KR20070084350A - Dispersant - Google Patents

Abstract

A novel ashless polymeric dispersant is claimed which is suitable for use in an automotive lubricant composition. The ashless polymeric dispersant has a number average molecular weight of between 200 and 15, 000 and derived from the reaction of a polar head group, which comprises a polar moiety having more than one amine, alcohol, acid or halogen functionality with two or more polar tail groups where each polar tail group comprises a polymeric backbone of 2 to 30 monomeric repeat units, each repeat unit comprising a hydrocarbon chain functionalised by the presence of at least one electronegative element or moiety. The dispersant has good dispersancy properties, when used as a sole dispersant or in combination with other dispersants. It provides enhanced seal resistance and has good oxidative stability in automotive applications as compared to current commercial products. Furthermore the low temperature viscosity of an automotive lubricant composition containing the dispersant is superior to that of a composition with current commercial dispersants.

Description

Dispersant {DISPERSANT}

The present invention relates to novel ashless polymeric dispersants and their use in automotive lubricant compositions.

In automotive applications, the functions performed by lubricant base fluids and various additives are all important. Suspension and surface cleanliness of insoluble contaminants is an important additional function, which is ensured by the combination of detergents and dispersants. Dispersants are usually more effective in fulfilling the flotation and cleaning requirements because they have a higher molecular weight than the “soap portion” of the cleaner.

In automotive engine oils, dispersants may be used to float insoluble contaminants in lubricant base oils in various ways to reduce the increase in viscosity of the engine oil due to soot, reduce engine sludge, and reduce deposits formed on the engine. Can be. Dispersants in transmission fluids are a major additive for controlling the increase in sludge derived from oxidation of strong lubricant base oils as certain parts of the transmission become very hot. Dispersants may also be used in gear oils. Gear oils typically contain thermally labile extreme pressure additives that can decompose and form high polar byproducts. Dispersants are used to receive these byproducts and to avoid corrosion and deposit formation.

As mentioned above, the main function of the dispersant in automotive lubricant compositions is to disperse soot, deposit precursors and deposits. However, dispersants require different properties for effective performance. Such properties include thermal and oxidative stability, good low temperature properties (i.e., maintenance of low viscosity), and maintenance of the integrity of the sealant in automotive equipment.

Dispersants with poor thermal stability will decompose and lose their ability to associate and float with harmful products. Dispersants with poor oxidative stability will by themselves cause deposit formation and oil thickening.

Combining the amount of dispersant present in an automotive lubricant composition (eg up to 20% in automotive engine oil) with the fact that the dispersant is often an additive of the highest molecular weight, with the exception of viscosity index improvers, can change the viscosity of the lubricant composition. . At higher temperatures, an increase in viscosity is preferred, but at lower temperatures, an increase in viscosity is disadvantageous. Automotive engine oils are required to be low to medium in viscosity for cranking viscosity and pumping viscosity during operation in cold weather. For ease of low temperature cranking, good lubricant circulation and fuel costs, it is important for automotive lubricant compositions to have good low temperature properties. In the automotive sector, fuel cost is an important factor.

Sealants in automotive devices are used for a variety of purposes, in particular to provide access to broken parts for repair, to minimize lubricant contamination and loss, to vibrate parts or parts that can expand or contract when exposed to different temperatures. Used to combine them. Thus, maintaining the integrity of the sealant, which can be inhibited by shrinkage, elongation or embrittlement, is important for the operational performance of automotive equipment. Although the addition of a seal swelling agent can mitigate sealant damage to some extent, dispersants are often involved as additives that cause damage to the sealant.

Commercially available dispersants typically consist of a nonpolar hydrocarbon chain tail group, a linker connected thereto and a polar head group connected thereto. Typically, polar groups associate polar particles and nonpolar groups allow these particles to be suspended in the bulk lubricant. The most common of this type of dispersant is polyisobutylene succinimide which is derived by reacting polyisobutylene with maleic anhydride followed by polyalkylenepolyamine. Such products have good dispersibility but are known to cause sealant damage.

The present inventors have improved dispersibility when used alone or in combination with other dispersant (s), and also provide lubricant base oils in automotive articles that provide enhanced sealant resistance as compared to current commercially available products. Dispersants were designed for use together. In addition, the low temperature viscosity of automotive lubricant compositions with this dispersant is superior to the low temperature viscosity of compositions with dispersants currently commercially available.

