Novel coolant compositions
By using a formulation of water, alkylene glycols, and glycerin in the coolant, and adding appropriate amounts of polyethyleneimine and carboxylic acid, the problem of high conductivity caused by low molecular weight amine inhibitors was solved, achieving both low conductivity and good corrosion inhibition.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BASF SE
- Filing Date
- 2024-11-19
- Publication Date
- 2026-06-19
AI Technical Summary
The low molecular weight amine corrosion inhibitors used in existing coolants result in high electrical conductivity, which is difficult to meet the low electrical conductivity requirements of electric vehicles. At the same time, traditional inhibitors have limited corrosion protection effects on certain metals.
A coolant formulation containing at least 40% water, 30% alkylene glycols and glycerin, combined with 0.1% to 5% polyethyleneimine and carboxylic acid, optimizes the component ratio to reduce conductivity and improve corrosion inhibition.
It achieves effective corrosion inhibition of metals under low conductivity, especially protection of aluminum, while maintaining good corrosion protection effect.
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Abstract
Description
[0001] This invention describes a novel coolant composition for a cooling system comprising at least one polymer containing at least one polyethyleneimine.
[0002] The coolant according to the invention can be used in cooling systems for stationary motors or in vehicles having an internal combustion engine, an electric motor, a fuel cell, or in hybrid engines having a combination of an internal combustion engine and an electric motor or a combination of an internal combustion engine and a fuel cell, or in generators, such as wind turbines.
[0003] The diol compounds that lower the freezing point are typically monoethylene glycol and / or monopropylene glycol, with monoethylene glycol being the primary component.
[0004] In addition, coolants typically contain at least one inhibitor, usually a mixture of inhibitors, to protect the metals commonly used in the cooling system from corrosion. Typical metals include, for example, ferrous materials, aluminum and its alloys, copper, and brass. The inhibitors used in coolants usually have corrosion-inhibiting effects on one or more of these materials, but not on all of them. For this reason, several inhibitors are usually used to protect typical materials from corrosion.
[0005] Low molecular weight amines, such as alkylamines or ethanolamines, such as triethanolamine, butyl diethanolamine or octyl diethanolamine, are often used as corrosion inhibitors, especially for iron-containing materials.
[0006] These amines have relatively high basicity, and therefore high degree of dissociation, which increases the conductivity of the coolant. However, especially for electric vehicles, low conductivity is sought to avoid short circuits in the event of coolant leakage and contact with the battery.
[0007] A fundamental challenge in developing low-conductivity radiator protectants is that most corrosion inhibitors used are ionic. Consequently, conventional radiator protectants are found to have conductivity values in the hundreds of thousands of µS / cm. Typical corrosion inhibitors are inorganic salts, such as nitrites, nitrates, silicates, and phosphates, which significantly contribute to conductivity. Organic corrosion inhibitors are carboxylic acids, which exist as carboxylates in the typical pH environment of radiator protectants, thus also contributing to high conductivity.
[0008] US 2018 / 0100239 A1 describes the suppression of corrosion on metal surfaces by treatment with an aqueous solution of polyethyleneimine.
[0009] Since poly(meth)acrylic acid is often used as a corrosion inhibitor for metal surfaces, but it forms an acid-base salt with polyethyleneimine, the simultaneous use of poly(meth)acrylic acid and polyethyleneimine is prohibited, and therefore it is preferably excluded according to US 2018 / 0100239 A1.
[0010] One object of this invention is to replace low molecular weight amines in coolants with other compounds that exhibit at least the same level of corrosion inhibition but show lower electrical conductivity in coolants. Another object of this invention is to identify typical materials for cooling circuits, particularly nonionic corrosion inhibitors for aluminum, that exhibit good corrosion protection while having low electrical conductivity.
[0011] This objective is addressed by the coolant, which includes...
[0012] - At least 40% by weight water (A)
[0013] - At least 30% by weight of alkylene glycols, alkylene glycol monoalkyl ethers and glycerol (B).
[0014] -0.1% to 5% by weight of at least one acid selected from the group consisting of:
[0015] --(C2a)benzoic acid is an aromatic monocarboxylic acid.
[0016] -- (C2b) at least one aliphatic monocarboxylic acid, and
[0017] -- (C3) At least one organic dicarboxylic acid having 4 to 20 carbon atoms,
[0018] - At least 0.01% to 5% by weight of at least one polyethyleneimine (F).
[0019] Surprisingly, the simultaneous use of carboxylic acid and polyethyleneimine (F) resulted in corrosion inhibition while maintaining acceptable electrical conductivity.
[0020] Polyethyleneimine (F)
[0021] In this context, polyethyleneimine (F) is understood as a compound containing one or more substructures >N-CH2-CH2-N< as repeating units.
[0022] Polyethyleneimine is preferably selected from the group consisting of formula (I).
[0023]
[0024] Japanese style (II)
[0025]
[0026] in,
[0027] x and y independently represent 0 (zero) or a positive integer, provided that
[0028] - In equation (II), the sum of x and y is not 0 (zero).
[0029] For each x, the substituent on the nitrogen atom is -CH2-CH2-[-NH-CH2-CH2-]. y -NH2 can have different y values.
[0030] x is preferably at least 1, particularly preferably at least 2, very particularly preferably at least 3, especially at least 5, and especially at least 10.
[0031] y is preferably at least 1, particularly preferably at least 2, very particularly preferably at least 3, especially at least 5, and especially at least 10.
[0032] The upper limits of x and y can be independent of each other and are up to 1500, preferably up to 1400, particularly preferably up to 1300, very particularly preferably up to 1200, especially up to 1000, and especially up to 750.
[0033] pass 13 The ratio of primary nitrogen atoms to secondary nitrogen atoms to tertiary nitrogen atoms in polyethyleneimine, as determined by C-NMR spectroscopy, is preferably 1:0.5 to 1.5:0.3 to 0.9, more preferably 1:0.6 to 1.3:0.4 to 0.8, more preferably 1:0.7 to 1.3:0.4 to 0.8, and particularly 1:0.9 to 1.1:0.5 to 0.8.
