JP4554001B2 - Rust-proof paint and rust-proof metal material - Google Patents

Description

【００２１】
２．イオン源
【表２】

【００２２】
２．塗膜の物性
（１）耐食製：
得られた樹脂塗装鋼板について６ｍｍ押し出したエリクセン加工材を作成し、ＪＩＳ２３７１にしたがって塩水噴霧試験を実施し、錆が１％発生するまでの時間により評価した。
【００２３】
（２）塗膜密着性：
得られた樹脂塗装鋼板にカッターナイフで縦横それぞれ１ｍｍ間隔に１０本の線の線を入れ、テープ剥離試験を行い、樹脂塗膜の残存桝目数にて評価した。
【００２４】
（３）耐水塗膜密着性
得られた樹脂塗装鋼板にカッターナイフで縦横それぞれ１ｍｍ間隔に１０本の線の線を入れ、沸騰水に一時間浸漬したのち、塗膜の剥離の様子を３段階で評価した。
【００２５】
（４）塗膜硬度
鉛筆硬度法により評価した。
【００２６】
（５）塗膜のブロッキング性
樹脂塗装鋼板を２枚、塗装面が内側で重なるように合わせ、２５ｍｍ幅のヒートシーラーで両面から７０℃で１分加熱し引き剥がす際の抵抗を３段階で評価した。
【００２７】
［製造例１］（水性分散液の製造）
内容量５００ｍＬのオートクレーブに、水２４０ｇと共重合体▲１▼を８０ｇ、アンモニア水を１１．７ｇ及び酸化亜鉛を１．８ｇ仕込み、圧力０．５ＭＰａ温度１５０℃で１時間撹拌したのち冷却して取り出した。平均粒子径は２６ｎｍ、粘度は３７０ｍＰａ・ｓであった。
【００２８】
［製造例２］（同上）
製造例１において、酸化亜鉛の代わりに、水酸化マグネシウム２．６ｇが用いられた。平均粒子径は５０ｎｍ、粘度は４００ｍＰａ・ｓであった。
【００２９】
［製造例３］（同上）
内容量５００ｍＬのオートクレーブに、水２４０ｇと共重合体▲２▼を８０ｇ、アンモニア水を９．８ｇ、水酸化カリウム１．６ｇ及び酸化亜鉛を１．５ｇ仕込み、圧力０．５ＭＰａ温度１５０℃で１時間撹拌したのち冷却して取り出した。平均粒子径は３６ｎｍ、粘度は２００ｍＰａ・ｓであった。
【００３０】
［製造例４］（同上）
製造例３において酸化亜鉛の代わりに水酸化マグネシウム２．２ｇが用いられた。平均粒子径は３９ｎｍ、粘度は２００ｍＰａ・ｓであった。
【００３１】
［製造例５］（同上）
内容量５００ｍＬのオートクレーブに、水２４０ｇと共重合体▲３▼を８０ｇ、水酸化カリウム５．２ｇ及び酸化亜鉛を４．６ｇ仕込み、圧力０．５ＭＰａ温度１５０℃で１時間撹拌したのち冷却して取り出した。平均粒子径は２９ｎｍ、粘度は３５０ｍＰａ・ｓであった。
【００３２】
［製造例６］（同上）
製造例５において、酸化亜鉛の代わりに水酸化マグネシウム３．３ｇが用いられた。平均粒子径は３８ｎｍ、粘度は２４０ｍＰａ・ｓであった。
【００３３】
［製造例７］（同上）
内容量５００ｍＬのオートクレーブに、水２４０ｇと共重合体▲３▼を８０ｇ、水酸化ナトリウム３．７ｇを仕込み、圧力０．５ＭＰａ温度１５０℃で１時間撹拌したのち冷却して取り出した。平均粒子径は１９ｎｍ、粘度は１８０ｍＰａ・ｓであった。
【００３４】
［製造例８］（同上）
内容量５００ｍＬのオートクレーブに、水２４０ｇと共重合体▲１▼を８０ｇ、アンモニア水９．８ｇを仕込み、圧力０．５ＭＰａ温度１５０℃で１時間撹拌したのち冷却して取り出した。平均粒子径は７０ｎｍ、粘度は３００ｍＰａ・ｓであった。
【００３５】
［製造例９］（同上）
製造例８においてアンモニア水の代わりに水酸化カリウム１１．２ｇが用いられた。平均粒子径は１４ｎｍ、粘度は３００ｍＰａ・ｓであった。
【００３６】
［製造例１０］（同上）
内容量５００ｍＬのオートクレーブに、水２４０ｇと共重合体▲１▼を８０ｇ及び酸化亜鉛を５．４ｇ仕込み、圧力０．５ＭＰａ温度１５０℃で１時間撹拌したのち冷却して取り出した。平均粒子径は５８０ｎｍ、粘度は６３７０ｍＰａ・ｓであった。
【００３７】
各製造例で得られた水性分散液の、ベースポリマーとイオン源は下記表３のとおりである。
【表３】

