JPH03212496A - Lubricating oil additive package containing viscosity index improver - Google Patents

Abstract

PURPOSE: To provide a gel-free liquid crankcase lubricating oil additive concentrate having a storage stability which comprises a dilute oil, an ashless dispersant and an effective amount of a viscosity index inprover.

CONSTITUTION: This concentrate comprises (A) a dilute oil comprising a mineral oil and/or a synthetic oil, etc., (B) an ashless dispersant comprising, preferably, polyethylene polyamine tetrathylenepentamine, and (C) an effective amount of a viscosity index inprover comprising, preferably, succinic acid imide substituted by a polyisobutenyl group having a number average molecular weight of form 800 to 5,000, an olefin hydrocarbon polymer functionalized with a vinyl monomer such as N-vinyl pyrrolidone, etc.

COPYRIGHT: (C)1991,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to concentrates for formulating lubricating compositions, and more particularly to concentrates containing viscosity index improvers.

In summary of the present invention, a storage stable, non-gelling liquid crankcase lubricant additive concentrate is prepared containing an ashless dispersant, a viscosity index improver, and a diluent oil.

Lubricant additive concentrates, such as those blended with mineral or synthetic base oils to make motor oils, typically contain dispersants, detergents, corrosion and oxidation inhibitors, and wear along with certain process oils. Contains various additives such as reducing agents. Viscosity index improvers are also added to motor oils to reduce the viscosity changes that would normally accompany changes in temperature, making the oil more resistant to thickening at lower temperatures and more resistant to thinning at higher temperatures. For example, US Patent 4
, 519,929, which also act as dispersants.

In practice, viscosity index improvers, including those that also act as dispersants, cause irreversible gelation of the concentrate upon addition to the concentrate. For this reason, viscosity index improvers are generally packaged separately and added to the base oil separately from the lubricant additive concentrate.

It has now been discovered that viscosity index improvers can be included with other lubricant additives in lubricant additive concentrates without gelling. In particular, the viscosity index improver is preferably applied to a concentrate containing an ashless dispersant, diluent oil, and optionally other additives to provide a diluent oil to active ingredient ratio of at least about 0.6:1. can be added in an amount to give a ratio in the range of 0.7:l-3,3:l. Therefore,
The present invention provides a storage stable crankcase lubricant additive concentrate containing an ashless dispersant and a diluent oil along with an effective amount of a viscosity index improver.

Within certain ranges of ratios of the diluent oil-sealing active additive components, the diluent oil, ashless dispersant, and optionally, such as detergents, antioxidants, anti-wear compositions, anti-corrosion compositions, etc. It has been discovered that viscosity index improvers can be included in concentrates containing other additives. The resulting concentrate is a storage-stable liquid that does not gel or exhibit significant amounts of sediment upon standing. It can be added to mineral or synthetic base oils to form effective rank case lubricating compositions.

The term viscosity index improver, as used herein, refers to an elastomeric polymer composition that imparts improved flow properties to the oil and reduces the tendency of the oil to change viscosity in response to changes in temperature. . Viscosity index improvers or viscosity modifiers impart high and low temperature operability to lubricating oils, allowing them to remain relatively tacky at high temperatures and relatively fluid at low temperatures. Viscosity modifiers are generally high molecular weight hydrocarbon polymers and polyesters. The viscosity modifier can also be derived to include other properties or functions, such as dispersing additions. These oil-soluble viscosity modifying polymers generally have a viscosity of 10"-10', preferably 10'-10", e.g. 20,000-250,000, as measured by gel permeation chromatography or osmometer.
It has a number average molecular weight of .

Examples of hydrocarbon polymers suitable for the preparation of viscosity index improvers include monomers of C, -C3, such as C2-C, olefins, including two or more Al7 aolefins and internal olefins Homopolymers and copolymers of linear or branched, aliphatic, aromatic,
Can be alkyl-aromatic or cycloaliphatic.

Particularly preferred are copolymers of ethylene and propylene. For example, polyisobutylenes, homopolymers and copolymers of C6 and higher alpha olefins, atactic polypropylene, hydrogenated polymers, and copolymers and terpolymers of styrene with, for example, isoprene and/or butadiene. Other polymers can also be used, such as polymers, as well as their hydrogenated derivatives. The polymer can be reduced in molecular weight, for example by mastication, extrusion, oxidation or thermal degradation, or it can be oxidized and still contain oxygen.

