Note: Descriptions are shown in the official language in which they were submitted.
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1LUBRICATING OIL COMPOSITION CONTAINING
25EDIMENT-REDUCING ADDITIVE
This invention relates to storage stable lubri-
~A~ cating oil compositions containing an additive package
which provides both dispersant and friction modification
6 properties. More particularly, this invention relates
7 to a formulated lubricating oil composition containing a
8 polycarboxylic acid-glycol ester friction modifier and
g an alkenyl succinimide dispersant having a reduced ten-
dency to form sediment upon storage.
11 Lubricating oil compositions which contain
12 polycarboxylic acid-glycol esters as friction reducing
13 components are known in the art and are disclosed, for ex- -
14 ample, in U.S. Patent 4,105,571 issued August 8, 1978 to
Shaub et al. The oil-soluble alkenyl succinimide disper-
16 sants, particularly polyisobutenyl succinimide disper-
17 sants, are well known and are disclosed in U.S. Patent
18 3,172,892, issued March 9, 1965 to Le Suer et al., and
19 U.S. Patent 3,933,659, issued January 20, 1976 to Lyle
et al.
21 It is known that lubricating oil compositions
22 containing the aforesaid alkenyl succinimide dispersants
23 and polycarboxylic acid-glycol ester friction modifiers
24 offer a ~umber of advantageous properties, however, a
problem frequently encountered is the tendency of appre-
26 ciable quantities of sediment to form upon storage of
27 formulated compositions containing these additives and
28 other conventionally employed additives, especially metal
~9 containing additives. The present invention deals with
this problem by providing additives found effective in
31 stabilizing such compositions against sediment formation,
32 the stabilizer additives being certain polyol-fatty acid
33 esters or ethoxylated fatty acids, amines or amides.
34 Shaub et al in U.S. Patent 4,105,571 disclose
35 that incompatibility problems of zinc dihydrocarbyl di-
36 thiophosphate and glycol ester friction-reducing compon-
37 ents can be resolved by pre-dispersing ei*her component
38 in an ashless dispersant prior to combining them in the
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1 lubricating o~l formulation; however, 5haub et al do note
2 that formulations containing dispersants based on a re-
3 action product of polyisobutenyl succinic anhydride and
4 polyamine exhibited evidence of storage instability and
suggested that an increased amount of dispersant may be
6 necessary to maintain compatibility. The present inven-
7 tion deals with this problem by providing a stabilizer
8 additive found effective in compatibilizing the composi-
g tions disclosed herein or enhancing ~he compatibility of
said components.
11 In accordance with the present invention, there
12 are provided storage stable lubricating oil compositions
13 having a reduced tendency to form sediment comprising:
14 (a) a polycarboxylic acid-glycol ester fric-
tion reducing component,
16 (b) an oil-soluble alkenyl succinimide or bor-
17 ated alkenyl succinimide dispersant, and
18 (c) an oil-soluble stabilizer additive being
19 a polyol or polyol anhydride partial ester
of a C8-C22 fatty acid or an ethoxylated
21 fatty acid, fatty amine or fatty amide, in
22 an amount effective to reduce the tendency
23 of said lubricating oil formulation to
24 form sediment.
Tha term lubricating oil composition as used
26 herein is meant to refer to fully formulated compositions
27 intended for use, for example as crankcase motor oils~
28 which contain a number of conventionally used additives
29 in the usual amounts especially oxidation inhibitors,
rust inhibitors, viscosity index improvers, such as ole-
1 fin copolymers, pour depressants, oil-soluble detergent
32 additives such as the neutral and basic metal phenates,
33 sulfurized phenates and sulfonates, such as the calcium
and magnesium sulfurized phenates and sulfonates,as well
as the zinc ~lkyl dithiophosph tes which are useful anti-oxidant
36 and anti-w~ additives. It is ~ ieve~ that the metal con-
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1 taining additi~es such as the normal and basic metal sul-
fonates, phenates and sulfurized phenates and metal di-
3 thiophosphates contribute to the tendency o~ lubricating
4 oil compositions to orm sediment when in the presence
of the ester friction reducing components and alkenyl suc-
6 cinimide dispersant. The metal phenates and sulfonates
7 noted above are typically employed in amounts of from
8 about 2 to 5 weight percent and metal dithiophosphates
9 are usually found in fully formulated lubricating oil com-
positions in amounts from about l to 3 weight percent.
