JP2014101411A - Coolant composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coolant composition capable of improving the fuel efficiency of an internal combustion engine and a method for cooling an internal combustion engine by using the same.SOLUTION: The provided coolant composition not only comprises: a lipid peptide or salt thereof as a viscosity characteristic enhancer; and a base in a state where the lipid peptide comprises a lipid monopeptide constituted by a fatty acid and a monopeptide and/or a lipid dipeptide constituted by a fatty acid and a dipeptide. The base includes: at least one type of alcohol selected from the group consisting of monovalent alcohols, divalent alcohols, trivalent alcohols, and glycol monoalkyl ethers; and/or water but also exhibits kinetic viscosities of 8.5 mm/sec or above at 25°C and 2.0 mm/sec or below at 100°C.

Description

  The present invention relates to a coolant composition capable of improving the fuel efficiency of an internal combustion engine and a cooling method for an internal combustion engine using the same.

  Various coolants for cooling automobile engines and the like are known, and among them, water is preferable because it has the highest cooling performance as an engine coolant. However, fresh water freezes when it falls below 0 ° C. Under these circumstances, for the purpose of antifreezing, it is diluted with water so as to obtain a necessary freezing temperature based on glycols such as ethylene glycol, and if necessary, metals, rubbers, resins, etc. used for engines, radiators, etc. Coolant compositions containing various additives for protecting the deterioration of the liquid have been used.

  However, when glycols such as ethylene glycol are used, there is a problem that the viscosity of the cooling liquid composition is remarkably increased particularly at a low temperature. Therefore, in the conventional technique for improving viscosity characteristics, generally, viscosity reduction has been performed for improving fluidity at low temperatures (Patent Documents 1-3).

  However, when the viscosity is reduced, the boundary layer between the coolant and the bore wall becomes thinner and convection is likely to occur, so that the coolant tends to take heat away from the bore wall, resulting in increased cooling loss. However, a new problem has arisen that causes a deterioration in fuel consumption. On the other hand, if the viscosity of the coolant at low temperatures is increased by increasing the concentration of glycols such as ethylene glycol in order to reduce the heat dissipation and reduce the cooling loss, the cooling capacity becomes insufficient at high temperatures, leading to overheating. The problem that occurred.

  For example, Patent Documents 4-6 describe a technique for improving the viscosity characteristics of a lubricating oil by blending a viscosity index improver. However, the viscosity index improver described therein exhibits fluidity at low temperatures. It is formulated for the purpose of reducing the decrease in viscosity at high temperatures while maintaining it.Therefore, even when a liquid agent containing such a viscosity index improver is used as a cooling liquid, the cooling loss at low temperature is reduced, In addition, the cooling capacity at high temperatures cannot be maintained.

JP-A-8-183950 JP 2010-236064 A Japanese Patent Laid-Open No. 9-227859 JP 2011-137089 A JP 2011-132285 A JP 2011-121991 A

  An object of the present invention is to provide a coolant composition that can improve the fuel efficiency of an internal combustion engine and a cooling method for an internal combustion engine using the same. Specifically, an object of the present invention is to provide a cooling liquid composition capable of reducing cooling loss at a low temperature and maintaining a cooling capacity at a high temperature, and a cooling method for an internal combustion engine using the same.

  The present inventors have added a specific lipid peptide or a salt thereof as a viscosity property improver to make the kinematic viscosity of the cooling liquid composition within a specific range, thereby reducing cooling loss at low temperatures and at high temperatures. It has been found that the cooling capacity of the internal combustion engine can be greatly improved.

That is, the present invention includes the following inventions.
(1) containing a lipid peptide or a salt thereof as a viscosity property improving agent, and a base,
The lipid peptide is a lipid monopeptide composed of a fatty acid and a monopeptide and / or a lipid dipeptide composed of a fatty acid and a dipeptide,
The base contains at least one alcohol selected from the group consisting of monohydric alcohols, dihydric alcohols, trihydric alcohols and glycol monoalkyl ethers and / or water;
A coolant composition having a kinematic viscosity of 8.5 mm ² / sec or more at 25 ° C. and 2.0 mm ² / sec or less at 100 ° C.

