JP2021147620A - Low viscosity lubricating oil composition - Google Patents

Abstract

To overcome the disadvantage of low-viscosity lubricating oils that they can have high volatility leading to high evaporation loss (i.e. increased oil consumption).SOLUTION: The invention generally relates to lubricating oil compositions useful for reducing NOACK volatility in finished lubricating oils of an internal combustion engine. Also disclosed is a method for reducing NOACK volatility in finished lubricating oils in the engine.SELECTED DRAWING: None

Description

The lubricant industry is actively involved in research related to improving fuel economy. One of the well-known methods for improving fuel efficiency is to reduce the viscosity of the lubricating oil. Engine oils that exhibit excellent fuel economy performance are usually prepared to be low viscosity oils. Viscosity index improvers (VII) are often used to reduce fluid friction due to viscous resistance at low temperatures. The disadvantage of low viscosity engine oils is that they can have high volatility (ie, increased oil consumption) leading to high evaporation losses.

Attempts to overcome the above problems include formulations with low volatility base oils such as esters and poly-α-olefins. However, these low volatility base oils may not be suitable for low viscosity engine oils such as 0W-12, 0W-8 and 0W-4.

の構造のうちの１つを有するジエステルを含む基油であって、各Ｒは独立してＣ_１〜Ｃ_２０の飽和または不飽和アルキル基であり、ｎは１〜８の整数であり、前記ジエステルがＡＳＴＭ Ｄ４４５に準拠した１００℃における動粘度が２．５〜３．５ｍｍ^２／ｓであり、ＡＳＴＭ Ｄ２２７０に準拠した粘度指数が１１０〜１７５であるものである、上記基油と、潤滑油組成物の総重量を基準として７５〜５００ｐｐｍのホウ素であって、１種以上のホウ素含有分散剤から提供される上記ホウ素と、を含む潤滑油組成物が提供される。 According to one embodiment of the present invention, the lubricating oil composition is described below.

A base oil containing a diester having one of the structures of, each R being an independently _{saturated or unsaturated alkyl group of C 1 to} C ₂₀ , where n is an integer of 1 to 8, said. The base oil and lubricating oil in which the diester has an ASTM D445 kinematic viscosity at 100 ° C. of 2.5 to 3.5 mm ² / s and an ASTM D2270 kinematic viscosity index of 110 to 175. Provided is a lubricating oil composition containing 75 to 500 ppm of boron based on the total weight of the composition and the above-mentioned boron provided from one or more boron-containing dispersants.

の構造のうちの１つを有するジエステルを含む基油であって、各Ｒは独立してＣ_１〜Ｃ_２０の飽和または不飽和アルキル基からなる群から選択され、ｎは１〜８の整数であり、前記ジエステルがＡＳＴＭ Ｄ４４５に準拠した１００℃における動粘度が２．５〜３．５ｍｍ^２／ｓであり、ＡＳＴＭ Ｄ２２７０に準拠した粘度指数が１１０〜１７５であるものである、上記基油と、潤滑油組成物の総重量を基準として７５〜５００ｐｐｍのホウ素であって、１種以上のホウ素含有分散剤から提供される上記ホウ素と、を含む潤滑油組成物を用いて上記エンジンを潤滑させることを含む方法が提供される。 According to another embodiment of the present invention, a method for reducing evaporation loss in an internal combustion engine is described below.

A base oil containing a diester having one of the structures of, each R is independently selected from the group consisting of saturated or unsaturated alkyl groups of _{C 1 to} C _{20, where n is an integer of 1 to 8.} The base oil has a kinematic viscosity of 2.5 to 3.5 mm ² / s at 100 ° C. according to ASTM D445 and a viscosity index of 110 to 175 according to ASTM D2270. Lubricating the engine with a lubricating oil composition containing 75 to 500 ppm of boron based on the total weight of the lubricating oil composition and the above-mentioned boron provided from one or more kinds of boron-containing dispersants. Methods are provided that include causing.

の構造のうちの１つを有するジエステルを含む基油であって、各Ｒは独立してＣ_１〜Ｃ_２０の飽和または不飽和アルキル基からなる群から選択され、ｎは１〜８の整数であり、前記ジエステルがＡＳＴＭ Ｄ４４５に準拠した１００℃における動粘度が２．５〜３．５ｍｍ^２／ｓであり、ＡＳＴＭ Ｄ２２７０に準拠した粘度指数が１１０〜１７５であるものである、上記基油と、潤滑油組成物の総重量を基準として７５〜５００ｐｐｍのホウ素であって、１種以上のホウ素含有分散剤から提供されるホウ素と、を含む潤滑油組成物を用いてエンジンを潤滑させることを含む方法が提供される。 According to yet another embodiment of the present invention, the method for improving the fuel efficiency of the engine is described below.

A base oil containing a diester having one of the structures of, each R is independently selected from the group consisting of saturated or unsaturated alkyl groups of _{C 1 to} C _{20, where n is an integer of 1 to 8.} The base oil has a kinematic viscosity of 2.5 to 3.5 mm ² / s at 100 ° C. according to ASTM D445 and a viscosity index of 110 to 175 according to ASTM D2270. Lubricating the engine with a lubricating oil composition containing 75 to 500 ppm of boron based on the total weight of the lubricating oil composition and boron provided by one or more boron-containing dispersants. Methods are provided that include.

Although there is room for various modifications and alternatives to this disclosure, those particular embodiments are described in detail herein. However, the description of a particular embodiment herein is not intended to be limited to the particular form disclosed, but rather falls within the spirit and scope of the disclosure as set forth in the appended claims. It should be understood that it is intended to cover all modifications, equivalents and alternatives.

To facilitate understanding of the subject matter disclosed herein, some terms, abbreviations or other abbreviations used herein are defined below. Any undefined term, abbreviation or abbreviation will be understood to have the usual meaning used by those skilled in the art contemporaneous with the filing of this application.

Definitions As used herein, the following terms have the following meanings, unless explicitly stated otherwise. As used herein, the following words and expressions have the following meanings as used.

By "major amount" is meant to exceed 50% by weight of the composition.

"Small amount" means less than 50% by weight of the composition and is used in the notation for the additives described and for the total mass of all additives present in the composition, one or more. Considered to be the active ingredient of the additive.

"Active ingredient" or "active substance" or "oil-free" means an additive material that is not a diluent or solvent.

All reported percentages are weight percent based on the active ingredient unless otherwise specified (ie, no oil for carrier or dilution is considered).

The abbreviation "ppm" means how much of a million parts by weight is based on the total weight of the lubricating oil composition.

