Lubricating compositions containing synthetic ester base oil, molybdenum compounds and thiadiazole-based compounds

1. A method for imparting anti-wear properties to a high chrome alloy steel, comprising using an effective amount of a lubricating composition on a high chrome alloy steel surface, the lubricating composition comprising a major amount of a grease or synthetic ester base oil and a minor amount of:

(a) a molybdenum compound selected from the group consisting of molybdenum dithiocarbamate, molybdenum dithiophosphate and a mixture thereof; and

(b) one or more anti-wear compound(s) selected from the group consisting of:

(i) a reaction product of:

(A) a thiadiazole dimer having formula (I):

where Z is hydrogen, or an alkyloxy linkage having formula (II):

or combinations thereof, with R 1 being hydrogen, a branched or straight chain C 1 to C 7 alkyl radical, or combinations thereof and R 2 being hydrogen, a branched or straight chain C 1 to C 7 alkyl radical, or combinations thereof, with n being 1 to 2 and t being 0 or 1; and

(B) a poly(ether)glycol having formula (III):

where F is a hydroxyl radical, a branched or straight chain C 1 to C 20 alkoxyl radical, a branched or straight chain C 1 to C 20 alkylcarboxyl radical, a mono-substituted, disubstituted, or tri-substituted glycerol residue, hydrogen, or combinations thereof; where R 3 is hydrogen, a methyl radical, or combinations thereof; where R 4 is hydrogen, a branched or straight chain C 1 to C 20 alkyl radical, a phenyl radical, a C 1 to C 8 branched or straight chain alkyl-substituted-phenyl radical, a C 1 to C 20 branched or straight chain acyl radical, or combinations thereof; and with q being 1 to 300;

(ii) a reaction product of:

(A) a thiadiazole dimer having formula (VI):

where d is 1 to 5 and Z is hydrogen, an alkyloxy linkage having formula (II):

or combinations thereof, with R 1 being hydrogen, a branched or straight chain C 1 to C 7 alkyl radical, or combinations thereof and R 2 being hydrogen, a branched or straight chain C 1 to C 7 alkyl radical, or combinations thereof, wherein t is 0 or 1; and

(B) a poly(ether)glycol having formula (III):

where F is a hydroxyl radical, a branched or straight chain C 1 to C 20 alkoxyl radical, a branched or straight chain C 1 to C 20 alkylcarboxyl radical, a mono-substituted, disubstituted, or tri-substituted glycerol residue, hydrogen, or combinations thereof; where R 3 is hydrogen, a methyl radical, or combinations thereof; where R 4 is hydrogen, a branched or straight chain C 1 to C 20 alkyl radical, a phenyl radical, a C 1 to C 8 branched or straight chain alkyl-substituted-phenyl radical, a C 1 to C 20 branched or straight chain acyl radical, or combinations thereof; and with q being 1 to 300; and

(iii) a mono or dimercapto-1,3,4-thiadiazole monomer which has the structure of formula (VII):

Where R5 is mercaptan, —SH or hydrogen, —H, wherein the weight ratio of the molybdenum compound (a) to the anti-wear compound/compounds (b) is about 1:10 to about 10:1.

2. The method of claim 1 , wherein the weight ratio of the molybdenum compound to the anti-wear compound is about 1:4 to about 4:1.

3. The method of claim 2 , wherein the weight ratio of the molybdenum compound to the anti-wear compound is about 1:2 to about 1:1.

4. The method of claim 1 , wherein the anti-wear compound is (i).

5. The method of claim 4 , wherein the reaction product comprises of one or both of a compound of formula (IV):

or a compound of formula (V)

wherein in is 1 to 50.

