Triblock copolymer concentrate for lubricating oil compositions

Abstract

To provide a class of polymers suitable for use as a viscosity index improver or viscosity modifier for a lubricant composition.SOLUTION: A VM concentrate comprises: from about 60 to about 95 parts (and at least 50 wt.%) of diluted oil (e.g., having KV100 of about 2 cSt to about 40 cSt); and from about 5 to about 40 parts (and at least 6.0 wt.%) of a linear triblock copolymer characterized by the formula: D'-PA-D'', wherein D' represents a block derived from diene, PA represents a block derived from monoalkenyl arene, D'' represents a block derived from diene, the linear triblock copolymer is present in an amount effective to modify a lubrication kinematic viscosity (KV100) at approximately 100°C of the concentrate, and the KV100 of the concentrate is about 3000 cSt or less. The linear triblock copolymers may have a thickening efficiency range of at most 0.5.SELECTED DRAWING: None

Description

[Technical field]

[0001] Disclosed herein are triblock copolymers suitable for use as viscosity modifiers / viscosity index improvers in functional fluids such as manual / automatic transmission fluids for lubricating oil compositions, including lubricating oil compositions for passenger car engines, heavy duty diesel engines, and marine diesel engines. The triblock copolymers may be present in the form of concentrates, optionally with one or more other lubricant additives, or as components in lubricating oil compositions and / or functional fluids. More specifically, certain linear triblock polymers can exhibit a particular architecture and desirable thickening efficiency (or range of thickening efficiencies in a range of base stocks), and concentrates incorporating such polymers can exhibit reasonable kinematic viscosities. [Background technology]

[0002] Lubricants used in crankcase engine oils contain components that are used to improve the engine oil's viscosity performance, i.e., to provide multigrade oils such as SAE 5W-XX and 10W-XX multigrade oils, where XX is 20, 30, or 40, or 0W-XX grade oils, where XX is 08, 12, 16, or 20. These viscosity performance enhancers, commonly referred to as viscosity index improvers (VII) or viscosity modifiers (VM), include olefin copolymers, polymethacrylates, styrene / hydrogenated diene block and star copolymers, and hydrogenated isoprene star polymers.

[0003] Olefin copolymers (or OCPs) used as viscosity index improvers traditionally comprise copolymers of ethylene, propylene, and optionally dienes, and provide good thickening effect (thickening efficiency, or TE) in hot oils. Some (co)polymers also provide excellent thickening efficiency and can be more durable in use (e.g., can exhibit a higher shear stability index). Star polymers type VII are commercially available and much research has been done to develop star polymers that provide the optimum balance of shear stability, solubility and workability, thickening efficiency, and low temperature properties. In some cases, the star polymers may contain multi-block copolymer arms to tailor certain properties. For example, U.S. Patent No. 9,133,413 describes both star polymers and linear triblock copolymer arms from which star polymers are fabricated as VII. Such triblock copolymer arms contain diene blocks having 5-35% / 65-95% by weight butadiene / isoprene (preferably 15-28% by weight butadiene). Also, U.S. Patents Nos. 4,788,361 and 5,458,792 disclose symmetric and asymmetric triblock copolymers as potential VII / VM, respectively. VII is generally provided to lubricant formulators as a concentrate, where the VII polymer is diluted with oil to allow dissolution of VII in base stock oils, among other things. Due to limited solubility in certain diluent oils, linear alkenyl arene / hydrogenated diene block copolymer VM concentrates usually have lower active polymer concentrations and present greater handling problems compared to star or olefin copolymer concentrates. Functionalization of linear alkenyl arene / hydrogenated diene block copolymers further exacerbates the diluent solubility problem. A typical linear styrene / hydrogenated diene block copolymer VM concentrate may contain as little as 3 wt. % active ingredients (AI / polymer, balance diluent oil), and higher concentrations of such polymers typically result in reduced flowability of the concentrate at the temperatures at which the lubricant is formulated. A typical multigrade crankcase lubricant formulation may require as much as 3 wt. % VM polymer, depending on the thickening efficiency (TE) of the polymer. In additive concentrates providing this amount of polymer, as much as 20% by weight of diluent oil, based on the total weight of the finished lubricant, can be incorporated.

[0004] The additive industry is highly competitive from a price perspective, with diluent oil being one of the additive manufacturer's largest raw material costs, and VM concentrates generally contain the least expensive oil available that provides suitable handling characteristics, usually a solvent neutral (SN) 100 or SN 150 Group I oil. When using such conventional VM concentrates, finished lubricant formulators must add relatively high quality base stock oils (Group II or higher) as a correcting fluid to ensure that the viscometric performance of the formulated lubricant remains within specification.

[0005] For viscosity index improving polymers, increasing the viscosity index of the polymer is one of the few factors that can tend to affect fuel economy. Viscosity index, or VI, is an empirical number that depends on the kinematic viscosity of the material measured at 40°C and 100°C, and is calculated according to ASTM D2270. A higher VI may indicate a decrease in viscosity change with temperature and may correlate with improved fuel economy performance. Specifically, a higher VI viscosity index improver may exhibit a lower kinematic viscosity at 40°C, which may result in reduced friction losses at low shear viscosity at 40°C, thereby contributing to improved fuel economy. For maximum fuel economy benefit, the viscosity index improver may provide a contribution to viscosity reduction over a range of low and high shear regimes and over the entire range of operating temperatures. Lubricant performance standards are becoming more stringent, and there is a continuing need to identify ingredients that can conveniently and cost-effectively improve overall lubricant performance. It would therefore be advantageous to be able to provide linear alkenyl arene / hydrogenated diene block copolymer VM concentrates that have increased active ingredient (polymer) concentrations, but maintain acceptable flow properties at temperatures at which lubricants are typically formulated. It would also be advantageous for such copolymers to provide a particular mixture of advantageous properties, such as formulation flexibility, thickening efficiency, viscosity index, and perhaps most importantly, the ability to thicken in concentrates without gelling, preferably relatively uniformly across different types or groups of base stocks / diluents. Summary of the Invention

[0006] According to an aspect of the present disclosure, there is provided a class of polymers suitable for use as viscosity index improvers or viscosity modifiers for lubricating oil compositions, comprising a linear triblock copolymer comprising a block derived from a monoalkenyl arene monomer (PA) located between two partially or fully hydrogenated blocks (D' and D'') derived from a diene. The VM concentrate may comprise from about 60 to about 95 parts diluent oil; and from about 5 to about 40 parts of a linear triblock copolymer characterized by the formula D'-PA-D''. The linear triblock copolymer may be present in an amount effective to adjust the lubricating kinematic viscosity at approximately 100°C (KV100) of the concentrate, the concentrate comprising at least 50 wt.% diluent oil and at least 6.0 wt.% linear triblock copolymer. Advantageously, the KV100 of the diluent oil may be from about 2 cSt to about 40 cSt, and the KV100 of the concentrate may be less than about 2000 cSt, and optionally, the concentrate may have an about 80° C. beaker pour of at least 87%, and / or a tan delta of at least 1.8. Additionally or alternatively, the present disclosure provides a VM concentrate comprising from about 60 to about 90 parts diluent oil; and from about 10 to about 40 parts linear triblock copolymer characterized by the formula D'-PA-D''. The linear triblock copolymer can be present in an amount effective to adjust the KV100 of the concentrate, the concentrate can comprise at least 50 wt.% diluent oil and at least 9.5 wt.% linear triblock copolymer. Advantageously, the KV100 of the diluent oil can be from about 2 cSt to about 40 cSt, the KV100 of the concentrate can be less than about 3000 cSt, and optionally the concentrate can have an about 80°C beaker effluent of at least 85% and / or a tan δ of at least 1.5. Further, in addition or in the alternative, the present disclosure provides a VM concentrate comprising from about 60 to about 95 parts diluent oil; and from about 5 to about 40 parts linear triblock copolymer characterized by the formula D'-PA-D''. The linear triblock copolymer can be present in an amount effective to adjust the KV100 of the concentrate, which may exhibit a thickening efficiency range of up to 0.5, and optionally an average thickening efficiency with Group III lubricants of at least 1.8. Advantageously, the KV100 of the diluent oil may be from about 2 cSt to about 40 cSt, and the KV100 of the concentrate may be less than about 2000 cSt, and optionally the concentrate may have an about 80°C beaker bleed of at least 87% and / or a tan δ of at least 1.8.

[0007] In another aspect of the present disclosure, there is provided a method for adjusting the kinematic viscosity at approximately 100° C. (KV100) of a concentrate according to one or more of the preceding aspects, comprising adding to the concentrate an effective amount of a linear triblock copolymer according to the present disclosure. In a related or separate aspect, the linear triblock copolymer according to the present disclosure may have use, for example, to control or reduce wear in an automatic or manual transmission lubricated with a composition comprising the linear triblock copolymer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The linear triblock copolymers of the present disclosure have the formula: D'-PA-D'' may be characterized by where D' represents a block derived from a diene, PA represents a block derived from a monoalkenyl arene, and D'' represents a block derived from a diene but which is typically not identical (in molecular weight, chemical composition, or both) to D'.