According to the present invention, a number average molecular weight is 200-15,000 and is derived from the reaction of two or more polar tail groups with a polar head group comprising a polar moiety having more than one amine, alcohol, acid or halogen function, each of which The polar tail groups of disclose an ashless polymer dispersant suitable for use in automotive lubricant compositions comprising from 2 to 30 polymer backbones of monomer repeat units each comprising a hydrocarbon chain functionalized by one or more electronegative elements or moieties.

According to a further embodiment of the invention, from the reaction of a polar head group with two or more polar tail groups having a number average molecular weight of 200 to 15,000 and comprising a polar moiety having more than one amine, alcohol, acid or halogen functional group And wherein each polar tail group is used in an automotive lubricant composition of an ashless polymer dispersant comprising 2 to 30 polymer backbones of monomer repeat units each comprising a hydrocarbon chain functionalized by one or more electronegative elements or moieties. To start.

According to a further embodiment of the present invention, there is provided a base oil and a ashless polymer dispersant having a number average molecular weight of 200 to 15,000, wherein the dispersant comprises a polar moiety having more than one amine, alcohol, acid or halogen functional group. Derived from reaction of a polar head group with at least two polar tail groups, each polar tail group comprising from 2 to 30 polymer backbones each comprising a monomer chain functionalized by at least one electronegative element or moiety An automotive lubricant composition is disclosed.

Ashless  polymer Dispersant

Polar head groups include polar moieties having more than one amine, alcohol, acid or halogen function. Preferably, the polar moiety has more than one amine or alcohol moiety. Preferably, the polar moiety has 2 to 4 amine moieties. Examples of polar head groups include polyamines such as tetraethylene pentamine, ethylene diamine, N, N-dimethylaminopropylamine, diethylenetriamine and triethylenetetramine and polyols such as glycerol, sorbitol, trimethylolpropane And neopentyl glycol and pentaerythritol. The polar head group is selected to be capable of associating with the particles and dispersing in the automotive lubricant composition when reacting with two or more tail groups. The polar moiety is selected such that the polarity when reacted with two or more tail groups does not render the ashless polymer dispersant insoluble in the additive and the selected base oil.

The degree of polarity of each of the polar tail groups is such that they exhibit solubility in the combination of selected base oils with other polar additives that may be present in the automotive lubricant composition. Each tail group may be the same or different. Preferably, each tail group is the same.

이고, 전기음성 원소 또는 잔기가 에스테르인 경우이다. The monomer repeat units of the polymer backbone of each polar tail group each comprise a hydrocarbon chain functionalized by one or more electronegative elements or moieties. The hydrocarbon chain may be saturated or unsaturated, preferably saturated aliphatic chain. The hydrocarbon chain can be straight or branched. Preferably branched. Preferably it is a divalent radical. Preferably it contains 8 to 35, more preferably 10 to 25, in particular 12 to 20 carbon atoms. Preferably, the electronegative element or moiety is selected from oxygen, esters (defined as -COO-) and amides (defined as -CONH-). More preferably, the electronegative element or moiety is selected from oxygen or esters, in particular esters. The electronegative element or moiety is preferably in the backbone of the monomer repeat unit rather than as a pendant group. Particularly preferred monomer repeat units are hydrocarbon chains.

When the electronegative element or moiety is an ester.

The number of monomer repeat units is in the range of 2 to 30, preferably 2 to 20, more preferably 3 to 15.

In the dispersant, there are two or more polar tail groups each connected to the polar head group, and preferably two to four. Preferably, one end of each tail group has a functional group that reacts with the polar moiety of the polar head group, for example an acid, anhydride, halogen or alcohol group.

The other end of the tail group terminates with a chain terminator. The exact structure of the chain terminator is not critical as long as it is inert to the other components of the composition under given conventional processing conditions. Preferably, the molecular weight is less than 800, more preferably less than 500, in particular less than 300. Preferably it contains only carbon, hydrogen and oxygen atoms.

The ashless polymer dispersant may be an ABA block copolymer in which A is a tail group and B is a polar head group. Alternatively, the dispersant may be a star polymer or a comb graft polymer.

