CA2307621A1 - Cooling composition for use with magnesium materials - Google Patents
Cooling composition for use with magnesium materials Download PDFInfo
- Publication number
- CA2307621A1 CA2307621A1 CA002307621A CA2307621A CA2307621A1 CA 2307621 A1 CA2307621 A1 CA 2307621A1 CA 002307621 A CA002307621 A CA 002307621A CA 2307621 A CA2307621 A CA 2307621A CA 2307621 A1 CA2307621 A1 CA 2307621A1
- Authority
- CA
- Canada
- Prior art keywords
- use according
- cooling liquid
- water
- cooling
- acid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
- C09K5/20—Antifreeze additives therefor, e.g. for radiator liquids
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
- C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
- C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
Abstract
The invention relates to a cooling liquid referring to the total composition comprised of a) 0.005 to 0.5 wt. % tolyltriazole, b) 0.005 to 0.5 wt. %
benzotriazole, c) 0.005 to 10 wt. % of one or more corrosion inhibitors selected from branched aliphatic carboxylic acid with 6 to 11 C-atoms and from alkanolamine phosphates, d) 70 to 99.985 wt. % of a water soluble liquid alcohol with a boiling point above 100 ~C at normal pressure and water, alkalis and/or additional active substances as a remainder to total 100 wt. %.
The inventive cooling liquid is utilized for cooling components made of magnesium and or magnesium alloys.
benzotriazole, c) 0.005 to 10 wt. % of one or more corrosion inhibitors selected from branched aliphatic carboxylic acid with 6 to 11 C-atoms and from alkanolamine phosphates, d) 70 to 99.985 wt. % of a water soluble liquid alcohol with a boiling point above 100 ~C at normal pressure and water, alkalis and/or additional active substances as a remainder to total 100 wt. %.
The inventive cooling liquid is utilized for cooling components made of magnesium and or magnesium alloys.
Description
~
_v "Cooling liquid for use in units made of magnesium"
This invention relates to an alcohol-based cooling or heating medium. It may be used in cooling or heating systems, such as air-conditioning systems, heat exchangers and, in particular, cooling systems for internal combustion engines. The cooling liquid is especially designed to cool units, especially internal combustion engines, made of magnesium and/or magnesium alloys.
Cooling systems in general and, in particular, cooling systems for internal combustion engines, such as motor vehicle engines, consist of a variety of different metals, such as copper, brass, steel, cast iron, aluminum, magnesium and alloys thereof.
Furthermore solders, such as soldering tin, are generally present. This material composition brings with it particular problems of corrosion, especially in automobile cooling systems where high temperatures, pressures and flow speeds are present in the cooling system.
Corrosion shortens the service life of the cooling system and leads to a reduction in efficiency through the build-up of undesirable deposits. Cooling liquids which are suitable for automobile cooling systems, for example, have therefore not only to have freezing points which are markedly below 0°C, for example between -20 and -30 °C, but must also be effectively protected against corrosion.
At present, grey cast iron or aluminum engines are the most commonly used in the automobile industry. The prior art, as referred to below, discloses serviceable corrosion-inhibiting cooling liquids for these materials.
A water-soluble liquid alcohol component, in particular ethylene glycol, is conventionally used for the purpose of lowering the freezing point. In addition to these alcohol components, anti-corrosive agents are absolutely essential. Nowadays, these are required to be effective in particularly low concentrations and as far as possible not to contain substances which might be questionable from the point of view of toxicology and/or damaging to the environment.
Antifreeze agents for cooling systems for grey cast iron and aluminum engines are known ' CA 02307621 2000-04-17 from the prior art which contain, in addition to the alcohol components, an anti-corrosive system based on a combination of certain carboxylic acids with triazoles, the efficiency of which may be improved by further anti-corrosive additives, such as borates, phosphates or silicates.
For example, EP-A-251 480 discloses a corrosion-inhibited concentrated antifreeze which contains, in addition to from 90 to 99 wt. % alcohol, 0.1 to 5 wt. %
alkylbenzoic acid or the salts thereof, 0.1 to 5 wt. % of an aliphatic monocarboxylic acid having from 8 to 12 carbon atoms and 0.1 to 0.5 wt. % of a triazole.
EP-B-308 037 discloses an antifreeze composition having corrosion-inhibiting properties, which consists essentially of: 90 to 99 wt. % of a water-soluble liquid alcohol medium for depressing freezing point, 0.1 to 5 wt. % of an aliphatic monobasic acid having from 6 to 12 carbon atoms, 0.1 to 5 wt. % of an alkali metal/borate compound and 0.1 to 0.5 wt. % of a triazole.
An alcohol-based concentrated antifreeze is known from EP-B-229 440 which contains 0.1 to 15 wt. % of an aliphatic monocarboxylic acid having from 5 to 16 carbon atoms, 0.1 to 15 wt. % of a dicarboxylic acid having from 5 to 16 carbon atoms and 0.1 to 0.5 wt. % of a triazole, wherein the weight percentages are based on the amount of liquid alcohol present.
