Field of the Invention
-
The present invention relates to an additive composition comprising in
combination an acylating agent substituted with a polymer of an alkene with 6 to 40
carbon atoms; and an acylating agent substituted with polyisobutylene. The
invention may be used in lubricating compositions especially for use in internal
combustion engines.
Background of the Invention
-
It is known to use dispersants in lubricating oils to disperse soot and decrease
the accumulation of sludge. Known dispersants include nitrogen containing
derivatives of polyisobutylene-substituted succinic acid and derivatives of
polydecene. Neither polyisobutylene-substituted succinic acid nor polydecene
derivatives exhibit both good low temperature and high temperature viscometrics.
-
Polyisobutylene-substituted succinic acid based dispersants provide good
dispersant properties at high temperature. However, at low temperature,
polyisobutylene succinic acid dispersants have poor viscometrics, causing lubricating
oils to thicken. To compensate for the poor low temperature viscometrics, viscosity
modifiers are added to lubricating oils. The presence of the viscosity modifiers can
lead to the potential for soot deposits and the accumulation of sludge.
-
Polydecene-based dispersants are known for good low temperature
viscometric properties, specifically kinematic viscosity and dynamic viscosity.
However, at high temperature polydecene-based dispersants are less effective than
polyisobutylene-substituted succinic acid based dispersants. Furthermore,
polydecene is less attractive as a commercial product due to relatively high costs
associated with its production.
-
GB Patent 1,439,567 discloses liquid organic compositions with detergent
properties by reacting a polymer of a straight chain 1-olefin having at least 10
carbons, with maleic anhydride to form the corresponding polyalkenyl succinic
anhydride. The polyalkenyl succinic anhydride is then reacted with an alkylene
polyamine to form the corresponding polyalkenyl succinimide.
-
US Patents 4,489,194 and 4,486,573 disclose compositions containing
hydrocarbyl substituted carboxylic acylating agents made by reacting, (A) one or
more alpha-beta olefinically unsaturated carboxylic acid reagents containing 2 to 20
carbon atoms, exclusive of the carboxyl-based groups with (B) one or more high
molecular weight olefin polymers of more than 30 carbon atoms selected from the
group consisting of (i) interpolymers of C2-8 mono-1-olefins with C12-C30 mono-olefins,
(ii) mixtures of (a) homopolymers and/or interpolymers of C2-8 mono-1-olefins
with (b) homopolymers and/or interpolymers of C12-C30 mono-olefins, and
(iii) chlorinated or brominated analogs of (i) or (ii). This invention includes the
acylated amine and/or alcohol derivatives of these hydrocarbyl-substituted
carboxylic acid acylating agents and their use in lubricants and normally liquid fuels.
-
PCT publication 99/46354 discloses the reaction products of maleic anhydride
and oligoalkenes obtained through oligomerisation of linear C8- to C12-1-alkenes.
The linear C8- to C12-1-alkenes contain vinylidene double bond fractions above 30%
and have a number average molecular weight from 1000 to 20,000.
-
It would be desirable to have a composition with dispersancy properties
including good high and low temperature viscometrics, capable of improving seal
compatability, capable of reducing the amount of volatile oils of lubricating viscosity
used and capable of decreasing the accumulation of sludge and/or soot deposits.
Summary of the Invention
-
The present invention provides a composition comprising:
- (a) an acylating agent containing a substituent of a polymer of an alkene having
about 6 to about 40 carbon atoms; and
- (b) an acylating agent containing a polyisobutylene substituent;
provided that the weight percent ratio of the alkene polymer substituent to the
polyisobutylene substituent in the composition is about 25:75 to about 75:25.
The invention further provides a composition comprising the reaction product of:
- (a) an acylating agent containing a substituent of a polymer of an alkene having
about 6 to about 40 carbon atoms; and
- (b) an acylating agent containing a polyisobutylene substituent; and
at least one compound selected from the group consisting of amines, alcohols,
aminoalcohols and mixtures thereof,
provided that the weight percent ratio of the alkene polymer substituent to the
polyisobutylene substituent in the composition is about 25:75 to about 75:25.
-
-
The invention further provides a composition comprising:
- (a) an acylating agent containing a substituent of a polymer of an alkene having
6 to 11 carbons atoms; and
- (b) an acylating agent containing a polyisobutylene substituent;
provided that the weight percent ratio of the polyalkene substituent to the
polyisobutylene substituent in the composition is about 5:95 to about 95:5. -
-
The invention further provides a method for preparing an acylating agent
composition, comprising reacting a carboxylic acid reactant with a mixture of an
alkene polymer of 6 to about 40 carbon atoms and a polyisobutylene, wherein the
weight ratios of the alkene polymer and the polyisobutylene employed are about
25:75 to about 75:25.
-
The invention further provides a method for preparing an acylating agent
composition, comprising reacting a carboxylic acid reactant with an alkene polymer
of 6 to about 40 carbon atoms, and separately reacting a carboxylic acid reactant with
a polyisobutylene, and subsequently combining the reaction products; wherein the
weight ratios of the alkene polymer and the polyisobutylene employed are about
25:75 to about 75:25.
