Hydraulic oil and preparation method and application thereof

Abstract

The invention relates to the technical field of hydraulic oil, and discloses hydraulic oil as well as a preparation method and application thereof. The hydraulic oil comprises the following components in parts by weight: 70 to 100 parts of base oil, 0 to 10 parts of a tackifier, 0.2 to 5 parts of an antioxidant, 0.005 to 2 parts of a corrosion inhibitor, 0.01 to 2 parts of an anti-wear reagent at extreme pressure, 0.01 to 1 part of a demulsifier, 0.05 to 5 parts of an anti-hydrolysis agent and 0.001 to 0.01 part of an anti-foaming agent, wherein the base oil is selected from saturated fatty acid ester-1 and / or oil-soluble polyalkylene glycol, the saturated fatty acid ester-1 comprises a compound as shown in a structural formula (i) and / or (ii), and a molecular chain of the oil-soluble polyalkylene glycol contains an epoxypropane structural unit and an epoxybutane structural unit. The types and contents of the base oil and the additive are limited, and the base oil and the additive have a mutual synergistic effect, so that the provided hydraulic oil has excellent biodegradability, lubricating oil performance, hydrolytic stability, rubber compatibility and oxidation stability.

Description

Technical Field

[0001] This invention relates to the field of hydraulic oil technology, specifically to a hydraulic oil, its preparation method, and its application. Background Technology

[0002] Hydraulic oil, as the "blood" of mechanical equipment, plays a vital role in energy transfer, lubrication, corrosion prevention, rust prevention, and cooling. With the development of mechanical equipment and hydraulic technology, the performance requirements for hydraulic oil are becoming increasingly stringent. In addition to meeting basic usage requirements, hydraulic oil must also possess excellent biodegradability, oxidation stability, lubrication properties, rubber compatibility, and hydrolytic stability.

[0003] Currently, mineral-based hydraulic oils are difficult to biodegrade, which limits their use in environmentally sensitive fields such as ships, ports, agricultural machinery, and dams.

[0004] The development of environmentally friendly hydraulic oil can meet the requirements of environmentally sensitive hydraulic fields while replacing ordinary mineral-based hydraulic oil to meet the usage requirements of general industrial equipment. The developed environmentally friendly hydraulic oil has excellent biodegradability, lubrication performance, hydrolysis resistance, corrosion resistance and water separation performance. Its comprehensive performance is excellent and can meet the usage requirements of various hydraulic systems.

[0005] CN109233953A discloses a flame-retardant and biodegradable environmentally friendly hydraulic oil, which is composed of 100 parts by weight of polyol ester base oil, 0.01-0.05 parts by weight of viscosity modifier, 0.5-1 parts by weight of phenolic antioxidant, 1-10 parts by weight of anti-wear agent, 0.1-1.5 parts by weight of rust inhibitor, 0.01-0.05 parts by weight of acrylate-ether copolymer antifoaming agent, and 0.1-0.5 parts by weight of four-arm PEG mercapto. Although this hydraulic oil has excellent lubricity, high and low temperature stability, and outstanding biodegradability; good air release properties, rubber compatibility, and complete compatibility with mineral oil, it contains a large number of unsaturated functional groups, resulting in poor oxidation stability and insufficient oxidation life.

[0006] Therefore, a new type of hydraulic oil is urgently needed. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of poor biodegradability, lubricating performance, hydrolytic stability, rubber compatibility, and oxidation stability of hydraulic oils in the prior art, and to provide a hydraulic oil, its preparation method, and its application.

[0008] To achieve the above objectives, the first aspect of the present invention provides a hydraulic oil, wherein the hydraulic oil comprises: 70-100 parts by weight of base oil, 0-10 parts by weight of viscosity improver, 0.2-5 parts by weight of antioxidant, 0.005-2 parts by weight of corrosion inhibitor, 0.01-2 parts by weight of extreme pressure anti-wear agent, 0.01-1 parts by weight of demulsifier, 0.05-5 parts by weight of anti-hydrolysis agent, and 0.001-0.01 parts by weight of antifoaming agent;

[0009] The base oil is selected from saturated fatty acid ester-1 and / or oil-soluble polyalkylene glycol, wherein the saturated fatty acid ester-1 comprises compounds shown in structural formulas (i) and / or (ii), and the molecular chain of the oil-soluble polyalkylene glycol contains propylene oxide structural units and butane oxide structural units.

