Lubricant as well as application and preparation method thereof

Abstract

The invention discloses a lubricant as well as application and a preparation method thereof. A lubricant comprises: (i) at least 45.0 wt%, based on the weight of the lubricant, of an aromatic ester-based material; (ii) from 10.0% to 45.0% by weight, based on the weight of the lubricant, of polyisobutylene; (iii) an antioxidant comprising from 1.0 wt% to 15.0 wt%, based on the weight of the lubricant, of a first antioxidant having a melting point higher than 75 DEG C; and (iv) no more than 4.5% by weight of an anti-wear extreme pressure agent based on the weight of the lubricant. And the main performance indexes of the lubricant can be met at a low cost, the emission of smoke can be reduced, and the pollution to the environment can be reduced.

Description

Lubricant and its application and preparation method Technical Field

[0001] The present invention relates to the field of lubrication technology, in particular to a lubricant and its application and preparation method. Background Art

[0002] Some existing lubricants are less than ideal. For example, some lubricants are expensive, placing significant financial pressure on their users. Furthermore, during use, especially in high-temperature environments of 200°C to 250°C, some lubricants tend to produce significant amounts of smoke, polluting the environment and failing to meet stringent environmental standards. Correspondingly, the preparation methods for these lubricants are often unsatisfactory. Furthermore, these drawbacks often limit the application of these lubricants.

[0003] To address issues such as the above, Chinese patent applications Nos. CN105441164A, CN101240219A, CN105008500A, and CN105176638A, International Patent Application No. WO2008031393A2, and U.S. Patent Application No. US20140200169A1 have disclosed the research and development achievements of their respective inventors. However, in practice, existing lubricants, their applications, and preparation methods still have room for improvement.

[0004] Therefore, there is a need to improve existing lubricants and their application and preparation methods.

[0005] Summary of the Invention

[0006] The technical problems solved by the present invention include that there is room for improvement in the cost, smoke emission and other aspects of the existing lubricants and their applications and preparation methods.

[0007] One aspect of an embodiment of the present invention relates to a lubricant comprising: (i) at least 45.0 wt. % of an aromatic ester-based material, based on the weight of the lubricant; (ii) 10.0 wt. % to 45.0 wt. % of polyisobutylene, based on the weight of the lubricant; (iii) an antioxidant, comprising 1.0 wt. % to 15.0 wt. % of a first antioxidant having a melting point greater than 75° C., based on the weight of the lubricant; and (iv) no more than 4.5 wt. % of an extreme pressure antiwear agent, based on the weight of the lubricant.

[0008] In some embodiments, the first antioxidant has a melting point of 80°C to 165°C.

[0009] In some embodiments, the first antioxidant includes at least one first amine antioxidant.

[0010] In some embodiments, the first antioxidant includes at least one first aminic antioxidant and at least one first phenolic antioxidant.

[0011] In some embodiments, the first antioxidant comprises 1.0 wt % to 3.0 wt % of the first phenolic antioxidant based on the weight of the lubricant.

[0012] In some embodiments, the content of the first amine antioxidant is greater than that of the first phenolic antioxidant.

[0013] In some embodiments, the antioxidant comprises 1.0 wt % to 8.0 wt % of the first amine antioxidant based on the weight of the lubricant.

[0014] In some embodiments, the antioxidant includes a second antioxidant having a melting point not higher than 75°C.

[0015] In some embodiments, the antioxidant is substantially free of a second antioxidant having a melting point of no higher than 75°C.

[0016] In some embodiments, the antioxidant is present in an amount of 3.0 wt % to 8.0 wt % based on the weight of the lubricant.

[0017] In some embodiments, the first amine antioxidant includes at least one selected from the following: 4,4'-dioctyldiphenylamine, 4,4'-bis-(α,α-dimethylbenzyl)diphenylamine, N-phenyl-N'-(p-toluenesulfonyl)-p-phenylenediamine, N-(4-tert-butylphenyl-α-naphthylamine), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine, 4,4'-bis-(phenylisopropyl)diphenylamine, and 4,4'-diheptyldiphenylamine.

[0018] In some embodiments, the first phenolic antioxidant includes at least one selected from the following: pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 4,4'-thiobis(5-methyl-2-tert-butylphenol), 3-(3,5-di-tert-butyl-4-hydroxyphenyl) acrylate isooctyl ester, hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], and 2-propionic acid 3-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-1,6-hexanediol ester.

[0019] In some embodiments, the aromatic ester-based material is an aromatic ester of formula (I):

[0020] wherein R1 is a straight or branched chain alkyl group having 8 to 14 carbon atoms, and n is 3 or 4.

[0021] In some embodiments, the aromatic ester-based material is selected from esters of trimellitic acid, pyromellitic acid, trimellitic acid, and hemipyromellitic acid, wherein R1 is a linear or branched alkyl group having 8 to 12 carbon atoms.

[0022] In some embodiments, the aromatic ester-based material includes a trimellitic acid ester having a molecular weight of 500 g / mol to 1500 g / mol.

[0023] In some embodiments, the aromatic ester-based material is present in an amount of 55 wt % to 85 wt % based on the weight of the lubricant.

[0024] In some embodiments, the polyisobutylene is an unhydrogenated homopolymer having a number average molecular weight of 1000 g / mol to 3000 g / mol.

[0025] In some embodiments, the polyisobutylene is present in an amount of 28 wt % to 35 wt % based on the weight of the lubricant.

[0026] In some embodiments, the extreme pressure anti-wear agent is present in an amount of 0.1 wt % to 3.5 wt % based on the weight of the lubricant.

[0027] In some embodiments, the extreme pressure anti-wear agent is selected from at least two or three of the following: alkylated triphenyl thiophosphate, a mixture of tert-butylphenyl phosphate, an amine-neutralized phosphate, a dithiophosphate derivative, a triphenyl phosphate derivative, a triphenyl thiophosphate derivative, and an acidic phosphate amine salt.

[0028] In some embodiments, the lubricant is substantially free of Type I base oils, Type II base oils, Type III base oils, and / or polyalphaolefins.

