EP0794995A1

EP0794995A1 - Polymer blends containing olefin copolymers and star branched polymers

Info

Publication number: EP0794995A1
Application number: EP95943653A
Authority: EP
Inventors: Alfred Karl Jung; Maria Magdalena Kapuscinski; James W. Moore; Robert T. Biggs
Original assignee: Afton Chemical Additives Corp
Current assignee: Afton Chemical Additives Corp
Priority date: 1994-12-02
Filing date: 1995-12-04
Publication date: 1997-09-17
Also published as: AU4507296A; WO1996017041A1

Abstract

This invention relates to novel polymer blends used as additives and which improve the viscosity index of lubricating oils. Specifically, the polymer additive compositions comprise partially crystalline olefin copolymers (OCP) such as EPM (ethylene-propylene cpolymer) or EPDM (ethylene-propylene diene terpolymer) and star styrene isoprene polymers or amorphous OCPs such as EPM or EPDM and star styrene/isoprene based polymers or crystalline and amorphous olefin copolymers with star styrene/isoprene based polymers. The additive compositions disclosed are particularly useful for preparing solid polymers with excellent dimensional stability. These polymer blends when dissolved in mineral oils comprise lubricant additives which improve the viscosity index and low temperature properties of lubricating oil compositions. Blends of crystalline and amorphous EPM or EPDM with attached polar functional groups and star polymers are also useful as additives. These materials have multifunctional performance properties and are referred to as dispersant or dispersant/antioxidant olefin copolymers.

Description

POLYMER BLENDS CONTAINING OLEFIN COPOLYMERS AND STAR BRANCHED POLYMERS

FIELD OF THE INVENTION

This invention relates to additive compositions. Specifically, the present invention relates to additives which are blends of either crystalline olefin copolymers and star branched polymers or amorphous olefin copolymers and star branched polymers or blends of crystalline and amorphous olefin copolymers with star branched polymers.

BACKQRQUNP OF THE INVENTION

Lubricating oil compositions which use ethylene- propylene copolymer (EPM) or ethylene-propylene diene terpolymer (EPDM) as viscosity index improvers are known in the art. It is also known that such polymers can be amorphous or partly crystalline based on their ethylene/propylene content. Typically, random EPMs or EPDMs containing 40-70 mole % ethylene are amorphous, while copolymers or terpolymers containing over 70 mole % ethylene are partly crystalline. The crystallinity increases with the amount of ethylene.

Linear amorphous polymers can flow under ambient conditions while the crystalline materials have excellent dimensional stability. At low temperature, solutions of partially crystalline olefin copolymers (OCPs) behave differently from amorphous OCPs as they can form ordered aggregates which tend to reduce viscosity. Lubricating oils containing neat, partially crystalline OCPs show improvement over conventional amorphous OCPs in low temperature cranking or pumbability performance, but their pour points are not satisfactory. In addition, by contrast to amorphous OCP polymer VI improvers, the VI improvers based on partially crystalline OCPs require elevated temperatures for handling and storage as well as special blending conditions to achieve satisfactory performance.

There are several methods described in the literature which have been used to produce EPM or EPDM polymers with good dimensional stability. Briefly, they are related to the following processes: crosslinking reactions by incorporating the multifunctional monomer (Japanese Patents 82/17736 and 90/49033) or by using free radical initiators (Japanese Patent 80/17122 and Chechslovakian Patent CS 85 561) . grafting reactions of compounds like maleic anhydride, (Japanese Patents 90/13/214, 89/123,773, 85/28329, and 85/4138). blends with such polymers as polypropylene (Polymer 1991 32 (7) 1186; Japanese Patent 86/125983; European Patent Application EP452813 AZ) or various inorganic fillers such as glass fibers,talc, silica, mica, etc. (Japanese Patents 85/61692; 84/68387; 90/49033) . The above methods have not been employed for the manufacture of polymers used in motor oil applications to preclude possible problems related to solubility, shear stability or reactivity with other oil components. Star branched isoprene polymer based VI improvers are also known in the art. These VI improvers exhibit good low temperature properties, thickening power as well as excellent shear stability. They do not however exhibit the dimensional stability shown by crystalline OCPs or even by blends of crystalline and amorphous OCPs and may require special packaging during shipment to prevent the polymer from "cold flowing¹*. The use of neat star branched isoprene based VI improvers can add significantly to the cost of a lubricating oil formulation.

It is an object of the present invention to provide a shear stable polymer composition that has good dimensional stability thereby facilitating shipment of the composition. Another object of the present invention is to provide a lubricating oil composition which has good low temperature properties. It is a further object of the present invention to provide a lubricant oil additive which improves the viscosity index of lubricating oil compositions and which is cost effective .

SUMMARY OF THE INVENTION

This invention relates to compositions comprising blends of at least one olefin copolymer and at least one star polymer. Additionally, the instant invention encompasses lubricating oil compositions comprising a mixture of base oil and the present polymer blends.

Compositions falling within the scope of the present invention can be dimensionally stable, and enhance the low temperature properties of a lubricating oil composition to which they have been added, and improve the viscosity index of lubricating oil.

