High temperature resistant grease for gears and preparation method thereof

Abstract

The present application relates to the field of lubricating materials, and specifically discloses a high temperature resistant grease for gears and a preparation method thereof, wherein the grease comprises the following raw materials: synthetic oil PAO, ester base oil, thickener, antioxidant, extreme pressure anti-wear agent, rust inhibitor, Peek-based composite additive; Peek-based composite additive is prepared by mixing polyetheretherketone with hydrogenated styrene isoprene copolymer, impregnating with porous polyester-silicon dioxide composite microspheres, and then drying; its preparation method comprises the following steps: mixing synthetic oil PAO and ester base oil, heating and stirring, heating and stirring after adding antioxidant; cooling, adding extreme pressure anti-wear agent and rust inhibitor, stirring, adding thickener and Peek-based composite additive, mixing and stirring, cooling, and preparing. The present application has the characteristics of improving the dropping point of household appliance gear grease, thereby improving its high temperature resistance, and not softening and flowing out under high temperature working conditions to affect the lubrication effect.

Description

Technical Field

[0001] The present application relates to the field of lubricating materials, and more specifically, to a high temperature resistant lubricating grease for gears and a preparation method thereof. Background Art

[0002] With the rapid development of industrial process, grease is widely used due to its good anti-friction and anti-wear effects, and has become an indispensable lubricant in industrial equipment.

[0003] Grease is made of mineral oil or synthetic lubricating oil and thickener. It is a thick, oily semi-solid and is used in the friction parts of machinery to lubricate, reduce mechanical friction, and prevent mechanical wear. It also has a protective effect against metal corrosion and a sealing and dust-proof effect.

[0004] Gear grease is used in equipment such as reducers, motors, and conveyor belts. Grease is also needed for gear lubrication in common household appliances. However, the current dropping point of grease is limited. Household appliance gears such as dishwasher slides, refrigerator slides, and coffee machine gear sliding parts are exposed to high temperature environments during operation. Grease with a low dropping point tends to soften or even flow away during high-temperature operation, and cannot maintain a stable lubrication layer, causing the gears to lose effective lubrication and increase the risk of gear wear and failure. Grease with a low dropping point tends to oxidize and deteriorate in high-temperature environments, generating harmful substances, which not only affects the lubrication effect, but also causes corrosion on the gear surface, thereby shortening the practical life of the gears and the entire household appliance product.

[0005] Therefore, there is an urgent need to develop a gear grease with a high dropping point and high temperature resistance to ensure that the gears still maintain a stable lubrication effect at high temperatures and reduce the lubrication aging problem caused by high temperatures. Summary of the invention

[0006] In order to increase the dropping point of gear grease and thereby improve its high temperature resistance, the present application provides a high temperature resistant grease for gears and a preparation method thereof.

[0007] In a first aspect, the present application provides a high temperature resistant grease for gears, which adopts the following technical solution:

[0008] A high temperature resistant lubricating grease for gears, comprising the following raw materials in parts by weight:

[0009] 75-90 parts of synthetic oil PAO, 5-10 parts of ester base oil, 10-20 parts of thickener, 0.1-2 parts of antioxidant, 0.2-1 parts of extreme pressure anti-wear agent, 0.1-1 parts of rust inhibitor, 0.5-3 parts of Peek-based composite additives;

[0010] The Peek-based composite additive is prepared by mixing polyetheretherketone with hydrogenated styrene isoprene copolymer, then mixing with porous polyester-silicon dioxide composite microspheres, impregnating under ultrasonic-assisted conditions, and then drying.

[0011] By adopting the above-mentioned technical scheme, a Peek-based composite additive is added to the grease in the present application, so that Peek is added to the grease as a solid lubricant. Peek has excellent thermal stability and high temperature resistance, and can maintain its physical and chemical properties unchanged in a high temperature environment. The addition of Peek in the present application can significantly improve the high temperature resistance of the grease, so that it can still maintain a good lubrication effect under high temperature conditions, and the addition of Peek can increase the consistency and viscosity of the grease, thereby increasing the dropping point of the grease, making the grease not easy to flow at high temperatures and being able to maintain the lubrication effect for a longer time.