6. The method of claim 1 , wherein the anti-wear compound is (ii).

7. The method of claim 1 , wherein the anti-wear compound is (iii).

8. The method of claim 1 , wherein the molybdenum compound is molybdenum dithiocarbamate.

9. The method of claim 8 , wherein the molybdenum dithiocarbamate is molybdenum dialkylthiocarbamate.

10. The method of claim 1 , wherein the molybdenum compound is molybdenum dithiophosphate.

11. The method of claim 2 , wherein the molybdenum dithiophosphate is molybdenum di(2ethylhexyl)phosphorodithioate.

12. The method according to claim 1 , wherein the steel is 440C stainless steel.

13. In combination, a high chrome alloy and a lubricating composition comprised of a major amount of a grease or synthetic ester base oil and a minor amount of:

(a) a molybdenum compound selected from the group consisting of molybdenum dithiocarbamate, molybdenum dithiophosphate and a mixture thereof; and

(b) one or more anti-wear compound(s) selected from the group consisting of:

(i) a reaction product of:

(A) a thiadiazole dimer having formula (I):

where Z is hydrogen, or an alkyloxy linkage having formula (II):

or combinations thereof, with R 1 being hydrogen, a branched or straight chain C 1 to C 7 alkyl radical, or combinations thereof and R 2 being hydrogen, a branched or straight chain C 1 to C 7 alkyl radical, or combinations thereof, with it being 1 to 2 and being 0 or 1; and

(B) a poly(ether)glycol having formula (III):

where F is a hydroxyl radical, a branched or straight chain C 1 to C 20 alkoxyl radical, a branched or straight chain C 1 to C 20 alkylcarboxyl radical, a mono-substituted, disubstituted, or tri-substituted glycerol residue, hydrogen, or combinations thereof; where R 3 is hydrogen, a methyl radical, or combinations thereof; where R 4 is hydrogen, a branched or straight chain C 1 to C 20 alkyl radical, a phenyl radical, a C 1 to C 8 branched or straight chain alkyl-substituted-phenyl radical, a C 1 to C 20 branched or straight chain acyl radical, or combinations thereof; and with q being 1 to 300;

(ii) a reaction product of:

(A) a thiadiazole dimer having formula (VI):

where d is 1 to 5 and Z is hydrogen, an alkyloxy linkage having formula (II):

or combinations thereof, with R 1 being hydrogen, a branched or straight chain C 1 to C 7 alkyl radical, or combinations thereof and R 2 being hydrogen, a branched or straight chain C 1 to C 7 alkyl radical, or combinations thereof, wherein t is 0 or 1; and

(B) a poly(ether)glycol having formula (III):

where F is a hydroxyl radical, a branched or straight chain C 1 to C 20 alkoxyl radical, a branched or straight chain C 1 to C 20 alkylcarboxyl radical, a mono-substituted, disubstituted, or tri-substituted glycerol residue, hydrogen, or combinations thereof; where R 3 is hydrogen, a methyl radical, or combinations thereof; where R 4 is hydrogen, a branched or straight chain C 1 to C 20 alkyl radical, a phenyl radical, a C 1 to C 8 branched or straight chain alkyl-substituted-phenyl radical, a C 1 to C 20 branched or straight chain acyl radical, or combinations thereof; and with q being 1 to 300; and

(iii) a mono or dimercapto-1,3,4-thiadiazole monomer which has the structure of formula (VII):

Where R5 is mercaptan —SH or hydrogen, —H, wherein the weight ratio of the molybdenum compound (a) to the anti-wear compound/compounds (b) is about 1:10 to about 10:1.

14. The combination of claim 13 , wherein the weight ratio of the molybdenum compound to the anti-wear compound is about 1:4 to about 4:1.

15. The combination of claim 14 , wherein the weight ratio of the molybdenum compound to the anti-wear compound is about 1:2 to about 1:1.

16. The combination of claim 13 , wherein the anti-wear compound is (i).

17. The combination of claim 16 , wherein the reaction product comprises of one or both of a compound of formula (IV):

or a compound of formula (V)

wherein m is 1 to 50.

18. The combination of claim 13 , wherein the anti-wear compound is (ii).

19. The combination of claim 13 , wherein the anti-wear compound is (iii).

20. The combination of claim 13 , wherein the molybdenum compound is molybdenum dithiocarbamate.

21. The combination of claim 20 , wherein the molybdenum dithiocarbamate is molybdenum dialkylthiocarbamate.

22. The combination of claim 13 , wherein the molybdenum compound is molybdenum dithiophosphate.

23. The combination of claim 14 , wherein the molybdenum dithiophosphate is molybdenum di(2-ethylhexyl)phosphorodithioate.