Paint compositions, metal equipment, metal components, and metal structures, as well as methods for corrosion prevention, rust prevention, or rust replacement thereof.

Abstract

The objective is to provide a paint composition that possesses uniformity, corrosion or rust prevention, and water resistance and durability. [Solution] The above problem can be solved by a metal coating composition containing (A) styrene-acrylic acid copolymer resin, (B) solvent, (C) tannin, (D) anionic surfactant or nonionic surfactant, and (E) water.

Description

Technical Field

[0001] The present invention relates to a paint composition. The present invention also relates to a metal device, a metal member, or a metal structure including the paint composition. The present invention also relates to a method for preventing corrosion, rust, or replacing rust of a metal device, a metal member, or a metal structure.

Background Art

[0002] Metal materials are widely used in various industrial fields because of their excellent mechanical strength and workability. However, metal materials are exposed to corrosive substances such as oxygen, moisture, or chloride ions in the air, which causes corrosion and rust to progress, leading to deterioration of appearance, reduction of mechanical properties, and ultimately shortening of the life of the entire structure. Therefore, corrosion prevention or rust prevention treatment is widely performed on metal materials.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For anticorrosive or rust-preventive paints, since tannin, which is a water-soluble substance, is dissolved in the paint, most of them are based on water-based paints (Patent Document 1). Water-based paints generally have the demerit of "being difficult in water resistance" compared with oil-based paints. As a result, repainting at regular intervals or overcoating with a paint having excellent durability and water resistance is required, and thus the solution of the problem has been desired. On the other hand, it was speculated that when an oil component having excellent water resistance was blended, the uniformity of the paint would decrease.

Means for Solving the Problems

[0005] The inventors diligently researched metal coating compositions that possess uniformity, corrosion or rust prevention, and water resistance and durability. Surprisingly, they discovered that a metal coating composition possessing these properties can be obtained by combining components A to E. This invention is based on these findings. Therefore, the present invention relates to the following invention. [1] A metal coating composition comprising (A) styrene-acrylic acid copolymer resin, (B) solvent, (C) tannin, (D) anionic surfactant or nonionic surfactant, and (E) water. [2] The composition described in [1] for rust prevention and / or rust replacement. [3] The composition according to [1] or [2], which is in the form of an emulsion. [4] (A) Styrene-acrylic acid copolymer resin in an amount of 3 to 50% by mass based on the total amount of the composition. (B) Solvent in an amount of 40-90% by mass based on the total amount of the composition. (C) Tannins are 0.5 to 15% by mass based on the total amount of the composition. (D) Anionic surfactant or nonionic surfactant in an amount of 0.5 to 15% by mass based on the total amount of the composition, (E) Water in 1 to 40% by mass based on the total amount of the composition A composition containing any of [1] to [3]. [5] Metal equipment, metal components, or metal structures comprising a coating and / or black rust formed by any of the compositions described in [1] to [4]. [6] A method for corrosion prevention, rust prevention, or rust replacement of metal equipment, metal components, or metal structures, comprising applying a composition described in any of [1] to [4] to the surface of the metal equipment, metal components, or metal structures. [Effects of the Invention]

[0006] According to the present invention, a metal coating composition can be obtained that possesses uniformity, corrosion or rust prevention, and water resistance and durability. [Modes for carrying out the invention]

[0007] Embodiments of this specification will be described below. However, the embodiments described below are merely illustrative, and there is no intention to exclude various modifications or applications of techniques not explicitly stated below. The present invention can be implemented in various ways without departing from its spirit.

[0008] In this specification, unless otherwise specified, the notation "a~b" for numerical values ​​a and b shall be equivalent to "a or greater and b or less." That is, the notation "a~b" includes both numerical values ​​a and b. If a unit is attached only to numerical value b in such notation, that unit shall also apply to numerical value a.