[0012] In the present application, polyetheretherketone, hydrogenated styreneisoprene copolymer and porous polyester-silica composite microspheres are mixed and impregnated under ultrasonic-assisted conditions, and polyetheretherketone is loaded on the porous polyester-silica composite microspheres under the bonding effect of hydrogenated styreneisoprene copolymer, thereby realizing the loading of Peek on the porous polyester-silica composite microspheres. Peek is added in the form of being loaded on porous polyester-silica composite microspheres, thereby improving the compatibility of Peek with grease, which is not only conducive to the uniform dispersion of Peek in the grease, but also further improves the high temperature resistance of the grease, and prevents the stability and lubrication effect of the grease from being affected by the poor compatibility of Peek with the grease.

[0013] Optionally, the porous polyester-silicon dioxide composite microspheres are prepared by the following method:

[0014] 1) Mix carboxylic acid monomer and polyol monomer as monomer raw materials, then heat to 170-185°C, then add catalyst and hydrophobic silica, heat to 200-220°C and react at 0.06-0.08MPa pressure for 2-3h to obtain polyester primary product;

[0015] 2) Sodium bicarbonate is mixed with ethyl acetate and dichloromethane to prepare a pore-forming agent, and then the polyester primary product and the pore-forming agent are fully mixed and stirred, and then heated to 90-130° C., and then directly placed in 3-10° C. water, cooled, and cut to obtain porous polyester-silicon dioxide composite microspheres.

[0016] By adopting the above technical scheme, in the present application, carboxylic acid monomers and polyol monomers are converted into oligomers through esterification reaction, and then hydrophobic silica is used as a skeleton to obtain polyester polymers through polycondensation. After the obtained polyester primary product is mixed with ethyl acetate and sodium bicarbonate, the polyester primary product is dissolved in ethyl acetate and dichloromethane organic solvents, and at the same time, sodium bicarbonate is dispersed in the polyester primary product. Then, the temperature is increased to volatilize the solvents ethyl acetate and dichloromethane, and at the same time, sodium bicarbonate is decomposed to form a pore structure in the polyester product. Then, the product is directly and rapidly cooled to further realize the construction and shaping of the pore structure in the polyester product, and porous polyester-carbon dioxide composite microspheres are obtained. The addition of the silica skeleton improves the high temperature resistance of the composite microspheres.

[0017] Optionally, when preparing porous polyester-silica composite microspheres, the mass ratio of the carboxylic acid monomer to the polyol monomer in step 1) is 1:(1.2-1.4), the amount of hydrophobic silica added is 30-40wt% of the monomer raw material, and the amount of catalyst added is 0.3-0.5wt% of the monomer raw material;

[0018] In step 2), the mass ratio of sodium bicarbonate to ethyl acetate and dichloromethane is 1:(8-10):(4-6), and the amount of pore-forming agent added is 3-5wt% of the amount of polyester primary product added.

[0019] By adopting the above technical scheme, a relatively larger amount of polyol monomer is added when preparing polyester products, so that the final polyester product contains a small amount of hydroxyl groups, and the hydroxyl groups on the polyester product can form chemical bonds with polyetheretherketone. When preparing Peek-based composite additives, the porous polyester-silica composite microspheres have a better chemical bonding effect on the polyetheretherketone precursor. Finally, the more firmly the polyetheretherketone is loaded on the porous polyester-silica composite microspheres, the more conducive it is to improving the compatibility of Peek in the grease, improving the uniform dispersion, and thus improving the high temperature resistance of the grease.

[0020] Optionally, the carboxylic acid monomer is selected from one or more of terephthalic acid, dimethyl terephthalate and isophthalic acid, and the polyol monomer is selected from one or more of ethylene glycol, propylene glycol and 1,4-butanediol;

[0021] The hydrophobic silica is silica R972, and the catalyst is a mixture of p-toluenesulfonic acid and titanate catalyst.

[0022] More preferably, the carboxylic acid monomer comprises at least dimethyl terephthalate, the polyol comprises at least 1,4-butanediol, and the catalyst is a mixture of p-toluenesulfonic acid and a titanate catalyst in a mass ratio of 1:(2-3).

