JP2023031144A - flash rust inhibitor - Google Patents

Abstract

To provide a flash rust inhibitor exhibiting an excellent flash rust preventing effect without containing a nitrite salt.SOLUTION: A flash rust inhibitor characterized by containing a salt (AB) of at least one carboxylic acid (A) selected from the group consisting of aliphatic dicarboxylic acids (A1) and carboxylic acids having a benzothiazole ring (A2), and at least one amine selected from the group consisting of N,N-dihydroxyalkylamine (B1) and (poly)alkylene polyamine (B2) is used.SELECTED DRAWING: None

Description

The present invention relates to flash rust inhibitors.

To provide an anti-corrosion water-based paint composition capable of preventing the occurrence of rust spots spreading on the coating surface and iron surface rust, which is called flash rust, even when directly applied to the iron surface. 100 parts by weight, 0.5 to 5 parts by weight of an antirust pigment, and 0.05 of one or more corrosion inhibitors selected from sodium nitrite, ammonium nitrite, calcium nitrite, sodium sulfite, sodium benzoate, and ammonium benzoate. 1.0 parts by weight of anti-corrosion water-based coating composition” has been proposed, and corrosion inhibitors include “sodium nitrite (NaNO ₂ ), ammonium nitrite (NH ₄ NO ₂ ), Calcium nitrite [Ca(NO ₂ ) ₂ ], sodium sulfite (Na ₂ SO ₃ ), sodium benzoate (C ₆ H ₅ COONa), ammonium benzoate (C ₆ H ₅ COONH ₄ )” has been proposed ( Patent document 1).

JP-A-8-73776

Nitrite such as “sodium nitrite (NaNO ₂ ), ammonium nitrite (NH ₄ NO ₂ ), calcium nitrite [Ca(NO ₂ ) ₂ ]” which is preferable in Patent Document 1 is the second The problem is that it reacts with class amines to produce nitrosamines, which are carcinogenic substances. Also, "sodium sulfite (Na ₂ SO ₃ ), sodium benzoate (C ₆ H ₅ COONa), and ammonium benzoate (C ₆ H ₅ COONH ₄ )" have a problem that the effect of preventing flash rust is weak.
An object of the present invention is to provide a flash rust preventive agent that does not contain nitrite and exhibits an excellent flash rust preventive effect.

The antiflash rust agent of the present invention is characterized by at least one carboxylic acid (A) selected from the group consisting of aliphatic dicarboxylic acids (A1) and carboxylic acids having a benzothiazole ring (A2),
The gist is that it contains a salt (AB) with at least one amine (B) selected from the group consisting of N,N-dihydroxyalkylamines (B1) and (poly)alkylenepolyamines (B2).

The main feature of the water-based paint of the present invention is that it contains the anti-flash rust agent, water and binder.

The anti-flash rust agent of the present invention exhibits an excellent anti-flash rust effect. In addition, since the antiflash rust agent of the present invention does not contain nitrites, it does not react with secondary amines and does not generate carcinogenic substances.

Since the water-based paint of the present invention contains the anti-flash rust agent, even if the water-based paint is applied directly to a metal surface, it does not cause flash rust, and a paint film with excellent appearance can be obtained. In addition, there is no concern about the generation of carcinogenic substances.

1 is a photograph taken when evaluating flash rust on the surface of a coating film prepared using the anti-flash rust agent of Example 1 in the section of the implementation. 1 is a photograph taken when evaluating flash rust on the surface of a coating film prepared using the anti-flash rust agent of Comparative Example 1 in the column of Examples. 1 is a photograph taken when evaluating flash rust on a (blank) coating surface prepared without an anti-flash rust agent in the Examples section.

As the aliphatic dicarboxylic acid (A1), any of straight-chain dicarboxylic acids, branched dicarboxylic acids and alicyclic dicarboxylic acids can be used, but straight-chain dicarboxylic acids are preferred.

The aliphatic dicarboxylic acid (A1) preferably has 4 to 14 carbon atoms, more preferably 6 to 12 carbon atoms, and particularly preferably 8 to 10 carbon atoms. Within this range, a more excellent flash last prevention effect is exhibited.