[0029] In some embodiments, the lubricant has at least one of the following properties: a) the cumulative smoke volume in the first 120 minutes is less than 25g / m 3 ; b) PM10 concentration peak is lower than 500mg / m 3 , or less than 350mg / m 3 c) a kinematic viscosity at 40°C of at least 100 mm2 as measured by ASTM D445; 2 / s; d) a viscosity index of at least 115 measured according to ASTM D 2270; e) a flash point of at least 280°C; and f) an evaporation loss rate of about 50% or less measured after evaporation at 230°C for 72 hours.

[0030] Another aspect of an embodiment of the present invention relates to a lubricant comprising: (I) 55.0 wt % to 70 wt % of an aromatic ester-based material, based on the weight of the lubricant; (II) 28.0 wt % to 35.0 wt % of polyisobutylene, based on the weight of the lubricant; (III) 3.0 wt % to 8.0 wt % of an antioxidant, based on the weight of the lubricant, the antioxidant comprising a first antioxidant having a melting point greater than 75° C.; the first antioxidant comprising at least one first aminic antioxidant and, in some embodiments, at least one first phenolic antioxidant, and the content of the first aminic antioxidant is greater than or equal to the first phenolic antioxidant; and (IV) no more than 4.5 wt % of an extreme pressure anti-wear agent, based on the weight of the lubricant.

[0031] Yet another aspect of an embodiment of the present invention relates to the use of the lubricant as described herein for lubricating a chain, chain rollers or belt of a continuous press at a temperature of 200°C to 250°C.

[0032] Another aspect of an embodiment of the present invention relates to a method for preparing a lubricant as described in the present application, comprising the following steps: A) mixing the aromatic ester-based material, the polyisobutylene, the antioxidant, and the extreme pressure anti-wear agent; and B) stirring at a temperature not lower than the melting point of the first antioxidant for at least 30 minutes to obtain the lubricant.

[0033] If technical conditions permit, the technical features of the various embodiments of the present application can be combined arbitrarily to obtain new technical solutions within the scope of protection.

[0034] The embodiments of the present invention will be further described below with reference to the accompanying drawings and experimental examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG1 is a graph showing the change in PM10 concentration over time in the smoke test of the lubricant samples of Experimental Examples 1-5 and Comparative Examples 1-2 of the present invention. DETAILED DESCRIPTION

[0036] One aspect of an embodiment of the present invention relates to a lubricant comprising: (i) at least 45.0 wt. % of an aromatic ester-based material, based on the weight of the lubricant; (ii) 10.0 wt. % to 45.0 wt. % of polyisobutylene, based on the weight of the lubricant; (iii) an antioxidant, comprising 1.0 wt. % to 15.0 wt. % of a first antioxidant having a melting point greater than 75° C., based on the weight of the lubricant; and (iv) no more than 4.5 wt. % of an extreme pressure antiwear agent, based on the weight of the lubricant.

[0037] The technical solution of the embodiment of the present invention can help reduce smoke emissions while meeting various major indicators of lubricants at a lower cost, alleviate environmental pollution, and meet higher environmental protection requirements.

[0038] For example, aromatic ester-based materials and polyisobutylene are relatively low in cost, resulting in a relatively low cost lubricant according to the present invention. The experimental examples described below demonstrate that the lubricant according to the present invention, while meeting all key lubricant performance requirements, produces less smoke at high temperatures, causes less environmental pollution, and meets high environmental protection requirements.

[0039] In the embodiments of the present invention, unless otherwise specified, lubricants can provide lubrication, cooling assistance, rust prevention, cleaning, sealing, and cushioning. Lubricants can be applied between two objects in relative motion to reduce friction and wear caused by contact between the two objects. Lubricants can be used on various types of machinery and equipment to protect the machinery and workpieces. Lubricants can be liquid or semi-solid.

[0040] In the embodiments of the present invention, unless otherwise specified, weight percentage may be the percentage of the weight of a component to the total weight.

[0041] In the embodiments of the present application, "first", "second" and similar terms are not intended to indicate order, priority, importance, etc., but are only used to help distinguish the materials they modify, etc., and should not be understood as improper limitations on the scope of protection.

[0042] The antioxidant can help delay the oxidation of the base oil during storage and use, thereby extending the service life of the lubricant.

[0043] Referring to the experimental examples described below, when the antioxidant includes a first antioxidant having a melting point above 75°C, unexpectedly, the lubricant's smoke performance is significantly improved, with significantly lower smoke volume and concentration at high temperatures. The first antioxidant content in the lubricant of the present invention can be 1.0% to 15.0% by weight, 1.0% to 12.0% by weight, 1.0% to 10.0% by weight, 1.2% to 10.0% by weight, 1.5% to 10.0% by weight, 2.0% to 10.0% by weight, 2.0% to 8.0% by weight, 2.0% to 6.0% by weight, 2.0% to 5.0% by weight, 2.5% to 5.0% by weight, 3.0% to 5.0% by weight, or a range between any two of the foregoing values, based on the weight of the lubricant.

[0044] The first antioxidant may be solid.

[0045] In some embodiments, the melting point of the first antioxidant is higher than 76°C, higher than 77°C, higher than 78°C, higher than 80°C, higher than 85°C, or higher than 90°C. In some embodiments, the melting point of the first antioxidant is no higher than 300°C, no higher than 280°C, no higher than 250°C, no higher than 220°C, no higher than 200°C, no higher than 180°C, no higher than 170°C, or no higher than 165°C. In some embodiments, the first antioxidant has a melting point of 76°C to 300°C, 77°C to 280°C, 78°C to 250°C, 80°C to 250°C, 80°C to 220°C, 80°C to 200°C, 80°C to 180°C, 80°C to 165°C, or a range between any two of the foregoing values. This can help effectively reduce the amount and concentration of smoke in the lubricant.

[0046] The first antioxidant may include any suitable type of antioxidant.

[0047] In some embodiments, the first antioxidant includes at least one first amine antioxidant. The first amine antioxidant may be an amine antioxidant having a melting point higher than 75°C.

[0048] Unless otherwise specified, the term "at least" before a number in this application means greater than or equal to. For example, at least one may include one, two, three...

[0049] In some embodiments, the first antioxidant includes at least one first amine antioxidant and at least one first phenolic antioxidant. The first phenolic antioxidant may be a phenolic antioxidant having a melting point higher than 75°C.

