 to 1.5% by weight of antifoaming agent, and 30 to 44% by weight of water, and a water-soluble epoxy system containing the main composition and the curing agent composition in a ratio of 1: 5 to 1: 8 by weight An antirust coating composition is provided.

In one embodiment of the invention, the liquid epoxy resin in the subject composition may be a bisphenol A type epoxy resin having an epoxy equivalent of 195 to 215.

In one embodiment of the present invention, the pigment component comprising the rust preventive pigment in the curing agent composition is 5 to 10% by weight pigment, 15 to 25% by weight pigment and metal phosphate-based rust preventive pigment with respect to 100% by weight of the total curing agent composition It may comprise 15 to 25% by weight.

According to one embodiment of the present invention it is possible to provide a water-soluble epoxy-based rust-preventive coating that can obtain a pigment dispersibility as in the case of including an organic solvent while improving the working environment during painting and manufacturing.

When described in detail for each component included in the coating composition according to an embodiment of the present invention.

The epoxy resin included in the main composition is a liquid epoxy resin having a viscosity of 800 to 1,600 cps at 25 ° C., having at least two or more epoxy groups in one molecule, and specifically, a bisphenol A epoxy resin having an epoxy equivalent of 195 to 215. Can be.

In the case of a liquid epoxy resin satisfying such viscosity conditions, it may be advantageous in terms of compatibility or workability.

The main composition may consist of only liquid epoxy resin and may further include other additives, wherein the liquid epoxy resin may be included in at least 90% by weight of the total main composition.

However, such an epoxy resin is an organic resin, and may be disadvantageous in terms of miscibility in a water-soluble coating composition. As an additive for improving this point, a small amount of an ether solvent or an alcohol solvent may be used to improve miscibility or workability. It may further include as an additive. Examples of ether solvents or alcohol solvents include, but are not limited to, ethyl cellosolve, butyl cellosolve, butyl carbitol or methanol.

The ether solvent or alcohol solvent included as an additive may be included in an amount of 1 to 10% by weight based on the total main composition, in terms of compatibility, workability and storage stability.

In addition, although the composition containing the hardening | curing agent which hardens such an epoxy resin, ie, a hardening | curing agent composition, contains the hardening | curing agent for epoxy resins, Specifically, what has at least 1 primary amine group in a molecule | numerator, For example, a polyamine compound is mentioned. . Examples of the polyamine compound include aliphatic amines such as ethylenediamine, trimethylenediamine, hexamethylenediamine, octamethylenediamine, diethylenetriamine, triethylenetetraamine, and pentaethylenehexaamine, isophoronediamine, diaminocyclohexane, and 1,3. Aliphatic polyamines and alicyclic polyamines obtained from at least one or more diamines selected from alicyclic amines such as bisaminomethylcyclohexane, aliphatic amines such as orthoxylenediamine, methaxylenediamine, and m-phenylenebis (methylamine) As amines or aromatic polyamines, preferred curing agents for epoxy resins according to one embodiment of the present invention are modified alicyclic polyamines, which are water-soluble epoxy curing agents having a viscosity at 25 ° C. of 10,000 to 20,000 mPas and an amine value of 200 to 240 mgKOH / g. May be advantageous in terms of viscosity control and dispersibility under aqueous solvents. .

Such a water-soluble epoxy curing agent may be advantageous in terms of optimizing the physical properties of the paint to be included in 15 to 25% by weight of the total curable composition.

On the other hand, the curing agent composition containing a water-soluble epoxy curing agent may include pigments, additives, and the like added to the conventional anti-corrosive coating composition included in the coating composition, specifically, pigment components, dispersing agents, anti-settling agents, thickeners including anti-rust pigments , Anti-corrosive, antifoaming agent, and may include water as a solvent.

Here, the pigment component may include an rust preventive pigment, a coloring pigment, a extender pigment, and the content thereof may be 35 to 50% by weight of the total curing agent composition.

As a specific example, the extender pigment serves to fill pores in the coating film and to control the complement and gloss of hardness and chemical properties, and specific examples thereof include barite, talc, mica, silica, and the like. By using a mixture of two or more species, a good coating film appearance can be obtained, and rust resistance and the like can be improved. In the case of including the extender pigment, it may be advantageous to include 15 to 25% by weight of the total curing agent composition.

Examples of the rust preventive pigment include phosphate rust preventive pigments of metal oxides, and examples thereof include phosphate solutions such as aluminum, manganese, zinc, and molybdenum fluoride, phosphate solutions of hexaammonium hepta molybdate hydrate, and phosphate solutions of soda. Can be mentioned. Such rust preventive pigments can be used by 1 type, or 2 or more types of mixtures. It may be advantageous to include such antirust pigments in an amount of 15 to 25% by weight of the total curing agent composition.