[0034] Those skilled in the art know suitable methods for preparing polyethyleneimine by polymerization of ethylenimine (aziridine).
[0035] Polyethyleneimine is preferably prepared by cationic ring-opening polymerization of ethylimine in the presence of Broensted acid, Lewis acid, haloalkanes, or carbon dioxide. Examples can be found in US 2,182,306 and US 3,203,910 and US Patent US2001 / 0039318.
[0036] For further reference as a further example of polyethylene synthesis, see “Zaziridine and aziridine: structural units of polyamines via anionic and cationic ring-opening polymerization” Gleede, T.; Reisman, L.; Rieger, E.; Mbarushimana, PC; Ru-par, PA; Wurm, FR; Polymer Chemistry 2019, 10, 3257.
[0037] The polymerization can be carried out, for example, in a batch process, in which water and 1,2-dichloroethane are introduced into the reaction vessel as catalysts, the mixture is heated to a temperature of 70°C to 100°C, and ethyleneimine is continuously added while the reaction mixture is stirred.
[0038] The resulting polyethyleneimine is usually branched or hyperbranched polyethyleneimine.
[0039] In this way, polyethyleneimine with a weight-average molecular weight Mw in the range of 500 g / mol to 2,000,000 g / mol, preferably in the range of 500 g / mol to 100,000 g / mol, can be obtained.
[0040] As a polymer, it has a molecular weight distribution. In the context of this specification, polyethyleneimine (F) with a weight-average molecular weight (Mw as measured by GPC) of less than 55,000 g / mol, more preferably less than 40,000 g / mol, even more preferably less than 30,000 g / mol, and even more preferably less than 15,000 g / mol is preferred. In a preferred embodiment, the weight-average molecular weight Mw is at least 500 g / mol, preferably at least 750 g / mol, and very particularly preferably at least 1000 g / mol. The flow number x in formula (I) or the sum (x+y) in formula (II) is selected such that polyethyleneimines with these molecular weights are obtained, i.e., preferably from 11 to 930, particularly preferably from 17 to 700, and very particularly preferably from 23 to 350. Idealized formulas (I) and (II) illustrate the structure of branched polyethyleneimine, wherein the average ratio of primary nitrogen atoms, secondary nitrogen atoms, and tertiary nitrogen atoms is about 1:2:1. The preferred polyethyleneimine has the above-mentioned preferred ratio of primary nitrogen atoms to secondary and tertiary nitrogen atoms.
[0041] coolant
[0042] Therefore, the present invention relates to an aqueous coolant comprising at least one component selected from the group consisting of alkylene glycols, alkylene glycol monoalkyl ethers and glycerol, preferably monoethylene glycol and / or monopropylene glycol, particularly preferably monoethylene glycol, and at least one polyethyleneimine (F) as described above as an ethylene glycol component for lowering the freezing point.
[0043] These are particularly preferred coolants, containing
[0044] - At least 40% to 90% by weight, preferably 45% to 80% by weight, particularly preferably 50% to 70% by weight of water (A).
[0045] - At least 30% to 60% by weight, preferably 35% to 55% by weight, particularly preferably 40% to 50% by weight of alkylene glycols, alkylene glycol monoalkyl ethers and glycerol (B).
[0046] As an inhibitor (C)
[0047] - (C1) Optionally selected from at least one inorganic compound consisting of silicates, borates, nitrates, molybdates and phosphates.
[0048] -(C2a) benzoic acid, optionally an aromatic monocarboxylic acid
[0049] -(C2b) optionally at least one aliphatic monocarboxylic acid,
[0050] - (C3) Optionally at least one organic dicarboxylic acid having 4 to 20 carbon atoms
[0051] - (C4) at least 0.005% to 5% by weight, preferably at least 0.0075% to 2.5% by weight, particularly preferably at least 0.01% to 1% by weight of at least one azole compound, preferably at least one triazole compound.
[0052] - (C5) optionally at least one organic amine,
[0053] - (D) Optionally at least one inorganic base
[0054] - (E) Optionally, at least one other ingredient is selected from the group consisting of hard water stabilizers, defoamers, colorants and bittering agents.
[0055] -0.01% to 5% by weight, preferably 0.05% to 4% by weight, particularly preferably 0.1% to 3% by weight of at least one polyethyleneimine (F).
[0056] The premise is that the sum of all components is always 100 by weight.
[0057] If an inorganic compound (C1) is included in the coolant according to the invention, it is present in an amount of 0.1% to 5% by weight, preferably 0.2% to 4% by weight, and particularly preferably 0.25% to 3% by weight in each case.
[0058] In a preferred embodiment, the coolant, concentrate, or ultra-concentrate according to the invention does not contain inorganic compounds (C1).
[0059] If acids (C2a), (C2b) and / or (C3) are present in the coolant according to the invention, they are present in an amount of 0.1% to 5% by weight, preferably 0.2% to 4% by weight, and particularly preferably 0.25% to 3% by weight in each case.
[0060] Among the acids (C2a), (C2b) and (C3), aliphatic monocarboxylic acids (C2b) and organic dicarboxylic acids (C3) are preferred, especially aliphatic monocarboxylic acids (C2b).
[0061] To minimize the formation of ion-forming substances, the molar ratio of the tertiary amino group in polyethyleneimine (F) and optionally the organic amine (C5) (total) to the acid (C2a), (C2b) and (C3) (total) is preferably 1:0.01 to 1:0.5, particularly preferably 0.02 to 0.4, very particularly preferably 0.05 to 0.3, especially 0.05 to 0.25, and especially 0.075 to 0.2.
[0062] If the inorganic base (D) is included in the coolant according to the invention, it is present in an amount of 0.1% to 5% by weight, preferably 0.2% to 4% by weight, and particularly preferably 0.25% to 3% by weight in each case.