[0009] (Component A: Styrene-acrylic acid copolymer resin) The composition of the present invention comprises a styrene-acrylic acid copolymer resin as component A. In this specification, "styrene-acrylic acid copolymer" means a copolymer comprising styrene or its derivatives, which are aromatic vinyl compounds (e.g., α-methylstyrene, p-methylstyrene, etc.), and acrylic acid or its esters having carboxyl groups (e.g., ethyl acrylate, butyl acrylate) as constituent units. The type of copolymer is not particularly limited as long as the effects of the present invention are obtained, and may be a random copolymer, graft copolymer, block copolymer, or core-shell copolymer. The carboxyl groups derived from acrylic acid may be partially or completely neutralized with sodium hydroxide, ammonium hydroxide, triethanolamine, etc.

[0010] Component A may be prepared in-house or purchased commercially. Commercially available components include Pliolite AC-4 (Synthomer), Acronal S790, Acronal S728, Acronal S504 (all manufactured by BASF), and VINAVIL 6713, which can be used individually or in combination of two or more. Pliolite and Acronal are registered trademarks.

[0011] The content of component A in the total composition is not particularly limited as long as the effects of the present invention are obtained, but for example it can be 3 to 50% by mass, preferably 5 to 40% by mass, more preferably 8 to 35% by mass, and most preferably 10 to 30% by mass. By setting the content of component A to 3% by mass or more, a uniform coating film can be formed and the uniformity of the coating film can be improved. By setting the content of component A to 50% by mass or less, an appropriate viscosity and applicability can be obtained.

[0012] (Component B; Solvent) The composition of the present invention contains a solvent as component B. The solvent is not particularly limited as long as it is an organic solvent that can dissolve component A, and one or more solvents such as paraffinic solvents, mineral oil-based solvents, aromatic solvents, alcohol-based solvents, and glycol ether-based solvents can be used in combination.

[0013] Examples of paraffinic solvents include straight-chain or branched-chain solvents made of saturated hydrocarbons. For example, paraffin, isoparaffin, n-hexane, n-heptane, n-dodecane, isododecane, and isohexane can be used. Examples of mineral oil-based solvents include medium-volatile to high-boiling point hydrocarbon mixtures obtained by refining petroleum fractions. For example, mineral spirits, kerosene, and naphtha-based solvents can be used. Examples of aromatic solvents that can be used include toluene, xylene, and ethylbenzene. As the alcohol-based solvent, for example, ethanol, isopropyl alcohol, isobutanol, isobutyl alcohol, etc. can be used. Examples of the glycol ether-based solvent include propylene glycol and ethylene glycol. As propylene glycol, for example, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, etc. can be used. As ethylene glycol, for example, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, etc. can be used.

[0014] The content of component B based on the total amount of the composition is not particularly limited as long as the effects of the present invention can be obtained, but for example, it can be 40 to 90% by mass, preferably 45 to 85% by mass, more preferably 50 to 80% by mass, and most preferably 55 to 75% by mass.

[0015] (Component C; tannin) The composition of the present invention contains tannin as component C. Tannin is known to form a complex with a metal that is easily ionized. Utilizing this, methods of corrosion-proofing zinc or coating various metals such as magnesium and aluminum to achieve antibacterial properties have been investigated.

[0016] As tannin, hydrolyzable tannin (for example, tannic acid, gallotannin, ellagitannin, etc.) or salts thereof (sodium salt, ammonium salt) in which gallic acid or ellagic acid is ester-bonded to a sugar such as glucose and is easily hydrolyzed by an acid or an enzyme, and condensed tannin (for example, proanthocyanidin, etc.) in which a compound having a flavanol skeleton is polymerized can both be used. These tannins can be used alone or in combination of two or more. Tannin may be a synthesized one or an extracted one from plants, etc. Since the reactivity with a metal is good, it is preferable to use hydrolyzable tannin.

[0017] The content of component C in the total composition is not particularly limited as long as the effects of the present invention are obtained, but can be, for example, 0.5 to 15% by mass, preferably 0.8 to 12% by mass, more preferably 1 to 10% by mass, and most preferably 2 to 8% by mass. By setting the content of component C to 0.5% by mass or more, corrosion resistance, rust prevention, and / or rust substitution properties can be enhanced. By setting the content of component C to 15% by mass or less, the strength and durability of the coating film can be enhanced.