High temperature high shear (HTHS) viscosity at 150 ° C. was determined according to ASTM D4683.

The kinematic viscosity at 100 ° C. (KV100) was determined according to ASTM D445.

Metals-The term "metal" means alkali metals, alkaline earth metals or mixtures thereof.

The term "oil-soluble" or "dispersible" means that the amount required to provide the desired activity or performance level can be incorporated by dissolving, dispersing or suspending in an oil having a lubricating viscosity. Used to indicate. Generally, this means that at least about 0.001% by weight of material can be incorporated into the lubricating oil composition. See US Pat. No. 4,320,019 for further study of terms, oil solubility and dispersibility, especially "stable dispersibility". The teachings in this regard herein are expressly incorporated herein by reference.

As used herein, the term "sulfate ash" means a non-flammable residue resulting from detergents and metal additives in lubricating oils. Sulfate ash content can be determined using ASTM test D874.

As used herein, the term "total base value" or "TBN" means the amount of base equivalent to milligrams of KOH in 1 gram of sample. Therefore, the higher the TBN number, the more alkaline products, i.e., the higher the alkalinity. TBN was determined using the ASTM D 2896 test.

The contents of boron, calcium, magnesium, molybdenum, phosphorus, sulfur and zinc were determined according to ASTM D5185.

Nitrogen content was determined according to ASTM D4629.

NOACK volatility was determined by either ASTM D5800A-D or ASTM D6417.

Unless otherwise specified, all percentages are weight percent.

Although there is room for various modifications and alternatives to this disclosure, those particular embodiments are described in detail herein. However, the description of a particular embodiment herein is not intended to be limited to the particular form disclosed, but rather falls within the spirit and scope of the disclosure as set forth in the appended claims. It should be understood that it is intended to cover all modifications, equivalents and alternatives.

Not all tasks described in the general description or examples are required, some specific tasks may not be required, and one or more subsequent tasks in addition to the tasks described. Please note that the work may be done. Moreover, the order in which the work is listed is not necessarily the order in which it is performed.

Benefits, other benefits and solutions to problems are described herein in relation to a particular embodiment. However, the benefits, other benefits, the solution to the problem, and one or more features that can lead to or become more prominent in the benefits, benefits, or solutions, are part or all of the claims. It should not be construed as an important feature, a required feature, or an essential feature of the range.

The details and examples of embodiments described herein are intended to provide a general understanding of the structure of the various embodiments.

As used in the present invention, the terms "comprises", "comprising", "includes", "inclusion", "has", "having". ) ”Or any other variant thereof is intended to cover non-exclusive inclusion. For example, a process, method, article or device that includes a list of features is not necessarily limited to those features alone, but other features that are not explicitly listed, or such steps, methods, articles. Alternatively, it may include other device-specific features. Moreover, unless explicitly stated otherwise, "or" means an inclusive OR rather than an exclusive OR. For example, the condition A or B is one of the following: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B Is true (or exists), and A and B are true (or exist).

The "a" or "an" is used to describe the elements and components described herein. This is done solely for convenience and to give a general meaning to the scope of the embodiments of the present disclosure. This description should be read as including one or at least one, and the singular may include plurals, and vice versa, unless otherwise apparent. The term "mean" is intended to mean mean, geometric mean or median when referring to a value. The group numbers corresponding to the columns in the periodic table of elements are the "New Notation" found in the CRC Handbook of Chemistry and Physics, 81st Edition (2000-2001). Is using the rules.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Materials, methods and examples are for illustrative purposes only and are not intended to be limiting. To the extent not described herein, many details regarding specific materials and processing practices are conventional and can be found in texts and other sources in the lubricant and oil and gas industries.

The specification and examples are intended to serve as a comprehensive and comprehensive description of all elements and features of formulations, compositions, devices and systems that use the structures or methods described herein. It's not something to do. Separate embodiments may be provided in combination with a single embodiment, and conversely, for brevity, the various features described in the context of a single embodiment may be provided separately or in any partial combination. May be provided at. In addition, when referring to the values listed in the range, each value and all values within that range are included. Many other embodiments may become apparent to those skilled in the art only after reading this specification. Other embodiments may be used and derived from the present disclosure so that structural substitutions, logical substitutions or other modifications can be made without departing from the scope of the disclosure. Therefore, this disclosure should be considered exemplary rather than limiting.

Lubricating oil compositions containing diester base oils and boronated dispersants have been found to result in lower NOACK volatility without increasing the viscosity of the oil. Due to this low volatility, the lubricating oil composition has a reduced evaporation loss as compared to other lubricating oil compositions prepared to have a low viscosity.

の構造ののうちの１つを有するジエステルを含む基油であって、各Ｒは独立してＣ_１〜Ｃ_２０の飽和または不飽和アルキル基からなる群から選択され、ｎは１〜８の整数であり、前記ジエステルがＡＳＴＭ Ｄ４４５に準拠した１００℃における動粘度が２．５〜３．５ｍｍ^２／ｓであり、ＡＳＴＭ Ｄ２２７０に準拠した粘度指数が１１０〜１７５であるものである、上記基油と、
ｂ．潤滑油組成物の総重量を基準として７５〜５００ｐｐｍのホウ素であって、１種以上のホウ素含有分散剤から提供される上記ホウ素と、を含む潤滑油組成物を提供する。 The present disclosure is a lubricating oil composition.
a. Less than,

A base oil containing a diester having one of the structures of, each R is independently selected from the group consisting of saturated or unsaturated alkyl groups of _{C 1 to} C _{20, where n is 1 to 8.} The above group, which is an integer, has a kinematic viscosity of 2.5 to 3.5 mm ² / s at 100 ° C. according to ASTM D445, and has a viscosity index of 110 to 175 according to ASTM D2270. With oil
b. Provided is a lubricating oil composition containing 75 to 500 ppm of boron based on the total weight of the lubricating oil composition, and the above-mentioned boron provided from one or more kinds of boron-containing dispersants.