[0023] Optionally, the Peek-based composite additive is prepared by the following method:

[0024] The hydrogenated styrene isoprene copolymer and ethyl acetate are mixed in a mass ratio of 1: (0.2-0.3), and then polyetheretherketone is added and mixed, and then porous polyester-silica composite microspheres are added, stirred and immersed for 20-30 minutes under ultrasonic conditions, and then dried at 80-90° C. to obtain a Peek-based composite additive, wherein the added mass ratio of polyetheretherketone to the hydrogenated styrene isoprene copolymer is 1: (0.2-0.3), and the added mass ratio of porous polyester-silica composite microspheres to polyetheretherketone is 1: (2-3).

[0025] By adopting the above technical scheme, the hydrogenated styrene isoprene copolymer is first dissolved in ethyl acetate and diluted to a certain extent to become a fluid, and then mixed with polyetheretherketone, which is beneficial to the dispersion of polyetheretherketone in the hydrogenated styrene isoprene copolymer. After mixing, porous polyester-silica composite microspheres are added, and polyetheretherketone is bonded to the porous polyester-silica composite microspheres through the hydrogenated styrene isoprene copolymer under ultrasonic conditions. Then, it is dried at 80-90°C to remove the ethyl acetate solvent, and the polyetheretherketone is solidified on the composite microspheres to achieve the loading of polyetheretherketone on the porous polyester-silica composite microspheres.

[0026] Optionally, the thickener is silicon dioxide R972;

[0027] The antioxidant is selected from one or more of amine antioxidants and phenolic antioxidants;

[0028] The extreme pressure anti-wear agent is a phosphate extreme pressure anti-wear agent;

[0029] The rust inhibitor is an amine rust inhibitor.

[0030] Optionally, the synthetic oil PAO is selected from PAO40 and PAO10 in a mass ratio of 1:(1.8-2.2);

[0031] The antioxidant is a mixture of an amine antioxidant and a phenolic antioxidant in a mass ratio of 1:(0.8-1.2);

[0032] The extreme pressure anti-wear agent is triphenylthiophosphate;

[0033] The rust inhibitor is ammonium phosphate mixed solution 349.

[0034] In a second aspect, the present application provides a method for preparing a high temperature resistant grease for gears, using the following technical solution:

[0035] A method for preparing high temperature resistant lubricating grease for gears, comprising the following steps:

[0036] S1. Mix the synthetic oil PAO and the ester base oil, heat to 45-60°C, stir for 30-40 minutes, then add the antioxidant and heat to 70-80°C, stir for 15-25 minutes;

[0037] S2. Cool to 50-60°C and then add extreme pressure anti-wear agent and rust inhibitor, stir for 10-20 minutes, then add thickener and Peek-based composite additive, mix and stir for 20-40 minutes, cool, and obtain high temperature resistant grease for gears.

[0038] By adopting the above technical solution, the preparation method of the present application is simple and convenient and easy to realize industrialization.

[0039] In summary, this application has the following beneficial effects:

[0040] 1. In the present application, a Peek-based composite additive is added to the grease, so that Peek is added to the grease as a solid lubricant. Peek has excellent thermal stability and high temperature resistance, and can maintain its physical and chemical properties unchanged in a high temperature environment. The addition of Peek in the present application can significantly improve the high temperature resistance of the grease, so that it can still maintain a good lubrication effect under high temperature conditions, and the addition of Peek can increase the consistency and viscosity of the grease, thereby increasing the dropping point of the grease, making the grease difficult to flow at high temperatures and able to maintain a longer lubrication effect;

[0041] 2. In the present application, polyetheretherketone, hydrogenated styreneisoprene copolymer and porous polyester-silica composite microspheres are mixed and impregnated under ultrasonic-assisted conditions. Under the bonding effect of the hydrogenated styreneisoprene copolymer, the polyetheretherketone is loaded on the porous polyester-silica composite microspheres, thereby improving the compatibility of Peek with the grease. This is not only beneficial to the uniform dispersion of Peek in the grease, further improving the high temperature resistance of the grease, but also preventing the stability and lubrication effect of the grease from being affected by the poor compatibility of Peek with the grease. DETAILED DESCRIPTION

[0042] The present application is further described in detail below in conjunction with the examples. It is particularly noted that if no specific conditions are specified in the following examples, the experiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0043] In the following preparation examples and examples, the hydrogenated styrene isoprene copolymer is purchased from Wuhan Huaxiang Kejie Biotechnology Co., Ltd., with a CAS number of 68648-89-5;

[0044] The titanate catalyst used was isopropyl titanate produced by Jinan Mingxin Chemical Co., Ltd.

