JPS6120632B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel water-soluble rust inhibitor composition. Metals generally corrode and rust when they come into contact with water, air, or corrosive substances. For this reason, various metal corrosion inhibitors and metal rust preventive agents have been used heretofore. Functionally, these rust preventives can be roughly divided into water-soluble rust preventives, which are used by dissolving or dispersing in water, and oil-soluble rust preventives, which are used by dissolving or dispersing in oil-based media, such as mineral oil. . Furthermore, when classified structurally, they can be divided into inorganic rust preventives such as chromates, nitrites, and phosphates, and organic rust preventives such as various amines, carboxylates, and sulfonates. However, conventional rust preventive agents have a low rust prevention effect.
It is not completely satisfactory in terms of economy, usage, and other aspects, and there are many problems in use. Furthermore, the use of inorganic rust preventives has been regulated in recent years due to pollution and safety issues. For example, chromate is highly toxic, nitrite is carcinogenic, and phosphate has been pointed out to cause eutrophication of rivers, lakes, and marshes. On the other hand, since organic rust preventives are difficult to dissolve in water, they are generally inferior to inorganic rust preventives in their rust prevention effects, but among them, amines, which are effective, have a bad odor and are disliked due to skin irritation. There are many things. Furthermore, conventional water-soluble rust inhibitors are significantly affected by the quality of the water in which they are used; in general, they exhibit a considerable rust-preventing effect in water, but their rust-preventing power is insufficient in the atmosphere, and rust is likely to occur. . The present invention solves one of the drawbacks of conventional water-soluble rust preventives, which is the lack of rust preventive power in the atmosphere, and provides a water-soluble rust preventive composition that exhibits outstanding rust preventive effects through synergistic action. The purpose is to provide The water-soluble rust inhibitor of the present invention comprises a) lanolin fatty acid diethanolamide, b) N- _C10 to _C20 alkyl-ω-aminocarboxylic acid, a water-soluble salt thereof, and
a) at least one compound selected from the group consisting of water-soluble salts of _C1 - _C5 alkylbenzoic acids;
and b) in a weight ratio of 3:1 to 1:3. It is well known that lanolin, lanolin fatty acids obtained by saponifying lanolin, and their derivatives have antirust effects due to their structural characteristics. do not have. However, lanolin fatty acid diethanolamide alone does not have a sufficient rust preventive effect, but among the water-soluble organic rust preventive agents that have been recognized to have a rust preventive effect, N-alkyl whose alkyl is C ₁₀ to C ₂₀ If at least one of -ω-aminocarboxylic acid, its water-soluble salt, or alkylbenzoic acid's water-soluble salt is blended, it will strongly adsorb to the metal surface or form a strong adsorbent film. A water-soluble rust preventive agent is obtained which enhances the rust preventive power of conventional water-soluble rust preventive agents in the atmosphere, and at the same time has excellent rust preventive effects due to the synergistic action of both components. Lanolin fatty acid is a fatty acid obtained by saponifying and refining lanolin, and has the following composition (according to EVTruter, J.Soc.Cosm.Chem. (1962)). Normal fatty acids C ₁₀ to C ₃₂ approximately 7% Iso fatty acids C ₁₀ to _{C 32} approximately 23% Anteiso fatty acids C ₉ to _{C 31} approximately 30% Hydroxy fatty acids approximately 35% Other fatty acids approximately 5% Lanolin fatty acid diethanolamide is, for example, lanolin fatty acid and It can be easily produced by dehydrating diethanolamine at 170 to 180°C for 150 minutes while blowing nitrogen gas to give an acid value of 10 or less. The amide has two types, a 1:2 molar type and a 1:1 molar type, in which the molar ratio of lanolin fatty acid to diethanolamine is 1:2, and both can be used in the rust preventive agent of the present invention. However, from the viewpoint of both water solubility and antirust effect, a 1:2 molar type amide is more preferable. The b) component to be added to the above lanolin fatty acid diethanolamide has the general formula RNH
There is an N-alkyl-ω-aminocarboxylic acid represented by (CH ₂ ) _o COOH (wherein R is a C ₁₀ to C ₂₀ alkyl group) or a water-soluble salt thereof. Examples of the parent ω-aminocarboxylic acid include glycine, β-alanine, and γ-aminobutyric acid, with β-alanine, that is, β-aminopropionic acid being particularly preferred. Alkyl groups include lauryl, myristyl, coconut alkyl, tallow alkyl, etc. C _10
-C20 alkyl is mentioned, and if _C9 or less, the antirust effect is low, and if _C21 or more, water solubility decreases, so both are not preferred. Examples of its water-soluble salts include alkali metal salts, diethanolamine salts, diisopropanolamine salts, triisopropanolamine salts, and the like, among which diethanolamine salts are most preferred. In the present invention, as component b), instead of the above N-alkyl-ω-aminocarboxylic acid or a water-soluble salt thereof, or in combination with it, the general formula Water-soluble salts of alkylbenzoic acids (wherein R is _C1 - _C5 alkyl and M is an alkali metal salt or ammonium) can be used. Particularly preferred are water-soluble salts of alkylbenzoic acids having an alkyl group in the para position. Examples include sodium para-ethylbenzoate, ammonium para-isopropylbenzoate, potassium para-tert-butylbenzoate, and the like. Here, alkylbenzoic acids whose alkyl groups are _C6 or higher are not preferred from the viewpoint of water solubility. The mixing ratio of component a) and component b) is in the range of 3:1 to 1:3 in weight ratio of a) to b). When component a) exceeds this range, the water solubility decreases, and when component b) exceeds this range, the antirust effect decreases, so both are not preferred. A blending ratio of 1:1 to 1:2 is particularly preferred from the viewpoint of both water solubility and rust prevention effect. The water-soluble rust inhibitor of the present invention can be prepared as a 30-50% aqueous solution and diluted by adding it to water at the time of use so that the total concentration of active ingredients is 0.1-5.0% by weight. If necessary, antifoaming agents such as silicone-based, span-based, and sorbitan ester-based defoaming agents may be added. In addition, the water-soluble rust preventive agent of the present invention can be used not only for temporary rust prevention of steel materials and metal work processing such as cutting and grinding, but also for water-based anticorrosion paint, adhesive rust prevention tape, rust prevention paper, and peelable Demonstrates outstanding rust prevention effect when used on plastics, etc. Examples are shown below. The lanolin fatty acid diethanolamide used was of the 1:2 molar type. Example 1 Part 1 It has the composition listed in Table 1, and the concentration of the active ingredient
A cast iron plate (gray cast iron F-1, 50 x 100 x 3
mm) is fully immersed, its lower part is exposed to the liquid and its upper part is exposed to the air. At room temperature, blow air with an air pump for 8 hours and let it stand for 16 hours, one cycle, and repeat 4 cycles. The rusting status was observed for each cycle, and the results shown in the table were obtained. (However, the composition is shown in weight ratio.)

