POLYMERS AND LUBRICATING COMPOSITIONS CONTAINING POLYMERS

Abstract

A polymer having the structure (I):

##STR00001##

L is a linking group, R is a hydrocarbon group or a substituted-hydrocarbon group, and x is 2 or more, preferably from 2 to 100, more preferably from 2 to 50. Each {Q} is (a) an identical polymer block composed of 3 or more monomer units, or (b) contains a plurality of polymer blocks, each polymer block being composed of 3 or more monomer units, such that the moiety {Q}-L-{Q} has the structure {P.sub.n . . . P.sub.2P.sub.1}-L-{P.sub.1P.sub.2 . . . P.sub.n} where each P.sub.n is an individual polymer block, the number of polymer blocks n in each {Q} being the same; wherein for each value of n the polymer blocks are identical; and wherein n is an integer of 2 or more, preferably from 2 to 100, more preferably from 2 to 50.

Claims

1. A polymer having the structure (I): ##STR00012## wherein L is a linking group, R is a hydrocarbon group or a substituted-hydrocarbon group, and x is 2 or more; and wherein each {Q} is (a) an identical polymer block composed of 3 or more monomer units, or (b) contains a plurality of polymer blocks, each polymer block being composed of 3 or more monomer units, such that the moiety {Q}-L-{Q} has the structure {P.sub.n . . . P.sub.2P.sub.1}-L-{P.sub.1P.sub.2 . . . P.sub.n} where each P.sub.n is an individual polymer block, the number of polymer blocks n in each {Q} being the same; wherein for each value of n the polymer blocks are identical; and wherein n is an integer of 2 or more.

2. A polymer according to claim 1, wherein each polymer block has the structure (II): ##STR00013## wherein m is an integer of at least 3; wherein R.sub.1 is hydrogen or methyl; wherein X is a hydrocarbon group having from 1 to 50 carbon atoms, a substituted-hydrocarbon group having from 1 to 50 carbon atoms, COOR.sub.2, COSR.sub.2 or CONR.sub.2R.sub.3, OCOR.sub.2, CONHR.sub.2, CN, COSiR.sub.2R.sub.3R.sub.4 or Cl wherein R.sub.2, R.sub.3 and R.sub.4 are independently hydrogen, a hydrocarbon group having from 1 to 50 carbon atoms, or a substituted-hydrocarbon group having from 1 to 50 carbon atoms; and wherein in each block having structure (II), each R.sub.1 and each X and each m may be the same or different.

3. A polymer according to claim 2, wherein each X is COOR.sub.2, where each R.sub.2 is a straight-chain or branched alkyl group.

4. A polymer according to claim 2, wherein each X is COOR.sub.2, where each R.sub.2 is a polyalkylene glycol residue of the formula [(CR.sub.5H).sub.yO].sub.zOR.sub.6 where y is an integer from 2 to 4, and z is from 2 to 100, R.sub.5 is hydrogen or an alkyl, and .sub.6 is hydrogen, an alkyl group or an aryl group.

5. A polymer according to claim 2, wherein each {Q} is composed of a plurality of copolymer blocks of structure (II) such that the moiety {Q}-L-{Q} has the structure (III): ##STR00014## wherein each m.sub.1, m.sub.2 . . . m.sub.n is independently an integer of at least 3 and wherein each X.sub.1, X.sub.2 . . . X.sub.n is independently a hydrocarbon group having from 1 to 50 carbon atoms, a substituted-hydrocarbon group having from 1 to 50 carbon atoms, COOR.sub.2, COSR.sub.2 or CONR.sub.2R.sub.3, OCOR.sub.2, CONHR.sub.2, CN, COSiR.sub.2R.sub.3R.sub.4 or Cl wherein R.sub.2, R.sub.3 and R.sub.4 are independently hydrogen, a hydrocarbon group having from 1 to 50 carbon atoms, or a substituted-hydrocarbon group having from 1 to 50 carbon atoms

6. A polymer according to claim 5, wherein each X.sub.1, X.sub.2 . . . X.sub.n is COOR.sub.2, where in each instance n, R.sub.2 is a straight-chain or branched alkyl group.