[0050] The experimental examples described below demonstrate that lubricants containing at least one first aminic antioxidant and at least one first phenolic antioxidant exhibit better smoke reduction performance than lubricants without the first phenolic antioxidant, generating less smoke and lower concentrations at high temperatures. This demonstrates that the first aminic antioxidant and the first phenolic antioxidant can produce a synergistic effect, resulting in even greater smoke reduction.

[0051] The first antioxidant may include any suitable amount of the first phenolic antioxidant.

[0052] In some embodiments, the first antioxidant comprises 1.0 wt % to 10.0 wt %, 1.0 wt % to 8.0 wt %, 1.0 wt % to 6.0 wt %, 1.0 wt % to 5.0 wt %, 1.0 wt % to 3.0 wt %, or 1.0 wt % to 2.0 wt %, or a range between any two of the foregoing values, based on the weight of the lubricant. In some embodiments, the first antioxidant may be substantially free of the first phenolic antioxidant.

[0053] The first antioxidant may include any suitable amount of the first aminic antioxidant.

[0054] In some embodiments, the antioxidant includes 1.0 wt % to 15.0 wt %, 1.0 wt % to 12.0 wt %, 1.0 wt % to 10.0 wt %, 1.0 wt % to 8.0 wt %, 1.0 wt % to 6.0 wt %, 1.0 wt % to 5.0 wt %, or 1.0 wt % to 4.0 wt %, or a range between any two of the foregoing values, of the first amine antioxidant, based on the weight of the lubricant.

[0055] The first antioxidant may include any suitable amount of the first aminic antioxidant and the first phenolic antioxidant.

[0056] In some embodiments, the content of the first amine antioxidant is greater than that of the first phenolic antioxidant.

[0057] Experimental examples show that compared with lubricants in which the content of the first amine antioxidant is greater than that of the first phenolic antioxidant, lubricants in which the content of the first amine antioxidant is not greater than that of the first phenolic antioxidant have better smoke performance, less smoke volume and lower concentration at high temperatures.

[0058] In some embodiments, the antioxidant includes a second antioxidant having a melting point not higher than 75° C. The second antioxidant may be an antioxidant having a melting point not higher than 75° C.

[0059] In some embodiments, the antioxidant is substantially free of a second antioxidant having a melting point of no higher than 75°C.

[0060] Unless otherwise specified, "substantially free of," "substantially free of," and similar terms herein may mean: a content of 0, a content so low as to be undetectable, or a content lower than or equal to a specific value, etc. The specific value may be a content value that does not affect the performance or state of the lubricant, such as 0.1 wt % based on the weight of the lubricant.

[0061] Depending on whether the second antioxidant and / or other antioxidants are contained, the weight of the antioxidant may be the weight of the first antioxidant, or the sum of the weights of the first antioxidant and the second antioxidant and / or other antioxidants.

[0062] In some embodiments, the weight of the antioxidant is 1.0 wt % to 25.0 wt %, 1.0 wt % to 20.0 wt %, 1.0 wt % to 15.0 wt %, 1.0 wt % to 12.0 wt %, 1.5 wt % to 10.0 wt %, 2.0 wt % to 10.0 wt %, 2.0 wt % to 8.0 wt %, 2.0 wt % to 6.0 wt %, 2.0 wt % to 5.0 wt %, 2.5 wt % to 5.0 wt %, 3.0 wt % to 8.0 wt %, or a range between any two of the foregoing values, based on the weight of the lubricant.

[0063] In some embodiments, the antioxidant is selected from the following: N-phenyl-N'-isopropyl-p-phenylenediamine, N,N'-di(1,4-dimethylpentyl)-p-phenylenediamine, N-phenyl-N'-(p-toluenesulfonyl)-p-phenylenediamine, monononyldiphenylamine, dinonyldiphenylamine, trinonyldiphenylamine, butyloctyl-diphenylamine, 4,4'-di(phenylisopropyl)diphenylamine, 4,4'-diheptyldiphenylamine, 4,4'-dioctyldiphenylamine, α-naphthylamine, N-phenyl-α-naphthylamine, N-phenyl-1,1,3,3-tetramethylbutyl-α-naphthylamine, N-butylphenyl-α-naphthylamine, N-pentylphenyl-α-naphthylamine, N-hexyl 4-Heptylphenyl-α-naphthylamine, N-octylphenyl-α-naphthylamine, N-nonylphenyl-α-naphthylamine, N-dodecylphenyl-α-naphthylamine, 4,4′-thiobis(5-methyl-2-tert-butylphenol), diethylenethiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylate, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2-propionic acid, 3-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-1,6-hexanediol, octadecyl 3-(3′,5′-di-tert-butyl-4′-hydroxyphenyl)propionate.

[0064] The first amine antioxidant may include p-phenylenediamine compounds, mono- / poly-alkyldiphenylamine compounds, and naphthylamine compounds.

[0065] In some embodiments, the first amine antioxidant includes at least one selected from the following: 4,4'-dioctyldiphenylamine, 4,4'-bis-(α,α-dimethylbenzyl)diphenylamine, N-phenyl-N'-(p-toluenesulfonyl)-p-phenylenediamine, N-(4-tert-butylphenyl-α-naphthylamine), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine, 4,4'-bis-(phenylisopropyl)diphenylamine, and 4,4'-diheptyldiphenylamine. The first amine antioxidant may include one, two, or three selected from the aforementioned...

[0066] The first phenolic antioxidant may be a high molecular weight phenol including a thioether group or other groups.

[0067] In some embodiments, the first phenolic antioxidant includes at least one selected from the following: pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 4,4'-thiobis(5-methyl-2-tert-butylphenol), 3-(3,5-di-tert-butyl-4-hydroxyphenyl) acrylate isooctyl ester, hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 2-propionic acid 3-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-1,6-hexanediol ester. The first phenolic antioxidant may include one, two, or three selected from the aforementioned...

[0068] In an embodiment of the present invention, the aromatic ester-based material can be the base oil of the lubricant. The aromatic ester-based material has excellent high and low temperature performance, a low high temperature evaporation rate, low carbon deposition, and good compatibility with other components of the lubricant.

