SUCCINIMIDE DERIVATIVES OF A COPOLYMER OF ETHYLENE AND ALPHA-OLEFIN

DERIVES SUCCINIMIDIQUES D'UN COPOLYMERE DE L'ETHYLENE ET D'UNE ALPHA-OLEFINE

English Abstract

Abstract of the Disclosure
Succinimide derivatives of copolymers of ethylene
and an alpha-olefin, such as ethylene-propylene copolymer,
are useful as shear stable viscosity index (VI) improvers
and dispersants in lubricating oils. Especially useful is
the N-(3-dimethylaminopropyl) succinimide of the copolymer
of ethylene and an alpha-olefin, such as ethylene-propylene
copolymer. This succinimide is obtained by reacting
ethylene-propylene copolymer in a solvent, such as chloro-
benzene, with maleic anhydride and a peroxide, such as
dicumylperoxide. The resulting succinic anhydride is then
reacted with 3-dimethylaminopropylamine to produce the
resulting dimethylaminopropyl succinimide derivatives of the
ethylene-propylene copolymer. The succinimide derivatives
of this invention are advantageously incorporated in minor
amounts, such as in the range 0.05-10% by weight based on
the overall composition, in lubricating oils, such as
petroleum based automotive lubricating oils, to improve the
physical properties thereof. For example, the succinimide
derivatives of this invention, when added to petroleum based
lubricating oils, act as shear stable VI improvers and
dispersants.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A succinimide derivative of a copolymer of ethylene and
an alpha-olefin wherein the derivative contains from about 0.02
by weight nitrogen to about 1.0% by weight nitrogen.
2. A succinimide derivative in accordance with claim 1
wherein the nitrogen content is from 0.05 to 0.5% by weight.
3. A succinimide derivative in accordance with claim 1
wherein said alpha-olefin is propylene.
4. A succinimide derivative in accordance with claim 1
wherein the derivative is the dimethylaminopropyl-succinimide
derivative.
5. A succinimide derivative in accordance with claim 1
wherein the derivative is the dimethylaminopropyl-succinimide
derivative of ethylene-propylene copolymer.
6. A succinimide derivative in accordance with claim 5
wherein the derivative contains from about 0.2% by weight
nitrogen to about 0.3% by weight nitrogen.
7. A succinimide derivative of a copolymer of ethylene and
an alpha-olefin wherein the derivative is a polyamine succinimide
derivative, the polyamine being selected from the group of
polyamines having the formula:
(A) <IMG>
18

(B) <IMG> and
(C) <IMG>
wherein Rl and R2 are the same or different and are an alkyl
radical having 1 to 4 carbon atoms, R3, R6 and R7 are the same
or different and are a methylene radical having 1 to 4 carbon
atoms, R4 and R5 are the same or different and are a methylene or
a methine radical having 1 to 4 carbon atoms, Xl is 0, N, S,
CH2 if R4 and R5 are methylene radicals or CH if R4 and R5 are
methine radicals and X2 is 0, N, N-Rl, S or CH2 and Rl has the
value given above.
8. A lubricating oil composition comprising a minor amount
of the succinimide derivative in accordance with claim 3.
9. A lubricating oil composition comprising a minor amount
of the succinimide derivative in accordance with claim 4.
10. A lubricating oil composition comprising about 0.05 -
10% by weight of the succinimide derivative in accordance with
claim 1.
11. A lubricating oil composition comprising about 0.05-
10% by weight of the succinimide derivative in accordance with
claim 3.

12. A lubricating oil composition comprising about 0.05-
10% by weight of the succinimide derivative in accordance with
claim 4.
13. A lubricating oil composition comprising about 0.5-
2.50% by weight of the succinimide derivative in accordance
with claim 5.
14. A lubricating oil composition in accordance with claim
8, 9 or 10 wherein said lubricating oil is a petroleum based
lubricating oil.
15. A lubricating oil composition comprising a minor amount
of the succinimide derivative in accordance with claim 7.
16. A succinimide derivative of a copolymer of ethylene
and an alpha-olefin prepared by reacting said ethylene-alpha-
olefin copolymer with maleic anhydride in the presence of a
free radical initiator and a solvent for the reaction mixture
to produce a resulting alkyl succinic anhydride derivative of
said ethylene-alpha-olefin copolymer, adding an inert liquid
diluent to the resulting reaction mixture containing said alkyl
succinic anhydride derivative, removing remaining maleic anhyd-
ride and solvent from the resulting reaction mixture, reacting
the alkyl succinic anhydride derivative therein with a polyamine
selected from the group of polyamines having the formula:
(A) <IMG>,

