Long-life energy-saving hydraulic oil and preparation method thereof

Abstract

The invention relates to the technical field of hydraulic system media, in particular to long-life energy-saving hydraulic oil and a preparation method thereof. The long-life energy-saving hydraulic oil is prepared from the following raw materials in parts by mass: 90 to 95 parts of API II type base oil, 2 to 4 parts of esters, 0.2 to 0.4 part of a purification dispersant, 0.2 to 0.4 part of an antioxidant, 0.04 to 0.06 part of an anti-wear reagent at extreme pressure, 0.02 to 0.04 part of a metal deactivator, 2 to 4 parts of a viscosity index agent, 0.01 to 0.03 part of a de-foaming agent, 0.1 to 0.3 part of a polymethyl methacrylate pour point depressant and 0.01 to 0.03 part of an epoxypropane copolymer de-emulsifier. The long-life energy-saving hydraulic oil disclosed by the invention is excellent in compatibility, energy-saving and environment-friendly, has self-cleaning capability, and is long in service life.

Description

Technical Field

[0001] The present application relates to the technical field of hydraulic system media, and more specifically, to a long-life energy-saving hydraulic oil and a preparation method thereof. Background Art

[0002] The hydraulic system is a transmission system that uses the pressure energy of hydraulic oil to transmit power and control. It transmits the pressure applied to the closed liquid to the part where the liquid is located. The hydraulic system has the advantages of high power density, fast response and easy control, so it is widely used in mechanical equipment such as automobiles, aircraft, and industrial machinery.

[0003] However, with the continuous improvement of China's manufacturing industry, higher requirements have been formed for hydraulic systems, such as high pressure, high efficiency, high precision, large flow, miniaturization, lightweight, integration, environmental protection and energy saving; at the same time, in order to cope with the changing and complex working environment, higher requirements have been put forward for the comprehensive performance of hydraulic oil, such as compatibility, viscosity performance, high temperature cleanliness, oxidation durability, and service life. Summary of the invention

[0004] In order to improve the defects of conventional hydraulic oil such as insufficient compatibility, poor energy-saving and environmental protection performance, weak self-cleaning ability and short service life, the present application provides a long-life energy-saving hydraulic oil and a preparation method thereof.

[0005] In the first aspect, the present application provides a long-life energy-saving hydraulic oil, which adopts the following technical solution:

[0006] A long-life energy-saving hydraulic oil comprises the following raw materials in parts by weight: 90-95 parts of API II base oil, 2-4 parts of esters, 0.2-0.4 parts of detergent dispersant, 0.2-0.4 parts of antioxidant, 0.04-0.06 parts of extreme pressure anti-wear agent, 0.02-0.04 parts of metal deactivator, 2-4 parts of viscosity index agent, 0.01-0.03 parts of defoaming agent, 0.1-0.3 parts of polymethyl methacrylate pour point depressant and 0.01-0.03 parts of propylene oxide copolymer demulsifier.

[0007] Preferably, the detergent dispersant is one of high base petroleum calcium sulfonate, polyisobutylene succinimide, petroleum calcium sulfonate, succinimide and succinate.

[0008] Preferably, the antioxidant is one or more of alkyl diphenylamine, β-(3',5'-di-tert-butyl-4-hydroxyphenyl) propionate, 2,6-di-tert-butyl-p-cresol, phenol ester antioxidant and alkyl phenyl propionate.

[0009] Preferably, the extreme pressure anti-wear agent is one of dialkyl zinc dithiophosphate, dialkyl zinc dithiophosphate, alkyl phosphite, phosphate, ammonium thiophosphate, borate and sulfonate.

[0010] Preferably, the metal deactivator is one of methylbenzotriazole derivatives, phosphates, imidazole derivatives, sulfonates, carboxylic acid derivatives and carboxylate derivatives.

[0011] Preferably, the viscosity modifier is one of polymethyl methacrylate, polyisobutylene and ethylene-propylene copolymer.