の構造のうちの１つを有するジエステルを含む基油であって、各Ｒは独立してＣ_１〜Ｃ_２０の飽和または不飽和アルキル基からなる群から選択され、ｎは１〜８の整数であり、前記ジエステルがＡＳＴＭ Ｄ４４５に準拠した１００℃における動粘度が２．５〜３．５ｍｍ^２／ｓであり、ＡＳＴＭ Ｄ２２７０に準拠した粘度指数が１１０〜１７５であるものである、上記基油と、
ｂ．潤滑油組成物の総重量を基準として７５〜５００ｐｐｍのホウ素であって、１種以上のホウ素含有分散剤から提供される上記ホウ素と、を含む潤滑油組成物を用いて上記エンジンを潤滑させることを含む方法である。 Further disclosed are methods of reducing evaporation loss in an internal combustion engine or improving fuel efficiency.
a. Less than,

A base oil containing a diester having one of the structures of, each R is independently selected from the group consisting of saturated or unsaturated alkyl groups of _{C 1 to} C _{20, where n is an integer of 1 to 8.} The base oil has a kinematic viscosity of 2.5 to 3.5 mm ² / s at 100 ° C. according to ASTM D445 and a viscosity index of 110 to 175 according to ASTM D2270. When,
b. Lubricating the engine with a lubricating oil composition containing 75 to 500 ppm of boron based on the total weight of the lubricating oil composition and the above-mentioned boron provided from one or more kinds of boron-containing dispersants. It is a method including.

の構造のうちの１つを有するジエステルを含む基油であって、各Ｒは独立してＣ_１〜Ｃ_２０の飽和または不飽和アルキル基からなる群から選択され、ｎは１〜８の整数であり、前記ジエステルがＡＳＴＭ Ｄ４４５に準拠した１００℃における動粘度が２．５〜３．５ｍｍ^２／ｓであり、ＡＳＴＭ Ｄ２２７０に準拠した粘度指数が１１０〜１７５であるものである、上記基油と、
ｂ．潤滑油組成物の総重量を基準として７５〜５００ｐｐｍのホウ素であって、１種以上のホウ素含有分散剤から提供される上記ホウ素と、を含む使用も開示される。 Further, in order to reduce the evaporation loss in the internal combustion engine or to improve the fuel efficiency, the lubricating oil composition is used.
a. Less than,

A base oil containing a diester having one of the structures of, each R is independently selected from the group consisting of saturated or unsaturated alkyl groups of _{C 1 to} C _{20, where n is an integer of 1 to 8.} The base oil has a kinematic viscosity of 2.5 to 3.5 mm ² / s at 100 ° C. according to ASTM D445 and a viscosity index of 110 to 175 according to ASTM D2270. When,
b. Also disclosed are uses containing 75-500 ppm of boron relative to the total weight of the lubricating oil composition, the above-mentioned boron provided by one or more boron-containing dispersants.

The lubricating oil composition of the present invention contains synergistic constituents that maintain the low viscosity of the lubricating oil and at the same time reduce NOACK volatility. These components may be particularly useful in the preparation of lubricating oils that exhibit desirable properties, such as improved fuel efficiency in engines.

Base Oil In one aspect, the present disclosure provides one or more base oils. One or more base oils include one or more diester base oils and optionally additional base oils. The total amount of one or more base oils is about 50 to about 99% by weight based on the finished lubricant.

の構造のうちの１つを有し、各Ｒは独立してＣ_１〜Ｃ_２０の飽和または不飽和アルキル基からなる群から選択され、ｎは１〜８の整数である。一実施形態では、各Ｒは、独立してＣ_１〜Ｃ_１８の飽和または不飽和アルキル基からなる群から選択される。一実施形態では、各Ｒは、独立してＣ_１〜Ｃ_１６の飽和または不飽和アルキル基からなる群から選択される。一実施形態では、各Ｒは、独立してＣ_１〜Ｃ_１４の飽和または不飽和アルキル基からなる群から選択される。一実施形態では、各Ｒは、独立してＣ_１〜Ｃ_１２の飽和または不飽和アルキル基からなる群から選択される。 In one embodiment, the diester is:

Have one of the structures, each R is selected from the group consisting of saturated or unsaturated alkyl group of C ₁ -C ₂₀ independently, n represents an integer of 1 to 8. In one embodiment, each R is independently selected from the group consisting of saturated or unsaturated alkyl groups from _{C 1 to} C _18. In one embodiment, each R is independently selected from the group consisting of saturated or unsaturated alkyl groups from _{C 1 to} C _16. In one embodiment, each R is independently selected from the group consisting of saturated or unsaturated alkyl groups from _{C 1 to} C _14. In one embodiment, each R is independently selected from the group consisting of saturated or unsaturated alkyl groups from _{C 1 to} C _12.

In one embodiment, the present disclosure uses the diester base oil as a base oil from 5 to 99% by weight, 25 to 99% by weight, 50 to 99% by weight, 55 to 99% by weight, and 60 to 99% by weight based on the finished lubricant. , 65-99% by weight, 70-99% by weight, 75-99% by weight, 80-99% by weight.

Generally, diesters have a kinematic viscosity at 100 ° C. according to ASTM D445 of ^{2.5-3.5 mm 2 / s.}

Diesters typically have a viscosity index according to ASTM D2270 of 110-175. In one embodiment, the diester has a viscosity index according to ASTM D2270 of 125-175, 135-175.

Boron-containing dispersants Examples of boron-containing dispersants include boronized polyalkenyl succinic acid, nitrogen-free derivatives of polyalkylene anhydrous succinic acid, succinimide, carboxylic acid amides, hydrocarbyl monoamines, etc. Hydrocarbylpolyamines, Mannig bases, phosphonoamides, thiophosphonamides and phosphorus amides, thiazoles (eg, 2,5-dimercapto-1,3,4-thiasiazol, mercaptobenzothiazole and derivatives thereof), triazoles (eg alkyltriazoles and benzotriazoles). ), Carous acid esters and copolymers containing one or more additional polar functional groups such as amines, amides, imines, imides, hydroxys, carboxyls, etc. (eg, long chain alkyl acrylates or methacrylates and the above functional groups. Examples include boronized basic nitrogen compounds selected from the group consisting of products prepared by copolymerization with the monomers of the above, as well as combinations thereof. A preferred boring dispersant is a succinimide derivative having boron, such as, for example, borated polyisobutenyl succinimide.

An example of a borated ashless dispersant is a borated ashless hydrocarbyl succinimide dispersant prepared by reacting hydrocarbyl succinic acid or anhydride with an amine. Preferred hydrocarbyl succinic acid or anhydrides are those in which the hydrocarbyl group is _{derived from a polymer of C 3} or C ₄ monoolefin, especially polyisobutylene, with a polyisobutenyl group of 700-5,000, more preferably 900-2,500. It is like having a number average molecular weight (Mn) of. Such dispersants generally have at least one, preferably 1-2, more preferably 1.1-1.8 succinic acid groups in each polyisobutenyl group. In one embodiment, the oil-soluble or oil-dispersible boried polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of about 550 to about 5000. In one embodiment, the oil-soluble or oil-dispersible boried polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of about 550 to about 4000. In one embodiment, the oil-soluble or oil-dispersible boried polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of about 550 to about 3000. In one embodiment, the oil-soluble or oil-dispersible boried polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of more than about 550 and up to about 2300. In one embodiment, the oil-soluble or oil-dispersible boried polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of about 950 to about 2300. In one embodiment, the oil-soluble or oil-dispersible boried polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of about 950 to about 1300. In one embodiment, the oil-soluble or oil-dispersible boried polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of about 2300. In one embodiment, the oil-soluble or oil-dispersible boried polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of about 1300. In one embodiment, the oil-soluble or oil-dispersible boried polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of about 1000.