[0069] In some embodiments, the aromatic ester-based material is an aromatic ester of formula (I):

[0070] wherein R1 is a straight or branched chain alkyl group having 8 to 14 carbon atoms, and n is 3 or 4.

[0071] In some embodiments, the aromatic ester-based material is selected from esters of trimellitic acid, pyromellitic acid, trimellitic acid, and hemipyromellitic acid, wherein R1 is a linear or branched alkyl group having 8 to 12 carbon atoms. The aromatic ester-based material can be selected from trimellitic acid ester, pyromellitic acid ester, trimellitic acid ester, and hemipyromellitic acid ester.

[0072] In some embodiments, the aromatic ester-based material comprises trimellitate with a molecular weight of 500 g / mol to 1500 g / mol. Trimellitate with different molecular weights can correspond to different lubricant viscosity grades.

[0073] In some embodiments, the aromatic ester-based material is present in an amount of 55% to 85% by weight, 55% to 75% by weight, 55% to 70% by weight, 56% to 67% by weight, 60% to 65% by weight, or any range between any two of the foregoing values, based on the weight of the lubricant. Different weight percentages of the aromatic ester-based material correspond to different lubricant viscosity grades.

[0074] In the embodiment of the present invention, the polyisobutylene can be both the base oil of the lubricant and the viscosity enhancer of the lubricant. The polyisobutylene can hardly generate carbon deposits under high temperature conditions, but has a tendency to decompose.

[0075] In some embodiments, the polyisobutylene is an unhydrogenated homopolymer having a number average molecular weight of 1000 g / mol to 3000 g / mol. Polyisobutylenes of different molecular weights may correspond to different viscosity grades and viscosity indices of lubricants.

[0076] Choosing the right amount of polyisobutylene is crucial for preventing lubricant dripping. Using too much polyisobutylene can increase the viscosity of the lubricant at room temperature, making it difficult to use; using too little can reduce the lubricant film thickness, affecting adhesion properties.

[0077] In some embodiments, the polyisobutylene is present in an amount of 10 wt % to 45 wt %, 15 wt % to 45 wt %, 20 wt % to 45 wt %, 20 wt % to 35 wt %, 25 wt % to 35 wt %, 28 wt % to 35 wt %, 28 wt % to 33 wt %, 30 wt % to 35 wt %, 30 wt % to 33 wt %, or a range between any two of the foregoing values, based on the weight of the lubricant.

[0078] The extreme pressure anti-wear agent can prevent the metal surface from being worn, scratched or even sintered under the condition that the metal surface bears a load. The extreme pressure anti-wear agent can generally form a protective film with the metal surface under local high temperature and high pressure conditions.

[0079] The extreme pressure anti-wear agent may include at least one of triphenyl phosphate derivatives, triphenyl thiophosphate derivatives, dithiophosphate derivatives, amine-neutralized phosphates, and acidic phosphate amine salts.

[0080] The components of the extreme pressure anti-wear agent in a specific content combination can have a synergistic effect with each other and have good compatibility with other ingredients.

[0081] In some embodiments, the extreme pressure anti-wear agent is present in an amount of no more than 4.5% by weight, no more than 4.0% by weight, no more than 3.0% by weight, no more than 3.0% by weight, no more than 2.0% by weight, no more than 1.5% by weight, or no more than 1.0% by weight, based on the weight of the lubricant, such as 0.1% to 4.5% by weight, 0.1% to 4.0% by weight, 0.5% to 4.5% by weight, 0.5% to 4.0% by weight, 0.5% to 3.5% by weight, 0.5% to 1.5% by weight, or 0.5% to 1.0% by weight, or a range between any two of the foregoing values. This can help the lubricant have stronger load-bearing capacity and anti-wear capabilities.

[0082] In some embodiments, the extreme pressure anti-wear agent is selected from at least two or three of the following: alkylated triphenyl thiophosphate, a mixture of tert-butylphenyl phosphate, an amine-neutralized phosphate, a dithiophosphate derivative, a triphenyl phosphate derivative, a triphenyl thiophosphate derivative, and an acidic phosphate amine salt. This can contribute to the lubricant having a stronger load-bearing capacity and anti-wear capability.

[0083] In addition to the above components, the lubricant may include additives of any suitable type and dosage, such as 0.01% to 2.0% by weight, 0.01% to 1.0% by weight, 0.05% to 0.5% by weight, 0.05% to 0.3% by weight, 0.05% to 0.2% by weight, or an anti-corrosion agent in a range between any two of the aforementioned values, based on the weight of the lubricant. The anti-corrosion agent can form a firm adsorption film on the metal surface, isolating the metal surface from contact with water or oxygen in the air, destroying the conditions for electrochemical reactions, and thus preventing the occurrence of corrosion. The anti-corrosion agent may include benzotriazole derivatives. Benzotriazole derivatives can also be used as non-ferrous metal passivators, mainly used to form a protective film layer on the surface of non-ferrous metals such as copper, thereby protecting parts made of non-ferrous metals such as copper, and helping non-ferrous metals such as copper to resist corrosion.

[0084] In some embodiments, the lubricant is substantially free of Type I base oil, Type II base oil, Type III base oil, and / or poly-α-olefin, which can facilitate the application of the lubricant in relatively high temperature environments.

[0085] Type I base oil can also be called Group I base oil. Its sulfur content can be greater than 0.03%, the saturated hydrocarbon content can be less than 90%, and the viscosity index can be 80 to 120. It is mainly used in light load conditions with lower requirements.

[0086] Type II base oil can also be called Group II base oil. Its sulfur content can be less than 0.03%, the saturated hydrocarbon content can be greater than 90%, and the viscosity index can be 80 to 120. The performance, purity, color and oxidation resistance of Type I base oil are improved.

[0087] Type III base oil can also be called Group III base oil. Its sulfur content can be less than 0.03%, the saturated hydrocarbon content can be greater than 90%, and the viscosity index can be greater than 120. It has a higher viscosity than Group II base oil and can be used in situations with higher requirements. At the same time, pollutants are reduced.

