JP2007269831A - Antifreeze liquid/cooling liquid composition for magnesium or magnesium alloy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antifreeze liquid/cooling liquid composition suitably used for cooling system of internal combustion engine such as engine and capable of effectively suppressing corrosion of magnesium or magnesium alloy. <P>SOLUTION: The antifreeze liquid/cooling liquid composition comprises one or more kinds of compounds selected from an alkylsuccinic acid, an alkenylsuccinic acid and salts thereof. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an antifreeze / coolant composition for magnesium or magnesium alloy, which is excellent in the corrosion inhibition effect of magnesium or magnesium alloy constituting a cooling system of an internal combustion engine such as an engine.

  For example, metals such as aluminum, aluminum alloys, cast iron, steel, brass, solder, and copper are used for cooling systems of internal combustion engines such as engines. These metals are corroded by contact with water or air. For this reason, corrosion prevention of these metals was achieved by including a metal corrosion inhibitor in the antifreeze / coolant composition applied to the cooling system.

  In recent years, automobiles have been reduced in weight for the purpose of saving resources and energy. In this trend, the component materials that make up the engine cooling system have also been reviewed for the purpose of weight reduction. Magnesium or magnesium, which has the lightest specific gravity among practical metals and also has excellent recyclability. Alloys are in the limelight.

  However, magnesium or a magnesium alloy has the lowest standard electrode potential among practical metals, and it has been difficult to effectively suppress corrosion in an aqueous solution.

  Recently, compositions using compounds effective in preventing corrosion of magnesium or magnesium alloys have been proposed. For example, fluoride is known as a rust preventive for magnesium (see Non-Patent Document 1).

  Patent Document 1 proposes a cooling liquid composition including a composition obtained by adding a carboxylic acid to the fluoride or fluorocarboxylic acid (see Patent Document 1).

  In addition, a cooling liquid composition using carboxylic acid amide or sulfonic acid amide as a compound effective for preventing corrosion of magnesium or a magnesium alloy has been proposed (see Patent Document 2).

Although the coolant compositions containing these compounds all have a corrosion mitigating effect on magnesium, they are insufficient for application to cooling systems such as engines, and a composition having a higher corrosion inhibiting effect is desired. It was done.
SAE Technical Paper Series 850418 Special table 2002-527619 Special table 2004-506091

  The present inventors have conducted extensive research on an antifreeze / coolant composition having a sufficient corrosion-inhibiting effect to be applied to a cooling system such as an engine composed of magnesium or a magnesium alloy. It was found that succinic acid or a salt thereof was extremely effective for inhibiting corrosion of magnesium or a magnesium alloy, and the present invention was completed based on this finding.

  That is, an object of the present invention is to provide an antifreeze / coolant composition that is excellent in the corrosion inhibiting effect of magnesium or magnesium alloy constituting the cooling system.

  In order to achieve the above object, the gist of the present invention is an antifreeze / coolant composition for magnesium or a magnesium alloy, which contains alkyl succinic acid, alkenyl succinic acid, or a salt thereof.

  Since the antifreeze / coolant composition of the present invention contains oxalic acid or the like, it is possible to effectively suppress the corrosion of magnesium or magnesium alloy constituting the cooling system.

  Hereinafter, the antifreeze / coolant composition for magnesium or magnesium alloy of the present invention (hereinafter simply referred to as antifreeze / coolant composition) will be described in more detail. The antifreeze / coolant composition of the present invention is characterized by containing alkyl succinic acid, alkenyl succinic acid, or a salt thereof.

  Alkyl succinic acid, alkenyl succinic acid, or salts thereof (hereinafter referred to as oxalic acid or the like) include, for example, magnesium constituting the cooling system in an antifreeze / cooling liquid circulating in the cooling system of an internal combustion engine such as an engine. It works to effectively suppress the corrosion of magnesium alloys. In addition, oxalic acid has a function of suppressing the corrosion of aluminum, aluminum alloys, and iron-based metals, so the cooling system is configured to include aluminum, aluminum alloys, and iron-based metals in addition to magnesium or magnesium alloys. Even in this case, an excellent corrosion inhibitory effect is exhibited for these metals.

  Among the oxalic acid and the like, those having 4 to 24 carbon atoms have a remarkable effect of inhibiting corrosion of magnesium or a magnesium alloy, and are excellent in handleability and availability. That is, oxalic acid having more than 24 carbon atoms is not easily available, and the antifreeze / coolant composition is easily foamed.

  Preferred examples of the succinic acid include one or a mixture of two or more selected from octenyl succinic acid, decenyl succinic acid, dodecenyl succinic acid, octyl succinic acid, decyl succinic acid, and dodecyl succinic acid. These salts are preferably alkali metal salts.

  In addition, the antifreeze / coolant composition of the present invention can take a form in which a fluorine compound is used in combination with oxalic acid or the like. The fluorine compound itself has a corrosion inhibiting effect on magnesium or magnesium alloy. However, when used in combination with oxalic acid or the like, the corrosion inhibition effect of magnesium or magnesium alloy is dramatically increased, and an excellent corrosion inhibition effect surpassing the corrosion inhibition effect of oxalic acid or the like is exhibited.