ll The friction reducing esters are generally de-
12 rived from the esterification of a polycarboxylic acid
13 with a glycol and may be partial esters or diesters of
14 the ~ormulas:
lS HO-R'-OOC-R-COOH and HO-R ' -OOC-R-COOR" -OH
16 wherein R is the hydrocarbon radical of the acid and R'
17 and R" is either the hydrocarbon radical of an alkane
18 diol or the oxy-alkylene radical from an oxa-alkane diol
19 as defined hereinbelow. The polycarboxylic acid may be
an aliphatic saturated or unsaturated acid and will gen~
21 eralIy have a total of about 24 to 90, preferably about
22 24 to 60, carbon atoms and about 2 to 3, preferably about
23 2, carboxylic acid groups with at least about 9 carbon
24 atoms, preferably about 12 to 42, especially 16 to 22 car-
bon atoms between the carboxylic acid groups. Generally
26 about 1-3 moles of glycol, preferably 1-2 moles of glycol,
27 are used per mole of acid to pro~ide either a complete or
28 partial ester.
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29 Also, esters can be obtained by esteri~ying a
~30 dicarboxylic acid or mixture of such acids with a diol
1 or mixture of diols, in which case R would then be the
32 hydrocarbon radical of the dicarboxylic acid and R' and
R" would be the hydrocarbon radicals associated with the
diol or diols.
The friction reducing esters are typically used
6 in amounts ranging ~rom about 0.01 percent to 2 percent
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1 by weight, more preferably 0.05 to 0.5 percent by weight
2 based upon the overall weight of the lubricating oil com-
3 position, more preferably, formulations containing 0.1
4 to 0.3 weight percent are highly effective.
Especially preferred are the dimer acid ester
6 friction reducing esters. The term dimer acid used here-
7 in is meant to refer to those substituted cyclohexene di-
8 carboxylic acids formed by a Diels-Alder-type reaction
9 which is a thermal condensation of C18-C22 unsaturated
fatty acids, such as tall oil fatty acids, which ~ypical
11 ly contain about 85 to 90 percent oleic or linoleic acids.
12 Such dimer acids typically contain about 36 carbon atoms.
13 The dimer acid structure can be generalized as follows-
14
IRl
6 ~ ~ 2
18 iR ~ 3
19 4
with two of the R groups being carboxyl groups and two be-
21 ing hydrocarbon groups depending upon how the condensation
22 of the carboxylic acid has occurred. The car~oxyl grouE6
23 can be -(CH2)gCOOH;-CH=CH(CH2)8COOH;-(CH2)7COOX;
24 -CH2-CH=CH(CH217COOX;~CH=CH(CH2~7COOH and t~e h~drocarbon
25 terminating group can ~e represented b~: C~3(CH2)4-~;
26 (CH3(cH2)5-;cH3 ~CH2 ) 7-jCH3 (CH.2 ~ 4CH- CH - ; CH:3 ~CH2)4CH-CH-CH
27 and the like. The dimer o~ linoleic acid which is the
28 preerred embodiment can be exoressed in the ~ollowinq
2 9 formula:
31 (CH2)7COOH
32 [hfCH=CH (CH2) 7COOH
`f \ ( CH 2 ) 5CH 3
3 5 (CH2 ) 5CH3
36
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.. . . . .
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1 Also the term dimer acid as used herein neces-
2 sarily includes products containing up to about 24 per-
3 cent by weight trimer, but more typically about 10 per-
4 cent by weight trimer since, as is well known in the art,
5 the dimerization reaction provides a product containing
6 a trimer acid having molecular weight of about three times
7 the molecular weight to the starting fatty acid.