Preferred dispersants are polyamine polar heads having at least two tail groups which are products obtained by polyesterizing hydroxyalkyl acids with alkyl groups having from 8 to 35 carbon atoms, preferably from 10 to 25, in particular from 12 to 20 carbon atoms. It is induced by reaction with a group.

For each of these tail groups, particularly preferred hydroxyalkyl acids are 12-hydroxystearic acid. In this case, the chain terminator may be derived from hydroxyalkyl acid itself, or from non-hydroxyl analogs of hydroxy acid generally present in commercial grade hydroxy acids. The chain terminator may be derived from any conventional acid that may be added to the polyester reaction mixture. Such conventional acids include saturated or unsaturated, preferably saturated monocarboxylic acids having 12 to 22 carbon atoms. An embodiment is isostearic acid. The terminal of each tail group that reacts with the polar head group is a carboxylic acid group.

Examples of polyamine polar head groups for this preferred dispersant include tetraethylene pentamine, ethylene diamine, N, N-dimethylaminopropylamine, diethylenetriamine and triethylenetetramine. Tetraethylene pentamine is particularly preferred.

The number average molecular weight of the dispersant is 200 to 15,000, preferably 500 to 10,000, more preferably 500 to 7,000. The number average molecular weight of the polymer can be measured by a number of techniques. Gel permeation chromatography (GPC) is a well known technique that has been used to determine the number average molecular weight of the dispersant of the invention.

Base oil

The term base oil includes engine oil, transmission oil and fuel. The term engine oil includes both gasoline and four-stroke diesel (including large diesel) engine oils. The engine oil may be selected from any of Group I to VI base oils or mixtures thereof, as defined by the American Petroleum Institute (API). Preferably, the engine oil has a Group I base oil of 20% or less, more preferably 10% or less. Preferably, the engine oil has a group V base oil of 50% or less. The viscosity at 100 DEG C of the four-stroke engine oil is 3 to 15 cSt, preferably 4 to 8 cSt. The viscosity index is preferably 90 or more, more preferably 105 or more. The noack volatility measured according to ASTM D-5800 is preferably less than 20%, more preferably less than 15%.

The term engine oil also includes two-stroke engine oil. Particularly preferred two-stroke engine oils are Group I base oils, in particular polyisobutylene. Other preferred two-stroke engine oils include some Group V base oils, such as esters and vegetable oils.

Transmission oils include automatic, manual, rear axle and continuous continuously variable transmission oils. Preferred transmission oils are preferably groups II to VI, in particular high viscosity polyalphaolefins and fixative mineral oils.

Fuels include both gasoline and diesel fuels. Preferably, gasoline fuels must conform to the EN 228 standard and diesel fuels must conform to the EN 590 standard.

The base oil is preferably engine oil, more preferably four stroke engine oil.

When the base oil is engine oil, the weight percent of ashless polymer dispersant in the vehicle lubricant composition is preferably 1 to 20%. If the base oil is a transmission oil, the weight percent of ashless polymer dispersant in the automotive lubricant composition is preferably 0.1 to 5%. When the base oil is a fuel, the weight percent of ashless polymer dispersant in the automotive lubricant composition is preferably 0.001 to 1%.