【００３８】
［実施例１，３，４］
製造例１，３，４の水分散液をそれぞれ固形分１０％に希釈し、亜鉛メッキ鋼板を浸し、塗布した後、１５０℃で１０分間加熱乾燥して塗膜を形成させた。室温に戻したのち２４時間室温でエージングし、樹脂塗装鋼板の塗膜の物性試験を行った。結果を表４に示す。表中、水分散液の番号は製造例番号である。
【００３９】
［比較例１〜６］
製造例５〜１０の水分散液をそれぞれ固形分１０％に希釈し、亜鉛メッキ鋼板を浸し、塗布した後、１５０℃で１０分間加熱乾燥して塗膜を形成させた。室温に戻したのち２４時間室温でエージングし、樹脂塗装鋼板の塗膜の物性試験を行った。結果を表４に示す。
【００４０】
【表４】

【００４１】
【発明の効果】
本発明によれば、耐熱水性、耐摩耗性、塗膜密着性に優れた塗布膜を形成することができる防錆塗料を提供することができる。かくして得られる被覆金属材料は、前記特性を有する他、耐蝕性、耐変色性に優れており、各種家庭電気機器材料、建材、蛇籠等の土木資材、車両、船舶等の用途に利用することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rust preventive paint capable of forming a coating film excellent in wear resistance, corrosion resistance, and adhesion to a metal material, and a metal material coated with the rust preventive paint. In particular, the present invention relates to a rust preventive paint that exhibits excellent adhesion and rust preventive properties to plated steel such as galvanized steel and zinc alloy plated steel.
[0002]
[Prior art]
Conventionally, a metal material mainly composed of iron, steel, or the like has been plated with tin or zinc, or further subjected to chromate treatment or phosphoric acid treatment. These treatments improve rust prevention to some extent, but problems such as the surface being easily soiled and blackening have been left, and various proposals for solving the problem have been made. A typical example is a method in which an aqueous dispersion of a carboxyl group-containing olefin polymer typified by an ethylene / acrylic acid copolymer containing colloidal silica is applied to a metal material to form a rust preventive coating. is there.
[0003]
For example, according to Japanese Examined Patent Publication No. 5-54823, a resin-coated steel sheet excellent in paintability and corrosion resistance, in which a rust preventive paint obtained by adding colloidal silica to an aqueous dispersion of an ethylene / unsaturated carboxylic acid copolymer is applied. Has been proposed. Further, according to JP-A-6-246229, an aqueous solution of an ethylene / unsaturated carboxylic acid copolymer having a neutralization degree of 60 to 80% on a steel plate subjected to chromate-treated zinc or zinc alloy plating. A blackening-resistant coated steel sheet coated with a dispersion has been proposed. The aqueous dispersions of ethylene / unsaturated carboxylic acid copolymers used in these proposals have been widely used which are exclusively dispersed with sodium ions or ammonium ions.
[0004]
However, the coating film obtained from the aqueous dispersion dispersed with ammonium ions not only has a low softening temperature and poor heat resistance, but also has insufficient wear resistance, and from an aqueous dispersion dispersed with sodium ions. The obtained coating film was not only insufficient in water resistance, but also insufficient in adhesion to galvanization.
[0005]
However, JP-A-6-246229 discloses one example of the use of an aqueous dispersion containing zinc ions, and JP-A-9-192601 also discloses zinc coating on the surface of an aluminum-based metal. Illustrated in two examples using aqueous dispersions containing ions. However, in the former example, an aqueous dispersion in which a melt of zinc ionomer is dispersed in water using a homomixer is used. However, such an aqueous dispersion has poor stability and stable quality. Not only is it difficult to produce a coating film, but it is also difficult to reduce the dispersed particle size, so that there is a drawback that pinholes are likely to occur in the coating film. In the latter example, the same drawback is likely to occur.
[0006]
[Problems to be solved by the invention]
Therefore, the present inventors have studied to improve the above-mentioned drawbacks in a conventional antirust coating using an aqueous dispersion of an ethylene / unsaturated carboxylic acid copolymer. As a result, it has been found that such disadvantages can be improved when an aqueous dispersion composed of specific mixed ions is used. Accordingly, an object of the present invention is to provide a novel anticorrosive paint and a metal coated with such a paint, which are excellent in hot water resistance and wear resistance, and can form a coating film exhibiting good adhesion to a plated steel sheet. To provide materials.