Also included are derived polymers, such as post-grafted internal polymers with active monomers such as maleic anhydride, which can be further reacted with alcohols, or amines, such as alkylene polyamines or alkylene hydroxyamines. For example, U.S. Patent No. 4,
089,794.4°160.739.4,137,1
See 85.

Other derivatized polymers useful in the compositions of the invention include:
Copolymers of ethylene and propylene reacted with or grafted with nitrogen compounds are included, e.g., U.S. Patent No. 4.068.056.4,
068,058.4,146.489 and 4,149
, 984.

A preferred hydrocarbon polymer is an ethylene copolymer containing 15-90% by weight ethylene copolymerized with 10-85% by weight of at least one C3CHI alpha olefin. Most preferably, the hydrocarbon copolymer is 30-80% by weight ethylene copolymerized with 20-70% by weight of at least one 03-C1, alpha olefin. Particularly preferred hydrocarbon polymers are those of ethylene and C,-C, alpha olefins. Among the particularly preferred hydrocarbon polymers, those of ethylene and propylene are most preferred. Although not required, such copolymers preferably have a crystallinity of 25% by weight or less as determined by X-ray and differential scanning calorimetry.

Other suitable to be used in place of propylene to produce the above copolymers or in combination with ethylene and propylene to produce terpolymers, quaternary copolymers, etc. Alpha olefins include ■-butene, l-pentene, ■-hexene, l-heptene, l-octene, 1-nonene, 1-decene, etc., and branched alpha olefins, such as 4-methyl- 1-pentene, 4-methyl-■-hexene, 5-
Also useful are methylhebutene-1, and mixtures thereof.

It is also possible to use terpolymers, quaternary copolymers, etc. of ethylene, C,2, alpha olefins, and nonconjugated diolefins or mixtures of these diolefins. The amount of non-conjugated diolefin is generally 0.520 mol%, preferably 1-7 mol%, based on the total amount of ethylene and alpha olefin present.
The most preferred range is 1.5-5.5 mole %.

Polyester viscosity index (V, 1.) modifiers generally include, for example, methacrylic and acrylic acids, maleic acid,
Ethylene-based C, such as maleic anhydride, fumaric acid, -
c, a polymer of esters of mono- and/or dicarboxylic acids. Examples of unsaturated esters that can be used in embodiments of the invention include aliphatic saturated monoalcohols having at least 1 to about 25 carbon atoms and preferably 12 to 20 carbon atoms, such as decyl acrylate. , lauryl acrylate, stearyl acrylate, eicosanyl acrylate, docosanyl acrylate, decyl methacrylate, cyamyl fumarate, lauryl methacrylate, cetyl methacrylate, stearyl methacrylate, and mixtures thereof. Other esters include c2
Included are vinyl alcohol esters of C22 fatty acids or monocarboxylic acids, such as vinyl acetate, vinyl laurate, vinyl balmitate, vinyl stearate, vinyl oleate, and mixtures thereof. It is also possible to use copolymers of vinyl alcohol esters and unsaturated acid esters, such as copolymers of vinyl acetate and dialkyl heptamarate.

The esters may be further combined with other unsaturated monomers such as olefins, such as 0.2-5 moles of C2C20 aliphatic or aromatic olefins per mole of unsaturated ester or per mole of unsaturated acid or anhydride. Examples include copolymers of styrene and maleic anhydride esterified with alcohols and amines. See US Patent No. 3,702,300. In such copolymerized esters,
0.2-5 moles of C2- per mole of unsaturated ester
C, o aliphatic or aromatic olefins are used. Instead of an unsaturated ester, the corresponding unsaturated acid or anhydride can be first treated with an olefin and the resulting copolymer esterified with an alcohol or reacted with an amine.