  As the fluorine compound, hydrogen fluoride, potassium fluoride, sodium fluoride, ammonium fluoride, lithium fluoride, sodium fluorocarboxylate, potassium fluorocarboxylate, or the like can be used. Among the above fluorine compounds, any one or a mixture of two or more selected from hydrogen fluoride, potassium fluoride, sodium fluoride, ammonium fluoride, and lithium fluoride is effective in inhibiting corrosion of magnesium or a magnesium alloy. It is preferable at the point which is excellent in.

  For the base of the antifreeze / coolant composition of the present invention, one or a mixture of two or more selected from water, alcohols, glycols, and glycol ethers can be used.

  Examples of the alcohols include those composed of one or a mixture of two or more selected from methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, and octanol.

  Examples of glycols include one selected from ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,5-pentanediol, and hexylene glycol, or The thing which consists of 2 or more types of mixtures can be mentioned.

  Examples of glycol ethers include ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol monoethyl ether. Mention may be made of one or a mixture of two or more selected from ethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, and tetraethylene glycol monobutyl ether.

  The content of oxalic acid or the like is desirably in the range of 0.0001 to 20% by mass with respect to 100% by mass of the base. When the content of oxalic acid or the like is less than this range, a sufficient corrosion-inhibiting effect on magnesium or magnesium alloy cannot be obtained, and when the content of oxalic acid or the like is more than this range, it exceeds the range. This is because the effect of just the minute cannot be expected and it becomes uneconomical.

  In the antifreeze / coolant composition of the present invention, when the oxalic acid or the like and a fluorine compound are used in combination, the content of the fluorine compound is 0.01 to 5% by mass with respect to 100% by mass of the base. A range is preferred. When the content of the fluorine compound is less than 0.01% by mass below this range, a synergistic effect with oxalic acid or the like cannot be expected, and a sufficient corrosion inhibiting effect on magnesium or a magnesium alloy cannot be obtained. When the content of the fluorine compound is more than 5% by mass, an effect exceeding the range cannot be expected, which is uneconomical.

  The antifreeze / coolant composition according to the present invention includes an aromatic monobasic acid, an aromatic dibasic acid, an aliphatic monobasic acid, an aliphatic dibasic acid, and salts thereof. Alternatively, a mixture of two or more kinds can be included.

Aromatic monobasic acids and salts thereof include benzoic acids such as benzoic acid, nitrobenzoic acid and hydroxybenzoic acid, p-toluic acid, p-ethylbenzoic acid, p-propylbenzoic acid, p-isopropylbenzoic acid, alkyl benzoate such as p-tert-butylbenzoic acid, the general formula _{RO-C 6 H 4 -COOH (} R is C ₁ -C alkyl group ₅₎ alkoxy benzoic acid represented by the general formula R-C ₆ H ₄ Cinnamic acid, alkylcinnamic acid, alkoxycinnamic acid represented by —CH═COOH (R is a C _{1 to} C ₅ alkyl group or alkoxy group), or an alkali metal salt, ammonium salt or amine salt thereof. Can be mentioned. Among these, benzoic acid, p-toluic acid, and p-tertbutylbenzoic acid are excellent in the corrosion-preventing performance of aluminum-based or iron-based metals, and it is desirable that at least one of these be included.

  In addition, examples of the aromatic dibasic acid and salts thereof include phthalic acid, isophthalic acid, terephthalic acid, and alkali metal salts and ammonium salts thereof.

  As content of the said aromatic monobasic acid or aromatic dibasic acid, the range of 0.1-10 mass% is desirable. When the content of these aromatic monobasic acids or aromatic dibasic acids is less than 0.1% by mass, a sufficient corrosion prevention effect for aluminum-based or iron-based metals cannot be expected, and when the content is more than 10% by mass Is not economical because the effect exceeding 10% by mass cannot be obtained.

  Aliphatic monobasic acids and their salts include pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, 2-ethylhexanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, oleic acid, linoleic acid, linolenic acid , Ricinoleic acid, stearic acid and their alkali metal salts, ammonium salts and the like.

  Aliphatic dibasic acids and their salts include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, piperic acid, suberic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanedioic acid, brassic acid, And taptic acid, or alkali metal salts, amine salts and ammonium salts thereof. Among these, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid are more preferable from the viewpoint of excellent performance.

  The aliphatic monobasic acid, aliphatic dibasic acid and salts thereof are desirably contained in the range of 0.1 to 10% by mass. When the content of aliphatic monobasic acid, aliphatic dibasic acid and salts thereof is less than 0.1% by mass, sufficient corrosion prevention effect for aluminum-based or iron-based metal is not exhibited, and 10% by mass In the case of exceeding, there is no effect as much as exceeding and it becomes uneconomical.

  Further, the antifreeze / coolant composition according to the present invention may contain one or a mixture of two or more selected from triazoles and thiazoles. Specific examples of triazoles include benzotriazole, tolyltriazole, 4-phenyl-1,2,3-triazole, 2-naphthotriazole and 4-nitrobenzotriazole, among which benzotriazole and Tolyltriazole is preferred. Examples of thiazoles include benzothiazole and mercaptobenzothiazole.