When the base oil is a four-stroke engine oil, the automotive lubricant composition may contain other types of additives of known functionality in amounts of 0.1 to 30%, more preferably 1 to 20%, more particularly 2 to 15% of the total amount of the automotive lubricant composition. It includes more. These additives include antioxidants, corrosion inhibitors, rust inhibitors, friction modifiers, foaming depressants, pour point depressants, viscosity index improvers, antiwear agents, extreme pressure agents, ash-containing detergents, metal deactivators, demulsifiers and mixtures thereof. Can be mentioned. Viscosity index improvers include polyisobutenes, polymethacrylate acid esters, polyacrylate acid esters, diene polymers, polyalkyl styrenes, alkenyl aryl conjugated diene copolymers and polyolefins. Examples of foam reducing agents include silicones and organic polymers. Pour point depressants include polymethacrylates, polyacrylates, polyacrylamides, condensation products of haloparaffin waxes and aromatic compounds, vinyl carboxylate polymers, dialkylfumarates, vinyl esters of fatty acids and alkyl vinyl ethers; Coalescence is mentioned. Friction modifiers include partial fatty acid esters of amides, amines, molybdenum containing compounds, and polyhydric alcohols. Ash-containing detergents include neutral and overbased alkaline earth metal salts of acidic organic compounds. Antioxidants include hindered phenols, sulfur containing compounds and alkyl diphenylamines. Antiwear agents include zinc dialkyldithiophosphate (ZDDP), ash and ash containing organophosphorus and organosulfur compounds, boron compounds and organic molybdenum compounds. Examples of metal deactivators include benzotriazole, mercaptobenzimidazole, thiadiazole and tolutriazole derivatives. Extreme pressure agents include sulfided esters, sulfided olefins, diaryl disulfides, dialkyldithiophosphate esters, heavy metal naphthenates, ash and ash containing dialkyldithiophosphates, ash and ash containing dialkyldithiocarbamates Ashless and ash containing salts of phosphate esters, chlorinated waxes, complex esters, borate esters, and oil insoluble sheet structural compounds such as graphite and molybdenum disulfide suspensions. The demulsifiers include polyalkoxylated phenols, polyalkoxylated polyols, and polyalkoxylated polyamines.

The additive may have more than one functional group in a single additive.

When the base oil is a two-stroke engine oil, the automotive lubricant composition may contain other types of additives of known functionality in amounts of 0.1 to 30%, more preferably 0.5 to 20%, more particularly 1 to 10% of the total amount of the automotive lubricant composition. It includes more. These additives include antioxidants, corrosion inhibitors, rust inhibitors, friction modifiers, foaming agents, pour point depressants, viscosity index improvers, lubricants, ash-containing cleaners and mixtures thereof. Viscosity index improvers include polyisobutenes, polymethacrylate acid esters, polyacrylate acid esters, diene polymers, polyalkyl styrenes, alkenyl aryl conjugated diene copolymers and polyolefins. Examples of foam reducing agents include silicones and organic polymers. Pour point depressants include polymethacrylates, polyacrylates, polyacrylamides, condensation products of haloparaffin waxes and aromatic compounds, vinyl carboxylate polymers, dialkylfumarates, vinyl esters of fatty acids and alkyl vinyl ethers; Coalescence is mentioned. Friction modifiers include partial fatty acid esters of amides, amines, molybdenum containing compounds, and polyhydric alcohols. Ash-containing detergents include neutral alkaline earth metal salts of acidic organic compounds. Antioxidants include hindered phenols, sulfur containing compounds and alkyl diphenylamines. Lubricants include fatty acids, bright stocks, ZDDPs, ash and ash containing organophosphorus and organic sulfur compounds, boron compounds, sulfide esters, sulfide olefins, diaryl disulfides, dialkyldithiophosphate esters, ash and ash containing dialkyls Ashless and ash containing salts of dithiophosphates, ashless and ash containing dialkyldithiocarbamates, phosphate esters, complex esters and borate esters.

If the base oil is a transmission oil, the automotive lubricant composition further comprises other types of additives of known functionality in amounts of 0.1 to 30%, more preferably 0.5 to 20%, more particularly 1 to 10% of the total amount of the automotive lubricant composition. do. These additives include antioxidants, corrosion inhibitors, rust inhibitors, friction modifiers, foaming lowering agents, pour point depressants, viscosity index improvers, antiwear agents, cleaning agents, metal deactivators, extreme pressure agents, demulsifiers and mixtures thereof. Viscosity index improvers include polyisobutenes, polymethacrylate acid esters, polyacrylate acid esters, diene polymers, polyalkyl styrenes, alkenyl aryl conjugated diene copolymers and polyolefins. Examples of foam reducing agents include silicones and organic polymers. Pour point depressants include polymethacrylates, polyacrylates, polyacrylamides, condensation products of haloparaffin waxes and aromatic compounds, vinyl carboxylate polymers, dialkylfumarates, vinyl esters of fatty acids and alkyl vinyl ethers; Coalescence is mentioned. Friction modifiers include partial fatty acid esters of amides, amines, molybdenum containing compounds, and polyhydric alcohols. Ash-containing detergents include neutral and overbased alkaline earth metal salts of acidic organic compounds. Antioxidants include hindered phenols, sulfur containing compounds and alkyl diphenylamines. Examples of the antiwear agent include ZDDP, ashless and ash-containing organophosphorus and organic sulfur compounds, boron compounds, and organic molybdenum compounds. Examples of metal deactivators include benzotriazole, mercaptobenzimidazole, thiadiazole and tolutriazole derivatives. Extreme pressure agents include sulfided esters, sulfided olefins, diaryl disulfides, dialkyldithiophosphate esters, heavy metal naphthenates, ash and ash containing dialkyldithiophosphates, ash and ash containing dialkyldithiocarbamates Ashless and ash containing salts of phosphate esters, chlorinated waxes, complex esters, borate esters, and oil insoluble sheet structural compounds such as graphite and molybdenum disulfide suspensions. The demulsifiers include polyalkoxylated phenols, polyalkoxylated polyols, and polyalkoxylated polyamines.