-
The invention further provides a method for preparing a dispersant composition,
comprising mixing together:
- the reaction product of an acylating agent containing a substituent of a
polymer of an alkene having about 6 to about 40 carbon atoms with an amine,
alcohol, aminoalcohol, or mixtures thereof; and
- the reaction product of an acylating agent containing a polyisobutylene
substituent with an amine, alcohol, aminoalcohol, or mixtures thereof;
provided that the weight percent ratio of the alkene polymer substituent to the
polyisobutylene substituent in the composition is about 25:75 to about 75:25. -
-
The invention further provides a method for lubricating an internal
combustion engine, comprising supplying thereto a lubricant comprising the
composition as described herein.
-
The present invention further provides a composition capable of providing
good high temperature and low temperature viscometrics. It can further lead to a
decrease in sludge accumulation and soot deposits. It further provides compositions
capable of decreasing the amount of viscosity modifier in lubricating oils. It further
provides compositions capable of reducing the amount of volatile oils of lubricating
viscosity used and capable of imparting improved seal compatability.
Detailed Description of the Invention
-
In one aspect, the composition of the present invention comprises:
- (a) an acylating agent containing a substituent of a polymer of an alkene having
about 6 to about 40 carbon atoms; and
- (b) an acylating agent containing a polyisobutylene substituent;
provided that the weight percent ratio of the alkene polymer substituent to the
polyisobutylene substituent in the composition is about 25:75 to about 75:25. -
-
Preferably the weight percent ratio of alkene polymer to polyisobutylene ratio
is 30:70 to 70:30, more preferably 35:65 to 65:35, more preferably 40:60 to 60:40
and most preferably 45:55 to 55:45.
-
The alkene comprises carbon atoms ranging from a lower value of carbon
atoms of 6, 7, 8, 9 or 10; and an upper value of 40, 30, 20, 18, 16, 14 or 11 carbon
atoms, or any combinations of lower and higher values, e.g., 6-40, 6-20, 6-11, 8-40,
8-20, or 8-11.
-
In an alternative embodiment, the composition comprises:
- an acylating agent substituted with a polymer of an alkene having 6 to 11 carbons
atoms; and
- an acylating agent substituted with a polyisobutylene; provided that the weight percent
ratio of the alkene polymer to the polyisobutylene in the composition is 5:95 to 95:5.
-
-
Preferably the alkene polymer with 6 to 11 carbons atoms and the polyisobutylene
are present in a weight ratio of 10:90 to 90:10, more preferably, 20:80 to 80:20, more
preferably 25:75 to 75 to 25, even more preferably 30:70 to 70:30, even more preferably
35:65 to 65:35, even more preferably 40:60 to 60:40 and most preferably 45:55 to 55:45.
-
The polyalkene preferably contains a vinylidene double bond. Preferably the
fraction of polyalkene molecules containing the vinylidene double bond is at least
25%, more preferably at least 30%, even more preferably at least 45%, even more
preferably at least 55% and most preferably at least 70%.
-
Examples of suitable alkenes include monomers selected from the group
consisting of 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene,
1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene,
1-octadecene, 1-nonadecene, 1-eicosene, 1-henicosene, 1-docosene, 1-tetracosene, 1-pentacosene,
1-hexacosene, 1-octacosene, 1-nonacosene and mixtures thereof. A
preferred alkene is 1-decene.
-
Polyisobutylene is derived from isobutylene. It preferably contains a
vinylidene double bond. Preferably the fraction of polyisobutylene molecules
containing a vinylidene double bond is at least 25%, more preferably at least 30%,
even more preferably at least 45%, even more preferably at least 55% and most
preferably at least 70%.
-
The number average molecular weight of the substituents (a) and (b) of the
invention can be controlled using a variety of techniques such as reaction
temperature, initiators, monomer concentration and type of chain transfer agent. The
number average molecular weight of the substituents of each (a) and (b) is preferably
350 to 25,000, more preferably 500 to 15,000, and most preferably 1,000 to 5,000.
-
As used herein, the term "hydrocarbyl substituent" or "hydrocarbyl group" is
used in its ordinary sense, which is known to those skilled in the art. Specifically, it
refers to a group having a carbon atom directly attached to the remainder of the
molecule and having predominantly hydrocarbon character. Examples of hydrocarbyl
groups include:
- (1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl),
alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and
alicyclic-substituted aromatic substituents, as well as cyclic substituents wherein the
ring is completed through another portion of the molecule (e.g., two substituents
together form a ring);
- (2) substituted hydrocarbon substituents, that is, substituents containing non-hydrocarbon
groups which, in the context of this invention, do not alter the predominantly
hydrocarbon substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy,
mercapto, alkylmercapto, nitro, nitroso, and sulfoxy);
- (3) hetero substituents, that is, substituents which, while having a predominantly
hydrocarbon character, in the context of this invention, contain other than carbon in a ring
or chain otherwise composed of carbon atoms. Heteroatoms include sulphur, oxygen,
nitrogen, and encompass substituents as pyridyl, furyl, thienyl and imidazolyl. In general,
no more than two, preferably no more than one, non-hydrocarbon substituent will be
present for every ten carbon atoms in the hydrocarbyl group; typically, there will be no
non-hydrocarbon substituents in the hydrocarbyl group.
-
Acylating Agents
-
The acylating agents (which are substituted by the above-described polymers)
include monobasic or polybasic carboxylic acids or reactive equivalents thereof.
Reactive equivalents of carboxylic acids include anhydrides, esters, acylated
nitrogen, acyl halide, nitriles, metal salts or mixtures thereof. Among these,
anhydrides, particularly of diacids, are preferred.