  The addition of these triazoles or thiazoles can improve the corrosion prevention effect of copper-based metals such as brass and copper. The content of triazoles is preferably in the range of 0.01 to 1.0% by mass, and the content of thiazoles is preferably in the range of 0.01 to 1.0% by mass.

  In addition to the above components, the antifreeze / coolant composition according to the present invention may contain an antifoaming agent, a colorant, and a conventionally known corrosion inhibitor. Examples of conventionally known corrosion inhibitors include phosphoric acid or its salts, silicates, nitrates, nitrites, borates, molybdates, and amine salts, or a mixture of two or more. Can do.

  In addition, this invention is not limited to the following Example, It can implement freely by changing in the range described in the "Claims".

  In Table 1 below, as an example of a preferred composition, Example 1 was based on ethylene glycol and ion-exchanged water, and this base contained dodecenyl succinate and potassium fluoride, and octenyl succinate and fluoride in the base. Example 2 containing potassium and Example 3 containing octyl succinic acid and potassium fluoride in the base were shown, respectively. Table 1 also shows, for comparison, Comparative Example 1 containing benzoic acid in the base, Comparative Example 2 containing sebacic acid in the base, and Comparative Example 3 consisting only of the base containing no corrosion inhibitor. A metal corrosion test was performed on each of the samples of Examples 1 to 3 and Comparative Examples 1 to 3, and a change in mass of the test piece (magnesium alloy) was confirmed. The results are shown in Table 2.

  The metal corrosion test was performed in accordance with JIS K 2234 metal corrosive regulations, and a magnesium alloy (AZ91D) was used for this metal test piece.

表２から明らかなように、ベースのみからなる比較例３の場合、＋２．２８ｍｇ／ｃｍ²という質量変化があったのに対し、安息香酸やセバシン酸を添加した比較例１および２の質量変化は、それぞれ＋２．２３ｍｇ／ｃｍ²、＋１．９７ｍｇ／ｃｍ²という結果であった。これに対して、琥珀酸等を含む実施例１〜３についての各試験片の質量変化は、いずれも＋０．２７ｍｇ／ｃｍ²、＋０．２３ｍｇ／ｃｍ²、並びに０．４４ｍｇ／ｃｍ²と僅かな変化に止まっており腐食抑制効果に優れていることが確認された。

As is apparent from Table 2, in the case of Comparative Example 3 consisting of only the base, there was a mass change of +2.28 mg / cm ² , whereas in Comparative Examples 1 and 2 to which benzoic acid or sebacic acid was added, respectively + 2.23 mg / cm ^2, was a result of + 1.97mg / cm ^2. In contrast, the mass change of each specimen for Example 1-3 containing succinic acid and the like are all ^{+ 0.27mg / cm 2, + 0.23mg} / cm 2, and 0.44 mg / cm ² and slightly It was confirmed that the corrosion inhibition effect was excellent.

  The present invention is suitably used for a cooling system of an internal combustion engine such as an engine, in particular, a cooling system composed of magnesium and a magnesium alloy.

Claims (9)

  An antifreeze / coolant composition for magnesium or a magnesium alloy, comprising at least one selected from alkyl succinic acid, alkenyl succinic acid, and salts thereof.   The antifreeze / coolant composition for magnesium or magnesium alloy according to claim 1, comprising a fluorine compound together with at least one selected from alkyl succinic acid, alkenyl succinic acid, and salts thereof.   3. The antifreeze / coolant composition for magnesium or magnesium alloy according to claim 1, wherein the alkyl succinic acid, the alkenyl succinic acid, or a salt thereof has 4 to 24 carbon atoms.   The alkyl succinic acid or alkenyl succinic acid is one or a mixture of two or more selected from octenyl succinic acid, decenyl succinic acid, dodecenyl succinic acid, octyl succinic acid, decyl succinic acid, and dodecyl succinic acid The antifreeze / coolant composition for magnesium or magnesium alloy according to any one of claims 1 to 3.   The magnesium or magnesium alloy according to any one of claims 1 to 4, which is based on one or a mixture of two or more selected from water, alcohols, glycols, and glycol ethers. Antifreeze / coolant composition.   Magnesium according to any one of claims 1 to 5, wherein the content of alkyl succinic acid, alkenyl succinic acid, or a salt thereof is 0.0001 to 20% by mass relative to 100% by mass of the base. Or antifreeze / coolant composition for magnesium alloys.   The antifreeze / coolant composition for magnesium or magnesium alloy according to any one of claims 2 to 6, wherein the content of the fluorine compound is 0.01 to 5% by mass relative to 100% by mass of the base. .   It contains one or two or more selected from aromatic monobasic acids, aromatic dibasic acids, aliphatic monobasic acids, aliphatic dibasic acids and salts thereof. 8. The antifreeze / coolant composition for magnesium or magnesium alloy according to any one of 7 above.   The antifreeze / coolant composition for magnesium or magnesium alloy according to any one of claims 1 to 8, comprising one or more selected from triazoles or thiazoles.