7. A polymer according to claim 5, wherein each X.sub.1, X.sub.2 . . . X.sub.n is COOR.sub.2, where in each instance n, each R.sub.2 is a polyalkylene glycol residue of the formula [(CR.sub.5H).sub.yO].sub.zOR.sub.6 where y is an integer from 2 to 4, and z is from 2 to 100, R.sub.5 is hydrogen or an alkyl group, and R.sub.6 is hydrogen, an alkyl group or an aryl group.

8. A polymer according to claim 5, wherein each X.sub.1, X.sub.2 . . . X.sub.n is COOR.sub.2 and n is at least 2; wherein in at least one instance n, R.sub.2 is a straight-chain or branched alkyl group; and wherein in at least one other instance n, R.sub.2 is a polyalkylene glycol residue of the formula [(CR.sub.5H).sub.yO].sub.zOR.sub.6 where y is an integer from 2 to 4, and z is from 2 to 100, R.sub.5 is hydrogen or an alkyl group, and R.sub.6 is hydrogen, an alkyl group or an aryl group.

9. A polymer according to claim 2, wherein each R.sub.1 is hydrogen.

10. A polymer according to claim 5, wherein each X.sub.1, X.sub.2 . . . X.sub.n is COOR.sub.2 and n is 2; wherein in one instance n, R.sub.2 is a branched alkyl group and in the other instance n, R.sub.2 is a polyalkylene glycol residue of the formula [(CR.sub.5H).sub.yO].sub.zOR.sub.6 where y is an integer from 2 to 4, and z is from 2 to 100, R.sub.5 is hydrogen or an alkyl group, and R.sub.6 is hydrogen, an alkyl group or an aryl group.

11. A polymer according to claim 10, wherein the branched alkyl group is 2-ethylhexyl, and the polyalkylene glycol residue is of the formula [(CH.sub.2).sub.yO].sub.zOMe where y is 2.

12. A polymer according to claim 11, wherein the branched alkyl group is 2-ethylhexyl, and the polyalkylene glycol residue is of the formula [(CH.sub.2).sub.yO].sub.zOMe where y is 2 and z is an average value of 7 to 8.

13. A polymer according to claim 5, wherein each X.sub.1, X.sub.2 . . . X.sub.n is COOR.sub.2 and n is 3; wherein in one instance n, R.sub.2 is a branched alkyl group and in the other two instances n, R.sub.2 is a polyalkylene glycol residue of the formula [(CR.sub.5H).sub.yO].sub.zOR.sub.6 where y is an integer from 2 to 4, and z is from 2 to 100, R.sub.5 is hydrogen or an alkyl group, and R.sub.6 is hydrogen, an alkyl group or an aryl group.

14. A polymer according to claim 13, wherein the branched alkyl group is 2-ethylhexyl, and each polyalkylene glycol residue is the same and of the formula [(CH.sub.2).sub.yO].sub.zOMe where y is 2.

15. A polymer according to claim 14, wherein the branched alkyl group is 2-ethylhexyl, and each polyalkylene glycol residue is the same and of the formula [(CH.sub.2).sub.yO].sub.zOMe where y is 2 and z is an average value of 7 to 8.

16. A polymer according to claim 1, wherein L is the residue of a di-functional initiator molecule which is effective to initiate polymerisation of the monomers used to form the polymer blocks.

17. A polymer according to claim 1, wherein L has the structure: ##STR00015## where * indicates the points of attachment to the remainder of the polymer, and where a is an integer from 1 to 100.

18. A polymer according to claim 1, wherein R has the structure: ##STR00016## where * indicates the points of attachment to the remainder of the polymer.

19. A lubricating composition comprising a major amount of a base lubricant, and a minor amount of a polymer according to claim 1.

20. A lubricating oil composition comprising a major amount of an oil of lubricating viscosity, a minor amount of a polymer according to claim 1, and a minor amount of one or more of a phosphorus-containining compound, and oxidation inhibitor, a dispersant, a metal detergent, and anti-wear agent, a friction modifier and a viscosity modifier.

21. A method of reducing the friction between contacting surfaces of a mechanical device, the method comprising lubricating the surfaces with a lubricating composition according to claim 19.