<IMG>
(B) and
(C) <IMG>
wherein R1 and R2 are the same or different and are an alkyl
radical having 1 to 4 carbon atoms, R3, R6 and R7 are the same
or different and are a methylene radical having 1 to 4 carbon
atoms, R4 and R5 are the same or different and are a methylene
or a methine radical having 1 to 4 carbon atoms, X1 is O, N, S,
CH2 if R4 and R5 are methylene radicals or CH if R4 and R5 are
methine radicals and X2 is 0, N, N-R1, S or CH2 and R1 has the
value given above, to produce the corresponding succinimide
derivative of said ethylene-alpha-olefin copolymer containing
from about 0.02 to about 1.0% by weight nitrogen.
17. A succinimide derivative according to claim 16 wherein
the nitrogen content is from about 0.05 to 0.5% by weight.
18. A lubricating oil composition comprising therein the
succinimide derivative of claim 16 or 17 in an amount in the
range 0.05-10% by weight based on said composition.
19. A method of preparing a succinic derivative of a co-
polymer of ethylene and an alpha-olefin comprising reacting said
ethylene-alpha-olefin copolymer with maleic anhydride in the
presence of a free radical initiator and a solvent at a temper-
ature in the range of 80-130°C for the reaction mixture to pro-
21

duce a resulting alkyl succinic anhydride derivative of said
ethylene-alpha-olefin copolymer, adding an inert liquid diluent
to the resulting reaction mixture containing said alkyl succinic
anhydride derivative, removing remaining maleic anhydride and
solvent from the resulting reaction mixture and reacting the
alkyl succinic anhydride derivative therein with a polyamine
selected from the group of polyamines having the formula:
(A) <IMG>
(B) <IMG> and
(C) <IMG>
wherein R1 and R2 are the same or different and are an alkyl
radical having 1 to 4 carbon atoms, R3, R6 and R7 are the same
or different and are a methylene radical having 1 to 4 carbon
atoms, R4 and R5 are the same or different and are a methylene
or methine radical having 1 to 4 carbon atoms, Xl is 0, N, S,
CH2 if R4 and R5 are methylene radicals or CH if R4 and R5 are
methine radicals and X2 is 0, N, N-Rl, S or CH2 and Rl has the
22

value given above to produce the corresponding succinimide de-
rivative of said ethylene-alpha-olefin copolymer.
20. A method in accordance with claim 19 wherein said alpha-
olefin is propylene.
21. A method in accordance with claim 19 wherein said sol-
vent is an aromatic solvent.
22. A method in accordance with claim 19 wherein said sol-
vent is benzene.
23. A method in accordance with claim 19 wherein said sol-
vent is chlorobenzene.
24. A method in accordance with claim 19 wherein said free
radical initiator is benzoyl peroxide.
25. A method in accordance with claim 19 wherein said free
radical initiator is peroxide.
26. A method in accordance with claim 19 wherein said free
radical initiator is dicumylperoxide.
27. A method in accordance with claim 19 wherein said
diluent is a high boiling point petroleum based oil.
28. A method in accordance with claim 19 wherein said poly-
amine is 3-dimethylamino-1-propylamine.
29. A method in accordance with claim 19 wherein said poly-
amine is 2-aminopyridine.
30. A method in accordance with claim 19 wherein said poly-
amine is N-(3-aminopropyl) morpholine.
31. An oil additive concentrate comprising a hydrocarbon
23

solvent and about 5-30% by weight based on the solvent of the
succinimide derivative of claim 1.
32. An oil additive concentrate comprising a hydrocarbon
solvent of lubricating oil quality and about 5-10% by weight
based on the solvent of the succinimide derivative in accordance
with claim 7.
33. An oil additive concentrate in accordance with claim
31, wherein the succinimide derivative is present in the range
about 10-15% by weight.
24