[0018] (Component D; anionic surfactant or nonionic surfactant) The composition of the present invention comprises one or more anionic surfactants or nonionic surfactants as component D. Anionic surfactants are preferred because they provide emulsification stability when the formed emulsion particles become charged. The anionic surfactant is not limited as long as the effects of the present invention are obtained, and anionic surfactants such as sulfonate type, sulfate ester type, carboxylate type, succinate type, and phosphate ester type can be used individually or in mixtures. Sulfonate-type anionic surfactants refer to surfactants that have a salt of a sulfonic acid group (e.g., sodium salt, ammonium salt, potassium salt, etc.) as their hydrophilic group. Specific examples include sodium dodecylbenzenesulfonate and sodium alkylenedisulfonate. Sulfate ester type anionic surfactants refer to anionic surfactants that have a structure in which a sulfate group is ester-bonded to an aliphatic alcohol. Specific examples include sodium lauryl sulfate and sodium laureth sulfate. Carboxylate salt-type anionic surfactants refer to anionic surfactants that have a structure in which the carboxylic acid group (-COOH) of a fatty acid is a salt (e.g., a sodium salt). Specific examples include sodium lauryl sulfate and sodium stearate. Succinate-type anionic surfactants refer to anionic surfactants that have a succinic acid skeleton and a structure in which a sulfonic acid group is introduced to part or all of it. Specific examples include disodium monoalkyl succinate sulfonate and sodium dialkyl succinate sulfonate. Phosphate ester salt type anionic surfactants refer to anionic surfactants that have a structure in which an alcohol and phosphoric acid are ester-bonded. Specific examples include sodium lauryl phosphate and sodium polyoxyethylene lauryl phosphate.

[0019] The lower limit of the HLB value for nonionic surfactants can be 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10, 11, 12, 13, 14, or 15, but is not limited to the following. As for nonionic surfactants, it is preferable to use those with an HLB value in the range of 7.0 to 18, and more preferably those with an HLB value in the range of 15 to 18. Generally, when forming w / o type emulsions between mineral oil or nonpolar solvents and aqueous solutions, an HLB value of around 6.0 to 9.0 is considered suitable. However, in the present invention, as shown in the examples described later, a relatively higher HLB value results in more stable emulsification. One reason for this is presumed to be that the styrene-acrylic acid copolymer resin behaves as a kind of protective colloid due to the interaction between the acrylic acid structure of the styrene-acrylic acid copolymer resin and the hydrophilic groups in the surfactant.

[0020] The nonionic surfactant is not limited to those that provide the effects of the present invention, and nonionic surfactants such as ether-type, sugar-type, and ester-type surfactants can be used individually or in mixtures. Ether-type nonionic surfactants have a polyoxyethylene chain (-(CH2CH2O)) as their hydrophilic group. nThis refers to nonionic surfactants having a (-) and a structure in which an aliphatic or aromatic hydrocarbon chain is bonded as a hydrophobic group. Specific examples include polyoxyethylene castor oil ether, polyoxyethylene lauryl ether, polyoxyethylene isodecyl ether, polyoxyethylene polycyclic phenyl ether, and polyoxyethylene nonylphenyl ether. Sugar-type nonionic surfactants refer to nonionic surfactants that have a sugar structure or derivative thereof as a hydrophilic group, such as sorbitol, glucose, or maltose, and a fatty acid or alkyl group as a hydrophobic group. Specific examples include alkyl glucosides, sorbitan fatty acid esters (e.g., sorbitan oleate), and polyoxyethylene sorbitan fatty acid esters. Ester-type nonionic surfactants refer to nonionic surfactants obtained by ester bonding of glycerin, sucrose, sorbitol, or polyols with fatty acids. Specific examples include glyceryl stearate and sucrose laurate ester.

[0021] The content of component D in the total composition is not particularly limited as long as the effects of the present invention are obtained, but can be, for example, 0.5 to 15% by mass, preferably 0.8 to 12% by mass, more preferably 1 to 10% by mass, and most preferably 2 to 8% by mass. By setting the content of component D to 0.5% by mass or more, the uniformity of the paint can be improved. By setting the content of component D to 15% by mass or less, the strength and durability of the coating film can be improved. The above content is the total amount if both anionic surfactants and nonionic surfactants are included.