22. A method of reducing the friction between contacting surfaces of a mechanical device, the method comprising lubricating the surfaces with a lubricating oil composition according to claim 20.

23. The method according to claim 22, wherein the mechanical device is a spark-ignited or compression ignited internal combustion engine.

Description

EXAMPLES

[0119] Synthesis of Polyacrylate Polymers According to the Invention

[0120] The Table below details polymers according to the present invention. All were made by the method described below using the reactants listed in the Table. Examples 1 and 2 employed Stages 1, 2 and 3 whereas Example 3 omitted Stage 2 as only one monomer was used. With reference to the first aspect of the present invention, Example 3 is a polymer according to embodiment (a), i.e. where each {Q} is an identical polymer block; and Examples 1 and 2 are polymers according to embodiment (b), i.e. where each {Q} contains a plurality of polymer blocks.

[0121] Stage 1

[0122] Monomer 1, ethylene glycol-derived bisinitiator [see below *] (1.00 equiv.), tris(2-dimethylaminoethyl)amine (Me.sub.6TREN) (0.36 equiv.), CuBr.sub.2 (0.10 equiv.) and DMSO (50% v/v) were charged to a Schlenk tube and sealed with a rubber septum. After degassing the reaction mixture for 30 minutes, a stirring bar wrapped with pre-activated copper wire (5 cm) was added to the reaction mixture in a counter-current of nitrogen. The tube was sealed again and the reaction mixture stirred at 25 C. until full conversion was observed (between 4 and 12 hours). Conversion was measured by 1H NMR spectroscopy and SEC analysis was carried out with samples diluted in THF which were filtered over basic alumina prior to analysis to remove residual copper species.

[0123] Stage 2

[0124] Monomer 2 in DMSO (50% v/v) and another portion of tris(2-dimethylaminoethyl)amine (Me.sub.6TREN) (0.36 equiv.) and CuBr.sub.2 (0.10 equiv.) were added into a glass vial and degassed for 30 minutes before transferring to the reaction mixture from Stage 1. The tube was sealed again and the reaction mixture stirred at 25 C. until full conversion was observed.

[0125] Stage 3

[0126] After full monomer conversion, a solution of bisthiol (1.00 equiv.) and triethylamine in DMF was added at ambient temperature to the reaction mixture. The mixture was then stirred overnight at room temperature before SEC analysis was carried out. The crude product was purified by filtration over basic alumina followed by precipitation from cold methanol to provide the pure polymer as a yellowish oil. The polymer obtained was characterised by 1H NMR and GPC with RI and SUV detectors.

[0127] The structures of the polymers obtained are given below the Table. [0128] In each case, the ethylene glycol derived bisinitiator was the following compound:

##STR00010##

TABLE-US-00003 Mn Monomer 1 Monomer 2 bisthiol (g/mol) Example 1 PEG EH 4,4-thiodiben- 55900 2.42 zenethiol Example 2 PEG EH 4,4-thiodiben- 74800 2.57 zenethiol Example 3 EH 1,3,4-thiadia- 15800 1.92 zole-2,5-dithiol PEG: polyethylene glycol acrylate (Mn of polyethylene glycol group = 480 g/mol) EH: 2-ethylhexyl acrylate

##STR00011##

Friction Measurements for Lubricating Oils Containing Polymers According to the Invention.

[0129] Each of the polymers of Examples 1, 2 and 3 were added to a Group I base oil in an amount of 1% by weight, based on the weight of the oil. The traction coefficient was measured using an MTM bench test at an oil temperature of 135 C. and a rolling speed of 20 mm/second. Results are given in the table below together with the result of an experiment run using the base oil alone.

TABLE-US-00004 Polymer Traction coefficient None (base oil only) 0.0804 Example 1 0.0348 Example 2 0.0370 Example 3 0.0362

[0130] It is clear from the results that the polymers of the invention provided a significant decrease in traction coefficient compared to the base oil alone. This reduction in friction indicates that there was less contact between the metal surfaces during the test such that the oils containing the polymers may be expected to provide wear protection to the surfaces of a machine lubricated by the oils, for example in an engine.