[0063] Components
[0064] (A) Water
[0065] The water used within the framework of this invention should be neutral, with a pH value of around 7. This can be deionized water or distilled water, but this is not mandatory. To also enable the use of hard water, the compositions of this invention typically contain at least one hard water stabilizer (see below).
[0066] (B) Alkylene glycols, alkylene glycol monoalkyl ethers, and glycerol
[0067] Component (B) causes the main freezing point decrease in the coolant.
[0068] Component (B) preferably contains at least a portion of monoethylene glycol and / or monopropylene glycol, with monoethylene glycol being more preferred.
[0069] In addition to monoethylene glycol and / or monopropylene glycol, component (B) may also contain other alkylene glycols, alkylene glycol monoalkyl ethers or glycerol.
[0070] However, in a preferred embodiment of the invention, component (B) consists only of monoethylene glycol and / or monopropylene glycol, preferably monoethylene glycol. For the purposes of preparation, these compounds may contain small amounts of higher homologues of the corresponding alkylene glycols, such as diethylene glycol or dipropylene glycol.
[0071] The individual components (B) are monomers to tetramers of 1,2-ethylene glycol, 1,2-propanediol, or more rarely 1,3-propanediol, preferably monomers to trimers of 1,2-ethylene glycol or 1,2-propanediol, particularly preferably monomers or dimers of 1,2-ethylene glycol, very particularly preferably monomers of 1,2-ethylene glycol, and in each case mixtures thereof.
[0072] The alkylene glycol monoalkyl ether is a monoC1-C4 alkyl ether of the above-mentioned alkylene glycol, preferably a monomethyl ether, a monoethyl ether or a n-butyl ether, particularly preferably a monomethyl ether or a n-butyl ether, and especially preferably a monomethyl ether.
[0073] In addition, glycerol or glycerol oligomers are possible components (B).
[0074] Preferred alkylene glycol components or derivatives are particularly ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and mixtures thereof; in addition, propylene glycol, dipropylene glycol, and mixtures thereof are used alone or in mixtures; polyethylene glycol; glycol ethers, such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol monoethyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol mono-n-butyl ether, tetraethylene glycol mono-n-butyl ether, or glycerol.
[0075] Particularly preferred is the use of monoethylene glycol alone or a mixture of monoethylene glycol as the main component with other alkylene glycols or alkylene glycol derivatives, wherein the main component is defined as having a content of more than 50% by weight, particularly more than 80% by weight, and especially more than 95% by weight in the mixture.
[0076] When monoethylene glycol is used as a compound to lower the freezing point, the content of higher ethylene glycol oligomers, namely diethylene glycol, triethylene glycol, etc., is less than 5% by weight, preferably less than 2.5% by weight, particularly preferably less than 1% by weight, and very particularly preferably less than 0.5% by weight.
[0077] Industrially, monoethylene glycol is typically prepared by the ring-opening reaction of ethylene oxide with water, where ethylene oxide is produced from ethylene, which in turn is obtained by cracking naphtha in a steam cracker.
[0078] It is also conceivable to add renewable feedstock-based starting materials to the fossil fuel inflow in a steam pyrolyzer, resulting in ethylene with a certain proportion of bio-based content. For monoethylene glycol obtained in this way, this means a portion of fossil-based monoethylene glycol and a portion of bio-based monoethylene glycol.
[0079] In another embodiment, monoethylene glycol may be obtained partially or entirely, preferably entirely, from renewable feedstocks.
[0080] Monoethylene glycol obtained from renewable feedstocks can be determined by... 14 C / 12 Characterized by carbon isotope ratio, preferably determined according to ASTM D 6866 ("Determination of bio-based content in natural range materials using radiocarbon and isotope ratio mass spectrometry").
[0081] According to this test method, the sample's... 14 C / 12 C isotope ratio, and compared with that in standardized 100% bio-based materials. 14 C / 12 The carbon isotope ratios were compared. As a result, the proportion of bio-based components in the samples was obtained.
[0082] This indicator is given as a percentage in "pMC" (percentage of modern carbon). If the material being analyzed is a mixture of modern radioactive carbon and fossil carbon (containing trace amounts of radioactive carbon), the obtained pMC value is directly related to the amount of biomass material present in the sample.
[0083] "Bio-based materials" are organic materials whose carbon originates from CO2 fixed from the atmosphere via solar energy (photosynthesis) in the recent past (measured on a human timescale). On land, this CO2 is absorbed or fixed by plants (such as agricultural crops or forestry plantations). In the ocean, this CO2 is bound or fixed by the photosynthesis of bacteria or phytoplankton. Therefore, bio-based materials have a carbon content greater than 0. 14 C / 12 C isotope ratio. In contrast, fossil materials have a ratio of approximately 0. 14 C / 12 C isotope ratio.
[0084] In a preferred embodiment, the monoethylene glycol used in the coolant according to the invention has a bio-based content of greater than 0%, preferably at least 1%, particularly preferably at least 5%, very particularly preferably at least 10%, especially at least 20%, and particularly at least 25%, in accordance with ASTM-D6866. 14 C: 12 C-ratio measurement.
[0085] Advantageously, the bio-based content can be at least 30%, preferably at least 40%, particularly preferably at least 50%, especially preferably at least 66%, particularly at least 75%, and especially at least 85%.
[0086] When the proportion is at least 90%, preferably at least 95%, particularly preferably at least 98%, or even 100%, it can be called a monoethylene glycol with significant advantages or completely bio-based.
[0087] The monoethylene glycol used in the coolant can be obtained entirely from renewable raw materials, or it can consist of a mixture of monoethylene glycol from renewable and fossil sources.
[0088] The possibility of preparing such bio-based monoethylene glycol is described in an unpublished European patent application (file number 23185804.4, filed on July 17, 2023) or an unpublished international patent application (file number PCT / EP2024 / 069303, filed on July 9, 2024).
[0089] Inhibitor (C)
[0090] Inhibitors (C) act as corrosion inhibitors for metals such as ferrous materials, aluminum, non-ferrous metals, or solders.
