JP2000219981A - Antifreezing solution composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antifreezing solution composition capable of suppressing the blacking of aluminum or an aluminum alloy used in a cooling system of an internal combustion engine. SOLUTION: This antifreezing solution composition consists essentially of glycol containing a corrosion suppressing agent, contains a dicarboxylic acid or a tricarboxylic acid and/or their salts having a 10-20C alkyl group as the end group and contains no amines, nitrites, phosphates, borates and silicates. The blacking of aluminum and the aluminum alloy used in the cooling system of the internal combustion engine is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifreeze composition for use in a cooling fluid for an internal combustion engine of an automobile or the like, and more particularly to a method for suppressing blackening of aluminum and aluminum alloy used in a cooling system of an internal combustion engine. It relates to an effective antifreeze composition.

[0002]

2. Description of the Related Art Cooling systems for internal combustion engines such as automobile engines include aluminum, aluminum alloys, cast iron, steel, and the like.
Various metals such as brass, solder, or copper are used, and cooling water as a cooling medium flows through the system.

[0003] The cooling water contains an antifreeze containing alcohols or glycols having a freezing point lowering effect, such as ethylene glycol, in order to suppress freezing in winter. However, alcohols and glycols have an action of corroding metals, and if only ethylene glycols are used, metals in the cooling system will be corroded. Corrosion of the metal in the cooling system can cause the engine to overheat and cause a failure.

[0004] For this reason, antifreeze generally contains a corrosion inhibitor for protecting metals from corrosion, in addition to alcohols and glycols. As a corrosion inhibitor, triethanolamine salts, nitrites, phosphates, borates, silicates, and the like are appropriately used in combination, and various compositions have been reported.

[0005] For example, JP-A-2-120388 discloses an antifreeze composition containing alkenyl succinic acid having 4 to 16 carbon atoms, triazole, borate and silicate.

[0006] However, the above-mentioned corrosion inhibitors such as amine salts have some problems.

For example, when an amine salt coexists with a nitrite, it produces nitrosamine having carcinogenicity.

[0008] Phosphates cause eutrophication of seawater, lakes and rivers, and adversely affect living organisms.

Further, the borate corrodes the aluminum alloy (see Japanese Patent Publication No. 49-5509), which is not preferable for a recent internal combustion engine in which the aluminum alloy is frequently used.

[0010] Silicates have poor stability in antifreeze,
When heated, the pH is changed, or when other salts coexist, the gel is easily formed and the corrosion inhibiting ability is reduced.

To solve this problem of corrosion inhibitors, US Pat. No. 4,588,513 uses sebacic acid as an aliphatic dicarboxylic acid and uses amine salts, nitrites,
An antifreeze composition is disclosed that is free of chromate, phosphate and borate.

JP-A-4-117481 discloses an antifreeze composition containing sebacic acid and p-tertbutylbenzoic acid and containing no amine salt, nitrite, phosphate, borate or silicate. Has been disclosed.

[0013]

When aluminum and an aluminum alloy are immersed in an antifreeze containing no phosphate or silicate, a black oxide film is formed on the metal surface, and the metal turns black. Since blackening occurs very quickly, it is hard to imagine that corrosion has progressed simultaneously with blackening, but in general it is thought that blackened aluminum is also undergoing corrosion, and because it has poor appearance, Not liked by users.

No. 4,588,513 described above.
Japanese Patent Application Laid-Open No. HEI 4-117481 does not contain phosphates or silicates having an effect of preventing blackening of aluminum. Blackening problem occurs.

In order to prevent blackening of aluminum, JP-A-9-263976 discloses an antifreeze composition comprising an ionic lithium compound as a blackening inhibitor for aluminum or aluminum alloy.

In view of such circumstances, an object of the present invention is to
An object of the present invention is to provide a different antifreeze composition capable of preventing blackening of aluminum or an aluminum alloy without containing amine salts, nitrites, phosphates, borates and silicates.

[0017]

The antifreeze composition of the present invention comprises a glycol containing a corrosion inhibitor as a main component and a dicarboxylic acid or tricarboxylic acid having an alkyl group having 10 to 20 carbon atoms at a terminal and / or Characterized by being free from amines, nitrites, phosphates, borates and silicates.