[0012] Preferably, the defoamer is one of a polyether organic defoamer, a polysiloxane defoamer, an acrylate copolymer, a methacrylate copolymer, a polyethylene glycol ether, a polybutylene glycol ether, a fatty alcohol, an alkyl phosphate and a composite defoamer.

[0013] Preferably, the long-life energy-saving hydraulic oil comprises the following raw materials in parts by weight: 90-95 parts of API II base oil, 2-4 parts of esters - dioctyl sebacate, 0.2-0.4 parts of detergent dispersant - high base number petroleum calcium sulfonate, 0.2-0.4 parts of antioxidant - alkyl diphenylamine, 0.04-0.06 parts of extreme pressure and anti-wear agent - zinc dialkyl dithiophosphate, 0.02-0.04 parts of metal deactivator - methylbenzotriazole, 2-4 parts of viscosity agent - polymethyl methacrylate, 0.01-0.03 parts of defoaming agent - polyether silicone defoaming agent, 0.1-0.3 parts of polymethyl methacrylate pour point depressant and 0.01-0.03 parts of propylene oxide copolymer demulsifier.

[0014] The long-life energy-saving hydraulic oil of the present application adopts various components with high matching degree, improves the technical defect of unstable base oil quality, prolongs TOST oxidation time, and takes into account the anti-emulsification performance, hydrolysis stability, storage stability, oxidation resistance and compatibility of the oil product, while obtaining a longer thermal stability time, and the oil sample remains clear after the test, with excellent sediment control performance.

[0015] In addition, the long-life energy-saving hydraulic oil of the present application effectively disperses metal chips and sludge deposits in the hydraulic oil by adding nano-scale detergents, and the oil is easy to filter, avoiding the formation of paint film, while achieving better oil cleanliness and hydraulic system cleanliness.

[0016] In addition, the long-life energy-saving hydraulic oil of the present application adopts a straight-chain polymer viscosity index improver, which improves the defect of unstable oil viscosity, extends the oil use cycle, and at the same time obtains better anti-wear performance and anti-corrosion and anti-rust performance.

[0017] Preferably, the long-life energy-saving hydraulic oil further comprises 2-4 parts of a flame retardant, and the flame retardant is a nitrogen-silicon hybrid phosphate flame retardant.

[0018] Preferably, the flame retardant is prepared by combining heptaphenylsilanetriol silsileoxane, diphenyl chlorophosphate and hexachlorocyclotriphosphazene.

[0019] When large hydraulic equipment such as excavators are in use, they are usually close to fire sources, and the presence of hydraulic oil may have a flame retardant effect on fire. The use of flame retardants can not only prevent the spread of fire, but can even suppress the occurrence of fire.

[0020] In the present application, a nitrogen-silicon hybrid phosphate flame retardant is selected, which contains three flame retardant elements: nitrogen, silicon and phosphorus. Specifically, heptaphenylsilanetriol siloxane, diphenyl chlorophosphate and hexachlorocyclotriphosphazene are selected. Among them, hexachlorocyclotriphosphazene is composed of alternating phosphorus nuclei and nitrogen atoms. This conjugated structure enables hexachlorocyclotriphosphazene to have extremely excellent thermal stability.

[0021] During combustion, phosphazene polymers undergo thermal decomposition, which is an endothermic reaction. Phosphates, metaphosphates, and polyphosphates produced during the thermal decomposition process will form a non-volatile protective film to isolate the air. Phosphazene polymers can also produce non-flammable ammonia, including NH3, N2, and NO. X , these gases can dilute the concentration of combustible gases produced during the combustion process.

[0022] In addition, the chlorine atom adjacent to the phosphorus atom in hexachlorocyclotriphosphazene is highly active. Therefore, when heptaphenylsilanetriol siloxane is used in combination with hexachlorocyclotriphosphazene, the chloride ions on the hexachlorocyclotriphosphazene will undergo a substitution reaction with the hydroxyl groups on the heptaphenylsilanetriol siloxane, thereby connecting the heptaphenylsilanetriol siloxane with the hexachlorocyclotriphosphazene.

