Polyurea lubricating grease and preparation method thereof

Abstract

The invention provides polyurea lubricating grease and a preparation method thereof. The polyurea lubricating grease disclosed by the invention comprises the following components in percentage by weight on the basis of the total mass of the lubricating grease: 0.1%-10% of an antioxidant, 0.1%-10% of an anti-rust agent, 0.1%-10% of an extreme pressure agent, 0.1%-10% of a multi-effect additive, 5%-25% of a polyurea thickening agent and 70%-95% of pentaerythritol ester, the pentaerythritol ester comprises the following components in percentage by mass: 5 to 50 percent of pentaerythritol ester as shown in a formula (I) and 50 to 95 percent of pentaerythritol ester as shown in a formula (II), wherein an R group is C1-C14 straight chain or branched chain alkylene; the polyurea lubricating grease provided by the invention has the advantages of excellent high-temperature oxidation resistance, excellent low-temperature performance, long service life, good colloid stability, good corrosion resistance and good rust resistance, and can meet the use requirements of long-life lubricating grease.

Description

Technical Field

[0001] The present invention relates to lubricating grease, in particular to polyurea lubricating grease and a preparation method thereof. Background Art

[0002] Polyurea grease is widely used in electrical appliances, metallurgy, food, automobile, papermaking and other industries due to its good oxidation stability and thermal stability.

[0003] In recent years, there have been numerous reports on the formulation and process of polyurea greases. CN 102585970B uses a mixed organic amine of aliphatic amine, cycloalkylamine, and aromatic amine to prepare a polyurea grease with high mechanical stability. CN 102827667A uses a mixed oil of PAO and highly hydrocracking wax as a base oil, adds alkylphenol polyoxyethyl ether as a dispersant, and uses a programmed temperature method to prepare a low-noise polyurea grease. CN 104059742A uses organic amines and diisocyanates to control the fiber structure through programmed temperature to prepare a low-noise polyurea grease. CN 116891771A uses erucamide as an anti-wear agent to provide a polyurea grease that can meet the requirements of automotive bearings. CN 111303966A uses refined mineral oil and cycloalkylamine and aliphatic amine to react with diisocyanate to form a thickener, providing a motor bearing grease with a low thickener content. CN 112375607A prepares a tetraurea grease by controlling the ratio of isocyanate, monoamine and diamine and adding an alcohol structure modifier. However, none of the above greases involve the antioxidant properties and low-temperature performance of the grease at -60°C.

[0004] Developing polyurea grease with a wider operating temperature range and better oxidation stability remains one of the research and development directions of those skilled in the art. Summary of the Invention

[0005] The invention provides a polyurea grease and a preparation method thereof.

[0006] The polyurea grease of the present invention comprises, based on the total mass of the grease, 0.1% to 10% of an antioxidant, 0.1% to 10% of a rust inhibitor, 0.1% to 10% of an extreme pressure agent, 0.1% to 10% of a multi-effect additive, 5% to 25% of a polyurea thickener, and 70% to 95% of a pentaerythritol ester; the pentaerythritol ester comprises, by mass, 5% to 50% of a pentaerythritol ester represented by formula (I) and 50% to 95% of a pentaerythritol ester represented by formula (II):

[0007]

[0008] The R group is C1~C 14Each R' group is independently selected from a C3 to C9 straight chain or branched chain alkyl group.

[0009] According to the present invention, the R group is preferably a C2 to C8 straight chain or branched alkylene group; each R' group is preferably selected from two or more (for example, three or four) of a C3 straight chain or branched alkyl group, a C4 straight chain or branched alkyl group, a C5 straight chain or branched alkyl group, a C6 straight chain or branched alkyl group, a C7 straight chain or branched alkyl group, a C8 straight chain or branched alkyl group, and a C9 straight chain or branched alkyl group, more preferably selected from a C3 straight chain alkyl group, a C4 straight chain alkyl group, a C5 straight chain alkyl group, a C6 straight chain alkyl group, a C7 straight chain alkyl group, a C8 straight chain alkyl group. % of C5 linear alkyl, 5.0 mol% to 45.0 mol% of C6 linear alkyl, 0 to 30.0 mol% of C7 linear alkyl, 0 to 15.0 mol% of C8 linear alkyl, and 0 to 10.0 mol% of C9 linear alkyl.