8 The polycarboxylic acids or dimer acids noted
9 above are esterified with a glycol, the glycol being an
10 alkane diol or oxa-alkane diol represented by the formula
~ O(~CHCH2O~xH wherein R i5 H or CH3 and x is about 2 to
12 100, preferably 2 to 25 with ethylene glycol and diethy-
13 lene glycol particularly preferred. A preferred embodi-
14 ment is formation of the ester with about 1 to 2 moles of
15 glycol per mole of dimer acid or polycarboxylic acid,
16 such as the ester of diethylene glycol with dimerized lin-
17 oleic acid.
18 The oil-soluble alkenyl succinimide ashless dis-
19 persants are those formed by reacting a polyalkenyl suc-
cinic acid or anhydride with a polyalkyleneamine. Pre-
21 ferably the alkenyl group-is derived from a polymer of a
22 C2 to C5 mono-olefin, especially a polyisobutylene where
23 the polyisobutenyl group has a number average molecular
24 weight of about 70Q to about 5,000, more preferably about
900 to 1,500. The polyamines may be represented by the
26 formula NH2(CH2)n-~NH(CH2)n)m-NH2 wherein n is 2 to 3 and
27 m is 0 to 10. Illustrative are ethylene diamine, diethy-
2~ lene triamine, triethylene tetramine, tetraethylene pent-
29 amine, which is preferred, pentaethylene hexamine and the
like, as well as mixtures of such polyamines. Theseamines
31 are reacted with the alkenyl succinic acid or anhydride in
32 ratios of about 1:1 to 10:1 moles of alkenyl succinic
33 acid or anhydride to polyamine.
34 The borated alkenyl succinimide dispersants are
also well known in the art as disclosed in U.S. Patent
36 3,254,025. These borated derivatives are provided by
37 treating the alkenyl succ~nimide with a boron compound
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1 selected from the class consisting of boron oxides, boron
2 halides, boron acids and esters thereof in an amount to
3 provide from about 0.1 atomic proportion of boron to about
4 10 atomic proportions of boron for each atomic proportion
of nitrogen in the dispersant. The borated product will
6 generally contain about 0.1 to 2.0, preferably 0.2 to 0O8
7 weight percent boron based upon ~he total weight of the
8 borated dispersant. The boron is considered to be present
9 as dehydrated boric acid polymers attaching as the metabor-
ate salt of the imide. The boration reaction is readily
11 carried out by adding from about 1 to 3 weight percent,
12 based on the weight of dispersant, of said boron compound,
13 preferably boric acid, to the dispersant as a slurry in
14 mineral oil and heating with stirring as from about 135C
to 165C for from 1 to 5 hours followed by ~itrogen strip-
16 ping and filtration of the product.
17 These alkenyl succinimide ashless dispersants and
18 borated derivatives thereof are used customarily in lubri-
19 cating oil compositions in amounts ranging from 0.7 to 10
percent, preferably 0.5 to 5 percent, by weight based upon
21 the total weight of the finished composition.
22 One category of the stabilizer additives of the
23 present invention may generally be defined as the polyol
24 ester of a C8-C22 fatty acid, partial ester meaning at
least one hydroxy group remains unreacted. Preferably 1
26 to 3 free OH groups are present such as an average of 1.5
27 to 2.5 free hydroxy groups. Such compounds are, per se,
28 known in the art and it is only their use as a stabilizing
29 agent in a formulated composition containing both the ester
friction modifier and alkenyl succinimide dispersant or
31 borated dispersant derivative thereof which is the basis
32 Of the present invention.
33 Suitable polyols for preparing the ester stabili-
34 zer of the present invention are those polyhydric alcohols
such as glycerol, diglycerol, and the sugar alcohols,
36 which may be represented in the formula CH2oH(cHoHlmcH2oH
37 where m is one t~ five as well as the polyol anhydrides
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1 thereof. Preferred are the esters of glycerol itself,
2 C3H5(O~)3, sorbitol and sorbitol anhydride (sorbitan).
3 Esters based upon relatively higher, i.e~, C12-C22, fatty
4 acids or mixtures of fatty acids are more preferable, such
5 as, the tall oil fatty acids. The fatty acids may be satu-
6 rated or unsaturated. Especially preferred are glycerol
7 and sorbitan parti~l esters of liquid C18-C22 unsaturated
8 fatty acids such as oleic, linoleic, and palmitoleic fat-
9 ty acids and mixtures of such acids.