[0009] The VM concentrate of the present disclosure may be characterized by a lubricating kinematic viscosity (KV100) at approximately 100° C. and may include from about 60 to about 95 parts (e.g., from about 60 to about 90 parts) of diluent oil; and from about 5 to about 40 parts (e.g., from about 10 to about 40 parts) of the linear triblock copolymer of the present disclosure. The diluent oil may advantageously constitute the majority of the concentrate (i.e., the concentrate includes more than 50 wt. % of the diluent oil component). Furthermore, the linear triblock copolymer may advantageously be present in an amount effective to adjust the KV100 of the concentrate. For example, an effective amount may be an amount that allows the concentrate to include at least 5.5% by weight of the linear triblock copolymer (e.g., at least about 5.8%, at least about 6.0%, at least about 6.3%, at least about 6.5%, at least about 6.8%, at least 7.0%, at least 7.3%, at least 7.5%, at least about 7.8%, at least about 8.0%, at least about 8.3%, at least about 8.5%, at least 8.8%, at least about 9.0%, at least about 9.3%, at least about 9.5%, at least about 9.8%, at least about 10%, at least about 11%, or at least about 12% by weight). Additionally or alternatively, an effective amount may be an amount that allows the concentrate to include up to about 40% by weight of the linear triblock copolymer (e.g., up to about 38% by weight, up to about 35% by weight, up to about 33% by weight, up to about 30% by weight, up to about 28% by weight, up to about 25% by weight, up to about 23% by weight, up to about 20% by weight, up to about 18% by weight, up to about 17% by weight, up to about 16% by weight, up to about 20 ... %, up to about 15%, up to about 14%, up to about 13%, up to about 12%, up to about 11%, up to about 9.9%, up to about 9.7%, up to about 9.5%, up to about 9.3%, up to about 9.0%, up to about 8.8%, up to about 8.5%, up to about 8.3%, up to about 8.0%, up to about 7.8%, or up to about 7.5% by weight. In particular, the concentrate may comprise at least 6.0%, at least 9.5%, 5.5% to 14%, 6.0% to 14%, or 9.5% to 14% by weight of the linear triblock copolymer.

[0010] The KV100 of the concentrate containing both the diluent oil component and the linear triblock copolymer may advantageously be about 3000 cSt or less (e.g., about 2500 cSt or less, about 2000 cSt or less, about 1900 cSt or less, about 1800 cSt or less, about 1700 cSt or less, about 1600 cSt or less, about 1550 cSt or less, about 1500 cSt or less, about 1450 cSt or less, about 1400 cSt or less, about 1350 cSt or less). or lower, about 1300 cSt or lower, about 1250 cSt or lower, about 1200 cSt or lower, about 1150 cSt or lower, about 1100 cSt or lower, about 1050 cSt or lower, about 1000 cSt or lower, about 950 cSt or lower, about 900 cSt or lower, about 850 cSt or lower, about 800 cSt or lower, about 750 cSt or lower, about 700 cSt or lower, or about 650 cSt or lower). Optionally, the KV100 of the concentrate including both the diluent oil component and the linear triblock copolymer may be at least about 100 cSt (e.g., at least about 200 cSt, at least about 300 cSt, at least about 400 cSt, at least about 500 cSt, at least about 550 cSt, at least about 600 cSt, at least about 650 cSt, at least about 700 cSt, at least about 750 cSt, at least about 800 cSt, at least about 850 cSt, at least about 900 cSt, at least about 950 cSt, at least about 1000 cSt, at least about 1050 cSt, at least about 1100 cSt, at least about 1150 cSt, at least about 1200 cSt, or at least about 1250 cSt).In particular, the KV100 of the concentrate may be about 3000 cSt or less, about 2000 cSt or less, about 1600 cSt or less, 100 cSt to 3000 cSt, 100 cSt to 2000 cSt, 100 cSt to 1600 cSt, 1000 cSt to 2000 cSt, or 500 cSt to 2000 cSt.

[0011] The diene-derived D' and D'' blocks may be similar or different, but each D' and D'' individually may comprise butadiene, isoprene, and mixtures thereof. In some embodiments, the D' and D'' diene blocks may be predominantly or substantially derived from isoprene monomers. For example, the D' and D" dienes may each individually comprise at least about 85% by weight isoprene (e.g., at least about 88%, at least about 90%, at least about 92%, at least about 94% by weight at least about 96%, at least about 97%, at least about 98%, at least about 99%, at least about 99.5%, or at least about 99.9%) and / or about 14% or less by weight butadiene (e.g., about 12% or less, about 10% or less, about 8% or less, about 6% or less, about 4% or less, about 3% or less, about 2% or less, about 1% or less, about 0.5% or less, or about 0.1% or less). In such embodiments, specifically, the D' and D" dienes may each individually comprise at least about 97% by weight isoprene and / or about 3% or less by weight butadiene. Blocks D' and D'' may advantageously be hydrogenated to remove at least about 80% (e.g., at least about 85%, at least about 90%, or at least about 95%) of the polymerized diene unsaturation, and typically may be substantially or completely hydrogenated after polymerization.

[0012] In other embodiments, at least one (or in some cases each) of the diene blocks D' and D" may be a copolymer block derived from mixed diene monomers, in which from about 65% to about 95% by weight of the incorporated monomer units are derived from isoprene, from about 5% to about 35% by weight of the incorporated monomer units are derived from butadiene, and at least about 80% (or at least 90%) by weight of the butadiene are incorporated in the 1,4-configuration. In some such embodiments, at least about 15% by weight of the incorporated monomer units may be butadiene monomer units, and / or up to about 25% by weight of the incorporated monomer units may advantageously be butadiene monomer units. In such embodiments, at least one (or in some cases each) of the diene blocks D' and D" may be a random copolymer block.

[0013] The isoprene monomers used as precursors to the linear triblock copolymers of the present invention may be incorporated into the triblock copolymer in either the 1,4- or 3,4-configuration or a mixture thereof. Preferably, a majority of the isoprene (i.e., greater than 50% by weight), e.g., greater than about 60%, greater than about 70%, greater than about 80%, greater than about 90%, greater than about 95%, greater than about 97%, greater than about 98%, or greater than about 99%, up to about 100% by weight, may be incorporated into each individual block / copolymer as 1,4-units. For example, about 55% to about 100% (about 60% to about 100%, about 65% to about 100%, about 70% to about 100%, about 75% to about 100%, about 80% to about 100%, about 85% to about 100%, about 90% to about 100%, about 95% to about 100%, about 97% to about 100%, about 98% to about 100%, or about 99% to about 100%, etc.) of isoprene units may be incorporated in each individual block / copolymer in the 1,4-configuration. Excessive amounts of polybutadiene in the D' and / or D'' diene blocks, especially polybutadiene having the 1,2-configuration, may have a detrimental effect on low temperature pumpability properties.

[0014] In many embodiments, the D' and D'' blocks of the copolymer are not identical to one another in molecular weight, but may be similar or identical in composition. In certain embodiments, the D' blocks may exhibit a number average molecular weight of from about 62,000 to about 150,000 daltons (e.g., from about 63,000 to about 120,000 daltons or from about 63,000 to about 95,000 daltons) and the D'' blocks may exhibit a number average molecular weight of from about 5,000 to about 80,000 daltons (e.g., from about 20,000 to about 75,000 daltons). In another particular embodiment, the D' block may exhibit a number average molecular weight of from about 20,000 to about 60,000 daltons (e.g., from about 25,000 to about 50,000 daltons) and the D'' block may exhibit a number average molecular weight of from about 5,000 to about 40,000 daltons (e.g., from about 7,000 to about 20,000 daltons). In either or both of the above specific embodiments, the PA block may have a molecular weight of from about 8,000 daltons to about 70,000 daltons, e.g., from about 8,000 daltons to about 60,000 daltons, from about 8,000 daltons to about 50,000 daltons, from about 8,000 daltons to about 40,000 daltons, from about 8,000 daltons to about 36,000 daltons, from about 8,000 daltons to about 35,000 daltons, from about 8,000 daltons to about 30,000 daltons, from about 8,000 daltons to about 25,000 daltons, from about 10,000 daltons to about 25,000 daltons, from about 15,000 daltons to about 30,000 daltons, from about 16,000 daltons to about 35,000 daltons, from about 17,000 daltons to about 30,000 daltons, from about 18,000 daltons to about 40,000 daltons, from about 19,000 daltons to about 50,000 daltons, from about 20,000 daltons to about 55,000 daltons, from about 21,000 daltons to about 50,000 daltons, from about 22,000 daltons to about 55,000 daltons, from about 23,000 daltons to about 56,000 daltons, from about 24,000 000 Daltons to about 70,000 Daltons, about 10,000 Daltons to about 60,000 Daltons, about 10,000 Daltons to about 50,000 Daltons, about 10,000 Daltons to about 40,000 Daltons, about 10,000 Daltons to about 36,000 Daltons, about 10,000 Daltons to about 35,000 Daltons, about 10,000 Daltons to about 30,000 Daltons, about 10,000 Daltons to about 25,000 Daltons, about 15,000 Daltons to about 70,000 Daltons, about 15,000 Daltons to about 50,000 Daltons, about 15,000 Daltons to about 60,000 Daltons, about 15,000 Daltons to about 70,000 Daltons, about 15,000 Daltons to about 80,000 Daltons, about 15,000 Daltons to about 90,000 Daltons, about 15,000 Daltons to about 10 ... from about 10,000 daltons to about 60,000 daltons, from about 15,000 daltons to about 50,000 daltons, from about 15,000 daltons to about 40,000 daltons, from about 15,000 daltons to about 36,000 daltons, from about 15,000 daltons to about 35,000 daltons, from about 15,000 daltons to about 30,000 daltons, from about 15,000 daltons to about 25,000 daltons, from about 20,000 daltons to about 70,000 daltons, from about 20,000 daltons to about 60,000 daltons, from about 20,000 daltons to about 70,000 daltons, from about 20,000 daltons to about 80,000 daltons, from about 20,000 daltons to about 90,000 daltons, from about 20,000 daltons to about 100,000 daltons, from about 20,000 daltons to about 110,000 daltons, from about 20,000 daltons to about 120,000 daltons, from about 20,000 daltons to about 130,000 daltons, from about 20,000 daltons to about 140,000 daltons, from about 20,000 daltons to about 150,000 daltons, from about 20,000 daltons to about 160 from about 20,000 daltons to about 50,000 daltons, from about 20,000 daltons to about 40,000 daltons, from about 20,000 daltons to about 36,000 daltons, from about 20,000 daltons to about 35,000 daltons, from about 20,000 daltons to about 30,000 daltons, from about 20,000 daltons to about 25,000 daltons, from about 25,000 daltons to about 70,000 daltons, from about 25,000 daltons to about 60,000 daltons, from about 25,000 daltons to about 50,000 daltons, from about 25,000 daltons to about 40,The PA block may exhibit a number average molecular weight of from about 10,000 daltons to about 40,000 daltons, from about 15,000 daltons to about 35,000 daltons, from about 15,000 daltons to about 50,000 daltons, or from about 20,000 daltons to about 36,000 daltons.