[0023] Heptaphenylsilanetriol siloxane is a type of polysiloxane flame retardant. Its flame retardant mechanism is that it forms an inorganic oxygen-isolating and heat-insulating protective layer containing Si-O bonds or Si-C bonds characteristic of polysiloxane during combustion. Therefore, when heptaphenylsilanetriol siloxane is used in combination with hexachlorocyclotriphosphazene, a synergistic flame retardant effect of nitrogen, phosphorus and silicon will be obtained, thereby obtaining better flame retardant properties.

[0024] Although the product of heptaphenylsilane triol siloxane and hexachlorocyclotriphosphazene contains a silicon-oxygen bond, its compatibility in hydraulic oil is still relatively poor. In order to further improve the compatibility of the flame retardant in hydraulic oil, the applicant considers using esters as the matrix of the flame retardant, and further selects diphenyl chlorophosphate, so that the chlorine atoms on diphenyl chlorophosphate can also undergo a substitution reaction with the hydroxyl groups on heptaphenylsilane triol siloxane, thereby connecting heptaphenylsilane triol siloxane, hexachlorocyclotriphosphazene and diphenyl chlorophosphate. In addition, in order to avoid the influence of the excess chlorine atoms on the hexachlorocyclotriphosphazene, the applicant uses hydroxyethyl methacrylate to replace the chlorine atoms to obtain a relatively better flame retardant effect.

[0025] Preferably, the preparation method of the flame retardant is: first, heptaphenylsilanetriol siloxane is condensed with diphenyl chlorophosphate to obtain heptaphenyl alcohol-diphenyl phosphate polyhedral oligomeric siloxane; then, heptaphenyl alcohol-diphenyl phosphate polyhedral oligomeric siloxane is condensed with hexachlorocyclotriphosphazene to obtain heptaphenyl cyclotriphosphazene-diphenyl phosphate polyhedral oligomeric siloxane, and finally, hydroxyethyl methacrylate is added until the chloride ions are removed to obtain the flame retardant.

[0026] Preferably, the preparation method of heptaphenyl alcohol-diphenyl phosphate polyhedral oligomeric silsileoxane is:

[0027] First, heptaphenylsilanetriol siloxane and diphenyl chlorophosphate are added to excess anhydrous tetrahydrofuran in a molar ratio of 1: (1.5-2.5), and then the mixture is stirred and heated to reflux, the heating temperature is 40-60° C., the reflux time is 6-10 hours, and finally, it is filtered, the solvent is removed by vacuum distillation, and the mixture is washed and dried to obtain heptaphenyl alcohol-diphenyl phosphate polyhedral oligomeric siloxane.

[0028] Preferably, the method for preparing the flame retardant comprises the following steps:

[0029] Firstly, heptaphenyl alcohol-diphenyl phosphate polyhedral oligomeric semisiloxane and hexachlorocyclotriphosphazene are added to excess anhydrous tetrahydrofuran in a molar ratio of 1:(0.5-1.5), and then the mixture is stirred and heated to reflux, the heating temperature is 60-70°C, and the reflux time is 10-16h, and then hydroxyethyl methacrylate is added until the chloride ions are removed, and finally the mixture is filtered, the solvent is removed by vacuum distillation, and the mixture is washed and dried to obtain a flame retardant.

[0030] In a second aspect, the present application provides a method for preparing a long-life energy-saving hydraulic oil, using the following technical solution:

[0031] A method for preparing a long-life energy-saving hydraulic oil comprises the following steps:

[0032] Step 1: Mix API Class II base oil and ester in proportion for 2-4 hours to form a base mixed oil for standby use;

[0033] Step 2: Raise the temperature of the base mixed liquid to 70-80°C, then add detergent dispersant, antioxidant, extreme pressure wear agent, metal deactivator, viscosity agent, polymethyl methacrylate pour point depressant and propylene oxide copolymer demulsifier in sequence, continue stirring for 2-3 hours until all components are evenly mixed, finally cool to room temperature and add defoamer, continue stirring for 1-2 hours to obtain long-life energy-saving hydraulic oil.