When the base oil is a fuel, the automotive lubricant composition may contain other types of additives of known functionality in amounts of 50 ppm to 5%, more preferably 100 ppm to 3%, more particularly 150 ppm to 2% of the total amount of the automotive lubricant composition. It includes more. These additives include cetane number improvers such as isooctyl nitrate, octane number improvers such as oxygenated compounds such as methyl t-butyl ether, ashless detergents such as polyisobutylene monosuccinimide, lubricating additives, For example fatty acids and fatty acid esters, soot inhibitors such as organometallic compounds, antifoaming agents such as organosilicones, ice making additives such as glycols, low temperature operable additives such as polymer waxes, drag reducing additives, eg High molecular weight polymers, antioxidants such as hindered phenols and aromatic amines, metal deactivators such as benzotriazole, corrosion inhibitors such as imidazoline, demulsifiers and anti-haze additives such as poly Alkoxylated polyols, friction modifiers, for example fatty acid esters, emulsifiers, for example partial esters of polyols, antistatic agents, for example Recessed roll esters and mixtures thereof.

The automotive lubricant composition may further comprise a surfactant additive. Preferably the surfactant additive has at least one alkoxylated moiety or at least one ester moiety. Preferably, the surfactant additive has up to 40 carbon atoms. Particularly preferred esters are derived by reacting polyols having 2 to 8 hydroxyl groups with aliphatic, straight or branched, saturated or unsaturated monocarboxylic acids having 8 to 24 carbon atoms. Examples of particularly preferred esters include sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate and sorbitan trioleate. The weight percent of the surfactant additive to the weight percent of ashless polymer dispersant is 0.1 to 20%, preferably 1 to 15%.

Other known dispersants may be present in automotive lubricant compositions in amounts of up to 20% by weight, preferably up to 15% by weight, for example OLOA 774 sold by Chevron Oronite.

According to a further embodiment of the present invention, a base oil and 0.001 to 20% by weight ashless polymer dispersant having a number average molecular weight of 200 to 15,000, wherein the dispersant has more than one amine, alcohol, acid or halogen function Derived from reaction of a polar head group comprising a polar moiety with at least two polar tail groups, each polar tail group having from 2 to 30 monomer repeat units each comprising a hydrocarbon chain functionalized by one or more electronegative elements or moieties Disclosed is the use of an automotive lubricant composition comprising two polymer backbones in an engine, transmission or fuel supply line.

According to a further embodiment, the number average molecular weight is 200 to 15,000 and is derived from the reaction of two or more polar tail groups with polar head groups comprising polar residues having more than one amine, alcohol, acid or halogen function, Wherein each polar tail group in the engine oil, transmission oil or fuel of an ashless polymer dispersant comprising from 2 to 30 polymer backbones each comprising a monomer chain functionalized by at least one electronegative element or moiety. Discuss the use.

Dispersants for use with lubricant base oils in automotive articles have good dispersibility for dispersal of soot when used alone or in combination with other dispersants.

Dispersants provide enhanced sealant resistance as compared to currently available dispersants.

The low temperature viscosity of automotive lubricant compositions is superior to the low temperature viscosity of compositions comprising commercially available dispersants. The low temperature viscosity at −20 ° C. of the automotive lubricant composition is at most 12,000 cSt, preferably at most 10,000 cSt, in particular at most 8,000 cSt.