[0010] According to the present invention, the pentaerythritol ester preferably comprises, by mass, 5% to 25% of the pentaerythritol ester represented by formula (I) and 75% to 95% of the pentaerythritol ester represented by formula (II).

[0011] The preparation method of pentaerythritol ester of the present invention comprises the following steps:

[0012] (1) Excessive monopentaerythritol and C 3～16 The dibasic fatty acid undergoes esterification reaction to obtain esterification product A1;

[0013] (2) Esterification product A1 and excess C 4～10 The monobasic fatty acids undergo esterification and the products are collected.

[0014] According to the present invention, in step (1), the monopentaerythritol and C 3～16 The molar ratio of the dibasic fatty acid can be (2.05-100):1, preferably (3-60):1, and more preferably (3-30):1; in step (2), the hydroxyl group and C in the esterification product A1 4～10 The molar ratio of the carboxyl groups in the monobasic fatty acid may be 1:(1.05-1.30), preferably 1:(1.10-1.20).

[0015] According to the present invention, the reaction temperature of step (1) is 50-180°C, preferably 80-150°C, and the reaction time is 1-20h, preferably 2-10h; the reaction temperature of step (2) is 50-250°C, preferably 100-220°C, and the reaction time is until water is no longer produced, which can generally be 1-20h, or 5-10h.

[0016] According to the present invention, the dibasic fatty acid may be one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid and hexadecanedioic acid.

[0017] According to the present invention, the monobasic fatty acid is preferably selected from two or more (for example, three or four) of n-butyric acid, isobutyric acid, n-pentanoic acid, isovaleric acid, n-hexanoic acid, isohexanoic acid, n-heptanoic acid, isoheptanoic acid, n-octanoic acid, isooctanoic acid, n-nonanoic acid, isononanoic acid, n-decanoic acid and isodecanoic acid, more preferably selected from two or more (for example, three or four) of n-butyric acid, n-pentanoic acid, n-hexanoic acid, n-heptanoic acid, n-octanoic acid, n-nonanoic acid and n-decanoic acid, further preferably, the monobasic fatty acid may include 0-10.0 mol% of n-butyric acid, 0-35.0 mol% of n-pentanoic acid, 30.0 mol%-75.0 mol% of n-hexanoic acid, 5.0 mol%-45.0 mol% of n-heptanoic acid, 0-30.0 mol% of n-octanoic acid, 0-15.0 mol% of n-nonanoic acid and 0-10.0 mol% of n-decanoic acid.

[0018] According to the present invention, a catalyst may be added to the esterification reaction in step (1) and / or step (2), and the catalyst includes one or more of concentrated sulfuric acid, sodium bisulfate, p-toluenesulfonic acid, zinc oxide, a cation exchange resin, an ionic liquid, stannous oxide, a titanate, and activated carbon. The amount of the catalyst added may be in accordance with the amount used in the esterification reaction in the prior art and is not particularly limited. The catalyst may be removed after the esterification reaction by methods well known in the art, such as alkali washing, water washing, and filtration, and is not particularly limited.

[0019] According to the present invention, a solvent may be added during the esterification reaction in step (1) and / or step (2). The solvent may be one or more of xylene, toluene, and cyclohexane. The amount of the solvent added may be in accordance with the amount used in the esterification reaction in the prior art and is not particularly limited. The solvent may be removed after the esterification reaction by methods well known in the art, such as distillation, and is not particularly limited.

[0020] According to the present invention, the esterification reaction in step (1) and / or step (2) can be carried out under nitrogen protection.

[0021] According to the present invention, preferably, in step (2), the esterification product A1 is reacted with an excess of C 4～10 The product of the esterification reaction of the monobasic fatty acid is purified by one or more of the following methods: reduced pressure distillation, alkaline washing, dehydration, decolorization, and filtration. After the purification, a mixture of the pentaerythritol ester represented by formula (I) and the pentaerythritol ester represented by formula (II) with higher purity can be obtained.

[0022] The pentaerythritol ester of the present invention has a high viscosity index (>130), a low pour point (<-60°C), a relatively low kinematic viscosity at -40°C (<10000mm 2 / s) and good high temperature oxidation stability.