[0091] The compositions according to the present invention comprise at least one of the following inhibitors:
[0092] - (C1) Optionally at least one inorganic compound and organosilicon ester selected from the group consisting of silicates, borates, nitrates, molybdates and phosphates.
[0093] -(C2a) benzoic acid, optionally an aromatic monocarboxylic acid
[0094] - (C2b) optionally at least one aliphatic monocarboxylic acid
[0095] - (C3) Optionally at least one organic dicarboxylic acid having 4 to 20 carbon atoms
[0096] - (C4) At least one azole, preferably at least one triazole compound,
[0097] - (C5) Optionally at least one organic amine.
[0098] Inorganic inhibitors (C1)
[0099] Inorganic inhibitors (C1) are silicates, borates, nitrates, molybdates, or phosphates, or mixtures thereof in their free acid or salt form, particularly their alkali metal salts, especially their sodium or potassium salts. The form in which they are present in the composition, super-concentrate, concentrate, or coolant depends on the corresponding pK of the compound and the composition. s The pH value and the corresponding environmental pH value, which is determined by the amount of base (D).
[0100] Inorganic silicates primarily function as inhibitors of aluminum corrosion, and are typically used as alkali metal salts or, more rarely, as magnesium, calcium, or aluminum salts, preferably as sodium or potassium salts.
[0101] Silicates are preferably free silicates (SiO4) 4- ), metasilicate (SiO3) 2- ) and pyrosilicon (Si2O7) 6-The group consisting of, particularly preferably, metasilicates (SiO3) 2- The preferred materials are sodium metasilicate (Na2SiO3) or potassium metasilicate (K2SiO3), especially sodium metasilicate (Na2SiO3).
[0102] If the composition according to the invention contains at least one inorganic silicate or organosilicon ester, in a preferred embodiment, at least one phosphonosilicate, as described in EP 4015596 or WO 2022 / 043303 regarding silicates, is added in addition to the silicate.
[0103] Preferably, the phosphosilicate is a compound of the following general formula:
[0104]
[0105] in,
[0106] R 5 It is a divalent organic group, preferably a 1,ω-alkylene group having 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, particularly methylene, 1,2-ethylene, 1,2-propylene, 1,3-propylene or 1,4-butylene, especially 1,2-ethylene or 1,3-propylene, particularly 1,2-ethylene.
[0107] R 6 Each of the following is independently hydrogen, C1 to C4 alkyl or hydroxy-C2-C4 alkyl, preferably hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl, 2-hydroxyethyl or 2-hydroxypropyl, and particularly preferably hydrogen, methyl, ethyl or propyl.
[0108] And R 7 It is a C1 to C4 alkyl group, preferably methyl, ethyl, n-propyl or n-butyl, particularly methyl, ethyl or n-butyl, especially methyl or ethyl, particularly methyl.
[0109] Silicates can be used in the form of free acid or alkali metal salt, preferably in the form of sodium or potassium salt, and particularly preferably in the form of sodium salt.
[0110] The borates are preferably used in the form of sodium tetraborate (borax) or potassium tetraborate, and particularly preferably in the form of sodium tetraborate.
[0111] Nitrates are used in the form of alkali metal or alkaline earth metal nitrates, preferably in the form of sodium nitrate, potassium nitrate or magnesium nitrate, and particularly preferably in the form of sodium nitrate.
[0112] Phosphates are used in the form of free acid (H3PO4), hydrogen phosphate, dihydrogen phosphate, or phosphate, preferably in the form of sodium or potassium salts.
[0113] It is also conceivable to use the corresponding diphosphate, triphosphate, or oligophosphate, but preferably in the form of monomeric phosphate.
[0114] It is preferably used in the form of free acid (H3PO4), disodium hydrogen phosphate or trisodium phosphate.
[0115] Orthosilicates are compounds with the following molecular formulas.
[0116] Si(OR 1 )4
[0117] in,
[0118] R 1 The organic substituent is an organic substituent having 1 to 6 carbon atoms, such as a straight chain or a branched chain, preferably a straight-chain alkyl substituent having 1 to 6 carbon atoms or an aromatic substituent having 6 carbon atoms, particularly preferably an alkyl substituent having 1 to 4 carbon atoms, and especially preferably an alkyl substituent having 1 or 2 carbon atoms.
[0119] Alkoxyalkylsilanes are not preferred. Both the alkoxy substituent and the alkyl group include straight-chain or branched chains. Straight-chain alkyl substituents with 1 to 6 carbon atoms are preferred, alkyl substituents with 1 to 4 carbon atoms are particularly preferred, and alkyl substituents with 1 or 2 carbon atoms are especially preferred.
[0120] Typical examples of orthosilicates are tetraalkoxysilanes, preferably tetramethoxysilanes and tetraethoxysilanes, and alkoxyalkylsilanes, preferably triethoxymethylsilane, diethoxydiethylsilane, ethoxytrimethylsilane, trimethoxymethylsilane, dimethoxydimethylsilane, and methoxytrimethylsilane. Tetraalkoxysilanes are preferred, especially tetramethoxysilanes and tetraethoxysilanes, with tetraethoxysilane being particularly preferred.
[0121] Preferably, component (C1) is at least one compound selected from the group consisting of silicates, borates, nitrates or phosphates, and particularly preferably at least one compound selected from the group consisting of silicates, nitrates or phosphates.
[0122] (C2a) Aromatic monocarboxylic acids
[0123] The optional aromatic monocarboxylic acid is preferably benzoic acid, which can be used in the form of a free acid or, particularly preferably, in the form of its alkali metal salt, especially, particularly preferably in the form of sodium benzoate.
[0124] In a preferred embodiment of the present invention, aromatic monocarboxylic acids are not present.