According to the relatively narrow teaching of these three documents, ethylene glycol is preferably used as the alcohol component and benzotriazole or tolyltriazole are preferably used as the triazole. DD-A-218 635 proposes the use of a mixture containing 2-ethylhexanoic acid, mercaptobenzothiazole and carboxymethylcellulose or reaction products of these three components as the anti-corrosive system for cooling or heating media.
DE-A-195 46 472 proposes a concentrated antifreeze in which the anti-corrosive system consists of from 0.005 to 5 wt. % branched aliphatic carboxylic acids having from 6 to 11 carbon atoms and a synergistic combination of from 0.005 to 0.04 wt. % of each of tolyltriazole and benzotriazole.
When used to cool engines of grey cast iron or of aluminum alloys, these antifreeze agents -' CA 02307621 2000-04-17 adequately fulfil the technical requirements. However, attempts are currently being made in the automobile construction industry to reduce the weight of internal combustion engines by making them partially or completely of magnesium and/or magnesium alloys.
Tests have shown that, owing to the increased chemical reactivity of these materials, the conventional antifreeze agents do not fulfil the anti-corrosive requirements when diluted with considerable amounts of water, as is conventional. An object of the present invention is therefore to provide a cooling liquid with which units, such as internal combustion engines of magnesium and/or magnesium alloys in particular, may be cooled without unacceptable corrosion damage.
This object is achieved by using a cooling liquid which, based on the total composition, comprises:
(a) 0.005 to 0.5 wt. % tolyltriazole (b) 0.005 to 0.5 wt. % benzotriazole (c) 0.005 to 10 wt. % of one or more corrosion inhibitors selected from branched aliphatic carboxylic acids having 6 to 11 carbon atoms and alkanolamine phosphates (d) 70 to 99.985 wt. % of a water-soluble liquid alcohol having a boiling point at normal pressure of over 100°C
this being made up to 100 wt. % with water, alkalis and/or other active substances, for cooling units made of magnesium and/or magnesium alloys.
Pure magnesium is not generally used for the construction of internal combustion engines, but rather magnesium alloys. Examples of such alloys are: AS 21 and AZ 91.
The use according to the present invention differs from the use of similar cooling liquids known in the prior art for materials other than magnesium and magnesium alloys in that the cooling liquid having the above-mentioned composition is used as it is. Thus, it is not further diluted with water. The water content of the cooling liquid used according to the present invention consequently amounts to a maximum of 30 wt. % and is preferably less. The cooling liquid preferably contains no more than approximately 15 wt. % water.
By way of example, cooling liquids of this type may be used in accordance with the present invention having a water content of less than 5 wt. % .
_v "Cooling liquid for use in units made of magnesium"
This invention relates to an alcohol-based cooling or heating medium. It may be used in cooling or heating systems, such as air-conditioning systems, heat exchangers and, in particular, cooling systems for internal combustion engines. The cooling liquid is especially designed to cool units, especially internal combustion engines, made of magnesium and/or magnesium alloys.
Cooling systems in general and, in particular, cooling systems for internal combustion engines, such as motor vehicle engines, consist of a variety of different metals, such as copper, brass, steel, cast iron, aluminum, magnesium and alloys thereof.
Furthermore solders, such as soldering tin, are generally present. This material composition brings with it particular problems of corrosion, especially in automobile cooling systems where high temperatures, pressures and flow speeds are present in the cooling system.
Corrosion shortens the service life of the cooling system and leads to a reduction in efficiency through the build-up of undesirable deposits. Cooling liquids which are suitable for automobile cooling systems, for example, have therefore not only to have freezing points which are markedly below 0°C, for example between -20 and -30 °C, but must also be effectively protected against corrosion.
At present, grey cast iron or aluminum engines are the most commonly used in the automobile industry. The prior art, as referred to below, discloses serviceable corrosion-inhibiting cooling liquids for these materials.
A water-soluble liquid alcohol component, in particular ethylene glycol, is conventionally used for the purpose of lowering the freezing point. In addition to these alcohol components, anti-corrosive agents are absolutely essential. Nowadays, these are required to be effective in particularly low concentrations and as far as possible not to contain substances which might be questionable from the point of view of toxicology and/or damaging to the environment.
Antifreeze agents for cooling systems for grey cast iron and aluminum engines are known ' CA 02307621 2000-04-17 from the prior art which contain, in addition to the alcohol components, an anti-corrosive system based on a combination of certain carboxylic acids with triazoles, the efficiency of which may be improved by further anti-corrosive additives, such as borates, phosphates or silicates.
For example, EP-A-251 480 discloses a corrosion-inhibited concentrated antifreeze which contains, in addition to from 90 to 99 wt. % alcohol, 0.1 to 5 wt. %
alkylbenzoic acid or the salts thereof, 0.1 to 5 wt. % of an aliphatic monocarboxylic acid having from 8 to 12 carbon atoms and 0.1 to 0.5 wt. % of a triazole.
