Water-based hydraulic fluid

Abstract

This invention relates to water-based hydraulic fluids comprising a) a phosphonocarboxylic acid of formula (1) or a salt thereof, wherein R 1 The symbol represents hydrogen or a C1-C4 alkyl group, X represents hydrogen, an alkali metal, an alkaline earth metal, or an ammonium group, n represents a number from 5 to 7, and the sum (N+n+3) is from 8 to 14, where N is R 1 The total number of carbon atoms in the fluid, b) at least one water-soluble amine, c) at least one polyol, and d) water, and the hydraulic fluid has a pH of 7 to 12. (1).

Description

Technical Field

[0001] This invention relates to water-based hydraulic fluids and additive packages for such hydraulic fluids, the additive packages comprising phosphonocarboxylic acids and having improved application technology characteristics. Background Technology

[0002] Water-based hydraulic fluids are used in many applications, particularly when mineral oil-containing hydraulic fluids exiting hydraulic systems pose a fire or environmental hazard. Typical applications include steel mills, forging plants, coal mining and oil and gas transportation systems, and wind farms. The use of such hydraulic fluids must be associated with a low coefficient of friction and sufficient "wear resistance" to prevent damage to metal components used under high loads.

[0003] Additionally, due to the reduced lubrication compared to mineral oil-based fluids, carefully selected additive packages must be used. A water-based hydraulic fluid typically comprises the following components:

[0004] (1) Water 35-70%

[0005] (2) Freezing point depressant (e.g., glycol) 25-50%

[0006] (3) Viscosity modifier 0-20%

[0007] (3) Lubricant 0-20%

[0008] (4) Corrosion inhibitor 0-10%

[0009] (5) pH adjusters (e.g., alkanolamines) 0 - 10%

[0010] (6) Defoamer 0-2%

[0011] (7) Antioxidant 0-2%

[0012] (8) Dye 0 - 0.1%

[0013] The pH value is typically alkaline, generally > 9. An increased pH value helps prevent corrosion. Based on the above composition, the lubricant plays a crucial role.

[0014] DE-A-2534808 describes an oxygen-alkylated polyamide with improved lubrication properties, formed from dicarboxylic acids and low-molecular-weight polyamines, and its use in water-based hydraulic fluids.

[0015] US-4138346 discloses phosphate monoesters and diesters, as well as sulfur compounds such as mercaptobenzothiazole, dithiobisthiazole, and alkyl sulfides as lubricants in aqueous hydraulic fluids.

[0016] US-2016 / 0208193 discloses compositions in aqueous hydraulic fluids formed from water-soluble phosphate esters and sulfide compounds.

[0017] EP2470627 discloses alkoxylated alkyl phosphates as lubricating additives.

[0018] US8563484 discloses an aqueous hydraulic fluid that forces the use of a first lubricant formed of a phospholipid type and a second lubricant formed of a group of substances composed of alkoxylate salts.

[0019] DE102016208486 teaches aqueous compositions containing

[0020] a) A substance consisting of one or more glycoamines selected from formula (1).

[0021]

[0022] in

[0023] R 1 Represents CH3 or 2-hydroxyethyl, and

[0024] (b) One or more substances selected from the group consisting of mono, di, or tricarboxylic acids and their salts having 8-22 carbon atoms.

[0025] In addition to the aforementioned requirements for good lubrication performance, other requirements have been added to the water-based hydraulic fluids currently in use.

[0026] Because salt is added during the use of the liquid, or because hard water or seawater is required for its preparation for economic reasons, additives must be compatible with hard water and electrolytes. Many known additives do not meet one or more of these conditions. Consequently, many carboxylic acids, and especially phosphate esters, are unstable with respect to water hardness. Furthermore, defoamers are often omitted for economic and ecological reasons, thus limiting the selection to non-foaming additives. Ethoxylates and other alkoxylates, aliphatic carboxylic acids (especially fatty acids), and aliphatic carboxylic acid alkanolamides are known to have strong foaming effects due to their surfactant structures. Many companies have committed to minimizing the fossil carbon content in their products; therefore, additives with lower fossil carbon content are preferred.

[0027] Furthermore, additives must possess favorable ecotoxicological properties, particularly when the hydraulic fluids are used in ecologically sensitive areas such as the North Sea or the Arctic Ocean. Therefore, for use in oil transport in the North Sea, every additive in the hydraulic fluid must meet the OSPAR criteria, which require good biodegradability and low toxicity. Many additives do not meet these criteria. Thus, imidazolines and mercaptobenzothiazoles are not permitted due to their toxicity relative to marine organisms, leading to the frequent use of additives with poor application technical properties. Similarly, for both eco-friendly and economic reasons, the lowest possible concentration of additives is desirable. This is often difficult because additives achieving specific effects (e.g., lubrication) often negatively impact other properties, such as reducing corrosion protection.