[0007]
[Means for Solving the Problems]
The present invention is a rust preventive paint comprising an aqueous dispersion of an ethylene / unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 10 to 30% by weight, based on the carboxyl group of the copolymer, 10-60 mole% of polyvalent metal ions, to anticorrosive coatings which is characterized by containing a mixture of ions of 50 to 120 mol% of ammonium ion or an ammonium ion and an alkali metal ion. The present invention also relates to a metal material coated with such a rust preventive paint.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
As the raw material of the aqueous dispersion of the present invention, an ethylene copolymer having an unsaturated carboxylic acid content of 10 to 30% by weight is used. In particular, considering the dispersibility and the heat resistance of the coating film, the unsaturated carboxylic acid content Is preferably 15 to 25% by weight of an ethylene / unsaturated carboxylic acid copolymer. When a copolymer having an unsaturated carboxylic acid content of less than 10% by weight is used, it is difficult to obtain a stable aqueous dispersion. When a copolymer having a content exceeding 30% by weight is used, Although it is dispersed, it immediately aggregates and an aqueous dispersion excellent in storage stability cannot be obtained. Here, the unsaturated carboxylic acid is acrylic acid, methacrylic acid, maleic anhydride, etc., particularly acrylic acid or methacrylic acid is preferable, and acrylic acid is particularly preferable.
[0009]
Such a copolymer may also be obtained by copolymerizing other monomers in addition to ethylene and unsaturated carboxylic acid. Such other monomers include propylene, 1-butene, isobutene, vinyl acetate, methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, methyl acrylate, unsaturated esters, one Examples thereof include carbon oxide. When such a monomer containing a large amount of other monomers is used, the melting point of the coating film is generally lowered and the heat resistance is impaired, and therefore usually, such a monomer is not contained or contained. However, the content is desirably 20% by weight or less, and particularly preferably 10% by weight or less.
[0010]
As the raw material ethylene / unsaturated carboxylic acid copolymer, the melt flow rate at 190 ° C. and a load of 2160 g is taken into consideration in view of ease of production of the aqueous dispersion, dispersion stability, physical properties of the coating obtained from the aqueous dispersion, etc. Is 1 to 2000 g / 10 min, preferably 10 to 1000 g / 10 min. Such a copolymer can be obtained by copolymerizing a predetermined monomer mixture at a temperature of 200 to 300 ° C. and a pressure of about 100 to 300 MPa in the presence of a polymerization initiator. Also, from the market, products having the product names Nukurel (Mitsui / DuPont Polychemical Co., Ltd.) and Primacor (Dow Co., Ltd.) are available.
[0011]
In the present invention, such an aqueous dispersion of a copolymer is used, and the aqueous dispersion contains 10 to 60 mol%, preferably 15 to 45 mol% of polyvalent metal ions based on the carboxyl group. Further, ammonium ions or an ion mixture of ammonium ions and alkali metal ions is contained in an amount corresponding to 50 to 120 mol%, preferably 60 to 90 mol%. That is, if the content of the polyvalent metal ions is less than the above range, the heat resistance, wear resistance, adhesion to the plated steel, etc. of the coating film will be insufficient, and when the content exceeds the above range, The dispersed particle size becomes too large, and it becomes difficult to obtain a uniform coating film. The appropriate content of ammonium ions or an ion mixture of this and alkali metal ions varies slightly depending on the type of ionic species and copolymer, but if the content is too small, a stable aqueous dispersion can be produced. Is not easy, or the dispersed particle size becomes large, and it becomes difficult to form a uniform coating film.