EP-B-308 037 discloses an antifreeze composition having corrosion-inhibiting properties, which consists essentially of: 90 to 99 wt. % of a water-soluble liquid alcohol medium for depressing freezing point, 0.1 to 5 wt. % of an aliphatic monobasic acid having from 6 to 12 carbon atoms, 0.1 to 5 wt. % of an alkali metal/borate compound and 0.1 to 0.5 wt. % of a triazole.
An alcohol-based concentrated antifreeze is known from EP-B-229 440 which contains 0.1 to 15 wt. % of an aliphatic monocarboxylic acid having from 5 to 16 carbon atoms, 0.1 to 15 wt. % of a dicarboxylic acid having from 5 to 16 carbon atoms and 0.1 to 0.5 wt. % of a triazole, wherein the weight percentages are based on the amount of liquid alcohol present.
According to the relatively narrow teaching of these three documents, ethylene glycol is preferably used as the alcohol component and benzotriazole or tolyltriazole are preferably used as the triazole. DD-A-218 635 proposes the use of a mixture containing 2-ethylhexanoic acid, mercaptobenzothiazole and carboxymethylcellulose or reaction products of these three components as the anti-corrosive system for cooling or heating media.
DE-A-195 46 472 proposes a concentrated antifreeze in which the anti-corrosive system consists of from 0.005 to 5 wt. % branched aliphatic carboxylic acids having from 6 to 11 carbon atoms and a synergistic combination of from 0.005 to 0.04 wt. % of each of tolyltriazole and benzotriazole.
When used to cool engines of grey cast iron or of aluminum alloys, these antifreeze agents -' CA 02307621 2000-04-17 adequately fulfil the technical requirements. However, attempts are currently being made in the automobile construction industry to reduce the weight of internal combustion engines by making them partially or completely of magnesium and/or magnesium alloys.
Tests have shown that, owing to the increased chemical reactivity of these materials, the conventional antifreeze agents do not fulfil the anti-corrosive requirements when diluted with considerable amounts of water, as is conventional. An object of the present invention is therefore to provide a cooling liquid with which units, such as internal combustion engines of magnesium and/or magnesium alloys in particular, may be cooled without unacceptable corrosion damage.
This object is achieved by using a cooling liquid which, based on the total composition, comprises:
(a) 0.005 to 0.5 wt. % tolyltriazole (b) 0.005 to 0.5 wt. % benzotriazole (c) 0.005 to 10 wt. % of one or more corrosion inhibitors selected from branched aliphatic carboxylic acids having 6 to 11 carbon atoms and alkanolamine phosphates (d) 70 to 99.985 wt. % of a water-soluble liquid alcohol having a boiling point at normal pressure of over 100°C
this being made up to 100 wt. % with water, alkalis and/or other active substances, for cooling units made of magnesium and/or magnesium alloys.
Pure magnesium is not generally used for the construction of internal combustion engines, but rather magnesium alloys. Examples of such alloys are: AS 21 and AZ 91.
The use according to the present invention differs from the use of similar cooling liquids known in the prior art for materials other than magnesium and magnesium alloys in that the cooling liquid having the above-mentioned composition is used as it is. Thus, it is not further diluted with water. The water content of the cooling liquid used according to the present invention consequently amounts to a maximum of 30 wt. % and is preferably less. The cooling liquid preferably contains no more than approximately 15 wt. % water.
By way of example, cooling liquids of this type may be used in accordance with the present invention having a water content of less than 5 wt. % .
When carboxylic acids are mentioned in the present context, what is generally meant is the acids in protolysed or non-protolysed form, i.e. the acids may be present as such or as anions. The protolysis equilibrium of the acids is adjusted according to the acidity constants depending on the pH of the cooling liquid.
The branched aliphatic carboxylic acids (c) are present in the cooling liquid within the preferred concentration range of from 0.5 to 4 wt. % and the tolyltriazole and benzotriazole are each present within the preferred concentration range of from 0.005 to 0.05 wt. % . If an alkanolamine phosphate is selected as the corrosion inhibitor (c), its concentration is preferably set at from about 0.1 to about 10 wt. %. In this case, trialkanolamine phosphate, and especially triethanolamine phosphate is selected as the alkanolamine phosphate.
The water-soluble liquid alcohol should have a boiling point at normal pressure of over 100°C and especially over 120°C. The "liquid" criterion is to be understood to mean that the selected alcohol is liquid at the temperatures which may occur when the unit to be cooled is either at a standstill or in operation. The temperature range which is in practice relevant extends from about -35 to about 110°C. The cooling liquid may be used in a closed cooling system, in which an operating pressure markedly above normal pressure may build up during operation of the unit to be cooled. The decisive factor is whether the alcohol used remains liquid under the prevailing pressure and temperature conditions.
The water-soluble liquid alcohol is preferably selected from alkene glycols, especially from monoethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol and/or from water-miscible monoethers thereof, for example monomethyl, monoethyl, monopropyl and monobutyl ethers of the above-mentioned glycols. Monoethylene glycol and/or propylene glycol are particularly preferable.