[0028] Therefore, the main area for improvement is to find components that do not negatively affect the effectiveness of other additives. Summary of the Invention

[0029] Therefore, the object of this invention is to find an improved lubricant additive for water-based hydraulic fluids that is stable in hard water and has good ecotoxicological properties, wherein the lubricant additive requires only a low concentration for use.

[0030] Phosphonocarboxylic acids have been found to possess excellent and adequate lubricating properties for applications in hydraulic fluids. Furthermore, they are non-foaming, stable against hard water and electrolytes, and exhibit very good biodegradability. Therefore, hydraulic fluids can be prepared for known applications, but particularly for marine applications in ecologically sensitive areas such as the North Sea, taking into account both ecological and economic considerations of systems known to date and permitted there.

[0031] Therefore, the subject of this invention is a water-based hydraulic fluid, which comprises

[0032] a) Phosphonocarboxylic acids of Formula 1 or their salts,

[0033]

[0034] in

[0035] R 1 Indicates hydrogen or C1-C4 alkyl.

[0036] X represents hydrogen, alkali metal, alkaline earth metal, or ammonium group.

[0037] n represents a number from 5 to 7, and

[0038] The sum (N+n+3) ranges from 8 to 14, where N is the total number of carbon atoms in R.

[0039] b) At least one water-soluble amine

[0040] c) at least one polyol, and

[0041] d) Water, and

[0042] The hydraulic fluid has a pH of 7 to 12.

[0043] pH values ​​were determined for 10% by weight of a hydraulic fluid solution in water with a water hardness of 20° dH.

[0044] Another subject of the present invention is the use of the compound of Formula 1 as a lubrication enhancer in water-based hydraulic fluids.

[0045] Another subject of the present invention is a method for improving the lubrication properties of a water-based hydraulic fluid, wherein a compound of formula 1 is added to the hydraulic fluid.

[0046] All percentage data in this application are weight percentages based on the total weight of the hydraulic fluid as 100% by weight. Exceptions are indicated otherwise.

[0047] The hydraulic fluid according to the invention preferably contains 35-70% by weight of water.

[0048] The component a) of the hydraulic fluid is a compound of formula 1.

[0049] R 1 Preferably, it represents hydrogen, methyl, or ethyl; particularly preferably, it represents hydrogen or ethyl; and very particularly preferably, it represents hydrogen.

[0050] In the case of a free acid, X is hydrogen; in the case of a salt, it is an alkali metal ion, an alkaline earth metal ion, or an ammonium ion. In the case of an ammonium ion, it is preferably a compound generated by protonation from an amine described below as a neutralizing agent. X preferably represents an ammonium ion generated by protonation from an alkanolamine. Suitable alkanolamines are described below.

[0051] n is preferred for numbers between 4 and 7, especially preferred for numbers between 5 and 7, and very especially preferred for n equal to 7.

[0052] The sum (N+n+3) is given by R 1 The total number of all carbon atoms (denoted as N) and n are derived. The sum (N+n+3) is preferably 8-12, particularly preferably 9-11, and very particularly preferably n equals 10.

[0053] The hydraulic fluid according to the invention generally contains 0.1-30% by weight of a compound according to Formula 1. It preferably contains 0.2-15% by weight, or particularly preferably 0.3-10% by weight, of a phosphonocarboxylic acid of Formula 1. The same amounts apply to the uses and methods according to the invention.

[0054] In a preferred embodiment, the water-based hydraulic fluid according to the invention comprises a corrosion inhibitor. Suitable corrosion inhibitors are alkali metal salts, alkaline earth metal salts, and amine salts of compounds of formulas 2-4, such as benzenesulfonylaminohexanoic acid, toluenesulfonylaminohexanoic acid, (N-methyl)benzenesulfonylaminohexanoic acid, alkylaminocarboxylic acids, particularly isonononylaminohexanoic acid, and triazine-2,4,6-tris(aminohexanoic acid) or compounds of formulas 2-4.

[0055] a) Toluenesulfonylaminohexanoic acid or benzenesulfonylaminohexanoic acid (Formula 2)

[0056]

[0057] Where R 2 R 3 = H or CH3

[0058] b) Isonononanoylaminohexanoic acid (Formula 3)

[0059]

[0060] c) Triazine-triaminohexanoic acid (Formula 4)

[0061]

[0062] Other known and suitable corrosion inhibitors are linear or branched C6 to C6 corrosion inhibitors. 10 Carboxylic acids, such as octanoic acid, 2-ethylhexanoic acid, nonanoic acid, decanoic acid, and isodecanic acid, C4 to C4. 24 Dicarboxylic acids, such as succinic acid, adipic acid, maleic acid, citric acid, and longer-chain dicarboxylic acids, such as sebacic acid, undecanoic acid, or dodecanoic acid, wherein the chain can be branched or cyclic, such as 6-carboxy-4-hexyl-2-cyclohexene-octanoic acid. Salts of the compounds mentioned above can also be used.