[0012]
Here, the polyvalent metal is an alkaline earth metal such as magnesium, calcium or barium, zinc or aluminum, and a divalent metal such as alkaline earth metal or zinc is particularly preferable. In the present invention, in order to obtain a coating film having excellent water resistance, ammonium ion is an essential component, but it can also be used as an ion mixture of this and an alkali metal. Examples of the alkali metal include lithium, sodium, potassium, cesium, rubidium, and the use of sodium or potassium is particularly preferable.
[0013]
The aqueous dispersion suitable for the anticorrosive paint of the present invention has an average particle size of dispersed particles of 1 to 1000 nm, preferably 5 to 100 nm, and a solid content concentration of 5 to 50% by weight, preferably 10%. It is in the range of ˜40% by weight. That is, by having such properties, it is possible to obtain a rust-preventing paint having an appropriate solution viscosity, stable and excellent in the uniformity of the coating film. Such an aqueous dispersion also has a viscosity of 5 to 1000 mPa · s, preferably 10 to 500 mPa · s, and a pH of 9.5 to 12, preferably 10 to 11.5.
[0014]
The method for producing an aqueous dispersion having a small particle size as described above is described in detail in Japanese Patent Application No. 10-66770 according to the applicant's proposal.
[0015]
Various additives can be arbitrarily mixed in the anticorrosive paint of the present invention. Examples of such additives include antioxidants, ultraviolet absorbers, light stabilizers, plasticizers, pigments, dyes, antiblocking agents, crosslinking agents, crosslinking aids, inorganic fillers such as silica, and the like. Can do. Such additives can also be added in the form of an aqueous dispersion. These blending amounts are arbitrary, but based on the solid content of the aqueous dispersion, for example, 40% by weight or less for colloidal silica, 30% by weight or less for wax, and 1% by weight or less for crosslinking agent. can do.
[0016]
Such a rust preventive paint can be applied to various metal materials having various shapes. Particularly suitable metal materials are various types of plated steel, such as steel plated with zinc, aluminum, magnesium, copper, tin, chromium, nickel, etc., or steel plated with two or more of these alloys. It can be illustrated. Such plated steel may also be untreated, or may have been subjected to surface treatment such as chromate treatment or phosphoric acid treatment or colored coating. Examples of other applicable metal materials include aluminum, an aluminum alloy, and a titanium alloy. Such a metal material may have any shape such as a plate, a tube, or a wire.
[0017]
In order to apply the anticorrosive paint of the present invention to such a metal material, a conventionally known method can be employed. After applying the anticorrosive paint, a dry film can be formed by heating as necessary. Thus, it is possible to form a rust-preventing film having excellent characteristics made of an ethylene / unsaturated carboxylic acid copolymer ionomer having a polyvalent metal ion as an ion source. The coating thickness of such a rust preventive paint is preferably about 1 to 20 μm, particularly about 1 to 10 μm.
[0018]
The anticorrosive paint of the present invention can be used as an outermost layer as it is, but a resin layer can be further provided thereon. For example, when used outdoors for a long time, such as gabion, a resin layer subjected to a weathering stability formulation can be formed by extrusion coating or the like.
[0019]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
The composition of the ethylene / unsaturated carboxylic acid copolymer used as the raw material for the aqueous dispersion used in the Examples, physical properties, the type of ion source, and the physical properties of the obtained coating film were evaluated as follows. The three-level evaluation of physical properties is as follows.
1: Good 2: Slightly bad 3: Bad
1. Ethylene / unsaturated carboxylic acid copolymer The following three types of copolymers were used.
[Table 1]