The present invention comprises lubricating oil composition containing a major portion of a lubricating oil (base oil) and minor amounts of a lubricant additive composition comprising crystalline olefin copolymers and star polymers or amorphous olefin copolymers and star polymers or a mixture of crystalline and amorphous olefin copolymers with star polymers.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to dimensionally stable blends of linear crystalline OCPs with star polymers or dimensionally stable crystalline and amorphous OCPs with star polymers or amorphous OCPs with star polymers which are useful for VI improver applications in lubricant oil compositions. These polymeric blends exhibit the desirable properties of their individual components but reduce or eliminate their undesirable properties. Blends of crystalline OCPs and star polymers as well as blends of crystalline and amorphous OCPs with star polymers exhibit dimensional stability and also provide lubricating oil compositions which have a high degree of shear stability and exhibit enhanced low temperature properties. The blend of amorphous OCPs and star polymers can be used in lubricant oil compositions to provide lubricant oil compositions with desirable properties such as good shear stability and enhanced low temperature property.

The novel polymer blend may comprise an oil- soluble composition comprising a star polymer and an amorphous copolymer (random EPM or EPDM) wherein the copolymer or terpolymer has an ethylene content from 40 to 70 mole %, and a partially crystalline copolymer or terpolymer having an ethylene content from above 70 to 85 mole%. It may also comprise a star polymer and a partially crystalline olefin copolymer or terpolymer having an ethylene content from above 70 to 85% mole and a star polymer.

The amorphous and crystalline copolymer and terpolymers may be prepared using known Ziegler-Natta polymerization methods. Ethylene-propylene copolymers (EPM) and ethylene-propylene-diene terpolymers (EPDM) with and without polar groups attached to the main polymeric chain are preferred for the purpose of this invention. The unsaturated monomers (third monomers) used for the preparation of terpolymers are preferably linear, but may be branched. The amount of the third monomer contained in the terpolymer may range from 0.01 to about 10 weight %.

In another embodiment of this invention polymeric additive compositions also comprise blends analogous to those mentioned hereinabove in which amorphous EPM or EPDM with attached polar functional groups are employed. Examples of EPM and EPDM with attached polar groups include but are not limited to all known dispersant olefin copolymers (DOCP) or dispersant antioxidant olefin copolymers (DAOCP) . DOCP and DAOCP are known to workers in the field as exemplified in De Rosa et al U.S. Patents 5,013,469 and 5,112,508 and Kapuscinski et al. U.S. Patent 5,094,766 herein incorporated by reference. When used in the instant lubricant additive compositions the DAOCP and DOCP polymers may be part of or the only OCP used in the lubricant additive mixture of this invention. Preferably blends of DOCP with other OCP's or blends of DAOCP with other OCP's may be used. Preferred blends are about 10 to 70% amorphous OCPs and about 90 to 30% DOCP or about 90 to 30% DAOCP. Most preferred blends are about 30 to 60% of OCPs and about 70 to 40% DOCP or about 70 to 40% DAOCP.

Star polymers are known and can be prepared by anionic polymerization methods as exemplified by Rhodes et al. U.S. Patent 5,035,820 and Echert, U.S. Patent 4,358,565, which are herein incorporated by reference. These polymers generally produced by the process comprising the following reaction steps:

(a) polymerizing one or more conjugated dienes and, optionally, one or more monoalkenyl arene compounds, in solution, in the presence of an ionic initiator to form a living polymer; and

(b) reacting the living polymer with a polyalkenyl coupling agent to form a star- shaped polymer.

Optionally, the star polymer may be hydrogenated. The living polymers obtained by reaction step (a), which are linear unsaturated living polymers, are prepared from one or more conjugated dienes, e.g., C₄ to C,_j conjugated dienes and, optionally, one or more 1 monoalkenyl arene compounds.

Specific examples of suitable conjugated dienes include butadiene (1,3-butadiene) ; isoprene, 1,3- pentadiene (piperylene) ; 2,3-dimethyl-1,3-butadiene; 3- butyl-1,3-octadiene, 1-phenyl-l,3-butadiene; 1,3- hexadiene; and 4-ethyl-1,3-hexadiene with butadiene and/or isoprene being preferred. Apart from one or more conjugated dienes the living polymers may also be partly derived from one or more monoalkenyl arene compounds. Preferred monoalkenyl arene compounds are the monovinyl aromatic compounds such as styrene, monovinylnapthalene as well as the alkylated derivatives thereof such as o-, m- and p-methylstyrene, alpha-methylstyrene and tertiary- butylstyrene. Styrene is the preferred monoalkenyl arene compound.

The living polymers produced in reaction step (a) are then reacted, in reaction step (b) , with a polyalkenyl compounding agent. Polyalkyl compounding agents capable of forming star-shaped polymers are known. See generally, Fetters et al., U.S. Pat. No. 3,985,830; Milovich, Canadian Pat. No. 716,645; and British Pat. No. 1,025,295. They are usually compounds having at least two non-conjugated alkenyl groups. Such groups are usually attached to the same or different electron withdrawing groups, e.g., an aromatic nucleus. Such compounds have the property that at least two of the alkenyl groups are capable of independent reaction with different living polymers.