[Table] Part 2 Having the composition listed in Table 2 and the concentration of active ingredients
A steel plate (SPCC-B, 30 x 80 x 1 mm), which has been polished, degreased, and washed in a conventional manner, is immersed in a 0.3% aqueous solution. The state of rusting at room temperature was observed over time, and the results shown in Table 2 were obtained. (However, the composition is shown in weight ratio.)

[Table] Part 3 Weigh out 2 g of cast iron cuttings (gray cast iron F-1) in a shear dish, and onto this weigh 2 ml of an aqueous solution having the composition listed in Table 3 and having an active ingredient concentration of 1.0% with a pipette. do. The rusting situation was observed at room temperature, and the results shown in Table 3 were obtained. (However, the composition is shown in weight ratio.)

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[Table] Example 2 According to Parts 1, 2, and 3 of Example 1, the compositions listed in Tables 4, 5, and 6 were tested, and the results shown in each table were obtained. (However, the composition is shown in weight ratio.)

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Claims (1)

[Claims] 1 a) lanolin fatty acid diethanolamide;
b) at least one compound selected from the group consisting of N- _C10 to _C20 alkyl-ω-aminocarboxylic acids, water-soluble salts thereof, and water-soluble salts of _C1 to _C5 alkylbenzoic acids; ) to b) weight ratio is 3:
A water-soluble rust preventive agent characterized in that it is contained in a ratio of 1 to 1:3. 2. The water-soluble rust preventive agent according to claim 1, wherein the lanolin fatty acid diethanolamide is an amide in the form of 1 mole of lanolin fatty acid to 2 moles of diethanolamine. 3. The total concentration of the active ingredients in a) and b) is
The water-soluble rust inhibitor according to claim 1, which is added to water in an amount of 0.1 to 5.0% by weight. 4. The water-soluble rust inhibitor according to claim 1, wherein the ω-aminocarboxylic acid is β-aminopropionic acid. 5. The water-soluble rust inhibitor according to claim 1, wherein the alkylbenzoic acid is para- _C1 to _C5 alkylbenzoic acid.