Such a configuration of the present invention is different from a conventional antifreeze solution, and can effectively prevent blackening of aluminum and aluminum alloy.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the antifreeze composition of the present invention contains a glycol containing a corrosion inhibitor as a main component, and has a dicarboxylic acid or tricarboxylic acid having an alkyl group having 10 to 20 carbon atoms at the terminal and / or Or a salt thereof, and is free from an amine, a nitrite, a phosphate, a borate, and a silicate.

Here, "having an alkyl group having 10 to 20 carbon atoms at the terminal" refers to a structure in which an alkyl group having 10 to 20 carbon atoms is attached to, for example, a terminal portion of dicarboxylic acid.

The corrosion inhibitor is preferably selected from at least one of nitrates, molybdates, triazoles, thiazoles, benzoates, aliphatic monobasic acids, and aliphatic dibasic acids.

The glycols are preferably selected from one, two or more of ethylene glycol, propylene glycol and diethylene glycol.

The dicarboxylic acid having a terminal alkyl group having 10 to 20 carbon atoms is preferably at least one of decylsuccinic acid, dodecylsuccinic acid, tetradecylsuccinic acid, hexadecylsuccinic acid, and octadecylsuccinic acid. Selected. Hexadecyl succinic acid or octadecyl succinic acid is particularly preferred.

The tricarboxylic acid having an alkyl group having 10 to 20 carbon atoms at the terminal is preferably at least one of decylenoic acid, dodecylenoic acid, tetradecylenoic acid, hexadecylenoic acid, and octadecylenoic acid. Selected. Hexadesilic acid or octadecylenoic acid is particularly preferred.

In the antifreeze composition of the present invention, a colorant, an antifoaming agent, a bittering agent and the like can be selectively used in combination.

Next, the operation of the components of the present invention will be described.

The glycols, which are the main components of the antifreeze composition of the present invention, have an effect of lowering the freezing point of the antifreeze.

Corrosion inhibitors prevent corrosion of aluminum, aluminum alloys, cast iron, steel, brass, solder, or copper.

A dicarboxylic acid or tricarboxylic acid having an alkyl group having 10 to 20 carbon atoms at a terminal and / or a salt thereof prevents blackening of an aluminum casting.

Here, it is important that the dicarboxylic acid or dicarboxylic acid or tricarboxylic acid used in the present invention and / or salts thereof have an alkyl group having 10 to 20 carbon atoms at the terminal. The dicarboxylic acid or tricarboxylic acid and / or salts thereof used in the present invention can prevent blackening of aluminum and aluminum alloy much better than before by having such a structure. is there.

JP-A-4-59885 discloses a coolant composition containing an alkali metal salt of an aliphatic dibasic acid salt having 20 to 22 carbon atoms. The aliphatic diacid used here is disclosed. The salts are carbon-centered, unlike the dicarboxylic acids of the invention, which are carbon-terminated. For this reason, as will be apparent from the examples described later,
The coolant composition of No. 9885 does not have the ability to prevent blackening of aluminum and aluminum alloys as in the present invention.

[0032]

EXAMPLES Examples and comparative examples will be specifically described below. Note that the present embodiment shows a typical example of the present invention, and the present invention is not limited thereto.

The antifreeze compositions according to the present invention were prepared in Examples 1 to
4 and the composition for comparison with this example was Comparative Example 1
These configurations are shown in Table 1 below.

Embodiment 1

As shown in Table 1, the terminal has 10 to 2 carbon atoms.
Hexadecylsuccinic acid having an alkyl group of 0 (0.0
1% by weight), sebacic acid (3.7% by weight), and benzotriazole (0.3% by weight) are mixed with ethylene glycol, and the pH value of a 30% by weight aqueous solution of the antifreeze composition is adjusted. Potassium hydroxide (48% by weight aqueous solution) required to achieve 7.8 was added. Also, trace amounts of dyes and defoamers were added. Ethylene glycol was used in an amount necessary to make the total amount 100% by weight.

Embodiment 2

Example 1 is the same as Example 1 except that octadecyl succinic acid having an alkyl group having 10 to 20 carbon atoms at the terminal (0.01% by weight) was used instead of hexadecyl succinic acid.