The term "dispersant viscosity index improver" as used herein refers to crankcase lubricants used in spark-ignition and compression-ignition engines because they contain functional groups that not only enhance the viscosity properties of the oil. The present invention describes a polymeric composition that imparts improved dispersibility to agents to aid in the dispersion of slag that forms in lubricating oils during engine operation. It may be grafted with or copolymerized with polymerizable unsaturated nitrogen-containing monomers to impart dispersant properties to the V, I modifier. Examples of suitable unsaturated nitrogen-containing monomers Examples include those having 4 to 20 carbon atoms, such as amine-substituted olefins, such as f:t'p-(heterdiethylamineethyl)styrene, and basic nitrogen having a polymerizable ethylenically unsaturated substituent. -containing heterocycles, such as vinylpyridines and vinylalkylpyridines, such as 2-beer-pyridine, 4-vinyl-pyridine, 3-vinyl-pyridine, 3-methyl-5-vinyl-pyridine, 4-methyl-2- Vinyl-pyridine, 4-ethyl-2-vinyl-pyridine and 2-butyl-1-vinyl-pyridine, etc. are included. N-vinyl lactams, such as N-vinylpyrrolidones or N-vinylpiperidones, are also dispersants. Suitable as a functional group for producing viscosity index improvers.

Examples of dispersant viscosity index improver (D■) compositions include reacting or grafting with vinyl monomers such as maleic anhydride, 2-vinylpyridine, acrylonitrile, N-vinylpyrrolidone or N-allylamide. Copolymers based on alkyl methacrylates such as those containing N-vinylpyrrolidone and functionalized copolymers based on methyl methacrylate, such as those containing N-vinylpyrrolidone, are and high molecular weight olefin polymers, particularly ethylene-propylene based copolymers. D. Other examples of compositions include copolymers of olefins and the above-mentioned vinyl monomers.

Another example includes high molecular weight olefin polymers (to produce functionalized polyolefin elastomers) and oxidized and then reacted with a functionalizing component such as an amine or an amine and formaldehyde combination. Includes high molecular weight olefin polymers which produce Manitzchi condensate products. Several such viscosity index improvers and methods for their preparation are described, for example, in US Pat. Nos. 4,411,804 and 4,519,929.

Ashless dispersions suitable for use in lubricating oils are known in abutment technology. Examples of such dispersions include polyolefin-substituted succinimides and/or succinimides of polyethylene polyamines such as diethylene triamine and tetrahydrofuran ethylene pentamine. Another example includes polyolefin-substituted succinimides of amido-amines.

The polyolefin succinic acid amide preferably has a molecular weight of 800-500.
It is a polyisobutyne group with a number average molecular weight of 0. Such ashless dispersants are described in U.S. Pat.
,219,666.4,234°435, and 4,8
57.217.

Other useful types of ashless dispersants are polyolefin succinates of 140 carbon hepano and polyhydroxy alcohols. Such dispersants are described in U.S. Pat. No. 3,381.022 and U.S. Pat. No. 3,522.179.
It is written inside.

Mixed ester-amides of polyolefin-substituted succinic acids made with alkanols, amines and/or aminoalkanols are also a useful class of ashless dispersants.

Ashless dispersants of the succinic acid amide, imide and/or ester type can be post-treated, for example boronated by reaction with a boron compound such as boric acid, or maleated by reaction with maleic anhydride. Furthermore, succinic acid amides, imides and/or esters can also be hydroxy-alkylated, for example by reaction with alkylene oxides such as ethylene oxide or propylene oxide.

Other useful ashless dispersants include neutralized reaction products of phosphorous sulfide and polyalkenes as well as N-allylamide-functionalized elastomeric copolymers, such as dimethylformamide-functionalized EPDM. be done. See, eg, US Pat. No. 4,519.929.

Still other useful ashless dispersants are Mannich condensation products of polyolefin-substituted phenols, formaldehyde, and polyethylene polyamines. Preferably, the polyolefin phenol has 8 polyisobutylene groups.
It is a polyisobutylene-substituted phenol with a molecular weight of 00-5000. Preferably the polyethylene polyamine is tetraethylenepentamine. Such Manitzhi ashless dispersants are described in U.S. Pat. No. 3,368,972.
．． 3,413,347.3,442,808.3°44
8.047.3,539,633.3,591°598
．． 3,600,372.3,634,515.3.69
7,574.3,703,536.3,704.308
．． 3,725,480.3,726,882.3,73
6,357.3,751,365.3°756.953
．． 3,792,202.3,798°165.3,79
8,247 and 3,803.039.

Mixtures of any of the useful ashless dispersants described above, such as mixtures of Mannich ashless dispersants and succinimide dispersants or mixtures of succinimides and succinic esters, are also suitable for use in the present invention. Such mixtures can also be worked up, for example by boration or maleation.

The concentrates of the present invention can contain optional additives. See, eg, US Pat. No. 4,857,217.

