Polyolefin-derived dispersants
Ethylene-C 3 -C 10 alpha olefin copolymers, dispersants and lubricating oils/fuel compositions incorporating dispersants, and related methods are generally described herein. The copolymer may comprise ethylene-derived units and C 3 -C 10 alpha-olefin-derived units. The C 3 -C 10 alpha-olefin-derived units may have a carbon number from three to ten. For example, the C 3 -C 10 alpha-olefin-derived units may be propylene-derived units.
1. A dispersant prepared by a process comprising: functionalizing a copolymer derived from ethylene and propylene,
wherein the copolymer has a number average molecular weight of less than 4,000 g/mol as measured by GPC;
wherein at least 30% and less than 65% of the total number of units in the copolymer are ethylene-derived units;
wherein 70 mol % or greater of the copolymer has a carbon-carbon double bond in a terminal monomer unit, and at least 70 mol % of the terminal monomer units that have a carbon-carbon double bond have a terminal group selected from a vinylidene group and a tri-substituted isomer of a vinylidene group, wherein the vinylidene group and the tri-substituted isomer of a vinylidene group of the copolymer have one or more of the following structural formulas (A)-(B):
wherein R represents a methyl group and
indicates a bond attached to the remaining portion of the copolymer;
wherein the copolymer has an average ethylene-derived unit run length n c2 , as determined by 13 C NMR spectroscopy, of less than 2.6, the average ethylene-derived unit run length n c2 is defined as the total number of ethylene-derived units in the copolymer divided by a number of runs of one or more sequential ethylene-derived units in the copolymer, and the average ethylene-derived unit run length n c2 also satisfies the relationship shown by the expression below:
n
C
2
<
(
EEE
+
EEA
+
AEA
)
(
AEA
+
0.5
EEA
)
wherein:
EEE=(x C2 ) 3 ,
EEA=2(x C2 ) 2 (1−x C2 ),
AEA=x C2 (1−x C2 ) 2 ,
x C2 being the mole fraction of ethylene incorporated in the copolymer as measured by 1 H-NMR spectroscopy, E representing an ethylene unit, and A representing a propylene unit, and
wherein the copolymer has a crossover temperature of −25° C. or lower.
2. The dispersant of claim 1 , wherein the copolymer has a crossover temperature of −35° C. or lower.
3. The dispersant of claim 1 , wherein at least 30% and less than 60% of the total number of units in the copolymer are ethylene-derived units.
4. The dispersant of claim 1 , wherein at least 30% and less than 50% of the total number of units in the copolymer are ethylene-derived units.
5. The dispersant of claim 1 , wherein at least 85 mol % of the unsaturation is the terminal vinylidene group and the terminal tri-substituted isomer of a vinylidene group.
6. The dispersant of claim 1 , wherein at least 95 mol % of the unsaturation is the terminal vinylidene group and the terminal tri-substituted isomer of a vinylidene group.
7. The dispersant of claim 1 , wherein the copolymer has an average ethylene run length of less than 2.4.
8. The dispersant of claim 1 , wherein the copolymer has an average ethylene run length of less than 2.2.
9. The dispersant of claim 1 , wherein the copolymer has a polydispersity index of less than or equal to 4.
10. The dispersant of claim 1 , wherein the copolymer has a polydispersity index of less than or equal to 3.
11. The dispersant of claim 1 , wherein the ethylene content is 40-60 mol % and the propylene content is 40-60 mol %.
12. The dispersant of claim 1 , wherein the ethylene content is about 40-50 mol % and the propylene content is about 50-60 mol %.
13. The dispersant of claim 1 , wherein the number average molecular weight of the copolymer is less than 2,500 g/mol, as measured by GPC.
14. The dispersant of claim 1 , wherein the number average molecular weight of the copolymer is less than 1,500 g/mol, as measured by GPC.
15. The dispersant of claim 1 , wherein the dispersant is post-treated.
16. The dispersant of claim 1 , wherein the dispersant is posted treated with anhydride, a boron compound, or a mixture thereof.
17. The dispersant of claim 1 , wherein the dispersant has one of the following formulas:
wherein R 1 is an hydrocarbyl radical derived from the copolymer; R 2 is a divalent C 1 -C 6 alkylene; R 3 is a divalent C 1 -C 6 alkylene; each of R 4 and R 5 , independently, is H, C 1 -C 6 alkyl,
or, together with the N to which they are attached to, form a 5 or 6-membered ring optionally fused with an aromatic or non-aromatic ring; R 6 is H or C 1 -C 6 alkyl, or —CH 2 —(NH—R 2 ) n —NR 4 R 5 ; Y is a covalent bond or C(O); and n is 0, 1, 2, 3, 4, 5, 6, 7, or 8.
18. A lubricating oil, comprising:
at least 50 wt % of a base oil;
3-20 wt % of a viscosity index improver;
0-1 wt % of a pour point depressant; and
0.2-20 wt % of the dispersant of claim 1 .
19. The lubricating oil of claim 18 , wherein the lubricating oil has a mini-rotary viscometer (MRV) value of 60,000 cP or less at −30° C. as determined by the ASTM D4684 test.
20. The lubricating oil of claim 18 , wherein the lubricating oil has a mini-rotary viscometer (MRV) value of 60,000 cP or less at −40° C. as determined by the ASTM D4684 test.
21. The lubricating oil of claim 18 , wherein the lubricating oil contains less than 10 wt % of the dispersant.
22. A lubricating additive package comprising:
30-80 wt % of the dispersant of claim 1 .
23. A fuel composition or fuel additive composition, comprising the dispersant of claim 17 .
24. The fuel composition or fuel additive composition of claim 23 , the dispersant having one of the following formulas:
wherein R 1 is an hydrocarbyl radical derived from the copolymer; R 2 is a divalent C 1 -C 6 alkylene; R 3 is a divalent C 1 -C 6 alkylene; each of R 4 and R 5 , independently, is H, C 1 -C 6 alkyl,
or, together with the N to which they are attached to, form a 5 or 6-membered ring optionally fused with an aromatic or non-aromatic ring; R 6 is H or C 1 -C 6 alkyl, or —CH 2 —(NH—R 2 ) n —NR 4 R 5 ; Y is a covalent bond or C(O); and n is 0, 1, 2, 3, 4, 5, 6, 7, or 8.