Description

;``~
36
This invention relates to novel compounds oradducts, and methods of preparing the same, useful as addi-
tives for lubricating oils, particularly petroleum based
automotive lubricating oils, to impart shear stability, im-
proved viscosity index (VI) and dispersancy in lubricating
oil compositions containing the same.
Various compositions and adducts are known and
have been employed to improve the viscosity index and dis-
persancy in lubricating oil compositions containing the
same, see particularly U. S. Patents 3,179,716, 3,316,177,
3,329,658, 3,413,104, 3,449,250, 3,471,458, 3,496,249 and
3,513,095.
Ethylene-propylene copolymers have been employed
in lubricating oil compositions as ashless sh~ar stable VI
improvers. These copolymers, however, do not act to any
substantial degree as dispersants in lubricating oil com-
positions containing the same.
It is an object of this invention to provide
compounds or materials, and methods of preparing the same,
useful as additives to lubricating oils.
It is another object of this invention to provide
compounds and materials useful as shear stable VI improvers
and dispersants when incorporated in lubricating oils,
particularly petroleum based automotive lubricating oils.
~ '
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It is still another object of this inYention to provide
derivatives of ethylene-propylene copolymers which are useful
as lubricating oil additives.
Yet another object of this invention is to provide a
method of preparing compounds or materials useful as shear stable
VI improvers and dispersants, when incorporated in lubricating
oils, preferably petroleum based automotive lubricating oils.
Also, another object of this invention is to provide
petroleum based automotiYe lubricating oils.
Accordingly, one aspect of the invention provides a
succinimiae derivative of a copolymer of ethylene and an alpha-
olefin wherein the derivative contains from about 0.02% by
weight nitrogen to about 1.0~ by weight nitrogen.
Thus, it has been discovered that succinimide derivatives
of copolymers of ethylene and an alpha-olefin, such as ethylene-
propylene copolymer, are useful as shear stable VI improvers
and dispersants in lubricating oils, particularly petroleum
based automotive lubricating oils. Especially useful is the
N-(3-dimethylaminopropyl) succinimide of the copolymer of
ethylene and an alpha-olefin, such as ethylene-propylene copoly-
mer. This succinimide is obtained by reacting ethylene-alpha-
olefin copolymer, such as ethylene-propylene copolymer, in a
solvent with maleic anhydride in the presence of a free radical
initiator, such as peroxide, e.g. benzoyl peroxide, dicumul-
peroxide and the like.
-- 3 --
~ .
.- . -- - . . : .

4~?!~6
The resulting alkyl succinic anhydride derived by the
addition of RH across the double bond of the maleic
anhydride, wherein R is an ethylenè-alpha-olefin copolymer
radical, such as ethylene-propylene copolymer radical, after
addition of a diluent oil and removal of excess maleic
anhydride and solvent is converted to the corresponding
N-(3-dimethylaminopropyl) succinimide by reaction with
3-dimethylamino-1-propylamine. Upon completion of the reac-
tion the excess amine is removed by distillation to yield
the resulting succinimide as product.
More particularly, and in accordance with one
embodiment of the practices of this invention directed to a
method of preparing the succinimide derivatives of the
copolymers of ethylene and an alpha-olefin, particularly
ethylene-propylene copolymer, a solution containing about
10-40% by weight ethylene-propylene copolymer, particularly
a narrow molecular weight distribution amorphous ethylene-
propylene copolymer of the type employed as a lubricating
oil additive, in a suitable solvent, such as an aromatic
solvent, e.g. benzene, chlorobenzene and the like, or in a
saturated, aliphatic or cycloaliphatic hydrocarbon solvent,
such as cyclohexane, is prepared. The resulting solution is
heated to a temperature of about 80-130C. in the presence of
added excess maleic anhydride and a small amount of a free
radical initiator, such as benzoyl peroxide or dicumylperoxide.
The resulting reaction product is the corresponding alkyl
s~ccinic anhydride derived by the addition of RH across the
double bond of the maleic anhydride, wherein R is an ethylene-
propylene copolymeric radical. There is added to the resulting
-4-
- . ,, , :
, : .