Embodiment 3

Example 1 is the same as Example 1 except that hexadecyl succinic acid having a terminal alkyl group having 10 to 20 carbon atoms (0.01% by weight) was used instead of hexadecyl succinic acid.

Comparative Example 1

The same as Example 1 except that hexadecyl succinic acid was not included.

Comparative Example 2

Example 1 except that dodecanoic acid (0.01% by weight) was used instead of hexadecylsuccinic acid.
Is the same as

Comparative Example 3

Example 1 is the same as Example 1 except that octylsuccinic acid (0.01% by weight) was used instead of hexadecylsuccinic acid.

Comparative Example 4

Instead of hexadecylsuccinic acid, 7,12-dimethyl-7,11-octadecanediethylene-1, an aliphatic dibasic acid having 20 to 22 carbon atoms, disclosed in JP-A-4-59885. Same as Example 1 except that 18-dicarboxylic acid (0.01% by weight) was used.

[0048]

[Table 1] Antifreeze compositions of Examples and Comparative Examples * Sodium hydroxide was used in an amount required to adjust the pH value of a 30% aqueous solution of the antifreeze composition to 7.8.

Next, tests performed on these examples and comparative examples will be described.

The blackening prevention ability of aluminum and aluminum alloys was evaluated by a metal corrosion test specified in JIS K2234 antifreeze.

In this test, the antifreeze composition was mixed with prepared water (chlorine ion, sulfate ion and carbonate
(Water containing 0 ppm), diluted to 30% by volume, 750 ml of the diluted solution was placed in a 1-liter flask, and a metal test piece composed of aluminum casting, cast iron, steel, brass, solder and copper was immersed in the diluted solution. After that, dry air 10
The mixture was heated at 88 ° C. for 336 hours while blowing at a rate of 0 ml / min. The ability to prevent blackening was measured by the change in appearance of the aluminum casting after this test.

The amount of change in mass of the metal test piece before and after heating the metal piece was evaluated as the metal corrosion inhibiting ability.

An antifreeze composition having an excellent ability to inhibit metal corrosion has a small change in mass, and an antifreeze composition having an inferior corrosion inhibition ability has a large change in mass because the metal is damaged by corrosion.

Table 2 shows the results of the metal corrosion test.

[0055]

[Table 2] Metal corrosion test results

From Table 2, the change in mass of the metal of Example 1 was
-0.05 to -0.01 mg / cm2, the mass change of the metal of Example 2 is-
0.04 to 0.00 mg / cm2, the mass change of the metal of Example 3 was -0.0
4 to -0.01 mg / cm2.
It can be seen that it has a metal corrosion inhibiting ability that sufficiently satisfies the standard value of SK 2234 antifreeze.

On the other hand, the mass change of the metal of Comparative Example 1 was -0.0
5 to -0.01 mg / cm2, the mass change of the metal of Comparative Example 2 was -0.13
~ 0.00mg / cm2, the mass change of the metal of Comparative Example 3 was -0.06 ~-
0.01 mg / cm2, the change in mass of the metal of Comparative Example 4 is -0.09 to -0.09.
01 mg / cm2, and Comparative Examples 1 to 4 are also JIS K2
It can be seen that it has a metal corrosion inhibiting ability which sufficiently satisfies the standard value of 234 antifreeze.

However, in Examples 1 to 3, there was no change in the appearance of the aluminum casting before and after heating, but in Comparative Examples 1 to
In each of the samples No. 4, the aluminum turned black after heating.

Hereinafter, the respective examples and comparative examples will be examined.

Example 1 is an antifreeze composition containing hexadecylsuccinic acid, which is a dicarboxylic acid having an alkyl group having 10 to 20 carbon atoms at the terminal, used in the present invention. In Example 1, there was no change in the appearance of the aluminum casting before and after heating.

On the other hand, Comparative Example 1 had the same structure as that of Example 1 except that hexadecylsuccinic acid was not contained, but the aluminum casting turned black after heating. This indicates that the dicarboxylic acid having an alkyl group having 10 to 20 carbon atoms at the terminal of the present invention has blackening preventing ability.