［式中、
Ｒ¹は、炭素原子数９〜１９の、飽和脂肪族基又は１個の不飽和結合を有する不飽和脂肪族基であり、
Ｒ²は、−（ＣＨ₂）_n−Ｘ基であり、ここで、ｎは１〜４の整数であり、Ｘはアミノ基、グアニジノ基、−ＣＯＮＨ₂基、又は窒素原子を１〜３個有し得る５員環若しくは６員環又は５員環と６員環から構成される縮合複素環であり、
＊が付された炭素は不斉炭素を表し、Ｄ又はＬ配置のいずれかである］
で表される脂質モノペプチドである、上記（１）に記載の冷却液組成物。 (2) The lipid peptide has the formula (1):

[Where:
R ¹ is a saturated aliphatic group having 9 to 19 carbon atoms or an unsaturated aliphatic group having one unsaturated bond;
R ² is a — (CH ₂ ) _n —X group, where n is an integer of 1 to 4, and X is an amino group, a guanidino group, a —CONH ₂ group, or 1 to 3 nitrogen atoms. A 5-membered ring or a 6-membered ring or a condensed heterocyclic ring composed of a 5-membered ring and a 6-membered ring,
Carbon marked with * represents an asymmetric carbon and is either D or L configuration]
The coolant composition according to (1) above, which is a lipid monopeptide represented by the formula:

(3) n is an integer of 1 to 4 and X is an amino group, guanidino group or —CONH ₂ group, or n is 1 and X is a pyrrole group, imidazole group, pyrazole group or indole The coolant composition according to (2), which is a group.
(4) The coolant composition according to the above (2) or (3), wherein the asymmetric carbon marked with * is in L configuration.

［式中、
Ｒ³は、炭素原子数９〜２３の、直鎖状飽和脂肪族基又は１若しくは２個の不飽和結合を有する直鎖状不飽和脂肪族基であり、
Ｒ⁴は、水素原子又は炭素原子数１若しくは２の分枝鎖を有し得る炭素原子数１〜４のアルキル基であり、
Ｒ⁵は、−（ＣＨ₂）_n−Ｘ基を表し、ここで、ｎは１〜４の整数を表し、Ｘはアミノ基、グアニジノ基、−ＣＯＮＨ₂基、又は窒素原子を１〜３個有し得る５員環若しくは６員環又は５員環と６員環から構成される縮合複素環であり、
ａ又はｂが付された炭素は不斉炭素を表し、Ｄ又はＬ配置のいずれかである］
で表される脂質ジペプチドである、上記（１）〜（４）のいずれかに記載の冷却液組成物。 (5) The lipid peptide is represented by formula (2):

[Where:
R ³ is a linear saturated aliphatic group having 9 to 23 carbon atoms or a linear unsaturated aliphatic group having 1 or 2 unsaturated bonds,
R ⁴ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a branched chain having 1 or 2 carbon atoms,
R ⁵ represents a — (CH ₂ ) _n —X group, where n represents an integer of 1 to 4, and X represents an amino group, a guanidino group, a —CONH ₂ group, or 1 to 3 nitrogen atoms. A 5-membered ring or a 6-membered ring or a condensed heterocyclic ring composed of a 5-membered ring and a 6-membered ring,
Carbon to which a or b is attached represents an asymmetric carbon and is in either the D or L configuration]
The cooling fluid composition according to any one of the above (1) to (4), which is a lipid dipeptide represented by the formula:

(6) n is an integer of 1 to 4 and X is an amino group, guanidino group or —CONH ₂ group, or n is 1 and X is a pyrrole group, imidazole group, pyrazole group or indole The coolant composition according to (5), which is a group.
(7) R ⁴ is a hydrogen atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group or tert-butyl group, and R ⁵ is amino Methyl group, aminoethyl group, 3-aminopropyl group, 4-aminobutyl group, carbamoylmethyl group, 2-carbamoylethyl group, 3-carbamoylbutyl group, 2-guanidinoethyl group, 3-guanidinobutyl group, pyrrolemethyl group The cooling liquid composition according to (5) or (6) above, which is an imidazole methyl group, a pyrazole methyl group or a 3-indolemethyl group.
(8) The coolant composition according to any one of the above (5) to (7), wherein the asymmetric carbon to which a is attached has an L configuration.
(9) The coolant composition according to any one of (1) to (8), wherein the viscosity characteristic improver is contained in an amount of 0.05 to 4.5 parts by mass with respect to 100 parts by mass of the composition.

FIG. 1 is a diagram showing a conceptual diagram of lipid peptide self-assembly and subsequent gelation. FIG. 2 is a schematic diagram of the warm-up performance and cooling performance evaluation apparatus used in the examples.

  Hereinafter, the present invention will be described in more detail. In the present invention, “n” is normal, “i” is iso, “s” or “sec” is secondary, “t” or “tert” is tertiary, “c” is cyclo, “ “o” means ortho, “m” means meta, “p” means para, “Me” means methyl group, “Bu” means butyl group, and “tBu” means tertiary butyl group. As abbreviations for amino acids, histidine (His), glycine (Gly), valine (Val), isoleucine (Ile), alanine (Ala), arginine (Arg), asparagine (Asn), glutamine (Gln), lysine (Lys) ), Tryptophan (Trp) is used.