[0125] (C2b) Aliphatic monocarboxylic acids
[0126] Aliphatic monocarboxylic acids are organic aliphatic alkane or olefinic carboxylic acids. They are often used as corrosion inhibitors for ferrous materials in coolants (provided they are sufficiently water-soluble). Preferably, such aliphatic monocarboxylic acids have 5 to 12 carbon atoms, particularly preferably 6 to 10 carbon atoms, and especially preferably 8, 9, or 10 carbon atoms.
[0127] Typical monocarboxylic acids of this kind are valeric acid, 2,2-dimethylpropionic acid, hexanoic acid, 2,2-dimethylbutyric acid, octanoic acid, 2-ethylhexanoic acid, nonanoic acid, isononanoic acid, decanoic acid, undecanoic acid, and dodecanoic acid, as well as mixtures of their isomers, especially mixtures of 2-ethylhexanoic acid and isononanoic acid isomers.
[0128] However, this manifests as one possible implementation in which the aliphatic monocarboxylic acid is used in place of an alkali metal salt of the aliphatic monocarboxylic acid, preferably in the form of a lithium, sodium, or potassium salt, and particularly preferably in the form of a sodium or potassium salt, instead of the free acid.
[0129] (C3) Organic dicarboxylic acids having 4 to 20 carbon atoms
[0130] The organic dicarboxylic acid having 4 to 20 carbon atoms is a straight-chain or branched alkanedicarboxylic acid, preferably a straight-chain alkanedicarboxylic acid or alkenedicarboxylic acid, particularly preferably an alkanedicarboxylic acid, especially preferably having 5 to 14 carbon atoms, and even more particularly preferably having 6 to 12 carbon atoms.
[0131] Preferably, the dicarboxylic acid (C3) is selected from the group consisting of succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, heptanoic acid, nonanoic acid, sebacic acid, undecanoic acid, dodecanoic acid, and alkyl and alkenyl succinic acids and glutaric acids such as 2-methylsuccinic acid, 2-ethyl-3-methylsuccinic acid, 2-ethylglutaric acid, 2-dodecylsuccinic acid, 2-dodecenylsuccinic acid, 2-phenylsuccinic acid, 2-(p-methylphenyl)succinic acid, 2,2-dimethylsuccinic acid, 2,3,4-trimethylglutaric acid, 2,2,3-trimethylglutaric acid, pentenoic acid (2-pentenoic acid), itaconic acid, 2-hexenic acid, 3-hexenic acid, 5-methyl-2-hexenic acid, and 2,3-dimethyl-2-pentenoic acid.
[0132] Among them, dicarboxylic acids having 6 to 12 carbon atoms are preferred, particularly preferably alkyl dicarboxylic acids having 6 to 12 carbon atoms, and especially preferably straight-chain alkyl dicarboxylic acids having 6 to 12 carbon atoms.
[0133] In particular, adipic acid, sebacic acid, azelaic acid, and dodecanoic acid are preferred as dicarboxylic acids (D3).
[0134] (C4) Azole compounds
[0135] Within the framework of this literature, azole derivatives (C4) are five-membered heterocyclic compounds having two or three heteroatoms selected from the group consisting of nitrogen and sulfur. These compounds may contain no sulfur atom or at most one inserted sulfur atom in the ring structure, and optionally have an aromatic or saturated six-membered fused ring.
[0136] These five-membered heterocyclic compounds (azole derivatives) typically contain two nitrogen atoms and no sulfur atoms; three nitrogen atoms and no sulfur atoms; or one nitrogen atom and one sulfur atom as heteroatoms.
[0137] The preferred groups of the above-mentioned azole derivatives are fused imidazoles and fused 1,2,3-triazole compounds of the following general formula:
[0138] (III)
[0139] Or (IV)
[0140] Where the variable R is hydrogen or C1 to C2. 10 Alkyl groups, especially methyl or ethyl groups, and
[0141] Variable X refers to a nitrogen atom or a CH group.
[0142] Typical and preferred examples of azole derivatives of general formula (III) are benzimidazole (X=CH, R=H), benzotriazole (X=N, R=H), and tolyltriazol (X=N, R=CH3). Typical examples of azole derivatives of general formula (IV) are hydrogenated 1,2,3-methylbenzotriazol (X=N, R=CH3).
[0143] Another preferred group of the azole derivatives mentioned is benzothiazole compounds of general formula (V).
[0144]
[0145] in
[0146] The variable R has the above meaning, and
[0147] Variable R' refers to hydrogen, C1 to C 10 Alkyl (especially methyl or ethyl), or especially mercapto (-SH). It is conceivable that, although less preferred, R' could also be of the general formula -(C m H 2m )-COOR'' carboxyl group, where m is an integer from 1 to 4, and R'' represents hydrogen, C1-C 10 Alkyl (especially methyl or ethyl), or C6-C 12Aryl groups. Examples of this are (2-benzothiazolylthio)acetic acid, (2-benzothiazolylthio)acetic acid ester, 3-(2-benzothiazolylthio)propionic acid, or 3-(2-benzothiazolylthio)propionic acid ester. If these compounds are used as acids, they are not included in the category of carboxylic acids excluded by this invention. A typical example of an azole derivative of general formula (V) is 2-mercaptobenzothiazole.
[0148] In addition, non-fused azole derivatives of general formula (VI) are
[0149] (VI)
[0150] The variables X and Y together represent two nitrogen atoms or one nitrogen atom and one CH group, such as 1H-1,2,4-triazole (X=Y=N) or preferably imidazole (X=N, Y=CH).
[0151] For the purposes of this invention, benzimidazole, benzotriazole, methylbenzotriazole, hydrogenated methylbenzotriazole or mixtures thereof are particularly preferred as azole derivatives, especially benzotriazole or methylbenzotriazole, particularly methylbenzotriazole.
[0152] The aforementioned azole derivatives are commercially available or can be prepared by conventional methods. Hydrogenated benzotriazoles (such as hydrogenated methylbenzotriazole) can also be prepared according to DE-A 1 948 794 and are also commercially available.
