CA1159045A

CA1159045A - Lubricant composition with stabilized metal detergent additive and friction reducing ester component

Info

Publication number: CA1159045A
Application number: CA000378153A
Authority: CA
Inventors: David H. Rehrer
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1980-06-09
Filing date: 1981-05-22
Publication date: 1983-12-20
Also published as: EP0041851A3; BR8103615A; EP0041851A2; DE3162777D1; EP0041851B1; JPS5723692A

Abstract

ABSTRACT OF THE DISCLOSURE

Oils with metal sulfonate or sulfurized phenate detergents and friction reducing dicarboxylic esters are stabilized against haze or sediment formation by treat-ment of this oil solution of metal additive, prior to ester incorporation, with a phosphosulfurized polyiso-butylene or a polyisobutenyl succinic anhydride at 55°
to 225°C for 2-30 hours.

Description

3 ~

1 This invention relates to oil compositions

2 which contain both an overbased metal detergent addi-

3 tive and a glycol ester friction modifier. More parti-

4 cularly, this invention relates to a method for formulat-ing such compositions,wherein ~et formation of haze and 6 sediment due to the -L~ ~ ~ of these additives is 7 overcome.
8 Lubxicating oil compositions containing metal de-9 tergent additives being either the normal or basic (over-based~ magnesium or calcium sulfurized phenates or sulfon-11 ates are well known in the art and are employed in various 12 motor oil formu'ations. ~ormulating these metal detergent 13 additives with other ingredients in a finished lubricating 14 oil blend has been known to create compatibility problems, specifically the formation of ~ediment, separation of 16 phases, visible precipitation or haze and similar problems -17 which are evidence of incompatibility or unwanted inter-18 action of components~
19 Resolution of this problem through techniques known in the art is represented by U.5. Patent 3,714,042, 21 issued January 30, 1973 to Greenough, which discloses the ~2 trea~ment of overbased complexes with a high molecular 23 weight aliphatic carboxylic acid or anhydride at elevated 24 temperatures. U.S. Patent 3,965,017, issued to Burnop et al discloses stabilization through addition of small 26 proportions of a monocarboxylic acid, anhydride or salt 27 or the reaction product of a hydrocarbon with P2S5 and a 28 glycol or ether alcohol.
29 Lubricant compositions containing the polycar-boxylic acid-glycol ester friction modifier addit7ve used 31 in the compositions of the ~resent invention are disclosed 32 in U.S. Patent 4,105,571 issued to Shaub et al.
33 The present invention is concerned with resolu-34 tion of the s~ecific problem of lncompatibility encountered when lubricating oil formulations are prepared which con-36 tain both a metal or overbased metal sulfonate or a - -. -, ,. .:,.... :

3 ~

1 sulfurized phenate detergent additive, particularly 2 where the metal is calcium or magnesium, and small pro-3 portions of a glycol-polycarboxylic acid ester friction 4 reducing additive.
In accordance with the present invention, there 6 is provided a lubricating oil composition having a reduced 7 tendency toward sediment formation,which comprises a glycol-8 polycarboxylic acid ester friction reducing additive and a 9 metal deteryent additive being a metal or overbased metal sulfonate or sulfurized phenate.which com~osition is prepared by 11 a process comprisinq the ste~s of:
12 (a) providing a lubricating oil mixture contain-13 ing a lubricating oil base stock containing 14 about 0.1 to 10 percent by weight of a metal or overbased metal sulonate or sul'urized 16 phenate detergent additive;
17 (b) treating said mixture by reacting said meta].
18 detergent additive with from about 50 to 19 100 percent by weight, based upon the weight of the metal detergent additive, with either 21 (i) a phosphosulf~rized polyisobutylene or 22 (ii) a polyisobutenyl succinic anhydride 23 at temperatures of from about 55C to about 24 225C for a period of from about 2 to 30 hours; and 26 (c) thereafter, adding to said treated mixture 27 about 0.01 to about 2.0 percent by weight, 28 based on the total weight of the com~osî-tion, of said qlycol ester friction modi-fier additive, whereby said composition ex-31 hib~ts a reduced tendency toward phase sepa-32 ration or sediment or haze formation.

33 The metal detergent additives used in the present 34 invention are those metal or overbased metal sulfonate or sulfurized phenate oil-soluble additives which are well 36 known in the art. The metal s~lfonates are obtained from .
~ .
, -: .