[0015] Additionally or alternatively, in linear triblock copolymers according to the present disclosure, the ratio of the PA block number average molecular weight to the sum of the D'+D'' block number average molecular weights may be from about 0.25 to about 0.50, e.g., from about 0.25 to about 0.45, from about 0.25 to about 0.40, from about 0.25 to about 0.35, from about 0.25 to about 0.30, from about 0.30 to about 0.50, from about 0.30 to about 0.45, from about 0.30 to about 0.40, from about 0.30 to about 0.35, from about 0.35 to about 0.50, from about 0.35 to about 0.45, from about 0.35 to about 0.40, from about 0.40 to about 0.50, from about 0.40 to about 0.45, or from about 0.45 to about 0.50.

[0016] Additionally or alternatively, in linear triblock copolymers according to the present disclosure, there may be a relationship between the number average molecular weights of the diene blocks. For example, in embodiments, the ratio of the number average molecular weight of the D' block to the number average molecular weight of the D" block may be greater than 1.00:1, up to about 1.25:1. However, in other embodiments, the ratio of the number average molecular weight of the D' block to the number average molecular weight of the D" block may be from about 1.4:1 to about 3.0:1. In yet other embodiments, the ratio of the number average molecular weight of the D' block to the number average molecular weight of the D" block may be from about 6.0:1 to about 30:1. The term "number average molecular weight", as used herein, should be understood to refer to number average molecular weight measured by gel permeation chromatography (also known as "GPC", or "SEC") using relatively monodisperse polystyrene standards with tetrahydrofuran (THF) eluent at approximately 40° C. Molecular weights (e.g., number average molecular weights) of diene blocks D' and D'' are reported herein as measured prior to any hydrogenation that may be performed after polymerization.

[0017] Suitable monoalkenyl arene monomers include monovinyl aromatic compounds such as styrene, monovinyl naphthylene, and their alkylated derivatives such as o-, m-, and p-methylstyrene, alpha-methylstyrene, ethylstyrene (especially p-ethylstyrene), propylstyrene (especially p-isopropylstyrene), and tertiary butylstyrene (especially para-t-butylstyrene). In particular, the monoalkenyl arene may comprise or be styrene.

[0018] The linear triblock copolymers of the present disclosure may have a total number average molecular weight (additive combination of the number average molecular weights of the D', PA, and D'' blocks) of from about 25,000 to about 1,000,000 daltons, for example, from about 40,000 to about 500,000 daltons, or from about 50,000 to about 200,000 daltons. For example, the linear triblock copolymers of the present disclosure can be formed as living polymers by anionic polymerization in solution in the presence of an anionic initiator, as described in US Patents RE27,145 and RE4,116,917. Exemplary initiators can include or be (mono)lithium hydrocarbons. Suitable lithium hydrocarbons can include unsaturated compounds such as allyllithium, methallyllithium, aromatic compounds such as phenyllithium, tolyllithium, xylyllithium, and naphthyllithium, and alkyllithiums such as methyllithium, ethyllithium, propyllithium, butyllithium, amyllithium, hexyllithium, 2-ethylhexyllithium, and n-ethylhexyllithium, among others. In particular, the initiator can include or be sec-butyllithium. The initiator can be added to the polymerization mixture in two or more stages, optionally with additional monomers. The linear triblock copolymers of the present disclosure can be, and preferably may be, prepared by stepwise polymerization of monomers, for example, by polymerizing one of the two diene blocks, followed by addition of the other monomer (specifically including or being a monoalkenyl arene monomer), followed by polymerization of the second of the two diene blocks to form a living polymer having the formula: polydiene block-poly(alkenyl arene) block-polydiene block.

[0019] Either or both of D' and D'' are desirably random diene copolymers, such as polyisoprene / polybutadiene copolymers, and the living polydiene copolymer block will not be a random copolymer, as described in U.S. Pat. No. 7,163,913, in the absence of proper polymerization control, but will instead contain a polybutadiene block, a tapered segment containing both butadiene and isoprene addition products, and a polyisoprene block. To prepare a random copolymer, the more reactive butadiene monomer may be gradually added to the polymerization reaction mixture containing the less reactive isoprene, such that the molar ratio of the monomers in the polymerization mixture is maintained at the required level. It is also possible to achieve the required randomization by gradually adding to the polymerization mixture a mixture of the monomers to be copolymerized. Living random copolymers can also be prepared by carrying out the polymerization in the presence of so-called randomizing agents. The randomizing agent may include or be a polar compound that does not substantially inactivate the polymerization process and tends to randomize the manner in which the monomers are incorporated into the polymer chain. Suitable randomizers include, but are not necessarily limited to, tertiary amines such as trimethylamine, triethylamine, dimethylamine, tri-n-propylamine, tri-n-butylamine, dimethylaniline, pyridine, quinoline, N-ethyl-piperidine, N-methylmorpholine, etc.; thioethers such as dimethylsulfide, diethylsulfide, di-n-propylsulfide, di-n-butylsulfide, methylethylsulfide, etc.; and ethers such as dimethylether, methylether, diethylether, di-n-propylether, di-n-butylether, di-octylether, di-benzylether, di-phenylether, anisole, 1,2-dimethyloxyethane, o-dimethyloxybenzene, and cyclic ethers such as tetrahydrofuran, among others.

[0020] Even with controlled monomer addition and / or the use of randomizers, the beginning and end portions of the polymer chain may have more than "random" amounts of polymer derived from more and less reactive monomers, respectively. Thus, for purposes of the present invention, the term "random copolymer" refers to polymer chains or blocks the vast majority of which (e.g., greater than 80%, such as greater than 90% or greater than 95%) result from random addition of comonomer material.

[0021] Solvents in which living polymers can be formed can include relatively inert liquid solvents such as hydrocarbons, e.g., aliphatic hydrocarbons such as pentane, hexane, heptane, octane, 2-ethylhexane, nonane, decane, cyclohexane, methylcyclohexane, and the like, or combinations thereof, and / or aromatic hydrocarbons, e.g., benzene, toluene, ethylbenzene, xylene, diethylbenzene, propylbenzene, and the like, or combinations thereof. Cyclohexane is particularly exemplary. Additionally or alternatively, mixtures of hydrocarbons, e.g., lubricating oils, can be used. The temperature at which the living polymerization is carried out may vary within a wide range, such as from about 20° C. to about 80° C., such as from about −50° C. to about 150° C. The reaction may suitably be carried out under a relatively inert atmosphere, such as under nitrogen, and may optionally be carried out under pressure, for example from about 0.5 bar to about 10 bar. The concentration of initiator used to prepare the living polymer may also vary within wide limits and may be advantageously guided by the desired molecular weight of the living polymer.

[0022] The resulting linear block copolymer can then be hydrogenated using any suitable means. Hydrogenation catalysts, such as copper or molybdenum compounds, may be used. In addition or instead, catalysts containing precious metals or precious metal-containing compounds may be used. Exemplary hydrogenation catalysts include non-precious metals or non-precious metal-containing compounds of Group VIII of the Periodic Table of Elements, such as iron, cobalt, and / or nickel, among others. Specific but non-exclusive examples of hydrogenation catalysts include Raney nickel and nickel-loaded diatomaceous earth. Particularly suitable hydrogenation catalysts may be those obtained by reacting a metal hydrocarbyl compound with any of the organic compounds of Group VIII metals iron, cobalt, and / or nickel, the latter compounds comprising at least one organic compound attached to the metal atom via an oxygen atom, as described, for example, in GB 1,030,306. In some circumstances, preference may be given to hydrogenation catalysts obtained by reacting aluminum trialkyls (e.g. aluminum triethyl (Al(Et3)) or aluminum triisobutyl) with nickel salts of organic acids (e.g. nickel diisopropyl salicylate, nickel naphthenate, nickel 2-ethylhexanoate, nickel di-tert-butylbenzoate, nickel salts of saturated monocarboxylic acids obtained by reacting olefins having from 4 to 20 carbon atoms in the molecule with carbon monoxide and water in the presence of an acid catalyst, etc.) or nickel enolates or phenolates (e.g. nickel acet(on)ylacetonate, nickel salts of butylacetophenone, etc.). Suitable hydrogenation catalysts should be well known to those skilled in the art, and the above list is not necessarily intended to be exhaustive.