[0045] The following preparation example is an example of the preparation of porous polyester-silica composite microspheres

[0046] Preparation Example 1

[0047] A method for preparing porous polyester-silicon dioxide composite microspheres comprises the following steps:

[0048] 1) A mixture of dimethyl terephthalate and terephthalic acid in a mass ratio of 1:0.8 is used as a carboxylic acid monomer, and a mixture of ethylene glycol and 1,4-butanediol in a mass ratio of 1:2 is used as a polyol monomer;

[0049] The carboxylic acid monomer and the polyol monomer are mixed in a mass ratio of 1:1.3 as monomer raw materials, and then the temperature is raised to 180°C, and then a catalyst and silica R972 are added, and the temperature is raised to 210°C and reacted at a pressure of 0.07MPa for 2-3h to obtain a polyester primary product;

[0050] 2) Sodium bicarbonate, ethyl acetate and dichloromethane were mixed in a mass ratio of 1:9:5 to prepare a pore-forming agent, and then the polyester primary product and the pore-forming agent were fully mixed and stirred, and then heated to 120°C, reacted for 30 minutes, and then directly placed in 5°C water for cooling, and then cut to obtain porous polyester-silica composite microspheres.

[0051] Wherein, in step 1), the catalyst is a mixture of p-toluenesulfonic acid and titanate catalyst in a mass ratio of 1:2.5, the amount of hydrophobic silica added is 35wt% of the monomer raw material, and the amount of catalyst added is 0.4wt% of the monomer raw material;

[0052] The amount of the pore-forming agent added in step 2) is 4 wt% of the amount of the polyester primary product added.

[0053] Preparation Example 2

[0054] A method for preparing porous polyester-silicon dioxide composite microspheres comprises the following steps:

[0055] 1) A mixture of dimethyl terephthalate and terephthalic acid in a mass ratio of 1:0.8 is used as a carboxylic acid monomer, and a mixture of ethylene glycol and 1,4-butanediol in a mass ratio of 1:2 is used as a polyol monomer;

[0056] The carboxylic acid monomer and the polyol monomer are mixed in a mass ratio of 1:1.2 as monomer raw materials, and then the temperature is raised to 170°C, and then a catalyst and silica R972 are added, and the temperature is raised to 200°C and reacted at a pressure of 0.06MPa for 3h to obtain a polyester primary product;

[0057] 2) Sodium bicarbonate, ethyl acetate and dichloromethane were mixed in a mass ratio of 1:8:4 to prepare a pore-forming agent, and then the polyester primary product and the pore-forming agent were fully mixed and stirred, and then heated to 90°C, reacted for 40 minutes, and then directly placed in 3°C water for cooling, and then cut to obtain porous polyester-silica composite microspheres.

[0058] Wherein, in step 1), the catalyst is a mixture of p-toluenesulfonic acid and titanate catalyst in a mass ratio of 1:2, the amount of hydrophobic silica added is 30wt% of the monomer raw material, and the amount of catalyst added is 0.3wt% of the monomer raw material;

[0059] The amount of the pore-forming agent added in step 2) is 3 wt% of the amount of the polyester primary product added.

[0060] Preparation Example 3

[0061] A method for preparing porous polyester-silicon dioxide composite microspheres comprises the following steps:

[0062] 1) A mixture of dimethyl terephthalate and terephthalic acid in a mass ratio of 1:0.8 is used as a carboxylic acid monomer, and a mixture of ethylene glycol and 1,4-butanediol in a mass ratio of 1:2 is used as a polyol monomer;

[0063] The carboxylic acid monomer and the polyol monomer were mixed in a mass ratio of 1:1.4 as monomer raw materials, and then the temperature was raised to 185°C, and then a catalyst and silica R972 were added, and the temperature was raised to 220°C and reacted at a pressure of 0.08 MPa for 2 hours to obtain a polyester primary product;

[0064] 2) Sodium bicarbonate, ethyl acetate and dichloromethane were mixed in a mass ratio of 1:10:6 to prepare a pore-forming agent, and then the polyester primary product and the pore-forming agent were fully mixed and stirred, and then heated to 130°C, reacted for 20 minutes, and then directly placed in 10°C water for cooling, and then cut to obtain porous polyester-silica composite microspheres.