Preferred amines for the reaction to form succinimide are polyamines with 2-60 carbon atoms and 2-12 nitrogen atoms per molecule. Particularly preferred is the structure (3):
NH ₂ (CH ₂ ) _n- (NH (CH ₂ ) _n ) _m- NH ₂
Structure (3)
It is a polyalkylene amine represented by, in which n is 2 to 3 and m is 0 to 10. Examples include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, tetrapropylenepentamine, pentaethylenehexamine and the like, and commercially available mixtures of such polyamines. Amines containing other groups, such as hydroxy groups, alkoxy groups, amide groups, nitride groups and imidazoline groups, can also be used, such as polyoxyalkylene polyamines. Alkenyl succinic acid or anhydride to polyamines generally have a molar ratio of about 1: 1 to 10: 1, preferably 1: 1-3: 1, preferably about 1: 1. The amine reacts with alkenyl succinic acid or anhydride by heating at 100 ° C. to 250 ° C., preferably 125 ° C. to 175 ° C. for 1-10 hours, preferably 2-6 hours.

Borylation of alkenyl succinimide dispersants is also well known in the art, as disclosed in US Pat. Nos. 3,087,936 and 3,254,025. Succinimide uses, for example, a boron compound selected from the group consisting of boron, boron oxide, boron halides, boronic acids and esters thereof, and has a boron atom ratio of 0.1 for each atomic ratio of nitrogen in the dispersant. It may be processed in an amount providing from to 10 boron atom ratios.

Borylation products typically contain 0.1 to 2.0% by weight, preferably 0.2 to 0.8% by weight, based on the total weight of the boring dispersant. Boron is believed to exist as a dehydrated borate polymer that binds to the metaborate of the imide. In the boring treatment reaction, 1 to 3% by weight of the above boron compound, preferably boric acid, is added to the dispersant as a slurry in mineral oil based on the weight of the dispersant, and the temperature is 135 ° C. to 165 for 1 to 5 hours. It is easily carried out by heating with stirring at ° C. and then filtering to remove nitrogen from the product. Alternatively, boric acid may be added to the hot reaction mixture of succinic acid or anhydride and amine while removing water.

The boron-containing dispersant is present in an amount sufficient to supply 100-1000 ppm, 100-900 ppm, 100-800 ppm, 100-700 ppm of boron based on the total weight of the lubricating oil composition.

Other Dispersants Dispersants retain in the suspension oil-insoluble substances resulting from oxidation during engine operation, thereby preventing sludge from agglomerating and settling or depositing on metal parts. Dispersants useful herein include nitrogen-containing ashless (metal-free) dispersants known to be effective in reducing the formation of deposits when used in gasoline and diesel engines. Be done.

Suitable dispersants include hydrocarbyl succinimide, hydrocarbyl succinimide, mixed esters / amides of hydrocarbyl-substituted succinic acid, hydroxyesters of hydrocarbyl-substituted succinic acid, and Mannig condensation products of hydrocarbyl-substituted phenols, formaldehyde and polyamines. .. Condensation products of polyamines and hydrocarbyl-substituted phenylic acids are also suitable. Mixtures of these dispersants can also be used.

Basic nitrogen-containing ashless dispersants are well-known lubricating oil additives, and their preparation methods are widely described in the patent literature. Preferred dispersants are alkenyl succinimide and alkenyl succinimide, wherein the alkenyl substituent is preferably a long chain with more than 40 carbon atoms. These materials are readily produced by reacting a hydrocarbyl-substituted dicarboxylic acid material with an amine functional group-containing molecule. Examples of suitable amines are polyamines such as polyalkylene polyamines, hydroxy-substituted polyamines and polyoxyalkylene polyamines.

As is known in the art, the dispersant may be post-treated (eg, with a boring agent or cyclic carbonic acid).

The nitrogen-containing ashless (metal-free) dispersant is basic and contributes to the TBN of the lubricating oil composition to which the dispersant is added without resulting in additional sulfated ash.

The dispersant is 0.1 to 10% by weight (eg, 0.5 to 8% by weight, 0.7 to 7% by weight, 0.7 to 6% by weight, based on the active substance level of the lubricating oil composition. It may be present in 0.7 to 6% by weight, 0.7 to 5% by weight, 0.7 to 4% by weight).

Nitrogen from the dispersant exceeds 0.0050% by weight and up to 0.30% by weight (eg, 0.0050 to 0.10% by weight, 0.%, based on the weight of the dispersant in the finished oil. 0050 to 0.080% by weight, 0.0050 to 0.060% by weight, 0.0050 to 0.050% by weight, 0.0050 to 0.040% by weight, 0.0050 to 0.030% by weight) do.

Cleaners Examples of cleansers that can be used include oil-soluble and perbasic sulfonates, sulfur-free phenates, sulfides of metals, especially alkali metals or alkaline earth metals such as barium, sodium, potassium, lithium, calcium and magnesium. Examples include phenate, salixarate, salicylate, saligenin, composite and naphthenate detergents, and other oil-soluble alkylhydroxybenzoates. The most commonly used metals are calcium and magnesium (both of which may be present in the detergent used in the lubricant) and a mixture of calcium and / or magnesium and sodium.

Perbasic metal detergents include hydrocarbons such as sulfonic acids, acid of cleaning agents such as alkylhydroxybenzoate, metal oxides or hydroxides (eg calcium oxide or calcium hydroxide) and xylene, methanol and water. It is generally made by carbonizing a mixture of accelerators. For example, in order to prepare hyperbasic calcium sulfonate, calcium oxide or calcium hydroxide reacts with gaseous carbon dioxide in the process of carbonation to form calcium carbonate. Sulfonic acids are neutralized by excess CaO or Ca (OH) ₂ to form sulfonates.