[0088] Polyalphaolefin (PAO) is a synthetic base oil, often abbreviated as PAO. It can be made by polymerizing ethylene to form alpha olefins, followed by further polymerization and hydrogenation. If the alpha olefin is decene, it can be called polydecene; if the alpha olefin is dodecene, it can be called polydodecene. Polyalphaolefins can also be mixed polymers of decene and dodecene.

[0089] The lubricant of the embodiment of the present invention meets various main indicators of a lubricant and has excellent smoke performance.

[0090] The smoke performance test of the lubricant in the embodiment of the present application can be performed using a TSI smoke tester and an oven at a temperature of 240°C. The cumulative smoke volume in the first 120 minutes is obtained by integrating the area of ​​the curve of the concentration of particulate matter (PM10) with a particle size of less than 10 microns versus time, and the peak PM10 concentration is observed.

[0091] In some embodiments, the lubricant has at least one of the following properties: a) the cumulative smoke volume in the first 120 minutes is less than 25g / m 3 , less than 23g / m 3 , less than 21g / m 3 , or less than 20g / m 3 ; b) PM10 concentration peak is lower than 500mg / m 3 , less than 450mg / m 3 , less than 400mg / m 3 , less than 350mg / m 3 , or less than 300mg / m 3 c) a kinematic viscosity at 40°C of at least 100 mm2 as measured by ASTM D445; 2 / s, at least 200mm 2 / s, at least 220mm 2 / s, or at least 260mm 2 / s, for example 220mm 2 / s~460mm 2 / s, 260mm 2 / s~460mm 2 / s, or 260mm 2 / s~320mm 2 / s; d) a viscosity index of at least 115, at least 118, at least 119, or at least 120 as measured according to ASTM D 2270; e) a flash point of at least 280°C, at least 282°C, at least 285°C, at least 288°C, or at least 290°C; and f) an evaporation loss rate of about 50%, 40%, 35%, 30%, 25%, 20%, or less when measured after evaporation at 230°C for 72 hours.

[0092] Another aspect of an embodiment of the present invention relates to a lubricant comprising: (I) 55.0 to 70 wt % of an aromatic ester-based material, based on the weight of the lubricant; (II) 28.0 to 35.0 wt % of polyisobutylene, based on the weight of the lubricant; (III) 3.0 to 8.0 wt % of an antioxidant, based on the weight of the lubricant, the antioxidant comprising a first antioxidant having a melting point greater than 75° C.; the first antioxidant comprising at least one first aminic antioxidant and optionally at least one first phenolic antioxidant, and the content of the first aminic antioxidant is greater than or equal to the first phenolic antioxidant; and (IV) no more than 4.5 wt % of an extreme pressure anti-wear agent, based on the weight of the lubricant.

[0093] The relevant descriptions of the lubricant, the aromatic ester-based material, the polyisobutylene, the antioxidant, the first antioxidant, the first amine antioxidant, the first phenolic antioxidant, and the extreme pressure anti-wear agent can be referred to above and will not be repeated here.

[0094] Experimental examples show that a lubricant comprising at least one first amine antioxidant having a melting point exceeding 75°C and optionally at least one first phenolic antioxidant having a melting point exceeding 75°C, and wherein the content of the first amine antioxidant is greater than or equal to the content of the first phenolic antioxidant, correspondingly exhibits better smoke performance than lubricant samples comprising less first amine antioxidant than the first phenolic antioxidant, containing no first phenolic antioxidant, or containing no first antioxidant having a melting point exceeding 75°C, and generates less smoke and lower concentration at high temperatures.

[0095] The lubricant described in the present application can be used in scenarios with relatively high temperatures, such as 200° C. to 250° C., and with relatively high requirements for smoke performance.

[0096] Yet another aspect of an embodiment of the present invention relates to the use of the lubricant as described herein for lubricating a chain, chain rollers or belt of a continuous press at a temperature of 200°C to 250°C.

[0097] The continuous press can be a continuous automatic press, which can be equipped with a continuous automatic feeding robot, which can send the workpiece to the next station in sequence with the help of the movement of the chain, chain roller or belt, so that multi-process high-speed production can be carried out.

[0098] The lubricant described in this application can lubricate, assist in cooling, prevent rust, clean, seal, and buffer the chains, chain rollers, or belts of a continuous press, and can reduce friction and wear of the chains, chain rollers, or belts to protect the chains, chain rollers, or belts.

[0099] The continuous press can be used in stentering machines, wood processing, automobile coating lines, food baking, canning industries, etc.

[0100] Another aspect of an embodiment of the present invention relates to a method for preparing a lubricant as described in the present application, comprising the following steps: A) mixing the aromatic ester-based material, the polyisobutylene, the antioxidant, and the extreme pressure anti-wear agent; and B) stirring at a temperature not lower than the melting point of the first antioxidant for at least 30 minutes to obtain the lubricant.

[0101] The preparation method involved in the present application fully dissolves each component in the base oil and mixes the entire lubricant system evenly through sufficient stirring. The operation is simple, the cost is low, and the obtained lubricant has excellent performance.

[0102] In some embodiments, the temperature not lower than the melting point of the first antioxidant is 80-165°C.

[0103] The following experimental examples may be used to help understand the embodiments of the present invention and are not intended to be used as limitations on the claims.

[0104] Experimental Example

[0105] Trimellitate, polyisobutylene, an amine antioxidant, a phenolic antioxidant, an extreme pressure anti-wear agent, and an anti-corrosion agent were mixed according to the corresponding weight percentages shown in Table 1 below for Comparative Example 1 and Examples 1-5, and stirred at a constant temperature of not less than the melting point of the amine antioxidant and the phenolic antioxidant (e.g., 80-165°C) for 30 minutes to obtain the lubricants of Comparative Example 1 and Examples 1-5. The composition of a commercially available brand of high-temperature chain lubricant used as Comparative Example 2 and the melting points of the solid antioxidants are listed in Table 1 below.

[0106] Table 1

[0107] The trimellitate, polyisobutylene, amine antioxidant, phenolic antioxidant, extreme pressure anti-wear agent, and corrosion inhibitor used in Comparative Example 1 and Examples 1-5 were all commercially available products. The molecular weight of the trimellitate was 1177.72 g / mol. Polyisobutylene was an unhydrogenated homopolymer with a number average molecular weight (Mn) of 1300 g / mol and a polydispersity index (Polydispersity Index) of 1.65, obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn).

