JPH05271573A - Highly anticorrosive coating composition - Google Patents

Abstract

PURPOSE:To obtain a composition producing a thin and highly anticorrosive coated film. CONSTITUTION:A highly anticorrosive coating composition specifically contains 3-40wt. parts barium metaborate based on 100wt. parts (solid) resin component composed of aqueous dispersion type epoxy ester resin having 20-60 acid value and other aqueous type resins which are added as necessary. The composition is preferable for the highly anticorrosive coating composition as it dose not contain harmful pigments causing social problems and capable of obtaining a coated thin film excellent in anticorrosive property.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly anticorrosive coating composition applied for the purpose of preventing corrosion of automobile parts made of iron-based materials such as steel plates and cast iron, and other structures.

[0002]

2. Description of the Related Art Conventionally, various solvent-based paints and water-based paints have been known and used for the purpose of preventing corrosion of automobile parts made of iron-based materials such as steel plates and cast iron, and other structures.

[0003]

However, in the conventional paints for the purpose of anticorrosion, high anticorrosion properties could not be obtained without using harmful pigments such as chromium which have become a social problem recently. Further, it has a drawback that thick film coating is required to obtain high corrosion resistance without using harmful pigments. Under these circumstances, there has been a strong demand in recent years for the development of a pollution-free, highly corrosion-resistant paint that forms a coating film having excellent corrosion resistance.

[0004]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted research for the purpose of developing a pollution-free high corrosion-resistant paint that forms a coating film excellent in corrosion resistance without requiring thick film coating. I worked diligently. As a result, a resin composition containing a specific water-dispersed epoxy ester resin as a main component, a coating composition prepared by mixing a specific amount of barium metaborate, an automobile part made of an iron-based material such as a steel plate and cast iron, and other We found that by coating the structure, high corrosion resistance can be obtained with a thin film,
The present invention has been completed.

That is, according to the present invention, 3 to 40 parts by weight of barium metaborate are added to 100 parts by weight (solid content) of a resin component consisting of a water-dispersible epoxy ester resin having an acid value of 20 to 60 and other water-based resin added as necessary. The present invention relates to a highly anticorrosive coating composition, characterized by containing a part thereof.

In developing a pollution-free high corrosion-resistant coating, the present inventors have focused their attention on conventional water-dispersed epoxy ester resin-based coatings, and in order to improve the corrosion resistance of the coating film,
Research was conducted on coating hardness, water vapor permeability, resin acid value, and so on. As a result, it was presumed that the conventional corrosion of the coating film was caused by deterioration of the residual hydroxyl group in the coating film, amine as a neutralizing agent, etc. in water. It was also estimated that the concentration of the pigment to be filled and the type of the pigment also affect the water vapor permeability and cause corrosion. The present invention, based on such findings, as a result of examining various pollution-free rust-preventive pigments,
It was completed by containing a specific amount of barium metaborate.

The coating composition of the present invention will be described in detail below. The water-dispersible epoxy ester resin used as the resin component in the present invention is a polymer of an epoxy resin and an acid, and as the epoxy resin, Epicoat 828 and Epicoat 10 are used.
04, Epicoat 1007, etc. can be used. Examples of the acid include polybasic acids such as phthalic acid, maleic anhydride, isophthalic acid, and terephthalic acid, fats and oils such as linseed oil, dehydrated castor oil, safflower oil, coconut oil, and tall oil, or fatty acids extracted from these. Can be used. In addition, it may be vinylized using a vinyl-based monomer. As the vinyl-based monomer, methacrylic acid ester, glycidyl methacrylate, styrene, vinyltoluene and the like can be used.

A polyvalent amine can be used as a neutralizing agent for water solubilization after the polymerization reaction, but other amines may be used together if the main component is triethylamine. The proportion of triethylamine in all the neutralizing agents is preferably 50% or more, more preferably 70% or more, most preferably 99% or more.