[0023] The hydrogenation of the block copolymer of the present disclosure can be suitably carried out in a solution, such as, for example, a solvent that is relatively or substantially inert during the hydrogenation reaction. Saturated hydrocarbons and / or mixtures of saturated hydrocarbons can be suitable solvents. Advantageously, the hydrogenation solvent can be the same as the solvent in which the polymerization is carried out, or can be miscible with the solvent in which the polymerization is carried out (e.g., contains the same component or components as in the polymerization solvent). Typically, when a hydrogenation process is carried out, at least 50 mol% of the original olefinic unsaturation, for example, at least 70 mol%, at least 80 mol%, at least 90 mol%, at least 95 mol%, at least 99 mol%, at least 99.5 mol%, at least 99.9 mol%, or substantially all of the original olefinic unsaturation can be hydrogenated in the process.

[0024] In addition or alternatively, the linear block copolymer of the present disclosure can be selectively hydrogenated such that the olefin saturation is hydrogenated as described above, but the aromatic unsaturation is hydrogenated to a lesser extent. In some embodiments, less than 15% (e.g., less than 10% or less than 5%) of the aromatic unsaturation may be hydrogenated during the process. Selective hydrogenation techniques are also well known to those skilled in the art and are described, for example, in U.S. Pat. Nos. 3,595,942, RE27,145, and 5,166,277. The polymer can then be recovered from the solvent in which it was hydrogenated by any convenient means, such as by evaporating the solvent, for example, as a solid or in concentrated liquid form. Alternatively, an extractant such as oil (e.g., lubricating oil) can be added to the solution and the solvent removed from the mixture so formed to provide a concentrate. A suitable concentrate may contain from about 3% to about 25% by weight (e.g., from about 5% to about 23% by weight, from about 6% to about 20% by weight, from about 6.5% to about 20% by weight, or from about 6.5% to about 15% by weight, among others).

[0025] The linear triblock copolymers of the present disclosure can be advantageously used in formulating lubricating oil compositions, for example, for crankcases, for passenger car engines and heavy-duty diesel engines, as well as in formulating manual and / or automatic transmission fluids. The lubricating oil composition can advantageously include a concentrate of the linear triblock copolymer and a diluent oil component of lubricating viscosity, and optionally other additives necessary to provide the lubricating oil composition / transmission fluid composition with the required properties, and the amount of VM concentrate and / or the concentrated amount of the linear triblock copolymer is desirably effective to adjust the viscosity index of the lubricating oil composition. For example, after dilution from the concentrated form for the relevant application, the lubricating oil composition and transmission fluid composition can include the linear block copolymer of the present disclosure in an amount of about 0.1% to about 2.5% by weight, for example, about 0.3% to about 1.5% by weight, or about 0.4% to about 1.3% by weight, expressed as the mass percent of active ingredient (AI) in the fully formulated lubricating oil composition / transmission fluid composition. The linear triblock copolymers of the present disclosure may contain the sole VI improver (or VM) or may be used in combination with other VI improvers, including, for example, polyisobutylene, copolymers of ethylene and propylene (OCP), polymethacrylates, methacrylate copolymers, copolymers of unsaturated dicarboxylic acids and vinyl compounds, interpolymers of styrene and acrylic esters, and hydrogenated copolymers of styrene / isoprene, styrene / butadiene, and other hydrogenated isoprene / butadiene copolymers, and partially hydrogenated homopolymers of butadiene and isoprene. The linear triblock copolymers according to the present disclosure can advantageously exhibit relatively similar thickening efficiencies across a range of different types or groups of diluent oil base stocks, such as by exhibiting a relatively low thickening efficiency (TE) range. As defined below, the TE range measurement typically involves measuring the thickening efficiency of the linear triblock copolymer in at least three (preferably at least four) types of reference oils, or at least one reference oil in at least three groups of reference oils (e.g., at least Group II oils, Group III oils, and Group IV oils). In particular, four different types of reference oils can be used across three groups: "standard" Group III oils (e.g., natural base stocks); "non-standard" Group III oils (e.g., synthetic GTL base stocks); Group II oils; and Group IV oils. In particular, the TE range of the linear triblock copolymer may advantageously be up to 0.5 or up to 0.4, but optionally and preferably, the linear block copolymer according to the present disclosure further exhibits an average Group III thickening efficiency (i.e., a simple number average of the thickening efficiencies in "standard" and "non-standard" Group III base stocks, if applicable) of at least 1.7 or at least 1.8. Additionally or alternatively, the viscosity index (grams of linear block copolymer per 100 grams of base stock) of a 1% by weight solution of the linear triblock copolymer in Group II base stock may be 165 or less, 150 or less, or 140 or less (e.g., at least 90).

[0026] Optionally but preferably, linear triblock copolymers according to the present disclosure can advantageously exhibit flowability, especially in the form of concentrates. The beaker spill test indicates the relative amount (mass) of VM concentrate that flows out of a beaker in a proscribed period of time. The Tan δ test indicates the relative viscoelastic response of the composition / concentrate, which can indicate flowability or lack thereof in the case of flowable samples. Thus, in addition to having a suitably low KV100, the linear triblock copolymer concentrate may exhibit an about 80° C. beaker bleed of at least 80% (e.g., at least 83%, at least 85%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, or at least 95%; optionally, up to 99% or up to 98%), as well as a tan δ(G″ / G′) of at least 1.0 (e.g., at least 1.3, at least 1.5, at least 1.7, at least 1.8, at least 1.9, at least 2.0, at least 2.2, at least 2.4, at least 2.6, at least 2.8, at least 3.0, at least 3.5, at least 4.0, at least 4.5, or at least 5.0; optionally, up to 50, up to 30, or up to 20).

[0027] The diluent oil component of lubricating viscosity useful in the context of the lubricating oil composition of the present disclosure can be selected from natural lubricating oils, synthetic lubricating oils, and mixtures thereof. The diluent oil component may range in viscosity from light distillate mineral oils to heavy lubricating oils, such as gasoline engine oils, mineral lubricating oils, and heavy duty diesel oils. In general, the (kinematic) viscosity of the diluent oil component may range from about 2 cSt to about 40 cSt, particularly from about 4 cSt to about 20 cSt, measured at about 100° C., i.e., before adding thereto the linear block copolymer to form the lubricating oil composition according to the present disclosure. Natural oil components can include animal oils, vegetable oils (e.g., castor oil, lard oil, etc.), liquid petroleum-based oils, and hydrorefined, solvent-treated, or acid-treated mineral oils of the paraffinic, naphthenic, and mixed paraffinic-naphthenic types, and combinations thereof. Additionally or alternatively, oils of lubricating viscosity derived from coal or shale serve as useful oil components according to the present disclosure. The synthetic oil component can include hydrocarbon oils and halo-substituted hydrocarbon oils such as polymerized and copolymerized olefins (e.g., polybutylene, polypropylene, propylene-isobutylene copolymers, chlorinated polybutylene, poly(1-hexene), poly(1-octene), poly(1-decene)); alkylbenzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, di(2-ethylhexyl)benzene); polyphenyls (e.g., biphenyl, terphenyl, alkylated polyphenols); and alkylated diphenyl ethers and alkylated diphenyl sulfides, as well as derivatives, analogs, homologs, copolymers, and combinations thereof.

[0028] Alkylene oxide polymers and interpolymers and their derivatives in which the terminal hydroxyl groups have been modified by esterification, etherification, etc., constitute another class of known synthetic lubricating oils. These are exemplified by polyoxyalkylene polymers prepared by polymerization of ethylene and / or propylene oxide, alkyl and / or aryl ethers of polyoxyalkylene polymers (e.g., methyl-polyisopropylene glycol ether having a (number average) molecular weight of about 1000 or diphenyl ethers of poly-ethylene glycol having a (number average) molecular weight of about 1000 to about 1500), and / or their mono- and poly-carboxylic acid esters, e.g., acetate esters, mixed C3-C8 fatty acid esters, and C13 oxo acid diesters of tetraethylene glycol.

[0029] Another suitable class of synthetic oil components comprises the esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl and alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acids, alkenyl malonic acids) with any of a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol). Specific examples of such esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, and the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid. Additional or alternative esters that may be useful as synthetic oil components include C5-C 12 Included may be those made from monocarboxylic acids and polyols, as well as polyol esters such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, and tripentaerythritol. Silicon-based oils, such as polyalkyl-, polyaryl-, polyalkoxy-, or polyaryloxy-silicone oils and silicate oils, comprise another useful class of synthetic oil components. Such oils can include tetraethyl silicate, tetraisopropyl silicate, tetra-(2-ethylhexyl) silicate, tetra-(4-methyl-2-ethylhexyl) silicate, tetra-(p-tert-butyl-phenyl) silicate, hexa-(4-methyl-2-ethylhexyl) disiloxane, poly(methyl) siloxane, poly(methyl-phenyl) siloxane, and combinations thereof. Other additional or alternative synthetic oil components can include liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, diethyl ester of decylphosphonic acid) and polymeric tetrahydrofuran.