[0108] The observed color and performance results of the lubricant samples of Examples 1-5 and Comparative Examples 1-2 are listed in Table 2 below.

[0109] Table 2

[0110] The flash point, kinematic viscosity at 40°C, and viscosity index of each lubricant sample were tested according to the national standards for lubricant testing described below: ASTM D 92, ASTM D445, and ASTM D 2270, respectively.

[0111] The friction coefficient of each lubricant sample was tested according to the German Institute for Standardization standard DIN51834. The test conditions included: ball / disc, load 250N, temperature: 50-250°C, 1mm, 50Hz.

[0112] In the high-temperature experiment, a 5-gram lubricant sample was placed in a closed aluminum pan and heated at 230°C for 72 hours to evaporate. The remaining sample was weighed to calculate the evaporation loss rate. The shear viscosity of the remaining sample was then measured using an Anton Paar Physica MCR 302 rheometer at D = 300 / s and T = 25°C according to DIN 51810-1.

[0113] The coking performance of each lubricant sample was tested using the interval lubrication method used for chain lubrication using a Brückner central lubrication system. Specifically, at a high temperature of 240°C, the lubricant sample was dripped onto a standard 316L steel plate tilted at a 34° angle at fixed intervals, controlled by an external peristaltic pump, for a 48-hour test period. After the test, the mass change of the test plate was measured, and the coking performance of each lubricant sample was evaluated based on the surface appearance of the test plate.

[0114] In the carbon deposit solubility test, a certain mass of lubricant sample is placed in a curved steel plate and baked in an oven at 250°C for 72 hours to volatilize and decompose the lubricant sample, rendering it non-fluid. The remaining carbon deposit in the plate appears to be powdery or semi-lacquer-like. The same mass of carbon deposit is then dispersed in the same volume of fresh, unbaked lubricant sample and stirred to dissolve. The solubility percentage of each lubricant sample is then calculated based on the amount of soluble carbon deposit.

[0115] Smoke tests on each lubricant sample were conducted using a TSI smoke tester and oven at 240°C. The concentration data for particulate matter (PM10) below 10 microns, obtained over 360 minutes, is shown in Figure 1. The cumulative smoke volume (integrated area) and peak PM10 concentration for the first 120 minutes of testing are listed in Table 2 above.

[0116] Referring to Table 2, it can be seen that the color of the lubricant samples of Examples 1-5 of the present invention is the same or similar to that of the commercially available product sample of Comparative Example 2, and the flash point is over 280°C, with good high temperature resistance, which can meet the temperature requirements of different market applications.

[0117] The lubricant samples of Examples 1-5 of the present invention were comparable to, better than, or acceptable to the lubricant samples of Comparative Examples 1-2 in terms of viscosity, friction coefficient, etc.

[0118] The evaporation loss rate of the lubricant samples of Examples 1-5 of the present invention is significantly lower than that of Comparative Examples 1-2, which can reduce lubricant consumption, extend the lubrication cycle, reduce smoke generation, reduce pollution to the environment and harm to the health of on-site operators, and also save oil costs for users.

[0119] The coking performance and carbon deposit solubility of the lubricant samples of Examples 1-5 of the present invention are at least acceptable, which can reduce the probability of failure of the lubricated components during operation, thereby reducing the cost of downtime maintenance and ensuring long-term stable operation of the equipment.

[0120] As can be seen from Table 2 and Figure 1, compared with Comparative Examples 1-2 which do not contain a first antioxidant with a melting point higher than 75°C, Examples 1-5 of the present invention which contain at least one first antioxidant with a melting point higher than 75°C have better smoke performance, and their cumulative smoke volume and PM10 concentration peak data in the first 120 minutes are significantly lower.

[0121] As shown in Figure 1, the smoke generated by the lubricant samples of Examples 1-5 and the lubricant samples of Comparative Examples 1-2 is generally more in the first 30 minutes, most of which can reach a peak, and generally tend to gradually decrease with time. The peak PM10 concentrations generated by the lubricant samples of Examples 1-5 are significantly lower than those of the comparative samples, and the cumulative amount of smoke generated by the lubricant samples of Examples 1-5 in the first 120 minutes is also significantly lower than that of the lubricant samples of Comparative Examples 1 and 2. The smoke performance of the lubricant samples of Examples 1-5 is improved by about 100% compared with the lubricant samples of the commercially available products in Comparative Example 2.

[0122] Comparing Example 2 of the present invention with Comparative Example 2, it can be found that when the first antioxidant having a melting point exceeding 75° C. is contained, unexpectedly, the smoke performance of the lubricant is significantly improved.

[0123] Furthermore, the lubricant samples of Examples 3-5 of the present invention contain at least one first amine antioxidant having a melting point exceeding 75°C and at least one first phenolic antioxidant having a melting point exceeding 75°C, and the content of the first amine antioxidant is at least 2 weight % and greater than the content of the first phenolic antioxidant. Accordingly, they exhibit better smoke performance than the lubricant samples of Examples 1 and 2 of the present invention, which contain no more first amine antioxidant than the first phenolic antioxidant or do not contain a first phenolic antioxidant.

[0124] It can be seen from the above experimental examples that the present invention can be beneficial in meeting the main properties of the lubricant at a lower cost, while emitting less smoke at high temperatures, causing less pollution to the environment, and meeting higher environmental protection requirements.

[0125] Those skilled in the art will appreciate that the embodiments of the present invention include the following technical solutions:

[0126] 1. A lubricant comprising:

[0127] (i) at least 45.0 wt. % of an aromatic ester-based material, based on the weight of the lubricant;

[0128] (ii) 10.0 wt. % to 45.0 wt. % of polyisobutylene, based on the weight of the lubricant;

[0129] (iii) an antioxidant comprising 1.0 wt% to 15.0 wt% of a first antioxidant having a melting point above 75°C, based on the weight of the lubricant; and

[0130] (iv) not more than 4.5 wt. % of an extreme pressure antiwear agent, based on the weight of the lubricant.

[0131] 2. In the lubricant according to technical solution 1, the first antioxidant has a melting point of 80°C to 165°C.