S

l sulfonic acids derived from sulfonating natural or syn-; 2 thetic hydrocarbons, such as bv treating oil base St~k~
3 with concentrated or fuming sulfuric acid or by sulfonat~
4 ing alkylated aromatic hydrocarbons. The hydrocarbyl sulfonate o~ these metal detergent additives is derived 6 from petroleum sulfonates and includes a:Lkyl, alkylaryl 7 and aryl sulfonates and mixtures thereof having a molecular 8 weiqht of from about 300 to l, n~n, such as barium nonyl-9 benzene sulfonate, magnesium dodecylbenzene sulfonate and the like. The sulfonates are usually the alkaline earth 11 metal sulfonates, usually calcium, barium, or magnesium, 12 but can also be alkali metal sulfonates, such as sodium 13 sulfonates. Overbased sulfonates are those which contain 14 metal base in excess that is re~uired for simple neutrali-zation. In preparing such overbased materials, the sul~on-16 ic acid is typically reacted with an excess o~ metal base 17 and the excess base is usually neutralized with an acidic qas, such as carbon dioxide. Such overbased sulfonates 19 have a total base number (ASTM-D-664) o~ about 50 to 500.
The sulfurized phenates are the metal salts of sul-~1 furized alkyl phenols, which contain about 2 to 14 percent 22 hy weight sulfur based on the weight of the sulfuri~ed 23 alkyl phenols. Such materials are well known in the art 24 and are derived from alkylated phenols, wherein the alkyl is C5-C40, such as t-amyl phenol, t-octyl phenol, nonyl-2~ phenol, di-t-octyl phenol and phenols alkylated with suit-~7 ahle polymers of up to 40 carbon atoms obtained from propyl-29 ene, butylene, amylenes or mixtures thereof. The sulfur-29 ized phenols are prepared by well-known methods, for ex-ample, by reacting the alkylated phenol wi~h sulfur mono-31 chloride, sulfur dichloride or elemental sulfur.
32 The metals employed for providing ~he phenate salts 33 are typically alkali metal, alkaline earth metal or mag-34 nesium, principally calcium or magnesium. Overbased phe-nates are prepared by the process comprising reacting the 36 phenol with excess base and the excess is neutrali~ed with ,.
I

..

., 1 carbon dioxide. Typical overbased metal sul~urized phe-2 nates will have a total base number (ASTM-D-664) of about 3 50 to 100.
4 The treatment step of the present invention gener-ally comprises incorporating the metal detergent additive 6 into a lubricating oil and conducting a reaction ~or about 7 2 to 30 hours at temperatures of from about 55C to 225C
8 with either a phosphosulfurized polyisobutylene or with a 9 polyisobutenyl succinic anhydride, and 25-100 percent, ~ref-erably 50-100, percent by weight of these materials are 11 used based upon the weight of the metal detergent additive 12 present.
13 When employing a phosphosulfurized polyisobutylene, 14 it is preferable in most cases to conduct the treatment step of the present invention at relatively higher tempera-16 tures and longer periods of time. Thus, the preferred 7 treatment conditions for P2S5-polyisobutylene treatment 8 are tempera~ures o~ about 100C to 200C and a treatment 19 period oE about 10 to 25 hours, particularly when the metal additive is an overbased calcium or magnesium sulfurized I phenate~
22 ~hen the polyisobutenyl succinic anhydride is em-3 ployed, preferred conditions of treatment in accordancewith this invention are temperatures of about 60C to 85C for about 2 to 7 hours.
26 Phosphosulfurized polyisobutylenes useful in the 7 present invention are prepared by methods well known in the art comprising the reaction of sulfides of phosphorous 29 with polyisobutylene at elevated temperatures. While P2S5 31 P rred, P2S3, P4S3 and P4S5 are also useful as well as mixtures thereof, as well as mi~tures of elemental phos-phorous a~d sulfur. The reaction is ~ out at about 90C to 315C, preferably 150C, to 290C, using about 1 to 5 molar proportions o~ polyisobutylene to 1 molar proportion of phosphorous sulfide. The reaction is usually continued until the ma~imum amount of sulfur or phosphorous 37 sulfide has been added but this is not essential to provide :
.