Ethoxylated oil-soluble fatty acids, fatty acid
11 amines, and amides have also been found suitable for use
12 as sediment-reducing stabilizer additives in the composi-
]3 tions of the present invention. Useful products are those
14 oil-soluble ethoxylated additives of about C8 to C22 satu-
15 rated or unsaturated fatty acids, amines or amides. The
16 de~ree of ethoxylation of such products is about 2 to 30
17 moles, preferably 1 to 5 moles of ethylene oxide per mole
18 of fatty acid, amine or amide, so that the products retain
19 oil solubility. Derivatives of liquid unsaturated C12-C22
fatty acids are preferred, such as oleic, linoleic, pal-
21 mitoleic and mixtures thereof, such as the tall oil fatty
22 acids and vegetable oil fatty acids, for example, those
23 derived from cottonseed and soybean oils which contain
24 major amounts of unsaturated C18 fatty acids and which are
generally liquid at room temperature.
26 Of this category, the oil-soluble ethoxylated
27 fatty acid amines are a preferred embodiment including
28 both fatty acid monoamines and diamines, such as, oil-sol-
29 uble polyethoxylated (1-3 moles of ethylene oxide) coco-
amine derived from mixed coconut oil fatty acids (C12-C15)
31 and tallow diamine ethoxylates ~1-3 moles of ethylene
32 oxide) derived from mixtures of predominantly C16-C18 fatty
33 acids.
34 The quantity of sediment-reducing amount of ad-
ditive stabilizer of the present invention which is used
36 in a lubricating oil formulation is best expressed rela-
37 tive to the amount of the ester friction-reducing additive
'3 0 ~ '1
l which is present. The broad ratio is about 2 to 20 parts
2 bv weight of additive stabilizer per part by weight of
3 ester friction-reducing additive with the preferred ratio
4 being about 2 to 12 parts by weight of stabilizer additive
5 per part by weight of friction reducing ester.
6 While the method of addition of the stabilizer
7 additive is largely a function of the exact composition of
8 the total finished formulation, it is generally preferable
9 to provide a blend of stabilizer additive, friction-reduc-
ing ester and dispersant by admixing same at moderately
ll elevated temperatures, not greater than 150F, and incor-
12 porating this blend into the lubricating oil formulation
13 either prior to or subse~uent to the addition of other ad-
14 ditives in accordance with blending techniques known in
15 the art.
16 The lubricating oil base stock employed herein
17 are those customarily used: The term lubricating oil in-
18 cludes not only the petroleum hydrocarbon paraffinic,
l9 naphthenic, and aromatic oils of lubricating viscosity,but
20 also synthetic oils, such as, polyethylene oils, esters of
21 dicarboxylic acids, complex ester oils, polyglycol, and
22 alcohol alkyl esters of carbonic or phosphoric acids, poly-
23 silicones, fl ~ ohydrocar~on oils and the like. Preferred
24 base stocks are mineral hydrocarbon oils of a paraffinic
25 nature, especially those having a viscosity of about 20 to
26 100 cS min. (100F) and blends of such mineral paraffinic
27 oils.
28 The stabilizer additives of the present invention
29 are generally effective in substantially eliminating all
30 but traces of sediment when the lubricating oil formulation
31 contains the usually preferred amounts of friction reduc-
2 ing ester component, that is, about 0.05 to 0.3 weight per-
33 cent and ~herefore, formulations prepared in accordance
34 with the present invention which contain these amounts of
friction-reducing ester component are particularly pre-
36 ferred. For formulations containing more than about 0.3
37 weight percent of ester component, there will be in most
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1 cases a substantial reduction in the amount of sediment
2 observed after centrifuging as opposed to a complete eli-
3 mination to trace levels.