[0023] According to the present invention, the antioxidant is an amine antioxidant, for example, one or more of diphenylamine, diisooctyldiphenylamine, β-naphthylamine, N-phenyl-α-naphthylamine, N-phenyl-β-naphthylamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, N,N'-di-β-naphthyl-p-phenylenediamine and N,N'-di-sec-butyl-p-phenylenediamine can be selected; the rust inhibitor is an organic amine rust inhibitor, for example, one or more of N-oleoylsarcosine octadecylamine salt, 2-aminoethylheptadecenylimidazoline dodecenylbutanediamine, One or more of dodecenylbutanediamine and octadecylamine oleate; the extreme pressure agent is an organic phosphide, for example, one or more of tricresyl phosphate, di-n-butyl phosphite and triphenyl phosphate can be selected; the multi-effect additive is a dithiocarbamate, for example, one or more of diamyldithiocarbamate zinc, diamyldithiocarbamate antimony, diamyldithiocarbamate lead, dibutyldithiocarbamate zinc, dibutyldithiocarbamate antimony, dibutyldithiocarbamate lead and dibutyldithiocarbamate oxymolybdenum can be selected.

[0024] According to the present invention, the polyurea thickener is the reaction product of an organic amine and a diisocyanate. The molar ratio between the organic amine and the diisocyanate can be 1:0.4-1.1, preferably 1:0.5-1. The organic amine can be a mixture of aliphatic amine and aromatic amine, and the molar ratio between the two can be 1:0.2-3, preferably 1:0.5-2. The carbon number of the aliphatic amine can be 10-20, preferably 12-18, for example, one or more of dodecylamine, tetradecylamine, hexadecylamine and octadecylamine can be selected; the carbon number of the aromatic amine can be 6-10, for example, one or more of aniline, p-toluidine, p-phenylenediamine, m-phenylenediamine and ethylaniline can be selected. The structure of the diisocyanate is O=CN-R-NC=O, wherein the R group can be C6-C 30 Aryl or C6~C 30 Alkyl, preferably C7~C 13Aryl or C7~C 13 The diisocyanate can be selected from one or more of toluene diisocyanate (TDI), diphenylmethane-4,4'-diisocyanate (MDI) and 1,6-hexamethylene diisocyanate (HDI).

[0025] The preparation method of the polyurea grease of the present invention comprises:

[0026] The organic amine is added to the first part of pentaerythritol ester and heated to 50-80°C to completely dissolve the organic amine; the diisocyanate is added to the second part of pentaerythritol ester and heated to dissolve the diisocyanate; the two solutions are mixed and stirred at 20-60°C and reacted for 10-30 minutes; the temperature is raised to 180-220°C and high-temperature refining is performed for 5-20 minutes; the third part of pentaerythritol ester is added and cooled to 90-130°C; an antioxidant, a rust inhibitor, an extreme pressure agent and a multi-effect additive are added, the mixture is stirred evenly and ground into fat.

[0027] According to the present invention, the sum of the masses of the first part of pentaerythritol ester, the second part of pentaerythritol ester and the third part of pentaerythritol ester is the total mass of all pentaerythritol esters, and the mass ratio among the three can be 1:0.5-2:0.5-2.

[0028] The polyurea grease of the present invention has excellent high-temperature oxidation resistance, low-temperature performance and a long service life, and also has good colloid stability, corrosion resistance and rust resistance, and can meet the use requirements of long-life grease. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the infrared spectrum of monopentaerythritol raw material.

[0030] Figure 2 The infrared spectrum of the pentaerythritol ester product prepared in Example 1 is shown in FIG.

[0031] Figure 3 This is the Fourier transform ion cyclotron resonance spectrum of the pentaerythritol ester product prepared in Example 1. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below by way of examples, but the present invention is not limited thereto.

[0033] The present invention is concerned with the monopentaerythritol, C 4～10 Monobasic fatty acids, C 3～16 The source of the dibasic fatty acid is not particularly limited, and any commercially available product or homemade product of the above raw materials well known to those skilled in the art can be used.

[0034] Example 1

[0035] In a 1 L four-necked flask equipped with a stirring rod, a thermometer, a condenser, and a water separator, 50.0 g of monopentaerythritol (0.367 mol), 4.3 g of adipic acid (0.027 mol), 80 ml of xylene, and 1.5 g of tetrabutyl titanate catalyst were added, and the mixture was reacted at 150° C. for 4 h under nitrogen protection to obtain an esterification product A1, which was then cooled to room temperature. Then, 36.0 g of n-pentanoic acid, 110.0 g of n-hexanoic acid, 58.0 g of n-heptanoic acid, and 2.0 g of tetrabutyl titanate catalyst were added, and under nitrogen protection, the reaction temperature was heated to 150° C., then raised to 220° C. using a temperature program of 10° C. / h, and reacted until no water was produced to obtain a crude esterification product B1. The mixture was cooled to room temperature, subjected to reduced pressure distillation, alkali washing, water washing, dehydration, decolorization, and filtration to obtain the pentaerythritol ester of the present invention, which was labeled J1.