For example, detergent additives are one such optional additive. Such additives used in the compositions of the invention include alkali and alkaline earth metal petroleum sulfonates, alkali and alkaline earth metal alkyl or alkaryl sulfonates, alkyl heptaenates and metal carboxylates. is included. Examples of these are calcium petroleum sulfonates, magnesium petroleum sulfonates, barium alkaryl sulfonates, calcium alkaryl sulfonates, magnesium alkaryl sulfonates and calcium and magnesium alkyl sulfonates. Neutral and overbased sulfonates or heptenonates having a base number of up to about 600 which provide acid-neutralizing properties can be advantageously used and are commercially available. These detergent additives are generally 0.05-1.5% by weight
and more preferably in an amount to provide 0.1-1.0% by weight of alkaline earth metal. The lubricating oil compositions of the present invention preferably contain calcium petroleum sulfonates or alkaryl (eg alkylbenzene) sulfonates as detergent additives.

Other optional additives for compositions of the invention include ashless antioxidants, such as alkylphenols, alkyldiphenylamines, and sulfur-bridged amine phenols; antiwear/corrosion inhibitors, such as dialkyl Selenides, metal dithiocarbamates, sulfuric acid-treated terpenes and zinc dihydrocarbyl dithiophosphate (ZDD)
P); Friction reducers and HP additives, such as N-alkylglycine-amides, chlorinated paraffins, sulfuric acid-treated olefins, sulfuric acid-treated oils, sulfuric acid-treated hydroxy-substituted fatty amides , and jointly sulfated fatty acid amides and esters; antifoaming agents,
Included are, for example, acrylate copolymers and silicones; and surfactants such as ethoxylated alkylphenols and poly(alkylene oxides).

The components of the present invention can be used for at least 300 ms at 70° C. in dilute oil, such as mineral oil, synthetic oil or mixtures thereof.
They are combined in effective weight proportions to provide a liquid concentrate that is a storage-stable liquid composition that does not form a gel or significant amount of precipitate upon standing for days. Diluent oils useful for producing concentrates include mineral oils and can be process oils, solvent refined oils, and hydro-processed oils. Examples include process oil #5 and 80 neutral oil.

Diluent oil is typically added to lubricant additive concentrates during their manufacture and/or after manufacture for ease of handling purposes, and the total amount of oil required in providing the stable compositions of the present invention. This oil can be included in addition to all other oils in the calculation of quantities. Therefore, all active ingredient percentages shown herein are on an "active ingredient" basis, ie, do not include additional oils.

To provide a concentrate, for a typical dispersant-inhibitor (DI) without a viscosity index improver, the ratio of the amount of oil to the active ingredients based on the total weight of the concentrate is typically 0.4
:l-0,56: It is l.

To provide a concentrate of the present invention containing a viscosity index improver, the total amount (the sum of all oils used in the concentrate) versus the total active ingredient or additive ingredient (the active ingredient is the oil ) is at least about 0.6:1, preferably at least about 0.7:11, most preferably 0.7:1.
1-3.3: L.

The compositions may also contain effective amounts of one or more of the other additives described above. For example, about 10% by weight of the composition of the invention.
up to (preferably 0.05-5 wt.%) ashless antioxidant, up to about 15 wt.% (preferably 5-10 wt.%)
Detergents; anti-wear/corrosion inhibitors up to about 10% (preferably 0.05-5% by weight); friction reducing agents up to about 10% (preferably 0.05-5% by weight); agent, up to about 2% (preferably 0.1-1%) of a surfactant and up to about 1% (preferably 0.01-0.1%) by weight of an antifoam agent. I can do it. The present invention relates to the presence of certain of these other additives as well as other factors to provide a stable concentrate, including the necessary dispersants, dispersant viscosity index improvers, and oil mist. The amounts of the components useful in the composition (which may result in certain changes in the composition) to obtain a stable concentrate containing a selected dispersant viscosity index improver in accordance with the teachings of the present invention. It is within the ability of those skilled in the art to vary the weight percentages of each additive and diluent oil.

The concentrates of the present invention can be manufactured using in-shell compounding equipment and techniques. Add them to the base oil and the required additive level in the finished rank case lubricant, e.g. 10-2.
Blend in an amount that gives a treatment rate of 0%. Suitable base oils include both mineral and synthetic oils and blends thereof, as known in the art.