[0010] R1, R2, R3 and R4 are each independently an alkyl group with 5-11 carbon atoms;

[0011] Where R is an alkyl group with 5-9 carbon atoms, R' is a hydrocarbon group with 4-6 carbon atoms, R" is a hydrocarbon group with 3-5 carbon atoms, and m is 1-6.

[0012] A second aspect of the present invention provides a method for preparing hydraulic oil, wherein the method includes:

[0013] The base oil, viscosity modifier, antioxidant, corrosion inhibitor, extreme pressure anti-wear agent, demulsifier, anti-hydrolysis agent and anti-foaming agent are mixed and dehydrated to obtain hydraulic oil;

[0014] The base oil is selected from saturated fatty acid ester-1 and / or oil-soluble polyalkylene glycol, wherein the saturated fatty acid ester-1 comprises compounds shown in structural formulas (i) and / or (ii), and the molecular chain of the oil-soluble polyalkylene glycol contains propylene oxide structural units and butane oxide structural units.

[0015] Among them, R1, R2, R3 and R4 are each independently an alkyl group with 5-11 carbon atoms;

[0016] Wherein, R is an alkyl group with 5-9 carbon atoms, R' is a hydrocarbon group with 4-6 carbon atoms, R" is a hydrocarbon group with 3-5 carbon atoms, and m is 1-6.

[0017] The third aspect of this invention provides the application of hydraulic oil prepared by the above-described method in mechanical equipment such as ships, ports, agriculture, and dams.

[0018] Through the above technical solution, the technical solution provided by the present invention achieves the following beneficial effects:

[0019] The hydraulic oil provided by this invention comprises a base oil and additives, wherein the base oil is selected from saturated fatty acid ester-1 and / or oil-soluble polyalkylene glycol. By limiting the types and contents of the base oil and additives, and by ensuring the synergistic effect between the base oil and additives, the provided hydraulic oil exhibits excellent biodegradability (82-96%) and lubricating properties (kinematic viscosity at 40°C, 43.4-47.2 mm). 2 / s, water separation performance 19-23min, oxidation life >2900h, FZG gear failure, ≥12 grade), hydrolytic stability (total acidity of water layer, 0.9-2.9mgKOH / g), rubber compatibility (FKM rubber volume change rate 7.7-9.1%) and oxidation stability (copper strip corrosion 1a-1b), can be used in mechanical equipment such as ships, ports, agriculture and dams where environmental protection, lubricating oil performance, hydrolytic stability, rubber compatibility and oxidation stability are required. Detailed Implementation

[0020] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0021] The first aspect of this invention provides a hydraulic oil, wherein the hydraulic oil comprises: 70-100 parts by weight of base oil, 0-10 parts by weight of viscosity modifier, 0.2-5 parts by weight of antioxidant, 0.005-2 parts by weight of corrosion inhibitor, 0.01-2 parts by weight of extreme pressure anti-wear agent, 0.01-1 parts by weight of demulsifier, 0.05-5 parts by weight of anti-hydrolysis agent, and 0.001-0.01 parts by weight of antifoaming agent;

[0022] The base oil is selected from saturated fatty acid ester-1 and / or oil-soluble polyalkylene glycol, wherein the saturated fatty acid ester-1 comprises compounds shown in structural formulas (i) and / or (ii), and the molecular chain of the oil-soluble polyalkylene glycol contains propylene oxide structural units and butane oxide structural units.

[0023] Among them, R1, R2, R3 and R4 are each independently an alkyl group with 5-11 carbon atoms;

[0024] Wherein, R is an alkyl group with 5-9 carbon atoms, R' is a hydrocarbon group with 4-6 carbon atoms, R" is a hydrocarbon group with 3-5 carbon atoms, and m is 1-6.

[0025] In this invention, when the base oil meets the above conditions and the hydraulic oil contains the above components and the amount of each component meets the above range, a good overall interaction can be achieved, so that the hydraulic oil has high biodegradability, while also having excellent lubricating properties, hydrolytic stability, rubber compatibility and oxidation stability.

[0026] According to the present invention, the oil-soluble polyalkylene glycol can be commercially available from Dow Chemical Company, model OSP-32 or OSP-46.