In the instant additive polymer compositions the preferred "star polymers" are star branched hydrogenated isoprenes. Hydrogenated star branched isoprene are commercially available. Examples of commercially available hydrogenated star branched isoprenes polymers that can be used in the instant compositions include, but are not limited to, the SHELLVIS 200 series, such as SHELLVIS 250, SHELLVIS 200, and SHELLVIS 260.

Solid polymer blends comprising shear stable and/or non shear stable partially crystalline linear olefin copolymers with star polymers have been found to give good dimensional stability, excellent shear stability and satisfactory solubility in mineral oils. The present polymer additive blends are viscosity index improvers and provide improved low temperature properties to motor oils and do not show adverse reactivity with other components. The aforementioned additive polymer compositions may be added to a major portion of lubricating oil (base oil) resulting in a composition comprising a major portion of lubricating oil (base oil) and a minor portion of lubricant additive composition. With respect to the present invention a major portion is considered to be 80- 90 wt % while a minor portion is 1-20 wt %.

One embodiment of this invention relates to polymeric additive compositions comprising a mixture of at least one crystalline ethylene-propylene copolymer (EPM) or ethylene-propylene-diene terpolymer (EPDM) with at least one star polymer which are useful for preparing shear stable VI improvers. Contrary to conventional shear stable amorphous OCPs, the instant blends show good dimensional stability when they preferably contain at least about 10 wt % of a crystalline OCP component. Preferred blends of crystalline OCPs and star polymers comprise from about 10 to 70 wt% crystalline OCP and from about 90 to 30 wt% star polymers, most preferred are about 20 to 60 wt% crystalline OCPs and about 80 to 40 wt% star polymers, most preferable are about 30 to 50 wt% crystalline OCPs and about 70 to 50 % star polymers.

Yet another embodiment of this invention relates to a lubricant additive composition, comprising a mixture of at least one amorphous and at least one crystalline olefin copolymers with at least one star polymer. Preferred blends comprise about 30 % crystalline OCP, about 50 % amorphous OCP and 20 % star polymers. More preferably about 20 to 60% crystalline OCP, about 30 to 70% amorphous OCP and 10 to 50% star polymers and most preferred is 30 to 50% OCP 20 to 40% amorphous OCP and 10 to 30 star polymers. The instant lubricant additive blends which include a crystalline olefin are easily shippable as solids and retain their dimensional stability. They provide enhanced low temperature (cold cranking) performance in motor oils, show good pour points, and satisfactory cold storage properties. Unlike the neat crystalline olefin copolymers, oil solutions of the blends do not require special handling, blending or storage facilities to achieve satisfactory performance.

Another embodiment of this invention relates to compositions comprising amorphous EPM or EPDM with star polymers. Preferred blends comprises about 10 to 90wt% amorphous OCPs and 90 to 10wt% star polymers. Most preferred is about 20 to 60wt% amorphous OCPs and about 80 to 40 wt% star" polymer. Most preferable is about 30 to 50 wt% amorphous OCPs and 70 to 50wt% star polymer. Compared to neat amorphous OCP, these blends provide enhanced low temperature properties in motor oils.

Several blends of olefin copolymers (EPM or EPDM) with star polymers were prepared by varying the polymer structure, functionality [non-dispersant (OCP) or dispersant (DOCP) or dispersant/antioxidant (DAOCP) ] , molecular weight and composition. Amorphous copolymers (OCP) , dispersant olefin copolymer (DOCP) or dispersant/antioxidant copolymers (DAOCP) were blended with both partially crystalline OCP consisting of approximately 75-80 mole% ethylene and with star branched isoprenes. The dimensional stability and physical properties of solutions of these blends in oil were determined. When mixtures of amorphous and crystalline OCPs are employed, the amount of amorphous to crystalline OCP in the mixture can be about 20 to 80, preferably about 30 to 70, most preferably 40 to 60.

The blends can be prepared by various conventional methods such as by devolatilization of blended polymer solutions or by blending of the solid rubbers in the mastificator, Brabender mixer or extruder.

One method is to mix solutions of the polymers and then to devolatilize the mixed solutions to produce a solid polymer blend. Another method is to mix solid polymers, referred to as rubbers, in a masticator, the Brabender Mixer, or an extruder. In the solution/devolatilization procedure, the solvent from the solution of the copolymer rubbers is removed by evaporation.

Oil concentrates of the dimensionally stable polymer blend are prepared as follows:

A base oil or a mineral lubricating oil or synthetic oil is heated to 80-300°F in a vessel equipped with a mechanical stirrer and a heating jacket. Pieces of the polymer blend, generally 1/2-inch cubes, are charged gradually to the oil forming a mixture. The mixture is stirred at 80-300°F until the rubber is completely dissolved, which may require from 1-24 hours. The polymer content may be adjusted to a required viscosity level.

Lubricating oils in which the multifunctional additives of this invention may find use may include automotive, aircraft, marine, railway, etc., oils; oils used in spark ignition or compression ignition; summer or winter oils, etc. Typically the lubricating oils may be characterized by a b.p. of about 570^βF. to about 660°F., preferably 610°F., an e.p. of about 750°F. to about 1200°F., preferably 1020^βF.; an API gravity of about 25 to about 31, preferably about 29.