[0030] A VM concentrate according to the present disclosure may consist essentially of (or may consist of) a linear triblock copolymer according to the present disclosure, a diluent oil, and optionally a pour point depressant. However, if the VM concentrate includes more than these components, it may advantageously include one or more lubricating oil composition additives, such as, but not necessarily limited to, a dispersant (e.g., an ashless dispersant), a surfactant, an antiwear agent, an antioxidant, a corrosion inhibitor, a friction modifier, an antifoam agent, a seal-swelling control agent, or combinations thereof. Alternatively, a VM concentrate containing such combinations of additives may be referred to as an additive concentrate (or addpack). The concentrate can use 5% to 25% (e.g., 5% to 18% or 10% to 15% by weight) of linear triblock copolymer, before or after the addition of any additives, or regardless of any other additives, and 75% to 95% (e.g., 82% to 95% or 85% to 90% by weight) of diluent oil. A lubricating oil composition containing a linear triblock copolymer according to this disclosure, either by itself or as a VM concentrate according to this disclosure, may also contain similar additives or add packs. Pour point depressants, otherwise known as lube oil flow improvers (LOFIs), lower the minimum temperature at which the fluid will flow or can be flowed. Such additives are well known. Typical of such additives that can improve the low temperature fluidity of a fluid are C8-C 18 Dialkyl fumarate / vinyl acetate copolymers, polymethacrylates, and combinations thereof. Ashless dispersants promote the suspension of oil insoluble matter that typically results from oxidation of the lubricating oil composition during wear or combustion, and are particularly advantageous in preventing sludge deposition and varnish formation, especially in gasoline engines.

[0031] Metal-containing or ash-forming surfactants function as both deposit reducing or enhancing surfactants and acid neutralizers / rust inhibitors, thereby reducing wear and corrosion and extending engine life. Surfactants generally comprise a polar head with a long hydrophobic tail, which comprises a metal salt of an acidic organic compound. The salt may contain a substantially stoichiometric amount of the metal, in which case the salt will usually be described as a normal or neutral salt and will typically have a total base number or TBN (which can be measured by ASTM D2896) of 0 to 80. Large amounts of metal base can be incorporated by reacting an excess of a metal compound (e.g., oxide or hydroxide) with an acid gas (e.g., carbon dioxide). The resulting overbased surfactant may include a neutralizing surfactant as the outer layer of the metal base (e.g., carbonate) micelle. Such overbased surfactants may have a TBN of 150 or higher, and typically from 250 to 450 or higher.

[0032] Dihydrocarbyl metal dithiophosphate salts are frequently used as antiwear and antioxidant agents in lubricating oil compositions. The metal may be an alkali or alkaline earth metal, or aluminum, lead, tin, molybdenum, manganese, nickel, or copper. Zinc salts are most commonly used in lubricating oils and can be prepared according to known techniques, for example, by first forming a dihydrocarbyl dithiophosphate (DDPA), usually by reacting one or more alcohols or phenols with P2S5, and then neutralizing the DDPA formed with a zinc compound. For example, a dithiophosphoric acid can be made by reacting a mixture of primary and secondary alcohols. Alternatively, multiple dithiophosphoric acids can be prepared in which the hydrocarbyl groups on one side are entirely secondary in character and the hydrocarbyl groups on the other are entirely primary in character. Any basic or neutral zinc compound can be used to make the zinc salts, but oxides, hydroxides, and carbonates are most commonly used. Commercially available additives often contain an excess of zinc, due to the use of an excess of basic zinc compound in the neutralization reaction. Antioxidants or antioxidants reduce the tendency of lubricating oil compositions to deteriorate during use. Deterioration due to oxidation may be evident by sludge in the lubricant, varnish-like deposits on metal surfaces, and by viscosity increase. Such antioxidants include, but are not necessarily limited to, hindered phenols, C5-C 12 Included among these are alkaline earth metal salts of alkylphenol thioesters having alkyl side chains, calcium nonylphenol sulfide, oil-soluble phenates and sulfurized phenates, phosphorus sulfurized hydrocarbons or sulfurized hydrocarbons, phosphorus esters, metal thiocarbamates, oil-soluble copper compounds as described in U.S. Pat. No. 4,867,890, molybdenum-containing compounds, and aromatic amines, as well as combinations and / or reaction products thereof.

[0033] Known friction modifiers include oil-soluble organomolybdenum compounds.These organomolybdenum friction modifiers can also provide antioxidant and antiwear properties to lubricating oil compositions.Examples of such oil-soluble organomolybdenum compounds include dithiocarbamate, dithiophosphate, dithiophosphinate, xanthate, thioxanthate, and sulfide, and mixtures thereof.Specific examples include molybdenum dithiocarbamate, dialkyldithiophosphate, alkylxanthate, alkylthioxanthate, and combinations thereof.

[0034] Other known friction modifiers that may additionally or alternatively be present in the lubricating oil compositions according to the present disclosure include: glyceryl monoesters of higher fatty acids, such as glyceryl monooleate; esters of long chain polycarboxylic acids and diols, such as butanediol esters of dimerized unsaturated fatty acids; oxazoline compounds; alkoxylated alkyl substituted monoamines, diamines, and alkyl ether amines, such as ethoxylated tallow amines, and ethoxylated tallow ether amines; and combinations thereof. Foam control in lubricating oil compositions can be provided by polysiloxane type antifoam agents, such as silicone oils and / or polydimethylsiloxanes. Some of the additives mentioned above can provide multiple benefits, so for example a single additive may act as a dispersant-antioxidant, this approach is well known and need not be further described here. It may also be necessary to include additives that maintain the stability of the viscosity of the formulation / composition.Thus, polar group-containing additives can achieve a suitable low viscosity at the pre-formulation stage, but it has been observed that some compositions may "age" or increase in viscosity when stored for extended periods.Additives that are typically effective in controlling this viscosity increase / aging phenomenon include long chain hydrocarbons functionalized by reaction with mono- / di-carboxylic acids and / or anhydrides used in the preparation of ashless dispersants, as disclosed above.

[0035] Representative effective amounts of such additional additives when used in (crankcase) lubricating oil compositions according to this disclosure are listed below. [Table 1]

[0036] Additionally or alternatively, the present disclosure may include one or more of the following embodiments. Embodiment 1. A viscosity modifier (VM) concentrate comprising: from about 60 to about 95 parts diluent oil; and from about 5 to about 40 parts linear triblock copolymer characterized by the formula D'-PA-D'', where D' represents a block derived from a diene, PA represents a block derived from a monoalkenyl arene (e.g., styrene or styrene monomer), and D'' represents a block derived from a diene, the linear triblock copolymer adjusting the lubricating kinematic viscosity at approximately 100°C (KV100) of the concentrate. and the concentrate comprises at least 50 wt.% diluent oil, the effective amount of linear triblock copolymer is such that the concentrate comprises at least 6.0 wt.% linear triblock copolymer, the diluent oil has a KV100 of from about 2 cSt to about 40 cSt, the concentrate has a KV100 of about 3000 cSt or less, or about 2000 cSt or less, and has an about 80° C. beaker bleed of at least 87%, and / or a tan delta of at least 1.8.

[0037] Embodiment 2. The concentrate of embodiment 1, comprising from 6.0% to about 13% by weight of the linear triblock copolymer. Embodiment 3. The concentrate of embodiment 1 or 2, wherein the concentrate has a KV100 of about 1000 cSt or less. Embodiment 4. The concentrate of any one of embodiments 1 to 3, wherein D' has a number average molecular weight of from about 62,000 Daltons to about 150,000 Daltons, PA has a number average molecular weight of from about 15,000 Daltons to about 50,000 Daltons, and D'' has a number average molecular weight of from about 5,000 to about 80,000 Daltons.

[0038] Embodiment 5. The concentrate of any one of embodiments 1 to 4, wherein (i) D' has a number average molecular weight of from about 63,000 Daltons to about 95,000 Daltons, (ii) PA has a number average molecular weight of from about 20,000 Daltons to about 36,000 Daltons, or (iii) both (i) and (ii). Embodiment 6. A VM concentrate comprising: from about 60 to about 90 parts diluent oil; and from about 10 to about 40 parts linear triblock copolymer characterized by the formula D'-PA-D'', where D' represents a block derived from a diene, PA represents a block derived from a monoalkenyl arene, and D'' represents a block derived from a diene, the linear triblock copolymer being present in an amount effective to adjust the lubricating kinematic viscosity at approximately 100°C (KV100) of the concentrate, and the concentrate having a viscosity of at least 50 mass %. % by weight of diluent oil, an effective amount of linear triblock copolymer is an amount in which the concentrate contains at least 9.5% by weight (e.g., from 9.5% to 14% by weight) of linear triblock copolymer, the KV100 of the diluent oil is from about 2 cSt to about 40 cSt, and the KV100 of the concentrate is about 3000 cSt or less, or about 2000 cSt or less, optionally with at least 85% at about 80° C. beaker bleed and / or a tan δ of at least 1.5.