[0027] According to the present invention, the hydraulic oil comprises: 75-100 parts by weight of base oil, 0-9 parts by weight of viscosity improver, 1-4 parts by weight of antioxidant, 0.05-1 parts by weight of corrosion inhibitor, 0.05-1.5 parts by weight of extreme pressure anti-wear agent, 0.03-0.3 parts by weight of demulsifier, 0.2-4 parts by weight of anti-hydrolysis agent and 0.001-0.008 parts by weight of antifoaming agent.

[0028] According to the present invention, the molecular chain of the oil-soluble polyalkylene glycol further contains alkoxy-terminated groups, preferably having 1-18 carbon atoms in the alkoxy-terminated groups, more preferably having 4-12 carbon atoms in the alkoxy-terminated groups;

[0029] According to the present invention, based on the total amount of the oil-soluble polyalkylene glycol, the content of propylene oxide structural units is 40-60 wt% and the content of butylene oxide structural units is 60-40 wt%.

[0030] According to the present invention, the weight ratio of the saturated fatty acid ester-1 to the oil-soluble polyalkylene glycol is (11-99):1, preferably (19-99):1.

[0031] According to the present invention, the oil-soluble polyalkylene glycol has a kinematic viscosity of 32-46 mm at 40°C. 2 / s.

[0032] According to the present invention, the thickener is selected from saturated fatty acid ester-2 and / or polymethacrylate. The saturated fatty acid ester-2 has a kinematic viscosity of 220-320 mmHg at 40°C. 2 / s, wherein the saturated fatty acid ester-2 is a dipentaerythritol ester, which is commercially available from Croda Ltd., UK; the polymethacrylate has a kinematic viscosity of 1500-1700 mm at 100°C. 2 / s.

[0033] According to the present invention, the antioxidant is selected from at least one of hindered phenolic antioxidants, aromatic amine antioxidants, and peroxide decomposition antioxidants.

[0034] According to the present invention, the hindered phenolic antioxidant is selected from at least one of alkylphenols, aminoalkylphenols, alkylphenol polymers, alkyl-substituted hindered phenolic esters, heteroatom phenols, tetrasubstituted pentaerythritol esters, and sulfurized hindered phenolic esters, preferably 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4-[(4,6-dioctylthio-1,3,5-triazin-2-yl)amino]-2,6-di-tert-butylphenol, and ... Butylphenol, 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2'-thionyl glycol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, C3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate 13-15 At least one of branched and straight-chain alkyl esters and octadecanoic acid ester of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0035] According to the present invention, the aromatic amine antioxidant is selected from at least one of nonyl-N-(nonylphenyl)aniline, diisooctyl diphenylamine, 4,4'-di(phenylisopropyl)diphenylamine, octylbutyl diphenylamine, N-phenyl-α-naphthylamine and octyl-N-phenyl-α-naphthylamine.

[0036] According to the present invention, the peroxide decomposition agent antioxidant is selected from alkylphenyl phosphites and / or thioesters, preferably at least one of tris(2,4-di-tert-butylphenyl) phosphite, pentaerythritol tetra(3-lauryl thiopropionate), thiocarbamate and didodecyl thiodipropionate.

[0037] According to the present invention, the corrosion inhibitor is selected from at least one of benzotriazole derivatives, 2-mercaptobenzothiazole, and N,N-disalynyl-1,2-diaminopropane, preferably the benzotriazole derivative is selected from at least one of 5-methylbenzotriazole, IRGAMET 39, CUVAN 303, and RC 8239; IRGAMET 39 is commercially available from BASF; CUVAN 303 is commercially available from Luoyang Pacific United Petrochemical Co., Ltd.; and RC 8239 is commercially available from Lanxess Chemical Company.

[0038] According to the present invention, the extreme pressure anti-wear agent is selected from at least one of dialkyl dithiocarbamate, IRGALUBE 353, PSAIL 3530, IRGALUBE 349, RC3760, and triphenyl thiophosphate. IRGALUBE 353 is commercially available from BASF; PSAIL 3530 is commercially available from Luoyang Pacific United Petrochemical Co., Ltd.; IRGALUBE 349 is commercially available from BASF; and RC3760 is commercially available from Lanxess Chemical Company.

[0039] According to the present invention, the demulsifier is an ethylene oxide-propylene oxide block polyether.

[0040] According to the present invention, the anti-hydrolysis agent is selected from carbodiimide and / or polyalkylene glycol, which can be commercially available from Dow Chemical Company.

[0041] According to the present invention, the antifoaming agent is selected from polydimethyl silicone oil and / or fluorosilicone oil, and the polydimethyl silicone oil can be commercially available from the Synthetic Grease Branch of Sinopec Lubricating Oil Co., Ltd.