A typical lubricating oil in which the polymer of this invention may be present may be automotive or diesel engine oil.

Having thus broadly described the present invention it is believed that the invention will become even more apparent by reference to the following examples. It will be appreciated, however that the examples are preserved solely for the purposes of illustration and should not be considered as limiting the invention. As is shown in the examples, the polymer blends of the invention show good dimensional stability and the performance of these blends provide enhanced low temperature (cold cranking) performance in motor oils, good pour points, and satisfactory cold storage properties.

Examples MATERIAL AND METHODS LABORATORY PREPARATION PROCEDURE OF POLYMER BLENDS

The equipment and dissolution procedure used for the preparation of OCP solid rubber blends is as follows:

Pieces of various polymers (~ iⁿ cubes) are charged gradually to a mixer fitted with a reflux condenser and containing a low boiling hydrocarbon solvent, typically n-hexane, cyclohexane or n-heptane.

The mixture is stirred at 60 to 80 C until the rubbers are completely dissolved (approx. 8 hours)

The solvent is removed by evaporation under vacuum. The polymer blend residue is tested for dimensional stability and the solution properties in oil are examined.

PREPARATION PROCEDURE OF POLYMER BLEND CONCENTRATES (VI IMPROVERS)

The equipment and dissolution procedure typically used for the manufacture of OCP VI improvers from solid rubber is used for the preparation of the VI improvers from polymer blends:

Base oil is heated to 80 - 300 F in a mixer equipped with a mechanical stirrer and heating jacket.

Pieces of polymer blend (~ #" cubes) are charged gradually to the mixer.

The mixture is stirred to 80 to 300 F until the rubber is completely dissolved (approx. 1 - 24 hours) .

The polymer content is adjusted to the required viscosity level. It can vary with molecular weight of the polymer and blend composition. The resulting concentrated solution is used "as is" for further testing. TESTS Dimensional Stability

Polymers are dissolved in n-heptane at 60 C for 8 hours at a temperature of 150 F in a mixer equipped with a mechanical stirrer, reflux condenser and heating jacket. Following complete dissolution of the polymers, the heptane is removed by evaporation under vacuum. A 1" cube is formed from the polymer blend residue and cooled to room temperature.

A l" cube of solid rubber is placed between two 3" x C aluminum plates at ambient temperature. The change in the dimensions of the polymer with time is observed and described as follows: excellent - no change good - slight change fair - significant change poor - flows

Physical Properties of Polvmer Concentrated Solutions (VI Improvers)

Standard Texaco or ASTM test methods were used for the evaluation of the physical properties of the VI improvers.

Shear Stability Index

Shear Stability Index (SSI) is determined as

SSI = Vbs - Vas _{x l00%} TP where Vbs and Vas are viscosities of polymer solution before and after shearing, respectively.

TP is the thickening power measured by the difference between Vbs and solvent viscosity.

(Vbs - Vas) x 100% is viscosity loss determined VBS according to the ASTM Method D-3945 (Proc. A) . Bench Dispersancv

The sample VI improver is blended into a formulated oil, which does not contain a dispersant, to make a 10 wt% VI improver solution. The blend is then tested for dispersancy in the Bench VE Test.

In this test, dispersancy of the experimental oil is compared to that of three reference oils (which give excellent, good and fair results in the test) . The numerical value of a test result decreases with an increase in dispersant activity. A value around 190 indicates that the sample provides no dispersancy. Cold Storage Behavior of VI Improvers

The evaluation of the cold storage behavior of VI improvers and motor oils containing them was made by utilizing the Ultra Low Temperature Environmental Chamber (Thermotron S-8C) . This piece of equipment allows the determination of the stability of materials under cold temperature conditions. Such conditions were simulated by programming temperatures between -60 and 4 deg. F using an 18 hour time cycle. The samples were examined at 10 degrees Fahrenheit after 8 weeks of storage under these conditions.

Polymer blends were prepared using different ratios of a partially crystalline ethylene copolymer, amorphous ethylene copolymer and star isoprenes, SHELLVIS 250 or SHELLVIS 200. The components used and their properties are listed in Table I.

Polymer A is a blend consisting of 40 wt% of partially crystalline ethylene-propylene-diene terpolymer containing approximately 77-80 mole % ethylene, about 0.1- 1.0 weight percent diene monomer, with the balance being propylene, and 60 wt% of amorphous ethylene-propylene diene terpolymer containing 56-62 mole % ethylene, about 0.1-0.5 weight percent diene monomer and the balance propylene. A number average molecular weight as measured by GPC of approximately 43,000, a molecular weight distribution of approximately 3.2, and a crystallinity of about 4%.

Polvmer B is a commercial polymer, SHELLVIS 250, having a star branch structure with polyisoprene branches attached to a central core.

Polvmer C is a commercial polymer, SHELLVIS 200, having a star branch structure with polyisoprene branches attached to a central core. The molecular weight of this polymer is lower than that of Polvmer B.