Monobasic carboxylic acids include those represented by the formula:
wherein R
1 is hydrogen or hydrocarbyl containing 1 to 20, preferably 1 to 10, more
preferably 1 to 5 and most preferably 1 to 2 carbon atoms; and R
2 is hydrogen or
alkyl with 1 to 6, preferably 1 to 4 and most preferably 1 to 2 carbon atoms.
-
Monobasic carboxylic acids and derivatives thereof include (meth)acrylic
acid, cinnamic acid, crotonic acid, 3-phenylpropenoic acid, α,β-decenoic acid,
glyoxylic acid and mixtures thereof. (The expression "(meth)acrylic" is intended to
encompass both acrylic and methacrylic.)
-
Dibasic carboxylic acids and derivatives thereof include fumaric acid, maleic
acid, mesaconic acid, itaconic acid, and citraconic acid. In one embodiment the
derivative of a dibasic carboxylic acid is maleic anhydride.
-
In one embodiment the carboxylic acid includes glyoxylic acid or an ester
thereof, or the hemiacetals of any of them. A preferred class of glyoxylic acid
derivatives are glyoxylic acid esters. Examples of suitable glyoxylic acid esters
include methyl glyoxylate, ethyl glyoxylate, n-propyl glyoxylate, isopropyl
glyoxylate, n-butyl glyoxylate, isobutyl glyoxylate, pentyl glyoxylate, hexyl
glyoxylate, heptyl glyoxylate, octyl glyoxylate, nonyl glyoxylate, decyl glyoxylate,
undecyl glyoxylate, dodecyl glyoxylate, tridecyl glyoxylate, tetradecyl glyoxylate,
pentadecyl glyoxylate, hexadecyl glyoxylate, heptadecyl glyoxylate, octadecyl
glyoxylate, nonadecyl glyoxylate, icosyl glyoxylate, stearyl glyoxylate, palmityl
glyoxylate, hemiacetal glyoxylate esters such as glyoxylic methanol ester
hemiacetals and mixtures thereof.
-
Preferred acylating agents are selected from the group consisting of maleic acid,
maleic anhydride, (meth) acrylic acid, itaconic acid, fumaric acid, glyoxylic acid and
mixtures thereof.
-
In one aspect of the present invention the composition comprises the reaction
product of:
- (a) an acylating agent containing a substituent of a polymer of an alkene
having about 6 to about 40 carbon atoms; and
- (b) an acylating agent containing a polyisobutylene substituent; and
- (c) at least one compound selected from the group consisting of amines,
alcohols, aminoalcohols and mixtures thereof,
provided that the weight percent ratio of the alkene polymer substituent to the
polyisobutylene substituent in the composition is about 25:75 to about 75:25 -
Process
-
The compositions of the invention can be prepared using the following
methods:
- (I) For preparing an acylating agent composition, reacting a carboxylic acid
reactant with a mixture of an alkene polymer of 6 to about 40 carbon atoms and a
polyisobutylene, wherein the weight ratios of the alkene polymer and the
polyisobutylene employed are about 25:75 to about 75:25.
- (II) For preparing an acylating agent composition, reacting a
carboxylic acid reactant with an alkene polymer of 6 to about 40 carbon atoms, and
separately reacting a carboxylic acid reactant with a polyisobutylene, and
subsequently combining the reaction products; wherein the weight ratios of the
alkene polymer and the polyisobutylene employed are about 25:75 to about 75:25
- (III) For preparing a dispersant composition, mixing together:
- the reaction product of an acylating agent containing a substituent of a polymer of an
alkene having about 6 to about 40 carbon atoms with an amine, alcohol,
aminoalcohol, or mixtures thereof; and
- the reaction product of an acylating agent containing a polyisobutylene substituent
with an amine, alcohol, aminoalcohol, or mixtures thereof;
- provided that the weight percent ratio of the alkene polymer substituent to the
polyisobutylene substituent in the composition is about 25:75 to about 75:25.
The methods (I), (II) and (III) are typically conducted in the temperature
range of 100°C to 300°C, preferably 130°C to 270°C and more preferably 150°C to
250°C.In one embodiment, the methods (I) and (II) may contain a halogen selected
from the group consisting of chlorine, bromine, iodine and mixtures thereof. The
reactions carried out in the presence of halogen can take place in the temperature
range of 100°C to 300°C, preferably 110°C to 250°C and more preferably 120°C to
220°C. - (IV) The invention further includes a method for reacting (I) or (II) with
compounds selected from the group consisting of amines, alcohols, aminoalcohols
and mixtures thereof. The resulting product has dispersant properties.
-
Reaction Products with Amines, Alcohols and Aminoalcohols
-
Amines suitable for reacting with the mixture (a) and (b) include monoamines
and polyamines, preferably polyamines. The polyamines may be linear or branched
and are selected from the group consisting of alkylenepolyamine, cycloaliphatic
polyamine, heterocyclic polyamines and mixtures thereof.
-
In one embodiment the alkylenepolyamines are selected from the group
consisting of ethylenepolyamines, propylenepolyamines, butylenepolyamines and
mixtures thereof. Examples of propylenepolyamines include propylenediamine,
dipropylenetriamine or mixtures thereof. Ethylenepolyamines are preferred and
specific compounds include ethylenediamine, diethylenetriamine, triethylenetetramine,
tetraethylenepentamine, pentaethylenehexamine, polyamine still bottoms
and so-called "heavy amines" such as HPA-X™ from Union Carbide and E-100™
from Dow, and mixtures thereof.