[0036] Infrared spectra of the monopentaerythritol raw material and the pentaerythritol ester product prepared in Example 1 were respectively tested. The infrared spectra of the monopentaerythritol raw material were shown in FIG. Figure 1 The infrared spectrum of the pentaerythritol ester product obtained in Example 1 is shown in FIG. Figure 2 By comparison, in the infrared spectrum of monopentaerythritol, 3200~3400cm -1 is the absorption peak of the alcoholic hydroxyl group in monopentaerythritol; the 3200-3400 cm-1 peak does not exist in the infrared spectrum of the pentaerythritol ester product prepared in Example 1. -1 Absorption peak, including 1744cm -1 It is the stretching vibration peak of the C=O bond in the pentaerythritol ester product prepared in Example 1, indicating that the excess monobasic fatty acid in step (2) causes the excess monopentaerythritol in step (1) to react completely, and there is no alcoholic hydroxyl group in the product.

[0037] Example 2

[0038] In a 1 L four-necked flask equipped with a stirring rod, a thermometer, a condenser, and a water separator, 50.0 g of monopentaerythritol (0.367 mol), 8.6 g of adipic acid (0.06 mol), 100 ml of xylene, and 2.0 g of p-toluenesulfonic acid catalyst were added, and the mixture was reacted at 150° C. for 7 h under nitrogen protection to obtain an esterification product A1, which was then cooled to room temperature. Then, 56.0 g of n-pentanoic acid, 92.0 g of n-hexanoic acid, 23.0 g of n-heptanoic acid, 25.5 g of n-octanoic acid, and 2.0 g of p-toluenesulfonic acid catalyst were added, and under nitrogen protection, the reaction temperature was heated to 150° C., then raised to 220° C. using a temperature program of 10° C. / h, and reacted until no water was produced to obtain a crude esterification product B1. The mixture was cooled to room temperature, subjected to reduced pressure distillation, alkali washing, water washing, dehydration, decolorization, and filtration to obtain the pentaerythritol ester of the present invention, which is labeled J2.

[0039] Example 3

[0040] In a 1 L four-necked flask equipped with a stirring rod, a thermometer, a condenser, and a water separator, 50.0 g of monopentaerythritol (0.367 mol), 7.6 g of malonic acid (0.073 mol), 4.0 g of suberic acid (0.023 mol), 100 ml of xylene, and 1.5 g of tetrabutyl titanate catalyst were added, and the mixture was reacted at 150° C. for 7 h under nitrogen protection to obtain an esterification product A1, which was then cooled to room temperature. Then, 36.0 g of n-pentanoic acid, 98.5 g of n-hexanoic acid, 46.0 g of n-heptanoic acid, 12.7 g of n-octanoic acid, and 2.0 g of tetrabutyl titanate catalyst were added. Under nitrogen protection, the reaction temperature was heated to 150° C., then increased to 220° C. using a temperature program of 10° C. / h, and reacted until no water was produced to obtain a crude esterification product B1. The mixture was cooled to room temperature, subjected to reduced pressure distillation, alkali washing, water washing, dehydration, decolorization, and filtration to obtain the pentaerythritol ester of the present invention, which was labeled J3.

[0041] The pentaerythritol ester prepared in Example 1 was subjected to Fourier transform ion cyclotron resonance (FTIR) analysis using an electrospray ionization source (ESI+) in positive ion mode. The test conditions were: ion transport capillary temperature of 350°C, spray voltage of 2.8 kV, m / z scanning range of 100-1500, and mass resolution of 70,000. The measured spectrum is shown in FIG. Figure 3 .from Figure 3 It can be seen that C 26 H 46 O8~C 36 H 36 O8 represents the ester formed by monopentaerythritol and monobasic fatty acid (hereinafter referred to as monobasic acid ester), C 51 H 88 O 16 ~C 59 H 104 O 16 with C 73 H 124 O 24 ~C 79 H 136 O 24 It represents the ester formed by the esterification product of adipic acid and monopentaerythritol and then reacting with a monobasic fatty acid (hereinafter abbreviated as dibasic acid ester).