Polymer D is a partially crystalline ethylene- propylene-diene terpolymer containing approximately 77-80 mole % ethylene, about 0.1-1.0 weight percent diene monomer, and the balance propylene. A number average molecular weight as measured by GPC of approximately 100,000, a molecular weight distribution of approximately 2.2, and a crystallinity of about 9%.

Polymer E is an amorphous ethylene-propylene- diene terpolymer containing 56-62 mole % ethylene, about 0.1-1.0 weight percent piece monomer, and the balance propylene. A number average molecular weight as measured by GPC of approximately 70,000, and a molecular weight distribution of approximately 2.2.

Polymer F is a blend consisting of 20 wt% of partially crystalline ethylene-propylene-diene terpolymer containing approximately 77-80 mole % ethylene, about 0.1- 1.0 weight percent diene monomer, and the balance propylene, and of 80 wt% dispersant amorphous ethylene- propylene-diene terpolymer containing 56-62 mole % ethylene, and about 2 wt% of pendant units derivatized from N-vinylpyrrolidone. A number average molecular weight as measured by GPC is approximately 70,000, a molecular weight distributions of approximately 2.01, and a crystallinity of about 3%.

Polvmer G is a dispersant amorphous ethylene- propylene-diene terpolymer containing 56-62 mole % ethylene, about 0.1-1.0 weight percent diene monomer, and about 2 wt% of pendant units derivatized from N- vinylpyrrolidone. A number average molecular weight as measured by GPC is approximately 70,000, a molecular weight distribution of approximately 2.1.

Polymer H is a dispersant/antioxidant amorphous ethylene-propylene copolymer containing 56-62 mole % ethylene, and about 1 wt% of pendant units derivatized from maleic anhydride and N-phenyl-p-phenylenediamine. A number average molecular weight as measured by GPC of approximately 70,000, a molecular weight distribution of approximately 1.9.

POLYMER DIMENSIONAL DESIGNATION POLYMER TYPE Mn Pd STABILITY SSI

A Linear OCP 70,000 2.5 good 24 Crystalline Blend

B star SHELLVIS 250 - - fair 10

C star SHELLVIS 200 - - fair 4

D Linear OCP 108,000 1.6 good 22 Crystalline

E Linear OCP 71,000 1.8 poor 24 Amorphous

F Linear DOCP 99,000 2.2 good 32 Crystalline Blend

G Linear DOCP 78,000 1.7 fair- (sticky) 25 Amorphous

H Linear DAOCP 90,000 2.1 good (sticky) 24 Amorphous

EXAMPLE I

Polymer blends were prepared using different ratios of a partially crystalline ethylene copolymer blend, designated Polvmer A, and of star polymer (SHELLVIS 250) designated Polymer B. The resulting blends were tested for dimensional stability in the Dimensional Stability Test and for shear stability in the Shear Stability test. The results were compared to the individual polymers: Polymer A and Polvmer B (Table II)

Table li SAMPLES OF EXAMPLE I

Run Polymer A Polymer B Dimensional __# wt% wt% Stability SSI

1 20 80 fair 13*

2 40 60 fair+ 16*

3 60 40 good 18

4 80 20 very good 22 A 100 excellent 24 B - 100 fair- 10

♦calculated

Example II

Polymer blends were prepared using different ratios of a partially crystalline ethylene copolymer blend, designated Polymer A, and of star polymer (SHELLVIS 200) designated Polymer C. The resulting blends were tested for dimensional stability in the Dimensional Stability Test and shear stability in the Shear Stability test. The results were compared to the individual polymers: Polymer A and Polymer C (Table III)

Table III. SAMPLES OF EXAMPLE II

Run Polymer A Polymer C Dimensional # wt% wt% Stability SSI

5 20 80 fair 8* 6 40 60 fair+ 12*

7 60 40 good 16*

8 80 20 very good 20* A 100 excellent 24 C - 100 fair- 4

♦calculated Example III

Polymer blends were prepared using 60 wt% of a partially crystalline ethylene copolymer, designated Polymer D, and 40 wt% of star polymer (SHELLVIS 250) designated Polymer B. The resulting blends were tested for dimensional stability in the Dimensional Stability Test. The Shear Stability Index was calculated from the blend components. The results were compared to the individual polymers: Polymer D and Polymer B (Table IV) Tftble IV, SAMPLES OF EXAMPLE III

Run Polymer D Polymer B Dimensional # wt% wt% Stability SSI

9 60 40 good 17*

D 100 excellent 22

B - 100 fair- 10

♦calculated Example IV

Polymer blends were prepared using 60 wt% of a amorphous OCP designated Polymer E, and 40 wt% of star polymer (SHELLVIS 250) designated Polymer B. The resulting blends were tested for dimensional stability in the Dimensional Stability Test. The Shear Stability Index was calculated from the blend components. The results were compared to the individual polymers: Polymer E and Polymer B (Table V)

Table V. SAMPLES OF EXAMPLE IV

Run Polymer E Polymer B Dimensional # wt% wt% Stability SSI

10 60 40 poor 21

E 100 poor 24

B _ 100 fair- 10

Example V

Polymer blends were prepared using 80 and 90 wt% of a dispersant crystalline OCP blend, designated Polymer F, and the balance of star polymer (SHELLVIS 250) designated Polymer B. The resulting blends were tested for dimensional stability in the Dimensional Stability Test. The shear stability was calculated from the blend components. The results were compared to the individual polymers: Polymer F and Polymer B (Table VI) Table VI. SAMPLES OF EXAMPLE V