[0063] If a salt of one of the aforementioned corrosion inhibitors is used, it is preferably a salt produced by the reaction of free acid with a neutralizing agent contained in the hydraulic fluid.

[0064] If a corrosion inhibitor is used, the amount of corrosion inhibitor is generally 0.1-20% by weight, preferably 0.5-15% by weight, or particularly preferably 0.75-10% by weight.

[0065] If a salt of corrosion inhibitor is used, the concentration of the corrosion inhibitor used, given as a weight percentage, is correspondingly higher due to the higher molecular weight of the salt relative to the free acid.

[0066] The hydraulic fluid according to the invention may contain additional lubricants for reducing friction and wear. Suitable lubricants herein are amine salts, alkali metal salts, or alkaline earth metal salts of alkyl phosphates or aryl phosphates, and / or amine salts, alkali metal salts, or alkaline earth metal salts of phosphate esters of alkoxylated alcohols. Polyalkylene glycols may also be used. Polyalkylene glycols can be obtained by anionic polymerization of epoxides of formula 5 with mono-, di-, tri-, tetra-, and polyfunctional alcohols or amines or mixtures thereof, or by metal-catalyzed polymerization.

[0067]

[0068] Where R 4 = Hydrogen, methyl, ethyl.

[0069] If multiple alkylene oxides are used, polymerization can be carried out sequentially (monomers arranged stepwise) or with a mixture of alkylene oxides (monomers arranged randomly). Suitable starting alcohols for these polyalkylene glycols include, for example, ethylene glycol, propylene glycol, trimethylolpropane, glycerol, pentaerythritol, sorbitol, and other polyols. Suitable amines are, for example, compounds referred to below as neutralizers, provided they contain an acidic NH bond.

[0070] Other suitable lubricants are sulfur compounds, such as mercaptobenzothiazole, dithiobis(thiazole) and alkyl disulfides, thiophosphonates (salts), or inorganic compounds such as phosphoric acid or metal sulfides. The arylsulfonamide carboxylic acid shown in formula (6) exhibits the same effect as a lubricant in addition to its properties as a corrosion inhibitor.

[0071] In a preferred embodiment of the invention, the hydraulic fluid does not contain additional lubricant because the lubricating effect of phosphonocarboxylic acid is sufficient.

[0072] Other lubricants, especially polyalkylene glycols obtained in this way, preferably have a kinematic viscosity at 50°C of greater than 20 mm. 2 / s change to below 3000 mm 2 / s, typically including 25-2000 mm 2 kinematic viscosity value per s (measured according to ASTM D7042).

[0073] The hydraulic fluid according to the present invention contains a water-soluble amine as component b).

[0074] This amine is used as a neutralizing agent to adjust the pH of the hydraulic fluid to a value of 7-12, preferably 8-11, and particularly preferably 9-10. An amine is considered water-soluble when it is soluble in completely desalinated water at 20°C at at least 1% by weight, preferably at least 5% by weight.

[0075] The water-soluble amines of Formula 6 are suitable for use as neutralizing agents.

[0076] NR 5 R 6 R 7 (6)

[0077] in

[0078] R 5 R 6 and R 7 Choose independently the following groups.

[0079] hydrogen;

[0080] A hydrocarbon group having 1 to 20 carbon atoms, wherein the hydrocarbon group may have substituents, the substituents may include heteroatoms;

[0081] C6-C 12 The group may be aryl or heteroaryl having 5 to 12 ring members, and may contain substituents;

[0082] Groups of Formula 7

[0083] -(R 8 -O) p -R 9 (7)

[0084] in

[0085] R 8 Indicates an alkylene group having 2 to 6 carbon atoms.

[0086] R 9 It represents hydrogen, a hydrocarbon group having 1 to 24 carbon atoms, or the formula -NR. 10 R 11 group,

[0087] p represents a number between 2 and 50, and

[0088] R 10 R 11 The groups, which independently represent hydrogen, are aliphatic groups having 1 to 24 carbon atoms, aryl or heteroaryl groups having 5 to 12 ring members, and poly(alkylene oxide) groups having 1 to 50 poly(alkylene oxide) units, wherein the polyalkylene oxide units are derived from alkylene oxide units having 2 to 6 carbon atoms.