.: ; ~, ' 1 a useful product. Typical reaction times are about 2 to 2 10 hours. Generally, the polyisobutylenes have a molec-3 ular weight of about 500 to 25,000, preferably 800 to 4 2,000. Particularly useful are polyisobutylenes of 700 ~o 1500 molecular weight reacted with about 10 to 15 percent 6 by weight of P2S5.
7 The polyisobutenyl succinic anhydrides useful 8 herein for treating the metal detergent additives are also 9 known and are disclosed in the number of re~erences, such as U.S. Patent 3,288,714, issued to Osuch. These are oil 11 soluble materials, which have desirable additive properties 12 themselves, principally as dispersants, prepared by react-13 ing maleic anhydride with a polyisobutylene polymer having 14 a molecular weight of about 500 to 2,000. Particularly preferred for use as treating agents in the present inven-16 tion are those polyisobutenyl succinic anhydrides wherein 17 the polyisobutenyl group has a number average molecular 18 weight of about 700 to 1,500.
19 The lubricating oil base stock employed herein 20 generally comprises a hydrocarbon mineral oil of lubricating 21 viscosity includinq ~araffinic! na~hthenic and aromatic oils preferably a mineral paraffinic oil havinq a viscosity of 23 about 20 to 100 cs. min. (10QF) and blends of such mineral 24 paraffinic oils. Synthetic oils may be used provided the 25 conditions of treatment do not adverselY affect such sYn 26 thetic oils bY causinq an unwanted side re~tl~n.
27 The finished formulation then may be prepared 28 by incorporating into the treated composition the friction 29 reducing polycarboxylic acid glycol ester whlch is employed 30 in amounts of about 0.01 to 2.0 percent preferably 0.05 to 31 o 3 percent by weight, typically, 0.1 to 0.3 percent by weight based upon the total weight of the composition being used.

These friction reducing esters are descr~ in more detail hereinkelow.
34 The friction reducing esters are generally de-35 rived from the esterification of a polycarboxylic acid with 36 a glycol and may be partial esters or diesters of the formulas:

: . . . . ...

1 HO-R'-OOC-R-COOH and HO-R'-OOC-R-COOR"-OH
2 wherein R i5 the hydrocarbon radical of the acid and R' 3 and R" is either the hydrocarbon radical of an alkane diol 4 or the oxyalkylene radical from an oxa-alkane diol as ae-fined hereinhelow. The polycarboxylic acid may be an ali-6 phatic saturated or unsaturated acid and will generally 7 have a total of about 24 to 90, preferably about 24 to 60, 8 carbon atoms and about 2 to 3, preferably about 2, carbox-9 ylic acid groups with a least about 9 carbon atoms, prefer-ably about 12 to 42, especially 16 to 22 carbon atoms be-11 tween the carboxylic acid groups. Generally about 1-3 12 moles of glycol, preferably 1-2 moles of glycol, is used 13 per mole of acid to provide either a complete or partial 14 ester. Esters within the foregoing formula can also be prepared by reaction of the acid with 1 mola or more of 16 ethylene o~ide.
17 Also, esters can be obtained by esterifying a 18 dicarboxylic acid or mixture of such acids with a diol or 19 mixture of diols, R would then be the hydrocarbon radical of the dicarboxylic acid and R' and R" would be the hydro-21 carbon radical associated with the diols or diols.
2~ Especially preferred are the dimer acid ester 23 friction reducing esters. The term dimer acid used herein ~4 is meant to refer to those substituted cyclohexene dicar-boxylic acids formed by a Diels-Alder-type reaction which 26 is a thermal Gondensation of C18-C22 unsaturated fatty 27 acids~ such as tall oil fatty acids which typicallv con-28 tain about 85 to 90 percent oleic or linoleic acids. Such 29 dimer acids typically contain about 36 carbon atoms. The dimer acid structure can be generalized as follows:

32 IRl 33 f'` /R2 34 ~1 \

36 ~ ~3 ., ' , , , I
.

l with two of the R groups being carboxyl groups and two 2 being hydrocarbon groups depending upon how the conden-3 sation of the carboxylic acid has occ~red. The car-4 boxyl groups can be -(C~I2)~COOH;-CH=CH(CH2)7COOH; (CH2)7 S COOH; -c~2cH=cH(cH2)7coo~;-CH=CH(cH2)7coo~ and the hydro-6 carbon terminating group can be represented by: CH3(CH2)4;
7 CH3(CH2)5-;C~3(C~)7;-CH3(CH2)4CH=CH-;CH3(CH2)4CH=C~ CH2-;
8 CH3(CH2)~CH=CH CH2-; and the like. The dimer of linoleic 9 acid which is the preferred embodiment can be expressed in the following formula:
)7COOH
13 ~ CH=CH(CH2)7COOH