  The cooling fluid composition of the present invention contains a specific lipid peptide or a salt thereof as a viscosity property improving agent, and thereby has a specific kinematic viscosity at low and high temperatures. In the present invention, low temperature means 25 ° C., and high temperature means 100 ° C.

  The lipid peptide used in the present invention is not particularly limited as long as it has the property of self-assembling at a low temperature and subsequently gelling (see FIG. 1). Preferably, fatty acid and monopeptide (one amino acid) A lipid monopeptide composed of a fatty acid and a dipeptide (two amino acids). One lipid peptide may be used, or two or more lipid peptides may be used in combination. Preferably 1 type or 2 types are used, More preferably, 1 type is used. However, when two types are used, it can be expected to obtain different properties from the case of one type.

  The lipid monopeptide is composed of a fatty acid and a monopeptide. As the lipid monopeptide, one composed of a lipid part (alkylcarbonyl group) having a highly fat-soluble chain and a hydrophilic peptide part (monopeptide) represented by the following formula (1) may be used. preferable.

上記式(１)において、
Ｒ¹は、炭素原子数９〜１９の、飽和脂肪族基又は１個の不飽和結合を有する不飽和脂肪族基であり、
Ｒ²は、−（ＣＨ₂）_n−Ｘ基であり、ここで、ｎは１〜４の整数であり、Ｘはアミノ基、グアニジノ基、−ＣＯＮＨ₂基、又は窒素原子を１〜３個有し得る５員環若しくは６員環又は５員環と６員環から構成される縮合複素環であり、
＊が付された炭素は不斉炭素を表し、Ｄ又はＬ配置のいずれかである。

In the above formula (1),
R ¹ is a saturated aliphatic group having 9 to 19 carbon atoms or an unsaturated aliphatic group having one unsaturated bond;
R ² is a — (CH ₂ ) _n —X group, where n is an integer of 1 to 4, and X is an amino group, a guanidino group, a —CONH ₂ group, or 1 to 3 nitrogen atoms. A 5-membered ring or a 6-membered ring or a condensed heterocyclic ring composed of a 5-membered ring and a 6-membered ring,
The carbon marked with * represents an asymmetric carbon and is either D or L configuration.

R ¹ is preferably a saturated aliphatic group having 11 to 17 carbon atoms or an unsaturated aliphatic group having one unsaturated bond. Specific examples of the saturated aliphatic group having 11 to 17 carbon atoms include an undecyl group, a dodecyl group (lauryl group), a tridecyl group, a tetradecyl group (myristyl group), a pentadecyl group, a hexadecyl group (palmityl group), A butadecyl group etc. can be mentioned. Specific examples of the unsaturated aliphatic group having one unsaturated bond having 11 to 17 carbon atoms include an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, a heptadecenyl group, and the like. Can be mentioned.

R ² is a — (CH ₂ ) _n —X group, wherein n is an integer of 1 to 4, and X is preferably an amino group, a guanidino group or a —CONH ₂ group. R ² is a — (CH ₂ ) _n —X group, where n is 1, and X is preferably a pyrrole group, an imidazole group, a pyrazole group or an indole group, and X is an imidazole group. Particularly preferred is a group.

Accordingly, the - (CH ₂₎ As the _n -X group, specifically, aminomethyl group, aminoethyl group, aminopropyl group, 4-aminobutyl group, a carbamoylmethyl group, 2-carbamoyl-ethyl group, A 3-carbamoylbutyl group, a 2-guanidinoethyl group, a 3-guanidinobutyl group, a pyrrolemethyl group, an imidazolemethyl group, a pyrazolemethyl group, or a 3-indolemethyl group can be mentioned, preferably a 4-aminobutyl group, a carbamoylmethyl Group, 2-carbamoylethyl group, 3-guanidinobutyl group, imidazolemethyl group or 3-indolemethyl group, particularly preferably imidazolemethyl group.

In the formula (1), the asymmetric carbon marked with * is preferably L configuration.
Specific examples of the compound of the formula (1) include N-palmitoyl-His, N-nonoyl-His, N-decanoyl-His, N-undecanoyl-His, N-lauroyl-His, N-tridecanoyl-His, N-myristoyl-His, N-pentadecanoyl-His, N-heptadecanoyl-His, N-stearoyl-His, N-nonadecanoyl-His, N-icosanoyl-His, among which N-palmitoyl-His, N-lauroyl-His, N-myristoyl-His, N-stearoyl-His are preferred. The structure of N-palmitoyl-His is shown below.