[0042] The physical and chemical properties of the pentaerythritol ester of the present invention are illustrated by taking commercial pentaerythritol ester as comparative example 1. The commercial pentaerythritol ester is mixed pentaerythritol ester MIXPE1 produced by Zhejiang Quzhou Chemical Co., Ltd., and its kinematic viscosity at 100°C is 5.02 mm 2 / s.

[0043] The pentaerythritol esters of Examples 1-3 and the pentaerythritol ester of Comparative Example 1 were evaluated for their physical and chemical properties, and the results are shown in Table 1. The content distribution of the pentaerythritol esters prepared in Examples 1-3 and the pentaerythritol ester of Comparative Example 1 was determined according to the method for determining the boiling range distribution of petroleum fractions (NB / SH / T 0829), i.e., the content of the monobasic and dibasic esters in Examples 1-3 or the content of the monopentaerythritol ester and dipentaerythritol ester in Comparative Example 1 was determined. The results are also shown in Table 1. For example, the results of the product of Example 1 showed that the content of the ester formed by monopentaerythritol and a monobasic fatty acid (i.e., the monobasic ester) was 88.2% (with a boiling range of 350-500°C), and the content of the ester formed by the esterification product of adipic acid and monopentaerythritol and then reacting with a monobasic fatty acid (i.e., the dibasic ester) was 11.8% (with a boiling range of >500°C).

[0044] As can be seen from Table 1, compared with the comparative pentaerythritol ester MIXPE1, the pentaerythritol ester of the present invention has a lower pour point (≤-66°C) and a higher viscosity index (≥135), indicating that the pentaerythritol ester base oil of the present invention has better low-temperature fluidity and viscosity-temperature properties.

[0045] Table 1 Physical and chemical indicators of pentaerythritol esters

[0046]

[0047] The sources of the main raw materials used in the greases prepared below are as follows:

[0048] Octadecylamine, hexadecylamine, aniline, m-phenylenediamine, p-toluidine, MDI, HDI, Inokite Technology Co., Ltd.

[0049] Diphenylamine, Henan Mingxuan Chemical Products Co., Ltd.

[0050] Diisooctyldiphenylamine, Zhejiang Jinjinle Chemical Co., Ltd.

[0051] N-phenyl-α-naphthylamine, Zhejiang Jinjinle Chemical Co., Ltd.

[0052] N-Oleoylsarcosine octadecylamine salt, Nanjing Shengxiong Chemical Co., Ltd.

[0053] 2-Aminoethyl heptadecenyl imidazoline dodecenylbutanediamine, Jinan Flanders Chemical Co., Ltd.

[0054] Tricresyl phosphate, Shandong Shengcang Chemical Technology Co., Ltd.

[0055] Di-n-butyl phosphite, Shandong Liang New Material Technology Co., Ltd.

[0056] Triphenyl phosphate, Jinan Rongzheng Chemical Co., Ltd.

[0057] Zinc diamyl dithiocarbamate, antimony diamyl dithiocarbamate, antimony dibutyl dithiocarbamate, Hubei Jusheng Technology Co., Ltd.

[0058] Example I-1 of preparing grease

[0059] Raw material components: 85 g of pentaerythritol ester product J1 of Example 1; 6.4 g of octadecylamine; 2.6 g of p-toluidine; 6.0 g of MDI; 0.5 g of diphenylamine; 2 g of N-oleoylsarcosine octadecylamine salt; 2 g of tricresyl phosphate; and 2 g of zinc diamyldithiocarbamate.

[0060] Preparation method: Add 6.4g of octadecylamine and 2.6g of p-toluidine to 30g of pentaerythritol ester J1, heat to 60°C to completely dissolve the organic amine; add 6.0g of MDI to 30g of pentaerythritol ester J1, heat to dissolve it; mix and stir the two solutions at 40°C and react for 20 minutes; heat to 200°C and refining at high temperature for 10 minutes; add the remaining pentaerythritol ester J1, cool to 110°C, add 0.5g of diphenylamine, 2g of N-oleoylsarcosine octadecylamine salt, 2g of tricresyl phosphate, and 2g of zinc diamyldithiocarbamate, stir evenly, and grind into fat on a three-roll mill.