[0034] In summary, this application has the following beneficial effects:

[0035] 1. The long-life energy-saving hydraulic oil of the present application adopts various components with high matching degree, improves the technical defect of unstable base oil quality, prolongs TOST oxidation time, and takes into account the anti-emulsification performance, hydrolysis stability, storage stability, oxidation resistance and compatibility of the oil product, while obtaining a longer thermal stability time. Moreover, the oil sample remains clear after the test and has excellent sediment control performance.

[0036] 2. The long-life energy-saving hydraulic oil of the present application effectively disperses metal chips and sludge deposits in the hydraulic oil by adding nano-scale detergents, and the oil is easy to filter, thus avoiding the formation of paint film, while achieving better oil cleanliness and hydraulic system cleanliness.

[0037] 3. The long-life energy-saving hydraulic oil of the present application adopts a straight-chain polymer viscosity index improver, which improves the defect of unstable oil viscosity, prolongs the oil use cycle, and at the same time obtains better anti-wear performance and anti-corrosion and anti-rust performance.

[0038] 4. Heptaphenylsilanetriol siloxane is a type of polysiloxane flame retardant. Its flame retardant mechanism is that it forms an inorganic oxygen-isolating and heat-insulating protective layer containing Si-O bonds or Si-C bonds characteristic of polysiloxane during combustion. Therefore, when heptaphenylsilanetriol siloxane is used in combination with hexachlorocyclotriphosphazene, a synergistic flame retardant effect of nitrogen, phosphorus and silicon will be obtained, thereby obtaining better flame retardant properties. DETAILED DESCRIPTION

[0039] The present application is further described in detail below in conjunction with Example 1 and Example 6.

[0040] raw material

[0041] API II base oil Jinan Xinhuihuang Chemical; Dioctyl sebacate CAS: 2432-87-3; High base number calcium petroleum sulfonate TBN300; Alkyl diphenylamine T534; Dialkyl dithiophosphate zinc CAS: 68649-42-3; Polymethyl methacrylate CAS: 9011-14-7; Toluene triazole CAS: 13351-73-0; Polyether silicone defoamer DB-518; Polymethyl methacrylate pour point depressant Shijiazhuang Donghang Lubricant Additive Additives; Propylene oxide copolymer demulsifier RO-06; Heptaphenylsilanetriol siloxane CAS: 444315-26-8; Diphenyl chlorophosphate CAS: 2524-64-3; Hexachlorocyclotriphosphazene CAS: 940-71-6; Hydroxyethyl methacrylate CAS: 97-63-2; Tetrahydrofuran CAS: 109-99-9; β-(3',5'-di-tert-butyl-4-hydroxyphenyl) propionate CAS: 125643-61-0.

[0042] Example 1

[0043] A long-life energy-saving hydraulic oil comprises the following raw materials: 93g of API II base oil, 3g of ester-dioctyl sebacate, 0.3g of detergent dispersant-high base number calcium petroleum sulfonate, 0.3g of antioxidant-alkyl diphenylamine, 0.2g of antioxidant-β-(3',5'-di-tert-butyl-4-hydroxyphenyl) propionate, 0.05g of extreme pressure and anti-wear agent-zinc dialkyl dithiophosphate, 0.03g of metal deactivator-methylbenzotriazole, 3g of viscosity agent-polymethyl methacrylate, 0.02g of defoaming agent-polyether silicone defoaming agent, 0.2g of polymethyl methacrylate pour point depressant and 0.02g of propylene oxide copolymer demulsifier.