Automotive lubricant compositions with dispersants of the present invention have lower coefficients of friction at both 40 ° C. and 100 ° C. than compositions containing dispersants currently commercially available.

The invention will be further described with reference to the following examples only by way of example.

Example 1- Dispersant  Preparation of Examples of A1

a) Preparation of each polar tail group

1 L of a distillation rig equipped with a stirrer was charged with 60 g of industrial grade 12-hydroxystearic acid (12-HSA) at 80 ° C. under nitrogen. The temperature was then set to 190 ° C. If the temperature exceeds 125 ° C., 1.2 g tetra butyl titanate was added. When the acid number reached 35 mgKOH / g, heat was removed and the reaction cooled. The product poly-12-hydroxystearic acid was then filtered at 80 ° C.

b) Preparation of Dispersant A1

1 L of a distillation rig equipped with a stirrer was charged with 664.3 g (2.1 mol) of poly-12-hydroxystearic acid and 35.2 g (1 mol) of tetraethylene pentamine under nitrogen. The temperature was then set to 170 ° C. When the acid number reached 0.32 mgKOH / g, heat was removed and the reaction cooled.

Example 2

The ability of the ashless polymer dispersant of the invention to disperse soot deposits was measured according to the following detailed experimental procedure. An automotive lubricant composition for use in four-stroke engines containing ashless polymer dispersant A1, and 20 mg of a mixture of Vulcan XC72R carbon black (containing about 6% by weight) was used to prepare 20 stainless steel ball bearings with a diameter of 0.24 cm. The polyethylene bottle was added and shaken for 1 hour. After standing for 1 hour, the mixture was transferred to a Brookfield viscometer and the viscosity was measured using a spindle with a fixed rotational speed of 50 revolutions per minute (rpm) (read 1). Thereafter, the viscosity was measured for the vehicle lubricant composition containing no carbon black (read value 2). The increase in absolute viscosity due to the presence of carbon black was calculated as reading 1- reading 2.

The results are shown in Table 1 below. In each case, the base oil for the automotive lubricant composition is a Nexbase 3060 with a standard additive package comprising 7% ashless dispersant (C9265 from Infineum) and Nexbase 3043 (hydrogenated). Catalytic hydroisomerised and dewaxed colorless base oils) comprising high-isoparaffinic hydrocarbons. OLOA 774 is a commercially available dispersant which is a polyisobutylene succinimide sold by Chevron Oronite. This commercially available dispersant contains about 36% active dispersant. % In Table 1 is an actual addition amount of an active dispersing agent.

The results in Table 1 show that the ashless polymer dispersant according to the present invention is superior to the current commercially available product in dispersing soot particles when used in automotive lubricant compositions.

Example 3

The automotive lubricant composition disclosed in Example 2 when the amount of dispersant added was 5% by weight was subjected to a VW sealant compatibility test according to PV 3344, wherein the sealant material was AK6 elastomer. The sealant sample was immersed in the automotive lubricant composition at 150 ° C. for 94 hours. The automotive lubricant composition was replaced and the sample immersed for another 94 hours. The automotive lubricant composition was then replaced again and the sample was immersed for a third 94 hours. After the third immersion, changes in tensile strength, elongation at break, number of cracks and strength of the sealant were measured. The results are shown in Table 2 below.

The results in Table 2 show that the automotive lubricant composition according to the present invention is superior to the current commercially available products in the sealing test.

Example 4

The coefficient of friction of the automotive lubricant composition comprising 5% by weight of ashless polymer dispersant as disclosed in Example 2 was determined using a small retractor (MTM) with a steel ball on a smooth steel disc at temperatures of 40 ° C. and 100 ° C. Measured at The load applied was 36 N and the Stribeck curve of the composition was measured by varying the rotational speed from 0.01 m / s to 4 m / s. The result at the temperature of 40 degreeC is shown in following Table 3 and FIG. 1, and the result at the temperature of 100 degreeC is shown in following Table 4 and FIG.

The results in Tables 3 and 4 show that the automotive lubricant composition containing the ashless polymer dispersant according to the present invention is in the boundary, mixing and film lubrication areas at high or low temperatures as compared to automotive lubricant compositions containing dispersant products currently commercially available. Indicates a lower coefficient of friction.

