Additive for lubricant compositions comprising an organomolybdenum compound, and a derivatized triazole

Abstract

A lubricating composition for use in heavy duty diesel engines which is formulated to allow the use of organo-molybdenum compounds but which overcomes the issue of Cu and/or Pb corrosion and also maintains elastomer seal compatibility. The lubricant is characterized by having a composition comprising (A) an organo-molybdenum compound, (B) an alkylated diphenylamine derivative of triazole, (C) base oil, and optionally (D) one or more additives selected from the group including antioxidants, dispersants, detergents, anti-wear additives, extreme pressure additives, friction modifiers, rust inhibitors, corrosion inhibitors, seal swell agents, anti-foaming agents, pour point depressants and viscosity index modifiers.

Claims

1. A lubricating composition comprising a major amount of a lubricating base oil, and (A) an organo-molybdenum compound providing a total molybdenum content of about 50 ppm to 800 ppm in the lubricating composition and (B) an alkylated diphenylamine derivative of triazole present in the amount from about 0.01-5.0% by weight of the lubricant composition, wherein (B) excludes derivatized tolutriazoles and derivatized benzotriazoles.

2. The lubricating composition according to claim 1, wherein the total molybdenum content is about 75 ppm to about 350 ppm.

3. The lubricating composition according to claim 1, wherein the organo-molybdenum compound is selected from one or both of a molybdenum dithiocarbamate and a molybdenum ester/amide complex.

4. The lubricating composition according to claim 1, wherein the alkylated diphenylamine derivative of triazole is present in an amount from about 0.05-3.0% by weight of the lubricating composition.

5. The lubricating composition according to claim 1, wherein the ratio of (A):(B) based on molybdenum content (in wt %) to triazole derivative content (in wt %) is from about 0.001:1 to 20:1.

6. The lubricating composition according to claim 1 wherein the alkylated diphenylamine derivative of triazole is selected from one or both of 1-[di-(4-alkylphenyl)aminomethyl]triazole and 1-[di-4-alkylphenyl)(phenyl)aminomethyl]triazole.

7. The lubricating composition according to claim 6 wherein the alkylated diphenylamine derivative of triazole is selected from one or more of 1-[di-(4-butylphenyl)aminomethyl]triazole, 1-[di-(4-octylphenyl)aminomethyl]triazole, 1-[di-(4-nonylphenyl)aminomethyl]triazole, 1-[(4-butylphenyl)(phenyl)aminomethyl]triazole, 1-[(4-octylphenyl)(phenyl)aminomethyl]triazole, 1-[(4-nonylphenyl)(phenyl)aminomethyl]triazole and 1-[(4-butylphenyl)(4-octylphenyl)aminomethyl]triazole.

8. A method of reducing high temperature copper and lead corrosion in a heavy duty diesel engine oil, comprising between about 50 ppm and about 800 ppm molybdenum, the method comprising the step of adding to the engine oil an alkylated diphenylamine derivative of triazole at between 0.05% and 3.0% by weight of the engine oil, wherein the alkylated diphenylamine derivative of triazole excludes derivatized tolutriazoles and derivatized benzotriazoles.

9. The lubricating composition of claim 1, wherein the lubricating oil is one that is determined to be corrosive to Cu and/or Pb according to the High Temperature Corrosion Bench Test ASTM D 6594 when component (B) is not present.

10. An additive composition for use with a lubricating oil composition, the additive composition comprising (A) an organo-molybdenum composition, and (B) an alkylated diphenylamine derivative of triazole, wherein (B) excludes derivatized tolutriazoles and derivatized benzotriazoles, and the ratio of (A):(B) based on the amount of molybdenum by weight and the amount of triazole derivative by weight is from about 0.001:1 to 20:1.

11. A composition according to claim 10 where the triazole derivative is selected from one or more of 1-[di-(4-alkylphenyl)aminomethyl]triazole or 1-[di-4-alkylphenyl)(phenyl)aminomethyl]triazole.

12. A composition according to claim 11 where the triazole derivative is chosen from the group consisting of one or more of 1-[di-(4-butylphenyl)aminomethyl]triazole, 1-[di-(4-octylphenyl)aminomethyl]triazole, 1-[di-(4-nonylphenyl)aminomethyl]triazole, 1-[(4-butylphenyl)(phenyl)aminomethyl]triazole, 1-[(4-octylphenyl)(phenyl)aminomethyl]triazole, 1-[(4-nonylphenyl)(phenyl)aminomethyl]triazole and 1-[(4-butylphenyl)(4-octylphenyl)aminomethyl]triazole.

13. A composition according to claim 10, wherein the organo-molybdenum compound is one or both of molybdenum dithiocarbamate and molybdenum ester/amide complex.