a~
reaction mixture a relatively high boiling, substantially
inert, diluent oil and the excess maleic anhydride and
solvent is removed by vacuum distillation. The remaining
polymer succinic anhydride, i.e. the succinic anhydride
grafted onto the ethylene-propylene copolymer, is converted
to the corresponding N-(3-dimethylaminopropyl) succinimide
by heating in the presence of an excess of the correspond-
ing polyamlne, viz. 3-dimethylamino-1-propylamine. Upon
completion of the reaction the excess amine is removed by
distillation and the resulting reaction product fil~ered.
As indicated hereinabove, it is preferred to employ
as the ethylene-alpha-olefin copolymer, ethylene-propylene
copolymer. In the practices of this invention it is
preferred to employ shear stable ethylene-propylene copolymer
of the type suitable for incorporation into a lubricating
oil as a VI improver. When shear stable ethylene-propylene
copolymer is employed in the above-described reaction for the
preparation of the succinimide derivative thereof the
resulting reaction product of this invention is also shear
stable.
In the preparation of the succinimide derivatives
of a copolymer of ethylene and an alpha-olefin in accordance
with this invention, it has been noted that to obtain optimum
dispersant characteri~tics when incorporated in a lubricating
oil, the amount of the free radical initiator, e.g. benzoyl
peroxide or dicumylperoxide, employed is desirably controlled
such that the final polymer succinimide product of this
invention contains in the range about 0.15-0.4% by weight
nitrogen to achieve optimum results when the resulting
-5-
. - . . ............... . .
. .

1~ ~4~fi
succinimide product is employed as a lubricating oil
additive. By way of illustration, there are set forth
in accompanying Table I test results with respect to the
polymer succinimides prepared in accordance with this
invention and having varying nitrogen content. The test
results based on the Bench Sludge Test II (BSII) and the
Resin Inhibition Test (RIT) indicate the minimum nitrogen
content for optimum dispersancy in lubricating oil com-
positions:
TABLE I
% (wt.) N in Polymer ~ (wt.) Polymer in Blend BSII RIT
0.09 1.5 2.2 30
0.11 " 1.5 27.5
0.15 " 1.7 29
0.19 " O.g 16
0.29 " o.a 13
0.19 1.0 1.0 50
0.29 " 1.5 47
0.37 " 1.4
RIT and BSII are minimized at 0.19-0.29% in the polymer.
Engine testing of the polymer succinimides of this
invention with respect to the dispersancy of the polymer
succinimides in lubricating oil compositions has also
indicated promising results. Engine testing of multigrade
petroleum based automotive lubricating oils containing
ethylene-propylene copolymer dimethyl~aminopropylsuccinimide
(E-P-DMAPS) as the sole VI improver therein and dispersant
gave excellent results. The motor oil compositions or blends
in accordance with this invention tested,in addition to
. , - . - . . . . .

9fi
containing the polymer succinLmides,also contained a
pour depressant additive, an overbased calcium sulfonate
detergent, a zinc dialkyldithiophosphate oxidation-corrosion
inhibitor and an antifoam additive, with the balance of the
blend or composition comprising solvent neutral oil.
The effectiveness of the reaction product of the
invention was determined by formulating a motor oil composi-
tion and t~sting it in the MS-VB Engine Test. The MS-VB
Engine Test was conducted in accordance with the detailed
procedures found in ASTM SpecialTechnical Bulletin No. 315-~,
"Engine Test Sequences for Evaluating Automatic Lubricants
for API Service MS," published by the American Society for
Testing Materials, 1916 Race Street, Philadelphia, Pa. 19103.
The MS-VB Engine Test is a low temperature, low speed
cycling test designed to determine the oil's ability to pre-
vent sludge drop-out and varnish formation in automobile
gasoline engines equipped with closed positive crankcase
ventil~tion. The test is cyclic in nature alternating
between operating and "soak" periods. At test termination
engine inspection according to standard procedures is con-
ducted in the completely disassembled engine and the results
of various lubricants compared accordingly.
The re3ults of these tests are set forth in
accompanying Table II.
TABLE II
N in Polymer 0.2 0.3
% Polymer in Blend 1.4 0.9
Vis. Grade lOW-40 lOW-30
Sludge 48.5 47.7
Varnish 39.8 36.7
Piston Skirt Varnish 7.8 7.4
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In the practices of this invention for the
preparation of the polymer succinimide, various solvents
have been disclosed as being useful in the initial reaction
wherein the ethylene-alpha-olefin is reacted with maleic
anhydride. In connection with this initial reaction it has
been mentioned that it is desirable, if not necessary, to
employ a large excess of maleic anhydride. An excess of
the polyamine,3-dimethylaminopropylamine,is also desirable,
if not necessary, in the second stage reaction wherein the
polymer succinic anhydride is converted to the corresponding
polymer succinimide. Excess maleic anhydride and 3-dimethyl-
aminopropylamine is necessary particularly when a saturated
cycloaliphatic hydrocarbon, such as cyclohexane, is employed
a~ the ~olvent due to significant side reactions between the
cyclohexane solvent, maleic anhydride and the polyamine.
It has been determined, however, that the excess
of both maleic anhydride and the polyamine, 3-dimethylamino-
propylamine,can be significantly reduced when an inert solvent,
such as an aromatic solvent, such as an aromatic hydrocarbon,
e.g. benzene, or chlorobenzene, is employed ag- solvent instead
of a saturated cycloaliphatic hydrocarbon 301vent, such as
cyc}ohexane. Indeed, by employing an inert solvent, such as
ch}orobenzene or benzene, the amount of 3-dimethylaminopropyl-
amine employed in the reaction for the preparation of the
polymer succinimide can be substantially reduced, such as to
an amount about 10% greater than the stoichiometric amount
required for complete reaction with the intermediate succinic
anhydride. This reduction in the amount of excess amine
required results in the elimination of the amine stripping
,
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4~9fi
step with consequent lower processing and manufacture costs
for the produced additi~e, the polymer succinimide. Also,
the final product, the polymer succinimide, contains a lower
amount of non-polymer nitrogen-containing or nitrogenous
impurities. When the polymer succinimide is prepared employ-
ing cyclohexane as the solvent there is present in the result-
ing product appreciable or substantial quantities of reaction
products derived from side reactions involving the solvent
cyclohexane, maleic anhydride and dimethylaminopropylamine.
The resulting side reaction products, when present in the
final product, tend to cause excessive corrosion in the
lubricating oil blends containing the product polymer
succinimide as an additive, based on engine tests, such as
tho CLR L-38 bearing corrosion test.
~ Illustrative o~ the advantages of the practices of
this invention there is set forth in accompanying Table III
results of tests showing the reduction in amounts of maleic
anhydride and 3-dimethylaminopropylamine employed in the
presently preferred practices of this invention when an
inert solvent, such as an inert aromatic solvent, e.g.
benzene, chlorobenzene and the like, is employed as compared
wlth a reactive solvent, such as cyclohexane.