Aliphatic dicarboxylic acids (A1) are readily available on the market and include succinic acid (Nippon Shokubai Co., Ltd.), glutaric acid (Tokyo Chemical Industry Co., Ltd.), adipic acid (Sumitomo Chemical Co., Ltd.), pimelic acid (Tokyo Chemical Industry Co., Ltd. company), suberic acid (Tokyo Chemical Industry Co., Ltd.), azelaic acid (Tokyo Chemical Industry Co., Ltd.), sebacic acid (Toyokuni Oil Co., Ltd.), dodecanedioic acid (Ube Industries, Ltd.), tetradecanedioic acid (HighChem Co., Ltd.), Maleic acid (Mitsubishi Chemical Co., Ltd.), fumaric acid (Fuso Chemical Industries, Ltd.), itaconic acid (Tokyo Chemical Industry Co., Ltd.), and the like.

As the carboxylic acid having a benzothiazole ring (A2), any carboxylic acid having a benzothiazole ring can be used without limitation, but a carboxylic acid having a 2-benzothiazolylthio group is preferred. Preferred such carboxylic acids include 3-(2-benzothiazolylthio)propionic acid, (2-benzothiazolylthio)acetic acid, [6-(ethoxycarbonyl)-2-benzothiazolylthio]acetic acid, 2 -(Acetylamino)-3-(2-benzothiazolylthio)propionic acid, 4-methyl-2-benzothiazolylthioacetic acid, 6-amino-2-benzothiazolylthioacetic acid, 5-carboxy-2-benzo Thiazolylthioacetic acid, 3-(4-methyl-2-benzothiazolylthio)propionic acid, 3-(6-hydroxy-2-benzothiazolylthio)propionic acid, 2-benzothiazolylthioformic acid, 3-( 4,6-dimethyl-2-benzothiazolylthio)propionic acid, 2-(2-benzothiazolylthio)propionic acid, 2-(4-methyl-2-benzothiazolylthio)propionic acid, 5-(2 -benzothiazolylthio)valeric acid, 3-(2-benzothiazolylthio)valeric acid, 5-(4-methyl-2-benzothiazolylthio)valeric acid, 4-(2-benzothiazolylthio)butyric acid , 10-(2-benzothiazolylthio)undecanoic acid, 10-(4-methyl-2-benzothiazolylthio)undecanoic acid, 2-(2-benzothiazolylthio)benzoic acid, 2-(4-methyl -2-benzothiazolylthio)benzoic acid and 2-(5-carboxy-2-benzothiazolylthio)benzoic acid.

Part of the carboxylic acid (A) may be replaced with a carboxylic acid other than the aliphatic dicarboxylic acid (A1) and the carboxylic acid (A2) having a benzothiazole ring.

Other carboxylic acids include fatty acids with 3 to 12 carbon atoms (propanoic acid, hexanoic acid, heptanoic acid, decanoic acid, dodecanoic acid, etc.) and aromatic carboxylic acids with 7 to 11 carbon atoms (benzoic acid, naphthalenecarboxylic acid, etc.). ) and the like.

When part of the carboxylic acid (A) is replaced with another carboxylic acid, the content (% by weight) of the other carboxylic acid is 10 to 60 with respect to the weight of the carboxylic acid (A) and the other carboxylic acid. It is preferably 12-55, particularly preferably 15-52. Within this range, a more excellent flash last prevention effect is exhibited.

Examples of the N,N-dihydroxyalkylamine (B1) include diethanolamine, diisopropanolamine, N-methyldiethanolamine and N-butyldiethanolamine.

(Poly)alkylenepolyamines (B2) include ethylenediamine, piperazine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and triethylenediamine.
In addition, "(poly)alkylenepolyamine" means "alkylenepolyamine" or "polyalkylenepolyamine".