[0042] According to the present invention, the antioxidant is a mixture of hindered phenolic antioxidants, aromatic amine antioxidants and peroxide decomposition antioxidants, wherein the weight ratio of the hindered phenolic antioxidants, aromatic amine antioxidants and peroxide decomposition antioxidants is (3-5):(0.5-2):0.05.

[0043] According to the present invention, the corrosion inhibitor is a mixture of benzotriazole derivative, 2-mercaptobenzothiazole and N,N-disalynyl-1,2-diaminopropane, wherein the weight ratio of the benzotriazole derivative, 2-mercaptobenzothiazole and N,N-disalynyl-1,2-diaminopropane is (94-99):(0.2-5):1.

[0044] According to the present invention, the ethylene oxide-propylene oxide block polyether has a cloud point of 33-37°C and an acid value of 0-2 mg KOH / g.

[0045] According to the present invention, the anti-hydrolysis agent is a mixture of carbodiimide and polyalkylene glycol, wherein the weight ratio of carbodiimide to polyalkylene glycol is (0.01-0.9):1.

[0046] According to the present invention, the antifoaming agent is a mixture of polydimethyl silicone oil and fluorosilicone oil, wherein the weight ratio of polydimethyl silicone oil to fluorosilicone oil is (0.5-1):1.

[0047] In this invention, when the above-mentioned substances do not meet the above-mentioned range and conditions, they cannot achieve a good overall interaction, and the hydraulic oil of this invention cannot be obtained and the technical problems of this invention cannot be overcome.

[0048] A second aspect of the present invention provides a method for preparing hydraulic oil, wherein the method includes:

[0049] The base oil, viscosity modifier, antioxidant, corrosion inhibitor, extreme pressure anti-wear agent, demulsifier, anti-hydrolysis agent and anti-foaming agent are mixed and dehydrated to obtain hydraulic oil;

[0050] The base oil is selected from saturated fatty acid ester-1 and / or oil-soluble polyalkylene glycol, wherein the saturated fatty acid ester-1 comprises compounds shown in structural formulas (i) and / or (ii), and the molecular chain of the oil-soluble polyalkylene glycol contains propylene oxide structural units and butane oxide structural units.

[0051] R1, R2, R3 and R4 are each independently an alkyl group with 5-11 carbon atoms;

[0052] Where R is an alkyl group with 5-9 carbon atoms, R' is a hydrocarbon group with 4-6 carbon atoms, R" is a hydrocarbon group with 3-5 carbon atoms, and m is 1-6.

[0053] According to the present invention, the compound represented by structural formula (i) is hexanoic acid, heptanoic acid, octanoic acid, isooctanoic acid, decanoic acid, lauric acid, and pentaerythritol. These compounds are subjected to esterification at 130°C-250°C with a stannous oxalate catalyst to obtain saturated fatty acid ester-I. The mass ratio of hexanoic acid, heptanoic acid, octanoic acid, isooctanoic acid, decanoic acid, lauric acid, stannous oxalate, and pentaerythritol is (0.06-0.15):(0.001-0.01):(1.35-1.76):(2.60-2.71):(1.03-1.32):(0.008-0.03):(0.001-0.003):1.

[0054] According to the present invention, the compound represented by structural formula (ii) is adipic acid, octanoic acid, decanoic acid, and neopentyl glycol. An esterification reaction is carried out at 130-230°C using tetrabutyl titanate as a catalyst to obtain saturated fatty acid ester-II, wherein the mass ratio of adipic acid, octanoic acid, decanoic acid, tetrabutyl titanate, and neopentyl glycol is (0.7-0.9):(0.75-0.96):(0.45-0.64):(0.001-0.003):1.

[0055] According to the present invention, the dehydration conditions include: a temperature of 80-110°C, a pressure of -0.094 MPa to -0.1 MPa, and a time of 1-3 hours.

[0056] According to the present invention, the dehydration conditions include: a temperature of 85-100°C, a pressure of -0.098 MPa to -0.1 MPa, and a time of 1.5-2 h.

[0057] According to the present invention, the blending also includes a filtration process, which includes three-stage filtration using a three-stage filter element with a diameter of 12μm-7μm-3μm.

[0058] The third aspect of this invention provides the application of hydraulic oil prepared by the above-described method in mechanical equipment such as ships, ports, agriculture, and dams.