[0065] Wherein, in step 1), the catalyst is a mixture of p-toluenesulfonic acid and titanate catalyst in a mass ratio of 1:3, the amount of hydrophobic silica added is 40wt% of the monomer raw material, and the amount of catalyst added is 0.5wt% of the monomer raw material;

[0066] The amount of the pore-forming agent added in step 2) is 5 wt% of the amount of the polyester primary product added.

[0067] Preparation Example 4

[0068] A method for preparing porous polyester-silica composite microspheres is carried out according to the method in Preparation Example 1, except that in step 1), the carboxylic acid monomers are terephthalic acid and isophthalic acid in a mass ratio of 1:1.

[0069] Preparation Example 5

[0070] A method for preparing porous polyester-silica composite microspheres is carried out according to the method in Preparation Example 1, except that no pore-forming agent is added in step 2), and the polyester product after the reaction in step 1) is directly placed in 5° C. water for cooling, and then cut to obtain porous polyester-silica composite microspheres.

[0071] Preparation Example 6

[0072] A method for preparing porous polyester-silica composite microspheres is carried out according to the method in Preparation Example 1, except that in step 2), the polyester primary product is mixed with a pore-forming agent and then heated to 120° C., reacted for 30 minutes, naturally cooled to room temperature, and cut to obtain porous polyester-silica composite microspheres.

[0073] Comparative Preparation Example 1

[0074] A method for preparing porous polyester-silica composite microspheres is carried out according to the method in Preparation Example 1, except that hydrophobic silica is not added in step 1).

[0075] Example 1

[0076] A method for preparing high temperature resistant lubricating grease for gears, comprising the following steps:

[0077] S1, 80 kg of synthetic oil PAO and 8 kg of ester base oil were mixed, the temperature was raised to 50° C., and stirred for 35 min. Then, 1 kg of antioxidant was added, the temperature was raised to 75° C., and stirred for 20 min to obtain a mixture A;

[0078] The synthetic oil PAO is a polyalphaolefin synthetic oil PAO40 and a polyalphaolefin synthetic oil PAO10 with a mass ratio of 1:2, the ester base oil is a polyol ester 3970 (specifically, CRODA saturated polyol ester Priolube 3970), and the antioxidant is a mixture of an amine antioxidant L57 and a phenolic antioxidant L115 with a mass ratio of 1:1;

[0079] S2, cooling the mixture A in step S1 to 55° C., then adding 0.5 kg of extreme pressure anti-wear agent triphenylthiophosphate TPPT and 0.5 kg of rust inhibitor phosphate amine mixed solution 349, stirring for 15 min, then adding 15 kg of thickener silicon dioxide R972 and 1.8 kg of Peek-based composite additives, mixing and stirring for 30 min, cooling, and obtaining a high temperature resistant grease for gears;

[0080] Wherein, the Peek-based composite additive in step S2 is prepared by the following method:

[0081] The hydrogenated styrene isoprene copolymer and ethyl acetate were mixed in a mass ratio of 1:0.2, and then polyetheretherketone Peek was added and mixed, and then the porous polyester-silica composite microspheres prepared in Preparation Example 1 were added, and after stirring, the mixture was immersed in an ultrasonic condition (ultrasonic power 40w) for 20-30min, and then dried at 85°C to obtain a Peek-based composite additive, wherein the added mass ratio of polyetheretherketone to hydrogenated styrene isoprene copolymer was 1:0.3, and the added mass ratio of porous polyester-silica composite microspheres to polyetheretherketone was 1:2.