上記脂質ジペプチドは、脂肪酸とジペプチドから構成される。脂質ジペプチドとしては、下記式(２)で表される、脂溶性の高い鎖を有する脂質部(アルキルカルボニル基)と親水性のペプチド部(ジペプチド)より構成されるものを使用することが好ましい。

The lipid dipeptide is composed of a fatty acid and a dipeptide. As the lipid dipeptide, it is preferable to use one composed of a lipid part (alkylcarbonyl group) having a highly fat-soluble chain and a hydrophilic peptide part (dipeptide) represented by the following formula (2).

上記式(２)において、
Ｒ³は、炭素原子数９〜２３の脂肪族基であり、
Ｒ⁴は、水素原子又は炭素原子数１若しくは２の分枝鎖を有し得る炭素原子数１〜４のアルキル基であり、
Ｒ⁵は、−（ＣＨ₂）_n−Ｘ基を表し、ここで、ｎは１〜４の整数を表し、Ｘはアミノ基、グアニジノ基、−ＣＯＮＨ₂基、又は窒素原子を１〜３個有し得る５員環若しくは６員環又は５員環と６員環から構成される縮合複素環であり、
ａ又はｂが付された炭素は不斉炭素を表し、Ｄ又はＬ配置のいずれかである。

In the above formula (2),
R ³ is an aliphatic group having 9 to 23 carbon atoms,
R ⁴ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a branched chain having 1 or 2 carbon atoms,
R ⁵ represents a — (CH ₂ ) _n —X group, where n represents an integer of 1 to 4, and X represents an amino group, a guanidino group, a —CONH ₂ group, or 1 to 3 nitrogen atoms. A 5-membered ring or a 6-membered ring or a condensed heterocyclic ring composed of a 5-membered ring and a 6-membered ring,
Carbon to which a or b is attached represents an asymmetric carbon and is in either the D or L configuration.

R ³ is preferably a linear saturated aliphatic group having 11 to 21 carbon atoms or a linear unsaturated aliphatic group having 1 or 2 unsaturated bonds, and having 11 to 17 carbon atoms. A linear saturated aliphatic group or a linear unsaturated aliphatic group having one or two unsaturated bonds is particularly preferable. Specific examples of the linear saturated aliphatic group having 11 to 21 carbon atoms include an undecyl group, a dodecyl group (lauryl group), a tridecyl group, a tetradecyl group (myristyl group), a pentadecyl group, and a hexadecyl group (palmityl group). ), Heptadecyl group, octadecyl group (stearyl group), nonadecyl group, icosyl group, henicosyl group, and the like. Specific examples of the linear unsaturated aliphatic group having 1 or 2 unsaturated bonds having 11 to 21 carbon atoms include an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, and a hexadecenyl group. Heptadecenyl group, octadecenyl group, nonadecenyl group, icocenyl group, eicocenyl group, henecocenyl group, henecocenyl group and the like can be mentioned.

Specific examples of R ⁴ include a hydrogen atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, or tert-butyl group. , A methyl group, an isopropyl group, an isobutyl group, or a sec-butyl group is preferable, and a hydrogen atom is particularly preferable.

R ⁵ is a — (CH ₂ ) _n —X group, wherein n is an integer of 1 to 4, and X is preferably an amino group, a guanidino group or a —CONH ₂ group. R ⁵ is a — (CH ₂ ) _n —X group, where n is 1, and X is preferably a pyrrole group, an imidazole group, a pyrazole group or an indole group, and X is an imidazole group. Particularly preferred is a group.

Accordingly, the - (CH ₂₎ As the _n -X group, specifically, aminomethyl group, aminoethyl group, aminopropyl group, 4-aminobutyl group, a carbamoylmethyl group, 2-carbamoyl-ethyl group, A 3-carbamoylbutyl group, a 2-guanidinoethyl group, a 3-guanidinobutyl group, a pyrrolemethyl group, an imidazolemethyl group, a pyrazolemethyl group, or a 3-indolemethyl group can be mentioned, preferably a 4-aminobutyl group, a carbamoylmethyl Group, 2-carbamoylethyl group, 3-guanidinobutyl group, imidazolemethyl group or 3-indolemethyl group, particularly preferably imidazolemethyl group.

Here, R ⁴ is a hydrogen atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group or tert-butyl group, and R ⁵ is amino Methyl group, aminoethyl group, 3-aminopropyl group, 4-aminobutyl group, carbamoylmethyl group, 2-carbamoylethyl group, 3-carbamoylbutyl group, 2-guanidinoethyl group, 3-guanidinobutyl group, pyrrolemethyl group It is also preferable that it is an imidazole methyl group, a pyrazole methyl group or a 3-indolemethyl group.

R ⁴ is a hydrogen atom, methyl group, isopropyl group, isobutyl group or sec-butyl group, and R ⁵ is 4-aminobutyl group, carbamoylmethyl group, 2-carbamoylethyl group, 3-guanidinobutyl. It is also preferred that the group is an imidazole methyl group or a 3-indolemethyl group.