~ 4~ fi
TA~LE I I I
- Process Solvents
Step Cyclohexane Chlorobenzene
Maleic
anhydride charge8 g/100 g polymer 2.7 g/100 g polymer
Dicumylperoxide
charge 0.3 g/100 g polymer 0.43 g/100 g polymer
3-Dimethylamino-
propylamine charge 8 g/100 g polymer 1.2 g/100 g palymer
Final amine Excess amine No stripping after
stripping stripped at 215C./ reaction with amine
20 mm ~g
The following is an example of the practices of this
invention.
Example
400 grams of ethylene-propylene copolymer ~molecular
weight range useful as a lube oil improver) solution contain-
ing 31 wt. % copolymer in hexane solution obtained from
Copolymer Rubber and Chemical Corp. and 550 grams of chloro-
benzene were combined. 330 grams of solvent were removed by
distillation from the resulting solution. There resulted a
solution containing 20 wt. % ethylene-propylene copolymer in
chlorobenzene. Upon cooling to about 130C., 3.35 grams of
maleic anhydride and 0.53 gram dicumylperoxide were added to
the ~olution. The resulting mixture was heated and maintained
at 130C. for 6 hours. Infrared examination of a sample of
the polymer separated by precipitation in boiling acetone
indicated that upon conversion to the succinimide the neat
polymer would contain 0.~0% nitrogen. 1116 grams of a high
boiling point inert, neutral diluent hydrocarbon oil were
added t~ the resulting solution and the chlorobenzene solvent
and exce~s unreacted maleic anhydride were remo~ed by
--10--

1~4~fi
stripping to a temperature of 180C. at an absolute
pressure of 0.08 mm Hg. Thereupon 0.605 gram of 3-dimethyl-
amlnopropylamine was added with stirring to 500 grams of the
resulting oil solution at a temperature of 125C. The
resulting stirred reaction admixture was maintained at 125C.
for 2 hours. The resulting produced polymer succinimide
product analyzed .033% nitrogen, the same as the theoretical
nitrogen content based on the a unt of amine added. The
polymer succinimide product was subjected to comparative
automotive engine oil evaluation tests with a polymer
succinimide prepared employing cyclohexane as the solvent
instead of an inert aromatic solvent, such as benzene. The
results of these tests are set forth in accompanying Table
IV. The test data presented therein indicate that both
productq are equivalent with regard to oil solution properties,
shear stability and dispersancy.
TABLE IV
1 Chlorobenzene Cyclohexane
Test Data Solvent Product Solvent Product
Orig. Vis., 100F., SUS 426 397
210F., SUS 69.0 68.6
FISST ~MS-103, 20 passes)
Vis., 210F., SUS 65.2 63.3
Vis., 210F., SUS 3.8 5.3
% Thickening
Power Loss, 210F.2 14 20
Pour Pt., F. -45 -45
CCS QF., c.p. 1580 1600
Bench Sludge I 0.4 0.4
II 0.4 0.9
Tested at 1.$ wt. % (neat polymer basis) in above-described
diluent oil.
The 210F. viscosity of the base oil (diluent oil) was
assumed to be 42.3 SUS for this calculation.
.. ., .. ~ ~