[0022] (Component E: Water) The composition of the present invention contains water as component E for dissolving component D. The content of component E on a basis of the total composition is not particularly limited as long as the effects of the present invention are obtained, but can be, for example, 1 to 40% by mass, preferably 2 to 30% by mass, more preferably 3 to 25% by mass, and most preferably 5 to 20% by mass.

[0023] The mass ratio of the content of component A to the content of component B (content of component A / content of component B) can be 0.02 to 2.0, 0.05 to 1.5, 0.1 to 1.0, or 0.2 to 0.8. The mass ratio of the content of component C to the content of component E (content of component C / content of component E) can be 0.02 to 2.0, 0.05 to 1.5, 0.1 to 1.0, or 0.2 to 0.8. The mass ratio of component B content to component E content (component B content / component E content) can be 1 to 15, 2 to 12, or 3 to 10. It is preferable that component B is present in a larger quantity than component E.

[0024] The compositions of the present invention may optionally contain additives such as pH adjusters (citric acid, phosphoric acid, EDTA, etc., and their alkali metal salts), defoamers (silicone resin, etc.), viscosity modifiers (silica, alumina, layered compounds, etc.), and colorants (carbon black, etc.). These additives may be included individually or in mixtures.

[0025] (Metal coating composition) The compositions of the present invention can be used in equipment, components, or structures made from metals such as iron, steel, zinc, aluminum, copper, magnesium, tin, lead, nickel, chromium, titanium, molybdenum, tungsten, cobalt, manganese, palladium, platinum, gold, silver, indium, cadmium, zirconium, hafnium, tantalum, iridium, ruthenium, and rhodium, or alloys thereof (for example, brass, bronze, nickel silver, aluminum alloy, magnesium alloy, titanium alloy, nickel alloy, Stellite, Inconel, etc.). The compositions of the present invention are preferably used in equipment, components, or structures made from easily ionizable metals that form complexes with tannins, such as iron, aluminum, zinc, magnesium, titanium, copper, tin, cobalt, nickel, or alloys thereof (carbon steel, cast iron, stainless steel, chromium steel, magnesium steel, nickel steel, molybdenum steel, vanadium steel, silicon steel, manganese steel, tungsten steel, cobalt steel, brass, bronze, nickel silver, aluminum alloy, magnesium alloy, titanium alloy). It is believed that tannins and these metals form complexes, creating an effective corrosion-resistant film. The compositions of the present invention are particularly preferably used for corrosion prevention, rust prevention, or rust replacement on the surfaces of equipment, components, or structures made of iron or iron-containing alloys (e.g., carbon steel, cast iron, stainless steel, chromium steel, magnesium steel, nickel steel, molybdenum steel, vanadium steel, silicon steel, manganese steel, tungsten steel, etc.). The compositions of the present invention are most preferably used on the surfaces of iron or iron-containing alloys that have already developed red rust. By using the compositions of the present invention on the surfaces of iron or iron-containing alloys that have already developed red rust, the red rust can be converted to black rust. In iron or iron-containing alloys, if rust has already progressed, it is necessary to remove the rust with a wire brush or the like before coating with a rust inhibitor. By using the composition of the present invention, this process can be omitted.

[0026] The composition of the present invention is an oil-based, one-component liquid paint in which tannin, which has rust substitution properties and corrosion-preventive and rust-preventive film-forming properties, is stably emulsified and dispersed in a mixture based on a hydrophobic resin (styrene-acrylic acid copolymer resin) with excellent water resistance and durability. Therefore, compared to two-component paints, the effort required for mixing during use can be reduced. Furthermore, since no synthetic chemical processes are required to prepare the composition of the present invention, the manufacturing process is simplified and costs are reduced.

[0027] (Properties) The composition of the present invention is not limited in its properties as long as the effects of the present invention are obtained, and may be in liquid or paste form. The composition of the present invention is preferably liquid, and more preferably emulsion.