Run Polymer F Polymer B Dimensional # wt% wt% Stability SSI

11 80 20 good 28*

12 90 10 good 30*

(slightly sticky)

F 100 poor 32

(slightly sticky)

B - 100 fair- 10

♦calculated

Examp! Le VI

Polymer blends were prepared using 80 wt% of a dispersant amorphous OCP, designated Polymer G, and 20 wt% of star polymer (SHELLVIS 250) designated Polymer B. The resulting blends were tested for dimensional stability in the Dimensional Stability Test. The shear stability was calculated from the blend components. The results were compared to the individual polymers: Polymer G and Polymer B (Table VII)

Table VII. SAMPLES OF EXAMPLE VI

Run Polymer G Polvmer B Dimensional # wt% wt% Stability SSI

13 80 20 fair - 19*

(slightly sticky)

100 poor 24 (sticky)

B 100 fair- 10

♦calculated Example VII

Polymer blends were prepared using 80 wt% of a dispersant/antioxidant amorphous OCP, designated Polymer H, and 20 wt% of star polymer (SHELLVIS 250) designated Polymer B. The resulting blends were tested for dimensional stability in the Dimensional Stability Test. The shear stability was calculated from the blend components. The results were compared to the individual polymers: Polymer H and Polymer B (Table VIII) Table VIII. SAMPLES OF EXAMPLE VII

Run Polymer H Polymer B Dimensional # wt% wt% Stability SSI

14 80 20 good 20 15 90 10 (slightly 21 sticky)

H 100 - good 24 (sticky)

B - 100 fair- 10

Example VIII

In this example the solution of samples of Example I, Run # 3 and 4, as well of the reference polymers A and B in solvent neutral oil (SNO-100) were prepared. These solutions are then diluted with a pour depressed SNO-130 to give a Kinematic Viscosity approx. 11.5 cSt. The properties of diluted samples are shown in TABLE IX

Table IX. SOLUTION PROPERTIES OF SAMPLES OF EXAMPLE I Sample 1-3 1-4 A B

Kin. Viscosity 100 11.3 11.4 11.5 11.5

100°C, cSt ASTM D-445

Shear Stability 18 22 24 4

Index (SSI)%,

ASTM D-3495(A)

Cold Cranking 3500 3400 3600 3200

Simulator (CCS) 25°C, CP, ASTM D-2602

Pour Point, °C -36 -33 -30 -36

ASTM D-97

MRV-TP-1, -30°C, cP 16,300+ 16,100+ 17,000+ 14,600+ ASTM D-4684

Brookfield Vise. 23,250 27,150 38,000 24,250 30°C, cP

♦ no yield stress

Example IX

In this example the solution of samples of Example II, Run #7 and 8, as well of the reference polymers A and C in solvent neutral oil (SNO-100) were prepared. These solutions are then diluted with a pour depressed SNO-130 to give a Kinematic Viscosity approx. 11.5 cst. The properties of diluted samples are shown in TABLE X.

Table X. SOLUTION PROPERTIES OF S.AMPLES OF EXAMPLE II Sample II -7 II -8 A C

Kin. Viscosity 11.4 11.4 11.5 11.5

100°C, cSt ASTM D-445

Shear Stability 18 22 24 10

Index (SSI)% ASTM D-3495(A)

Cold Cranking 3500 3600 3600 3200

Simulator (CCS) , -25°C, Cp ASTM D-2602

Pour Point, °C -33 -30 -30 -36

ASTM D-97

MRV-TP-1,-30°C, CP 13,000 15,200* 17,000* 14,200 ASTM D-4684

Brookfield Vise. 28,150 30,800 38,000 24,250 30°C, CP

* no yield stress

Example X

In this example the solution of samples of Example III, Run # 9, as well of the reference polymers D and B in solvent neutral oil (SNO-100) were prepared. These solutions are then diluted with a pour depressed SNO-130 to give a Kinematic Viscosity approx. 11.5 cSt. The properties of diluted samples are shown in TaABLE XI.

Table XI. SOLUTION PROPERTIES OF SAMPLES OF EXAMPLE III

Sample III-9 D B

Kin. Viscosity 11.4 11.5 11.5

100°C, cSt ASTM D-445

Shear Stability 21 22 10

Index (SSI) ASTM D-3495(A)

Cold Cranking 3150 3200 3100

Simulator (CCS) - 25°C, cP ASTM D-2602

Pour Point, °C -27 -24 -36

ASTM D-97

MRV-TP- 1 , 30°C , 14,400 16,700 14,200 Vis., cP

Yield Stress, Pa 0 70 0 ASTM D-4684

Brookfield Vise. 32,250 58,250 24,250 30°C, cP

Example XII

In this example the solution of samples of Example IV, Run #10, as well of the reference polymers E and B in solvent neutral oil (SNO-100) were prepared. These solutions are then diluted with a pour depressed SNO-130 to give a Kinematic Viscosity approx. 11.5 cSt. The properties of diluted samples are shown in TABLE XII.