~ ~l4~
The polymer succinimide was also prepared employ-
ing benzene as the inert aromatic solvent, using also
dicumylperoxide as the radical initiator for the addition
of the ethylene-propylene copolymer to the maleic anhydxide.
The reaction was carried out at a temperature of about
130-132~C. under autogeneous pressure and the reactant ratios
were similar to those set forth hereinabove with respect to
the Example wherein chlorobenzene was employed as the solvent.
It was observed that the resulting produced polymer
succinimide exhibited oil solution properties, shear stabil-
ity and dispersancy at least eq~ivalent to the polymer
succinimide prepared with the use of chlorobenzene as the
aromatic solvent.
In the preparation of the polymex succinimide in
accordance with the practices of this invention it is
preferred to employ as the ethylene-alpha-olefin copolymer
a copolymer of ethylene-propylene. Desirably, the ethylene-
propylene copolymer employed in the preparation of the
polymer succinimides derived therefrom in accordance with the
practices of this invention is suitable per se as an additive
to petroleum based lubricating oils, such as VI improvers
therefor. Suitable such ethylene-propylene copolymers are
known and would have a molecular weight greater than about
2000, such as a molecular weight in the range 5,000-50,000
and higher. Alpha-olefins other than propylene are also
useful in the preparation of ethylene-alpha-olefin polymers
as copolymers employed in the practices of this invention.
Such alpha-olefins include bu~ene-l, pentene-l, hexene-l,
4-methyl-pentene-1 and the like. As indicated hereinabove,
however, e~hylene-propylene copolymers are preferred with a
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fi
molecular make-up such that the ethylene-propylene copolymers
contain in the range about 10-90 mol % ethylene and 90-10
mol % propylene, preferably in the range 30-70 mol ~ and
70-30 mol % propylene.
An amorphous ethylene-propylene copolymer which
serves as a viscosity index improvement additive in
lubricating oils and which is particularly useful in
accordance with the practices of this invention may be
prepared as described in U.S. Patent 3,522,180. Therein it
is disclosed that.the copolymer is prepared in a hydrogen-
moderated reaction at moderate temperatures and pressures
in the presence of a solvent soluble Ziegler-Natta catalyst.
Gaseous mixtures of propylene and ethylene together with
hydrogen are introduced into a reactor containing a solvent
which does not deactivate the catalyst, such as carbon
tetrachloride, hexane, n-heptane, benzene or cyclohexane.
Reaction temperatures in the range -40F. to about 250F.
and a pressure in the range 0 - 300 psi~ may be satisfactorily
employed. The two component Ziegler-Natta catalyst employed
comprises as the first component a hydrocarbyl vanadate, a
hydrocarboxy vanadyl halide or a vanadyltrihalide and as the
second component an alkyl al.uminum halide. Preferred catalyst
~ystems include tri-n-butyl orthovanadate as ~he ~irst
component and ethyl aluminum dichloride, diethylaluminum
chloride or ethyl aluminum ses~uichloride as the second
component.
The above-described Ziegler-Natta catalyst promoted
hydrogen moderated polymerization reaction i5 used to produce
ethylene-propylene copolymers having an amorphous structure,
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fi
by infrared analysis, a propylene content of 20 to 70
mol percent, a number average molecular weight between
about 10,000 and about 100,000 and a narrow molecular
weight distribution, measured by gel permeation chromo-
tography (GPC), of less than about 5. Not only do these
copolymers increase the viscosity index of lubricating
when added thereto but they exhibit a substantially high
resistance to the high shearing forces experienced in
lubricating service, which shearing forces often mechanically
degrade a long chain polymer.
Although in the practices of this invention it is
preferred to employ as the polyamine the compound 3-dimethyl-
amino-l-propylamine, other polyamines are useful.
Other useful polyamine~ in accordance with the
practices of this invention are identified by any of the
following structural formulae:
Rl
.: (A) ~N - R3 - NH
: R2
R4
~ (B) Xl N and
: ~ ~R;~NH2
, ~ .
: / 6~
(C~ X2 N - R3 - NH
R7
wherein Rl and R2 are the same or different and are an alkyl