-
In one embodiment the polyamines are α,β-diaminoalkanes. Suitable α,β-diaminoalkanes
include diaminopropanes, diaminobutanes or mixtures thereof.
Specific diaminoalkanes are selected from the group consisting of N-(2-aminoethyl)-1,3-propane
diamine, 3,3'-diamine-N-methyldipropylamine, tris(2-amino-ethyl)amine,
N,N-bis(3-aminopropyl)-1,3-propane diamine, N,N'-1,2-ethanediylbis-(1,3-propane
diamine) and mixtures thereof.
-
Other suitable polyamines include di-(trimethylene)triamine, piperazine,
diaminocyclohexanes and mixtures thereof.
-
Alcohols suitable for reacting with the mixture (a) and (b) include
monohydric and polyhydric alcohols. Polyhydric alcohols are preferred with 2 to 10,
preferably 2 to 6 hydroxy groups. The alcohols can be aliphatic, cycloaliphatic,
aromatic, or heterocyclic.
-
Suitable alcohols include dihydroxypropanes, dihydroxybutanes, dihydroxy-pentanes,
glycerine, trihydroxypropanes, trihydroxybutanes, trihydroxypentanes and
mixtures thereof.
-
In one embodiment the preferred alcohol is a polyol. Suitable polyols include
ethylene glycol, propylene glycol, butylene glycol, pentaerthyritol, mannitol,
sorbitol, glycerol, erythritol, 2-hydroxymethyl-2-methyl-1,3-propanediol
(trimethylolethane), 2-ethyl-2-(hydroxymethyl)-1,3-propanediol
(trimethylolpropane), 1,2,4-hexanetriol and mixtures thereof.
-
Aminoalcohols suitable for the invention contain 1 to 6 and preferably 1 to 3
hydroxy groups; and 1 to 8 and preferably 1 to 2 amine groups.
-
The aminoalcohols of the invention can be selected from the group consisting
of ethanolamine, isopropanolamine, diethanolamine, triethanolamine, diethylethanolamine,
dimethylethanolamine, dibutylethanolamine, 3-amino-1,2-propanediol;
serinol; 2-amino-2-methyl-1,3-propanediol; tris(hydroxymethyl)-aminomethane; 1-amino-1-deoxy-D-sorbitol;
diethanol amine; diisopropanolamine; N-methyl-N,N-diethanol
amine; triethanolamine; N,N,N',N'-tetrakis(2-hydroxypropyl)ethylene-diamine,
2-amino-2-methyl-1-propanol, 2-dimethylamino-methyl-1-propanediol, 2-amino-2-ethyl-1,3-propanediol,
2-amino-2-methyl-1,3-propanediol, 2-amino-1-butanol
and mixtures thereof. Preferably the aminoalcohol is ethanolamine.
Oil of Lubricating Viscosity
-
The composition of the present invention can be added to an oil of lubricating
viscosity. Such oils include natural and synthetic oils, oil derived from
hydrocracking, hydrogenation, hydrofinishing, unrefined, refined and re-refined oils,
and mixtures thereof.
-
Unrefined oils are those obtained directly from a natural or synthetic source
generally without (or with little) further purification treatment.
-
Refined oils are similar to the unrefined oils except they have been further
treated in one or more purification steps to improve one or more properties.
Purification techniques are known in the art and include solvent extraction,
secondary distillation, acid or base extraction, filtration, percolation and the like.
-
Re-refined oils are also known as reclaimed or reprocessed oils, and are
obtained by processes similar to those used to obtain refined oils and often are
additionally processed by techniques directed to removal of spent additives and oil
breakdown products.
-
Natural oils useful in making the inventive lubricants include animal oils,
vegetable oils (e.g., castor oil, lard oil), mineral lubricating oils such as liquid
petroleum oils and solvent-treated or acid-treated mineral lubricating oils of the
paraffinic, naphthenic or mixed paraffinic-naphthenic types and oils derived from
coal or shale or mixtures thereof.
-
Synthetic lubricating oils are useful and include hydrocarbon oils such as
polymerised and interpolymerised olefins (e.g., polybutylenes, polypropylenes,
propyleneisobutylene copolymers); poly(1-hexenes), poly(1-octenes), poly(1-decenes),
and mixtures thereof; alkyl-benzenes (e.g. dodecylbenzenes,
tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-benzenes); polyphenyls (e.g.,
biphenyls, terphenyls, alkylated polyphenyls); alkylated diphenyl ethers and
alkylated diphenyl sulphides and the derivatives, analogs and homologs thereof and
mixtures thereof. Polyalphaolefins are typically hydrogenated when used as
lubricating oils.
-
Other synthetic lubricating oils include but are not limited to liquid esters of
phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, and the
diethyl ester of decane phosphonic acid), and polymeric tetrahydrofurans. Synthetic
oils may be produced by Fischer-Tropsch reactions and typically may be
hydroisomerised Fischer-Tropsch hydrocarbons or waxes.