Table XII. SOLUTION PROPERTIES OF SAMPLES OF EXAMPLE IV

Sample IV-10 E B

Kin. Viscosity 11.4 11.8 11.5

100°C, cSt ASTM D-445

Shear Stability 20 24 10

Index (SSI) , % ASTM D-3495(A)

Cold Cranking 3650 3800 3100

Simulator (CCS) - 25°C, cP ASTM D-2602

Pour Point, °C -36 -39 -36

ASTM D-97

MRV-TP- 1 , 30°C, 19,000 14,000 14,200 Vis., CP

Yield Stress, Pa 0 70 0 ASTM D-4684

Brookfield Vise. 24,050 30,000 24,250 30°C, cP

Example XII

In this example the solution of samples of Example V, Run #11 and Run #12, as well as of the reference polymers F and B in solvent neutral oil (SNO- 100) were prepared. These solutions are then diluted with a pour depressed SNO-130 to give a Kinematic Viscosity approx. 11.5 cSt. The properties of diluted samples are shown in TABLE XIII.

Table XIII. SOLUTION PROPERTIES OF SAMPLES OF EXAMPLE V Sample V-ll V-12 F B

Kin. Viscosity 11.5 11.5 11.5 11.5

100°C, CSt ASTM D-445

Shear Stability 28 30 34 10

Index (SSI) , %, ASTM D-3495(A)

Cold Cranking 3550 3600 3500 3100

Simulator (CCS) , - 25°C, cP ASTM D-2602

Pour Point, °C -33 -33 -33 -36

ASTM D-97

Brookfield Vise. 29,900 25,150 33,300 24,250 30°C, cP

Example XIII

In this example the solution of samples of Example VI, Run #13, as well as of the reference polymers G and B in solvent neutral oil (SNO-100) were prepared. These solutions are then diluted with a pour depressed SNO-130 to give a Kinematic Viscosity approx. 11.5 cSt. The properties of diluted samples are shown in TABLE XIV.

Table XIV. SOLUTION PROPERTIES OF SAMPLES OF EXAMPLE VI Sample VI -13 G B

Kin. Viscosity 11.4 11.8 11.5

100°C, cSt ASTM D-445

Shear Stability 18 23 10

Index (SSI), %, ASTM D-3495(A)

Cold Cranking 3850 VE* 3100

Simulator (CCS) - 25°C, cP ASTM D-2602

Pour Point, °C -33 -33 -36

ASTM D-97

MRV-TP- 1 , 30°C , 23,700 19,600 14,200 Vis., cP Yield Stress, Pa 0 70 0

ASTM D-4684

Brookfield Vise. 24,050 35,800 24,250 30°C, CP

* viscoelastic

Example XIV

In this example the solution of samples of Example VII, Run #14 and Run #15, as well as of the reference polymer H and B in solvent neutral oil (SNO-100) were prepared. These solutions are then diluted with a pour depressed SNO-130 to give a Kinematic Viscosity approx. 11.5 cSt. The properties of diluted samples are shown in TABLE XV. Table XV. SOLUTION PROPERTIES OF SAMPLES OF EXAMPLE VII Sample VII-14 VII-15 H B

Kin. Viscosity 11.5 11.5 11.5 11.5 100°C, CSt ASTM D-445

Shear Stability 20 21 24 10 Index (SSI) , %, ASTM D-3495(A)

Cold Cranking 3800 3850 3900 3100 Simulator (CCS) - 25°C, cP ASTM D-2602

Pour Point, °C -33 -33 -33 -36 ASTM D-97

Brookfield Vise. 34,450 27,600 44,400 24,250 30° C, cP

RESULTS The results shown in the attached tables indicate that the products of this invention, blends of crystalline and amorphous EPM or EPDM or crystalline EPM or EPDM with star branched polyisoprene form solid polymers with excellent dimensional stability. In addition, the functional OCPs, such as crystalline dispersant OCP (DOCP) or crystalline or amorphous dispersant/antioxidant (DAOCP) can also form dimensional stable material when blended with star branched polyisoprenes. Addition of the star polymer decreases the stickiness of the functional amorphous linear OCPs. The dimensional stability depends upon the blend composition. These polymer blends give shear stable VI improvers and motor oils with superior low temperature properties over neat amorphous OCPs. Compared to the blends consisting only of crystalline and amorphous linear OCPs, the blends containing star polyisoprene give products with significantly better pour points and Brookfield Viscosities. The appearance during the extended cold storage is satisfactory for both neat VI improvers and fully formulated oils containing them.

.Although the present invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be obvious that certain changes and modifications may be practiced within the scope of appended claims.

Claims

We Claim:

1. A polymer additive composition comprising at least one crystalline olefin copolymer and at least one star branched isoprene polymer.

2. The composition of claim 1 wherein said composition comprises 10-70% crystalline olefin copolymers and about 30-90% star polymer.

3. The composition of claim 2 wherein said composition comprises about 20-60% crystalline olefin copolymer and about 40-80% star polymers.