Mineral oils include those of suitable viscosity refined from crude oils of all origins, including the Gulf Coast, Midwest, Pennsylvania, California, Middle East, North Sea, Alaska, Far East, and the like.

A variety of standard refining operations are useful in processing mineral oils.

Synthetic oils include both hydrocarbon synthetic oils and synthetic esters. Useful synthetic hydrocarbon oils include liquid polymers of alpha olefins of suitable viscosity. Particularly useful are, for example, hydrogenated liquid oligomers of CICI2 alpha olefins, such as alpha decene trimer. Similarly, alkyl-benzenes of suitable viscosity, such as didodecylbenzene, can also be used as synthetic oils.

Useful synthetic esters include esters of both monocarboxylic and polycarboxylic acids with monohydroxyalkanols and polyols. Representative examples include didodane adipate, trimethylolpropane tripelargonate, pentaerythritol tetracaproate, di(2-ethylhexyl) adipate, dilauryl sebacate, and the like. It is also possible to use complex esters prepared from mixtures of mono- and dicarboxylic acids and mono- and polyhydroxyl alkanols.

The invention is further illustrated by, but not intended to be limited to, the following examples, in which parts and percentages are by weight unless otherwise indicated.

Examples 1-9 These examples illustrate storage stable concentrates containing together selected viscosity index improvers in accordance with the teachings of the present invention. The liquid crankcase concentrate formulations identified in Table 1 were prepared by incorporating all additive components into an amount of diluent, followed by incorporating therein an oil solution of the viscosity index improver. . The concentrate thus produced is kept at 70°C to ensure storage stability (70°C
The number of days during which no gel was formed was measured. Visual measurements were performed for the purpose of determining gelation for these examples. The concentrate contains a thick and sometimes sticky substance (usually at the top of the fluid) or a web-like structure dispersed throughout the fluid (usually appearing as a string-like material when poured) If so, such a concentrate is identified as "gelled."

Table 1 Ratio Diluent oil at 70°C Other C non-gelling dispersant (A)
) Morotyo Cuisine and Superintendent 1 14.11 1.92 6
6.29 17.68 2:l 652
14.11 1.92 66.29 17.68
2:1 653 13.56 1.02 6
5.84 19.58 1.9:l 734
13.56 1.02 65.84 19.58
1.9:l 655 12.53 1.7
1 66.79 18.97 2:l 736
12.53 1.71 66.79 1
8.97 2:1 657 12.03
2.26 68.34 17.37 2.2+1
658 12.03 2.26 68.34
17.37 2.2:l 749 11.
86 1.75 64.52 21.87 1
．． 8:l 60A-% by weight, active alkenyl (molecule 1
Approximately 1300) Succinimide ashless dispersant.

B - Activated EDPM olefin copolymer (orthulium 2052) consisting of ethylene, propylene and diene monomers grafted with about 5% N,N-diallylformamide by weight, molecular weight 40,000°C- Weight %, active process oil.

D - % by weight, active additives such as detergents, wear reducers, oxidation and corrosion inhibitors, etc.

Example 1O Following the steps of Examples 1-9, 2.07% by weight of a commercially available pyrrolidone-containing acrylate-type dispersant viscosity index improver (D
VI Improver or D■) (Acryloid 956D■ Rohm and Haas), 68.53% by weight total oil and 12.03% by weight alkenyl (molecular weight, approx. 1300
) A formulation was prepared containing a succinimide ashless dispersant (ratio of total oil to total active ingredients was 2.2). 70
No gel formed after 57 days at °C. 1.7
3% by weight acryloid 956D■, 15.09% by weight
A formulation containing 30% succinimide dispersant and 62.98% by weight diluent oil (ratio of total oil to total active ingredients is 1.7) was also stable for 57 days.

Example 11 A DVI modifier was added to 2.07% by weight of an oxidized and functionalized (Schiff base) olefin polymer type dispersant viscosity index (D
Example 1 except that VT) improver (Amoco 6906D) was substituted and the total oil was adjusted to 68.53% by weight.
A formulation according to 0 was prepared. The concentrate is 5 at 70°C.
Stable after 7 days.

Example 12 2.07% by weight of a succinimide-grafted olefin polymer type DVI improver (Paratone 856)
Example 1 except that D■, Exxon Corporation) and the total oil was adjusted to 68.53% by weight.
A formulation according to O was prepared. The concentrate is 5 at 70°C.
It was stable after 7 days.