[0044] The preparation method of long-life energy-saving hydraulic oil comprises the following steps:

[0045] Step 1: Mix API Class II base oil and esters in proportion and stir for 3 hours to form a base mixed oil for standby use;

[0046] Step 2: Raise the temperature of the base mixed liquid to 75°C, then add detergent dispersant, antioxidant, extreme pressure wear agent, metal deactivator, viscosity agent, polymethyl methacrylate pour point depressant and propylene oxide copolymer demulsifier in sequence, continue stirring for 3 hours until all components are evenly mixed, finally cool to room temperature and add defoamer, continue stirring for 2 hours to obtain long-life energy-saving hydraulic oil.

[0047] It should be noted that in the present application, the detergent dispersant may be selected from one of high base value petroleum calcium sulfonate, polyisobutylene succinimide, petroleum calcium sulfonate, succinimide and succinate;

[0048] The antioxidant may be selected from one of alkyl diphenylamine, 2,6-di-tert-butyl-p-cresol, phenol ester antioxidant and alkyl phenyl propionate;

[0049] The extreme pressure anti-wear agent can be selected from one of dialkyl zinc dithiophosphate, dialkyl zinc dithiophosphate, alkyl phosphite, phosphate, ammonium thiophosphate, borate and sulfonate;

[0050] The metal deactivator can be selected from one of methylbenzotriazole derivatives, phosphates, imidazole derivatives, sulfonates, carboxylic acid derivatives and carboxylic acid ester derivatives;

[0051] The viscosity modifier can be selected from one of polymethyl methacrylate, polyisobutylene and ethylene-propylene copolymer.

[0052] The defoamer can be selected from one of polyether organic defoamers, polysiloxane defoamers, acrylate copolymers, methacrylate copolymers, polyethylene glycol ethers, polybutylene glycol ethers, fatty alcohols, alkyl phosphates and composite defoamers;

[0053] Among them, the long-life energy-saving hydraulic oil obtained by the various component options of this embodiment 1 has relatively better comprehensive performance, and its specific performance data are shown in Table 1.

[0054] Table 1 Performance data of Example 1

[0055]

[0056]

[0057] Example 2

[0058] The difference from Example 1 is that 3 g of flame retardant is further added to the long-life energy-saving hydraulic oil, and the flame retardant is hexachlorocyclotriphosphazene.

[0059] Example 3

[0060] The difference from Example 2 is that the flame retardant is a complex of hexachlorocyclotriphosphazene and heptaphenylsilanetriol silsilesemioxane;

[0061] The preparation method of the complex of hexachlorocyclotriphosphazene and heptaphenylsilanetriol semisiloxane is as follows:

[0062] Firstly, heptaphenylsilanetriol siloxane and hexachlorocyclotriphosphazene are added to excess anhydrous tetrahydrofuran in a molar ratio of 1:3, and then the mixture is stirred and heated to reflux at a heating temperature of 50°C and a reflux time of 8 hours. Finally, the mixture is filtered, the solvent is removed by vacuum distillation, and the mixture is washed and dried to obtain a complex of hexachlorocyclotriphosphazene and heptaphenylsilanetriol siloxane.

[0063] Example 4

[0064] The difference from Example 2 is that the flame retardant is a complex of heptaphenylsilanetriol silsileoxane, diphenyl chlorophosphate and hexachlorocyclotriphosphazene;

[0065] The preparation method of the flame retardant comprises the following steps:

[0066] Preparation of heptaphenyl alcohol-diphenyl phosphate polyhedral oligomeric silsileoxane:

[0067] Firstly, heptaphenylsilanetriol silsileoxane and diphenyl chlorophosphate were added to excess anhydrous tetrahydrofuran in a molar ratio of 1:2, and then the mixture was stirred and heated to reflux at a heating temperature of 50°C for 8 hours, and finally filtered, the solvent was removed by vacuum distillation, and the mixture was washed and dried to obtain heptaphenyl alcohol-diphenyl phosphate polyhedral oligomeric silsileoxane;

[0068] Preparation of flame retardant: First, add heptaphenyl alcohol-diphenyl phosphate polyhedral oligomeric semisiloxane and hexachlorocyclotriphosphazene in a molar ratio of 1:1 to excess anhydrous tetrahydrofuran, then stir and heat the mixture to reflux, the heating temperature is 65°C, the reflux time is 14 hours, and then hydroxyethyl methacrylate is added until the chloride ions are removed, finally filter, remove the solvent by reduced pressure distillation, wash and dry to obtain a flame retardant.