-
Oils of lubricating viscosity can also be defined as specified in the American
Petroleum Institute (API) Base Oil Interchangeability Guidelines. The five base oil
groups are as follows: Group I (sulphur content >0.03 wt %, and/or <90 wt %
saturates, viscosity index 80-120); Group II (sulphur content ≤0.03 wt %, and ≥90 wt
% saturates, viscosity index 80-120); Group III (sulphur content ≤0.03 wt %, and
≥90 wt % saturates, viscosity index ≥120); Group IV (all polyalphaolefins (PAOs));
and Group V (all others not included in Groups I, II, III, or IV). Preferably the oil of
lubricating viscosity is selected from an API Group II, Group III, Group IV, Group V
oil and mixtures thereof.
-
The oil of lubricating viscosity is typically present at 30 to 99.9, preferably 55
to 99, and more preferably 65 to 96 and most preferably 73 to 95 weight percent of
the lubricating oil composition.
-
In a typical lubricating composition comprising, the compositions of the
invention can be present in an oil of lubricating viscosity in amounts of 0.1 to 30,
preferably 0.5 to 20, more preferably 1 to 15, and most preferably 5 to 12 weight
percent of the lubricating oil composition.
-
If the present invention is in the form of a concentrate (which can be combined
with additional oil to form, in whole or in part, a finished lubricant), the ratio of each
of the above-mentioned dispersant, as well as other components, to diluent oil is
typically in the range of 99:1 to 10:90 by weight.
Optional Additives
-
Optionally the lubricating composition can include additives selected from the
group consisting of antioxidants, metal deactivators, detergents, antiwear agents,
dispersants, antiscuffing agents, extreme pressure agents, foam inhibitors,
demulsifiers, viscosity modifiers, pour point depressants and mixtures thereof.
-
The total combined amount of the optional additives present can be 0 to 40,
preferably 0.5 to 25, more preferably 3 to 20 and most preferably 5 to 15 weight
percent of the lubricating oil composition.
Antioxidants
-
Antioxidants include hindered phenols represented by the formula:
wherein R
3 and R
4 are independently branched or linear alkyl groups containing
about 1 to 24, preferably 4 to 18, and most preferably 4 to 12 carbon atoms. R
3 and
R
4 can be either straight or branched chain; branched is preferred. Preferably the
phenol is butyl substituted containing two t-butyl groups. When the t-butyl groups
occupy the 2,6-positions, the phenol is sterically hindered. Q is hydrogen or
hydrocarbyl. Examples of suitable hydrocarbyl groups include 2-ethylhexyl, n-butyl,
dodecyl or mixtures thereof.
-
Other optional sterically hindered phenols suitable for the invention include
those represented by the formulae:
wherein R
5, R
6, R
7, R
8, R
9, R
10 are either straight or branched chain and contain 4 to
18, preferably 4 to 12 carbon atoms. Preferably the phenol is butyl substituted. R
11
and R
12 are independently hydrogen or hydrocarbyl; preferably R
11 and R
12 are
arylalkyl or alkyl groups. The alkyl groups can be linear or branched, linear being
preferred. R
11 and R
12 are preferably in the para position. The arylalkyl or alkyl
groups typically contain 1 to 15, preferably 1 to 10, and more preferably 1 to 5
carbon atoms. The bridging group Y includes -CH
2- (methylene bridge) or
-CH
2OCH
2- (ether bridge).
-
Examples of methylene-bridged sterically hindered phenols include 4,4'-methylene-bis-(6-tert-butyl
o-cresol), 4,4 -methylene-bis-(2-tert-amyl-o-cresol), 2,2'-methylene-bis-(4-methyl-6-tert-butylphenol),
4,4-methylene-bis-(2,6-di-tertbutyl-phenol)
and mixtures thereof.
-
In one embodiment the antioxidant is a hindered ester-substituted phenol
represented by the formula:
wherein R
13, R
14 and R
15 are straight or branched alkyl group containing 2 to 22,
preferably 2 to 18, more preferably 4 to 8 carbon atoms. Specific examples include
of alkyl groups include 2-ethylhexyl or n-butyl ester, dodecyl and mixtures thereof.
-
Another class of antioxidant is alkylated diphenylamines that can be
represented by the following formula:
wherein R
16 and R
17 are independently hydrogen or hydrocarbyl, preferably
arylalkyl or alkyl groups. The arylalkyl groups contain 5 to 20, preferably 6 to 10
carbons atoms. The alkyl groups can be linear or branched, preferably linear; the
alkyl group contains 1 to 24, preferably 2 to 18 and most preferably 4 to 12 carbon
atoms; and z is independently 0, 1, 2, or 3, provided that at least one aromatic ring
contains a hydrocarbyl group. Preferred alkylated diphenylamines include bis-nonylated
diphenylamine and bis-octylated diphenylamine and mixtures thereof.
Metal Deactivators
-
Metal deactivators can be used to neutralise the catalytic effect of metal for
promoting oxidation in lubricating oil. Examples of metal deactivators include
derivatives of benzotriazoles, benzimidazoles, 2-alkyldithiobenzimidazoles, 2-alkyl-dithiobenzothiazoles,
2-(N,N-dialkyldithiocarbamoyl)benzothiazoles, 2,5-bis(alkyl-dithio)-1,3,4-thiadiazoles,
2,5-bis(N,N-dialkyldithiocarbamoyl)-1,3,4-thiadiazoles, 2-alkyldithio-5-mercapto
thiadiazoles and mixtures thereof.