[0061] Example I-2 of preparing grease

[0062] Raw material components: 80 g of the pentaerythritol ester product J2 of Example 2; 10.6 g of hexadecylamine; 2.4 g of m-phenylenediamine; 7.0 g of HDI; 1 g of N-phenyl-α-naphthylamine; 1 g of 2-aminoethylheptadecenylimidazoline dodecenylbutanediamine; 1 g of di-n-butyl phosphite; and 4 g of dipentyl antimony dithiocarbamate.

[0063] Preparation method: Add 10.6g hexadecylamine and 2.4g m-phenylenediamine to 30g pentaerythritol ester J2, heat to 60°C to completely dissolve the organic amine; add 7.0g HDI to 30g pentaerythritol ester J2, heat to dissolve; mix and stir the two solutions at 20°C, react for 10 minutes; heat to 200°C and carry out high-temperature refining for 5 minutes; add the remaining pentaerythritol ester J2, cool to 100°C, add 1g N-phenyl-α-naphthylamine, 1g 2-aminoethylheptadecenylimidazoline dodecenylbutanediamine, 1g di-n-butyl phosphite, and 4g dipentyl antimony dithiocarbamate, stir evenly, and grind into fat using a three-roll mill.

[0064] Example I-3 of preparing grease

[0065] Raw material components: 88 g of the pentaerythritol ester product J3 of Example 3; 3.9 g of octadecylamine; 2.7 g of aniline; 5.4 g of MDI; 0.5 g of diisooctyldiphenylamine; 1 g of N-oleoylsarcosine octadecylamine salt; 2 g of triphenyl phosphate; and 3 g of antimony dibutyldithiocarbamate.

[0066] Preparation method: Add 3.9g of octadecylamine and 2.7g of aniline to 30g of pentaerythritol ester J3, heat to 60°C to completely dissolve the organic amine; add 5.4g of MDI to 30g of pentaerythritol ester J3, heat to dissolve it; mix and stir the two solutions at 60°C and react for 30 minutes; heat to 200°C and refining at high temperature for 10 minutes; add the remaining pentaerythritol ester J3, cool to 110°C, add 0.5g of diisooctyldiphenylamine, 1g of N-oleoylsarcosine octadecylamine salt, 2g of triphenyl phosphate, and 3g of antimony dibutyl dithiocarbamate, stir evenly, and grind into fat on a three-roll mill.

[0067] Comparative Example D-1 for preparing grease

[0068] A lubricating grease was prepared according to the method of Example I-1, except that the pentaerythritol ester J1 was replaced with the mixed pentaerythritol ester MIXPE1.

[0069] The performance of the above-mentioned grease examples and comparative examples was evaluated using the following method:

[0070] The dropping point was determined using the GB / T 3498 method;

[0071] The cone penetration was determined using the GB / T 269 method;

[0072] The oxidation stability was determined using the SH / T 0325 method;

[0073] The oil separation of steel mesh is determined using the NB / SH / T 0324 method;

[0074] GB / T 7326 method was used to determine copper corrosion;

[0075] The anti-corrosion performance was determined using the GB / T 5018 method;

[0076] The low temperature performance is determined using the SH / T 0338 method;

[0077] The bearing life is determined using the SH / T 0773 method;

[0078] The evaluation results are shown in Table 2.

[0079] Table 2 Performance evaluation of grease

[0080]

Claims

1. Polyurea grease, comprising, based on the total mass of the grease, 0.1% to 10% of an antioxidant, 0.1% to 10% of a rust inhibitor, 0.1% to 10% of an extreme pressure agent, 0.1% to 10% of a multi-effect additive, 5% to 25% of a polyurea thickener, and 70% to 95% of a pentaerythritol ester; the pentaerythritol ester comprising, by mass, 5% to 50% of a pentaerythritol ester of formula (I) and 50% to 95% of a pentaerythritol ester of formula (II): The R group is C1~C 14 Each R' group is independently selected from a C3 to C9 straight chain or branched chain alkyl group.

2. The polyurea grease according to claim 1, characterized in that The R group is a straight chain or branched chain alkylene group of C2 to C8; each R' group is selected from two or more of a straight chain or branched chain alkyl group of C3, a straight chain or branched chain alkyl group of C4, a straight chain or branched chain alkyl group of C5, a straight chain or branched chain alkyl group of C6, a straight chain or branched chain alkyl group of C7, a straight chain or branched chain alkyl group of C8, and a straight chain or branched chain alkyl group of C9.