[0069] Example 5-Example 6

[0070] The difference from Example 4 is that the molar ratios of heptaphenylsilanetriol silsileoxane, diphenyl chlorophosphate and hexachlorocyclotriphosphazene are different, as shown in Table 2.

[0071] Table 2 Molar ratio of each component of flame retardant in Example 4-Example 6

[0072] Example 4 Example 5 Example 6 Heptaphenylsilanetriol silsilexanes 1 1 1 Diphenyl chlorophosphate 2 1.5 2.5 Hexachlorocyclotriphosphazene 1 1.5 0.5

[0073] The flame retardancy of Examples 1 to 6 was tested with reference to MIL-PRF-87257B. The test data are shown in Table 3.

[0074] Table 3 Flame retardant performance data of Example 1 to Example 6

[0075] Flame propagation speed (cm / s) Flame propagation speed (cm / s) Example 1 0.49 Example 4 0.27 Example 2 0.36 Example 5 0.28 Example 3 0.29 Example 6 0.28

[0076] With reference to Example 1 and in combination with Table 1, it can be seen that the long-life energy-saving hydraulic oil of the present application adopts highly matched extreme pressure anti-wear agents, antioxidants, defoaming agents, and viscosity index agents, which improves the technical defects of unstable base oil quality, is conducive to extending the TOST oxidation time to more than 8000 hours, and takes into account the anti-emulsification performance, hydrolysis stability, storage stability, antioxidant and compatibility of the oil.

[0077] Referring to Example 1 and Example 2 and combining with Table 3, it can be seen that the flame propagation speed of Example 2 is significantly slowed down compared with Example 1, which shows that the addition of hexachlorocyclotriphosphazene can significantly improve the flame retardant properties of the long-life energy-saving hydraulic oil.

[0078] The reason is that hexachlorocyclotriphosphazene is composed of alternating phosphorus atoms and nitrogen atoms. This conjugated structure makes hexachlorocyclotriphosphazene have extremely good thermal stability.

[0079] During combustion, phosphazene polymers undergo thermal decomposition, which is an endothermic reaction. Phosphates, metaphosphates, and polyphosphates produced during the thermal decomposition process will form a non-volatile protective film to isolate the air. Phosphazene polymers can also produce non-flammable ammonia, including NH3, N2, and NO. X , these gases can dilute the concentration of combustible gases produced during the combustion process.

[0080] Referring to Example 2 and Example 3 and combining with Table 3, it can be seen that the flame propagation speed of Example 3 is further slowed down compared with Example 2, which shows that the addition of heptaphenylsilanetriol semisiloxane can further improve the flame retardant properties of the long-life energy-saving hydraulic oil.

[0081] The reason is that the chlorine atom adjacent to the phosphorus atom in hexachlorocyclotriphosphazene is highly active. Therefore, when heptaphenylsilanetriol siloxane is used in combination with hexachlorocyclotriphosphazene, the chloride ions on the hexachlorocyclotriphosphazene will undergo a substitution reaction with the hydroxyl groups on the heptaphenylsilanetriol siloxane, thereby connecting the heptaphenylsilanetriol siloxane and the hexachlorocyclotriphosphazene.