Example 5

The base oil was as described in Example 2, and the viscosity of the automotive lubricant composition to which 5% of the dispersant was added was measured at −20 ° C. using an SVM3000 Statabinger viscometer. The results are shown in Table 5 below.

Claims (18)

Derived from the reaction of two or more polar tail groups with a polar average group having a number average molecular weight of 200 to 15,000 and comprising polar residues having more than one amine, alcohol, acid or halogen functional group, each polar tail group being one An ashless polymer dispersant suitable for use in automotive lubricant compositions comprising 2 to 30 polymer backbones of monomer repeat units each comprising a hydrocarbon chain functionalized by the above electronegative elements or moieties. The ashless polymer dispersant of claim 1 having a number average molecular weight of 500 to 10,000, more preferably 500 to 7,000. The ashless polymer dispersant of claim 1 or 2, wherein the polar moiety of the polar head group has more than one amine or alcohol function. 4. The ashless polymer dispersant of claim 3 wherein the polar moiety of the polar head group has 2 to 4 amine functional groups. The ashless polymer dispersant according to any one of claims 1 to 4, wherein two or more polar tail groups each have the same chemical properties. The ashless polymer dispersant according to any one of claims 1 to 5, wherein the hydrocarbon chain of two or more polar tail groups can be straight or branched and is a divalent radical containing 8 to 35 carbon atoms. 7. The hydrocarbon chain of claim 6 wherein the hydrocarbon chain is

Phosphorous ashless polymer dispersant. 8. The electronegative element or moiety of a hydrocarbon chain according to any one of claims 1 to 7, is selected from oxygen, esters (defined as -COO-) and amides (defined as -CONH-) and is in the backbone. Ashless polymer dispersant that is located or is a pendant group of monomeric repeat units. The ashless polymer dispersant of claim 8 wherein the electronegative element or moiety of the hydrocarbon chain is an ester (defined as -COO-) located in the backbone of the monomer repeat unit. 10. The ashless polymer dispersant according to claim 1, wherein the number of monomer repeat units is from 2 to 30, preferably from 2 to 20, more preferably from 3 to 15. 11. The ashless polymer dispersant according to any one of claims 1 to 10, wherein the alkyl group is derived from the polyesterification of hydroxyalkyl acid having 8 to 35 carbon atoms. The ashless polymer dispersant of claim 11 wherein the hydroxyalkyl acid is 12-hydroxystearic acid. The ashless polymer dispersant according to any one of the preceding claims, wherein the number average molecular weight is 500 to 10,000, preferably 500 to 7,000, more preferably 500 to 5,000, in particular 500 to 3,000. A base oil, and an ashless polymer dispersant having a number average molecular weight of 200 to 15,000, wherein the dispersant comprises a polar head group and at least two polar tail groups comprising a polar moiety having more than one amine, alcohol, acid or halogen functional group. Wherein each polar tail group comprises from 2 to 30 polymer backbones of monomer repeat units each comprising a hydrocarbon chain functionalized by one or more electronegative elements or moieties. 15. The vehicle lubricant composition of claim 14, further comprising 0.1 to 20% by weight of the surfactant additive, based on the weight of the ashless polymer dispersant. The vehicle lubricant composition according to claim 14 or 15, further comprising another dispersant in an amount of up to 20% by weight. Base oil, and 0.001 to 20% by weight ashless polymer dispersant having a number average molecular weight of 200 to 15,000, wherein the dispersant comprises two polar head groups comprising a polar moiety having more than one amine, alcohol, acid or halogen functional group. Derived from the reaction of the above polar tail groups, wherein each polar tail group is composed of 2 to 30 polymer backbones of monomer repeat units each comprising a hydrocarbon chain functionalized by one or more electronegative elements or moieties. Use in engines, transmissions or fuel supply lines. Derived from the reaction of two or more polar tail groups with a polar average group having a number average molecular weight of 200 to 15,000 and comprising polar residues having more than one amine, alcohol, acid or halogen functional group, each polar tail group being one Use of an ashless polymer dispersant comprising 2 to 30 polymer backbones of monomer repeat units each comprising a hydrocarbon chain functionalized by the above electronegative element or moiety in an engine oil, transmission oil or fuel.

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