The equivalent ratio (A/B) between the number of equivalents of the carboxyl group and the number of equivalents of the amino group is preferably 1.4 to 0.7, more preferably 1.3 to 0.8, and particularly preferably 1.1 to 0.9. That is, the salt of carboxylic acid (A) and amine (B) may contain a completely neutralized salt and an unreacted functional group (carboxyl group or amino group) of carboxylic acid (A) or amine (B). . Within this range, a more excellent flash last prevention effect is exhibited.
The number of equivalents of the carboxyl group described above also includes the number of equivalents of the carboxyl group of another carboxylic acid when the other carboxylic acid is substituted.

The anti-flash rust agent of the present invention may optionally contain known additives (antifoaming agents, viscosity modifiers, wetting agents, rust inhibitors, etc., excluding carcinogenic substances and substances that induce carcinogenic substances). . The content of these is not limited as long as it does not inhibit the effects of the present invention, but is about 1 to 80% by weight based on the weight of the salt (AB) of carboxylic acid (A) and amine (B). .

The anti-flash rust agent of the present invention is not limited to a production method as long as the salt (AB) of the carboxylic acid (A) and the amine (B) is contained, but from the viewpoint of production efficiency, the carboxylic acid ( A neutralization reaction between A) and the amine (B) is preferably carried out. The neutralization reaction may be carried out by heating or cooling, and from the viewpoint of production efficiency, neutralization is preferably carried out at 25 to 65°C. When a known additive is included as necessary, it is preferable to add and mix after the neutralization reaction.

Examples of aqueous solvents include water and organic solvents that are easily soluble in water (methanol, ethanol, isopropyl alcohol, acetone, methyl ethyl ketone, ethylene glycol, diethylene glycol, tetrahydrofuran, etc.).

The antiflash rust agent of the present invention can be used as a solution or dispersion in an aqueous solvent, and can also be used in a solid form (powdery, granular, etc.) that does not contain an aqueous solvent.

Since the antiflashlast agent of the present invention exhibits an excellent antiflashlast effect, it is suitable as an antiflashlast agent for water-based paints.

The water-based paint of the present invention preferably contains the anti-flash rust agent, water and binder.
As the binder, those used for water-based coatings can be used, and vinyl acetate resins, acrylic resins, styrene resins, epoxy resins, halogenated olefin resins, urethane resins, silicone resins and fluorine atom-containing silicone resins can be used.

When the anti-flash rust agent of the present invention is applied to a water-based paint, the content (% by weight) can be appropriately determined depending on the application of the paint, but is preferably about 0.1 to 20 based on the weight of the binder. It is more preferably about 0.2 to 10, and particularly preferably about 0.3 to 5.

Hereinafter, unless otherwise specified, parts means parts by weight and % means % by weight.
<Example 1>
Water 219 parts, aliphatic dicarboxylic acid (a11: succinic acid, Nippon Shokubai Co., Ltd.) 118 parts (1 mol part) and N,N-dihydroxyalkylamine (b11: diethanolamine, Mitsui Chemicals, Inc.) 210 parts (2 mol parts) ) was heated to 60° C. with stirring, stirring was continued at this temperature for an additional 2 hours, then cooled with stirring to about 25° C., and the anti-flash rust agent of the present invention (a11b11; equivalence ratio (A /B) 1, water content 40%).

<Example 2>
Water 275 parts, aliphatic dicarboxylic acid (a12: sebacic acid, Toyokuni Oil Co., Ltd.) 202 parts (1 mol part) and N,N-dihydroxyalkylamine (b11: diethanolamine, Mitsui Chemicals, Inc.) 210 parts (2 mol parts) ) was heated with stirring to 60° C., stirring was continued at this temperature for an additional 2 hours, then cooled with stirring to about 25° C., and the anti-flash rust agent of the present invention (a12b11; equivalence ratio (A /B) 1, water content 40%).

<Example 3>
Water 332 parts, aliphatic dicarboxylic acid (a13: tetradecanedioic acid, Tokyo Chemical Industry Co., Ltd.) 232 parts (0.9 mol part) and N,N-dihydroxyalkylamine (b12: diisopropanolamine, Tokyo Chemical Industry Co., Ltd. ) was heated with stirring to 60° C., stirring was continued at this temperature for an additional 2 hours, and then cooled with stirring to about 25° C. to give the anti-flash rust agent of the present invention. (a13b12; equivalent ratio (A/B) 0.9, water content 40%).