14. The method according to claim 8, wherein the reduction of copper and/or lead corrosion is according to the High Temperature Corrosion Bench Test ASTM D 6594.

15. The method according to claim 8, wherein the molybdenum is present in the form of one or both of a molybdenum dithiocarbamate and a molybdenum ester/amide complex.

16. The method according to claim 8, wherein the triazole derivative is chosen from the group consisting of one or more of 1-[di-(4-butylphenyl)aminomethyl]triazole, 1-[di-(4-octylphenyl)aminomethyl]triazole, 1-[di-(4-nonylphenyl)aminomethyl]triazole, 1-[(4-butylphenyl)(phenyl)aminomethyl]triazole, 1-[(4-octylphenyl)(phenyl)aminomethyl]triazole, 1-[(4-nonylphenyl)(phenyl)aminomethyl]triazole and 1-[(4-butylphenyl)(4-octylphenyl)aminomethyl]triazole.

Description

EXAMPLES

HTCBT Corrosion (Examples 1A through 1J)

(1) Corrosion potential of these lubricants towards copper and lead metals was evaluated using the high temperature corrosion bench test (HTCBT) according to the ASTM D 6594 test method. Details of the test method can be found in the annual book of ASTM standards. For the test specimen 1002 grams of lubricant was used. Four metal specimens each of copper, lead, tin and phosphor bronze were immersed in a test lubricant. The test lubricant was kept at 135 C. and dry air was bubbled through at 50.5 L/h for 1 week. The API CJ-4 specifications for heavy duty diesel engine oil limits the metal concentration of copper and lead in the oxidized oil as per ASTM D 6594 test methods to 20 ppm maximum and 120 ppm maximum respectively. After testing, the lubricants were analyzed for the Cu and Pb metal in the oil using the Inductive Coupled Plasma (ICP) analytical technique.

(2) In Tables 1, 2 and 3, base blend is an SAE 15W-40 SAE viscosity grade fully formulated heavy duty diesel engine oil consisting of base oils, dispersants, detergents, VI Improvers, antioxidants, antiwear agents, pour point depressants and any other additives. Base blend is then further formulated as described in the examples 1A to 1J. The 100% active alkylamine derivative of triazole used was IRGAMET 30, 1-(N,N-bis(2-ethylhexyl)aminomethyl)-1,2,4-triazole available from BASF Corporation. The molybdenum dithiocarbamate used was MOLYVAN 3000, a 10 wt. % molybdenum thiocarbamate available from Vanderbilt Chemicals, LLC. The molybdenum ester/amide used was MOLYVAN 855, an 8 wt. % sulfur-free organo-molybdneum product available from Vanderbilt Chemicals, LLC.

(3) The results in Table 1 clearly show that all three triazole derivatives are effective at reducing copper and lead corrosion in the HTCBT test when molybdenum is present in the heavy duty diesel engine oil formulations. The results also show that the mixed butylated/octylated diphenylamine derivative of triazole prepared in Example P-2 is about as effective as the alkylamine derivative of triazole at reducing corrosion when molybdenum is present.

(4) TABLE-US-00001 TABLE 1 1A 1B 1C 1D base blend (wt %) 99.64 99.44 99.24 99.24 molybdenum dithiocarbamate 0.16 0.16 0.16 0.16 (wt %) molybdenum ester/amide (wt %) 0.2 0.2 0.2 0.2 100% active alkylamine derivative 0.2 of triazole (wt %) 50% active dioctylated 0.4 diphenylamine derivative of triazole (wt %) Example P-1 50% active mixed butylated/ 0.4 octylated diphenylamine derivative of triazole (wt %) Example P-2 Total (wt %) 100 100 100 100 Mo (ppm) 320 320 320 320 ASTM D6594 Cu (ppm) Run 1 225 7 51 8 Cu (ppm) Run 2 265 6 48 7 Cu (ppm) Run 3 272 384 600 6 Pb (ppm) Run 1 101 47 67 40 Pb (ppm) Run 2 116 43 99 50 Pb (ppm) Run 3 82 102 14 42

(5) The results in Table 2 clearly show that when one type of organo-molybdenum is used, in this case the molybdenum ester/amide, the use of alkylated diphenylamine derivatives of triazole (samples prepared in examples P-1 and P-2) are effective at reducing either copper or lead corrosion, or both, as measured in the HTCBT.