radical having 1 to 4 carbon atoms, R3, R6 and R7 are the
: : same or different and are a methylene radical having 1 to 4
: carbon atoms, R4 and R5 are the same or different and are a
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fi
methylene or a methine radical having 1 to 4 carbon atoms,
Xl is O, N, S, CH2 if R4 and R5 are methylene radicals
or CH if R4 and R5 are methine radicals, and X2 is o, N,
N-Rl, S or CH2.
Examples of polyamines of formula A are:
3-dimethylamino-1-propylamine; 2-dimethylamino-1-ethylamine,
4-dimethylamino-1-butylamine and 3-dimethyl-1-isopropylamine.
Examples of polyamines of formula B are: 2-aminopyridine and
aminopyrazine. Examples of polyamines of formula C are:
N-(3-aminopropyl) morpholine, N-(3-aminopropyl) imidazole and
N-(2-aminoethyl) pyrrolidine. Suitable other polyamines are
also identified in U.S. Patents 3,329,658 and 3,449,250. In
the case of formula B those skilled in the art will
appreciate that in some instances one of the bonds on the Xl
and/or the N will be a double bond depending on the nature of
Xl, R4 and/or R5, viz. if X is N or if R4 and/or R5 are
methine radicals.
As indicated hereinabove, the reaction between the
ethylene-alpha-olefin copolymers, such as ethylene-propylene
copolymer, in the presence of a solvent and in the presence
of maleic anhydride and a fxee radical initiator is carried
out at a temperature in the range 80-130C., more or less.
Higher or lower temperatures, however, may be employed, if
desired. Moreover, free radical initiators other than
benzoyl peroxide and dicumylperoxide are also usefully
employed. Similarly, the reaction of the polyamine with
the resulting produced succinic anhydride may also be carried
out at a suitable elevated temperature, such as about 80-130F.,
more or less, as desired. These reactions are carried out to
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fi
completion. The high boiling point, substantially inert or
neutral diluent oil employed in the reactions, particularly to
aid in stripping the aromatic solvent, such as chlorobenzene,
and any excess maleic anhydride or any remaining polyamine from
the reaction mixture, is ad~antageously a petroleum based oil of
lubricating oil quality so that the desired product, the polymer
succinimide, cantained therein in the resulting reaction product
can be readily incorporated as an additive in lubricating oils.
As indicated and demonstrated inert solvents, prefer-
ably inert aromatic solvents, are preferred in the preparation
of the polymer succinimides. Cyclohexanes and other cycloali-
phatic solvents, e.g. cyclopentane and methylcyclohexane are too
reactive. The relatively inert solvents are preferred, such as
the halogenated hydrocarbons, e.g. halogenated aromatic hydro-
carbons, such as chlorobenzene.
It is inaicated hereinabove that the polymer succinimide
in accordance with this invention is incorporated in minor
amounts as an additi~e in petroleum based automotive lubricating
oils, such as an amount in the range 0.05-10% by weight, more
or less. Amounts of the polymer succinimide in the range 0.5-
2.5% by weight up to about 3-4% by weight in lubricating oil
co~positions ~ould be conYentionally employed to impart shear
stability, improved VI and dispersancy to the resulting oil
compositions. As indicated above, the polymer succinimide in-
corporated in lubricating oils as an additive therein has a %
by weight nitrogen content in the range from about 0.02 to about
.0, preferably from about 0.05 to 0.5, more preferably in the
range 0.2-0.3. -
:
_ 16 -
C
. .

11 ~4~9fi
To facilitate the introduction of the copolymer
derivative as an additive into a final lubricating oil blend,
the copolymer derivative as an additive may be prepared as a
concentrate with a solvent, such as a light lubricating oil
having a viscosity of between about 75 and about 300 SUS at
100F.,to form an additive concentrate containing in the
range from about 5 to about 3o%rpreferably about 10-15%,by
weight of the copolymer derivative additive.
As will be apparent to those skilled in the art in
the light of the foregoing disclosure, many alterations,
substitutions and modifications are possible in the practices
of this invention without departing from the spirit or scope
thereof.
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