[0089] Or R 10 and R 11 Together with the nitrogen atoms they are bonded to, they form rings with 4, 5, 6 or more ring members;

[0090] Groups of Formula 8

[0091] -[R12 -N(R 13 )] q -H (8)

[0092] in

[0093] R 12 Indicates an alkylene group having 2 to 6 carbon atoms.

[0094] Each R 13 Independently representing hydrogen, alkyl or hydroxyalkyl groups having up to 24 carbon atoms, polyoxyalkylene-(R 8 -O) r -R 9 Or polyimide alkylene-[R] 12 -N(R 14 )2] s , where R 8 R 9 and R 12 With the meanings given above, R 14 Indicates hydrogen, alkyl or hydroxyalkyl with up to 24 carbon atoms, polyoxyalkylene-(R 8 -O) r -R 9 And r and s independently represent 1 to 50, and

[0095] q represents a number from 1 to 20;

[0096] Or R 5 and R 6 They form rings together with the nitrogen atoms to which they are bonded;

[0097] The prerequisite is that the group R 5 R 6 and R 7 Not all of them represent hydrogen.

[0098] In the first preferred embodiment, R 5 and / or R 6 and / or R 7 Each can independently represent either hydrogen or aliphatic groups, however R 5 R 6 and R 7 At least one of them represents an aliphatic group. The aliphatic group preferably has 1 to 20, particularly preferably 2 to 18, and especially 3 to 6 C atoms.

[0099] The aliphatic group can be linear, branched, or cyclic. It can also be saturated or unsaturated. Preferably, the aliphatic group is saturated.

[0100] The aliphatic group may have substituents, such as hydroxyl, C1-C5 alkoxy, cyano, nitrile, nitro and / or C5-C 20 Aryl (e.g., phenyl). If the aliphatic group has a substituent, it is preferred that the substituent is a hydroxyl group. C5-C 20 The aryl group itself can be optionally replaced by a halogen atom, a haloalkyl group, or a C1-C group. 20 Alkyl, C2-C 20 Alkenyl, hydroxyl, C1-C5 alkoxy (e.g., methoxy), amide, cyano, nitrile, and / or nitro substituents. If the substituents of the aliphatic group contain carbon atoms, these carbon atoms are not counted in the carbon number of the aliphatic group.

[0101] In a particularly preferred embodiment, R 5 and / or R 6 and / or R 7 Each group independently represents hydrogen, C1-C6 alkyl, C2-C6 alkenyl, or C3-C6 cycloalkyl, and particularly represents alkyl groups having 1, 2, or 3 carbon atoms. These groups preferably have up to three substituents. Particularly preferred are aliphatic groups R. 5 and / or R 6 and / or R 7 The aliphatic group can be methyl, ethyl, hydroxyethyl, n-propyl, isopropyl, hydroxypropyl, n-butyl, isobutyl, tert-butyl, hydroxybutyl, n-hexyl, cyclohexyl, n-octyl, n-decyl, n-dodecyl, tridecyl, isotriadecyl, tetradecyl, hexadecyl, and octadecyl. If the aliphatic group has a substituent, hydroxyl is preferred.

[0102] In another preferred embodiment, R 5 and R 6 Together with the nitrogen atoms they are bonded to, they form a ring. This ring preferably has four or more ring members, for example, five, six, seven, or eight, particularly preferably five or six. Other preferred ring members are carbon, nitrogen, oxygen, and sulfur atoms. These rings themselves may again contain substituents, such as alkyl groups. Suitable ring structures are, for example, morpholinyl, pyrrolyl, piperidinyl, imidazole, and azircyclic heptyl. Then, in a preferred embodiment, R... 7 It represents H or an alkyl group having 1 to 12 carbon atoms.

[0103] In another preferred embodiment, R 5 R 6 and / or R 7 Each of the two terms independently represents the C6-C that are optionally replaced. 12 Aryl or heteroaryl with 5 to 12 ring members that are optionally substituted.

[0104] In another preferred embodiment, R 5 R 6 and / or R 7 Each can be independently represented by an alkyl group interrupted by a heteroatom. Particularly preferred heteroatoms are oxygen and nitrogen. Thus, R 5 R 6 and / or R 7 The groups of Formula 7 are preferred independently from each other.

[0105] -(R 8 -O) p -R 9 (7)

[0106] in

[0107] R 8 This refers to an alkylene group having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms, such as ethylene, propyleneene, butylene, or mixtures thereof.