[0059] The present invention will be described in detail below through embodiments. In the following embodiments,

[0060] The biodegradability of the hydraulic fluid was determined according to the OECD 301F method;

[0061] The viscosity index of the hydraulic oil was measured according to GB / T 1995;

[0062] The pour point of hydraulic oil shall be determined in accordance with GB / T 3535;

[0063] The water separation performance of hydraulic oil was measured according to GB / T 7305;

[0064] The copper strip corrosion resistance of hydraulic oil was tested according to GB / T 5096;

[0065] The hydrolytic stability of the hydraulic oil was determined according to ASTM D2619.

[0066] The gear failure level energy of hydraulic oil can be measured using the SH / T 0306 method;

[0067] The oxidation life of the hydraulic oil was determined according to ISO 4263-3.

[0068] The rubber compatibility content of the hydraulic oil was determined according to the method in GB / T 14832.

[0069] The ethylene oxide-propylene oxide block polyether was purchased from Shanghai Yucheng Chemical Co., Ltd., model number Enable394.

[0070] The polymethyl methacrylate was purchased from Evonik Industries, model number VISCOPLEX 8-310;

[0071] IRGAMET 39 was purchased from BASF.

[0072] CUVAN 303 was purchased from Luoyang Pacific United Petrochemical Co., Ltd.

[0073] RC 8239 was purchased from Lanxess Chemical Company;

[0074] IRGALUBE 353 was purchased from BASF.

[0075] PSAIL 3530 was purchased from Luoyang Pacific United Petrochemical Co., Ltd.

[0076] IRGALUBE349 was purchased from BASF.

[0077] RC3760 was purchased from Lanxess Chemical Company;

[0078] All raw materials used in the examples and comparative examples are commercially available products.

[0079] Preparation Example 1

[0080] Saturated fatty acid ester I was prepared by esterification of hexanoic acid, heptanoic acid, octanoic acid, isooctanoic acid, decanoic acid, lauric acid, and pentaerythritol at 130-250 °C using stannous oxalate catalyst, wherein the mass ratio of hexanoic acid, heptanoic acid, octanoic acid, isooctanoic acid, decanoic acid, lauric acid, stannous oxalate, and pentaerythritol was 0.1:0.002:1.5:2.7:1.3:0.02:0.002:1.

[0081] Preparation Example 2

[0082] Adipic acid, octanoic acid, decanoic acid, and neopentyl glycol were esterified at 130-230℃ using tetrabutyl titanate as a catalyst to obtain saturated fatty acid ester-II. The mass ratio of adipic acid, octanoic acid, decanoic acid, tetrabutyl titanate, and neopentyl glycol was 0.8:0.8:0.5:0.002:1.

[0083] Example 1

[0084] The base oil, viscosity modifier, antioxidant, corrosion inhibitor, extreme pressure anti-wear agent, demulsifier, anti-hydrolysis agent and anti-foaming agent are mixed and dehydrated to obtain hydraulic oil;

[0085] The base oil consisted of 100 parts by weight of saturated fatty acid ester-II and oil-soluble polyalkylene glycol, with a weight ratio of saturated fatty acid ester-II (Preparation Example 2) to oil-soluble polyalkylene glycol of 99:1. The kinematic viscosity of the oil-soluble polyalkylene glycol at 40°C was 32 mm. 2 / s, wherein the oil-soluble polyalkylene glycol contains 50 wt% propylene oxide structural units and 50 wt% butane oxide structural units, and also contains alkoxy-terminated groups with 12 carbon atoms; the tackifier is 0 parts by weight; the antioxidant is 1.8 parts by weight of isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, N-phenyl-α-naphthylamine, and thiocarbamate, with the weight ratio of isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, N-phenyl-α-naphthylamine, and thiocarbamate being 4:1.6:0.05; and the corrosion inhibitor is 0.2 parts by weight of 5-methylbenzotriazole, 2-mercaptobenzothiazole, N,N-disalynyl-1,2-diaminopropane, 5-methylbenzotriazole, and 2-mercaptobenzothiazole. The hydraulic oil was obtained by dehydrating the following components: azole and N,N-disalynyl-1,2-diaminopropane in a weight ratio of 96:2.5:1; dialkyl dithiocarbamate as the extreme pressure anti-wear agent; ethylene oxide-propylene oxide block polyether as the demulsifier (with a cloud point of 35℃ and an acid value of 0.03 mg KOH / g); carbodiimide and polyalkylene glycol as the anti-hydrolysis agents (with a weight ratio of carbodiimide to polyalkylene glycol of 0.8:1); and polydimethyl silicone oil and fluorosilicone oil as the antifoaming agents (with a weight ratio of polydimethyl silicone oil to fluorosilicone oil of 0.5:1). The mixture was dehydrated at 90℃ and -0.099 MPa for 2 hours.