3. The polyurea grease according to claim 1, characterized in that The pentaerythritol ester comprises, by mass, 5.0% to 25% of the pentaerythritol ester represented by formula (I) and 75% to 95% of the pentaerythritol ester represented by formula (II).

4. The polyurea grease according to claim 1, characterized in that The preparation method of the pentaerythritol ester comprises the following steps: (1) Excessive monopentaerythritol and C 3～16 The dibasic fatty acid undergoes esterification reaction to obtain esterification product A1; (2) Esterification product A1 and excess C 4～10 The monobasic fatty acids undergo esterification reaction and the products are collected.

5. The polyurea grease according to claim 4, characterized in that In step (1), the monopentaerythritol and C 3～16 The molar ratio of the dibasic fatty acid is (2.05-100):1; in step (2), the hydroxyl group and C 4～10 The molar ratio of the carboxyl group in the monobasic fatty acid is 1:(1.05~1.30).

6. The polyurea grease according to claim 4, characterized in that The reaction temperature of step (1) is 50-180° C., and the reaction time is 1-20 h; the reaction temperature of step (2) is 50-250° C., and the reaction time is until water is no longer produced.

7. The polyurea grease according to claim 4, characterized in that The dibasic fatty acid is one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, and hexadecanedioic acid; the monobasic fatty acid is selected from two or more of n-butyric acid, isobutyric acid, n-valeric acid, isovaleric acid, n-hexanoic acid, isohexanoic acid, n-heptanoic acid, isoheptanoic acid, n-octanoic acid, isooctanoic acid, n-nonanoic acid, isononanoic acid, n-decanoic acid, and isodecanoic acid.

8. The polyurea grease according to claim 4, characterized in that Adding a catalyst to the esterification reaction of step (1) and / or step (2), wherein the catalyst is selected from one or more of concentrated sulfuric acid, sodium bisulfate, p-toluenesulfonic acid, zinc oxide, cation exchange resin, ionic liquid, stannous oxide, titanate and activated carbon; and / or, The esterification reaction in step (1) and / or step (2) is carried out under nitrogen protection.

9. The polyurea grease according to any one of claims 1 to 8, characterized in that: The antioxidant is an amine antioxidant; the rust inhibitor is an organic amine rust inhibitor; the extreme pressure agent is an organic phosphide; the multi-effect additive is a dithiocarbamate; and the polyurea thickener is a reaction product of an organic amine and a diisocyanate.

10. The polyurea grease according to claim 9, characterized in that The antioxidant is one or more of diphenylamine, diisooctyldiphenylamine, β-naphthylamine, N-phenyl-α-naphthylamine, N-phenyl-β-naphthylamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, N,N'-di-β-naphthyl-p-phenylenediamine and N,N'-di-sec-butyl-p-phenylenediamine; the rust inhibitor is one or more of N-oleoylsarcosine octadecylamine salt, 2-aminoethylheptadecenylimidazoline dodecenylbutanediamine, dodecenylbutanediamine and octadecylamine oleate; the extreme pressure agent is One or more of tricresyl phosphate, di-n-butyl phosphite and triphenyl phosphate; the multi-effect additive is one or more of diamyl dithiocarbamate zinc, diamyl dithiocarbamate antimony, diamyl dithiocarbamate lead, dibutyl dithiocarbamate zinc, dibutyl dithiocarbamate antimony, dibutyl dithiocarbamate lead and dibutyl dithiocarbamate oxymolybdenum; the organic amine is a mixture of aliphatic amine and aromatic amine, the structure of the diisocyanate is O=CN-R-NC=O, wherein the R group is C6~C 30 Aryl or C6~C 30 of alkyl.

11. The method for preparing the polyurea grease according to any one of claims 1 to 10, comprising: Add the organic amine to the first portion of pentaerythritol ester and heat to 50-80° C. to completely dissolve the organic amine; Add diisocyanate to the second part of pentaerythritol ester and heat to dissolve the diisocyanate; mix and stir the above two groups of solutions at 20-60°C and react for 10-30 minutes; heat to 180-220°C and perform high-temperature refining for 5-20 minutes; add the third part of pentaerythritol ester, cool to 90-130°C, add antioxidant, rust inhibitor, extreme pressure agent and multi-effect additive, stir evenly and grind into fat.

Images