If branched aliphatic carboxylic acids are selected as the anti-corrosive component (c), the latter are preferably selected from 2-ethylhexanoic acid, 2,2-dimethyloctanoic acid and 3,5,5-trimethylhexanoic acid or mixtures thereof. Owing to its easy availability and good anti-corrosive action, 2-ethylhexanoic acid is particularly preferable.
' CA 02307621 2000-04-17 -$-It is also preferable for the cooling liquid additionally to contain as a further active substance from 0.5 to 1$ wt. % of one or more linear saturated or unsaturated aliphatic, araliphatic or aromatic mono- or poly-basic carboxylic acids having from 4 to 20 carbon atoms. The anti-corrosive effect is markedly improved thereby. The lower limit for the carbon number, i.e.
4 carbon atoms, relates to aliphatic carboxylic acids. Aromatic carboxylic acids must contain at least 7 carbon atoms. The carboxylic acids which may be optionally introduced are preferably selected from sebacic acid, caprylic acid, nonanoic acid, decanoic acid, undecanoic acid, benzoic acid, cinnamic acid, gluconic acid or mixtures thereof. Acids which are particularly preferred are sebacic acid, caprylic acid and cinnamic acid.
In addition to these acids, the cooling liquids may contain polybasic carboxylic acids having a particularly marked complexing action, for example tartaric acid and especially citric acid.
Another active substance which reinforces the anti-corrosive action, especially in the case of non-ferrous heavy metal components, is mercaptobenzothiazole, which is introduced into the cooling liquid in amounts of between 0.0001 and 0.$ wt. %, preferably between 0.002 and 0.0$ wt. % . The action of the mercaptobenzothiazole is further increased by the additional use of carboxymethyl-cellulose. It is therefore preferable for the cooling liquid additionally to contain, as a further active substance, from 0.0001 to 0.$ wt. %, especially 0.002 to 0.0$
wt. %, of carboxymethylcellulose. Mercaptobenzo-thiazole and carboxymethylcellulose may be added to the cooling liquid independently of each other. However, according to the teaching of DD 218 635 it is preferable to prepare at an elevated temperature ($0 to 6$°C) a preliminary mixture of branched aliphatic carboxylic acid (c), mercaptobenzothiazole and carboxymethyl-cellulose, in which preliminary mixture partial reactions of these reactants may occur. This preliminary product is preferably produced by starting with a concentrated aqueous-alkaline carboxymethylcellulose solution, to which the mercaptobenzothiazole is added with stirring in the temperature range of from $0 to 6$°C, the branched carboxylic acid being slowly added to this mixture after many hours of reaction time. The weight ratio of the three active substances carboxymethylcellulose, mercaptobenzo-thiazole and branched aliphatic carboxylic acid preferably ranges from 1 : 1 : 1 to 1 : $ : $0. If it is desired to increase the amount of branched aliphatic carboxylic acid in the cooling liquid to above the upper limit given in this quantitative ratio, the desired amount of acid is additionally added.
The cooling liquid may contain additional inhibiting components known from the prior art.
For example, zinc salts and alkali metal or ammonium molybdates may be introduced in amounts of from 0.01 to 2 wt. %. A prerequisite of this, however, is that sufficient water must be present in the cooling liquid for these components to dissolve.
Furthermore, a cooling liquid is preferably used which is free from nitrite, borate and silicate.
_7_ Examples Table 1 contains Examples of anhydrous cooling liquids for use according to the present invention. The composition is given in wt. %. "Anhydrous" in this context should be understood to mean that no water has been added to the cooling liquid.
However, it is not impossible that the cooling liquid may contain small amounts of water owing to the hygroscopic properties of monoethylene glycol.
Table 1: Anhydrous cooling liquids Example (in wt. %) (made up to 100 wt. % with monoethylene glycol) Ex. 1 Ex.2 Ex.3 Benzotriazole 0.02 0.01 0.015 Tolyltriazole 0.02 0.01 0.01 2-ethylhexanoic acid2.5 3.8 -Sebacic acid 1 - -Caprylic acid - 1 -Mercaptobenzo-thiazole- - 0.03 Carboxymethyl- 0.0001 0.0002 -cellulose Triethanolamine - - 2 phosphate The anti-corrosive effect was tested in accordance with ASTM testing specification D 1384-70. Samples of metals typically present in motor vehicle cooling systems were immersed completely in the antifreeze solution for 336 hours with simultaneous aeration. The _g_ temperature was 88°C. The corrosion-inhibiting properties of the test solutions were evaluated on the basis of the changes in weight of the samples. Each test was carried out 3 times and the average weight change was determined for each metal. Before the test started, the samples were bright-polished with a moist scrubbing brush and ground pounce, washed with water and then acetone, dried and weighed. When the test was complete, the corrosion products on the samples were removed by brushing and by immersion in acid solutions. The samples were then washed, dried and weighed again. Table 2 contains the weight losses (in g/mz) for various metals using the exemplary or comparative solutions.
The test solutions were the solutions according to Examples 1 to 3 having different amounts of added water. The percentages in Table 2 are wt. % based on the resultant total mixture.
