US5070131A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gear oil viscosity index improvers
Assignee: Shell USA Inc
•
Filing: 1990-09-28
•
Granted: 1991-12-03
•
Expires: 2010-09-28
Abstract
Abstract A gear oil composition is provided, the composition comprising a hydrogenated star conjugated diolefin polymer having arms with weight average molecular weights between about 3,000 and about 15,000. Such star polymers are effective as viscosity index improvers, and yet are sufficiently shear stable for service in gear oil lubricants.
Inventors
- 👤 Robert B. Rhodes
- 👤 Rudolf J. Eckert
- 👤 Donald E. Loeffler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:44
CPC Classifications
C; C10; C10M; C10M143/00; C10M143/12; C10M7/00; C10M143/10; C10M2205/00; C10M2205/04; C10M2205/06
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
56 words
A gear oil composition having improved shear stability index essentially consisting of gear oil, a viscosity index improver comprising a hydrogenated star polymer comprising at least four arms, the arms comprising, before hydrogenation, polymerized conjugated diolefin monomer units and the arms having a number average molecular weight within the range of about 3,000 to about 15,000.
Claim 2
Dependent Claim
56 words
A gear oil composition having improved shear stability index essentially consisting of gear oil, a viscosity index improver comprising a hydrogenated star polymer comprising at least four arms, the arms comprising, before hydrogenation, polymerized conjugated diolefin monomer units and the arms having a number average molecular weight within the range of about 3,000 to about 15,000.
Claim 3
Dependent Claim
13 words
The gear oil composition of claim 1 wherein the conjugated diolefin is butadiene.
Claim 4
Dependent Claim
13 words
The gear oil composition of claim 1 wherein the conjugated diolefin is isoprene.
Claim 5
Dependent Claim
18 words
The gear oil composition of claim 1 wherein the conjugated diolefin is a combination of isoprene and butadiene.
Claim 6
Dependent Claim
25 words
The gear oil composition of claim 1 wherein the arms have a weight average molecular weight within the range of about 5,000 to about 12,000.
Claim 7
Dependent Claim
20 words
The gear oil composition of claim 1 wherein the star polymer has a shear stability index of 25% or less.
Claim 8
Dependent Claim
19 words
The gear oil composition of claim 1 wherein the star polymer arms are coupled with a polyalkenyl coupling agent.
Claim 9
Dependent Claim
15 words
The gear oil composition of claim 7 wherein the polyalkenyl coupling agent is divinyl benzene.
Claim 10
Dependent Claim
24 words
The gear oil composition of claim 1 wherein the composition comprises from about 0.15 to about 20 percent by weight of hydrogenated star polymer.
Claim 11
Dependent Claim
24 words
The gear oil composition of claim 1 wherein the composition comprises from about 0.5 to about 10 percent by weight of hydrogenated star polymer.
Claim 12
Dependent Claim
26 words
The gear oil composition of claim 1 further comprising one or more components selected from the group consisting of antioxidants, pour point depressants, dyes and detergents.
Claim 13
Dependent Claim
17 words
The gear oil composition of claim 1 wherein the gear oil composition is a multigrade gear oil.
Claim 14
Dependent Claim
37 words
The composition of claim 1 wherein at least on the average of one arm of the hydrogenated star polymer is a arm having at least one hydrogenated conjugated diolefin block and at least one monoalkenyl arene block.
Claim 15
Dependent Claim
23 words
The composition of claim 13 wherein a monoalkenyl arene block is an inside block and hydrogenated conjugated diolefin block is an outer block.
Claim 16
Dependent Claim
14 words
The composition of claim 14 wherein essentially all of the arms are diblock arms.
Claim 17
Dependent Claim
22 words
The gear oil composition of claim 5 wherein the star polymer is one having a shear stability index of 25% or less.
Claim 18
Dependent Claim
19 words
The gear oil composition of claim 16 wherein the star polymer arms are coupled with a polyalkenyl coupling agent.
Claim 19
Dependent Claim
15 words
The gear oil composition of claim 17 wherein the polyalkenyl coupling agent is divinyl benzene.
Claim 20
Dependent Claim
23 words
The gear oil composition of claim 18 wherein the composition comprises from about 0.5 to about 10 percent by weight of star polymer.
Claim 21
Dependent Claim
29 words
The gear oil composition of claim 19 wherein the arms of the star polymer have a number average molecular weight within the range of about 5,000 to about 12,000.
Claim 22
Dependent Claim
13 words
The gear oil composition of claim 20 wherein the conjugated diolefin is isoprene.
Claim 23
Dependent Claim
25 words
The gear oil composition of claim 20 wherein the conjugated diolefin is butadiene and the butadiene is polymerized with 55 percent or more 1,2 addition.
Claim 24
Dependent Claim
18 words
The gear oil composition of claim 20 wherein the conjugated diolefin is a combination of butadiene and isoprene.
Claim 25
Independent Claim
70 words
A method to prepare a multigrade gear oil composition comprising the step of incorporating into the gear oil composition from about 1 to about 15 parts by weight, based on 100 parts by weight gear oil composition of a hydrogenated radial polymer comprising at least four arms comprising, before hydrogenation, polymerized conjugated diolefins, the arms having a weight average molecular weight within the range of about 5,000 to about 15,000.
Claim 26
Independent Claim
70 words
A method to prepare a multigrade gear oil composition comprising the step of incorporating into the gear oil composition from about 1 to about 15 parts by weight, based on 100 parts by weight gear oil composition of a hydrogenated radial polymer comprising at least four arms comprising, before hydrogenation, polymerized conjugated diolefins, the arms having a weight average molecular weight within the range of about 5,000 to about 15,000.
Claim 27
Dependent Claim
23 words
The method of claim 24 wherein the arms have a weight average molecular weight within the range of about 5,000 to about 12,000.
Claim 28
Dependent Claim
19 words
The method of claim 24 wherein the star polymer has a shear stability index of about 25% or less.
Claim 29
Dependent Claim
11 words
The method of claim 24 wherein the conjugated diolefin is isoprene.
Claim 30
Dependent Claim
23 words
The method of claim 24 wherein the conjugated diolefin is butadiene and the butadiene is polymerized with 55 percent or more 1,2 addition.
Claim 31
Dependent Claim
16 words
The method of claim 24 wherein the conjugated diolefin is a combination of isoprene and butadiene.
Claim 32
Dependent Claim
17 words
The method of claim 24 wherein the star polymer arms are coupled with a polyalkenyl coupling agent.
Claim 33
Dependent Claim
13 words
The method of claim 30 wherein the polyalkenyl coupling agent is divinyl benzene.
Claim 34
Dependent Claim
19 words
The method of claim 30 wherein the star polymer has a shear stability index of about 25% or less.
Claim 35
Dependent Claim
11 words
The method of claim 32 wherein the conjugated diolefin is isoprene.
Claim 36
Dependent Claim
22 words
The method of claim 32 wherein the conjugated diolefin is butadiene which has been polymerized with 55 percent or more 1,2 addition.
References Cited (Backward Citations)
US4116917A
Cited
US4156673A
Cited
US4082680A
Cited
US4077893A
Cited
US4141847A
Cited
US4358565A
Cited
US4427834A
Cited
US4490267A
Cited
US4942210A
Cited
US4788361A
Cited
US4970254A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-12-02 | 1995-06-03 | 1995-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-02 | 1999-06-03 | 1999-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-02 | 2003-06-03 | 2003-12-03 | $7700.00 | Window Closed / Lapsed |