Example 13 Example except that the DVI improver was replaced with 2.07% by weight of Manitzchi reaction bioacid DVI improver (Amoco 6565, Amoco Corporation) and the total oil was adjusted to 68.53% by weight. A formulation according to 10 was prepared. The concentrate was stable after 57 days at 70"C!.

Examples 14-21 Table 2 shows that the viscosity index improver (■) was added to the concentrate and
Examples are included that illustrate other additive concentrates of the present invention that do not undergo gelation in the concentrate when kept at 0°C for at least about 30 days. These concentrates were the same as Examples 1-13 except that the ratio of total oil (the sum of all oils used in the concentrate) to total additives (the active ingredient category did not include oil) was changed. Manufactured according to the process used. In the table, the letters a-i represent dispersants and modifiers according to the following scheme: a, alkenyl (molecule 1 about 1300) succinimide ashless dispersant, alkenyl (molecule 1 about 900) succinimide Ashless dispersant C, alkenyl (molecule 1 about 2100) succinimide ashless dispersant d, EPDM grafted with about 5% N,N-dialkylformamide (Orthorum 2052), molecular weight 40.000 e, (d ') and (f) mixture f, non-dispersing agent type, certain olefin copolymer type ■ (orthorum 2052) g, Amoco 656h identified in Example 13, acrylate type non-dispersing agent ■ improvement Acryloid 7°2D (i, t-refin copolymer type) manufactured by Rohm and Haas (Paratone 715, Exon Corporation).

Table 14 a 15 a 16 a 17 a 18 a 19 b 20 c 21 a dl, 3 8 1.4 r2.4 g2.5 h O, 7 d 1.6 d2.6 12.5 Example 22-25 As summarized in Table 3, these examples illustrate the effect of varying the total oil to total active ingredient ratio to obtain a non-gelling concentrate. The letters a, d and g represent dispersants and improvers according to the system shown for Table 2, and concentrates were prepared as in Example 1.

Table 3 22 a d 1.2
gel 23 a d
1.4 Transparent 24 a
g 1.2 gel 25
a g 1.4
The main features and aspects of the transparent invention are as follows.

1. A lubricant additive concentrate consisting of a diluent oil, an ashless dispersant, and an effective amount of a viscosity index improver, having a ratio of total oil to total active ingredients to provide a storage stable liquid.

2. The concentrate of 1 above, wherein the ashless dispersant consists of a polyolefin-substituted succinimide.

3. The concentrate of 2 above, wherein the ashless dispersant consists of a polyisobutenyl-substituted succinimide having polyisobutenyl groups having a number average molecular weight of 800 to 5.000.

4. The concentrate according to any one of 1-3 above, wherein the viscosity index improver is an olefinic hydrocarbon polymer or a polyester viscosity index improver.

5. The concentrate of any of 1-3 above, wherein the viscosity index improver consists of an alkyl methacrylate-based polymer or a succinimide-grafted polyolefin.

6. A dispersant in which the viscosity index improver comprises an olefinic hydrocarbon polymer functionalized with a vinyl monomer selected from the group consisting of N-vinylpyrrolidone, 2-vinylpyridine, acrylonitrile, and N-allylamides. The concentrate according to any one of 1-3 above, which is a viscosity index improver.

7. The concentrate of 1 above, wherein the viscosity index improver is a dispersant viscosity index improver and comprises a functionalized polyolefin elastomer.

8. The concentrate of any of the preceding clauses, wherein the ratio is at least 0.6 to 1.0.

9. The concentrate of 8 above, wherein the ratio is 0.7:1-3.3:l.

A method of producing a storage-stable liquid lubricant additive concentrate comprising an ashless dispersant, an effective amount of a viscosity index improver, and optionally other lubricant additives in a lO6 diluent oil, the method comprising dispersing A method comprising incorporating lubricant additives and other lubricant additives into a diluent oil and incorporating therein an oil solution of a viscosity index improver.

Claims (1)

Claims: 1. A lubricant additive consisting of a diluent oil, an ashless dispersant, and an effective amount of a viscosity index improver, having a ratio of total oil to total active ingredients to provide a storage stable liquid. concentrate. 2. Ashless dispersant and effective amount of viscosity index improver in diluent oil;
and optionally other lubricant additives, the method comprising incorporating a dispersant and other lubricant additives into a diluent oil and adding A method consisting of formulating an oil solution of a viscosity index improver.