In the present invention, the acid value of the above resin is 20.
It is necessary to design to -60, preferably 20 to 40, and more preferably 20 to 30. Examples of such resins include Watersol CD
There is -540 (trade name of Dainippon Ink and Chemicals, Inc.). Acid value is 6
When it exceeds 0, the amount of hydroxyl groups remaining in the coating film is extremely increased, and the coating film is easily dissolved in water, which is not preferable. Further, if the acid value is less than 20, the stability as an aqueous paint cannot be maintained, which is not preferable.

In addition to the above water-dispersible epoxy ester resin, the resin component usable in the present invention may be used in combination with other water-based resin, if necessary. As the water-based resin that can be used together, a water-soluble alkyd resin, an emulsion copolymer resin, or the like can be used. The water-dispersed epoxy ester resin and the other water-based resin are used in a solid content ratio of 50/50.
˜100 / 0 is preferable, 70/30 to 100/0 is more preferable, and 100/0 is the most preferable.

The barium metaborate used in the present invention is
Formula: BaB a compound represented by the ₂ O ₄ · H ₂ O, a need to use the resin component 100 parts by weight of barium metaborate 3-40 parts by weight with respect to (the solid content), 20 It is more preferable to use 40 parts by weight, and 2
Most preferably, 0 to 30 parts by weight is used. If the amount of barium metaborate used is less than 3 parts by weight, it will not contribute to rust prevention performance, and if it exceeds 40 parts by weight, the stability of the coating composition will be reduced.

In the coating composition of the present invention, pigments used for general coating materials may be used in addition to the above barium metaborate, in which case the pigment weight% concentration (hereinafter PWC) per coating solid content is Need to be adjusted. Considering coating workability, the PWC of the coating composition of the present invention is preferably adjusted to 35 to 70, more preferably 45 to 60. If the PWC exceeds 70, the water vapor permeability of the coating film is extremely increased, and as a result, high corrosion resistance cannot be obtained, which is not preferable.

The main pigments are extender pigments, coloring pigments, rust preventive pigments, and the like. The extender pigments are calcium carbonate,
Although extender pigments used for general paints such as silica, kaolin, barite, talc and clay can be used, it is preferable to use scaly pigments such as talc in order to reduce the water vapor permeability. As the color pigment, a color pigment such as carbon or titanium oxide used for general paints can be used. Anti-rust pigments other than barium metaborate used in the present invention can be used non-pollution type anti-rust pigments used for general paints such as zinc phosphate and zinc molybdate,
Use of a large amount is not preferable because it may reduce the stability of the coating.

In the coating composition of the present invention, in addition to the above-mentioned components, if necessary, other components used in ordinary water-based coating compositions can be used. For example, water-miscible solvents such as butyl cellosolve and isopropyl glycol, reaction accelerators such as zinc naphthenate and cobalt naphthenate, and interfacial modifiers such as silicone-based, non-silicone-based, fluorine-based, acrylic-based copolymers, etc. An organic or inorganic copolymer as a modifier and water as a diluent can be used alone or in combination.

The coating composition of the present invention is prepared by uniformly mixing and dispersing the above-mentioned respective components, and the coating film is formed by a conventionally used coating machine such as air spray coating or airless spray coating, coating equipment. It can be coated by and is dried at room temperature for about 1-2 hours.

[0016]

EXAMPLES Next, examples of the present invention will be described. All parts and% in the text are by weight.

Resin A: Epoxy resin, linseed oil, safflower oil, polybasic acid, an epoxy ester resin having an acid value of 25 consisting of a vinyl-based monomer, to which triethylamine and water are added,
By stirring, a water-dispersed epoxy ester resin having a neutralization degree of 100% and a solid content of 40% was obtained.

Resin B: Triethylamine and water are added to an epoxy ester resin having an acid value of 38 consisting of an epoxy resin, safflower oil, and a vinyl-based monomer, and the mixture is stirred and neutralized to a degree of 100.
%, Solid content 40% of water dispersion type epoxy ester resin was obtained.

Resin C: Triethylamine and water are added to an epoxy ester resin having an acid value of 42 consisting of an epoxy resin, safflower oil and a vinyl monomer, and the mixture is stirred and neutralized to a degree of 100.
%, Solid content 40% of water dispersion type epoxy ester resin was obtained.