-
Preferably the metal deactivator is a hydrocarbyl substituted benzotriazole
compound. The benzotriazole compounds can include hydrocarbyl substitutions in at
least one of the following ring positions 1- or 2- or 4- or 5- or 6- or 7-. The
hydrocarbyl groups contain about 1 to about 30, preferably about 1 to about 15, more
preferably about 1 to about 7 carbon atoms, most preferably the metal deactivator is
5-methylbenzotriazole, which may be used alone or in combination.
Detergents
-
Detergents are well-known and include neutral or overbased, carbonated or
non-carbonated Newtonian or non-Newtonian, basic salts of alkali, alkaline earth and
transition metals with one or more hydrocarbyl sulphonic acid, carboxylic acid,
phosphorus acid, mono- and/or di- thiophosphorus acid, alkyl phenol, sulphur
coupled alkyl phenol compounds, salixarates, saligenins or mixtures thereof.
Commonly used metals are sodium, potassium, calcium, magnesium, lithium or
mixtures thereof. Most commonly used metals include sodium, magnesium, calcium
and mixtures thereof. Overbased detergents are disclosed for instance in US Patent
3,629,109.
Dispersants
-
Dispersants are often known as ashless-type dispersants because, prior to mixing in
a lubricating oil composition, they do not contain ash-forming metals; and they do not
normally contribute any ash forming metals when added to a lubricant. Ashless type
dispersants are characterised by a polar group attached to a relatively high molecular
weight hydrocarbon chain. Typical ashless dispersants include N-substituted long chain
alkenyl succinimides. Examples of N-substituted long chain alkenyl succinimides include
polyisobutylene succinimide with number average molecular weight in the range 350 to
5000, preferably 500 to 3000. Succinimide dispersants and their preparation are disclosed,
for instance, in US Patent 4,234,435.
Antiwear Agents
-
The lubricant may additionally contain an antiwear agent. Useful antiwear
agents include metal thiophosphates, especially zinc dialkyldithiophosphates;
phosphoric acid esters or salt thereof; phosphites; and phosphorus-containing
carboxylic esters, ethers, and amides.
Antiscuffing Agents
-
The lubricant may also contain an antiscuffing agent. Antiscuffing agents that
decrease adhesive wear are often sulphur containing compounds. Typically the
sulphur containing compounds include organic sulphides and polysulphides, such as
benzyldisulphide, bis-(chlorobenzyl) disulphide, dibutyl tetrasulphide, di-tertiary
butyl polysulphide, sulphurised sperm oil, sulphurised methyl ester of oleic acid,
sulphurised alkylphenol, sulphurised dipentene, sulphurised terpene, sulphurised
Diels-Alder adducts, alkyl sulphenyl N'N-dialkyl dithiocarbamates, the reaction
product of polyamines with polybasic acid esters, chlorobutyl esters of 2,3-dibromo-propoxyisobutyric
acid, acetoxymethyl esters of dialkyl dithiocarbamic acid and
acyloxyalkyl ethers of xanthogenic acids or mixtures thereof.
Extreme Pressure Agents
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Extreme Pressure (EP) agents that are soluble in the oil include sulphur and
chlorosulphur-containing EP agents, chlorinated hydrocarbon EP agents, phosphorus
EP agents, and mixtures thereof. Examples of such EP agents include compounds
selected from the group consisting of chlorinated wax, organic sulphides and
polysulphides, such as benzyldisulphide, bis-(chlorobenzyl) disulphide, dibutyl
tetrasulphide, sulphurised sperm oil, sulphurised methyl ester of oleic acid,
sulphurised alkylphenol, sulphurised dipentene, sulphurised terpene, and sulphurised
Diels-Alder adducts; phosphosulphurised hydrocarbons, such as the reaction product
of phosphorus sulphide with turpentine or methyl oleate, phosphorus esters such as
the dihydrocarbon and trihydrocarbon phosphites, e.g., dibutyl phosphite, diheptyl
phosphite, dicyclohexyl phosphite, pentylphenyl phosphite; dipentylphenyl
phosphite, tridecyl phosphite, distearyl phosphite and polypropylene substituted
phenol phosphite, metal thiocarbamates, such as zinc dioctyldithiocarbamate and
barium heptylphenol diacid, such as zinc dicyclohexyl phosphorodithioate and the
zinc salts of a phosphorodithioic acid; amine salts of alkyl and dialkylphosphoric acids,
including, for example, the amine salt of the reaction product of a dialkyldithiophosphoric
acid with propylene oxide; and mixtures thereof.
Foam Inhibitors
-
Foam inhibitors are known and include organic silicones such as polyacetates,
dimethyl silicone, polysiloxanes, polyacrylates or mixtures thereof. Examples of
foam inhibitors include polyethylacrylate, poly-2-ethylhexylacrylate, polyvinylacetate
and mixtures thereof.
Demulsifiers
-
Demulsifiers are known and include derivatives of propylene oxide, ethylene
oxide, polyoxyalkylene alcohols, alkyl amines, amino alcohols, diamines or
polyamines reacted sequentially with ethylene oxide or substituted ethylene oxides or
mixtures thereof. Examples of demulsifiers include polyethylene glycols,
poly(ethyleneoxides), poly(propylene oxides), (ethylene oxide-propylene oxide)
polymers and mixtures thereof.