  In the formula (2), the asymmetric carbon to which a is attached is preferably L configuration. In formula (2), the asymmetric carbon to which b is attached is preferably in the L configuration.

  Specific examples of the compound of the formula (2) include N-palmitoyl-Gly-His, N-lauroyl-Gly-His, N-myristoyl-Gly-His, N-margaroyl-Gly-His, N-stearoyl- Gly-His, N-Elidoyl-Gly-His, N-Arachidyl-Gly-His, N-Behenoyl-Gly-His, N-palmitoyl-Ala-His, N-palmitoyl-Val-His, N-palmitoyl-His- Among them, N-palmitoyl-Gly-His, N-lauroyl-Gly-His, N-myristoyl-Gly-His, and N-stearoyl-Gly-His are preferable. The structure of N-palmitoyl-Gly-His is shown below.

本発明の粘度特性改良剤は、上記脂質ペプチドの塩であってもよい。塩としては、特に限定されないが、例えば、ナトリウム塩、カリウム塩、トリフルオロ酢酸塩等を使用できる。

The viscosity characteristic improving agent of the present invention may be a salt of the lipid peptide. Although it does not specifically limit as a salt, For example, a sodium salt, potassium salt, trifluoroacetate salt etc. can be used.

  The blending amount of the viscosity property improver is not particularly limited as long as the kinematic viscosity of the coolant composition at low temperature and high temperature can be within the predetermined range, and is 0 with respect to 100 parts by mass of the composition The amount is preferably 0.05 to 4.5 parts by mass, particularly preferably 0.1 to 0.5 parts by mass. In the coolant composition of the present invention, the above various viscosity characteristic improvers can be used in combination.

The coolant composition of the present invention has a kinematic viscosity of 8.5 mm ² / sec or more at 25 ° C. and 2.0 mm ² / sec or less at 100 ° C.
The coolant composition of the present invention has a kinematic viscosity at 25 ° C. of 8.5 mm ² / sec or more, preferably 8.5 to 3000 mm ² / sec, particularly preferably 10 to 2000 mm ² / sec, and particularly preferably 17. Since it is as high as 5 to 1000 mm ² / sec, the heat dissipation at low temperatures is low and the cooling loss is low. When the kinematic viscosity at 25 ° C. is 3000 mm ² / sec or less, the coolant composition of the present invention is preferable in that it can avoid a load on the water pump and prevent deterioration of fuel consumption of the internal combustion engine. Moreover, since the kinematic viscosity in 25 degreeC is 8.5 mm < ² > / sec or more, the cooling fluid composition of this invention has a kinematic viscosity higher than the conventional 80% ethylene glycol cooling fluid. The ethylene glycol coolant cannot be used as a coolant because the flash point is generated when the ethylene glycol concentration exceeds 80%.

The coolant composition of the present invention has a kinematic viscosity at 100 ° C. of 2.0 mm ² / sec or less, preferably 0.3 to 2.0 mm ² / sec, particularly preferably 0.3 to 1.5 mm ² / sec. Since it is low, the cooling capability at a high temperature is maintained, and overheating can be prevented. The cooling capacity of the cooling liquid composition can be evaluated, for example, by measuring the radiator heat transmittance. The kinematic viscosity at 100 ° C. of a 100% water coolant is 0.3 mm ² / sec.

  The coolant composition of the present invention preferably contains a base having antifreezing properties. The compounding amount of the base is preferably 86 to 99.99 parts by mass and particularly preferably 94.5 to 99.9 parts by mass with respect to 100 parts by mass of the composition.

  The base contains at least one alcohol selected from the group consisting of monohydric alcohols, dihydric alcohols, trihydric alcohols and glycol monoalkyl ethers and / or water. If antifreeze is not required, the base may be water alone.

  As monohydric alcohol, what consists of 1 type, or 2 or more types of mixtures chosen from methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, and octanol, for example can be mentioned.

  Examples of the dihydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, and hexylene glycol. What consists of 1 type, or 2 or more types of mixtures chosen from among these can be mentioned.

  Examples of the trihydric alcohol include one or more selected from glycerin, trimethylolethane, trimethylolpropane, 5-methyl-1,2,4-heptanetriol, and 1,2,6-hexanetriol. The thing which consists of a mixture can be mentioned.

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

  Among the above bases, ethylene glycol, propylene glycol, and 1,3-propanediol are preferable from the viewpoints of handleability, cost, and availability.

  The blending amount of the alcohols is preferably 8.55 to 98.85 parts by mass with respect to 100 parts by mass of the composition in consideration of antifreezing properties, and 21.38 to 98.85 parts by mass. Is particularly preferred.