[0108] R 9 It represents hydrogen, a hydrocarbon group having 1 to 24 carbon atoms, or the formula -NR. 10 R 11 group,

[0109] p represents a number between 2 and 50, preferably between 3 and 25, and especially between 4 and 10, and

[0110] R 10 R 11 The groups, which independently represent hydrogen, are aliphatic groups having 1 to 24 carbon atoms, preferably 2 to 18 carbon atoms, aryl or heteroaryl groups having 5 to 12 ring members, and poly(alkylene oxide) groups having 1 to 50 poly(alkylene oxide) units, wherein the polyalkylene oxide units are derived from alkylene oxide units having 2 to 6 carbon atoms, or R 10 and R 11 Together with the nitrogen atoms they are bonded to, they form rings with 4, 5, 6 or more ring members.

[0111] Alternatively, preferably, R 5 R 6 and / or R 7 The groups in Formula 8 are represented independently of each other.

[0112] -[R 12 -N(R 13 )] q -H (8)

[0113] in

[0114] R 12This refers to an alkylene group having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms, such as ethylene, propylene, or mixtures thereof.

[0115] Each R 13 Independently representing hydrogen, alkyl or hydroxyalkyl groups having up to 24 carbon atoms, polyoxyalkylene-(R 8 -O) r -R 9 Or polyimide alkylene-[R] 12 -N(R 14 )2] s , where R 8 R 9 and R 12 With the meanings given above, R 14 Indicates hydrogen, alkyl or hydroxyalkyl with up to 24 carbon atoms, polyoxyalkylene-(R 8 -O) r -R 9 And r and s independently represent 1 to 50, and

[0116] q represents a number from 1 to 20, preferably from 2 to 10, such as three, four, five, or six.

[0117] The group of Formula 8 preferably contains 1 to 50, especially 2 to 20 nitrogen atoms.

[0118] Particularly preferred water-soluble amines are water-soluble alkylamines, such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, and longer-chain mono, di, and trialkylamines, provided they are water-soluble at least 1% by weight, preferably 1-5% by weight. The alkyl chain may be branched. Also suitable are low-grade polyamines, such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, their higher homologues, and mixtures thereof. Other suitable amines in this series are alkylated, particularly methylated, representatives of these low-grade polyamines, such as N,N-dimethyldiethyleneamine, N,N-dimethylpropylamine, and longer-chain and / or more highly alkylated amines with the same structural principles. Of particular suitability according to the invention are alkanolamines, such as monoethanolamine, diethanolamine, triethanolamine, diethylene glycolamine, triethylene glycolamine and higher homologues, methyldiethanolamine, ethyldiethanolamine, propyldiethanolamine, butyldiethanolamine and longer-chain alkyldiethanolamines, wherein the alkyl group may be cyclic and / or branched. Other suitable alkanolamines are dialkylethanolamines, such as dimethylethanolamine, diethylethanolamine, dipropylethanolamine, dibutylethanolamine and longer-chain dialkylethanolamines, wherein the alkyl group may also be branched and / or cyclic. Further suitable for the purposes of this invention are aminopropanol (isopropanolamine), aminobutanol, aminopentanol and higher homologues, as well as the corresponding mono- and dimethylpropanolamines and longer-chain mono- and dialkylamino alcohols. It is also particularly suitable for specific amines, such as 2-amino-2-methylpropanol (AMP), 2-dimethylamino-2-methyl-1-propanol, 2-aminopropanediol, 2-amino-2-ethylpropanediol, 2-aminobutanediol and other 2-aminoalkanols, aminoalkylamine alcohols, tris(hydroxymethyl)aminomethane, and also terminally closed representatives such as methylglycolamine, methyldiglycolamine and higher homologues, di(methylglycol)amine, di(methyldiglycol)amine and their higher homologues, as well as corresponding triamines and polyalkylene glycolamines (e.g., Jeffamine). ® Typically, and in the sense of this invention, the mixture of the above-mentioned amines is used to adjust the desired pH value.

[0119] If amine alone cannot adjust the desired pH, it may be necessary to use other suitable neutralizing agents. These are oxides and hydroxides of alkali metals and / or alkaline earth metals, such as lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, and calcium oxide.

[0120] The neutralizing agent mentioned, especially the amine, is used in the amount required to adjust the pH value of the hydraulic fluid to a desired value. This desired pH value is 7-12, preferably 8-11, and particularly preferably 9-10. The amount of neutralizing agent, especially the amine, required for this purpose is generally between 0.1-10% by weight.

[0121] The hydraulic fluid contains a polyol as component c). The polyol is used as a freezing point depressant or viscosity modifier.

[0122] Suitable freezing point depressants comprise 1-10 carbon atoms and 1-10 OH groups, preferably 1-6 carbon atoms and 1-6 OH groups, particularly 1, 2, 3, or 4 carbon atoms and 1, 2, 3, or 4 OH groups. In each case, the number of OH groups contained does not exceed the number of carbon atoms. Examples include ethylene glycol, diethylene glycol, triethylene glycol and higher polyethylene glycols, propylene glycol, dipropylene glycol and higher polypropylene glycols, corresponding methyl glycols, ethyl glycols, butyl glycols and other alkyl glycols, and alkyl propylene glycols. Glycerol, diglycerol, triglycerol and higher homologues, 1,3-propanediol and its oligomers and polymers can also be used. Mixtures of the mentioned compounds can also be used.