Pour Point Depressants
-
Pour point depressants are known and include esters of maleic anhydride-styrene
copolymers, polymethacrylates; polyacrylates; polyacrylamides;
condensation products of haloparaffin waxes and aromatic compounds; vinyl
carboxylate polymers; and terpolymers of dialkylfumarates, vinyl esters of fatty
acids, ethylene-vinyl acetate copolymers, alkyl phenol formaldehyde condensation
resins, alkyl vinyl ethers and mixtures thereof.
Viscosity Modifiers
-
Viscosity modifiers are known and include copolymers of styrene-butadiene
rubbers, ethylene-propylene polymers, polyisobutenes, hydrogenated styreneisoprene
polymers, hydrogenated radical isoprene polymers, polymethacrylate acid
esters, polyacrylate acid esters, polyalkyl styrenes, alkenyl aryl conjugated diene
copolymers, polyolefins, polyalkylmethacrylates, esters of maleic anhydride-styrene
copolymers or mixtures thereof.
Industrial Application
-
The compositions of the present invention are useful as additives in greases,
gear oils, industrial fluids, hydraulic fluids, transmission fluids, turbine oils,
circulating oils, and engine oils. They are particularly useful in lubricants for
internal combustion engines, such as diesel fuelled engines or gasoline fuelled
engines. Such engines can be lubricated by supplying thereto a lubricating oil
composition comprising the components as described above.
-
The use of the lubricating oil compositions of the invention in internal
combustion engines will typically exhibit at least one improved property selected
from the group consisting of good high temperature viscometrics, low temperature
viscometrics, decrease in sludge accumulation, decrease in soot deposits, improved
seal compatability, reduced amount of volatile oils of lubricating viscosity and a
decrease in amount of viscosity modifier required, and improved seal compatability.
Improved seal compatibility can be revealed by improved tensile strength, improved
elongation strength and decreased hardness.
-
The following examples provide an illustration of the invention. These
examples are non exhaustive and are not intended to limit the scope of the invention.
Examples
Examples 1 to 3 and Reference Examples R1 and R2
-
Mixtures of polydecene (obtained from BP Amoco) with number average
molecular weight of 1656 and high vinylidene polyisobutylene with number average
molecular weight of 1510 are reacted with maleic anhydride. The mixtures of high
vinylidene polydecene and high vinylidene polyisobutylene contain approximately
1600g of sample with weight ratios of polydecene: polyisobutylene of 1600:0,
1200:400, 800:800, 400:1200 and 0:1600 and are reacted with approximately 213.9g
of maleic anhydride. The reactants are heated to 203°C over 3 1/2 hours and held at
this temperature for twenty-four hours. The product of the reaction is then heated to
210°C for one hour under vacuum at 0.67 kPa (5mm Hg) to remove volatiles.
-
Approximately 600g of the above reaction product is dissolved in diluent oil
and heated to 110°C under nitrogen. Approximately 34g of HPAX™(polyamine still
bottoms) is added over 30 minutes and the reaction mixture is held at 110°C for a
further 30 minutes. The reaction is heated to 155°C and held for 5 hours. The
resulting product is cooled and filtered to produce a dispersant.
-
The dispersant is dissolved in a 5W-30 lubricating oil prepared containing
68.9 weight percent of Yubase™ 3050 API Group 3 base oil, 5 mm2s-1 (cSt) at 100°C
and 31.1 weight percent of PAO-6 Group 4 base oil, 6 mm2s-1 (cSt) at 100°C.
Reference examples 1 and 2 contain 100wt % of polyisobutylene succinimide and
100wt % of polydecene succinimide respectively. Examples 1 to 3 contain
polyisobutylene succinimide: polydecene succinimide weight percent ratios of 25:75,
50:50 and 75:25 respectively.
Examples 4 to 6 and Reference Examples R3 and R4
-
These samples are prepared in a similar process to examples 1 to 3 and
reference examples R1 to R2 except they are dissolved in Exxon 100N base oil at 0.5
wt%.
Examples 7 to 10 and Reference Examples R5 to R8
-
These samples are prepared in a similar process to example 5 except, 7 to 10
wt% of lubricating oil composition contains a 50:50 mixture of the polyisobutylene:
polydecene dispersant. Reference examples R5 to R8 contain 7 to 10 wt% of a
polyisobutylene dispersant in 5W-30 grade lubricating oil compositions containing
56 weight percent of API Group 4, PAO-4 base oil, 4 mm2s-1 (cSt) at 100°C, 30
weight percent of API Group 4, PAO-6 base oil, 6 mm2s-1 (cSt) at 100°C and 13.6
weight percent of PL 3970 API Group 5 base oil, 4.5 mm2s-1 (cSt) at 100°C.
Test 1: Seal Performance
-
Seal compatibility tests are designed to evaluate the effect of motor oils on
Parker-Pradifa™ FKM E-281 seal elastomers (fluoroelastomer). Six dumbbells of
elastomer are suspended using a micro wire and glass separators are covered by at
least 10 ml of oil. The test vessel is covered with aluminium foil and stored at 150°C
for 96 hours. The elastomer is removed from the oil and tested for percentage
change in tensile strength, elongation at break, cracking (by bending) and hardness.