  The base may further contain water, and the water is preferably ion-exchanged water. The blending amount of water is preferably 0.86 to 89.87 parts by mass, particularly preferably 0.86 to 74.89 parts by mass with respect to 100 parts by mass of the composition. When the base contains water and alcohols, the mixing ratio of water and alcohols can be arbitrarily adjusted in consideration of antifreezing and flammability. The ratio of water and alcohol in the base is preferably 20:80 to 90:10, particularly preferably 40:60 to 75:25, from the viewpoint of avoiding the flash point. .

  In the cooling liquid composition of the present invention, other additives can be blended with the base as needed within the range not impairing the effects of the present invention, in addition to the viscosity property improving agent.

  In order to effectively suppress corrosion of the metal used in the engine coolant path, the coolant composition of the present invention contains at least one rust preventive agent in a range that does not affect kinematic viscosity. be able to. Examples of rust preventives include phosphoric acid and / or salts thereof, aliphatic carboxylic acids and / or salts thereof, aromatic carboxylic acids and / or salts thereof, triazoles, thiazoles, silicates, nitrates, nitrites, boron Any one or a mixture of two or more of acid salts, molybdates and amine salts can be mentioned.

  Further, in the cooling liquid composition of the present invention, at least one or more dispersants (or solubilizers) are used in order to solubilize lipid peptides and disperse them more uniformly in the base and to control kinematic viscosity more precisely. Agent). As the dispersant (or solubilizer), any one or two of polyoxyethylene styrenated phenyl ether, polyoxyethylene alkyl ether, sodium naphthalene sulfonate formalin condensate, polyoxyethylene polyoxypropylene glycol and acrylic copolymer Mention may be made of mixtures of more than one species.

  In addition, for example, a pH adjuster such as sodium hydroxide or potassium hydroxide, an antifoaming agent, a colorant, or a dye may be appropriately added to the cooling liquid composition of the present invention as long as the kinematic viscosity is not affected. it can.

  The total amount of the other additives is usually 10 parts by mass or less, preferably 5 parts by mass or less, with respect to 100 parts by mass of the composition.

  The coolant composition of the present invention can be used as a coolant for an internal combustion engine.

The present invention also relates to a concentrated composition for obtaining the coolant composition. The concentrated composition of the present invention is a composition comprising the above-mentioned viscosity property improving agent and the above-mentioned base. The cooling liquid composition of the present invention can be obtained by adding the remaining base and optionally other additives to the concentrated composition of the present invention. The base contained in the concentrated composition of the present invention may be the same as or different from the base further added to obtain the coolant composition. The concentrated composition of the present invention preferably contains 0.1 to 99.9 parts by mass of the above-mentioned viscosity characteristic improving agent with respect to 100 parts by mass of the concentrated composition, and the above-mentioned base with respect to 100 parts by mass of the concentrated composition. It is preferable to contain 1-99.9 mass parts.
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to the range of an Example.

[Example 1]
47.4 parts by mass of ethylene glycol and 50 parts by mass of ion-exchanged water were mixed, and 2 parts by mass of disodium sebacate as a rust inhibitor and polyoxyethylene styrenated phenyl ether as a dispersant [Daiichi Kogyo Seiyaku Co., Ltd. 0.5 parts by mass of Neugen EA197, manufactured by company, was added and mixed. After adding 0.1 part by mass of N-palmitoyl-His (L configuration) as a lipid monopeptide to the obtained mixture, the mixture was heated to 80 ° C., then stirred for 30 minutes, stirred and cooled. As a result, a coolant composition was obtained.

[Example 2]
44 parts by mass of ethylene glycol is used instead of 47.4 parts by mass of ethylene glycol, 46 parts by mass of ion-exchanged water is used instead of 50 parts by mass of ion-exchanged water, and the dispersant is used instead of 0.5 part by mass of the dispersant. A coolant composition was obtained in the same manner as in Example 1 except that 4 parts by mass and 4 parts by mass of N-palmitoyl-His were used instead of 0.1 parts by mass of N-palmitoyl-His.

[Example 3]
Cooling was carried out in the same manner as in Example 1 except that 0.1 part by mass of N-palmitoyl-Gly-His (His portion was L-arranged) as a lipid dipeptide was used instead of 0.1 part by mass of N-palmitoyl-His. A liquid composition was obtained.

[Example 4]
44 parts by mass of ethylene glycol is used instead of 47.4 parts by mass of ethylene glycol, 46 parts by mass of ion-exchanged water is used instead of 50 parts by mass of ion-exchanged water, and the dispersant is used instead of 0.5 part by mass of the dispersant. A coolant composition was obtained in the same manner as in Example 1 except that 4 parts by mass and 4 parts by mass of N-palmitoyl-Gly-His were used instead of 0.1 parts by mass of N-palmitoyl-His.