The following Examples were examined: the anhydrous cooling liquids according to Example 1 additionally had 10 wt. %, 20 wt. % and 30 wt. % water added, the cooling liquid according to Example 2 had 10 wt. % water added and the cooling liquid according to Example 3 had S wt. % water added. As a Comparative Example, the cooling liquid according to Example 1 had 50 wt. % water added.
The corrosion inspections carried out on the tested metals show that all the test liquids including the comparative solution provided acceptable corrosion results apart from in the case of magnesium. In the case of magnesium, however, acceptable corrosion behavior was noted only when the test liquid contained up to 30 wt. % water. As the Comparative Example shows, when the water content is 50 wt. % , severe corrosion with pitting occurs.
O
+
c ~ an O c .
ctt ~ 3 ~n Q.
E
U ~ 0 0 0 0 0 0 i M
ed 3 -. 0 0 0 0 0 0 N
ar C~
M O~ ~ 0 ~ --m p 0 0 0 0 .~ o i M
+
i 4.
cC
~O ~ N O O wt Ov O ~ O O N
O
N
+
LL~
N
a O 3 . M ~O O O 00 M
a0 00 b~ ~~ N O ~~ N
C
=p O
O +
c~
y yr ~ ~ _~
a. CC N ..~ M N
~ f.Ll O ~ O --~
C~ ~
O
U
i ....
O
y N .
a O
N ~ _N ~.., U
. cp c~ ~. ,~ ~ ~ ~, U N
a. ~ ;? ~n an v~
3 ~ v ~ m ~ c~ a ~ Q
The branched aliphatic carboxylic acids (c) are present in the cooling liquid within the preferred concentration range of from 0.5 to 4 wt. % and the tolyltriazole and benzotriazole are each present within the preferred concentration range of from 0.005 to 0.05 wt. % . If an alkanolamine phosphate is selected as the corrosion inhibitor (c), its concentration is preferably set at from about 0.1 to about 10 wt. %. In this case, trialkanolamine phosphate, and especially triethanolamine phosphate is selected as the alkanolamine phosphate.
The water-soluble liquid alcohol should have a boiling point at normal pressure of over 100°C and especially over 120°C. The "liquid" criterion is to be understood to mean that the selected alcohol is liquid at the temperatures which may occur when the unit to be cooled is either at a standstill or in operation. The temperature range which is in practice relevant extends from about -35 to about 110°C. The cooling liquid may be used in a closed cooling system, in which an operating pressure markedly above normal pressure may build up during operation of the unit to be cooled. The decisive factor is whether the alcohol used remains liquid under the prevailing pressure and temperature conditions.
The water-soluble liquid alcohol is preferably selected from alkene glycols, especially from monoethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol and/or from water-miscible monoethers thereof, for example monomethyl, monoethyl, monopropyl and monobutyl ethers of the above-mentioned glycols. Monoethylene glycol and/or propylene glycol are particularly preferable.
If branched aliphatic carboxylic acids are selected as the anti-corrosive component (c), the latter are preferably selected from 2-ethylhexanoic acid, 2,2-dimethyloctanoic acid and 3,5,5-trimethylhexanoic acid or mixtures thereof. Owing to its easy availability and good anti-corrosive action, 2-ethylhexanoic acid is particularly preferable.
' CA 02307621 2000-04-17 -$-It is also preferable for the cooling liquid additionally to contain as a further active substance from 0.5 to 1$ wt. % of one or more linear saturated or unsaturated aliphatic, araliphatic or aromatic mono- or poly-basic carboxylic acids having from 4 to 20 carbon atoms. The anti-corrosive effect is markedly improved thereby. The lower limit for the carbon number, i.e.
4 carbon atoms, relates to aliphatic carboxylic acids. Aromatic carboxylic acids must contain at least 7 carbon atoms. The carboxylic acids which may be optionally introduced are preferably selected from sebacic acid, caprylic acid, nonanoic acid, decanoic acid, undecanoic acid, benzoic acid, cinnamic acid, gluconic acid or mixtures thereof. Acids which are particularly preferred are sebacic acid, caprylic acid and cinnamic acid.
In addition to these acids, the cooling liquids may contain polybasic carboxylic acids having a particularly marked complexing action, for example tartaric acid and especially citric acid.
Another active substance which reinforces the anti-corrosive action, especially in the case of non-ferrous heavy metal components, is mercaptobenzothiazole, which is introduced into the cooling liquid in amounts of between 0.0001 and 0.$ wt. %, preferably between 0.002 and 0.0$ wt. % . The action of the mercaptobenzothiazole is further increased by the additional use of carboxymethyl-cellulose. It is therefore preferable for the cooling liquid additionally to contain, as a further active substance, from 0.0001 to 0.$ wt. %, especially 0.002 to 0.0$
wt. %, of carboxymethylcellulose. Mercaptobenzo-thiazole and carboxymethylcellulose may be added to the cooling liquid independently of each other. However, according to the teaching of DD 218 635 it is preferable to prepare at an elevated temperature ($0 to 6$°C) a preliminary mixture of branched aliphatic carboxylic acid (c), mercaptobenzothiazole and carboxymethyl-cellulose, in which preliminary mixture partial reactions of these reactants may occur. This preliminary product is preferably produced by starting with a concentrated aqueous-alkaline carboxymethylcellulose solution, to which the mercaptobenzothiazole is added with stirring in the temperature range of from $0 to 6$°C, the branched carboxylic acid being slowly added to this mixture after many hours of reaction time. The weight ratio of the three active substances carboxymethylcellulose, mercaptobenzo-thiazole and branched aliphatic carboxylic acid preferably ranges from 1 : 1 : 1 to 1 : $ : $0. If it is desired to increase the amount of branched aliphatic carboxylic acid in the cooling liquid to above the upper limit given in this quantitative ratio, the desired amount of acid is additionally added.