[0082] Heptaphenylsilanetriol siloxane is a type of polysiloxane flame retardant. Its flame retardant mechanism is that it forms an inorganic oxygen-isolating and heat-insulating protective layer containing Si-O bonds or Si-C bonds characteristic of polysiloxane during combustion. Therefore, when heptaphenylsilanetriol siloxane is used in combination with hexachlorocyclotriphosphazene, a synergistic flame retardant effect of nitrogen, phosphorus and silicon will be obtained, thereby obtaining better flame retardant properties.

[0083] Referring to Example 3 and Example 4 and in combination with Table 3, it can be seen that, relative to Example 3, the flame propagation speed of Example 4 is further slowed down, which indicates that the addition of diphenyl chlorophosphate can further improve the flame retardant properties of the long-life energy-saving hydraulic oil.

[0084] The reason is that, although the product of heptaphenylsilane triol siloxane and hexachlorocyclotriphosphazene contains a silicon-oxygen bond, its compatibility in hydraulic oil is still relatively poor. In order to further improve the compatibility of the flame retardant in hydraulic oil, the applicant considers using esters as the matrix of the flame retardant, and further selects diphenyl chlorophosphate, so that the chlorine atoms on diphenyl chlorophosphate can also undergo a substitution reaction with the hydroxyl groups on heptaphenylsilane triol siloxane, thereby connecting heptaphenylsilane triol siloxane, hexachlorocyclotriphosphazene and diphenyl chlorophosphate. In addition, in order to avoid the influence of the excess chlorine atoms on the hexachlorocyclotriphosphazene, the applicant uses hydroxyethyl methacrylate to replace the chlorine atoms to obtain a relatively better flame retardant effect.

[0085] With reference to Examples 4 to 6 and in combination with Table 3, it can be seen that, relative to Example 4, the flame propagation speeds of Examples 5 to 6 are slightly accelerated, which indicates that when the molar ratio of heptaphenylsilanetriol siloxane, diphenyl chlorophosphate and hexachlorocyclotriphosphazene is the same as that of Example 4, the flame retardant prepared can promote the long-life energy-saving hydraulic oil to have a better anti-flammability effect.

[0086] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A long-life energy-saving hydraulic oil, characterized in that: The invention comprises the following raw materials in parts by weight: 90-95 parts of API II base oil, 2-4 parts of esters, 0.2-0.4 parts of detergent dispersant, 0.2-0.4 parts of antioxidant, 0.04-0.06 parts of extreme pressure anti-wear agent, 0.02-0.04 parts of metal deactivator, 2-4 parts of viscosity index agent, 0.01-0.03 parts of defoaming agent, 0.1-0.3 parts of polymethyl methacrylate pour point depressant and 0.01-0.03 parts of propylene oxide copolymer demulsifier.

2. The long-life energy-saving hydraulic oil according to claim 1, characterized in that: The cleaning dispersant is one of high base petroleum calcium sulfonate, polyisobutylene succinimide, petroleum calcium sulfonate, succinimide and succinate; and / or; The antioxidant is one or more of alkyl diphenylamine, β-(3',5'-di-tert-butyl-4-hydroxyphenyl) propionate, 2,6-di-tert-butyl-p-cresol, phenol ester antioxidant and alkyl phenyl propionate; and / or; The extreme pressure anti-wear agent is one of dialkyl zinc dithiophosphate, dialkyl zinc dithiophosphate, alkyl phosphite, phosphate, thiophosphate ammonium salt, borate and sulfonate; and / or; The metal deactivator is one of a methylbenzotriazole derivative, a phosphate, an imidazole derivative, a sulfonate, a carboxylic acid derivative and a carboxylic acid ester derivative; and / or; The viscosity modifier is one of polymethyl methacrylate, polyisobutylene and ethylene-propylene copolymer; and / or; The defoamer is one of polyether organic defoamer, polysiloxane type defoamer, acrylate copolymer, polyethylene glycol ether, polybutylene glycol ether, fatty alcohol, alkyl phosphate and composite defoamer.