The overbasic detergent may be low overbasic, and may be, for example, a superbasic salt having a TBN of less than 100 relative to the active substance. In one aspect, the TBN of the low hyperbasic salt may be from about 30 to about 100. In another aspect, the TBN of the low hyperbasic salt may be from about 30 to about 80. The superbasic detergent may be moderately hyperbasic, and may be, for example, a superbasic salt having a TBN of about 100 to about 250 relative to the active substance. In one aspect, the TBN of the medium hyperbasic salt may be from about 100 to about 200. In another aspect, the TBN of the medium hyperbasic salt may be from about 125 to about 175. The superbasic detergent may be highly hyperbasic, and may be, for example, a superbasic salt having a TBN of more than 250 relative to the active substance. In one aspect, the TBN of the highly hyperbasic salt may be from about 250 to about 800 relative to the active material.

In one aspect, the cleaning agent can be one or more alkali metal salts or alkaline earth metal salts of alkyl-substituted hydroxy aromatic carboxylic acids. Suitable hydroxy aromatic compounds include monocyclic monohydroxyl group and polyhydroxyl aromatic hydrocarbons having 1 to 4, preferably 1 to 3 hydroxy groups. Suitable hydroxy aromatic compounds include phenol, catechol, resorcinol, hydroquinone, pyrogallol, cresol and the like.

Generally, the amount of cleaning agent is about 0.001% to about 50% by weight, or about 0.05% to about 25% by weight, or about 0, based on the total weight of the lubricating oil composition. It can be from 1% to about 20% by weight, or from about 0.01 to 15% by weight.

Anti-Abrasion Agents The lubricating oil compositions disclosed herein can include one or more anti-wear agents. Anti-wear agents reduce the wear of metal parts. Suitable anti-wear agents include dihydrocarbyl dithiophosphate metal salts, such as the following structure 8,
Zn [SP (= S) (OR ¹ ) (OR ² )] _{2 (} 8)
In the zinc dihydrocarbyl dithiophosphate (ZDDP), in the formula, R ¹ and R ² have 1 to 18 (eg, 2 to 12) carbon atoms and, for example, alkyl, alkenyl, aryl, arylalkyl, Included is zinc dihydrocarbyl dithiophosphate (ZDDP), which may be the same or different hydrocarbyl groups, including groups such as aryl and alicyclic groups. Particularly preferred as the R ¹ and R ² groups are alkyl groups having 2 to 8 carbon atoms (eg, alkyl groups are ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, It may be n-pentyl, isopentyl, n-hexyl, isohexyl, 2-ethylhexyl). To obtain oil solubility, the total number of carbon atoms (ie, R ¹ + R ² ) is at least five. Therefore, zinc dihydrocarbyl dithiophosphate can include zinc dialkyl dithiophosphate. Zinc dialkyldithiophosphate is a primary zinc dialkyldithiophosphate, a secondary zinc dialkyldithiophosphate, or a combination thereof. ZDDP may be present in 3% by weight or less (eg, 0.1 to 1.5% by weight or 0.5 to 1.0% by weight) of the lubricating oil composition. In one embodiment, the lubricating oil composition containing the magnesium salicylate detergent described herein further comprises an antioxidant compound. In one embodiment, the antioxidant is a diphenylamine antioxidant. In another embodiment, the antioxidant is a hindered phenolic antioxidant. In yet another aspect, the antioxidant is a combination of a diphenylamine antioxidant and a hindered phenolic antioxidant.

Antioxidants The lubricating oil compositions disclosed herein can contain one or more antioxidants. Antioxidants reduce the tendency of mineral oils to deteriorate during use. Oxidative degradation can be evidenced by sludge in the lubricant, varnish-like deposits on the metal surface and increased viscosity. Suitable antioxidants include hindered phenols, aromatic amines, and alkyl sulfides and alkali metal and alkaline earth metal salts thereof.

Hindered phenolic antioxidants often contain a secondary butyl group and / or a tertiary butyl group as steric hindrance groups. The phenol group may be further substituted with a hydrocarbyl group (usually a straight chain or branched chain alkyl) and / or a bridging group attached to a second aromatic group. Examples of suitable hindered phenol antioxidants are 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol, 4-ethyl-2,6-di-tert-butylphenol. , 4-propyl-2,6-di-tert-butylphenol, 4-butyl-2,6-di-tert-butylphenol and 4-dodecyl-2,6-di-tert-butylphenol. Other useful hindered phenolic antioxidants include 2,6-di-alkyl-phenol propionic acid ester derivatives such as IRGANOX® L-135 from Ciba, and bisphenol. Antioxidants include, for example, 4,4'-bis (2,6-di-tert-butylphenol) and 4,4'-methylenebis (2,6-di-tert-butylphenol).

A typical aromatic amine antioxidant has at least two aromatic groups attached directly to one amine nitrogen. A typical aromatic amine antioxidant has an alkyl substituent having at least 6 carbon atoms. Specific examples of the aromatic amine antioxidants useful herein include 4,4'-dioctyldiphenylamine, 4,4'-dinonyldiphenylamine, N-phenyl-1-naphthylamine, N- (4-tert-). Examples thereof include octylphenyl) -1-naphthylamine and N- (4-octylphenyl) -1-naphthylamine. The antioxidant may be present in 0.01-5% by weight (eg 0.1-2% by weight) of the lubricating oil composition.

Antifoaming Agent The lubricating oil composition disclosed herein can include one or more antifoaming agents that destroy bubbles in the oil. Non-limiting examples of suitable defoaming agents or antifoaming inhibitors include silicone oils or polydimethylsiloxanes, fluorosilicones, alkoxylated fatty acids, polyethers (eg polyethylene glycol), branched polyvinyl ethers, alkyl acrylate polymers, alkyl methacrylates. Examples include polymers, polyalkoxyamines, and combinations thereof.

Additional Co-Additives The lubricating oil compositions of the present disclosure may also contain other conventional additives. These additives can be dispersed or dissolved in the lubricating oil composition to impart any desired properties to the lubricating oil composition, or to improve the properties. Any additive known to those of skill in the art may be used in the lubricating oil compositions disclosed herein. Some suitable additives are Mortier et al., "Chemistry and Technology of Lubricants", 2nd Edition, London, Springer (1996) and Leslie R. et al. Leslie R. Rudnik, Lubricant Additives: Chemistry and Applications, NY, Marcel Dekker (2003), both incorporated herein by reference. Is done. For example, lubricating oil compositions include antioxidants, anti-wear agents, cleaning agents such as metal cleaning agents, rust inhibitors, dehaze agents, anti-emulsifiers, metal deactivators, friction modifiers, flow point depressants, erasing agents. It can be blended with foaming agents, co-solvents, corrosion inhibitors, ashless dispersants, multifunctional agents, dyes, extreme pressure additives, etc. and mixtures thereof. Various additives are known and commercially available. These additives or similar compounds thereof can be used in the preparation of the lubricating oil compositions of the present disclosure in the usual formulation procedure.