[0123] The concentration of the freezing point depressant used depends on the desired freezing point, which can vary significantly depending on the application and application area. A freezing point depressant of 1-50% by weight, preferably 20-50% by weight, and particularly preferably 30-45% by weight is used. A suitable freezing point depressant preferably has a freezing point of 1 to 20 mm at 50°C. 2 kinematic viscosity per s (ASTM D 7042).

[0124] Suitable viscosity modifiers are polyacrylates, polymethacrylates, and polyalkylene glycols, especially high molecular weight polyalkylene glycols. These can be obtained by anionic polymerization of epoxides of formula 5 or mixtures thereof with mono-, di-, tri-, tetra-, and polyfunctional alcohols or amines, or by metal-catalyzed polymerization.

[0125]

[0126] Where R 4 = Hydrogen, methyl, ethyl.

[0127] If multiple epoxides are available, polymerization is carried out sequentially (monomers arranged stepwise) or with a mixture of oxides (monomers arranged randomly). Suitable starting alcohols for these polyalkylene glycols include, for example, ethylene glycol, propylene glycol, trimethylolpropane, glycerol, pentaerythritol, sorbitol, and other polyols. Suitable amines are, for example, compounds referred to below as neutralizers, provided they contain an acidic NH bond. These polyalkylene glycols are typically selected not based on their molecular weight, but rather on their kinematic viscosity at 50°C, which is typically 3000 mmHg. 2 / s up to 50,000 mm 2 / s (ASTM D7042) and higher, depending on the application. The concentration of the viscosity modifier used depends on the desired viscosity and can be 1-20%, preferably 5-20%, particularly preferably 10-15%.

[0128] According to the present invention, the additives, defoamers, dyes, and antioxidants mentioned in the prior art can also be used in the hydraulic fluid. However, for the reasons mentioned above, they can be omitted in the preferred embodiment.

[0129] The hydraulic fluid according to the invention can be prepared by directly mixing these components at room temperature or a higher temperature, or by diluting a pre-prepared additive package with water, or by diluting a pre-prepared additive package with a mixture of water and a freezing point depressant. If the hydraulic fluid is prepared directly from these components, it is recommended to pre-add water and optionally a freezing point depressant, followed by the addition of other components, preferably first adding a neutralizer, then a compound of Formula 1, and then (if necessary) adding additional lubricants and additional corrosion inhibitors. Finally, other additives such as defoamers, dyes, antioxidants, and viscosity modifiers are added. If the additive package is prepared separately, water and a freezing point depressant (if it is part of the additive package) are pre-added, followed by a neutralizer, and then the other components are added in the order described above. At high viscosities, especially when the freezing point depressant is not part of the additive package, temperatures above room temperature may be required during mixing, but this temperature generally does not exceed 80-100°C. In cases of particularly high viscosity, the additive package can be diluted with water. Detailed Implementation

[0130] Example

[0131] The concentration used was selected to enable the hydraulic fluid to achieve the required corrosion protection (no corrosion at a concentration of 15%).