The cooling liquid may contain additional inhibiting components known from the prior art.
For example, zinc salts and alkali metal or ammonium molybdates may be introduced in amounts of from 0.01 to 2 wt. %. A prerequisite of this, however, is that sufficient water must be present in the cooling liquid for these components to dissolve.
Furthermore, a cooling liquid is preferably used which is free from nitrite, borate and silicate.
_7_ Examples Table 1 contains Examples of anhydrous cooling liquids for use according to the present invention. The composition is given in wt. %. "Anhydrous" in this context should be understood to mean that no water has been added to the cooling liquid.
However, it is not impossible that the cooling liquid may contain small amounts of water owing to the hygroscopic properties of monoethylene glycol.
Table 1: Anhydrous cooling liquids Example (in wt. %) (made up to 100 wt. % with monoethylene glycol) Ex. 1 Ex.2 Ex.3 Benzotriazole 0.02 0.01 0.015 Tolyltriazole 0.02 0.01 0.01 2-ethylhexanoic acid2.5 3.8 -Sebacic acid 1 - -Caprylic acid - 1 -Mercaptobenzo-thiazole- - 0.03 Carboxymethyl- 0.0001 0.0002 -cellulose Triethanolamine - - 2 phosphate The anti-corrosive effect was tested in accordance with ASTM testing specification D 1384-70. Samples of metals typically present in motor vehicle cooling systems were immersed completely in the antifreeze solution for 336 hours with simultaneous aeration. The _g_ temperature was 88°C. The corrosion-inhibiting properties of the test solutions were evaluated on the basis of the changes in weight of the samples. Each test was carried out 3 times and the average weight change was determined for each metal. Before the test started, the samples were bright-polished with a moist scrubbing brush and ground pounce, washed with water and then acetone, dried and weighed. When the test was complete, the corrosion products on the samples were removed by brushing and by immersion in acid solutions. The samples were then washed, dried and weighed again. Table 2 contains the weight losses (in g/mz) for various metals using the exemplary or comparative solutions.
The test solutions were the solutions according to Examples 1 to 3 having different amounts of added water. The percentages in Table 2 are wt. % based on the resultant total mixture.
The following Examples were examined: the anhydrous cooling liquids according to Example 1 additionally had 10 wt. %, 20 wt. % and 30 wt. % water added, the cooling liquid according to Example 2 had 10 wt. % water added and the cooling liquid according to Example 3 had S wt. % water added. As a Comparative Example, the cooling liquid according to Example 1 had 50 wt. % water added.
The corrosion inspections carried out on the tested metals show that all the test liquids including the comparative solution provided acceptable corrosion results apart from in the case of magnesium. In the case of magnesium, however, acceptable corrosion behavior was noted only when the test liquid contained up to 30 wt. % water. As the Comparative Example shows, when the water content is 50 wt. % , severe corrosion with pitting occurs.
O
+
c ~ an O c .
ctt ~ 3 ~n Q.
E
U ~ 0 0 0 0 0 0 i M
ed 3 -. 0 0 0 0 0 0 N
ar C~
M O~ ~ 0 ~ --m p 0 0 0 0 .~ o i M
+
i 4.
cC
~O ~ N O O wt Ov O ~ O O N
O
N
+
LL~
N
a O 3 . M ~O O O 00 M
a0 00 b~ ~~ N O ~~ N
C
=p O
O +
c~
y yr ~ ~ _~
a. CC N ..~ M N
~ f.Ll O ~ O --~
C~ ~
O
U
i ....
O
y N .
a O
N ~ _N ~.., U
. cp c~ ~. ,~ ~ ~ ~, U N
a. ~ ;? ~n an v~
3 ~ v ~ m ~ c~ a ~ Q
Claims (9)
1. Use of a cooling liquid which, based on the total composition, comprises:
(a) 0.005 to 0.5 wt. % tolyltriazole (b) 0.005 to 0.5 wt. % benzotriazole (c) 0.005 to 10 wt. % of one or more corrosion inhibitors selected from branched aliphatic carboxylic acids having 6 to 11 carbon atoms and alkanolamine phosphates (d) 70 to 99.985 wt. % of a water-soluble liquid alcohol having a boiling point at normal pressure of over 100°C
this being made up to 100 wt. % with water, alkalis and/or other active substances, for cooling units made of magnesium and/or magnesium alloys.