In the preparation of lubricating oil formulations, it is common to introduce additives into hydrocarbon oils, such as mineral lubricating oils or other suitable solvents, in the form of 10-100% by weight active ingredient concentrates.

Generally, these concentrates are diluted with 3 to 100 parts by weight, for example 5 to 40 parts by weight, of lubricant per part by weight of the additive package in forming the finished lubricant, such as crankcase motor oil. May be done. The purpose of the concentrate is, of course, to make the handling of various materials easier and easier to handle, and to facilitate dissolution or dispersion in the final formulation.

Each of the above-mentioned additives is used in an amount that is functionally effective in imparting the desired properties to the lubricant at the time of use. Thus, for example, when the additive is a friction modifier, the functionally effective amount of the friction modifier is sufficient to impart the desired friction modifier to the lubricant.

In general, the concentration of each additive in the lubricating oil composition, when used, is about 0.001% by weight to about 20% by weight, about 0.01% by weight, based on the total weight of the lubricating oil composition. Can be in the range of ~ about 15% by weight, or about 0.1% by weight to about 10% by weight, about 0.005% by weight to about 5% by weight, or about 0.1% by weight to about 2.5% by weight. .. Further, the total amount of the additives in the lubricating oil composition is about 0.001% by weight to about 20% by weight, about 0.01% by weight to about 10% by weight, or about 10% by weight, based on the total weight of the lubricating oil composition. It can range from about 0.1% by weight to about 5% by weight.

Additional base oils with lubricating viscosity Oils with lubricating viscosity (sometimes referred to as "basestock" or "base oil") are the major liquid constituents of lubricants, in which additives, And optionally other oils are blended to produce, for example, the final lubricant (ie, lubricant composition). The base oil is useful in producing concentrates and from it in producing lubricating oil compositions and can be selected from natural and synthetic lubricating oils and combinations thereof.

Natural oils include animal and vegetable oils, liquid petroleum, and hydrorefined, solvent-treated mineral lubricants of paraffinic, naphthenic and mixed paraffinic and naphthenic. Oils with a lubricating viscosity, derived from coal or shale, are also useful base oils.

Synthetic lubricants include hydrocarbon oils such as polymerized and copolymerized olefins (eg polybutylene, polypropylene, propylene-isobutylene copolymers, chlorinated polybutylene, poly (1-hexene), poly (1-octene), poly (1). -Decenes))), alkylbenzenes (eg dodecylbenzene, tetradecylbenzene, dinonylbenzene, di (2-ethylhexyl) benzene), polyphenols (eg biphenyl, terphenyl, alkylated polyphenols), and alkylated diphenyl ethers and alkylated Includes diphenylsulfides and their derivatives, analogs and homologues.

The base oil may be derived from Fischer-Tropsch synthetic hydrocarbons. Fischer-Tropsch synthetic hydrocarbons are produced from synthetic gases containing _{H 2 and CO using Fischer-Tropsch catalysts.} Such hydrocarbons usually require further processing to be useful as a base oil. Hydrocarbons may be hydrogen isomerized, hydrocracked and hydrogen isomerized, dewaxed, or hydrogen isomerized and desorbed using methods known to those of skill in the art, for example.

The base oil may be derived from Fischer-Tropsch synthetic hydrocarbons. Fischer-Tropsch synthetic hydrocarbons are produced from synthetic gases containing _{H 2 and CO using Fischer-Tropsch catalysts.} Such hydrocarbons usually require further processing to be useful as a base oil. Hydrocarbons may be hydrogen isomerized, hydrocracked and hydrogen isomerized, dewaxed, or hydrogen isomerized and desorbed using methods known to those of skill in the art, for example.

Unrefined oils, refined oils and re-refined oils can be used in the lubricating oil compositions of the present invention. Unrefined oils are like those obtained directly from natural or synthetic sources without any additional refining process. For example, shale oils obtained directly from the carbonization operation, petroleums obtained directly from distillation, or ester oils obtained directly from the esterification process, these oils used without subsequent treatment. Is unrefined oil. Refined oils are oils similar to unrefined oils, except that they are further processed in one or more refining steps to improve one or more properties. Many such purification techniques, such as distillation, solvent extraction, acid or base extraction, filtration and permeation, are known to those of skill in the art.

The rerefined oil is applied to the refined oil that has already been used and is obtained by a method similar to the method used to obtain the refined oil. Such rerefined oils are also known as regenerated or reprocessed oils and are often further processed by techniques for obtaining approval for used additives and oil decomposition products.

Therefore, the base oils that can be used to make the lubricating oil compositions of the present invention are set forth in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines (API Publication 1509). It may be selected from any of the base oils of groups IV. The groups of such base oils are summarized in Table 1 below.

Oils having a lubricating viscosity (also referred to as base oils) for use in the lubricating oil compositions of the present disclosure are usually in major amounts, preferably greater than 50% by weight, based on the total weight of the composition. It is present in an amount greater than about 70% by weight, more preferably in an amount of about 80 to about 99.5% by weight, most preferably in an amount of about 85 to about 98% by weight. As used herein, the term "base oil" is produced by a single manufacturer for the same specifications (regardless of source material or manufacturer's location), meets the specifications of the same manufacturer, and meets the same manufacturer's specifications. It is understood to mean a basestock or basestock formulation that is a lubricant component, identified by a unique formulation, product identification number, or both. The base oils used herein are used in the preparation of lubricating oil compositions for all applications such as engine oils, marine cylinder oils, functional fluids (hydraulic oils, gear oils, transmission fluids, etc.). It can be an oil of any lubricating viscosity that is currently known or will be discovered in the future. In addition, the base oils used herein can optionally contain viscosity index improvers such as polymeric alkyl methacrylates, olefin copolymers (eg ethylene-propylene copolymers or styrene-butadiene copolymers) and combinations thereof.

Characteristics of Finished Lubricants Generally, the kinematic viscosity of the lubricating oil composition at 100 ° C. (according to ASTM D445) is up to 9.3 mm ² / s, preferably 3.8-9.3 mm ² / s, 3 .8~8.2mm is a ^{2 /s,3.8~7.1mm 2 /s,3.8~6.1mm 2} / s.

Generally, the high temperature and high shear (“HTHS”) viscosity (according to ASTM D4683) at 150 ° C. of the lubricating oil composition is 1.3 to 2.6 mPa · s, 1.3 to 2.4 mPa · s, 1. The range is 3 to 2.2 mPa · s, 1.3 to 2.0 mPa · s, and 1.3 to 1.8 mPa · s.