[Comparative Example 1]
A coolant composition was obtained in the same manner as in Example 1 except that 48 parts by mass of ethylene glycol was used instead of 47.4 parts by mass of ethylene glycol, and the dispersant and N-palmitoyl-His were not used. . The coolant composition of Comparative Example 1 corresponds to a conventional 50% ethylene glycol coolant, and was used as a reference when evaluating warm-up performance and cooling performance.

[Comparative Example 2]
A coolant composition was prepared in the same manner as in Example 1 except that ethylene glycol, a dispersant and N-palmitoyl-His were not used, and 98 parts by mass of ion-exchanged water was used instead of 50 parts by mass of ion-exchanged water. Obtained. The cooling liquid composition of Comparative Example 2 corresponds to a conventional cooling liquid with water as a base and high cooling performance.

[Comparative Example 3]
47.8 parts by mass of ethylene glycol is used instead of 47.4 parts by mass of ethylene glycol, no dispersant is used, and 0.2 part by mass of carboxyvinyl polymer is used instead of 0.1 part by mass of N-palmitoyl-His A coolant composition was obtained in the same manner as in Example 1 except that.

[Comparative Example 4]
47.998 parts by mass of ethylene glycol is used in place of 47.4 parts by mass of ethylene glycol, 0.001 part by mass of dispersant is used in place of 0.5 part by mass of dispersant, 0.1 mass of N-palmitoyl-His A coolant composition was obtained in the same manner as in Example 1 except that 0.001 part by mass of N-palmitoyl-His was used instead of the part.

[Comparative Example 5]
38 parts by mass of ethylene glycol is used instead of 47.4 parts by mass of ethylene glycol, 40 parts by mass of ion exchange water is used instead of 50 parts by mass of ion exchange water, and a dispersant is used instead of 0.5 part by mass of the dispersant. A coolant composition was obtained in the same manner as in Example 1 except that 10 parts by mass was used and 10 parts by mass of N-palmitoyl-His was used instead of 0.1 parts by mass of N-palmitoyl-His.

[Comparative Example 6]
47.998 parts by mass of ethylene glycol is used in place of 47.4 parts by mass of ethylene glycol, 0.001 part by mass of dispersant is used in place of 0.5 part by mass of dispersant, 0.1 mass of N-palmitoyl-His A coolant composition was obtained in the same manner as in Example 1 except that 0.001 part by mass of N-palmitoyl-Gly-His was used instead of the part.

[Comparative Example 7]
38 parts by mass of ethylene glycol is used instead of 47.4 parts by mass of ethylene glycol, 40 parts by mass of ion exchange water is used instead of 50 parts by mass of ion exchange water, and a dispersant is used instead of 0.5 part by mass of the dispersant. A coolant composition was obtained in the same manner as in Example 1 except that 10 parts by mass was used and 10 parts by mass of N-palmitoyl-His was used instead of 0.1 parts by mass of N-palmitoyl-Gly-His.

  The kinematic viscosities at 25 ° C. and 100 ° C. of the coolant compositions obtained in Example 1-4 and Comparative Example 1-7 were measured, and the thermal characteristics (warming-up performance and cooling performance) were evaluated.

<Measurement of kinematic viscosity>
The kinematic viscosity at 25 ° C. and 100 ° C. of the coolant composition is JIS K 2283 or ASTM D445. The measurement was performed according to a test method using a D446 glass capillary viscometer. Specifically, it measured by the following method.
(1) A Ubbelohde viscometer defined in JIS K 2283 was prepared, and a specified amount of the sample was filled while being tilted so that bubbles did not enter.
(2) The viscometer filled with the sample was conditioned in a constant temperature water bath for 15 minutes.
(3) The sample was sucked up to the upper time mark and then naturally dropped, and the time for the meniscus to pass from the upper part to the lower part of the time mark was measured.
(4) When the measurement time was less than 200 seconds, the viscometer was replaced and the operations (1) to (3) were performed.
(5) When the measurement is performed twice using a viscometer with a measurement time of 200 seconds or more, and the difference in the measurement time is within 0.2% of the average value, the average measurement time and the viscometer used The kinematic viscosity was calculated from the viscometer constant.

<Warm-up performance>
The warm-up performance was measured using a simple thermal property evaluation test apparatus (see FIG. 2) at room temperature of 25 ° C., and the time until the aluminum casting was heated from 25 ° C. to 60 ° C. was measured. The result of Comparative Example 1 (240 seconds) was set to a reference value of 1.0.

<Cooling performance>
The warm-up performance was measured using a simple thermal property evaluation test apparatus (see FIG. 2) at room temperature of 25 ° C., and the time until the aluminum casting was cooled from 90 ° C. to 80 ° C. was measured. The result of Comparative Example 1 (300 seconds) was taken as the reference value 1.0.