[0039] Embodiment 7. The concentrate of embodiment 6, wherein the KV100 of the concentrate is from about 1000 cSt to about 2000 cSt. Embodiment 8. The concentrate of embodiment 6 or embodiment 7, wherein D' has a number average molecular weight of from about 20,000 Daltons to about 60,000 Daltons, PA has a number average molecular weight of from about 10,000 Daltons to about 40,000 Daltons, and D'' has a number average molecular weight of from about 5,000 to about 40,000 Daltons. Embodiment 9. The concentrate of any one of embodiments 6 to 8, which satisfies one or more of the following: (i) D' has a number average molecular weight of from about 25,000 Daltons to about 50,000 Daltons; (ii) PA has a number average molecular weight of from about 15,000 Daltons to about 35,000 Daltons; and (iii) D'' has a number average molecular weight of from about 7,000 to about 20,000 Daltons. Embodiment 10. The concentrate of any one of embodiments 6 to 9, wherein the ratio of the number average molecular weight of D' to the number average molecular weight of D'' is from about 1.4:1 to about 3.0:1, or from about 6.00:1 to about 20.0:1. Embodiment 11. A VM concentrate comprising: from about 60 to about 95 parts diluent oil; and from about 5 to about 40 parts linear triblock copolymer characterized by the formula D'-PA-D'', where D' represents a block derived from a diene, PA represents a block derived from a monoalkenyl arene, and D'' represents a block derived from a diene, the linear triblock copolymer exhibits a thickening efficiency range of up to 0.5 and is present in an amount effective to adjust the lubricating kinematic viscosity (KV100) of the concentrate at about 100°C, the concentrate comprising at least 50 wt.% diluent oil, the KV100 of the diluent oil being from about 2 cSt to about 40 cSt, and the KV100 of the concentrate being about 3000 cSt or less, or about 2000 cSt or less.

[0040] Embodiment 12. The concentrate of embodiment 11, wherein the effective amount of linear triblock copolymer is such that the concentrate contains from 6.0% to 14% by weight of linear triblock copolymer. Embodiment 13. The concentrate of embodiment 11 or embodiment 12, wherein D' has a number average molecular weight of from about 30,000 Daltons to about 95,000 Daltons, PA has a number average molecular weight of from about 20,000 Daltons to about 35,000 Daltons, and D" has a number average molecular weight of from about 1,800 to about 60,000 Daltons, and the ratio of the number average molecular weight of D' to the number average molecular weight of D" is from about 1.0:1 to about 30:1. Embodiment 14. The concentrate of any one of embodiments 1-13, wherein the lubricating oil composition has a KV100 of from about 100 cSt to about 1600 cSt.

[0041] Embodiment 15. The concentrate of any one of embodiments 1-14, wherein the D' and D'' dienes each individually comprise butadiene, isoprene, and mixtures thereof, but are not identical to one another, and the D' and D'' blocks are substantially hydrogenated after polymerization. Embodiment 16. The concentrate of any one of embodiments 1-15, wherein the D' and D'' dienes each individually comprise: (i) about 3% by weight or less of butadiene; (ii) at least about 97% by weight of isoprene; or (iii) both (i) and (ii). Embodiment 17. The concentrate of any one of embodiments 1 to 16, wherein the ratio of the PA number average molecular weight to the sum of the D'+D'' number average molecular weight is from about 0.25 to about 0.50. Embodiment 18. The concentrate of any one of embodiments 1 to 17, wherein the ratio of the number average molecular weight of D' to the number average molecular weight of D'' is greater than 1.00:1 and up to about 1.25:1, or from about 1.4:1 to about 3.0:1, or from about 6.00:1 to about 20.0:1.

[0042] Embodiment 19. The concentrate of any one of embodiments 1-18, wherein the diluent oil comprises a Group II, Group III, and / or Group IV base stock, such as a Group II and / or Group III base stock. Embodiment 20. The concentrate of any one of embodiments 1-19, further comprising one or more of an ashless dispersant, a surfactant, an antiwear agent, an antioxidant, a corrosion inhibitor, a friction modifier, an antifoam agent, a seal swell control agent, or combinations thereof. Embodiment 21. A method for adjusting the kinematic viscosity at approximately 100°C (KV100) of the VM concentrate of any one of embodiments 1-5 and 14-20, comprising adding to the concentrate an effective amount of a linear triblock copolymer characterized by the formula D'-PA-D'', where D' represents a block derived from a diene, PA represents a block derived from a monoalkenyl arene, and D'' represents a block derived from a diene, wherein the effective amount of the linear triblock copolymer constitutes at least 6.0% by weight of the concentrate, and wherein the KV100 of the concentrate is about 3000 cSt or less, or about 2000 cSt or less. Embodiment 22. A method for adjusting the kinematic viscosity at approximately 100°C (KV100) of the concentrate of any one of embodiments 6-10 and 14-20, comprising adding to the concentrate an effective amount of a linear triblock copolymer characterized by the formula D'-PA-D'', where D' represents a block derived from a diene, PA represents a block derived from a monoalkenyl arene, and D'' represents a block derived from a diene, wherein the effective amount of the linear triblock copolymer constitutes at least 9.5% by weight of the concentrate, and wherein the KV100 of the concentrate is about 3000 cSt or less, or about 2000 cSt or less.

[0043] Embodiment 23. A method for adjusting the kinematic viscosity at approximately 100°C (KV100) of the VM concentrate of any one of embodiments 11 to 20, comprising adding to the concentrate an effective amount of a linear triblock copolymer characterized by the formula D'-PA-D'', where D' represents a block derived from a diene, PA represents a block derived from a monoalkenyl arene, and D'' represents a block derived from a diene, the linear triblock copolymer exhibits a thickening efficiency range of up to 0.5, and the KV100 of the concentrate comprising the effective amount of the linear triblock copolymer is about 3000 cSt or less, or about 2000 cSt or less. Embodiment 24. Use of a VM concentrate having an adjusted KV100 according to any one of embodiments 1 to 20 to control or reduce wear in an automatic or manual transmission lubricated with a lubricating oil composition comprising the VM concentrate. EXAMPLES

[0044] The present invention can be further understood by reference to the following (non-limiting) examples, in which the properties of certain components or the composition itself are described using certain terms of the art as defined below. In the examples, all parts are by weight unless otherwise stated.

[0045] "Shear Stability Index (SSI)" is a measure of the ability of a polymeric component in a crankcase lubricant to maintain its thickening capability during shear conditions, and typically indicates the resistance of the polymer to degradation under use conditions. The higher the SSI, the less stable the polymer is, i.e., the more susceptible it is to degradation. SSI is defined as the percentage of viscosity loss attributable to the polymer and is calculated as follows:

number

[0046] "Thickening efficiency (TE)" refers to the oil thickening capacity of a polymer per unit mass and is defined as follows:

number

[0047] where c is the polymer concentration (grams of polymer / 100 grams of solution) and kv oil+polymer is the kinematic viscosity of the polymer in the reference oil, and kv oil is the kinematic viscosity of the reference oil. In most cases, TE is measured at approximately 1% by weight in the reference oil, as in the examples below. "Thickening efficiency range" (TE range) refers to the relative uniformity of the thickening efficiency (TE) of a polymer across a series of different types or groups of reference oils, that is, including at least three (preferably at least four) types of reference oils, or including at least one reference oil from at least three groups of reference oils (e.g., at least Group II oils, Group III oils, and Group IV oils). In particular, four different types of reference oils can be used across three groups: "standard" Group III oils (e.g., natural base stocks); "non-standard" Group III oils (e.g., synthetic GTL base stocks); Group II oils; and Group IV oils. In this disclosure, the TE range is evaluated at approximately the same concentration in each of the different reference oils, for example, at a polymer concentration of about 1 wt.%. The TE range is represented by the absolute value of the maximum double thickening efficiency difference (ΔTE) between the polymers in any two different reference oils in the array.

[0048] "Cold Cranking Simulator (CCS)" is a measure of the cold weather cranking characteristics of a crankcase lubricant and is conventionally determined using the techniques described in ASTM D5293-92. Using the "Scanning Brookfield" the apparent viscosity of engine oil at low temperatures can be measured. It is approximately 0.2s -1 A shear rate of 0.01% is produced at a shear stress of less than about 100 Pa. The apparent viscosity is measured continuously as the sample is cooled at a rate of about 1°C / hour over the range of about -5°C to about -40°C, or to a temperature at which the viscosity exceeds 40,000 mPa·s (cPs). The test procedure is specified in ASTM D5133-01. Measurements resulting from the test method are reported as viscosity in mPa·s or equivalent cPs, the maximum viscosity increase (gelation index), and the temperature at which the gelation index occurs. A Mini Rotary Viscometer (MRV)-TP-1 is used to measure the yield stress and viscosity of engine oils after cooling at a controlled rate over a period of about 45 hours to a final test temperature of about -15°C to about -40°C. The temperature cycle is specified in SAE Paper No. 850443 by KOHenderson et al., and first measures the yield stress (YS) at the test temperature, then cools for about 0.4 s. -1 ~ approx. 15 seconds -1 The apparent viscosity is measured at a shear stress of approximately 525 Pa over a shear rate of 100 Hz. Apparent viscosity is reported in mPa·s or the equivalent cPs.

[0049] "Pour point" is a measure of the ability of an oil composition or oil component to flow as the temperature is reduced. Performance is reported in °C and measured using the test procedure described in ASTM D97-02. After preheating, the sample is cooled at a specified rate and the flow characteristics are examined at intervals of approximately 3 °C. The lowest temperature at which the specimen is observed to move is reported as the pour point. MRV-TP-1, CCS, and pour point each typically indicate the low temperature viscosity characteristics of an oil composition. The "Beaker Flow-Through" test measures the bulk flow of a composition at a given temperature from a 600 mL beaker oriented at an angle of about 96° to a horizontal platform surface. The Beaker Flow-Through test can be performed on samples held at a given temperature for as little as about 24 hours (week 0) or for extended periods, such as up to 12 weeks or longer. The Beaker Flow-Through value is the fraction of the sample that flows out of the beaker in about 2 minutes, expressed as a percentage (= [sample before test + beaker mass] - [sample immediately after test + beaker mass]). The Beaker Flow test is reported herein for a week 0 sample held at about 80°C (± 1°C), and any portion of the sample present on the exterior wall of the beaker in an upright position (laying horizontally on a horizontal platform surface) after testing is wiped off with a dry tissue for safety.