<Example 4>
Water 326 parts, aliphatic dicarboxylic acid (a12: sebacic acid, Toyokuni Oil Co., Ltd.) 222 parts (1.1 mol part) and N,N-dihydroxyalkylamine (b12: diisopropanolamine, Tokyo Chemical Industry Co., Ltd.) 266 (2 molar parts) were heated to 60° C. with stirring, stirring was continued at this temperature for an additional 2 hours, and then cooled to about 25° C. with stirring to give the flash rust inhibitor of the present invention (a12b12). Equivalence ratio (A/B) of 1.1, water content of 40%).

<Example 5>
Water 181 parts, aliphatic dicarboxylic acid (a12: sebacic acid, Toyokuni Oil Co., Ltd.) 202 parts (1 mol part) and (poly) alkylenepolyamine (b21: diethylenetriamine, Tosoh Corporation) 69 parts (0.67 mol part) was heated to 60° C. with stirring, stirring was continued at this temperature for an additional 2 hours, then cooled to about 25° C. with stirring, and the anti-flash rust agent of the present invention (a12b21; equivalence ratio (A/ B) 1, water content 40%) was obtained.

<Example 6>
220 parts of water, a carboxylic acid having a benzothiazole ring (a21: (2-benzothiazolylthio) acetic acid, Sanshin Chemical Industry Co., Ltd.) 225 parts (1 molar part) and N,N-dihydroxyalkylamine (b11: diethanolamine , Mitsui Chemicals, Inc.) was heated to 60° C. while stirring, and the stirring was continued at this temperature for 2 hours, and then cooled to about 25° C. while stirring. of flash rust inhibitor (a21b11; equivalence ratio (A/B) 1, water content 40%).

<Example 7>
230 parts of water, a carboxylic acid having a benzothiazole ring (a21: (2-benzothiazolylthio) acetic acid, Sanshin Chemical Industry Co., Ltd.) 225 parts (1 molar part) and N,N-dihydroxyalkylamine (b13: N -Methyldiethanolamine, Tokyo Kasei Kogyo Co., Ltd.) 119 parts (1 mol part) was heated to 60°C with stirring, and the stirring was continued at this temperature for an additional 2 hours, and then cooled to about 25°C while stirring. Thus, a flash rust inhibitor of the present invention (a21b13; equivalence ratio (A/B): 1, water content: 40%) was obtained.

<Example 8>
230 parts of water, a carboxylic acid having a benzothiazole ring (a22: (2-benzothiazolylthio) propionic acid, Sanshin Chemical Industry Co., Ltd.) 239 parts (1 molar part) and N,N-dihydroxyalkylamine (b11: Diethanolamine, Mitsui Chemicals, Inc.) 105 parts (1 mol part) was heated to 60° C. with stirring, and the stirring was continued at this temperature for 2 hours. An inventive flash rust inhibitor (a22b11; equivalence ratio (A/B) of 1, water content of 40%) was obtained.

<Example 9>
Water 361 parts, aliphatic dicarboxylic acid (a12: sebacic acid, Toyokuni Oil Co., Ltd.) 202 parts (1 mol part), other carboxylic acid (benzoic acid, manufactured by Emerald Kalama Chemical) 211 parts (1.7 mol part) And (poly) alkylene polyamine (b21: diethylene triamine, Tosoh Corporation) 128 parts (1.2 mol part) was heated to 60 ° C. with stirring, and the stirring was continued at this temperature for 2 hours, and then stirred. The mixture was cooled to about 25° C. while cooling to obtain a flash rust preventive agent of the present invention (a12'b21; equivalence ratio (A/B): 1, water content: 40%).