[0132] 3. In the lubricant according to technical solution 1 or 2, the first antioxidant comprises at least one first amine antioxidant.

[0133] 4. In the lubricant according to any one of technical solutions 1 to 3, the first antioxidant comprises at least one first amine antioxidant and at least one first phenolic antioxidant.

[0134] 5. In the lubricant according to any one of technical solutions 1 to 4, the first antioxidant comprises 1.0 wt % to 3.0 wt % of the first phenolic antioxidant based on the weight of the lubricant.

[0135] 6. In the lubricant according to any one of technical solutions 1 to 5, the content of the first amine antioxidant is greater than that of the first phenolic antioxidant.

[0136] 7. In the lubricant according to any one of technical solutions 1 to 6, the antioxidant comprises 1.0 wt % to 8.0 wt % of the first amine antioxidant based on the weight of the lubricant.

[0137] 8. In the lubricant according to any one of technical solutions 1 to 7, the antioxidant comprises a second antioxidant having a melting point not higher than 75°C.

[0138] 9. In the lubricant according to any one of technical solutions 1 to 8, the antioxidant substantially does not contain a second antioxidant having a melting point not higher than 75°C.

[0139] 10. The lubricant according to any one of technical solutions 1 to 9, wherein the weight of the antioxidant is 3.0 wt% to 8.0 wt% based on the weight of the lubricant.

[0140] 11. In the lubricant according to any one of technical solutions 1 to 10, the first amine antioxidant comprises at least one selected from the group consisting of: 4,4'-dioctyldiphenylamine, 4,4'-di-(α,α-dimethylbenzyl)diphenylamine, N-phenyl-N'-(p-toluenesulfonyl)-p-phenylenediamine, N-(4-tert-butylphenyl-α-naphthylamine), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine, 4,4'-bis-(phenylisopropyl)diphenylamine, and 4,4'-diheptyldiphenylamine.

[0141] 12. In the lubricant according to any one of technical solutions 1 to 11, the first phenolic antioxidant comprises at least one selected from the group consisting of pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 4,4'-thiobis(5-methyl-2-tert-butylphenol), isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylate, hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 3-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-1,6-hexanediol 2-propionate.

[0142] 13. The lubricant according to any one of technical solutions 1 to 12, wherein the aromatic ester-based material is an aromatic ester of the general formula (I):

[0143] wherein R1 is a straight or branched chain alkyl group having 8 to 14 carbon atoms, and n is 3 or 4.

[0144] 14. A lubricant as described in any one of technical solutions 1 to 13, wherein the aromatic ester-based material is selected from esters of trimellitic acid, pyromellitic acid, trimellitic acid, and hemipyromellitic acid, wherein R1 is a straight-chain or branched alkyl group having 8 to 12 carbon atoms.

[0145] 15. The lubricant according to any one of technical solutions 1 to 14, wherein the aromatic ester-based material comprises a trimellitic acid ester having a molecular weight of 500 to 1500 g / mol.

[0146] 16. The lubricant according to any one of technical solutions 1 to 15, wherein the aromatic ester-based material accounts for 55 to 85 weight % based on the weight of the lubricant.

[0147] 17. The lubricant according to any one of technical solutions 1 to 16, wherein the polyisobutylene is an unhydrogenated homopolymer having a number average molecular weight of 1000 g / mol to 3000 g / mol.

[0148] 18. The lubricant according to any one of technical solutions 1 to 17, wherein the polyisobutylene is present in an amount of 28% to 35% by weight based on the weight of the lubricant.

[0149] 19. The lubricant according to any one of technical solutions 1 to 18, wherein the extreme pressure anti-wear agent is present in an amount of 0.1 wt % to 3.5 wt % based on the weight of the lubricant.

[0150] 20. A lubricant as described in any one of technical solutions 1 to 19, wherein the extreme pressure anti-wear agent is selected from at least two or three of the following: alkylated triphenyl thiophosphate, a mixture of tert-butylphenyl phosphate, an amine-neutralized phosphate, a dithiophosphate derivative, a triphenyl phosphate derivative, a triphenyl thiophosphate derivative, and an acidic phosphate amine salt.

[0151] 21. The lubricant according to any one of technical solutions 1 to 20, which is substantially free of Type I, Type II and Type III base oils and / or poly-α-olefins.

[0152] 22. The lubricant according to any one of technical solutions 1 to 21, having at least one of the following properties:

[0153] a) The cumulative smoke volume in the first 120 minutes is less than 25g / m 3 ;

[0154] b) The peak concentration of PM10 is lower than 500 mg / m 3 , or less than 350mg / m 3 ;

[0155] c) a kinematic viscosity at 40°C of at least 100 mm2 as measured according to ASTM D445 2 / s;

[0156] d) a viscosity index of at least 115 as measured according to ASTM D 2270;

[0157] e) a flash point of at least 280°C; and

[0158] f) The evaporation loss rate measured after evaporation at 230°C for 72 hours is about 50% or less.

[0159] 23. A lubricant comprising:

[0160] (I) 55.0 wt. % to 70 wt. % of an aromatic ester-based material, based on the weight of the lubricant;

[0161] (II) 28.0 wt. % to 35.0 wt. % of polyisobutylene, based on the weight of the lubricant;

[0162] (III) 3.0 wt% to 8.0 wt% of an antioxidant, based on the weight of the lubricant, the antioxidant comprising a first antioxidant having a melting point greater than 75°C; the first antioxidant comprising at least one first aminic antioxidant and optionally at least one first phenolic antioxidant, and the content of the first aminic antioxidant is greater than or equal to the content of the first phenolic antioxidant; and

[0163] (IV) Not more than 4.5 wt. % of an extreme pressure antiwear agent, based on the weight of the lubricant.

[0164] 24. Use of the lubricant of any one of technical solutions 1 to 23 in lubricating the chain, chain rollers or belts of a continuous press at a temperature of 200°C to 250°C.

[0165] 25. A method for preparing the lubricant according to any one of technical solutions 1 to 23, comprising the following steps:

[0166] A) mixing the aromatic ester-based material, the polyisobutylene, the antioxidant, and the extreme pressure antiwear agent; and

[0167] B) stirring at a temperature not lower than the melting point of the first antioxidant for at least 30 minutes to obtain the lubricant.