  Table 1 shows the measurement results of the kinematic viscosity, warm-up performance, and cooling performance of the coolant compositions obtained in Example 1-4 and Comparative Example 1-7.

  From Table 1, the coolant composition of Example 1-4 has a high kinematic viscosity at low temperatures and a sufficient decrease in kinematic viscosity at high temperatures. It can be seen that the warm-up performance is further improved and the cooling performance is maintained. In particular, Example 4 has improved warm-up performance.

  It can be seen that the cooling liquid compositions of Comparative Examples 3, 5 and 7 have high warm-up performance, but are inferior in cooling performance due to small decrease in kinematic viscosity at high temperatures. On the other hand, the cooling liquid composition of Comparative Example 2 has high cooling performance, but has a low kinematic viscosity at low temperatures and is inferior in warm-up performance.

  It can be seen that the cooling liquid compositions of Comparative Examples 4 and 6 do not have an effect as a viscosity property improving agent because the lipid peptide content is not sufficient.

  The coolant composition of the present invention is suitable for cooling vehicles such as automobiles, working vehicles (trucks, heavy machinery, etc.), ships, airplanes, generators, internal combustion engines (including hybrid systems) for cooling and heating systems, batteries, and inverters. Used for.

Claims (9)

A lipid peptide or a salt thereof as a viscosity property improver, and a base,
The lipid peptide is a lipid monopeptide composed of a fatty acid and a monopeptide and / or a lipid dipeptide composed of a fatty acid and a dipeptide,
The base contains at least one alcohol selected from the group consisting of monohydric alcohols, dihydric alcohols, trihydric alcohols and glycol monoalkyl ethers and / or water;
A coolant composition having a kinematic viscosity of 8.5 mm ² / sec or more at 25 ° C. and 2.0 mm ² / sec or less at 100 ° C. The lipid peptide has the formula (1):

[Where:
R ¹ is a saturated aliphatic group having 9 to 19 carbon atoms or an unsaturated aliphatic group having one unsaturated bond;
R ² is a — (CH ₂ ) _n —X group, where n is an integer of 1 to 4, and X is an amino group, a guanidino group, a —CONH ₂ group, or 1 to 3 nitrogen atoms. A 5-membered ring or a 6-membered ring or a condensed heterocyclic ring composed of a 5-membered ring and a 6-membered ring,
Carbon marked with * represents an asymmetric carbon and is either D or L configuration]
The cooling fluid composition according to claim 1, which is a lipid monopeptide represented by the formula: n is an integer of 1 to 4 and X is an amino group, guanidino group or —CONH ₂ group, or n is 1, and X is a pyrrole group, imidazole group, pyrazole group or indole group The coolant composition according to claim 2.   The coolant composition according to claim 2 or 3, wherein the asymmetric carbon marked with * is in L configuration. The lipid peptide is of formula (2):

[Where:
R ³ is a linear saturated aliphatic group having 9 to 23 carbon atoms or a linear unsaturated aliphatic group having 1 or 2 unsaturated bonds,
R ⁴ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a branched chain having 1 or 2 carbon atoms,
R ⁵ represents a — (CH ₂ ) _n —X group, where n represents an integer of 1 to 4, and X represents an amino group, a guanidino group, a —CONH ₂ group, or 1 to 3 nitrogen atoms. A 5-membered ring or a 6-membered ring or a condensed heterocyclic ring composed of a 5-membered ring and a 6-membered ring,
Carbon to which a or b is attached represents an asymmetric carbon and is in either the D or L configuration]
The coolant composition according to any one of claims 1 to 4, which is a lipid dipeptide represented by the formula: n is an integer of 1 to 4 and X is an amino group, guanidino group or —CONH ₂ group, or n is 1, and X is a pyrrole group, imidazole group, pyrazole group or indole group The coolant composition according to claim 5. R ⁴ is a hydrogen atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group or tert-butyl group, and R ⁵ is an aminomethyl group, Aminoethyl, 3-aminopropyl, 4-aminobutyl, carbamoylmethyl, 2-carbamoylethyl, 3-carbamoylbutyl, 2-guanidinoethyl, 3-guanidinobutyl, pyrrolemethyl, imidazolemethyl The coolant composition according to claim 5 or 6, which is a group, a pyrazolemethyl group or a 3-indolemethyl group.   The coolant composition according to any one of claims 5 to 7, wherein the asymmetric carbon to which a is attached is in an L configuration.   The coolant composition according to any one of claims 1 to 8, wherein the viscosity characteristic improver is contained in an amount of 0.05 to 4.5 parts by mass with respect to 100 parts by mass of the composition.

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