Generally, the high temperature high shear (“HTHS”) viscosity of the lubricating oil composition at 80 ° C. is less than 4.5 mPa · s.

Generally, the NOACK volatility of the lubricating oil composition (according to ASTM D5800B) is 22.0% by weight or less, 21.0% by weight or less, 20.0% by weight or less, 19.0% by weight or less, 18.0. Weight% or less, 17.0% by weight or less, 16.0% by weight or less, 15.0% by weight or less, 14.5% by weight or less, 14.0% by weight or less, 13.5% by weight or less, 13.0% by weight % Or less, 12.5% by weight or less, 12.0% by weight or less, 11.5% by weight or less, 11.0% by weight or less, 10.5% by weight or less, 10.0% by weight or less. Normally, NOACK volatility is at least 4.0% by weight. In other embodiments, NOACK volatility is 15.0 to 2.0% by weight, 15.0 to 3.0% by weight, 14.5 to 5.0% by weight, 14.5 to 7.0% by weight, It is 14.5 to 8.0% by weight and 14.5 to 9.0% by weight.

The following examples are presented to illustrate examples of embodiments of the present disclosure, but are not intended to limit this disclosure to the particular embodiments described. Unless otherwise stated, all parts and percentages are weight-based. All numbers are approximate. If a range of numbers is indicated, it should be understood that embodiments outside the stated range may still be within the scope of the present disclosure. The particular details given in each example should not be construed as a necessary feature of the present disclosure.

It will be appreciated that various changes may be made to the embodiments disclosed herein. Therefore, the above description should not be construed as a limitation, but as a mere example of a preferred embodiment. For example, the functions described above and performed as the best mode for operating the present disclosure are for illustration purposes only. Other adjustments and methods may be implemented by those skilled in the art to the extent that they do not deviate from the scope and intent of this disclosure. In addition, one of ordinary skill in the art will assume other changes within the scope and intent of the claims attached herein.

(Example)
The following examples are for illustration purposes only and do not limit the scope of this disclosure in any way.

Comparative Example 1
A lubricating oil composition was prepared by adding 100% by weight bis-2-ethylhexyl azelate base oil. The formulation had 21.7% NOACK volatility and 3.61 mPa · s HTHS80.
Comparative Example 2
97 wt% UNISTER® (registered trademark in any country) M-480R (NOF CORPORATION, 2 cSt), and 3 wt% boronized polyisobutenylbis-succinimide dispersant based on the concentrate. A lubricating oil composition was prepared by adding a dispersant having a number average molecular weight of polyisobutene of about 1300 and providing about 0.019 wt% boron to the finished oil. The formulation had 34.3% NOACK volatility and 2.60 mPa · s HTHS80.

Comparative Example 3
99% by weight bis-2-ethylhexyl azelate base oil and 0.79% by weight based on concentrate, a boronized polyisobutenyl bis-succinimide dispersant with a polyisobutene number average molecular weight of about 1300. A lubricating oil composition was prepared by adding a dispersant providing about 0.005% by weight of boron to the finished oil. The formulation had 21.4% NOACK volatility and 3.87 mPa · s HTHS80.

Comparative Example 4
97% by weight of Group II base oil (KV100 = 3.05, VI = 106) and 3% by weight of boronized polyisobutenylbis-succinimide dispersant based on the concentrate, with a number average of polyisobutene. A lubricating oil composition was prepared by adding a dispersant having a molecular weight of about 1300 and providing about 0.019 wt% boron to the finished oil. The formulation had 36.0% NOACK volatility and 3.94 mPa · s HTHS80.

Comparative Example 5
97% by weight of Group III base oil (KV100 = 4.19, VI = 125) and 3% by weight of boronized polyisobutenylbis-succinimide dispersant based on the concentrate, with a number average of polyisobutene. A lubricating oil composition was prepared by adding a dispersant having a molecular weight of about 1300 and providing about 0.019 wt% boron to the finished oil. The formulation had 13.0% NOACK volatility and 5.62 mPa · s HTHS80.

Comparative Example 6
97 wt% di-isotridecyl adipate base oil (5 cSt) and 3 wt% boborated polyisobutenylbis-succinimide dispersant based on the concentrate, with a polyisobutene number average molecular weight of about 1300. A lubricating oil composition was prepared by adding a dispersant providing about 0.019% by weight of boron to the finished oil. The formulation had 3.10% NOACK volatility and 7.26 mPa · s HTHS80.

Comparative Example 7
99% by weight bis-2-ethylhexyl azelate base oil, and 0.37% by weight HOB boronized sulfonate cleaning agent relative to the concentrate, providing approximately 0.015% by weight of boron to the finished oil. A lubricating oil composition was prepared by adding a cleaning agent. The formulation had 21.0% NOACK volatility and 3.71 mPa · s HTHS80.

Comparative Example 8
A 99% by weight bis-2-ethylhexyl azelate base oil and a 0.22% by weight potassium borate dispersion relative to the concentrate to provide about 0.015% by weight boron in the finished oil. A lubricating oil composition was prepared by adding the dispersion. The formulation had 20.8% NOACK volatility and 3.58 mPa · s HTHS80.

Comparative Example 9
99% by weight bis-2-ethylhexyl azelate base oil and 0.62% by weight glycerol monooleate friction modifier relative to the concentrate, approximately 0.015% by weight in the finished oil. Lubricating oil compositions were prepared by adding a friction modifier that provides boron. The formulation had 20.6% NOACK volatility and 3.59 mPa · s HTHS80.

Example 1
98% by weight of bis-2-ethylhexyl azelate base oil and 1.59% by weight of the concentrated polyisobutenyl bis-succinimide dispersant with a number average molecular weight of polyisobutene of about 1300. A lubricating oil composition was prepared by adding a dispersant providing about 0.008% by weight of boron to the finished oil. The formulation had 17.7% NOACK volatility and 3.73 mPa · s HTHS80.

Example 2
A 97% by weight bis-2-ethylhexyl azelate base oil and a 3% by weight boborated polyisobutenyl bis-succinimide dispersant based on the concentrate, the polyisobutene having a number average molecular weight of about 1300. A lubricating oil composition was prepared by adding a dispersant providing about 0.019 wt% boron to the finished oil. The formulation had 16.4% NOACK volatility and 4.01 mPa · s HTHS80.