4. The composition of claim 3 wherein said composition comprises about 30-50% crystalline olefin copolymer and about 50-70% star polymers.

5. The composition of claim 1 wherein said olefin copolymer is ethylene-propylene copolymer or ethylene-propylene diene terpolymer, or combinations thereof.

6. The composition of claim 1 wherein said olefin copolymer is dispersant olefin copolymer or dispersant anti-oxidant copolymers or combinations thereof.

7. The composition of claim 1 wherein said star branched isoprene is SHELLVIS 200 or SHELLVIS 250.

8. A polymer additive composition comprising at least one amorphous olefin copolymer and at least one crystalline olefin copolymer and at least one star branched isoprene polymer.

The composition of claim 8 wherein said composition comprises about 10-60% crystalline olefin copolymer, 20-80% amorphous olefin copolymer and 10-70% star branched isoprene polymer.

10. The composition of claim 9 wherein said composition comprises about 20-60% crystalline olefin copolymer, 30-70% amorphous olefin copolymer and 10-50% star branched isoprene polymer.

11. The composition of claim 10 wherein said

10 composition comprises about 30-50% crystalline olefin copolymer, 20-40% amorphous olefin copolymer and 10-50% star branched isoprene polymer.

12. The composition of claim 8 wherein said

15 olefin copolymers are ethylene-propylene copolymer or ethylene-propylene diene terpolymer, or combinations thereof.

13. The composition of claim 8 wherein said

20 olefin copolymers are dispersant olefin copolymer or dispersant anti-oxidant copolymers or their combinations with crystalline or amorphous olefin coppolymers.

14. The composition of claim 8 wherein said

*⁵ star branched isoprene polymer is SHELLVIS 200 or SHELLVIS 250.

15. A polymer additive composition comprising at least one amorphous olefin copolymer and at least one

30 star branched isoprene polymer.

16. The composition of claim 15 wherein said composition comprises about 10-90% amorphous olefin copolymer and about 10-90% star polymer. 5

17. The composition of claim 16 wherein said composition comprises about 20-60% amorphous olefin copolymer and about 40-80% star polymer.

18. The composition of claim 17 wherein said composition comprises about 30-50% amorphous olefin copolymer and about 70-50% star polymer.

19. The composition of claim 15 wherein said olefin copolymer is ethylene-propylene copolymer or ethylene-propylene diene terpolymer, or combinations thereof.

20. The composition of claim 15 wherein said olefin copolymer is dispersant olefin copolymer or dispersant anti-oxidant copolymers or their combinations with crystalline or amorphous olefin copolymer.

21. The composition of claim 15 wherein said star branched isoprene polymer is SHELLVIS 250 or SHELLVIS 200.

22. A lubricating oil additive composition comprising a major portion of lubricating oil and minor amounts of polymer additive compositions comprising at least one crystalline olefin copolymer and at least one star branched isoprene polymer.

23. The composition of claim 22 wherein said polymer additive composition comprises about 10-70% crystalline olefin copolymer and about 30-90% star branched polyisoprene polymer.

24. The composition of claim 23 wherein said polymer additive composition comprises about 20-60% crystalline olefin copolymer and about 40-80% star branched polyisoprene polymer.

25. The composition of claim 24 wherein said polymer additive composition comprises about 30-50% crystalline olefin copolymers and about 50-70% star branched polyisoprene copolymers.

26. A lubricating oil additive composition comprising a major portion of lubricating oil and minor amounts of polymer additive compositions comprising at least one amorphous olefin copolymer and at least one star branched isoprene copolymer.

27. The composition of claim 26 wherein said polymer additive composition comprises about 10-90% crystalline olefin copolymer and about 10-90% star branched polyisoprene copolymer.

28. The composition of claim 27 wherein said polymer additive composition comprises about 20-60% crystalline olefin copolymer and about 40-80% star branched polyisoprene copolymer.

29. The composition of claim 28 wherein said polymer additive composition comprises about 30-50% crystalline olefin copolymer and about 50-70% star branched polyisoprene polymer.

30. A lubricating oil additive composition comprising a major portion of lubricating oil and minor amounts of polymer additive compositions comprising at least one amorphous olefin copolymers and crystalline olefin copolymer and at least one star branched isoprene polymer.

31. The composition of claim 30 wherein said polymer additive composition comprises about 30-50% crystalline olefin copolymer, 20-40% amorphous olefin copolymers and 10-50% star branched isoprene polymer.

32. Dimensionally stable polymer blend comprising at least one crystalline olefin copolymer and at least one star branched isoprene polymer.

33. Dimensionally stable polymer blend comprising at least one crystalline olefin copolymer and at least one amorphous olefin copolymer at at least one star branched isoprene polymer.

34. The dimensionally stable polymer blend of claim 32, wherein said crystalline olefin copolymer is a dispersant olefin copolymer or dispersant antioxidant copolymer.

35. The dimensionally stable polymer blend of claim 33, wherein said crystalline olefin copolymer is a dispersant olefin copolymer or dispersant antioxidant copolymer.

36. The dimensionally stable polymer blend of claim 33, wherein said amorphous olefin copolymer is a dispersant olefin copolymer or dispersant antioxidant copolymer.