[0153] Preferably, the azole is selected from the group consisting of benzotriazole, methylbenzotriazole, (2-benzothiazolylthio)acetic acid, 3-(2-benzothiazolylthio)propionic acid and 2-mercaptobenzothiazol.
[0154] (C5) Organic amines
[0155] The amine (C5) preferably has 2 to 9, particularly 4 to 8, carbon atoms. The amine (C5) is preferably a tertiary amine. The amine (C5) preferably contains 0 to 3 ether oxygen atoms or 0 to 3, preferably 0 to 2 hydroxyl groups. Typical examples of amines (C5) are ethylamine, propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, 2-ethylhexylamine, n-nonylamine, isononylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, mono-, di- and triethanolamines, mono-, di- and tri-isopropanolamines, C4-C 10 Alkyl diethanolamine, C1-C 10 Alkyl diisopropanolamines, piperidine, morpholine, cyclohexylamine, aniline, and benzylamine. Aliphatic and alicyclic amines (C5) are typically saturated.
[0156] The amine (C5) is preferably selected from diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, and C4-C. 10Alkyl diethanolamine, C1-C 10 The group consisting of alkyl diisopropanolamines is particularly preferred, especially the group consisting of triethanolamine, diisopropanolamine, C4-C8 alkyl diethanolamine, and C1-C4 alkyl diisopropanolamines, and very particularly preferred, the group consisting of triethanolamine, diisopropanolamine, N-methyl diisopropanolamine, n-butyl diethanolamine, and n-octyl diethanolamine.
[0157] In a preferred embodiment, in addition to polyethyleneimine, the coolant according to the invention also contains at least one organic amine, particularly preferably in an amount of 0.01% to 3% by weight, preferably at least 0.02% to 2% by weight, and particularly preferably at least 0.05% to 1% by weight.
[0158] (D) Inorganic base
[0159] The pH value of antifreeze at the end user is typically in the range of 4 to 11.5, preferably 5 to 10, and especially 6 to 9.
[0160] To set this pH value, at least one inorganic base (D) is added at any stage in the method for preparing the coolant from the concentrated precursor. Here, the at least one inorganic base may be included in the composition of the present invention, in the super-concentrate, or in the concentrate, or added when preparing the super-concentrate by mixing the composition of the present invention with component (A) and / or (B), or when preparing the concentrate by mixing the super-concentrate with component (A) and / or (B), or when preparing the coolant by mixing the concentrate with component (A) and / or (B).
[0161] Therefore, the compositions of the present invention optionally contain a certain amount of an inorganic base, which, upon corresponding dilution, can set the desired pH value in the coolant. The compositions according to the invention preferably contain an alkali metal hydroxide, particularly preferably a solid lithium, sodium, or potassium hydroxide, and where appropriate, an aqueous solution of lithium hydroxide, sodium hydroxide, or potassium hydroxide.
[0162] Less preferred are lithium, sodium, or potassium carbonates or bicarbonates.
[0163] Sodium and potassium are preferred alkali metals.
[0164] (E) Optional other ingredients, selected from the group consisting of hard water stabilizers, defoamers, colorants and bittering agents. .
[0165] As a further commonly used auxiliary means, the compositions of the present invention may also contain a small amount of defoamer (typically 0.003% to 0.008% by weight in the finished product diluent), and, in the event of accidental ingestion, for hygiene and safety reasons, a bitter substance (e.g., denatium benzoate) and a dye. In a preferred embodiment of the invention, at least one bittering agent is contained, preferably at least one bittering agent and a coloring agent, particularly preferably at least one bittering agent, a coloring agent and a defoamer.
[0166] In addition, the composition may contain one or more hard water stabilizers based on copolymers of polyacrylic acid, polymaleic acid, acrylic acid-maleic acid copolymers, polyvinylpyrrolidone, polyvinylimidazole, vinylpyrrolidone-vinylimidazole copolymers, and / or copolymers of unsaturated carboxylic acids and olefins. The proportions in the composition are chosen such that, upon corresponding dilution, the amount in the finished diluted coolant is at most 1% by weight.
[0167] Concentrates, Super Concentrates
[0168] To reduce transport volume, high-water-content coolants are typically not shipped; instead, concentrates are sold where the water content has been removed or significantly reduced. End users then prepare the coolant from the concentrate by adding water.
[0169] To further reduce transportation volume, so-called super-concentrates are often prepared in batches, in which not only is moisture removed or significantly reduced, but also glycol compounds are removed or significantly reduced. From these super-concentrates, formulators then produce concentrates at the regional level by mixing glycol compounds.
[0170] Therefore, the present invention also relates to coolant concentrates, comprising
[0171] - No more than 15% by weight, preferably no more than 10% by weight, and especially preferably no more than 5% by weight of water (A).
[0172] - At least 50% by weight, preferably at least 60% by weight, particularly preferably at least 70% by weight of at least one alkylene glycol, alkylene glycol monoalkyl ether or glycerol (B).
[0173] As an inhibitor (C)
[0174] - (C1) Optionally selected from at least one inorganic compound consisting of silicates, borates, nitrates, molybdates and phosphates.
[0175] -(C2a) benzoic acid, optionally an aromatic monocarboxylic acid
[0176] -(C2b) optionally at least one aliphatic monocarboxylic acid,
[0177] - (C3) Optionally at least one organic dicarboxylic acid having 4 to 20 carbon atoms
[0178] - (C4) At least one azole compound, preferably at least one triazole compound
[0179] - (C5) optionally at least one organic amine,
[0180] - (D) Optionally at least one inorganic base
[0181] - (E) Optionally, at least one other ingredient selected from the group consisting of hard water stabilizers, defoamers, colorants, and bittering agents, and
[0182] -0.02% to 10% by weight, preferably 0.1% to 8% by weight, particularly preferably 0.2% to 6% by weight of at least one polyethyleneimine (F).
[0183] If an inorganic compound (C1) is present in the concentrate, it is present in an amount of 0.2% to 10% by weight, preferably 0.4% to 8% by weight, and particularly preferably 0.5% to 6% by weight in each case.