(6) TABLE-US-00002 TABLE 2 1E 1F 1G base blend (wt %) 99.8125 99.2 99.2 molybdenum ester/amide (wt %) 0.1875 0.4 0.4 50% active dioctylated diphenylamine 0.4 derivative of triazole (wt %) Example P-1 50% active mixed butylated/octylated 0.4 diphenylamine derivative of triazole (wt %) Example P-2 Total (wt %) 100 100 100 Mo (ppm) 150 320 320 ASTM D6594 Cu Run 1 46 29 7 Cu Run 2 405 7 8 Cu Run 3 172 7 7 Pb Run 1 144 48 117 Pb Run 2 11 96 131 Pb Run 3 140 122 112

(7) The results in Table 3 clearly show that when one type of organo-molybdenum is used, in this case the molybdenum dithiocarbamate, the use of alkylated diphenylamine derivatives of triazole (samples prepared in examples P-1 and P-2) are effective at reducing either copper or lead corrosion, or both, as measured in the HTCBT.

(8) TABLE-US-00003 TABLE 3 1H 1I 1J Base blend (wt %) 99.85 99.28 99.28 Molybdenum dithiocarbamate (wt %) 0.15 0.32 0.32 50% active dioctylated diphenylamine 0.4 derivative of triazole (wt %) Example P-1 50% active mixed butylated/octylated 0.4 diphenylamine derivative of triazole (wt %) Example P-2 TOTAL 100 100 100 Mo (ppm) 150 320 320 ASTM D6594 Cu Run 1 10 258 27 Cu Run 2 402 13 28 Cu Run 3 72 13 62 Pb Run 1 46 5 22 Pb Run 2 6 28 38 Pb Run 3 44 26 14

Fluoroelastomer Seal Compatibility (Examples 2A through 2H)

(9) Engine oil compatibility with typical seal elastomers were evaluated according to the procedure described in the ASTM D7216. The elastomer used for the evaluation was fluoroelastomer, commonly known as FKM. FKM is one of the typical sealing materials used in automotive applications in contact with engine oil. Compatibility of elastomer is evaluated by determining the changes in hardness and tensile properties when the elastomer specimens are immersed in the test lubricant for 3360.5 hours at 150 C. Tensile properties and hardness of elastomers were evaluated according to the procedure described in the ASTM D471 and ASTM D2240 respectively. ILSAC GF-5 specification limits the changes in the tensile properties and hardness to (65, +10) and (6, +6) respectively. The results are reported in Table 4.

(10) TABLE-US-00004 TABLE 4 2A 2B 2C 2D 2E 2F 2G 2H Base blend (wt %) 100 99.64 99.8 99.6 99.6 99.44 99.24 99.24 Molybdenum ester/amide (wt 0.2 0.2 0.2 0.2 %) Molybdenum dithiocarbamate 0.16 0.16 0.16 0.16 (wt %) 100% active alkylamine 0.2 0.2 derivative of triazole (wt %) 50% active dioctylated 0.4 0.4 diphenylamine derivative of triazole (wt %) Example P-1 50% active mixed 0.4 0.4 butylated/octylated diphenylamine derivative of triazole (wt %) Example P-2 TOTAL 100 100 100 100 100 100 100 100 Change in Tensile Strength 40.09 36.61 56.83 40.51 38.69 55.75 37.94 37.36 (%) Change in Hardness 3.8 3.9 5.1 3.2 3.8 4.8 3.0 3.8

(11) Table 4 clearly shows that the base blend plus molybdenum (2B) and the base blend plus the alkylated diphenylamine derivatives of triazole (2D and 2E) are not detrimental, or are considered neutral, towards fluoroelastomer seal degradation. This is evidenced by virtually no change in tensile strength or hardness when moving from 2A to either 2B, 2D or 2E. Note, the formulations of this invention 2G and 2H are also neutral to fluoroelastomer seal degradation. However, formulations containing alkylamine derivatives of triazole (2C and 2F) show a substantial increase in tensile strength and hardness indicating that the alkylamine derivatives of triazole are detrimental to fluoroelastomer seals.

(12) Thus the novel formulations comprising (a) an organo-molybdenum compound, and (b) an alkylated diphenylamine derivative of triazole, can provide very effective protection against Cu and/or Pb corrosion as determine by ASTM D 6594, as well as being completely neutral towards the degradation of fluoroelastomer seals. It has been shown above, while the alkylamine derivatives of triazole are also effective at reducing Cu and Pb corrosion as determined by ASTM D 6594, they are severely detrimental towards flouroelastomer seal degradation, and thus do not provide a practical solution to the Cu and Pb corrosion problem.

HTCBT Corrosion (Examples 3 through 7)

(13) In Table 5, base blend is SAE 0W-20 viscosity grade fully formulated engine oil consisting of base oils, dispersants, detergents, VI Improvers, antioxidants, antiwear agents, and pour point depressants. Base blend is then further formulated as described in the examples shown in table 5.