[0082] Example 2

[0083] A method for preparing high temperature resistant lubricating grease for gears, comprising the following steps:

[0084] S1, 75 kg of synthetic oil PAO and 5 kg of ester base oil were mixed, the temperature was raised to 45° C., and stirred for 40 min, then 0.1 kg of antioxidant was added, the temperature was raised to 70° C., and stirred for 25 min to obtain mixture A;

[0085] The synthetic oil PAO is a polyalphaolefin synthetic oil PAO40 and a polyalphaolefin synthetic oil PAO10 with a mass ratio of 1:1.8, the ester base oil is a polyol ester 3970 (specifically, CRODA saturated polyol ester Priolube 3970), and the antioxidant is a mixture of an amine antioxidant L57 and a phenolic antioxidant L115 with a mass ratio of 1:0.8;

[0086] S2, cooling the mixture A in step S1 to 50°C, then adding 0.2kg of extreme pressure anti-wear agent triphenylthiophosphate TPPT and 0.1kg of rust inhibitor phosphate amine mixed solution 349, stirring for 20min, then adding 10kg of thickener silicon dioxide R972 and 0.5kg of Peek-based composite additive, mixing and stirring for 20min, cooling, and obtaining high temperature resistant grease for gears;

[0087] Wherein, the Peek-based composite additive in step S2 is prepared by the following method:

[0088] The hydrogenated styrene isoprene copolymer and ethyl acetate were mixed in a mass ratio of 1:0.2, and then polyetheretherketone Peek was added and mixed, and then the porous polyester-silica composite microspheres prepared in Preparation Example 2 were added, and after stirring, the mixture was immersed in an ultrasonic condition (ultrasonic power 40w) for 20 minutes, and then dried at 80°C to obtain a Peek-based composite additive, wherein the added mass ratio of polyetheretherketone to hydrogenated styrene isoprene copolymer was 1:0.2, and the added mass ratio of porous polyester-silica composite microspheres to polyetheretherketone was 1:2.

[0089] Example 3

[0090] A method for preparing high temperature resistant lubricating grease for gears, comprising the following steps:

[0091] S1, 90 kg of synthetic oil PAO and 10 kg of ester base oil were mixed, the temperature was raised to 60° C., and stirred for 30 min, then 2 kg of antioxidant was added, the temperature was raised to 80° C., and stirred for 15 min to obtain mixture A;

[0092] The synthetic oil PAO is a polyalphaolefin synthetic oil PAO40 and a polyalphaolefin synthetic oil PAO10 with a mass ratio of 1:2.2, the ester base oil is a polyol ester 3970 (specifically, CRODA saturated polyol ester Priolube 3970), and the antioxidant is a mixture of an amine antioxidant L57 and a phenolic antioxidant L115 with a mass ratio of 1:1.2.

[0093] S2, cooling the mixture A in step S1 to 60°C, then adding 1kg of extreme pressure anti-wear agent triphenylthiophosphate TPPT and 1kg of rust inhibitor phosphate amine mixed solution 349, stirring for 10 minutes, then adding 20kg of thickener silicon dioxide R972 and 3kg of Peek-based composite additives, mixing and stirring for 40 minutes, cooling, and preparing high temperature resistant grease for gears;

[0094] Wherein, the Peek-based composite additive in step S2 is prepared by the following method:

[0095] The hydrogenated styrene isoprene copolymer and ethyl acetate were mixed in a mass ratio of 1:0.3, and then polyetheretherketone Peek was added and mixed, and then the porous polyester-silica composite microspheres prepared in Preparation Example 1 were added, and after stirring, they were immersed in ultrasonic conditions (ultrasonic power 40w) for 30 minutes, and then dried at 90°C to obtain a Peek-based composite additive, wherein the added mass ratio of polyetheretherketone to hydrogenated styrene isoprene copolymer was 1:0.3, and the added mass ratio of porous polyester-silica composite microspheres to polyetheretherketone was 1:3.

[0096] Embodiment 4-6

[0097] A method for preparing a high temperature resistant grease for gears is carried out according to the method in Example 1, except that the Peek-based composite additive in step S2 is the Peek-based composite additive prepared in Preparation Examples 4-6.

[0098] Comparative Example 1

[0099] A method for preparing a high temperature resistant grease for gears is carried out according to the method in Example 1, except that the Peek-based composite additive in step S2 is the Peek-based composite additive prepared in Comparative Preparation Example 1.

[0100] Comparative Example 2

[0101] A method for preparing a high temperature resistant grease for gears is carried out according to the method in Example 1, except that no Peek-based composite additive is added in step S2.