[0184] If acids (C2a), (C2b) and / or (C3) are present in the concentrate, they are present in amounts of 0.2% to 10% by weight, preferably 0.4% to 8% by weight, and particularly preferably 0.5% to 6% by weight in each case.
[0185] If an organic amine (C5) is present in the concentrate, the amount is from 0.02% to 6% by weight, preferably from at least 0.04% to 4% by weight, and particularly preferably from at least 0.1% to 2% by weight.
[0186] If the inorganic base (D) is present in the concentrate, it is present in an amount of 0.2% to 10% by weight, preferably 0.4% to 8% by weight, and particularly preferably 0.5% to 6% by weight in each case.
[0187] Another subject of the present invention is a coolant superconcentrate, comprising:
[0188] - No more than 15% by weight, preferably no more than 10% by weight, and especially preferably no more than 5% by weight of water (A).
[0189] - At least 50% by weight, preferably at least 60% by weight, particularly preferably at least 70% by weight of at least one alkylene glycol, alkylene glycol monoalkyl ether or glycerol (B).
[0190] As an inhibitor (C)
[0191] - (C1) Optionally selected from at least one inorganic compound consisting of silicates, borates, nitrates, molybdates and phosphates.
[0192] -(C2a) benzoic acid, optionally an aromatic monocarboxylic acid
[0193] -(C2b) optionally at least one aliphatic monocarboxylic acid,
[0194] - (C3) Optionally at least one organic dicarboxylic acid having 4 to 20 carbon atoms
[0195] - (C4) At least one azole, preferably at least one triazole compound
[0196] - (C5) optionally at least one organic amine,
[0197] - (D) Optionally at least one inorganic base
[0198] - (E) Optionally, at least one other ingredient selected from the group consisting of hard water stabilizers, defoamers, colorants, and bittering agents, and
[0199] -0.03% to 30% by weight, preferably 0.15% to 24% by weight, particularly preferably 0.3% to 18% by weight of at least one polyethyleneimine (F).
[0200] If an inorganic compound (C1) is present in the superconcentrate, it is present in an amount of 0.4% to 20% by weight, preferably 0.8% to 16% by weight, and particularly preferably 1.5% to 18% by weight in each case.
[0201] If acids (C2a), (C2b) and / or (C3) are present in the superconcentrate, they are present in amounts of 0.4% to 20% by weight, preferably 0.8% to 16% by weight, and particularly preferably 1.5% to 18% by weight in each case.
[0202] If an organic amine (C5) is present in the superconcentrate, its amount is from 0.03% to 9% by weight, preferably from at least 0.06% to 6% by weight, and particularly preferably from at least 0.15% to 3% by weight.
[0203] If the inorganic base (D) is present in the superconcentrate, it is present in an amount of 0.4% to 20% by weight, preferably 0.8% to 16% by weight, and particularly preferably 1.5% to 18% by weight in each case.
[0204] The present invention also provides a method for preparing the above-mentioned coolant concentrate from the above-mentioned coolant ultra-concentrate, wherein at least one alkylene glycol, alkylene glycol monoalkyl ether or glycerol (B) is added to the coolant ultra-concentrate in appropriate amounts. Example
[0205] Example 1 (Comparison) 2 3 4 Monoethylene glycol (wt%) 98.72 98.62 98.52 98.32 Toluenetriazole (wt%) 0.2 0.2 0.2 0.2 Tetraethoxysilane (wt%) 0.2 0.2 0.2 0.2 Triethanolamine (wt%) 0.72 0.72 0.72 0.72 Isonononanoic acid (wt%) 0.16 0.16 0.16 0.16 Polyethyleneimine (*) (by weight %) 0.1 0.2 0.4 Electrical conductivity, 50% in water (µS / cm) 100.0 69.5 108.6 112.2 pH value, 50% in water 7.7 8.1 8.2 8.4 <![CDATA[Corrosion rate, G-AlSi6Cu4 (mg / cm 2 ).]]> -5.61 -1.68 -0.70 -0.40
[0206] (*) Polyethyleneimine has a molecular weight (Mw) of 5000 g / mol (determined by GPC), a pH of 11, and a primary:secondary:tertiary amine ratio (as determined by GPC). 13 A 50% aqueous solution of polyethyleneimine with a C-NMR concentration of 1:1:0.7.
[0207] Example 1 represents a base formulation without polyethyleneamine. Examples 2-4 describe the addition of different concentrations of polyethyleneamine. Clearly, according to ASTM D1384, the addition of polyethyleneamine significantly reduces the corrosion rate on aluminum. Meanwhile, the effect on electrical conductivity is minimal.
Claims
1. A coolant comprising - At least 40% by weight water (A) - At least 30% by weight of alkylene glycols, alkylene glycol monoalkyl ethers and glycerol (B). -0.1% to 5% by weight of at least one acid selected from the group consisting of: --(C2a)benzoic acid is an aromatic monocarboxylic acid. -- (C2b) at least one aliphatic monocarboxylic acid, and -- (C3) At least one organic dicarboxylic acid having 4 to 20 carbon atoms, - At least 0.01% to 5% by weight of at least one polyethyleneimine (F).
2. The coolant according to claim 1, characterized in that, The polyethyleneimine (F) is selected from the group consisting of formula (I). Japanese style (II) in, x and y independently represent 0 (zero) or a positive integer, provided that - In equation (II), the sum of x and y is not 0 (zero).
3. The coolant according to claim 2, characterized in that, x is independently of each other at least 1, particularly preferably at least 2, very particularly preferably at least 3, especially at least 5, and especially at least 10. y is at least 1, particularly preferably at least 2, very particularly preferably at least 3, especially at least 5, and especially at least 10. x and y can be independent of each other and can be up to 1500, preferably up to 1400, particularly preferably up to 1300, very particularly preferably up to 1200, especially up to 1000, and especially up to 750.