(14) Corrosivity of these formulations towards copper and lead metals was evaluated using high temperature corrosion bench test (HTCBT) according to the ASTM D 6594 test methods and the modified HTCBT method. In the modified HTCBT method, the test lubricant was kept at 165 C. and dry air was bubbled through the lubricant at 50.5 L/h for 48 hours. After the test, the lubricants were analyzed for the Cu and Pb metal in the oil using Inductive Coupled Plasma (ICP) analytical technique.

(15) Example 3 shows the effect adding molybdenum has to increase Cu and Pb corrosion in heavy duty diesel engine oil according to ASTM D 6594 and the modified HTCBT test. Examples 4 and 5 show the beneficial properties of alkylamine derivatives of triazole as previously discussed. Although the alkylamine derivatives of triazole are effective at reducing corrosion, Examples 2C and 2F above clearly show that they are very detrimental to seal compatibility. Example 6 is a comparative example using N,N-Bis(2-ethylhexyl)-ar-methyl-1H-benzotriazole-1-methanamine, an alkylamine derivative of tolutriazole corrosion inhibitor available from Vanderbilt Chemicals, LLC as CUVAN 303. Example 7 is a comparative example using 2,5-dimercapto-1,3,4-thiadiazole derivative, a sulfur-based corrosion inhibitor available from Vanderbilt Chemicals LLC as CUVAN 826. Examples 6 and 7 clearly show that the comparative corrosion inhibitors are not as effective as the triazole corrosion inhibitor in example 4.

(16) TABLE-US-00005 TABLE 5 Examples 3 4 5 6 7 1 Base Blend* 99.637 99.437 99.437 99.437 99.437 2 Molybdenum Ester/Amide (wt %) 0.2 0.2 0.2 0.2 0.2 3 Molybdenum 0.163 0.163 0.163 0.163 0.163 Dithiocarbamate (wt %) 4 100% active alkylamine 0.2 derivative of triazole (wt %) 5 100% active alkylamine 0.2 derivative of triazole (wt %) alternative source 6 N,N Bis(2-ethylhexyl)-ar- 0.2 methyl-1H-benzotriazole-1- methanamine 7 2,5 dimercapto-1,3,4- 0.2 thiadiazole derivative 8 Total 100 100 100 100 100 ASTM D6594 Cu (20 ppm max.) Run 1 97 4 4 4 390 Cu (20 ppm max.) Run 2 101 4 12 2 366 Pb (120 ppm max.) Run 1 41 2 <1 13 114 Pb (120 ppm max.) Run 2 52 1 224 190 102 Modified HTCBT Method Cu (20 ppm max.) Run 1 164 6 4 26 50 Cu (20 ppm max.) Run 2 164 4 3 25 214 9 Pb (120 ppm max.) Run 1 28 8 2 14 6 10 Pb (120 ppm max.) Run 2 20 22 2 165 17

Example P-1: Preparation of 1-(N,N-bis(4-(1,1,3,3-tetramethylbutyl)phenyl)aminomethyl)-1,2,4-triazole in 50% Process Oil

(17) In a 500 mL three-necked round bottom flask equipped with a temperature probe, overhead stirrer and Dean Stark set up were charged VANLUBE 81 (dioctyl diphenylamine) (62.5 g, 0.158 mole), 1,2,4-triazole (11.0 g, 0.158 mole), paraformaldehyde (5.5 g, 0.158 mole), water (3 g, 0.166 mole) and process oil (37.7 g). The mixture was heated under nitrogen to 100-105 C. with rapid mixing. Mixing was continued at 100 C. for one hour. After one hour, water aspirator vacuum was applied and the reaction temperature was raised to 120 C. The reaction mixture was held at this temperature for an hour. The expected amount of water was recovered, suggesting a complete reaction occurred. The reaction mixture was allowed to cool to 90 C., and transferred to a container. A light amber liquid (102.93 g) was isolated.

Example P-2: Preparation of Mixed Butylated/Octylated Diphenylamine Derivative of 1,2,4-triazole in 50% Process Oil

(18) In a 500 mL three-necked round bottom flask equipped with a temperature probe, overhead stirrer and Dean Stark set up were charged VANLUBE 961 (mixed butylated/octylated diphenylamine) (60 g, 0.201 mole), 1,2,4-triazole (13.9 g, 0.200 mole), paraformaldehyde (6.8 g, 0.207 mole), water (3.8 g, 0.208 mole) and process oil (77 g). The mixture was heated under nitrogen to 100-105 C. with rapid mixing. Mixing was continued at 100 C. for one hour. After one hour, water aspirator vacuum was applied and the reaction temperature was raised to 120 C. The reaction mixture was held at this temperature for an hour. The expected amount of water was recovered, suggesting a complete reaction occurred. The reaction mixture was allowed to cool to 90 C., and transferred to a container. A dark amber liquid (138.86 g) was isolated.