[0132] Example 1 (without additives) Comparative fluid A

[0133] Water 59.8%

[0134] 40.0% ethylene glycol

[0135] Triethanolamine 0.2%

[0136] Example 2 (Prior Art) - Hydraulic Fluid B

[0137] Water 49.6%

[0138] 40.0% ethylene glycol

[0139] Triethanolamine 6.3%

[0140] Monoethanolamine 1.1%

[0141] N-Methyltoluenesulfonylaminohexanoic acid 3.0%

[0142] Example 3 (Prior Art) - Hydraulic Fluid C

[0143] Water 49.4%

[0144] 40% monoethylene glycol

[0145] Triethanolamine 6.5%

[0146] Monoethanolamine 1.1%

[0147] Butyl phosphate (mono-diester mixture) 3.0%

[0148] Example 4 - Hydraulic Fluid D

[0149] Water 47.2%

[0150] 40.0% ethylene glycol

[0151] Methyldiethanolamine 8.8%

[0152] Isonononanoylaminohexanoic acid 1.0%

[0153] 10-phosphonodecanoic acid 3.0%

[0154] Example 5 - Hydraulic Fluid E

[0155] Water 51.7%

[0156] 40% monoethylene glycol

[0157] Isopropanolamine 5.3%

[0158] 10-phosphonodecanoic acid 3.0%

[0159] Example 6 - Hydraulic Fluid F

[0160] Water 48%

[0161] 40% monoethylene glycol

[0162] Triethanolamine 6.5%

[0163] Monoethanolamine 1.5%

[0164] Triazine-triaminocaproic acid 1.0%

[0165] 8-phosphonooctanoic acid 3.0%

[0166] Example 7 - Hydraulic Fluid G

[0167] Water 47.7%

[0168] 40% monoethylene glycol

[0169] 7% cyclohexylamino-N,N-diethanol

[0170] Monoethanolamine 2.3%

[0171] 10-phosphonododecanoic acid 3.0%

[0172] The concentration used was selected to provide the hydraulic fluid with the lowest possible corrosion protection, that is, for a concentration of 20... o Up to 15% by weight of hydraulic components in dH water showed no corrosion on cast iron chips (DIN 51360 / 2).

[0173] The lubrication effects of formulation DG and comparative embodiment AC according to the present invention were then tested using relevant application techniques. Lubrication characteristics were tested using the Reichert wear test, the four-ball device test (DIN 51350-1), and the Falex test (ASTM D3223-2) (see Table 1).

[0174] Reichert tests clearly showed the reduced wear of formulation DG compared to the standard AC.

[0175] Tests using a four-ball apparatus failed due to overload in formulations A (without lubricant additives) and C (water-soluble phosphate esters), while comparative example B (sulfonamide carboxylic acid) showed significantly higher wear than example DG based on phosphonocarboxylic acid according to the present invention.

[0176] According to ASTM D 3233-B, the Falex test confirmed the above-described test by demonstrating the higher load capacity (lower torque) of the specimen using the formulation of this invention.

[0177] Table 1: Application Technology Characteristics of Fluid AG

[0178]

[0179] Notes on Table 1:

[0180] 1） The appearance of a 20% solution in water, at 20°C and dH (corresponding to 350 ppm CaCO3), after 24 hours at 20°C.

[0181] 2） The appearance of a 5% solution in synthetic seawater after 24 hours at 20°C.

[0182] 3） According to Reichert's friction and wear balance (waage), the parameters are: load 15N, winding path 100 m, winding speed 1.6 m / s; material is steel coil, and wear is expressed in mm. 2 [Unit]

[0183] 4） VKA wear, parameters: load 300 N, time 1 hour, speed 1450 rpm, DIN 51350-3

[0184] 5) Falex pin-on-Vee block, torque load 500 lbs, after 30 minutes

[0185] 6） The limiting concentration of the formulation in 20° dH water at which the filter paper remains rust-free.

[0186] Furthermore, Example C is not resistant to seawater. In contrast, the hydraulic components of Examples D through G exhibited unexpectedly improved lubrication and adequate corrosion protection against iron in various application tests.

[0187] Table 2 shows the ecotoxicological data for the lubricant additives, as required by OSPAR for use in the North Sea.

[0188] Table 2

[0189]

[0190] The lubricant compound according to the invention from Example 3 showed results exceeding the required limits for biodegradability, algal and fish toxicity, and also showed generally superior values ​​compared to the prior art (see Comparative Example 1 and Comparative Example 2). Comparative Example 2, while showing improved biodegradability, was unsatisfactory in the necessary application technology tests and was therefore not used.

Claims

1. A hydraulic fluid, the hydraulic fluid comprising a) Phosphonocarboxylic acids of Formula 1 or their salts, in R 1 Indicates hydrogen or C1-C4 alkyl. X represents hydrogen, alkali metal, alkaline earth metal, or ammonium group. n represents a number from 5 to 7, and The sum (N+n+3) ranges from 8 to 14, where N is R. 1 The total number of all carbon atoms in it. b) at least one water-soluble amine c) at least one polyol, and d) Water, and The hydraulic fluid has a pH of 7 to 12.

2. The hydraulic fluid according to claim 1, comprising 0.1 to 30% by weight of a phosphonocarboxylic acid of formula 1 or a salt thereof.

3. The hydraulic fluid according to claim 1 and / or 2, wherein the hydraulic fluid comprises 35 to 70% by weight water.

4. The hydraulic fluid according to one or more of claims 1 to 3, wherein the hydraulic fluid comprises 25-50% by weight of a glycol or a polyalkylene glycol or a mixture thereof.

5. The hydraulic fluid according to one or more of claims 1 to 4, wherein Formula 1 represents 8-phosphonooctanoic acid, 10-phosphonodecanoic acid, or 10-phosphonododecanoic acid.