[0050] Another measure of the fluidity of a composition includes tan δ, which is the ratio of the loss modulus (G'') to the storage modulus (G') of the composition. Tan δ theoretically encompasses the ratio of the tensile modulus (E'' / E'), and is understood herein as the ratio of the shear modulus (G'' / G'), which better indicates the fluid viscous state in which the triblock copolymer sample exists. The tan δ values ​​expressed herein were measured on an ARES™ G2 rheometer, commercially available from TA Instruments, New Castle, Delaware, with its native software package (TRIOS™), using about 25 mm parallel plates with a gap of either about 0.5 mm or about 1 mm. The samples were cycled twice from about 25°C to about 200°C and back at a ramp rate of about 5.0°C / min. The tan δ data reflected measurements taken at a temperature of about 25°C at the beginning of the first ramp with an angular frequency of about 10 rad / sec and a maximum oscillatory strain of about 10% (the value at the beginning of the second ramp was inspected and was within measurement error).

[0051] The "crystallinity" of ethylene-alpha-olefin copolymers can be measured using X-ray techniques known in the art as well as by using differential scanning calorimetry (DSC) testing. Using DSC, crystallinity can be measured as follows: The polymer sample is slowly cooled at room temperature (e.g., about 20-25°C) for at least 24 hours before measurement. The sample is then first cooled from room temperature to about -100°C and then heated at 10°C / min to about 150°C. Crystallinity is calculated as follows: Crystallinity%=(ΣΔH)*x m エチレン *14÷4110*100% where ΣΔH (J / g) is the total heat absorbed by the polymer above its glass transition temperature, and x m エチレン is the mole fraction of ethylene in the polymer, calculated, for example, from proton NMR data, 14 (g / mol) is the approximate molar mass of a methylene unit, and 4110 (J / mol) is the approximate heat of fusion of a polyethylene single crystal at equilibrium. The "coil collapse temperature (CCT)" can be measured by plotting relative viscosity versus temperature, where "relative viscosity" is the ratio of the kinematic viscosity of about 1 wt. % polymer in a solvent at about 100° C. to the kinematic viscosity of the solvent at about 100° C. (KV100). The CCT is the temperature at which the relative viscosity is highest. "Viscosity Index" measures the sensitivity of a lubricating oil composition (or base stock) to changes in temperature. Viscosity Index can be calculated using the following formula:

number

[0052] Examples 1 to 6 Examples 1-4 describe linear triblock copolymers of type D'-PA-D'' according to the present disclosure. In these examples, the higher molecular weight diene block is D' and the lower molecular weight diene block is D''. The polyarene block in these examples is a polystyrene block. Examples 1A, 2A, 3, and 4 include linear triblock copolymers in concentrate form having "active ingredient" (AI) concentrations of about 6%, about 7.5%, about 12%, and about 6% by weight, respectively, when substantially dissolved or suspended in a "standard" Group III diluent oil (Yubase4) having a KV100 of about 4 cSt. Examples 1B and 2B include the same linear triblock copolymer in concentrate form having an AI concentration of about 6% by weight, each substantially dissolved or suspended in a "non-standard" Group III diluent oil (GTL4) (synthetically produced using a gas-to-liquid process) having a KV100 of about 4 cSt. The KV100 of each concentrate sample, as well as the molecular weight of the block copolymer segment of the linear triblock copolymer, the base stock diluent, and the active ingredient concentration are depicted in Table 1 below. Comparative Examples 5 and 6 are also depicted in Table 1 below, which shows linear diblock copolymers of type D'-PA, in which the diene block D' has a molecular weight of about 65 kilodaltons and about 55 kilodaltons, respectively, and the polyarene (polystyrene) block PA has a molecular weight of about 35 kilodaltons and about 23 kilodaltons, respectively. The base stock diluent is a "standard" Group III base stock (Yubase4) in Comparative Example 5, and a "non-standard" Group III base stock (GTL4) in Comparative Example 6. As can be seen from Table 1 below, each diblock copolymer gelled in its diluent oil, instead of showing a measurable KV100, even at an active ingredient concentration as low as about 5 wt.%. [Table 2]

[0053] Examples 7 to 28 Examples 7-26 describe linear triblock copolymers of type D'-PA-D'' according to the present disclosure. In these examples, the higher molecular weight diene block is D' and the lower molecular weight diene block is D''. The polyarene blocks in these examples are polystyrene blocks. In these examples, the "active ingredient" (AI) concentration of the linear triblock copolymer in concentrate form may vary from about 6% to about 8%, to about 10%, to about 12%, to about 14% by weight when substantially dissolved or suspended in one or more of the following diluent oils: a Group II base stock having a KV100 of about 4 cSt (Star4); a "standard" Group III base stock having a KV100 of about 4 cSt (Yubase4); a "non-standard" Group III base stock (synthetically produced using a gas-to-liquid process) having a KV100 of about 4 cSt (GTL4); and a Group IV (polyalphaolefin) base stock having a KV100 of about 4 cSt (PAO4). The KV100 of each concentrate sample, as well as the molecular weight of the block copolymer segment of the linear triblock copolymer, the base stock diluent, and the active ingredient concentration, are depicted in Table 2 below. If the linear triblock copolymer showed gelation during the process of dissolving or suspending in the diluent oil, the KV100 in Table 2 is indicated as "gel". Also shown in Table 2 below are Comparative Examples 27 and 28, which show linear diblock copolymers in concentrate form of type D'-PA, in which the diene block D' has a molecular weight of about 57 kilodaltons and about 72 kilodaltons, respectively, and the polyarene (polystyrene) block PA has a molecular weight of about 21 kilodaltons and about 28 kilodaltons, respectively. As can be seen from Table 2 below, each diblock copolymer gelled in the diluent oil, instead of showing a measurable KV100, even at an active ingredient concentration as low as about 6% by weight.

[0054] In general, but not in all applications, it is believed that lower KV100 values ​​at relatively higher AI concentrations are desirable. Additionally or alternatively, it is believed that the ability of the linear triblock copolymer concentrate sample (example) to exhibit a KV100 of about 3000 cSt or less, or about 2000 cSt or less (and also optionally at least 100 cSt) at as high an AI concentration as possible is desirable. Furthermore, it may be desirable to have a linear triblock copolymer concentrate that exhibits a beaker effluent (week 0) value of at least 87% (or at least 90%, and optionally up to 99%) in addition or alternatively. Furthermore, it may be desirable to have a linear triblock copolymer concentrate that exhibits a tan δ value (measured at about 25° C.) of at least 1.8 (and also optionally up to 30). [Table 3] TIFF0007661034000007.tif250133 TIFF0007661034000008.tif248130 TIFF0007661034000009.tif250138 TIFF0007661034000010.tif250135 TIFF0007661034000011.tif113165

[0055] Table 3 below shows the thickening efficiency (TE) in the four listed diluent oils and the thickening efficiency range (TE range; maximum thickening efficiency of the four diluent oils minus minimum thickening efficiency of the four diluent oils) for each of the linear triblock copolymers of Examples 2-4 and 7-26. Also shown in Table 3 below is the viscosity index (VI) of each linear block copolymer in a "standard" Group III basestock (Yubase4) and Group II basestock (Star4).

[0056] Generally, but not in all applications, moderate or higher individual thickening efficiencies, lower TE ranges, and high or very high viscosity indexes may be considered desirable. In particular, linear triblock copolymers having a TE range of up to 0.5 or up to 0.4, and / or an average thickening efficiency of at least 1.7 or at least 1.8 in Group III diluent oils may be considered desirable. [Table 4]

[0057] The disclosures of all patents, articles, and other documents described herein are incorporated herein by reference in their entirety. Descriptions of compositions comprising, consisting of, or consisting essentially of a number of specified components as presented in this specification and the appended claims should be construed to encompass compositions made by mixing the specified components. The principles, preferred embodiments, and modes of operation of the present invention have been described in the above specification. Applicants' submissions of their invention are not to be construed as limited to the specific embodiments disclosed, as the embodiments of the present disclosure are considered to be illustrative and not limiting. Those skilled in the art can make modifications without departing from the spirit of the invention.

Claims

1. 60% to 95% by weight of diluent oil; and From 5% to 40% by weight of a compound of the formula: D'-PA-D'' A viscosity modifier (VM) concentrate comprising a linear triblock copolymer characterized by: wherein D' represents a diene-derived block, PA represents a monoalkenyl arene-derived block, and D'' represents a diene-derived block, and said linear triblock copolymer is present in an amount effective to adjust the lubricating kinematic viscosity (KV100) of said concentrate at approximately 100°C; The diluent oil has a KV100 of 2 cSt to 40 cSt and the concentrate has a KV100 of 2000 cSt or less and has an 80° C. beaker outflow of at least 87% and / or a tan delta of at least 1.8, where the beaker outflow is the bulk flow of the composition from a 600 mL beaker oriented at an angle of 96° relative to a horizontal platform surface at 80° C. (±1° C.) over a 24 hour period, and tan delta is the ratio of the loss modulus (G″) to the storage modulus (G′) of the composition (G″ / G′).

2. 2. The concentrate of claim 1, wherein the D' and D'' dienes each individually comprise butadiene, isoprene, and mixtures thereof, but are not identical to one another, and the D' and D'' blocks are substantially hydrogenated after polymerization.