4 Examples 1-4
Lubricating oil formulations were prepared con-
6 taining the dimer acid ester friction modifier and the
7 alkenyl succinimide dispersant to which were added the
8 sediment-reducing additives of the present invention. ~he
9 formulation was a standard lOW~SAE quality automotive lub-
ricating oil composition con~aining a zinc dialkyl dithio-
11 phosphate, overbased metal sulfonate, rust inhibitor, and
12 VI improver in typical proportions. At this point the
13 formulation was storage stable with no evidence of sed~ent
14 formation. To this was added 0.1 percent by weight of a
15 friction modifier being the ester of a dimerized linoleic
16 acid and diethylene glycol and 5 weight percent of the re-
17 action product of 2.1 moles polyisobutenyl (Mn=1300) suc-
18 cinic anhydride (Sap. No. 103) and 1 mole of alkylene poly-
19 amine to provide the 3ase Formulation. The polyamine had
r~ 20 a composition approximating tetraethylene pentamine and
21 is available under the trade ~ "DOW E-100" from Dow
22 Chemical Company, Midland, Michigan. Samples (100 ml.,cali-
23 brated test tube) of this base formulation were centrifuged
24 for 8, 16 and 24 hours at 1900 r.p.m. at room temperature
25 and thereafter, samples containing the sediment reducing
26 additives of this invention were also tested for compat-
27 ibility by centrifuging under the same conditions. me volume
28 p~æ~ s~ment~asmeasured on the basis of the se~;ment obs~ved Ln
29 a calibrated test tube which contained the 100 ml. samples
30 and the results are set forth in the following Table I.
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1 TABLE I
2 V_l. % After Centrifu~ing
3 hrs. 16 hrsO 24 hrs.
5 Base .20 .50 3.00
6 Base + Glyceride Trace Trace Trace
7 (Example 1 and lA)
8 Base ~ Sor~itan Ester Trace Trace Trace
9 (Example 2)
10 sase + Ethoxylated - - Trace
11 Cocoamine
(Example 3)
12
13 Base + Ethoxylated - - Trace
Tallow Diamine
14 (Example 4)
Example 1: 0.26 weight percent liquid mixture
16 of mono- and diglyceride of oleic acid, 55 percent mono-
17 ester, 130 cps. viscosity at 25C, sold as ATMOS ~ 300
18 by ICI America, Inc.
19 Example lA: Example 1 was repeated using 0.56
weight percent of the same glyceride with the same results
21 after centrifuging.
22 Example 2: 1.25 weight perc nt Sorbitan Mono-
23 oleate li~uid having 1900 cps. at 25C viscosity sold as
24 Arlacel~ 80 by ICI America, Inc.
Example 3: 1.25 weight percent ethoxylated coco-
26 amine sold as Ethomeen~ C-12 by Armak, Inc., 2 moles ethyl-
27 ene oxide per mole amine, a~erage mol. weight = 285.
28 Example 4: 1.25 weight percent ethoxylated tal-
29 low diamine sold as Ethoduomeen~ TD-13 by Armak, Inc., 3
moles~ethylene oxideper mole amine, average mol. weight = 530.
31 Exam~le 5
32 A formulation was prepared similar to the base
33 Eormulation, the preceding Examples except that 0.3 weight
34 percent of the dimer acid ester friction reducing component
was used. The base formulation showed about a 3.0 vol.
36 percent sediment formation after 24 hours centrifuging.
~ 37 After addition of 1.25 weight percent of ~he same gly-
;: ~: : ` :
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l ceride of Example l,the formation was stable after 24
2 hours centrifuging,
3 Example 6
4 Example 5 was repeated with the same results
using the same stabilizer additive in the same amount ex-
6 cept that the base formulation contained a borated alkenyl
7 s~ccinimide dispersant prepared by reacting the dispersant
8 of the base formulation with a slurry of 1.4 moles of
g boric acid in mineral oil over a 3 hour period at 135
to 165C followed 4 hours of nitrogen stripping. The
ll final product contained l.S weight percent nitrogen and
12 0.3 weight percent boron and had a Mn of about 3,000.
.