[0086] Examples 2-5

[0087] Lubricating oils were prepared according to the method of Example 1, except that the physical properties, types, and amounts of the raw materials in the hydraulic oils were different from those in Example 1, as shown in Table 1; the dehydration and blending conditions were also different, as shown in Table 1. Hydraulic oils A2-A5 were prepared respectively.

[0088] Comparative Example 1

[0089] Hydraulic oil was prepared according to the method of Example 1, except that the base oil was an unsaturated fatty acid ester (trimethylolpropane oleate), resulting in hydraulic oil D1.

[0090] Comparative Example 2

[0091] The lubricating oil was prepared according to the method of Example 1, except that the weight ratio of saturated fatty acid ester to oil-soluble polyalkylene glycol was 5:1, resulting in hydraulic oil D2.

[0092] Comparative Example 3

[0093] Hydraulic oil was prepared according to the method of Example 1, except that the weight ratio of 3,5-di-tert-butyl-4-hydroxyphenylpropionate isooctyl ester, N-phenyl-α-naphthylamine and thiocarbamate was 10:0.1:0.01, resulting in hydraulic oil D3.

[0094] Comparative Example 4

[0095] Hydraulic oil was prepared according to the method of Example 1, except that the weight ratio of 5-methylbenzotriazole, 2-mercaptobenzothiazole and N,N-disalynyl-1,2-diaminopropane was 1:9:90, resulting in hydraulic oil D4.

[0096] The properties of the hydraulic oils prepared in the examples and comparative examples were tested, and the test results are shown in Table 2.

[0097] Table 1

[0098]

[0099]

[0100]

[0101] Table 1 (continued)

[0102]

[0103]

[0104]

[0105] Table 2

[0106]

[0107] Table 2 (continued)

[0108]

[0109]

[0110] The hydraulic oil provided by this invention comprises a base oil and additives, wherein the base oil is selected from saturated fatty acid ester 1 and / or oil-soluble polyalkylene glycol. By limiting the types and contents of the base oil and additives, and by ensuring the synergistic effect between the base oil and additives, the provided hydraulic oil exhibits excellent biodegradability (82-96%) and lubricating properties (kinematic viscosity at 40°C, 43.4-47.2 mm). 2 / s, water separation performance 19-23min, oxidation life >2900h, FZG gear failure, ≥12 grade), hydrolytic stability (total acidity of water layer, 0.9-2.9mgKOH / g), rubber compatibility (FKM rubber volume change rate 7.7-9.1%) and oxidation stability (copper strip corrosion 1a-1b), can be used in mechanical equipment such as ships, ports, agriculture and dams where environmental protection, lubricating oil performance, hydrolytic stability, rubber compatibility and oxidation stability are required.

[0111] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A hydraulic oil, characterized in that, The hydraulic oil comprises: 70-100 parts by weight of base oil, 0-10 parts by weight of viscosity modifier, 0.2-5 parts by weight of antioxidant, 0.005-2 parts by weight of corrosion inhibitor, 0.01-2 parts by weight of extreme pressure anti-wear agent, 0.01-1 parts by weight of demulsifier, 0.05-5 parts by weight of anti-hydrolysis agent and 0.001-0.01 parts by weight of antifoaming agent; The base oil is selected from saturated fatty acid ester-1 and / or oil-soluble polyalkylene glycol, wherein the saturated fatty acid ester-1 comprises compounds shown in structural formulas (i) and / or (ii), and the molecular chain of the oil-soluble polyalkylene glycol contains propylene oxide structural units and butane oxide structural units. R1, R2, R3 and R4 are each independently an alkyl group with 5-11 carbon atoms; Where R is an alkyl group with 5-9 carbon atoms, R' is a hydrocarbon group with 4-6 carbon atoms, R" is a hydrocarbon group with 3-5 carbon atoms, and m is 1-6.