(a) 0.005 to 0.5 wt. % tolyltriazole (b) 0.005 to 0.5 wt. % benzotriazole (c) 0.005 to 10 wt. % of one or more corrosion inhibitors selected from branched aliphatic carboxylic acids having 6 to 11 carbon atoms and alkanolamine phosphates (d) 70 to 99.985 wt. % of a water-soluble liquid alcohol having a boiling point at normal pressure of over 100°C
this being made up to 100 wt. % with water, alkalis and/or other active substances, for cooling units made of magnesium and/or magnesium alloys.
2. Use according to claim 1 wherein the water-soluble liquid alcohol is selected from alkylene glycols.
3. Use according to claim 2 wherein the water-soluble liquid alcohol is selected from monoethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol and/or from the monomethyl, monoethyl, monopropyl and monobutyl ethers of the above-mentioned glycols.
4. Use according to one or more of claims 1 to 3 wherein the corrosion inhibitor is selected from 2-ethyl hexanoic acid, 2,2-dimethyloctanoic acid and 3,5,5-trimethylhexanoic acid or mixtures thereof.
5. Use according to one or more of claims 1 to 3 wherein the corrosion inhibitor is triethanolamine phosphate.
6. Use according to one or more of claims 1 to 5 wherein the cooling liquid additionally contains, as a further active substance, from 0.5 to 15 wt. % of one or more linear saturated or unsaturated aliphatic, araliphatic or aromatic mono- or poly-basic carboxylic acids having from 4 to 20 carbon atoms.
7. Use according to one or more of claims 1 to 6 wherein the cooling liquid additionally contains, as a further active substance, from 0.0001 to 0.5 wt.
mercaptobenzothiazole.
mercaptobenzothiazole.
8. Use according to one or more of claims 1 to 7 wherein the cooling liquid additionally contains, as a further active substance, from 0.0001 to 0.5 wt.
carboxymethylcellulose.
carboxymethylcellulose.
9. Use according to one or more of claims 1 to 8 wherein the cooling liquid is free from nitrite, borate and silicate.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19745461.5 | 1997-10-15 | ||
| DE19745461A DE19745461A1 (en) | 1997-10-15 | 1997-10-15 | Liquid coolant for magnesium-based engine components |
| PCT/EP1998/006367 WO1999019418A1 (en) | 1997-10-15 | 1998-10-07 | Cooling liquid for utilizing in components made of magnesium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2307621A1 true CA2307621A1 (en) | 1999-04-22 |
Family
ID=7845564
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002307621A Abandoned CA2307621A1 (en) | 1997-10-15 | 1998-10-07 | Cooling composition for use with magnesium materials |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP1025181B1 (en) |
| AT (1) | ATE211500T1 (en) |
| CA (1) | CA2307621A1 (en) |
| CZ (1) | CZ294135B6 (en) |
| DE (2) | DE19745461A1 (en) |
| ES (1) | ES2170534T3 (en) |
| WO (1) | WO1999019418A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009035741A1 (en) * | 2007-06-28 | 2009-03-19 | Chevron U.S.A Inc. | Antifreeze concentrate and coolant compositions and preparation thereof |
| US8333904B2 (en) | 2000-07-24 | 2012-12-18 | Basf Aktiengesellschaft | Antifreeze concentrates based on amides, and coolant compositions comprising them and intended for protecting magnesium and magnesium alloys |
| WO2014200913A1 (en) * | 2013-06-12 | 2014-12-18 | Ashland Licensing And Intellectual Property Llc | Extended operation engine coolant composition |
| US9540558B2 (en) | 2013-06-12 | 2017-01-10 | Ashland Licensing And Intellectual Property, Llc | Extended operation engine coolant composition |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10313280A1 (en) | 2003-03-25 | 2004-10-07 | Basf Ag | Antifreeze concentrates and coolant compositions based on polyglycols and amides for the protection of magnesium and its alloys |
| JP4796507B2 (en) | 2004-11-26 | 2011-10-19 | シーシーアイ株式会社 | Heat medium composition |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4389371A (en) * | 1979-09-14 | 1983-06-21 | Basf Wyandotte Corporation | Process for inhibiting the corrosion of aluminum |
| US4647392A (en) * | 1985-12-27 | 1987-03-03 | Texaco Inc. | Monobasic-dibasic acid/salt antifreeze corrosion inhibitor |
| US4851145A (en) * | 1986-06-30 | 1989-07-25 | S.A. Texaco Petroleum Nv | Corrosion-inhibited antifreeze/coolant composition |
| DE3708298A1 (en) * | 1987-03-14 | 1988-09-22 | Basf Ag | NITRITE AND PHOSPHATE-FREE GLYCOL-BASED REFRIGERANT BLENDS |
| US4759864A (en) * | 1987-09-04 | 1988-07-26 | Texaco Inc. & S.A. Texaco Petro, N.V. | Corrosion-inhibited antifreeze formulation |