3. The long-life energy-saving hydraulic oil according to claim 2, characterized in that: The long-life energy-saving hydraulic oil comprises the following raw materials in parts by weight: 90-95 parts of API II base oil, 2-4 parts of esters-dioctyl sebacate, 0.2-0.4 parts of detergent dispersant-high base number petroleum calcium sulfonate, 0.2-0.4 parts of antioxidant-alkyl diphenylamine, 0.04-0.06 parts of extreme pressure anti-wear agent-zinc dialkyl dithiophosphate, 0.02-0.04 parts of metal deactivator-methylbenzotriazole, 2-4 parts of viscosity index agent-polymethyl methacrylate, 0.01-0.03 parts of defoaming agent-polyether silicone defoaming agent, 0.1-0.3 parts of polymethyl methacrylate pour point depressant and 0.01-0.03 parts of propylene oxide copolymer demulsifier.

4. The long-life energy-saving hydraulic oil according to claim 3, characterized in that: The long-life energy-saving hydraulic oil also includes 2-4 parts of a flame retardant, and the flame retardant is a nitrogen-silicon hybrid phosphate flame retardant.

5. The long-life energy-saving hydraulic oil according to claim 4, characterized in that: The flame retardant is obtained by the coordinated reaction of heptaphenylsilanetriol siloxane, diphenyl chlorophosphate and hexachlorocyclotriphosphazene.

6. The long-life energy-saving hydraulic oil according to claim 5, characterized in that: The preparation method of the flame retardant is: Firstly, heptaphenylsilanetriol siloxane is condensed with diphenyl chlorophosphate to obtain heptaphenyl alcohol-diphenyl phosphate polyhedral oligomeric siloxane; then, heptaphenyl alcohol-diphenyl phosphate polyhedral oligomeric siloxane is condensed with hexachlorocyclotriphosphazene to obtain heptaphenyl cyclotriphosphazene-diphenyl phosphate polyhedral oligomeric siloxane, and finally hydroxyethyl methacrylate is added until chloride ions are removed to obtain a flame retardant.

7. The long-life energy-saving hydraulic oil according to claim 6, characterized in that: The preparation method of the heptaphenyl alcohol-diphenyl phosphate polyhedral oligomeric silsemioxane is: First, heptaphenylsilanetriol siloxane and diphenyl chlorophosphate are added to excess anhydrous tetrahydrofuran in a molar ratio of 1: (1.5-2.5), and then the mixture is stirred and heated to reflux, the heating temperature is 40-60° C., the reflux time is 6-10 hours, and finally, it is filtered, the solvent is removed by vacuum distillation, and the mixture is washed and dried to obtain heptaphenyl alcohol-diphenyl phosphate polyhedral oligomeric siloxane.

8. The long-life energy-saving hydraulic oil according to claim 7, characterized in that: The preparation method of the flame retardant is: Firstly, heptaphenyl alcohol-diphenyl phosphate polyhedral oligomeric semisiloxane and hexachlorocyclotriphosphazene are added to excess anhydrous tetrahydrofuran in a molar ratio of 1:(0.5-1.5), and then the mixture is stirred and heated to reflux, the heating temperature is 60-70°C, and the reflux time is 10-16h, and then hydroxyethyl methacrylate is added until the chloride ions are removed, and finally the mixture is filtered, the solvent is removed by vacuum distillation, and the mixture is washed and dried to obtain a flame retardant.

9. A method for preparing the long-life energy-saving hydraulic oil according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Mix API Class II base oil and ester in proportion for 2-4 hours to form a base mixed oil for standby use; Step 2: Raise the temperature of the base mixed liquid to 70-80°C, then add detergent dispersant, antioxidant, extreme pressure wear agent, metal deactivator, viscosity agent, polymethyl methacrylate pour point depressant and propylene oxide copolymer demulsifier in sequence, continue stirring for 2-3 hours until all components are evenly mixed, finally cool to room temperature and add defoamer, continue stirring for 1-2 hours to obtain long-life energy-saving hydraulic oil.

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