2. The hydraulic oil according to claim 1, wherein, The hydraulic oil comprises: 75-100 parts by weight of base oil, 0-9 parts by weight of viscosity improver, 1-4 parts by weight of antioxidant, 0.05-1 parts by weight of corrosion inhibitor, 0.05-1.5 parts by weight of extreme pressure anti-wear agent, 0.03-0.3 parts by weight of demulsifier, 0.2-4 parts by weight of anti-hydrolysis agent and 0.001-0.008 parts by weight of antifoaming agent; Preferably, the molecular chain of the oil-soluble polyalkylene glycol further contains alkoxy-terminated groups, and preferably the number of carbon atoms in the alkoxy-terminated groups is 1-18; Preferably, based on the total amount of the oil-soluble polyalkylene glycol, the content of propylene oxide structural units is 40-60 wt% and the content of butylene oxide structural units is 60-40 wt%. Preferably, the weight ratio of the saturated fatty acid ester-1 to the oil-soluble polyalkylene glycol is (11-99):1, more preferably (19-99):

1.

3. The hydraulic oil according to claim 1 or 2, wherein, The oil-soluble polyalkylene glycol has a kinematic viscosity of 32-46 mmHg at 40°C. 2 / s; Preferably, the thickener is selected from saturated fatty acid ester-2 and / or polymethacrylate; Preferably, the antioxidant is selected from at least one of hindered phenolic antioxidants, aromatic amine antioxidants, and peroxide decomposition antioxidants; Preferably, the corrosion inhibitor is selected from at least one of benzotriazole derivatives, 2-mercaptobenzothiazole and N,N-disalynyl-1,2-diaminopropane, and more preferably, the benzotriazole derivative is selected from at least one of 5-methylbenzotriazole, IRGAMET 39, CUVAN 303 and RC 8239; Preferably, the extreme pressure anti-wear agent is selected from at least one of dialkyl dithiocarbamate, IRGALUBE 353, PSAIL 3530, IRGALUBE 349, RC3760 and triphenyl thiophosphate; Preferably, the demulsifier is an ethylene oxide-propylene oxide block polyether; Preferably, the anti-hydrolysis agent is selected from carbodiimide and / or polyalkylene glycol; Preferably, the antifoaming agent is selected from polydimethyl silicone oil and / or fluorosilicone oil.

4. The hydraulic oil according to any one of claims 1-3, wherein, The antioxidant is a mixture of hindered phenolic antioxidants, aromatic amine antioxidants and peroxide decomposition antioxidants, wherein the weight ratio of the hindered phenolic antioxidants, aromatic amine antioxidants and peroxide decomposition antioxidants is (3-5):(0.5-2):0.05; Preferably, the corrosion inhibitor is a mixture of benzotriazole derivative, 2-mercaptobenzothiazole and N,N-disalynyl-1,2-diaminopropane, wherein the weight ratio of the benzotriazole derivative, 2-mercaptobenzothiazole and N,N-disalynyl-1,2-diaminopropane is (94-99):(0.2-5):1; Preferably, the ethylene oxide-propylene oxide block polyether has a cloud point of 33-37℃ and an acid value of 0-2 mgKOH / g; Preferably, the anti-hydrolysis agent is a mixture of carbodiimide and polyalkylene glycol, wherein the weight ratio of carbodiimide to polyalkylene glycol is (0.01-0.9):1; Preferably, the antifoaming agent is a mixture of polydimethyl silicone oil and fluorosilicone oil, wherein the weight ratio of polydimethyl silicone oil to fluorosilicone oil is (0.5-1):

1.

5. A method for preparing hydraulic oil, characterized in that, The method comprises: The base oil, viscosity modifier, antioxidant, corrosion inhibitor, extreme pressure anti-wear agent, demulsifier, anti-hydrolysis agent and anti-foaming agent are mixed and dehydrated to obtain hydraulic oil; The base oil is selected from saturated fatty acid ester-1 and / or oil-soluble polyalkylene glycol, wherein the saturated fatty acid ester-1 comprises compounds shown in structural formulas (i) and / or (ii), and the molecular chain of the oil-soluble polyalkylene glycol contains propylene oxide structural units and butane oxide structural units. R1, R2, R3 and R4 are each independently an alkyl group with 5-11 carbon atoms; Where R is an alkyl group with 5-9 carbon atoms, R' is a hydrocarbon group with 4-6 carbon atoms, R" is a hydrocarbon group with 3-5 carbon atoms, and m is 1-6.