On the other hand, as a coloring pigment can be used a variety of pigments that express the color, it may be advantageous to be a brown-based colored pigment in consideration of the purpose of rust prevention, moreover it can perform the functions of coloring and rust prevention together, non-toxic, stable and water resistance In terms of good chemical resistance, it may be advantageous to use iron oxide (Fe ₂ O ₃ ) as a coloring pigment.

The content of the coloring pigment may be 5 to 10% by weight of the total curing agent composition.

On the other hand, the dispersant is adsorbed on the surface of the pigment to prevent the pigments from re-aggregating by maintaining a constant gap between the pigment and the pigment due to the electric repulsive force or steric hindrance effect, for example, silicone or non-silicone dispersant Can be mentioned.

The content of such a dispersant may be advantageous in terms of maximizing dispersibility of 0.2 to 1.0% by weight of the total curing agent composition.

The antisettling agent serves to prevent the precipitation of the pigment. According to one embodiment of the present invention, when the pigment is mixed with water, the specific gravity of the pigment is large so that it may sink and harden to inhibit pigment dispersion. Can be. This may inhibit rust resistance or even appearance of color. In consideration of this, the coating composition according to the embodiment of the present invention includes a sedimentation inhibitor, and the present invention is not particularly limited, but an example may include bentonite or fumed silica. In terms of storage stability, it may be a bentonite-based sedimentation inhibitor.

The amount of the anti-settling agent may be advantageous in terms of optimizing the storage stability of 0.5 to 2.0% by weight of the total curing agent composition.

On the other hand, in forming the coating film, it may advantageously include a thickener in terms of smoothness, that is, helping to form the coating film. In view of the fact that the coating composition according to the present invention is a water-soluble epoxy paint, it is advantageous that the water-soluble thickener is more advantageous. It may be an acrylic thickener.

The content of the thickener may be 1 to 5% by weight of the total curing agent composition may be advantageous in terms of coatability and workability.

On the other hand, due to the addition of the rust preventive pigment can be achieved durable rust resistance, may further include a separate rust inhibitor for the initial corrosion inhibition.

Here, the rust inhibitor may include sodium nitrite or sodium benzoate, but is not limited thereto. The amount of the anti-rust agent is preferably 0.5 to 2.0% by weight of the total curing agent composition.

The antifoaming agent is for preventing the coating film bonding, such as the generation of bubbles in the coating film, when the bubbles remain in the coating film may result in poor adhesion to the body or deterioration of physical properties. Examples of the antifoaming agent include mineral oil, silicone, non-silicone, etc. In one embodiment of the present invention, a silicone antifoaming agent may be used in terms of maximizing defoaming power. The content of the silicone antifoaming agent may be 0.2 to 1.5% by weight of the total curing agent composition.

On the other hand, water included as a solvent may be used in 30 to 44% by weight of the total curing agent composition.

The inclusion of various pigments and additives including the curing agent for epoxy resins in the curing agent composition is because it is advantageous in terms of dispersibility or coating film formation to induce even dispersion of the pigment and the like in the aqueous solvent and to mix the organic resin.

The water-soluble epoxy anticorrosive coating composition according to the embodiment of the present invention may be obtained by including the above-described main composition and the curing agent composition in a weight ratio of 1: 5 to 1: 8. If the ratio of the curing agent composition is too small, the crosslinking reaction may not be completed. As a result, the coating film may not be dense, and thus physical properties such as rust resistance may be lowered. If the content of the main composition is excessive, an unreacted curing agent may be left, which may cause problems such as amine blushing.

Although there is no particular limitation on the method for producing a water-soluble epoxy anticorrosive coating composition that satisfies such a composition, an example of an optimal method may be as follows in consideration of using an aqueous solvent.

First, the above-mentioned water-soluble epoxy curing agent and dispersant are dispersed in water. In this case, the amount of water used may be 14 to 20% by weight of the total curing agent composition in terms of dispersibility.

The pigment component, antisettling agent and thickener are mixed and dispersed together with water. At this time, the amount of water used may be advantageous in terms of dispersibility of 18 to 24% by weight of the total curing agent composition.

Thereafter, the rust preventive agent, the antifoaming agent, and water are mixed and dispersed therein, wherein the amount of water used may be advantageous in terms of dispersibility of 0.1 to 2% by weight of the total curing agent composition.

After obtaining a curing agent composition as described above, it is mixed and dispersed together with the main composition including a liquid epoxy resin to obtain a water-soluble epoxy anti-corrosive coating composition according to an embodiment of the present invention.