[0021]
2. Ion source [Table 2]

[0022]
2. Physical properties of coating film (1) Corrosion-resistant:
An Erichsen processed material extruded 6 mm from the obtained resin-coated steel sheet was prepared, a salt spray test was performed according to JIS 2371, and the time until rust was generated by 1% was evaluated.
[0023]
(2) Coating film adhesion:
The obtained resin-coated steel sheet was put into 10 lines at 1 mm intervals in the vertical and horizontal directions with a cutter knife, a tape peeling test was performed, and the number of residual cells in the resin coating film was evaluated.
[0024]
(3) Adhesion of water-resistant coating film The resulting resin-coated steel sheet is inserted into 10 lines at 1 mm intervals in both vertical and horizontal directions with a cutter knife and immersed in boiling water for 1 hour, and then the coating film is peeled in three stages. It was evaluated with.
[0025]
(4) Coating film hardness It evaluated by the pencil hardness method.
[0026]
(5) Coating Two blocking resin-coated steel sheets, aligned so that the painted surfaces overlap on the inside, and evaluated the resistance when peeling off by heating at 70 ° C for 1 minute from both sides with a 25mm wide heat sealer did.
[0027]
[Production Example 1] (Production of aqueous dispersion)
An autoclave with an internal volume of 500 mL was charged with 240 g of water, 80 g of copolymer (1), 11.7 g of aqueous ammonia and 1.8 g of zinc oxide, stirred at a pressure of 0.5 MPa and a temperature of 150 ° C. for 1 hour, and then cooled. I took it out. The average particle diameter was 26 nm, and the viscosity was 370 mPa · s.
[0028]
[Production Example 2] (Same as above)
In Production Example 1, 2.6 g of magnesium hydroxide was used instead of zinc oxide. The average particle size was 50 nm, and the viscosity was 400 mPa · s.
[0029]
[Production Example 3] (Same as above)
An autoclave having an internal volume of 500 mL was charged with 240 g of water and 80 g of copolymer (2), 9.8 g of aqueous ammonia, 1.6 g of potassium hydroxide and 1.5 g of zinc oxide, and a pressure of 0.5 MPa at a temperature of 150 ° C. After stirring for a time, it was cooled and taken out. The average particle size was 36 nm, and the viscosity was 200 mPa · s.
[0030]
[Production Example 4] (Same as above)
In Production Example 3, 2.2 g of magnesium hydroxide was used instead of zinc oxide. The average particle size was 39 nm and the viscosity was 200 mPa · s.
[0031]
[Production Example 5] (Same as above)
An autoclave with an internal volume of 500 mL was charged with 240 g of water and 80 g of copolymer (3), 5.2 g of potassium hydroxide and 4.6 g of zinc oxide, stirred at a pressure of 0.5 MPa and a temperature of 150 ° C. for 1 hour, and then cooled. I took it out. The average particle size was 29 nm, and the viscosity was 350 mPa · s.
[0032]
[Production Example 6] (Same as above)
In Production Example 5, 3.3 g of magnesium hydroxide was used instead of zinc oxide. The average particle diameter was 38 nm, and the viscosity was 240 mPa · s.
[0033]
[Production Example 7] (Same as above)
An autoclave having an internal volume of 500 mL was charged with 240 g of water, 80 g of copolymer (3) and 3.7 g of sodium hydroxide, stirred at a pressure of 0.5 MPa and a temperature of 150 ° C. for 1 hour, cooled and taken out. The average particle size was 19 nm and the viscosity was 180 mPa · s.
[0034]
[Production Example 8] (Same as above)
An autoclave having an internal volume of 500 mL was charged with 240 g of water, 80 g of copolymer (1) and 9.8 g of aqueous ammonia, stirred at a pressure of 0.5 MPa and a temperature of 150 ° C. for 1 hour, then cooled and taken out. The average particle size was 70 nm, and the viscosity was 300 mPa · s.
[0035]
[Production Example 9] (Same as above)
In Production Example 8, 11.2 g of potassium hydroxide was used instead of aqueous ammonia. The average particle size was 14 nm and the viscosity was 300 mPa · s.
[0036]
[Production Example 10] (Same as above)
An autoclave having an internal volume of 500 mL was charged with 240 g of water, 80 g of copolymer (1) and 5.4 g of zinc oxide, stirred at a pressure of 0.5 MPa and a temperature of 150 ° C. for 1 hour, cooled and taken out. The average particle diameter was 580 nm, and the viscosity was 6370 mPa · s.
[0037]
The base polymer and ion source of the aqueous dispersion obtained in each production example are shown in Table 3 below.
[Table 3]

[0038]
[Examples 1 , 3 and 4]
The aqueous dispersions of Production Examples 1 , 3, and 4 were each diluted to a solid content of 10%, dipped and coated with a galvanized steel sheet, and then heated and dried at 150 ° C. for 10 minutes to form a coating film. After returning to room temperature, it aged at room temperature for 24 hours, and the physical property test of the coating film of the resin coated steel plate was conducted. The results are shown in Table 4. In the table, the number of the aqueous dispersion is the production example number.
[0039]
[Comparative Examples 1 to 6 ]
Each of the aqueous dispersions of Production Examples 5 to 10 was diluted to a solid content of 10%, dipped and coated with a galvanized steel sheet, and then heated and dried at 150 ° C. for 10 minutes to form a coating film. After returning to room temperature, it aged at room temperature for 24 hours, and the physical property test of the coating film of the resin coated steel plate was conducted. The results are shown in Table 4.
[0040]
[Table 4]

[0041]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the rust preventive coating material which can form the coating film excellent in hot water resistance, abrasion resistance, and coating-film adhesiveness can be provided. The coated metal material thus obtained has the above-mentioned properties, and is excellent in corrosion resistance and discoloration resistance, and can be used for various household electrical equipment materials, construction materials, civil engineering materials such as gabions, vehicles, ships and the like. it can.

Claims (4)

An antirust paint comprising an aqueous dispersion of an ethylene / unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 10 to 30% by weight, based on the carboxyl group of the copolymer, 10 to 60 mol % of polyvalent metal ions and, anticorrosive coating, characterized by containing a mixture of ions of 50 to 120 mol% of ammonium ion or an ammonium ion and an alkali metal ion. The rust preventive paint according to claim 1, which is used for plated steel. A metal material which has been rust-proofed with the rust-proof paint according to claim 1. The metal material according to claim 3, which is a plated steel.