Friction reducing additive

Abstract

An automotive engine oil and/or fuel comprising a base stock and an organic polymeric friction reducing additive is claimed. A method of reducing friction in an automotive engine oil and/or fuel by the addition of the organic polymeric friction reducing additive to the base stock is also claimed.

Claims

1. A non-aqueous automotive engine oil formulation, comprising a base stock, an organic polymeric friction reducing additive, a viscosity index improver, and an additive selected from organo-sulphur compounds and organo-molybdenum compounds, wherein the friction reducing additive has a molecular weight ranging from 1000 to 30,000 Daltons and is the reaction product of: a) a hydrophobic polymeric sub unit which comprises a polyolefin derivatized to comprise a diacid and/or anhydride group; b) a hydrophilic polymeric sub unit which comprises a hydrophilic polymer selected from polyethers; and c) at least one of the following: i) at least one backbone moiety capable of linking together polymeric sub units; and ii) a chain terminating group.

2. The automotive engine oil formulation of claim 1, wherein the hydrophobic polymeric sub unit comprises polyisobutylene polymer which has been subjected to maleinisation to form polyisobutylene succinic anhydride having a molecular weight in the range of 300 to 5000 Da.

3. The automotive engine oil formulation of claim 1, wherein the hydrophilic polymeric sub unit comprises a polyethylene glycol.

4. The automotive engine oil formulation of claim 1, wherein the reaction product comprises some block copolymer units formed from linking together during the reaction of some of the hydrophobic and hydrophilic polymeric sub units.

5. The automotive engine oil formulation of claim 4, wherein the number of block copolymer units ranges from 1 to 20.

6. The automotive engine oil formulation of claim 4, wherein the number of block copolymer units ranges from 1 to 15.

7. The automotive engine oil formulation of claim 4, wherein the number of block copolymer units ranges from 1 to 7.

8. The automotive engine oil formulation of claim 1, wherein the base stock has one of a Group II, Group III or Group IV base oil as its major component.

9. The automotive engine oil formulation of claim 1, wherein the friction reducing additive is the reaction product of: a) a hydrophobic polymeric sub unit which comprises a polyolefin derivatized to comprise a diacid and/or anhydride group; b) a hydrophilic polymeric sub unit which comprises a hydrophilic polymer selected from polyethers; and c) at least one backbone moiety capable of linking together polymeric sub units.

10. The automotive engine oil formulation of claim 9, wherein the backbone moiety is chosen from a polyol, a polycarboxylic acid and mixtures thereof.

11. The automotive engine oil formulation of claim 1, wherein the friction reducing additive is the reaction product of: a) a hydrophobic polymeric sub unit which comprises a polyolefin derivatized to comprise a diacid and/or anhydride group; b) a hydrophilic polymeric sub unit which comprises a hydrophilic polymer selected from polyethers; and c) a chain terminating group.

12. The automotive engine oil formulation of claim 11, wherein the chain terminating group is any fatty carboxylic acid.

13. The automotive engine oil formulation of claim 1, wherein the viscosity index improver is selected from the group consisting of polyisobutenes, polymethacrylates acid esters, polyacrylate acid esters, diene polymers, polyalkyl styrenes, alkenyl aryl conjugated diene copolymers, and polyolefins.

14. An automotive engine oil formulation, comprising: a base stock; and an automotive engine oil additive package, wherein the automotive engine oil additive package comprises at least one automotive engine oil additive selected from the group consisting of detergents, dispersants, oxidation inhibitors, corrosion inhibitors, rust inhibitors, anti-wear additives, foam depressants, pour point depressants, viscosity index improvers, and mixtures thereof; wherein the automotive engine oil formulation comprises an organic polymeric friction reducing additive, wherein the friction reducing additive has a molecular weight ranging from 1000 to 30,000 Daltons and is the reaction product of: a) a hydrophobic polymeric sub unit which comprises a polyolefin derivatized to comprise a diacid and/or anhydride group; b) a hydrophilic polymeric sub unit which comprises a hydrophilic polymer selected from polyethers; and c) at least one of the following: i) at least one backbone moiety capable of linking together polymeric sub units; or ii) a chain terminating group.

15. The automotive engine oil formulation according to claim 14 wherein the automotive engine oil additive package comprises a viscosity index improver, a foam depressant, and a pour point depressant.

16. An automotive engine oil formulation, comprising a base stock selected from the group consisting of Group I to Group V base oils, an organic polymeric friction reducing additive, a dispersant and a detergent, wherein the friction reducing additive has a molecular weight ranging from 1000 to 30,000 Daltons and is the reaction product of: a) a hydrophobic polymeric sub unit which comprises a polyolefin derivatized to comprise a diacid and/or anhydride group; b) a hydrophilic polymeric sub unit which comprises a hydrophilic polymer selected from polyethers; and c) at least one of the following: i) at least one backbone moiety capable of linking together polymeric sub units; and ii) a chain terminating group.