~ /\
16 ~ ~CH2)5CH3 17 (CH2)5CH3 18 Also the term dimer acid as used herein neces-19 sarily includes products containing up to about 24 per~
cent by weight trimer, but more typically about 10 per-21 cent by weight trimer since, as is well known in the art, 22 the dimerization reaction provides a product containing 23 a trimer acid having molecular weight of about three times 24 the molecular weight of the starting fatty acid.
~5 The polycarboxylic acids or dimer acids noted 26 above are esterified with a glycol, the glycol being an 27 alkane diol or oxa-alkane diol represented by the formula 28 HO(RCHCH2O)XH wherein R is H or C~3 and x is about 2 to 29 100, preferably 2 to 25, with ethylene glycol and dieth-ylene glycol particularly preferred. A preferred embodi-31 ment is formation of the ester with about 1 to 2 moles 32 of glycol per mole of dimer acid or polycarboxylic acid, 33 such as the ester of diethvlene qlYcol with dimerized 34 linoleic acid.

Numerous other additives will of course normally 36 be included in a finished lubricating oil composition such ,: ~ . , - - : ~
' - - \
`I 15~d4~

1 as detergents and dispersants, oxidation and rust in-2 hibitors, viscosity index improvers, pour depressants, 3 anti-wear agents and the like and these may be added 4 prior to or subsequent to the addition of the friction reducing ester component.

7 Formulations were prepared which demonstrated 8 the incsmpatibility of the metal detergent additive with 9 a dimer acid ester friction modifier which in each formu-lation was diethy}ene glycol es~er of dimerized linoleic 11 acid. In each formulation set forth in Table I, the com-12 position was cloudy with visible separation of phases after 13 standing for several days both at room temperature and at 14 65C. The base oil in each case was Solvent 150 Neutral oil, a mineral paraffinic oil having a viscosity of 31 cS.
16 min. at 37.8C.

._ .
18 Component Formulation - Wei~ht Percent 20 Overkased Ca ~ furized 1.0 21 P~te (1) 22 Overbased Mg Sul~urized ~ -~ ~ ~ ~
23 Phenate (2) 24 Overba~ ~g Sulfonate (3) ~ ~ 1.04 - -25 Overbased Ca Sulfonate (4) - - - - 1.5 26 Ca Sulfurized Phenate (5) - ~ ~ 1.5 27 Base Oil 98.9 99.1 98.86 98.4 98.4 28 Friction Mcdifier ~.1 0.1 0.1 0.1 0.1 29 In each formulation of Table I, in the absence 30 of the friction modifier additive the formulations were 31 clear with no evidence of instability after storage for 32 equivalent periods of time under the same conditions.
33 Total base numbers reported are according to ASTM-D-664.
34 (1) Over~ased calcium sulfurized dodecyl phenate sulfide having a total base number of 250.

~......

., ~

. . . .. .

: . , " , 3 ~
g 1 (2) Overbased magnesium sulfurized nonylphenate, nonyl-2 phenol sulfide having a total base number of 250.
3 (3) Overbased magnesium alkyl sulfonate having a total : 4 base number of 395.
(4) Overbased calcium alkyl sulfonate having a total 6 base number of 300.
7 (5) Calcium sulfurized dodecyl phenate having a total 8 base number of 135.
9 A number of stabilized formulations were prepared by first treating an oil concentrate containing 20-30 wt.
11 percent of the metal detergent additive wlth a P2S5-12 polyisobutylene (mol. wt. 780) and then blending with the 13 base oil and friction modifier to provide the finished 14 formulation. These are set forth in Table II which in-cludes the various treatment times and temperatures used;
16 all formulations were clear with no evidence of instability 17 upon standing for 1 month at room temperature and 1 month 18 at 65C. The metal additives and friction modifier are the 19 same as those reported in Table I.
Similarly, metal detergent additives were treated 21 with two types of polyisobutenyl succinic anhydrides; for-22 mulations A & B used Mn=1,000 and Sap No. 112 and formula-23 tions C & D used Mn=1,300 and Sap. No. 103 under varying 24 conditions of time and temperature and, thereafter, the treated materials were blended into the formulations re-26 ported in Table III each of which remained clear upon stor-27 age for 1 month at room temperature and 1 month at 65C
28 with no instability apparent. Again, the base oil, ad-29 ditives and friction modifiers are those identified in the prioF examples.