Comparative Example 2 contained dodecylic acid, but the aluminum casting turned black after heating. This is because dodecyl acid was monobasic, so its solubility in the diluent was low, and it was separated from the solution, so it was not possible to exert a sufficient blackening inhibitory effect on aluminum castings. Can be

In Comparative Example 3 containing octylsuccinic acid, the aluminum casting turned black after heating. This is considered to be because the alkyl group of octyl succinic acid is short (8 carbon atoms) and thus does not have sufficient blackening preventing ability on aluminum castings.

In Comparative Example 4, 7,12- aliphatic aliphatic acid having 20 to 22 carbon atoms disclosed in JP-A-4-59885 was used.
Contains dimethyl-7,11-octadecanediethylene-1,18-dicarboxylic acid. In Comparative Example 4, the aluminum casting turned black after heating because the 7,12-dimethyl-7,11-octadecanediethylene-1,18-dicarboxylic acid had an alkyl group at the center, so that the aluminum casting turned black enough. It is considered that there is no prevention ability.

From the above test results, antifreeze containing monobasic acid, octylsuccinic acid having less than 10 carbon atoms, or dicarboxylic acid having an alkyl group at the center has the ability to inhibit metal corrosion, but has a black corrosion resistance against aluminum. It is clear that it does not have the ability to inhibit the change.

The dicarboxylic acid or tricarboxylic acid having an alkyl group having 10 to 20 carbon atoms at the terminal of the present invention has both the ability to inhibit the corrosion of metals and the ability to inhibit blackening of aluminum.

[0067]

As described above, the antifreeze composition of the present invention containing a dicarboxylic acid or a tricarboxylic acid having an alkyl group having 10 to 20 carbon atoms at the end thereof can be used for an aluminum used in a cooling system of an internal combustion engine. And blackening of the aluminum alloy.

Although not shown in experiments, it has been confirmed that the antifreeze composition of the present invention improves the ability of aluminum casting to inhibit corrosion under cavitation.

Furthermore, since the antifreeze composition of the present invention does not contain amine salts and nitrites, it does not produce nitrosamines having carcinogenic properties.

Since the antifreeze composition of the present invention does not contain a borate, it does not impair the corrosion inhibiting ability of aluminum.

Further, since the antifreeze composition of the present invention does not contain a phosphate, it does not cause eutrophication even when it flows into seawater, lakes, river water, and the like.

Further, since the antifreeze composition of the present invention does not contain a silicate, it has excellent stability in the antifreeze, and can be used in gels even when heated, when the pH changes, or when other salts coexist. It does not form, and there is no problem of deterioration of the ability to inhibit corrosion due to gelation.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihisa Kurokawa 813 Yoshikawa, Shimizu-shi, Shizuoka Nippon Chemical Industry Co., Ltd. F-term (reference) 4K062 BA08 BA10 BB04 BB06 BB18 BB22 FA03 FA16

Claims (5)

[Claims] 1. An antifreeze composition comprising a glycol containing a corrosion inhibitor as a main component, comprising: 1) a dicarboxylic acid or a tricarboxylic acid having an alkyl group having 10 to 20 carbon atoms at a terminal, and / or a salt thereof; And 2) free of amines, nitrites, phosphates, borates and silicates. 2. The antifreeze composition according to claim 1, wherein the corrosion inhibitor is a nitrate, a molybdate, a triazole, a thiazole, a benzoate, an aliphatic monobasic acid, or an aliphatic dibasic acid. An antifreeze composition wherein at least one of the basic acids is selected. 3. The antifreeze composition according to claim 1, wherein the glycol is one of ethylene glycol, propylene glycol, and diethylene glycol.
An antifreeze composition, wherein one or more are selected. 4. The antifreeze composition according to claim 1, wherein the dicarboxylic acid is at least one of decylsuccinic acid, dodecylsuccinic acid, tetradecylsuccinic acid, hexadecylsuccinic acid, and octadecylsuccinic acid. The antifreeze composition of choice. 5. The antifreeze composition according to claim 1, wherein the tricarboxylic acid is decylenoic acid, dodecylenoic acid, tetradecylenoic acid, hexadecylenoic acid,
Or an antifreeze composition wherein at least one of octadecylic acid is selected.