<Example 10>
Water 211 parts, aliphatic dicarboxylic acid (a12: sebacic acid, Toyokuni Oil Co., Ltd.) 202 parts (1 mol part), other carboxylic acid (benzoic acid, manufactured by Emerald Kalama Chemical) 36 parts (0.3 mol part) And (poly) alkylene polyamine (b21: diethylene triamine, Tosoh Corporation) 79 parts (0.8 mol part) was heated to 60 ° C. with stirring, and the stirring was continued at this temperature for 2 hours, and then stirred. The mixture was cooled to about 25° C. while cooling to obtain a flash rust preventive agent of the present invention (a12'b21; equivalence ratio (A/B): 1, water content: 40%).

<Comparative example>
Sodium benzoate (Fuji Film Wako Pure Chemical Industries, Ltd.) was used as the flash rust inhibitor (H) based on the description of Example 6 of Patent Document 1 (JP-A-8-73776).

Aqueous paints for evaluation were prepared and evaluated for anti-flash rust property as follows.

(1) Preparation of emulsion base paint With the raw material composition shown in the table below, using an Excel auto homogenizer (Nippon Seiki Co., Ltd., model ED) equipped with an impeller type blade, grind and let down to prepare an emulsion base paint. Obtained.

*1 Thickener, San Nopco Co., Ltd. *2 Dispersant, San Nopco Co., Ltd. *3 Calcium carbonate, Takehara Chemical Industry Co., Ltd.,
*4 Titanium oxide, Ishihara Sangyo Co., Ltd., and “Tipaque” are registered trademarks of the same company.
*5 Acrylic binder, resin concentration 50%, BASF, "ACRONAL" is a registered trademark of BASF Societas Europe. *6 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, KH Neochem Co., Ltd., "Kyowanol" is a registered trademark of KH Neochem Co., Ltd.
*7 Thickener, San Nopco Co., Ltd.

(2) Preparation of water-based paint To 100 parts of the emulsion base paint, add 0.84 parts of any of the anti-flash rust agents prepared in Examples (water content 40%) or anti-flash rust agents prepared in Comparative Examples (H: water content 0%) was added, and stirred and mixed for 5 minutes at 15-25°C and 2000 rpm in an Excel auto homogenizer equipped with an impeller-type blade to obtain a water-based paint for evaluation (1-10, H). A water-based paint for evaluation (blank) was obtained in the same manner as described above, except that no anti-flash rust agent was added.

(3) Evaluation of flash last prevention property Using an applicator, the emulsion paint for evaluation is applied to a structural steel plate SS400 (TP Giken Co., Ltd., 15 cm × 7 cm × 1.6 cm, JIS G3101: 2015) to a wet film thickness of 100 μm. and allowed to stand for 1 hour in a constant temperature and humidity bath (temperature 50° C., relative humidity 90%). After drying, flash rust on the surface of the coating film was visually evaluated.

○：フラッシュラスト無し
×：フラッシュラストが部分的に有り
××：フラッシュラストが全体的に有り

○: No flash last ×: Partial flash last XX: Overall flash last

The water-based paint using the anti-flash rust agent of the present invention was superior in anti-flash rust properties to those using the anti-flash rust agent for comparison.

Claims (6)

At least one carboxylic acid (A) selected from the group consisting of aliphatic dicarboxylic acids (A1) and carboxylic acids (A2) having a benzothiazole ring;
Flash characterized by containing a salt (AB) with at least one amine (B) selected from the group consisting of N,N-dihydroxyalkylamines (B1) and (poly)alkylenepolyamines (B2) rust inhibitor. 2. The antiflash rust agent according to claim 1, wherein the aliphatic dicarboxylic acid (A1) is a linear dicarboxylic acid. 3. The flash rust inhibitor according to claim 1, wherein the aliphatic dicarboxylic acid (A1) has 4 to 14 carbon atoms. 4. The flash rust preventive agent according to any one of claims 1 to 3, wherein the carboxylic acid (A2) having a benzothiazole ring is a carboxylic acid having a 2-benzothiazolylthio group. 5. The anti-flash rust agent according to claim 1, wherein the equivalent ratio (A/B) of the number of equivalents of carboxyl groups and the number of equivalents of amino groups is from 1.4 to 0.7. A water-based paint comprising the antiflash rust agent according to any one of claims 1 to 5, water and a binder.

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