17. The automotive engine oil formulation of claim 16 wherein the dispersant is selected from carboxylic dispersants, amine dispersants, Mannich dispersants and polymeric dispersants.

Description

EXAMPLES

Example 1

(1) Organic Polymeric Friction Reducing Additive—Additive A

(2) The hydrophobic polymeric sub unit is a commercially available maleinised polyisobutylene derived from a polyisobutylene of average molecular weight 1000 amu with an approximate degree of maleinisation of 78% and a saponification value of 85 mg KOH/g.

(3) The hydrophilic polymeric sub unit is a commercially available poly (ethyleneoxide), PEG.sub.600, having a hydroxyl value of 190 mg KOH/g.

(4) Additive A

(5) Maleinised polyisobutylene (113.7 g) and glycerol (5.5 g), were charged to a glass round bottomed flask equipped with mechanical stirrer, isomantle heater and overhead condenser and reacted at 100-130 deg C. under nitrogen atmosphere for 4 hrs.

(6) PEG.sub.600 (71.8 g) and esterification catalyst tetrabutyl titanate (0.2 g) were added, and reaction continued at 200-220 deg C. with removal of water and reduced pressure to an acid value<6 mg KOH/g. Adipic acid (8.8 g) was added and reaction continued under the same conditions to acid value<5 mkg KOH/g. The final product polyester, Additive A, was a dark brown liquid with viscosity at 100 deg C. of approximately 3500 cP.

(7) Organic Polymeric Friction Reducing Additive—Additive B

(8) The hydrophobic polymeric sub unit is a commercially available maleinised polyisobutylene derived from a polyisobutylene of average molecular weight 950 amu with an approximate saponification value of 98 mg KOH/g.

(9) The hydrophilic polymeric sub unit is a commercially available poly (ethyleneoxide), PEG.sub.600, having a hydroxyl value of 190 mg KOH/g.

(10) Additive B

(11) Maleinised polyisobutylene, (110 g), PEG.sub.600 (72 g), glycerol (5 g) and tall oil fatty acid (25 g) were charged to a glass round bottomed flask equipped with mechanical stirrer, isomantle heater and overhead condenser and reacted with esterification catalyst tetrabutyl titanate (0.1 g) at 200-220 deg C. with removal of water to final acid value<10 mg KOH/g. The final product polyester, Additive B, was a dark brown, viscous liquid.

(12) Organic Polymeric Friction Reducing Additive—Additive C.

(13) The hydrophobic copolymer reactant is a commercially available maleinised polyisobutylene, derived from a polyisobutylene of average molecular weight 1000 amu, with an approximate saponification value 95 mg KOH/g.

(14) The hydrophilic copolymer reactant was a commercially available poly(ethyleneoxide) (PEG.sub.600) having a hydroxyl value of 190 mg KOH/g.

(15) Additive C

(16) Maleinised polyisobutylene, (100 g), polyethylene oxide (70 g) and tall oil fatty acid (25 g) were charged to a glass round bottomed flask equipped with mechanical stirrer, isomantle heater, overhead condenser and Dean and Stark separator and reacted with entraining solvent xylene (25 g) under reflux with water removal to final acid value<10 mg KOH/g. At end of reaction, residual xylene was stripped off under reduced pressure to give product polyester, Additive C, as a brown viscous liquid.

Example 2

(17) The coefficient of friction of an automotive engine oil comprising 92% GpIV (INEOS Durasyn 166 PAO6) and 8% GpV base stock (Priolube 3970 ester ex Croda)) and further comprising 0.5% organic polymeric friction reducing additive was determined at 100° C. and 150° C. using a Mini Traction Machine with a ¾ inch ball on a smooth disc. The load applied was 36N (1 GPa contact pressure) and the speed of rotation was from 0.01 to 0.05 m/s. The results are illustrated in Table 1 for 100° C. and Table 2 for 150° C.

(18) TABLE-US-00001 TABLE 1 Polymeric No Additive Glycerol Oleylamide friction reducing present Additive A Additive B Monooleate (OLA) Additive Friction Friction Friction (GMO) (comparative) (comparative) Speed (m/s) coeff coeff coeff Friction coeff Friction coeff 0.01 0.088 0.043 0.033 0.070 0.063 0.02 0.080 0.039 0.032 0.060 0.065 0.05 0.078 0.037 0.036 0.048 0.065

(19) TABLE-US-00002 TABLE 2 Polymeric No Additive Glycerol Oleylamide friction reducing present Additive A Additive B Monooleate (OLA) Additive Friction Friction Friction (GMO) (comparative) (comparative) Speed (m/s) coeff coeff coeff Friction coeff Friction coeff 0.01 0.105 0.013 0.050 0.042 0.070 0.02 0.095 0.013 0.050 0.038 0.062 0.05 0.088 0.015 0.048 0.045 0.065

Example 3

(20) Example 2 was repeated at both 100° C. and 150° C. except that the automotive engine oil was replaced by a formulated Gp II 5W-40 HDDEO (Shell Catenex T121 (13%), Catenex T129 (50%) and Catenex T145 (18%) with 6% Pantone 8002 and 13% friction modifier free additive package)

(21) The results are illustrated in Table 3.