[0102] Comparative Example 3

[0103] A method for preparing a high temperature resistant grease for gears is carried out according to the method in Example 1, except that in step S2, an equal amount of Peek-based composite additive is replaced by Peek.

[0104] Comparative Example 4

[0105] A method for preparing a high-temperature resistant grease for gears is carried out according to the method in Example 1, except that in step S2, the Peek-based composite additive is obtained by directly mixing a polyester primary product and Peek in a mass ratio of 1:2, and the polyester primary product is the polyester primary product prepared in step 1) in comparative preparation example 1.

[0106] Comparative Example 5

[0107] A method for preparing a high-temperature resistant grease for gears is carried out according to the method in Example 1, except that in step S2, the Peek-based composite additive is obtained by directly mixing a polyester primary product and Peek in a mass ratio of 1:2, and the polyester primary product is the polyester primary product prepared in step 1) in Preparation Example 1.

[0108] Performance Testing

[0109] The greases prepared in the examples and comparative examples of the present application were tested for dropping point according to GB / T 4929-1985. In addition, the PD value of the greases was tested by a four-ball test (120° C.). The test results are shown in Table 1 below.

[0110] Table 1:

[0111] Test items Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Dropping point / ℃ 358 350 355 342 315 320 PD value / kgf 446 440 444 428 406 414 Test items Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 — Dropping point / ℃ 234 208 216 225 246 — PD value / kgf 300 262 276 284 312 —

[0112] Referring to Table 1 above, it can be seen that the grease prepared in the present application has a dropping point of more than 300°C, and has excellent lubrication performance at high temperatures, excellent high temperature resistance, good stability at high temperatures, and will not soften and flow, affecting the lubrication effect. Referring to the test results of Examples 1 and 4, when the polyester primary product is prepared, the monomer is selected to contain at least dimethyl terephthalate monomer, which is more conducive to improving the compatibility of Peek and grease, and the final grease has a higher dropping point and better high temperature resistance. Combined with the test results of Examples 5 and 6, when the polyester primary product is pore-formed to prepare porous polyester microspheres, the polyester primary product in the high temperature molten state is directly cooled or pore-formed by a pore-forming agent, and the high temperature resistance of the final grease is lower than that of Example 1. The polyester primary product is first pore-formed by a pore-forming agent and then rapidly cooled, which is conducive to the adjustment of the pore structure and has an effect on the distribution of Peek, thereby affecting the high temperature resistance of the final product.

[0113] Referring to the test results in Example 1 and Comparative Example 1, when porous polyester microspheres are added in the preparation of Peek-based composite additives without using silica as a skeleton, the high temperature resistance of the final grease is significantly reduced. On the one hand, silica R972 as a skeleton further improves the compatibility of Peek and grease, and on the other hand, silica R972 as a skeleton significantly improves the high temperature resistance of porous polyester-silica microspheres; Referring to the test results in Example 1 and Comparative Example 2, it can be seen that when the Peek-based composite additive is not added to the raw material, the dropping point of the grease is low and the high temperature resistance is significantly reduced;

[0114] Combined with the test results in Comparative Example 3, when only Peek is added to improve the dropping point, the dropping point of the grease is improved compared to that in Comparative Example 2, but it is far inferior to the performance in Example 1. Although Peek can improve the dropping point of the grease, its poor compatibility leads to uneven distribution in the grease, and the improvement in high temperature resistance is limited. It is also found that the grease prepared will show stratification after being placed for one month, while the grease prepared in the example of the present application will not show stratification after being placed for half a year.

[0115] Combined with the test results of Example 1, Comparative Examples 4 and 5, when Peek and a polyester pre-product without a silica skeleton were directly added in Comparative Example 4, the dropping point of the grease was significantly lowered compared with that in Example 1, and the polyester pre-product had limited improvement on the compatibility between Peek and the grease. When Peek and a polyester pre-product containing a silica skeleton were directly added in Comparative Example 5, the dropping point of the grease was significantly lowered compared with that in Example 1. Although the dropping point was improved compared with that in Comparative Example 4, the greases prepared in Comparative Examples 5 and 4 showed stratification after being placed for one month, and the compatibility between Peek and the grease was significantly reduced. The polyester pre-product had limited improvement on the compatibility between Peek and the grease. In Example 1, when Peek was loaded on porous polyester microspheres and added, the compatibility between Peek and the grease could be significantly improved.