6. The hydraulic fluid according to one or more of claims 1 to 5, wherein the hydraulic fluid comprises at least one corrosion inhibitor selected from the group consisting of the following. a) Toluenesulfonylaminohexanoic acid or benzenesulfonylaminohexanoic acid of formula 2 Where R 2 R 3 = H or CH 3， b) Isonononanoylaminohexanoic acid of formula 3 c) Triazine-triaminohexanoic acid of Formula 4 d) Aliphatic or aromatic carboxylic acids e) Aliphatic or aromatic dicarboxylic acids.

7. The hydraulic fluid according to one or more of claims 1 to 6, wherein the hydraulic fluid comprises a lubricant for reducing friction and wear.

8. The hydraulic fluid according to one or more of claims 1 to 7, wherein the amine corresponds to formula 6. NR 5 R 6 R 7 (6) in R 5 R 6 and R 7 Choose independently the following groups. hydrogen; A hydrocarbon group having 1 to 20 carbon atoms, wherein the hydrocarbon group may have substituents, the substituents may include heteroatoms; C6-C 12 Aryl or heteroaryl having 5 to 12 ring members, which may contain substituents; Groups of Formula 7 -(R 8 -O) p -R 9 (7) in R 8 Indicates an alkylene group having 2 to 6 carbon atoms. R 9 It represents hydrogen, a hydrocarbon group having 1 to 24 carbon atoms, or the formula -NR. 10 R 11 group, p represents a number between 2 and 50, and R 10 R 11 The groups, which independently represent hydrogen, are aliphatic groups having 1 to 24 carbon atoms, aryl or heteroaryl groups having 5 to 12 ring members, and poly(alkylene oxide) groups having 1 to 50 poly(alkylene oxide) units, wherein the polyalkylene oxide units are derived from alkylene oxide units having 2 to 6 carbon atoms. Or R 10 and R 11 Together with the nitrogen atoms they are bonded to, they form rings with 4, 5, 6 or more ring members; Groups of Formula 8 -[R 12 -N(R 13 )] q -H (8) in R 12 Indicates an alkylene group having 2 to 6 carbon atoms. Each R 13 Independently representing hydrogen, alkyl or hydroxyalkyl groups having up to 24 carbon atoms, polyoxyalkylene-(R 8 -O) r -R 9 Or polyimide alkylene-[R] 12 -N(R 14 )2] s , where R 8 R 9 and R 12 With the meanings given above, R 14 Indicates hydrogen, alkyl or hydroxyalkyl with up to 24 carbon atoms, polyoxyalkylene-(R 8 -O) r -R 9 And r and s independently represent 1 to 50, and q represents a number from 1 to 20; Or R 5 and R 6 They form rings together with the nitrogen atoms to which they are bonded; The prerequisite is that not all groups R 5 R 6 and R 7 Both refer to hydrogen.

9. The hydraulic fluid according to one or more of claims 1 to 8, wherein the amine is an alkanolamine and preferably selected from the group consisting of: monoethanolamine, diethanolamine, triethanolamine, diethylene glycolamine, triethylene glycolamine, methyldiethanolamine, ethyldiethanolamine, propyldiethanolamine, butyldiethanolamine, dimethylethanolamine, diethylethanolamine, dipropylethanolamine, dibutylethanolamine and longer-chain dialkylethanolamines, aminopropanol (isopropanolamine), aminobutanol, aminopentanol, mono- and dimethylpropanolamine, 2-amino-2-methylpropanol (AMP), 2-dimethylamino-2-methyl-1-propanol, 2-aminopropanediol, 2-amino-2-ethylpropanediol and 2-aminobutanediol.

10. The hydraulic fluid according to one or more of claims 1 to 9, comprising a thickener selected from the group consisting of: polyacrylate, polymethacrylate, polyethylene glycol, polypropylene glycol, and polyalkylene glycol.

11. The following a) uses of phosphonocarboxylic acids of Formula 1 or their salts for improving the lubrication of hydraulic fluids. in R 1 Indicates hydrogen or C1-C4 alkyl. X represents hydrogen, alkali metal, alkaline earth metal, or ammonium group. n represents a number from 5 to 7, and The sum (N+n+3) ranges from 8 to 14, where N is R. 1 The total number of all carbon atoms in the hydraulic fluid. b) at least one water-soluble amine c) at least one polyalkylene glycol, and d) Water, and The hydraulic fluid has a pH of 7 to 12.

12. A method for improving the lubrication properties of a water-based hydraulic fluid, wherein a compound of formula 1 is added to the hydraulic fluid. in R 1 Indicates hydrogen or C1-C4 alkyl. X represents hydrogen, alkali metal, alkaline earth metal, or ammonium group. n represents a number from 5 to 7, and The sum (N+n+3) ranges from 8 to 14, where N is R. 1 The total number of all carbon atoms in it; The hydraulic fluid includes b) At least one water-soluble amine c) at least one polyalkylene glycol, and d) Water, and It has a pH of 7 to 12.

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