(22) TABLE-US-00003 TABLE 3 Polymeric friction Glycerol Glycerol reducing Not Monooleate Not Monooleate Additive present Additive A (comparative) present Additive A (comparative) Temp (° C.) 100 100 100 150 150 150 Speed Friction Friction Friction Friction Friction (m/s) coeff coeff coeff coeff coeff Friction coeff 0.01 0.125 0.074 0.095 0.135 0.110 0.121 0.02 0.114 0.068 0.087 0.134 0.114 0.121 0.05 0.057 0.042 0.042 0.109 0.089 0.087

Example 4

(23) Example 2 was repeated at both 100° C. and 150° C. except that the automotive engine oil was replaced by a Gp II mineral oil (Shell Catenex 1129) The results are illustrated in Table 4.

(24) TABLE-US-00004 TABLE 4 Polymeric friction Glycerol Glycerol reducing Not Monooleate Not Monooleate Additive present Additive A (comparative) present Additive A (comparative) Temp (° C.) 100 100 100 150 150 150 Speed Friction Friction Friction Friction Friction (m/s) coeff coeff coeff coeff coeff Friction coeff 0.01 0.102 0.052 0.09 0.091 0.023 0.090 0.02 0.092 0.05 0.08 0.085 0.021 0.078 0.05 0.084 0.052 0.069 0.077 0.022 0.076

(25) It is clear from the data in Examples 2, 3 and 4 that polymeric friction reducing additives of the present invention are effective friction modifiers for automotive engine oils and are superior to current commercially available products.

Example 5

(26) Film thickness was measured, using the principle of optical interferometry on a PCS instruments ultra film thin film rig with a silica coated glass disc positioned above a loaded ball for 0.5% by weight of the polymeric friction reducing additive of the invention, Additive A, in the automotive engine oil of Example 2. The film thickness in nm was measured at a temperature of 60° C. with a load pressure of 20N at a speed of 0.004 m/s to 5 m/s. The results are recorded in Table 5.

(27) TABLE-US-00005 TABLE 5 Film thickness Flim thickness (nm) - no (nm) - Speed (m/s) Additive Speed (m/s) Additive A 4.602 252.4 4.364 254.6 0.852 85.3 1.133 109.5 0.610 67.6 0.809 87.0 0.312 33.5 0.413 47.8 0.016 4.8 0.015 10.3 0.012 4.4 0.008 9.1 0.006 2.3 0.006 8.1 0.004 2.0 0.004 6.8

(28) The above data illustrates the ability of an organic polymeric friction reducing additive of the invention to form a thick film at low speeds.

Example 6

(29) The oxidative stability of organic polymeric friction reducing additive of the invention in was measured at 100° C. over 164 hours according to IP307. The initial acid value, acid value after oxidation and acid value of volatiles in distilled water after oxidation were measured and the change in acid value calculated. The results are shown in Table 6.

(30) TABLE-US-00006 TABLE 6 Acid Total Change Acid value of Acid in acid Initial value volatiles Value value due to Acid after in distilled after oxidation Additive Value oxidation water oxidation process Additive A 3.3 1.3 4.6 5.9 2.6 Additive B 6.6 3.5 5.4 8.9 2.3 GMO 0.1 4.0 1.6 5.6 5.5 (comparative)

(31) The results show that organic polymeric friction reducing additives of the invention have a far greater oxidative stability than current commercial products.

Example 7

(32) Compatibility of 0.5% of organic polymeric friction reducing additive of the invention in both GpII (Catenex T129 ex Shell) and GpIV (Durasyn 166 ex INEOS) base stocks was measured at 23 and 4° C. The results are shown in Table 7.

(33) TABLE-US-00007 TABLE 7 Temp Gp II base stock Gp IV base stock in Additive GMO (com- OLA Additive GMO OLA ° C. A parative) (comp.) A (comp.) (comp.) 23 Yes Yes No Yes Yes No 4 Yes No No Yes No No

(34) In both cases Additive A was found to be compatible with the base stocks at both temperatures which compares favourably with the current commercial products.

