JP2007269841A - 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 a modified silicone oil. The antifreeze liquid/cooling liquid composition comprises, preferably, the modified silicone oil and a fluorine compound. <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

  As a result of intensive research 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 inventors of the present invention have found that the modified silicone oil has It was found that the present invention 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 magnesium alloy, which contains a modified silicone oil.

  Since the antifreeze / coolant composition of the present invention contains a modified silicone oil, corrosion of magnesium or a magnesium alloy constituting the cooling system can be effectively suppressed.

  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 modified silicone oil.

  The modified silicone oil contained in the antifreeze / coolant composition of the present invention is resistant to corrosion of magnesium or magnesium alloy constituting the cooling system in the antifreeze / coolant circulating in the cooling system of an internal combustion engine such as an engine. There is a function to suppress effectively. Since the modified silicone oil also has a function of suppressing corrosion of aluminum or aluminum alloy, when the cooling system is made of aluminum or aluminum alloy, or the cooling system is made 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.

  Examples of modified silicone oils having such functions include amino groups, epoxy groups, carboxyl groups, carbinol groups, methacryl groups, mercapto groups, phenol groups, alkoxy groups, polyether groups, methylstyryl groups, alkyl groups, Mention may be made of silicone oil modified by introducing one or more organic groups selected from fatty acid ester groups and fluoroalkyl groups.

  Among the above-mentioned modified silicone oils, non-reactive modified silicone oils, particularly any one or two or more organic materials selected from polyether groups, methylstyryl groups, alkyl groups, higher fatty acid ester groups and fluoroalkyl groups. Silicone oil modified by introducing a group is preferable in that the corrosion inhibitory effect of magnesium or a magnesium alloy is remarkable, and the handleability and availability are excellent.

  The antifreeze / coolant composition of the present invention can also take a form in which a fluorine compound is used in combination with a modified silicone oil. The fluorine compound itself has a corrosion inhibiting effect on magnesium or magnesium alloy. However, when used in combination with the modified silicone oil, the corrosion inhibiting effect of magnesium or magnesium alloy is dramatically increased, and an excellent corrosion inhibiting effect surpassing the corrosion inhibiting effect of the modified silicone oil comes to be 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, hydrogen fluoride, potassium fluoride, sodium fluoride, ammonium fluoride, and lithium fluoride are preferable in that they are excellent in the corrosion inhibition effect of magnesium or magnesium alloy.

  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 modified silicone oil as a corrosion inhibitor for magnesium or 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 modified silicone oil in the antifreeze / coolant composition of the present invention is preferably in the range of 0.0001 to 20% by mass with respect to 100% by mass of the base. When the content of the modified silicone oil is less than this range, it is not possible to obtain a sufficient corrosion inhibiting effect on magnesium or a magnesium alloy, and when the content of the modified silicone oil is larger 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 modified silicone oil and the fluorine compound are used in combination, the content of the fluorine compound is 0.01 to 5% by mass relative to 100% by mass of the base. The range of is preferable. When the content of the fluorine compound is less than 0.01% by mass below this range, a synergistic effect with the modified silicone oil 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, brassylic 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 silicone oil A (H.P.) modified with ethylene glycol and ion-exchanged water as a base and introducing a polyether group into the side chain of the polysiloxane. Examples 1 and 2 containing L.B 11), Examples containing silicone oil B (HLB 12) modified by introducing polyether groups into the side chain of the polysiloxane in the base 3 to 5 were shown respectively. In addition, as a comparison, a comparative example consisting only of a base that does not contain a modified silicone in the base is shown. For each sample of Examples 1 to 5 and the comparative example, an immersion test and a metal corrosion test are performed, and whether there is any discoloration of the appearance. In addition, the mass change of each metal was 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、ベース中に変性シリコーンオイルを含む実施例１及び４では、変色は生じてはいるものの、いずれ中程度であった。また、変性シリコーンオイルとフッ化化合物の両成分を含む実施例２及び５については、いずれも変色はなかった。また、実施例２及び３の質量変化について見てみると、いずれも＋０．０８ｍｇ／ｃｍ²、＋０．８３ｍｇ／ｃｍ²と僅かな変化に止まっていた。これらの試験結果から、実施例に係るサンプルが、腐食抑制効果に優れていることが確認された。

As is apparent 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 the modified silicone oil contained in the base. In 1 and 4, although discoloration occurred, it was moderate. Moreover, about Example 2 and 5 containing both components of a modified silicone oil and a fluorinated compound, there was no discoloration. Also, looking at the mass change of Examples 2 and 3, both + 0.08 mg / cm ^2, had stopped a slight change + 0.83 mg / cm ^2. From these test results, it was confirmed that the samples according to the examples were excellent in the corrosion inhibition effect.

  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 (11)

  An antifreeze / coolant composition for magnesium or a magnesium alloy, comprising a modified silicone oil.   The antifreeze / coolant composition for magnesium or magnesium alloy according to claim 1, wherein the composition contains a fluorine compound together with the modified silicone oil.   The modified silicone oil is an amino group, epoxy group, carboxyl group, carbinol group, methacryl group, mercapto group, phenol group, alkoxy group, polyether group, methylstyryl group, alkyl group, higher fatty acid ester group and fluoroalkyl group. 3. Antifreeze / cooling for magnesium or magnesium alloy according to claim 1 or 2, wherein the silicone oil is modified by introducing one or more organic groups selected from among them. Liquid composition.   The antifreeze / coolant composition for magnesium or magnesium alloy according to any one of claims 1 to 3, wherein the modified silicone oil is a non-reactive modified silicone oil.   Non-reactive modified silicone oil was modified by introducing one or more organic groups selected from polyether groups, methylstyryl groups, alkyl groups, higher fatty acid ester groups and fluoroalkyl groups. 5. The antifreeze / coolant composition for magnesium or magnesium alloy according to claim 4, which is a silicone oil.   The fluorine compound is any one or more selected from hydrogen fluoride, potassium fluoride, sodium fluoride, ammonium fluoride, and lithium fluoride. The antifreeze / coolant composition for magnesium or magnesium alloy according to any one of the above.   The antifreeze / coolant for magnesium or magnesium alloy according to claim 1, which is based on one or a mixture of two or more selected from water, alcohols, glycols, and glycol ethers. Composition.   The antifreeze / coolant composition for magnesium or magnesium alloy according to any one of claims 1 to 7, wherein the content of the modified silicone oil is 0.0001 to 20% by mass relative to 100% by mass of the base. object.   The antifreeze / coolant composition for magnesium or magnesium alloy according to any one of claims 2 to 8, 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. 10. The antifreeze / coolant composition for magnesium or magnesium alloy according to any one of 9 above.   The antifreeze / coolant composition for magnesium or magnesium alloy according to any one of claims 1 to 10, comprising one or more selected from triazoles or thiazoles.