The water-soluble epoxy antirust coating composition according to one embodiment of the present invention can improve the working environment and prevent environmental pollution by using an aqueous solvent while satisfying the pigment dispersibility as in the conventional organic epoxy antirust coating composition. It can be safe from fire.

As a coating method of such a water-soluble epoxy antirust coating composition, conventionally known methods such as an air spray, an airless spray, a roller, and a brush can be adopted. It may be advantageous in terms of ease.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.

<Example 1>

Curing agent composition

17 wt% water-soluble epoxy curing agent (modified aromatic polyamine epoxy curing agent having an amine value of 200 to 240 mgKOH / g and a viscosity of 10,000 to 20,000 mPas at 25 ° C), 0.4 wt% of silicone-based dispersant (by KK), and 14 wt% of water The mixture was dispersed and stirred at low speed (hereinafter, referred to as first step).

Here, 8% by weight of iron oxide (Fe ₂ O ₃ ), 20.4% by weight of talc as a extender pigment, 15% by weight of zinc phosphate rust preventive pigment, 1% by weight of bentonite-based anti-settling agent, 2 parts by weight of acrylic thickener mixed with 20% by weight of water Dispersion (hereinafter referred to as second step).

Finally, 100% by weight of a curing agent composition was prepared by mixing and dispersing 1% by weight of sodium nitrite and 0.6% by weight of a silicone antifoaming agent together with 0.6% by weight of water (hereinafter referred to as a third step).

Theme composition

92 weight% of liquid epoxy resin (epoxy equivalent 195 to 215 g / eq and bisphenol A liquid epoxy resin having a viscosity of 800 to 1600 cps at 25 ° C.) and 8 weight% of ethyl cellosolve were mixed and dispersed at low speed (hereinafter, Step 4).

The curing agent composition and the main composition obtained above were mixed at a 7: 1 weight ratio, and mixed and dispersed by a slow stirring method to prepare a water-soluble epoxy antirust coating composition.

<Examples 2 to 5>

As shown in Table 1, a water-soluble epoxy rust-preventive coating composition was prepared in the same manner as in Example 1 by varying the composition ratio.

In the description of the tables below, the content units are expressed in weight percent based on the weight of each composition, that is, 100 weight percent of the curing agent composition or 100 weight percent of the main composition.

Example 1 Example 2 Example 3 Example 4 Example 5 Curing agent composition (100 wt%) First step water 14 14 14 14 14 Water Soluble Epoxy Curing Agent 17 14 16 19 21 Silicone Dispersant 0.4 0.4 0.4 0.4 0.4 2nd step water 20 20 20 18 15.6 Iron oxide 8 8 8 8 8 Sieving pigment 20.4 20.4 20.4 20.4 20.4 Antirust Pigment 15 15 15 15 15 Sedimentation inhibitors One One One One One Thickener 2 2 2 2 2 3rd step water 0.6 3.6 1.6 06 One Rust preventive One One One One One Antifoam 0.6 0.36 0.6 0.6 0.6 Theme composition (100 wt%) 4th step Liquid epoxy resin 92 92 92 92 92 Ether solvent 8 8 8 8 8 Curing agent composition: Main composition weight ratio 7: 1 8: 1 7: 1 6: 1 6: 1

Reference Example

As shown in Table 2, a water-soluble epoxy rust-preventive coating composition was prepared in the same manner as in Example 1 by varying the composition ratio.

In the description of the tables below, the content units are expressed in weight percent based on the weight of each composition, that is, 100 weight percent of the curing agent composition or 100 weight percent of the main composition.

Reference Example 1 Reference Example 2 Reference Example 3 Curing agent composition (100 wt%) First stage water 14 14 14 Water Soluble Epoxy Curing Agent 17 16 19 Silicone Dispersant 0.4 0.4 0.4 2nd step water 20 20 18 Iron oxide 8 8 8 Sieving pigment 20.4 20.4 20.4 Antirust Pigment 15 15 15 Sedimentation inhibitors One One One Thickener 2 2 2 3rd step water 0.6 1.6 0.6 Rust preventive One One One Antifoam 0.6 0.6 0.6 Theme composition (100 wt%) 4th step Liquid epoxy resin 92 92 92 Ether solvent 8 8 8 Curing agent composition: Main composition weight ratio 7: 1 7: 1 6: 1 Liquid epoxy resin: Epoxy resin with viscosity of 8,000-14,000 cps at 25 ° C

Experimental Example

Specific Gravity, Viscosity, Tack Drying Time and Solidification Time, Pot life, Rust Resistance, Adhesiveness, H ₂ O Dilution Stability, Spray Workability for Coating Compositions Obtained According to Examples 1 to 5 and Reference Examples The results are shown in Table 3 below.