Example 3
48% by weight bis-2-ethylhexyl azelate base oil, 48% by weight Group III base oil (KV100 = 4.19, VI = 125) and 3% by weight based on concentrate polyisobutenylbis. A lubricating oil composition was prepared by adding a dispersant which is a succinimide dispersant and has a number average molecular weight of polyisobutene of about 1300 and provides about 0.019% by weight of boron to the finished oil. The formulation had 15.9% NOACK volatility and 4.50 mPa · s HTHS80.

Example 4
98% by weight of bis-2-ethylhexyl azelate base oil and 2.38% by weight of the boronized polyisobutenyl bis-succinimide dispersant based on the concentrate, with a polyisobutene number average molecular weight of about 1300. A lubricating oil composition was prepared by adding a dispersant providing about 0.015% by weight of boron to the finished oil. The formulation had 16.7% NOACK volatility and 4.05 mPa · s HTHS80.

Example 5
96% by weight of bis-2-ethylhexyl azelate base oil and 3.97% by weight of the boronized polyisobutenyl bis-succinimide dispersant based on the concentrate, with a polyisobutene number average molecular weight of about 1300. A lubricating oil composition was prepared by adding a dispersant providing about 0.025% by weight of boron to the finished oil. The formulation had 15.9% NOACK volatility and 4.30 mPa · s HTHS80.

Example 6
96% by weight of bis-2-ethylhexyl azelate base oil and 3% by weight of the boronized polyisobutenyl bis-succinimide dispersant based on the concentrate, the number average molecular weight of polyisobutene is about 1000. A lubricating oil composition was prepared by adding a dispersant providing about 0.018% by weight of boron to the finished oil. The formulation had 15.0% NOACK volatility and 3.85 mPa · s HTHS80.

Table 1 shows the measured viscosity characteristics and NOACK volatility performance of the lubricating oil. The examples of the present invention show a synergistic effect of a combination of a borated dispersant and a low viscosity diester base oil (bis-2-ethylhexyl azelate), which results in low NOACK volatility while maintaining low HTHS80. ing. In Example 3 of the present invention, it is shown that a mixture of a diester base oil and a conventional base oil also works well.

On the other hand, in Comparative Example 2 and Comparative Example 4, it is shown that the monoester base oil or the conventional base oil alone does not function in almost the same manner in the NOACK test. Higher viscosity base oils, such as those used in Comparative Examples 5 and 6, produce low NOACK volatility, while the resulting HTHS80 is high for fuel economy benefits. Not desirable. Comparative Examples 7-9 also show that boron sources other than the boring dispersant are not effective in reducing NOACK volatility.

Claims (15)

Lubricating oil composition
a. Less than,

A base oil containing a diester having one of the structures of, each R being an independently _{saturated or unsaturated alkyl group of C 1 to} C ₂₀ , where n is an integer of 1 to 8, said. The base oil, wherein the diester has an ASTM D445 kinematic viscosity at 100 ° C. of 2.5 to 3.5 mm ² / s and an ASTM D2270 kinematic viscosity index of 110 to 175.
b. The lubricating oil composition containing 75 to 500 ppm of boron based on the total weight of the lubricating oil composition, and the boron provided from one or more kinds of boron-containing dispersants. The lubricating oil composition according to claim 1, wherein the lubricating oil composition has a high shear viscosity at 80 ° C. of less than 4.5 mPa · s. Cleaners, anti-wear agents, antioxidants, defoamers, rust inhibitors, dehaze agents, anti-emulsifiers, metal deactivators, friction modifiers, flow point depressants, co-solvents, corrosion inhibitors, ashless dispersants , Further containing multifunctional agents, dyes or extreme pressure additives,
The lubricating oil composition according to claim 1. The lubricating oil composition according to claim 1, wherein the boron-containing dispersant is borated polyisobutenyl succinimide or borated polyalkenyl succinic anhydride. The lubricating oil composition according to claim 1, further comprising an additional base oil. A method of reducing evaporation loss in an internal combustion engine.
a. Less than,

A base oil containing a diester having one of the structures of, each R is independently selected from the group consisting of saturated or unsaturated alkyl groups of _{C 1 to} C _{20, where n is an integer of 1 to 8.} The base oil has a kinematic viscosity of 2.5 to 3.5 mm ² / s at 100 ° C. according to ASTM D445 and a viscosity index of 110 to 175 according to ASTM D2270. When,
b. The engine is lubricated with a lubricating oil composition containing 75 to 500 ppm of boron based on the total weight of the lubricating oil composition and the boron provided from one or more boron-containing dispersants. How to include that. The method according to claim 6, wherein the lubricating oil composition has a high shear viscosity at 80 ° C. of less than 4.5 mPa · s. The lubricating oil composition is a cleaning agent, an anti-wear agent, an antioxidant, an antifoaming agent, a rust preventive, a dehaze agent, an anti-emulsifying agent, a metal deactivator, a friction modifier, a flow point lowering agent, a co-solvent, and the like. The method of claim 6, further comprising a corrosion inhibitor, an ashless dispersant, a multifunctional agent, a dye or an extreme pressure additive. The method according to claim 6, wherein the boron-containing dispersant is borated polyisobutenyl succinimide or borated polyalkenyl succinic anhydride. The method of claim 6, wherein the lubricating oil composition further comprises an additional base oil. It ’s a way to improve the fuel efficiency of the engine.
a. Less than,

A base oil containing a diester having one of the structures of, each R is independently selected from the group consisting of saturated or unsaturated alkyl groups of _{C 1 to} C _{20, where n is an integer of 1 to 8.} The diester has a kinematic viscosity of 2.5 to 3.5 mm ² / s at 100 ° C. according to ASTM D445 and a viscosity index of 110 to 175 according to ASTM D2270. When,
b. The engine is lubricated with a lubricating oil composition containing 75 to 500 ppm of boron based on the total weight of the lubricating oil composition and the boron provided from one or more boron-containing dispersants. How to include that. The method according to claim 11, wherein the lubricating oil composition has a high shear viscosity at 80 ° C. of less than 4.5 mPa · s. The lubricating oil composition is a cleaning agent, an anti-wear agent, an antioxidant, an antifoaming agent, a rust preventive, a dehaze agent, an anti-emulsifying agent, a metal deactivator, a friction modifier, a flow point lowering agent, a co-solvent, and the like. The method of claim 11, further comprising a corrosion inhibitor, an ashless dispersant, a multifunctional agent, a dye or an extreme pressure additive. 11. The method of claim 11, wherein the boron-containing dispersant is borated polyisobutenyl succinimide or borated polyalkenyl succinic anhydride. The method of claim 11, wherein the lubricating oil composition further comprises an additional base oil.