[0028] (Metal equipment, metal components, or metal structures) Examples of applications of the composition of the present invention to metal equipment, metal components, or metal structures are listed below. • Automobile body, frame, chassis, suspension components (arms, suspension brackets, etc.), muffler, fuel tank, door hinges, etc. • Metal components used in building materials, especially steel materials (H-beams, square pipes, steel pipes, reinforcing bars, etc.) • Railway vehicle body structure, bogie section, coupling device, rails, etc. Metal components, especially steel, used in high-humidity environments where corrosion is likely to occur. • Outdoor structures made of metal (bridges, elevated roads, handrails, guardrails, road signs, pillars, etc.) • Offshore structures made of metal (ships, port facilities, containers, cranes, dock rails, steel ladders, mooring facilities, etc.) • Other metal structures (agricultural machinery, construction machinery, air conditioning equipment, etc.).

[0029] (Application) The method of applying the composition of the present invention to metal equipment, metal components, or metal structures is not particularly limited, and sprays, brushes, rollers, etc., can be used. Metal equipment, metal components, or metal structures may also be immersed in a container filled with the composition of the present invention.

[0030] Furthermore, the composition of the present invention may be used to treat metal equipment, metal components, or metal structures that already show signs of corrosion or rust, or it may be used to treat metal equipment, metal components, or metal structures that do not yet show signs of corrosion or rust. [Examples]

[0031] The present invention will be specifically described below with reference to examples, but these examples are not intended to limit the scope of the invention. Unless otherwise specified, % refers to mass %.

[0032] (Examples 1-15) The raw materials were stirred with a magnetic stirrer according to the formulations described in Tables 1 and 2 to prepare the paint. The classification, compound name, and HLB value of the surfactants used (in the case of nonionic surfactants) are summarized in Table 6, and the resins, solvents, tannins, and additives are summarized in Table 7. In Examples 7 and 8, Newcol 1533 and Newcol 80 were blended separately. This is because HLB values ​​are additive, and by mixing Newcol 1533 and Newcol 80, the HLB value of Example 7 was adjusted to 8.3 and the HLB value of Example 8 to 7.3.

[0033] (Comparative Examples 1-6) The raw materials were stirred with a magnetic stirrer according to the formulations shown in Tables 3-5 to prepare the paint. The classification, compound name, and HLB value of the surfactants used (in the case of nonionic surfactants) are summarized in Table 6, and the resins, solvents, tannins, and additives are summarized in Table 7. Comparative Example 2 incorporates the aqueous acrylic resin Watersol S-745.

[0034] 1. Evaluation of emulsification stability The paints of the examples and comparative examples were placed in sample bottles and left to stand at room temperature for 24 hours. The degree to which emulsification was maintained was visually evaluated after 30 minutes and 24 hours. The evaluation criteria were as follows: ◎ indicates complete emulsification after 24 hours; ○ indicates good emulsification overall, although there is some sedimentation or floating of liquid after 24 hours; △ indicates emulsification after 30 minutes but deemulsification after 24 hours; and × indicates significant deemulsification within a few minutes of standing. × was considered outside the acceptable range for the product. Note that comparative example 2, which contained a water-soluble resin, was not evaluated because emulsification stability did not need to be considered.

[0035] 2. Evaluation of the performance in converting red rust to black rust. A 40mm x 80mm (1.2mm thick) JIS G3141 cold-rolled steel sheet was polished with #240 grit waterproof sandpaper. Next, the steel sheet was exposed to a 35°C, 5% salt spray (JIS Z2371:2015) for 24 hours, after which it was lightly washed with tap water and a brush to obtain a steel sheet with red rust forming all over. The paints of the example and comparative example were applied to half of the above-mentioned red rusted steel plate, and the degree of black rust was visually evaluated after 24 hours. We rated surfaces with very deep black rust as ◎, those with sufficient black rust as ○, and those with no black rust as ×.