| BR8907364A (en) * | 1988-04-15 | 1991-04-23 | Dow Chemical Co | GLYCOL INHIBITED ALKYLENE REFRIGERANT AND REFRIGERATION PROCESS |
| ES2103888T3 (en) * | 1992-04-06 | 1997-10-01 | Texaco Services Europ Ltd | CORROSION INHIBITING ANTIFREEZE FORMULATIONS. |
| DE19546472A1 (en) * | 1995-12-13 | 1997-06-19 | Henkel Kgaa | Antifreeze |
-
1997
- 1997-10-15 DE DE19745461A patent/DE19745461A1/en not_active Withdrawn
-
1998
- 1998-10-07 AT AT98954365T patent/ATE211500T1/en not_active IP Right Cessation
- 1998-10-07 WO PCT/EP1998/006367 patent/WO1999019418A1/en active IP Right Grant
- 1998-10-07 CZ CZ20001366A patent/CZ294135B6/en not_active IP Right Cessation
- 1998-10-07 ES ES98954365T patent/ES2170534T3/en not_active Expired - Lifetime
- 1998-10-07 EP EP98954365A patent/EP1025181B1/en not_active Expired - Lifetime
- 1998-10-07 CA CA002307621A patent/CA2307621A1/en not_active Abandoned
- 1998-10-07 DE DE59802813T patent/DE59802813D1/en not_active Expired - Lifetime
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8333904B2 (en) | 2000-07-24 | 2012-12-18 | Basf Aktiengesellschaft | Antifreeze concentrates based on amides, and coolant compositions comprising them and intended for protecting magnesium and magnesium alloys |
| WO2009035741A1 (en) * | 2007-06-28 | 2009-03-19 | Chevron U.S.A Inc. | Antifreeze concentrate and coolant compositions and preparation thereof |
| US7790054B2 (en) | 2007-06-28 | 2010-09-07 | Chevron U.S.A. Inc. | Antifreeze concentrate and coolant compositions and preparation thereof |
| WO2014200913A1 (en) * | 2013-06-12 | 2014-12-18 | Ashland Licensing And Intellectual Property Llc | Extended operation engine coolant composition |
| CN105339459A (en) * | 2013-06-12 | 2016-02-17 | 亚什兰许可和知识产权有限公司 | Extended operation engine coolant composition |
| US9328278B2 (en) | 2013-06-12 | 2016-05-03 | Ashland Licensing And Intellectual Property Llc | Extended operation engine coolant composition |
| US9540558B2 (en) | 2013-06-12 | 2017-01-10 | Ashland Licensing And Intellectual Property, Llc | Extended operation engine coolant composition |
| AU2019204001B2 (en) * | 2013-06-12 | 2020-11-05 | Vgp Ipco Llc | Extended operation engine coolant composition |
Also Published As
| Publication number | Publication date |
|---|---|
| EP1025181B1 (en) | 2002-01-02 |
| ES2170534T3 (en) | 2002-08-01 |
| WO1999019418A1 (en) | 1999-04-22 |
| ATE211500T1 (en) | 2002-01-15 |
| DE59802813D1 (en) | 2002-02-28 |
| EP1025181A1 (en) | 2000-08-09 |
| DE19745461A1 (en) | 1999-04-22 |
| CZ20001366A3 (en) | 2001-02-14 |
| CZ294135B6 (en) | 2004-10-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2093411C (en) | Corrosion-inhibited antifreeze formulations | |
| CA1258162A (en) | Monobasic-dibasic acid/salt antifreeze corrosion inhibitor | |
| US4759864A (en) | Corrosion-inhibited antifreeze formulation | |
| EP0251480B1 (en) | Corrosion-inhibited antifreeze/coolant composition | |
| CN1072252C (en) | Silicate-, borate- and nitrate-free antifreeze concentrates and coolant compositions comprising them | |
| JP3113021B2 (en) | Antifreeze / coolant compositions containing aromatic carboxylic acids and having corrosion inhibiting properties | |
| EP0995785A1 (en) | Corrosion inhibitors and synergistic inhibitor combinations for the protection of light metals in heat-transfer fluids and engine coolants | |
| US6045719A (en) | Use of quaternized imidazoles as corrosion inhibitors for non-ferrous metals, and coolant compositions and antifreeze concentrates comprising them | |
| JPH06116764A (en) | Antifreeze composition | |
| CA2051278C (en) | Corrosion-inhibited antifreeze/coolant composition containing cyclohexane acid(s) | |
| JP3028182B2 (en) | Coolant composition | |
| CA2308195C (en) | Silicate free antifreeze composition | |
| CA2051609A1 (en) | Corrosion-inhibited antifreeze/coolant composition | |
| CA2307621A1 (en) | Cooling composition for use with magnesium materials | |
| CZ183598A3 (en) | Antifreezer agent | |
| JP2004068155A (en) | Antifreeze | |
| KR100473217B1 (en) | Antifreeze concentrates containing silicates, borates and nitrates, and cooling formulations containing them | |
| JPH1046134A (en) | Antifreeze composition | |
| EP1829949B1 (en) | Heat carrier composition | |
| IL123458A (en) | Corrosion inhibitory composition for use with metal based cooling systems | |
| MXPA00004372A (en) | Silicate free antifreeze composition |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |