JP5096685B2 - Antifreeze / coolant composition for magnesium or magnesium alloy - Google Patents

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

  As a result of intensive studies on the 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, the present inventors have conducted at least one in the molecule. The present inventors have found that a surfactant having one fluorine atom is extremely effective for inhibiting corrosion of magnesium or a magnesium alloy, and completed the present invention 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 a surfactant having at least one fluorine atom in the molecule.

  Since the antifreeze / coolant composition of the present invention contains a surfactant having at least one fluorine atom in the molecule, it can effectively inhibit the corrosion of magnesium or magnesium alloy constituting the cooling system. it can.

  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 a surfactant having at least one fluorine atom in the molecule.

  The surfactant contained in the antifreeze / coolant composition of the present invention refers to a surfactant having at least one fluorine atom in the molecule, and the surfactant includes, for example, cooling of an internal combustion engine such as an engine. In the antifreeze / coolant that circulates in the system, there is a function of effectively suppressing corrosion of magnesium or magnesium alloy constituting the cooling system. Further, since the surfactant also has a function of suppressing corrosion of aluminum or aluminum alloy, when the cooling system is composed of aluminum or aluminum alloy, or the cooling system is composed of magnesium or magnesium alloy and aluminum or aluminum alloy. Even if it is constituted by these, an excellent corrosion inhibitory effect for these metals will be exhibited.

  Among the above surfactants, those having a perfluoroalkyl group as a hydrophobic group have a remarkable effect of inhibiting corrosion of magnesium or a magnesium alloy, and are excellent in handleability and availability.

  Preferred examples of such surfactants include sulfonate, carboxylate, dicarboxylate, phosphonate, phosphate ester, sulfonated lysine potassium salt, quaternary ammonium salt, sulfonamide, and acrylate. A polymer, polyoxyethylene ether, betaine, etc. can be mentioned.

  Further, the antifreeze / coolant composition of the present invention may take a form in which a fluoride is used in combination with the surfactant. Fluoride itself has the corrosion inhibiting effect of magnesium or magnesium alloy. However, when used in combination with a surfactant, the corrosion inhibitory effect of magnesium or a magnesium alloy is remarkably increased, and an excellent corrosion inhibitory effect surpassing the corrosion inhibitory effect of the surfactant is exhibited.

  As the fluoride, hydrogen fluoride, potassium fluoride, sodium fluoride, ammonium fluoride, lithium fluoride, or the like can be used.

  In addition, the antifreeze / coolant composition of the present invention includes, for example, water, alcohols, glycols, and glycol ethers as a base containing the above-described surfactant as a corrosion inhibitor for magnesium or a magnesium alloy. One or a mixture of two or more selected may be mentioned.

  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 the surfactant in the antifreeze / coolant composition of the present invention is within a range of 0.0001 to 20% by mass with respect to 100% by mass of the base in order to ensure a sufficient corrosion inhibiting effect on magnesium or a magnesium alloy. Is desirable. When the surfactant content is less than this range, sufficient corrosion inhibition effect on magnesium or magnesium alloy cannot be obtained, and when the surfactant content is higher than this range, the range is exceeded. 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 surfactant and the fluoride are used in combination, the fluoride content is 0.01 to 5% by mass with respect to 100% by mass of the base. The range of is preferable. When the content of fluoride is less than 0.01% by mass below this range, a synergistic effect with the surfactant cannot be expected, and a sufficient corrosion inhibiting effect on magnesium or a magnesium alloy cannot be obtained. When the content of fluoride 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, 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".

  Table 1 below shows, as an example of a preferred composition, a surfactant A based on ethylene glycol and ion-exchanged water, and comprising a perfluoroalkyl group / hydrophilic group / lipophilic group-containing oligomer. Examples 1 and 2, Examples 3 and 4 containing a surfactant B made of perfluorobutyl sulfonate in the base, and, as a comparison, a comparative example consisting only of a base containing no surfactant in the base In each of the samples of Examples 1 to 4 and the comparative example, the immersion test and the metal corrosion test were performed, and the presence / absence of discoloration in appearance and the mass change of each metal were confirmed. The results of the immersion test are shown in Table 2, and the results of the metal corrosion test are shown in Table 3.

  In the immersion test, the temperature of each sample is set to 100 ° C., and a test piece made of a magnesium alloy (AZ91D) is immersed in this sample for 24 hours to check whether the surface of the test piece after immersion is blackened. I went there. When corrosion occurs, magnesium hydroxide is generated on the surface of the test piece, and the surface of the test piece changes to black.

  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及び表３から明らかなように、ベースのみからなる比較例の場合、黒変し、＋２．２８ｍｇ／ｃｍ²という質量変化があったのに対し、ベース中に界面活性剤を含む実施例１〜３では、いずれも変色無し、或いは変色が生じてはいるものの、その程度は中度軽度であり、実施例２及び４の例では、質量変化も＋０．１５ｍｇ／ｃｍ²または０．８０ｍｇ／ｃｍ²という結果であり、試験片の腐食が抑制されたことが確認された。

As is clear from Tables 2 and 3, in the case of the comparative example consisting of only the base, it turned black and there was a mass change of +2.28 mg / cm ² , whereas an example including a surfactant in the base 1 to 3 had no discoloration or discoloration, but the degree thereof was moderately mild. In the examples of Examples 2 and 4, the mass change was also +0.15 mg / cm ² or 0.80 mg. It was a result of / cm ² , and it was confirmed that corrosion of the test piece was suppressed.

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 (7)

An antifreeze / coolant composition for magnesium or a magnesium alloy, characterized by containing a fluoride together with a surfactant having at least one fluorine atom in the molecule,
The surfactant comprises one or more selected from sulfonates, carboxylates, dicarboxylates, and phosphonates having a perfluoroalkyl group as a hydrophobic group,
Magnesium or magnesium alloy, wherein the fluoride is any one or more selected from hydrogen fluoride, potassium fluoride, sodium fluoride, ammonium fluoride, and lithium fluoride Antifreeze / coolant composition. The antifreeze / coolant composition for magnesium or magnesium alloy according to claim 1, wherein the hydrophobic group of the surfactant is perfluorobutyl sulfonate .   The magnesium or magnesium alloy according to any one of claims 1 to 2, which is based on one or a mixture of two or more selected from water, alcohols, glycols, and glycol ethers. Antifreeze / coolant composition.   The antifreeze / coolant composition for magnesium or magnesium alloy according to any one of claims 1 to 3, wherein the content of the surfactant is 0.0001 to 20% by mass relative to 100% by mass of the base. object.   Content of the said fluoride is 0.01-5 mass% with respect to 100 mass% of bases, The antifreeze / coolant composition for magnesium or magnesium alloys in any one of Claims 1-4 characterized by the above-mentioned. object.   It contains one or two or more selected from aromatic monobasic acids, aromatic dibasic acids, aliphatic monobasic acids, aliphatic dibasic acids and salts thereof. 6. The antifreeze / coolant composition for magnesium or magnesium alloy according to any one of 5 above.   The antifreeze / coolant composition for magnesium or magnesium alloy according to any one of claims 1 to 6, comprising one or more selected from triazoles or thiazoles.