3. The D' and D'' dienes each individually represent (i) not more than 3% by weight of butadiene; (ii) at least 97% by weight isoprene; (iii) Both (i) and (ii) 2. The concentrate of claim 1 comprising:

4. 2. The concentrate of claim 1, wherein D' has a number average molecular weight of from 62,000 to 150,000 daltons, PA has a number average molecular weight of from 15,000 to 50,000 daltons, and D'' has a number average molecular weight of from 5,000 to 80,000 daltons.

5. (i) D' has a number average molecular weight of from 63,000 to 95,000 daltons; (ii) the PA has a number average molecular weight of from 20,000 Daltons to 36,000 Daltons; or (iii) both (i) and (ii); The concentrate of claim 4.

6. 5. The concentrate of claim 4, wherein the ratio of the PA number average molecular weight to the sum of the D'+D'' number average molecular weights is from 0.25 to 0.

50.

7. 5. The concentrate of claim 4, wherein the ratio of the number average molecular weight of D' to the number average molecular weight of D'' is from 1.01:1 to 1.25:1, or from 6.00:1 to 20.0:

1.

8. 10. The concentrate of claim 1, wherein the concentrate comprises from 6.0% to 13% by weight of the linear triblock copolymer.

9. 10. The concentrate of claim 1, wherein the diluent oil comprises a Group II base stock, a Group III base stock, and / or a Group IV base stock.

10. 2. The concentrate of claim 1, wherein the KV100 of the concentrate is from 100 cSt to 1600 cSt.

11. 2. The concentrate of claim 1, wherein the KV100 of the concentrate is 100 cSt or lower.

12. 10. The concentrate of claim 1, further comprising one or more of an ashless dispersant, a surfactant, an antiwear agent, an antioxidant, a corrosion inhibitor, a friction modifier, an antifoam agent, a seal swell control agent, or combinations thereof.

13. 60% to 90% by weight of diluent oil; and From 10% to 40% by weight of a compound of the formula: D'-PA-D'' 1. A VM concentrate comprising a linear triblock copolymer characterized by: wherein D' represents a diene-derived block, PA represents a monoalkenyl arene-derived block, and D'' represents a diene-derived block, and said linear triblock copolymer is present in an amount effective to adjust the lubricating kinematic viscosity (KV100) of said concentrate at approximately 100°C; A concentrate, wherein the KV100 of the diluent oil is from 2 cSt to 40 cSt and the KV100 of the concentrate is 3000 cSt or lower.

14. 14. The concentrate of claim 13, wherein the D' and D'' dienes each individually comprise butadiene, isoprene, and mixtures thereof, but are not identical to one another, and the D' and D'' blocks are substantially hydrogenated after polymerization.

15. The D' and D'' dienes each individually represent (i) not more than 3% by weight of butadiene; (ii) at least 97% by weight isoprene; (iii) Both (i) and (ii) 15. The concentrate of claim 14, comprising:

16. 14. The concentrate of claim 13, wherein D' has a number average molecular weight of from 20,000 to 60,000 daltons, PA has a number average molecular weight of from 10,000 to 40,000 daltons, and D'' has a number average molecular weight of from 5,000 to 40,000 daltons.

17. (i) D' has a number average molecular weight of from 25,000 to 50,000 daltons; (ii) the PA has a number average molecular weight of from 15,000 Daltons to 35,000 Daltons; and (iii) D″ has a number average molecular weight of from 7,000 to 20,000 Daltons. The concentrate of claim 16, wherein the concentrate satisfies one or more of the following:

18. 17. The concentrate of claim 16, wherein the ratio of the PA number average molecular weight to the sum of the D'+D'' number average molecular weights is from 0.25 to 0.

50.

19. 17. The concentrate of claim 16, wherein the ratio of the number average molecular weight of D' to the number average molecular weight of D'' is from 1.4:1 to 3.0:1, or from 6.00:1 to 20.0:

1.

20. 14. The concentrate of claim 13, wherein the diluent oil comprises a Group II base stock, a Group III base stock, and / or a Group IV base stock.

21. 14. The concentrate of claim 13, wherein the KV100 of the concentrate is from 1000 cSt to 2000 cSt.

22. 14. The concentrate of claim 13, having an 80°C beaker overflow of at least 85% and / or a tan δ of at least 1.5, where the beaker overflow is the bulk flow of the composition from a 600 mL beaker oriented at an angle of 96° relative to a horizontal platform surface at 80°C (±1°C) over a 24 hour period, and tan δ is the ratio of the loss modulus (G'') to the storage modulus (G') of the composition (G'' / G').

23. 14. The concentrate of claim 13, further comprising one or more of an ashless dispersant, a surfactant, an antiwear agent, an antioxidant, a corrosion inhibitor, a friction modifier, an antifoam agent, a seal swell control agent, or combinations thereof.

24. 60% to 95% by weight of diluent oil; and From 5% to 40% by weight of a compound of the formula: D'-PA-D'' 1. A VM concentrate comprising a linear triblock copolymer characterized by: wherein D' represents a diene-derived block, PA represents a monoalkenyl arene-derived block, and D'' represents a diene-derived block, said linear triblock copolymer exhibiting a thickening efficiency range of up to 0.5 and present in an amount effective to adjust the lubricating kinematic viscosity (KV100) of said concentrate at approximately 100°C; The diluent oil has a KV100 of 2 cSt to 40 cSt, the concentrate has a KV100 of 2000 cSt or less, and the thickening efficiency range is the difference between the maximum thickening efficiency of a linear triblock copolymer in a diluent oil selected from any one of Yubase 4, GTL 4, PAO 4, and Star 4, and the minimum thickening efficiency of the linear triblock copolymer in a diluent oil selected from any one of Yubase 4, GTL 4, PAO 4, and Star 4.

25. 25. The concentrate of claim 24, wherein the effective amount of the linear triblock copolymer is an amount wherein the concentrate comprises from 6.0% to 14% by weight of the linear triblock copolymer.

26. 25. The concentrate of claim 24, wherein the D' and D'' dienes each individually comprise butadiene, isoprene, and mixtures thereof, but are not identical to one another, and the D' and D'' blocks are substantially hydrogenated after polymerization.

27. 27. The concentrate of claim 26, wherein D' has a number average molecular weight of from 30,000 to 95,000 Daltons, PA has a number average molecular weight of from 20,000 to 35,000 Daltons, and D'' has a number average molecular weight of from 1,800 to 60,000 Daltons, and the ratio of the number average molecular weight of D' to the number average molecular weight of D'' is from 1.0:1 to 30:

1.

28. 25. The concentrate of claim 24, wherein the linear triblock copolymer exhibits an average thickening efficiency of at least 1.8 in Group III diluent oil.

29. 25. The concentrate of claim 24, wherein the diluent oil comprises a Group II base stock, a Group III base stock, and / or a Group IV base stock.

30. 30. The concentrate of claim 29, wherein the diluent oil comprises a Group II base stock and / or a Group III base stock.

31. 25. The concentrate of claim 24, wherein the KV100 of the concentrate is from 100 cSt to 1600 cSt.

32. 25. The concentrate of claim 24, having an 80°C beaker overflow of at least 87% and / or a tan δ of at least 1.8, where the beaker overflow is the bulk flow of the composition from a 600 mL beaker oriented at an angle of 96° relative to a horizontal platform surface at 80°C (±1°C) over a 24 hour period, and tan δ is the ratio of the loss modulus (G'') to the storage modulus (G') of the composition (G'' / G').

33. 25. The concentrate of claim 24, further comprising one or more of an ashless dispersant, a surfactant, an antiwear agent, an antioxidant, a corrosion inhibitor, a friction modifier, an antifoam agent, a seal swell control agent, or combinations thereof.

34. 2. A method for adjusting the kinematic viscosity at approximately 100° C. (KV100) of a VM concentrate according to claim 1, comprising adding to the concentrate a compound having the formula: D'-PA-D'' and adding an effective amount of said linear triblock copolymer characterized by D' represents a block derived from a diene, PA represents a block derived from a monoalkenyl arene, and D'' represents a block derived from a diene, The method of claim 1, wherein the effective amount of the linear triblock copolymer comprises at least 6.0 wt.% of the concentrate, and the concentrate has a KV100 of 2000 cSt or less.

35. 14. A method for adjusting the kinematic viscosity at approximately 100° C. (KV100) of the concentrate of claim 13, comprising adding to the concentrate a compound having the formula: D'-PA-D'' and adding an effective amount of said linear triblock copolymer characterized by D' represents a block derived from a diene, PA represents a block derived from a monoalkenyl arene, and D'' represents a block derived from a diene, The method of claim 1, wherein the effective amount of the linear triblock copolymer comprises at least 9.5% by weight of the concentrate, and the concentrate has a KV100 of 3000 cSt or less.

36. 25. A method for adjusting the kinematic viscosity at approximately 100° C. (KV100) of a VM concentrate according to claim 24, comprising adding to the concentrate a compound having the formula: D'-PA-D'' and adding an effective amount of said linear triblock copolymer characterized by During the ceremony, D' represents a block derived from a diene; PA represents a block derived from a monoalkenyl arene; D″ represents a block derived from a diene, The linear triblock copolymer exhibits a thickening efficiency range of up to 0.5; The method, wherein the concentrate comprising the effective amount of the linear triblock copolymer has a KV100 of 2000 cSt or less.

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