., , i ,~ `! ': . , T~BLE II
2 Formulation - Weight Percent 3 Canmnent A B C D E
-4 Overbased Ca Sulfurized 1.0 S Phenate 6 Overbased Mg Sulfurized 1 10 - - -7 Phenate 8 Overbased ~$g Sulfonate - - 1.0 9 Ca Sulfurized Phenate - - - 1.0 Over~sed Ca Sulfonate - - ~ ~ 1.0 11 P2S5 - Polyiso~utylene 0.5 10 0.10.5 0.5 12 Base Oil 98.5 79.8 98.8 98.4 98.4 13 Friction Mcdifier0.1 0.2 0.1 0.10.1 ~5 Trea~nent Conditions __ - 16 ~urs 20 24 7 1~ 17 17 T~[~ature C 152 2000 59 68 64 19 T~LE III
Formu~Ltion_ -_ Wi3ight Percen~
21 Ca~ent A B C D
22 Overbased Mg Sulfurized1.0 - 1.0 23 Phenate 24 Overbased Ca Sulfurized - 1.0 - 1.0 Phenate 26 Polyisobuten~l Succinic0.5 0.2 0.5 0.5 27 Anhydride 28 Ea~e Oil 98.7 98.498.4 29 Eriction Modifier0.1 0.1 0.1 0.1 31 T.reat~nt Conditions 3 2 ~urs 4 5 24 24 33 Te~ature C 64 70 82 82 ~ ' :
.

~ . ..

1 Instead of carrying out the treatment of the deter-2 gent additive in a lubricating oil, the same results are 3 obtained by carrying out the treatment in a lubricating 4 oil concentrate wherein said detergent additive is present in amounts of 20 to 50 wt. percent, based on the total oil 6 composition, the base oil comprising 50 to 80 percent of 7 the composition, or a portion of the oil may be replaced 8 by other additives, such as viscosity index improver, pour 9 depressants, dispersants, etc. Thus, 0.1 to 50 wt.
percent of the detergent additive admixed with the oil 11 can be used in the reaction with said phosphosulfurized 12 polyisobutylene or anhydride reactants.

- . . . .

~, '. : ~

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An oil composition comprising a lubricating oil base stock, a polycarboxylic acid glycol ester fric-tion modifier additive and a metal or overbased metal sulfonate or sulfurized phenate detergent additive which composition is prepared by a process comprising the steps of: (a) providing a mixture containing a lubricating oil base stock and about 0.1 to 50 percent by weight of the metal detergent additive; (b) treating said mixture by reacting it with 25 to 100 percent by weight, based on the weight of the metal detergent additive, with either a phosphosulfurized polyisobutylene or a polyisobutenyl succinic anhydride at temperatures of from about 55° to about 225°C for about 2 to 30 hours, and (c) thereafter adding to said treated mixture about 0.01 to about 2.0 percent by weight, based on the total weight of the composition, of the glycol ester friction modifier addi-tive, whereby said composition exhibits a reduced tendency toward sediment formation or phase separation.

2. The composition of claim 1 wherein the metal detergent additive is an overbased calcium or magnesium sulfonate.

3. A composition of claim 1 wherein the metal detergent additive is an overbased calcium or magnesium sulfurized phenate.

4. The composition of claims 1 or 2 wherein said treatment step is conducted with a polyisobutenyl succinic anhydride wherein the polyisobutenyl group has a molecular weight of from about 700 to 1,500.

5. The composition of claim 1 wherein the friction modifier is the diethylene glycol ester of the dimer acid of linoleic acid.

6. The composition of claim 5 wherein the concentration of said glycol ester is from about 0.05 to about 0.3 weight percent.

7. The composition of claim 1 wherein said treatment step is conducted with a polyisobutylene of 700 to 1500 molecular weight phosphosulfurized with P2S5.

8. The composition of claim 1 wherein said treatment step is conducted at a temperature of from about 100°C to 200°C for a period of about 10 hours to 25 hours.

9. The composition of claim 1 wherein the treat-ment is conducted at a temperature of from about 60° to 85°C for about 2 to 7 hours.

10. The composition of claim 1 wherein said treatment is carried out on a mixture containing said lubricating oil base stock and about 0.1 to 10 percent by weight of said metal detergent additive, using 50 to 100 percent by weight, based on the weight of said metal de-tergent additive, of said phosphosulfurized polyisobutyl-ene or of said anhydride.