The results obtained for examples 1 to 3 and comparative examples 1 and 2 are:
Ex. | Mixture | Final Seal Test Values |
| Wt % Polydecene | Wt% Polyisobutylene | Cracking | Tensile | Elongation (%) | Hardness (%) |
R1 | 0 | 100 | Mild | 8.1 | 170.0 | 71.0 |
1 | 25 | 75 | None | 8.5 | 172.2 | 71.0 |
2 | 50 | 50 | Barely | 10.0 | 206.6 | 70.5 |
3 | 75 | 25 | Barely | 8.2 | 175.6 | 71.0 |
R2 | 100 | 0 | Moderate | 7.8 | 168.8 | 72.2 |
The analysis indicates seals treated with compositions containing a weight percent
ratio of polydecene to polyisobutylene 25:75 to 75:25 have decreased amounts of
cracking compared with comparative examples 1 and 2. Furthermore, other seal
properties such as tensile strength, elongation and hardness are improved when
compositions containing a weight percent ratio of polydecene to polyisobutylene
25:75 to 75:25 are used. Overall the analysis indicates dispersants of the invention
provide improved seal properties compared with conventional dispersants.
Test 2: Sludge Performance
-
A dispersant sample is dissolved in Exxon 100N diluent oil at six
concentrations between 0.125 wt% and 0.004 wt% and mixed with a sludge sample.
The resulting mixture is allowed to stand for 24 hours. The amount of sludge
remaining in solution at the lowest concentration of dispersant is measured.
-
The sludge ratio is calculated by dividing the amount of sludge by the weight
percent of the dispersant used. The higher the sludge ratio indicates a lower
concentration of dispersant is better able to keep the sludge in solution. The results
obtained for examples 1 to 3 and comparative examples 1 and 2 are:
Example | Mixture | Sludge Ratio |
| Wt % Polydecene | Wt % Polyisobutylene |
R3 | 0 | 100 | 225 |
4 | 25 | 75 | 225 |
5 | 50 | 50 | 175 |
6 | 75 | 25 | 125 |
R4 | 100 | 0 | 63 |
-
The analysis indicates compositions with weight percent ratios of polydecene
to polyisobutylene between 25:75 and 75:25 have good dispersancy properties.
Furthermore, better results are obtained when the polydecene to polyisobutylene is
between 25:75 and 50:50.
Test 3: High Temperature Viscometrics at Constant Treat Rates
-
The KV100 (kinematic viscosity) value is determined by measuring the time
for 40g of oil to flow under gravity through a calibrated glass capillary viscometer.
-
Examples 4-6 and comparative examples R3-R4 demonstrate the high
temperature viscometrics for compositions of the invention with a dispersant treat
rate held at 9wt %. The results obtained are:
Example | Mixture |
| Wt % Polydecene | Wt% Polyisobutylene | KV100°C |
R3 | 0 | 100 | 13.10 |
4 | 25 | 75 | 12.73 |
5 | 50 | 50 | 12.01 |
6 | 75 | 25 | 11.69 |
R4 | 100 | 0 | 11.01 |
-
The analysis indicates only examples with polydecene substituent in the
dispersant composition maintain KV100°C at 12.5 mm2s-1 (cSt) or less. By
interpolating the KV100°C data, approximately 31wt % of polydecene substituent is
required in dispersant compositions with a 9 wt% treat rate to maintain KV100°C at
12.5 mm2s-1 (cSt) or less.
Test 4: High Temperature Viscometrics at Varied Treat Rates
-
Experimental procedure is as is described in Test 3. The results obtained for
examples 7 to 10 and reference examples R5-R8 are:
Example | Wt % Dispersant | KV100°C |
R5 | 7 | 12.03 |
R6 | 8 | 12.63 |
R7 | 9 | 13.1 |
R8 | 10 | 13.68 |
7 | 7 | 11.13 |
8 | 8 | 11.69 |
9 | 9 | 12.01 |
10 | 10 | 12.44 |
-
The analysis indicates to keep the oil at a viscosity of 12.5 mm2s-1 (cSt) or
less, the maximum amount of polyisobutylene-only type dispersants (reference
examples R5-R8) that can be used is 7wt % (example R5). However, using
dispersant compositions of the invention with a wt % ratio of polyisobutylene:
polydecene of 50:50 allows the amount of dispersant to be increased to 10wt%
(example 9).
-
Each of the documents referred to above is incorporated herein by reference.
Except in the Examples, or where otherwise explicitly indicated, all numerical
quantities in this description specifying amounts of materials, reaction conditions,
molecular weights, number of carbon atoms, and the like are to be understood as
modified by the word "about." Unless otherwise indicated, each chemical or
composition referred to herein should be interpreted as being a commercial grade
material which may contain the isomers, by-products, derivatives, and other such
materials which are normally understood to be present in the commercial grade.
However, the amount of each chemical component is presented exclusive of any
solvent or diluent oil, which may be customarily present in the commercial material,
unless otherwise indicated. It is to be understood that the upper and lower amount,
range, and ratio limits set forth herein may be independently combined. Similarly,
the ranges and amounts for each element of the invention can be used together with
ranges or amounts for any of the other elements. As used herein, the expression
"consisting essentially of" permits the inclusion of substances that do not materially
affect the basic and novel characteristics of the composition under consideration.
-
While the invention has been explained, it is to be understood that various
modifications thereof will become apparent to those skilled in the art upon reading
the specification. Therefore, it is to be understood that the invention disclosed herein
is intended to cover such modifications as fall within the scope of the appended
claims.