6. The preparation method according to claim 5, wherein, The hydraulic oil comprises: 90-100 parts by weight of base oil, 0-10 parts by weight of viscosity modifier, 0.2-5 parts by weight of antioxidant, 0.005-2 parts by weight of corrosion inhibitor, 0.01-2 parts by weight of extreme pressure anti-wear agent, 0.01-1 parts by weight of demulsifier, 0.05-5 parts by weight of anti-hydrolysis agent and 0.001-0.01 parts by weight of antifoaming agent; Preferably, the hydraulic oil comprises: 91-100 parts by weight of base oil, 0-9 parts by weight of viscosity modifier, 1-4 parts by weight of antioxidant, 0.05-1 parts by weight of corrosion inhibitor, 0.05-1.5 parts by weight of extreme pressure anti-wear agent, 0.03-0.3 parts by weight of demulsifier, 0.2-4 parts by weight of anti-hydrolysis agent and 0.001-0.008 parts by weight of antifoaming agent; Preferably, the weight ratio of the saturated fatty acid ester-1 to the oil-soluble polyalkylene glycol is (11-99):1, more preferably (19-99):1; Preferably, the molecular chain of the oil-soluble polyalkylene glycol further contains alkoxy-terminated groups, and preferably the number of carbon atoms in the alkoxy-terminated groups is 1-18; Preferably, based on the total amount of the oil-soluble polyalkylene glycol, the content of propylene oxide structural units is 40-60 wt% and the content of butylene oxide structural units is 60-40 wt%.

7. The preparation method according to claim 5 or 6, wherein, The oil-soluble polyalkylene glycol has a kinematic viscosity of 32-46 mmHg at 40°C. 2 / s; Preferably, the thickener is selected from saturated fatty acid ester-2 and / or polymethacrylate; Preferably, the antioxidant is selected from at least one of hindered phenolic antioxidants, aromatic amine antioxidants, and peroxide decomposition antioxidants; Preferably, the corrosion inhibitor is selected from at least one of benzotriazole derivatives, 2-mercaptobenzothiazole and N,N-disalynyl-1,2-diaminopropane, and more preferably, the benzotriazole derivative is selected from at least one of 5-methylbenzotriazole, IRGAMET 39, CUVAN 303 and RC 8239; Preferably, the extreme pressure anti-wear agent is selected from at least one of dialkyl dithiocarbamate, IRGALUBE 353, PSAIL 3530, IRGALUBE 349, RC3760 and triphenyl thiophosphate; Preferably, the demulsifier is an ethylene oxide-propylene oxide block polyether; Preferably, the anti-hydrolysis agent is selected from carbodiimide and / or polyalkylene glycol; Preferably, the antifoaming agent is selected from polydimethyl silicone oil and / or fluorosilicone oil.

8. The preparation method according to any one of claims 5-7, wherein, The antioxidant is a mixture of hindered phenolic antioxidants, aromatic amine antioxidants and peroxide decomposition antioxidants, wherein the weight ratio of the hindered phenolic antioxidants, aromatic amine antioxidants and peroxide decomposition antioxidants is (3-5):(0.5-2):0.05; Preferably, the corrosion inhibitor is a mixture of benzotriazole derivative, 2-mercaptobenzothiazole and N,N-disalynyl-1,2-diaminopropane, wherein the weight ratio of the benzotriazole derivative, 2-mercaptobenzothiazole and N,N-disalynyl-1,2-diaminopropane is (94-99):(0.2-5):1; Preferably, the ethylene oxide-propylene oxide block polyether has a cloud point of 33-37℃ and an acid value of 0-2 mgKOH / g; Preferably, the anti-hydrolysis agent is a mixture of carbodiimide and polyalkylene glycol, wherein the weight ratio of carbodiimide to polyalkylene glycol is (0.01-0.9):1; Preferably, the antifoaming agent is a mixture of polydimethyl silicone oil and fluorosilicone oil, wherein the weight ratio of polydimethyl silicone oil to fluorosilicone oil is (0.5-1):

1.

9. The preparation method according to any one of claims 5-8, wherein, The dehydration conditions include: a temperature of 80-110℃, a pressure of -0.094MPa to -0.1MPa, and a time of 1-3h; Preferably, the dehydration conditions include: a temperature of 85-100℃, a pressure of -0.098MPa to -0.1MPa, and a time of 1.5-2h.

10. The hydraulic oil prepared by any one of claims 5-9 is used in mechanical equipment such as ships, ports, agriculture, and dams.

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