[0168] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A lubricant, characterized in that: include: (v) at least 45.0 wt. % of an aromatic ester-based material, based on the weight of the lubricant; (vi) 10.0 wt % to 45.0 wt % of polyisobutylene, based on the weight of the lubricant; (vii) an antioxidant comprising 1.0 wt % to 15.0 wt % of a first antioxidant having a melting point above 75° C., based on the weight of the lubricant; as well as (viii) not more than 4.5 wt. % of an extreme pressure antiwear agent, based on the weight of the lubricant.

2. The lubricant according to claim 1, characterized in that The first antioxidant has a melting point of 80°C to 165°C.

3. The lubricant according to claim 1, characterized in that The first antioxidant comprises at least one first amine antioxidant.

4. The lubricant according to claim 1, characterized in that The first antioxidant includes at least one first amine antioxidant and at least one first phenolic antioxidant.

5. The lubricant according to claim 4, characterized in that The first antioxidant includes 1.0 wt % to 3.0 wt % of the first phenolic antioxidant based on the weight of the lubricant.

6. The lubricant according to claim 4, characterized in that The content of the first amine antioxidant is greater than that of the first phenol antioxidant.

7. The lubricant according to any one of claims 3 to 6, characterized in that The antioxidant includes 1.0 wt % to 8.0 wt % of the first amine antioxidant based on the weight of the lubricant.

8. The lubricant according to claim 1, characterized in that The antioxidant includes a second antioxidant having a melting point not higher than 75°C.

9. The lubricant according to claim 1, characterized in that The antioxidant substantially does not contain a second antioxidant having a melting point of not higher than 75°C.

10. The lubricant according to claim 1, 8 or 9, characterized in that The weight of the antioxidant is 3.0 wt % to 8.0 wt % based on the weight of the lubricant.

11. The lubricant according to claim 3 or 4, characterized in that The first amine antioxidant includes at least one selected from the following: 4,4'-dioctyldiphenylamine, 4,4'-di-(α,α-dimethylbenzyl)diphenylamine, N-phenyl-N'-(p-toluenesulfonyl)-p-phenylenediamine, N-(4-tert-butylphenyl-α-naphthylamine), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine, 4,4'-bis-(phenylisopropyl)diphenylamine, and 4,4'-diheptyldiphenylamine.

12. The lubricant according to claim 4, characterized in that The first phenolic antioxidant includes at least one selected from the following: pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 4,4'-thiobis(5-methyl-2-tert-butylphenol), 3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylate isooctyl ester, hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 2-propionic acid 3-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-1,6-hexanediol ester.

13. The lubricant according to claim 1, characterized in that The aromatic ester-based material is an aromatic ester of the general formula (I): wherein R1 is a straight or branched chain alkyl group having 8 to 14 carbon atoms, and n is 3 or 4.

14. The lubricant according to claim 13, characterized in that The aromatic ester-based material is selected from esters of trimellitic acid, pyromellitic acid, trimellitic acid, and hemipyromellitic acid, wherein R1 is a straight or branched chain alkyl group having 8 to 12 carbon atoms.

15. The lubricant according to claim 1, characterized in that The aromatic ester-based material includes trimellitic acid esters having a molecular weight of 500 to 1500 g / mole.

16. The lubricant according to claim 1, characterized in that The aromatic ester-based material is 55 to 85 weight percent based on the weight of the lubricant.

17. The lubricant according to claim 1, characterized in that The polyisobutylene is an unhydrogenated homopolymer having a number average molecular weight of 1000 to 3000 g / mol.

18. The lubricant according to claim 1, characterized in that The polyisobutylene is 28 to 35 wt % based on the weight of the lubricant.

19. The lubricant according to claim 1, characterized in that The extreme pressure anti-wear agent is present in an amount of 0.1 to 3.5 wt % based on the weight of the lubricant.

20. The lubricant according to claim 19, characterized in that The extreme pressure anti-wear agent is selected from at least two or three of the following: alkylated triphenyl thiophosphate, a mixture of tert-butylphenyl phosphate, amine-neutralized phosphate, dithiophosphate derivatives, triphenyl phosphate derivatives, triphenyl thiophosphate derivatives, and acidic phosphate amine salts.

21. The lubricant according to claim 1, characterized in that Essentially free of Type I, Type II and Type III base oils and / or polyalphaolefins.

22. The lubricant according to claim 1, characterized in that Having at least one of the following properties: g) The cumulative smoke volume in the first 120 minutes is less than 25g / m 3 ; h) The peak concentration of PM10 is lower than 500 mg / m 3 , or less than 350mg / m 3 ; i) a kinematic viscosity at 40°C of at least 100 mm 2 / s; j) a viscosity index of at least 115 as measured according to ASTM D 2270; k) a flash point of at least 280°C; and l) The evaporation loss rate measured after evaporation at 230°C for 72 hours is about 50% or less.

23. A lubricant, characterized in that: include: (I) 55.0 wt % to 70 wt % of an aromatic ester-based material, based on the weight of the lubricant; (II) 28.0 wt % to 35.0 wt % of polyisobutylene, based on the weight of the lubricant; (III) 3.0 wt % to 8.0 wt % of an antioxidant based on the weight of the lubricant, the antioxidant comprising a first antioxidant having a melting point greater than 75° C.; the first antioxidant comprising at least one first amine antioxidant and optionally at least one first phenolic antioxidant, and the content of the first amine antioxidant is greater than or equal to the first phenolic antioxidant; and (IV) Not more than 4.5 wt. % of an extreme pressure antiwear agent, based on the weight of the lubricant.

24. Use of a lubricant according to any one of claims 1 to 23 for lubricating chains, chain rollers or belts of a continuous press at temperatures of 200°C to 250°C.

25. A method for preparing a lubricant according to any one of claims 1 to 23, characterized in that: The following steps are involved: A) mixing the aromatic ester-based material, the polyisobutylene, the antioxidant, and the extreme pressure antiwear agent; and B) stirring at a temperature not lower than the melting point of the first antioxidant for at least 30 minutes to obtain the lubricant.

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