[0036] 3. Evaluation of the salt spray resistance of the paint. Red rust steel plates coated with the paints of the examples and comparative examples were exposed to a 35°C, 5% salt spray incubator for 24 hours. After exposure, the test pieces were removed and lightly washed with tap water and a brush. The rust formation from beneath the coated areas of the test pieces and the maintenance of the coating film were visually observed to evaluate the salt spray durability. This evaluation allows for the assessment of corrosion prevention or rust prevention, as well as water resistance and durability. ◎ indicates that the paint film was uniformly preserved after salt spraying and no rust occurred from the substrate in the coated area; ○ indicates that there were some uneven areas in the paint film but no rust occurred from the substrate; △ indicates that the paint film was uneven and some rust was observed from the substrate; and × indicates that the paint film was uneven and a lot of rust was observed from the substrate.

[0037] [Table 1]

[0038] [Table 2]

[0039] [Table 3]

[0040] [Table 4]

[0041] [Table 5]

[0042] [Table 6]

[0043] [Table 7]

[0044] (Evaluation of Examples 1-16) Examples 1-15, which contained all components A-E, all showed good emulsification stability, black rust substitution properties, and salt spray resistance. In Example 16, the uniformity of the emulsification was slightly lower compared to the other examples, but the salt spray resistance was good and it was judged to be within an acceptable range for the product. All of Examples 1-16 were in the form of an emulsion. Here, the corrosion resistance of the present invention is obtained by the reaction of tannin and metal to form a complex, and then by coating the surface with a highly water-resistant and durable hydrophobic resin. Therefore, if various metals other than steel plates can react with tannin to form a stable complex, it is thought that corrosion resistance can be obtained by the present invention in the same way as in the examples.

[0045] (Evaluation of Comparative Examples 1-6) In Comparative Example 1, which contained a cationic surfactant instead of component D, the composition did not emulsify and did not result in a uniform paint. In Comparative Example 2, which contained an aqueous acrylic resin instead of component A, good salt spray resistance was not obtained. This was thought to be because the composition of Comparative Example 2 was poor at allowing water and ion permeability. . In Comparative Examples 3-6, which contained various hydrophobic resins instead of component A, satisfactory results were not obtained for at least one evaluation item. In Comparative Example 3, the uniformity of the emulsion deteriorated, and cracks were observed in the coating film after salt spraying. In Comparative Example 4, significant phase separation occurred on the steel plate, resulting in a droplet-like, mottled coating film with exposed substrate. In Comparative Example 5, evaluation was impossible because the resin solidified and precipitated together with the tannin. In Comparative Example 6, phase separation was observed on the steel plate, and surface irregularities were seen. From the above, it was found that by including components A to E, a paint composition is provided that possesses uniformity, corrosion or rust prevention, and water resistance and durability. [Industrial applicability]

[0046] According to the present invention, a coating composition having uniformity, corrosion or rust prevention, and water resistance and durability can be obtained.

Claims

1. A metal coating composition comprising (A) styrene-acrylic acid copolymer resin, (B) solvent, (C) tannin, (D) anionic surfactant or nonionic surfactant, and (E) water, Component (B) comprises at least one selected from paraffinic solvents, mineral oil-based solvents, and aromatic solvents. The content of component (B) is 40 to 90% by mass on a basis of the total composition, the content of component (E) is 1 to 40% by mass on a basis of the total composition, and the content of component (B) is greater than the content of component (E). Paint composition for metals.

2. The composition according to claim 1, which is for rust prevention and / or rust replacement.

3. The composition according to claim 1, which is in the form of an emulsion.

4. (A) Styrene-acrylic acid copolymer resin in an amount of 3 to 50% by mass based on the total amount of the composition. (C) Tannins in an amount of 0.5 to 15% by mass based on the total amount of the composition, (D) Anionic surfactant or nonionic surfactant in an amount of 0.5 to 15% by mass based on the total amount of the composition. The composition according to claim 1, comprising:

5. A metal device, metal component, or metal structure comprising a coating film and / or black rust formed by the composition according to any one of claims 1 to 4.

6. A method for corrosion prevention, rust prevention, or rust replacement of metal equipment, metal members, or metal structures, comprising applying the composition according to any one of claims 1 to 4 to the surface of the metal equipment, metal members, or metal structures.

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