4. The coolant according to claim 1, characterized in that, pass 13 The ratio of primary nitrogen atoms to secondary nitrogen atoms to tertiary nitrogen atoms in polyethyleneimine, as determined by C-NMR spectroscopy, is preferably 1:0.5 to 1.5:0.3 to 0.9, more preferably 1:0.6 to 1.3:0.4 to 0.8, more preferably 1:0.7 to 1.3:0.4 to 0.8, and particularly 1:0.9 to 1.1:0.5 to 0.
8.
5. The coolant according to any one of the preceding claims, characterized in that, The weight-average molecular weight (Mw as measured by GPC) of the polyethyleneimine (F) is at least 500 g / mol, preferably at least 750 g / mol, very particularly preferably at least 1000 g / mol, and less than 55,000 g / mol, preferably less than 40,000 g / mol, even more preferably less than 30,000 g / mol, and even more preferably less than 15,000 g / mol.
6. The coolant according to any one of the preceding claims further comprises at least one of the following components. As an inhibitor (C) - (C1) Optionally selected from at least one inorganic compound consisting of silicates, borates, nitrates, molybdates and phosphates. -(C2a) benzoic acid, optionally an aromatic monocarboxylic acid -(C2b) optionally at least one aliphatic monocarboxylic acid, - (C3) Optionally at least one organic dicarboxylic acid having 4 to 20 carbon atoms - (C4) At least one azole compound, preferably at least one triazole compound - (C5) optionally at least one organic amine, - (D) Optionally at least one inorganic base - (E) Optionally, at least one other ingredient is selected from the group consisting of hard water stabilizers, defoamers, colorants and bittering agents.
7. The coolant according to any one of the preceding claims, characterized in that, The presence of at least one aliphatic monocarboxylic acid (C2b) is preferred, selected from valeric acid, 2,2-dimethylpropionic acid, hexanoic acid, 2,2-dimethylbutyric acid, octanoic acid, 2-ethylhexanoic acid, nonanoic acid, isononanoic acid, decanoic acid, undecanoic acid and dodecanoic acid and mixtures of their isomers, particularly preferred is a mixture of 2-ethylhexanoic acid or isononanoic acid isomers, and very particularly preferred is a mixture of isononanoic acid isomers.
8. The coolant according to any one of the preceding claims, characterized in that, There are no inorganic compounds (C1) selected from the group consisting of silicates, borates, nitrates, molybdates and phosphates.
9. The coolant according to any one of the preceding claims, characterized in that, The presence of at least one organic amine (C5), preferably selected from diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, C4-C 10 Alkyl diethanolamine and C1-C 10 The group consisting of alkyl diisopropanolamines.
10. The coolant according to any one of the preceding claims, characterized in that, The molar ratio of the tertiary amino group in the polyethyleneimine (F) and optionally the organic amine (C5) (total) to the acids (C2a), (C2b) and (C3) (total) is preferably from 1:0.01 to 1:0.
5.
11. Use of polyethyleneimine (F) as claimed in any one of claims 1 to 6 in a coolant, said coolant being used for a cooling system of a stationary motor or a vehicle having an internal combustion engine, an electric motor, a fuel cell or a hybrid engine having a combination of an internal combustion engine and an electric motor or a combination of an internal combustion engine and a fuel cell, or for a generator, such as a wind turbine.
12. The use according to claim 11, characterized in that, The polymer (F) is used as a corrosion inhibitor.
13. The use according to claim 12, characterized in that, The polymer (F) is used as a corrosion inhibitor for iron- and / or aluminum-containing materials.
14. A coolant concentrate containing - No more than 15% by weight, preferably no more than 10% by weight, and especially preferably no more than 5% by weight of water (A). - At least 50% by weight, preferably at least 60% by weight, particularly preferably at least 70% by weight of at least one alkylene glycol, alkylene glycol monoalkyl ether, or glycerol (B). As an inhibitor (C) - (C1) Optionally selected from at least one inorganic compound consisting of silicates, borates, nitrates, molybdates and phosphates. -(C2a) benzoic acid, optionally an aromatic monocarboxylic acid -(C2b) optionally at least one aliphatic monocarboxylic acid, - (C3) Optionally at least one organic dicarboxylic acid having 4 to 20 carbon atoms - (C4) At least one azole compound, preferably at least one triazole compound - (C5) Optionally at least one organic amine - (D) Optionally at least one inorganic base - (E) Optionally, at least one other ingredient selected from the group consisting of hard water stabilizers, defoamers, colorants, and bittering agents, and -0.1% to 10% by weight, preferably 0.2% to 8% by weight, particularly preferably 0.5% to 6% by weight of at least one polyethyleneimine (F).
15. A coolant superconcentrate, containing - No more than 15% by weight, preferably no more than 10% by weight, and especially preferably no more than 5% by weight of water (A). - At least 50% by weight, preferably at least 60% by weight, particularly preferably at least 70% by weight of at least one alkylene glycol, alkylene glycol monoalkyl ether or glycerol (B) as an inhibitor (C). - (C1) Optionally selected from at least one inorganic compound consisting of silicates, borates, nitrates, molybdates and phosphates. -(C2a) benzoic acid, optionally an aromatic monocarboxylic acid -(C2b) optionally at least one aliphatic monocarboxylic acid, - (C3) Optionally at least one organic dicarboxylic acid having 4 to 20 carbon atoms - (C4) At least one azole, preferably at least one triazole compound - (C5) optionally at least one organic amine, - (D) Optionally at least one inorganic base - (E) Optionally, at least one other ingredient selected from the group consisting of hard water stabilizers, defoamers, colorants, and bittering agents, and -0.3% to 30% by weight, preferably 0.6% to 24% by weight, particularly preferably 1.5% to 18% by weight of at least one polyethyleneimine (F).
16. A method for preparing the coolant concentrate according to claim 14 from the coolant ultraconcentrate of claim 15, characterized in that, Add an appropriate amount of at least one of alkylene glycol, alkylene glycol monoalkyl ether, or glycerol (B) to the coolant superconcentrate.