Example 8

(35) Emulsion retention of 1% of the organic polymeric friction reducing additive of the invention was measured in a Gp II (Catenex T129) and Gp III (Shell XHVI 5.2) mineral oil according to the proposed GF-5 emulsion retention test. In each case 185 ml of mineral oil with additive, 18.5 ml of E85 and 18.5 ml of distilled water were blended using a Waring blender for 1 minute at room temperature. Each blend was then stored at both room temperature and 0° C. for 24 hours and the separation assessed. The results are recorded in Tables 8 and 9 below for room temperature and 0° C. respectively.

(36) TABLE-US-00008 TABLE 8 Oil Emulsion Water Pass/ Additive Mineral Oil (%) (%) (%) Fail None Catenex 129 Additive A Catenex 129 0 100 0 Pass GMO Catenex 129 1 85 14 Fail (comparative) None Shell XHVI 5.2 Additive A Shell XHVI 5.2 0 100 0 Pass GMO Shell XHVI 5.2 1 85 14 Fail (comparative)

(37) TABLE-US-00009 TABLE 9 Oil Emulsion Water Pass/ Additive Mineral Oil (%) (%) (%) Fail None Catenex 129 Additive A Catenex 129 0 100 0 Pass GMO Catenex 129 1 86 13 Fail (comparative) None Shell XHVI 5.2 Additive A Shell XHVI 5.2 0 100 0 Pass GMO Shell XHVI 5.2 1 85 14 Fail (comparative)

(38) The results in Tables 8 and 9 show that the organic polymeric friction modifier is stable at high dose levels of 1% compared to current commercial products.

Example 9

(39) Organic Polymeric Friction Reducing Additive—Additive D

(40) The hydrophobic polymeric sub unit is a maleinised polyisobutylene having approximate molecular weight 550 amu.

(41) The hydrophilic polymeric sub unit is a commercially available poly (ethyleneoxide), PEG.sub.600, having a hydroxyl value of 190 mg KOH/g.

(42) Additive D

(43) Maleinised polyisobutylene, (277 g), PEG.sub.600 (606 g), adipic acid (59 g) and tall oil fatty acid (61 g) were charged to a glass round bottomed flask equipped with mechanical stirrer, isomantle heater and overhead condenser and reacted with esterification catalyst tetrabutyl titanate (0.1 g) at 200-220 deg C. with removal of water to final acid value<10 mg KOH/g. The final product polyester, Additive D, was a dark brown, viscous liquid.

(44) Organic Polymeric Friction Reducing Additive—Additive E

(45) The hydrophobic polymeric sub unit is a maleinised polyisobutylene having approximate molecular weight 1000 amu.

(46) The hydrophilic polymeric sub unit is a commercially available poly (ethyleneoxide), PEG.sub.1000 having a hydroxyl value of 110 mg KOH/g.

(47) Additive E

(48) Maleinised polyisobutylene, (438 g), PEG.sub.1000 (445 g), glycerol (20 g) and tall oil fatty acid (97 g) were charged to a glass round bottomed flask equipped with mechanical stirrer, isomantle heater and overhead condenser and reacted with esterification catalyst tetrabutyl titanate (0.1 g) at 200-220 deg C. with removal of water to final acid value<10 mg KOH/g. The final product polyester, Additive E, was a dark brown, viscous liquid.

Example 10

(49) The coefficient of friction of an automotive engine oil comprising 92% GpIV (INEOS Durasyn 166 PAO6) and 8% GpV base stock (Priolube 3970 ester ex Croda)) and further comprising 0.5% organic polymeric friction reducing additive was determined at 100° C. and 150° C. using a Mini Traction Machine with a ¾ inch ball on a smooth disc. The load applied was 36N (1 GPa contact pressure) and the speed of rotation was from 0.01 to 0.05 m/s. The results are illustrated in Table 10 for 100° C. and Table 11 for 150° C.

(50) TABLE-US-00010 TABLE 10 Polymeric Glycerol Oleylamide friction reducing Not present Additive D Additive E Monooleate (OLA) Additive Friction Friction Friction (GMO) (comparative) (comparative) Speed (m/s) coeff coeff coeff Friction coeff Friction coeff 0.01 0.088 0.010 0.032 0.070 0.063 0.02 0.077 0.012 0.029 0.059 0.065 0.05 0.071 0.024 0.036 0.048 0.063

(51) TABLE-US-00011 TABLE 11 Polymeric Glycerol Oleylamide friction reducing Not present Additive D Additive E Monooleate (OLA) Additive Friction Friction Friction (GMO) (comparative) (comparative) Speed (m/s) coeff coeff coeff Friction coeff Friction coeff 0.01 0.097 0.009 0.010 0.043 0.069 0.02 0.089 0.011 0.014 0.036 0.063 0.05 0.080 0.017 0.023 0.045 0.063