The specific measuring method is as follows.

(1) specific gravity

Test method 2131 of KSM 5000 was followed.

(2) viscosity

Test method 2122 of KSM 5000 was followed.

(3) Drying time at 25 ℃

Test method 2511 of KSM5000 was followed.

(4) solidification time at 25 ° C

Test method 2511 of KSM 5000 was followed.

(5) Pot life at 25 ℃

About 250 ml of the sample mixed according to the mixing ratio of the main agent and the curing agent was placed in a can or glass bottle having a volume of 300 ml and an inner diameter of 70-80 mm, and the contents were examined at the prescribed pot life. The mixture was mixed with a glass rod to determine whether there was no sedimentation of the pigment, and if it could be easily dispersed in a uniform state, and whether there was no severe viscosity increase and gelation compared to immediately after mixing.

(6) antirust

Salt spray test According to KS D 9502. However, three specimens were made and the time for spraying brine was 120 hours.

As a result, when two or more of the three specimens had no wrinkles, swelling or cracking, they were evaluated as ○.

(7) adhesion

According to ASTM D 3359 (Measuri's Adhesion By Tape Test) Method B-Cross-cut Tape Test method, if there is no coating peeling, grade 5 is grade 4, grade 3, grade 2, grade 1 and 65% or more The case of this peeling state was evaluated as 0 grade.

(8) H ₂ O Dilution Stability

Dilution stability was evaluated according to Test Method 2311 of KSM 5000 by diluting the obtained paint composition with water as a diluent in a 5: 1 volume ratio. (Circle) excellent cases, (circle) and excellent cases were evaluated as (circle), and normal case was (triangle | delta) and bad case was evaluated as x.

(9) spray workability

Evaluated according to Test Method 2412 of KSM 5000, the coated steel sheet was placed almost vertically using the coating composition and irradiated with running, fogging, and after drying, dusting, spots and colors. Investigate stains, bubbles, wrinkles, pinholes, cratering, blushing, etc. Evaluated as.

Example Reference Example One 2 3 4 5 One 2 3 Specific gravity (kg / ℓ) 1.16 ± 0.02 1.16 ± 0.02 1.16 ± 0.02 1.16 ± 0.02 1.16 ± 0.02 1.16 ± 0.02 1.16 ± 0.02 1.16 ± 0.02 Viscosity (ku / 25 ℃) 75 ± 3 74 76 77 78 80 85 90 Dry touch time (min) 30 20 20 25 25 20 20 25 Solidification time (hrs) 6 4 4 5 5 4 4 5 Pot life (hrs) One One One One One 40 minutes 40 minutes 40 minutes Antirust (Saline Spray 120hrs) ○ ○ ○ ○ ○ ○ ○ ○ Adhesion (Grade) 5 5 5 5 5 4 4 4 H ₂ O Dilution Stability ◎ ○ ○ ○ ○ △ △ △ Spray workability ◎ ○ ○ ○ ○ △ △ △

It can be seen that the coating compositions according to Examples 1 to 5 are excellent in dilution stability with respect to water and excellent spray workability even though they are not organic coating compositions. This makes it possible to replace the organic rust-preventive paint that causes problems such as environmental problems, working environment problems or fire occurrence as an anti-corrosive paint that is an aqueous composition.

Claims (4)

At least 90% by weight of a liquid epoxy resin having a viscosity of 800 to 1,600 cps at 25 ° C., and 1 to 10% by weight of an ether solvent or an alcohol solvent as a miscibility improving additive, based on 100% by weight of the main composition Topic composition; 15 to 25% by weight of water-soluble epoxy curing agent, 0.2 to 1.0% by weight of dispersant, 35 to 50% by weight of pigment component including rust preventive pigment, 0.5 to 2.0% by weight of antisettling agent, and 1 to 5% by weight of curing agent composition %, 0.5 to 2.0 wt% rust inhibitor, 0.2 to 1.5 wt% defoamer, and 30 to 44 wt% water, A water-soluble epoxy anticorrosive coating composition comprising a main composition and a curing agent composition in a weight ratio of 1: 5 to 1: 8. The water-soluble epoxy anticorrosive coating composition according to claim 1, wherein the liquid epoxy resin is a bisphenol A epoxy resin having an epoxy equivalent weight of 195 to 215. delete The pigment component according to claim 1, wherein the pigment component comprising the rust preventive pigment in the curing agent composition is 5 to 10% by weight of the coloring pigment, 15 to 25% by weight of the extender pigment and 15 to 25 of the metal phosphate-based rust preventive pigment based on 100% by weight of the total curing agent composition. Water-soluble epoxy-based rust preventive coating composition, characterized in that it comprises a weight%.