Resin D: Triethylamine and water are added to an epoxy ester resin having an acid value of 16 consisting of epoxy resin, linseed oil, safflower oil, polybasic acid, and vinyl monomer,
By stirring, a water-dispersed epoxy ester resin having a neutralization degree of 100% and a solid content of 40% was obtained.

Resin E: Triethylamine and water are added to an epoxy ester resin having an acid value of 62 consisting of an epoxy resin, linseed oil, polybasic acid, and a vinyl monomer, and the mixture is stirred to obtain a neutralization degree of 1
A water-dispersed epoxy ester resin having a solid content of 00% and a solid content of 40% was obtained.

Resin F: Dimethylethanolamine and water are added to an epoxy ester resin having an acid value of 42 consisting of an epoxy resin, safflower oil, and a vinyl monomer, and the mixture is stirred to give water having a neutralization degree of 100% and a solid content of 40%. A dispersion type epoxy ester resin was obtained.

Example 1: Resin A 250 parts by weight, barium metaborate 30 parts by weight, talc 120 parts by weight, carbon 10 parts by weight, water 120 parts by weight, triethylamine 1 part by weight, cobalt naphthenate 2 parts by weight, and a mixture thereof. Diffusion by dispersing at high speed for 30 minutes at 30 ℃ in glass bead medium,
A coating composition was obtained.

Example 2: A coating composition was obtained in the same manner as in Example 1 except that the resin A was changed to the resin B.

Example 3: A coating composition was obtained in the same manner as in Example 1 except that the resin A was changed to the resin C.

Example 4: A coating composition was obtained in the same manner as in Example 1 except that the resin A was changed to the resin F.

Comparative Example 1: An attempt was made to obtain a coating composition according to Example 1 except that the resin A was changed to the resin D, but it could not be obtained due to thickening during dispersion.

Comparative Example 2: A coating composition was obtained in the same manner as in Example 1 except that the resin A was changed to the resin E.

Comparative Example 3: A coating composition was obtained in the same manner as in Example 1 except that 30 parts by weight of barium metaborate was changed to 2 parts by weight.

Comparative Example 4: A coating composition was obtained in the same manner as in Example 1 except that 30 parts by weight of barium metaborate was changed to 50 parts by weight, but the coating composition showed remarkable increase in viscosity at room temperature and stability. Couldn't get

Test Example 1: The coating composition of each of the above Examples 1 to 4 and Comparative Examples 2 and 3 was dried on an untreated mild steel sheet to give a dry film thickness of 2
It was coated so as to have a thickness of 0, 30, 40 μ and left at room temperature for 1 week. To confirm the corrosion resistance of the obtained coating film, JIS-
K5400, 9.1. A salt water spray test was conducted. The test results are shown in Table 1.

[0032]

[Table 1] Evaluation of salt spray resistance test: ○ indicates that the rust and blistering width from the center of the crosscut are less than 3 mm on one side. △ indicates rust from the center of the cross cut and blistering width is 3 mm or more on one side 5
Less than mm. × indicates rust from the center of the crosscut and blistering width of 5 mm or more on one side. Paint stability evaluation: ○: No significant increase in viscosity during and after coating. △ indicates a significant increase in viscosity after being made into a paint. X markedly increased the viscosity during coating.

[0033]

EFFECTS OF THE INVENTION According to the coating composition of the present invention, a coating film having excellent corrosion resistance can be obtained as a thin film without containing harmful pigments which have become a social problem recently, and therefore, a highly corrosion resistant coating composition. Is suitable as

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C08F 299/02 MRV 7442-4J

Claims (1)

[Claims] 1. A barium metaborate is contained in an amount of 3 to 40 parts by weight based on 100 parts by weight (solid content) of a resin component consisting of a water-dispersible epoxy ester resin having an acid value of 20 to 60 and other water-based resin added as required. A highly anticorrosive coating composition characterized by the above.