[0116] 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 high temperature resistant grease for gears, characterized in that: It includes the following raw materials in parts by weight: 75-90 parts of synthetic oil PAO, 5-10 parts of ester base oil, 10-20 parts of thickener, 0.1-2 parts of antioxidant, 0.2-1 parts of extreme pressure anti-wear agent, 0.1-1 parts of rust inhibitor, 0.5-3 parts of Peek-based composite additives; Wherein, the Peek-based composite additive is prepared by the following method: The hydrogenated styrene isoprene copolymer and ethyl acetate are mixed in a mass ratio of 1:(0.2-0.3), and then polyetheretherketone is added and mixed, and then porous polyester-silica composite microspheres are added, and after stirring, the mixture is immersed in an ultrasonic condition for 20-30 minutes, and then dried at 80-90° C. to obtain a Peek-based composite additive, wherein the mass ratio of polyetheretherketone to hydrogenated styrene isoprene copolymer is 1:(0.2-0.3), and the mass ratio of porous polyester-silica composite microspheres to polyetheretherketone is 1:(2-3); The porous polyester-silicon dioxide composite microspheres are prepared by the following method: 1) Mix carboxylic acid monomer and polyol monomer as monomer raw materials, then heat to 170-185°C, then add catalyst and hydrophobic silica, heat to 200-220°C and react at 0.06-0.08MPa pressure for 2-3h to obtain polyester primary product; 2) Sodium bicarbonate is mixed with ethyl acetate and dichloromethane to prepare a pore-forming agent, and then the polyester primary product and the pore-forming agent are fully mixed and stirred, and then heated to 90-130° C., and then directly placed in 3-10° C. water, cooled, and cut to obtain porous polyester-silicon dioxide composite microspheres; When preparing porous polyester-silica composite microspheres, the mass ratio of the added carboxylic acid monomer to the polyol monomer in step 1) is 1:(1.2-1.4); The carboxylic acid monomer is selected from dimethyl terephthalate or one or more of dimethyl terephthalate and terephthalic acid, and isophthalic acid; the polyol monomer is selected from one or more of ethylene glycol, propylene glycol, and 1,4-butanediol.

2. The high temperature resistant lubricating grease for gears according to claim 1, characterized in that: When preparing porous polyester-silica composite microspheres, the amount of hydrophobic silica added in step 1) is 30-40wt% of the monomer raw material, and the amount of catalyst added is 0.3-0.5wt% of the monomer raw material; In step 2), the mass ratio of sodium bicarbonate to ethyl acetate and dichloromethane is 1:(8-10):(4-6), and the amount of pore-forming agent added is 3-5wt% of the amount of polyester primary product added.

3. The high temperature resistant lubricating grease for gears according to claim 2, characterized in that: The hydrophobic silica is silica R972, and the catalyst is a mixture of p-toluenesulfonic acid and titanate catalyst.

4. The high temperature resistant lubricating grease for gears according to claim 1, characterized in that: The thickener is silicon dioxide R972; The antioxidant is selected from one or more of amine antioxidants and phenolic antioxidants; The extreme pressure anti-wear agent is a phosphate ester extreme pressure anti-wear agent; The rust inhibitor is an amine rust inhibitor.

5. The high temperature resistant lubricating grease for gears according to claim 1, characterized in that: The synthetic oil PAO is selected from PAO40 and PAO10 with a mass ratio of 1: (1.8-2.2); The antioxidant is a mixture of an amine antioxidant and a phenolic antioxidant in a mass ratio of 1:(0.8-1.2); The extreme pressure anti-wear agent is triphenylthiophosphate.

6. A method for preparing a high temperature resistant lubricating grease for gears as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Mix the synthetic oil PAO and the ester base oil, heat to 45-60°C, stir for 30-40 minutes, then add the antioxidant and heat to 70-80°C, stir for 15-25 minutes; S2. Cool to 50-60°C and then add extreme pressure anti-wear agent and rust inhibitor, stir for 10-20 minutes, then add thickener and Peek-based composite additive, mix and stir for 20-40 minutes, cool, and obtain high temperature resistant grease for gears.