U.S. patent application number 14/069419 was filed with the patent office on 2014-05-08 for marine engine lubrication.
This patent application is currently assigned to Infineum International Limited. The applicant listed for this patent is Infineum International Limited. Invention is credited to Helen Bishop, Agata Checinska, Robert J. Glass.
Application Number | 20140128301 14/069419 |
Document ID | / |
Family ID | 47143003 |
Filed Date | 2014-05-08 |
United States Patent
Application |
20140128301 |
Kind Code |
A1 |
Glass; Robert J. ; et
al. |
May 8, 2014 |
MARINE ENGINE LUBRICATION
Abstract
Two-stroke cross-head marine compression-ignited engine system
lubrication is effected by a composition comprising a major amount
of an oil of lubricating viscosity containing at least 50 mass % of
a basestock containing greater than or equal to 90% saturates and
less than or equal to 0.03% sulphur or a mixture thereof, and
respective minor amounts of an oil-soluble overbased metal alkyl
salicylate detergent and an oil-soluble polyalkenyl-substituted
carboxylic acid anhydride or an oil-soluble alkylated phenol. The
presence of the anhydride or the phenol improves asphaltene
dispersency in the lubricant.
Inventors: |
Glass; Robert J.; (Didcot,
GB) ; Bishop; Helen; (Oxford, GB) ; Checinska;
Agata; (Didcot, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Infineum International Limited |
Abingdon |
|
GB |
|
|
Assignee: |
Infineum International
Limited
Abingdon
GB
|
Family ID: |
47143003 |
Appl. No.: |
14/069419 |
Filed: |
November 1, 2013 |
Current U.S.
Class: |
508/306 ;
508/460 |
Current CPC
Class: |
C10N 2040/252 20200501;
C10N 2020/04 20130101; C10M 2207/129 20130101; C10M 2207/127
20130101; C10M 129/20 20130101; C10M 2207/023 20130101; C10M
169/045 20130101; C10N 2030/04 20130101; C10M 2205/22 20130101;
C10M 2227/09 20130101; C10M 129/76 20130101; C10M 2203/1025
20130101; C10M 2205/0285 20130101; C10M 2207/262 20130101; C10M
2207/262 20130101; C10N 2010/04 20130101; C10M 2203/1025 20130101;
C10N 2020/02 20130101; C10M 2203/1025 20130101; C10N 2020/02
20130101; C10M 2207/262 20130101; C10N 2010/04 20130101 |
Class at
Publication: |
508/306 ;
508/460 |
International
Class: |
C10M 129/76 20060101
C10M129/76; C10M 129/20 20060101 C10M129/20 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 2, 2012 |
EP |
12191060.8 |
Claims
1. A system lubricating oil composition for a two-stroke cross-head
marine compression-ignited engine, the composition having a TBN of
less than 18 and comprising, or being made by admixing: (A) an oil
of lubricating viscosity, in a major amount, containing 50 mass% or
more of a basestock containing greater than or equal to 90%
saturates and less than or equal to 0.03% sulphur, or a mixture
thereof; (B) an oil-soluble overbased metal alkyl salicylate
detergent, in a minor amount; and (C) in a minor amount, an
oil-soluble polyalkenyl-substituted carboxylic acid anhydride, the,
or at least one, polyalkenyl group being derived from a polyalkene
having a number average molecular weight of from 200 to 3,000, or
an oil-soluble alkylated phenol.
2. The system lubricating oil composition of claim 1 where the oil
of lubricating viscosity contains more than 60 mass % of a
basestock containing greater than or equal to 90% saturates and
less than or equal to 0.03% sulphur or a mixture thereof.
3. The system lubricating oil composition of claim 1 where the
basestock is a Group II, Group III or Group IV basestock.
4. The system lubricating oil composition of claim 1 where (B) is
C.sub.9 to C.sub.30 alkyl-substituted.
5. The system lubricating oil composition of claim 1 where the
polyalkenyl substituent in (C) has from 8 to 400 carbon atoms.
6. The system lubricating oil composition of claim 5 where the
polyalkenyl substituent in (C) has from 12 to 100 carbon atoms.
7. The system lubricating oil composition of claim 6 where the
polyalkenyl substituent in (C) has from 16 to 64 carbon atoms.
8. The system lubricating oil composition of claims 1 where the
polyalkenyl substituent in (C) has a number average molecular
weight of from 350 to 1000,
9. The system lubricating oil composition of claims 1 where the
polyalkenyl substituent in (C) has a number average molecular
weight of from 500 to 1000,
10. The system lubricating oil compositions of claim 1 where the
polyalkenyl-substituted carboxylic acid anhydride in (C) is a
succinic anhydride.
11. The system lubricating oil composition of claim 10 where (C) is
a polybutene succinic anhydride.
12. The system lubricating oil composition of claim 1 where (C) is
an oil-soluble alkylated phenol derived from cashew nut shell
liquid (CNSL)
13. The system lubricating oil composition of claim 12 where (C) is
a hydrogenated cardenol.
14. The system lubricating oil composition of claim 1 where (C) is
a predominantly C.sub.2 Friedel-Crafts alkylated phenol.
15. The system lubricating oil composition of claim 1, wherein the
TBN is more than 1.
16. The system lubricating oil composition of claim 15, wherein the
TBN is more than 3.
17. The system lubricating oil composition of claim 1, wherein the
TBN is more than 5.
18. The system lubricating oil composition of claim 1, wherein the
TBN is less than 10.
19. A method of providing system lubrication to a two-stroke
cross-head marine compression-ignited engine, which comprises
lubricating the crankcase of the engine with a system lubricating
oil composition of claim 1.
20. A combination of the crankcase of a two-stroke cross-head
marine compression-ignited engine and a system lubricating oil
composition of claim 1.
Description
FIELD OF THE INVENTION
[0001] This invention relates to system oil lubrication of a
two-stroke cross-head marine compression-ignited engine. This
invention relates to a system oil for a two-stroke cross-head
marine compression-ignited engine.
BACKGROUND OF THE INVENTION
[0002] Two-stroke marine diesel engines are compression-ignition
engines in which each piston rod is connected to the crankshaft by
a cross-head bearing. They are lubricated by two separate
lubricants: cylinder oil and system oil. The cylinder oil is a
`once-through` lubricant that is burnt in the combustion chamber,
excess cylinder oil being drained via the cylinder oil duct. The
crankcase of the engine is lubricated by the system oil which
lubricates the bearings and journals as well as cooling the piston
undercrown.
[0003] Due to the low stress placed upon it, the system oil is not
changed. It needs to be able to cope with contamination arising
from cylinder drain oil passing through the stuffing box; system
oils blended with Group I base oils are able to cope with this
contamination. However, higher saturate base oils (such as Group
II) have been shown to be detrimental in respect of asphaltene
dispersancy, which may deposit on the undercrown of the pistons and
on the crankcase. This constitutes a problem in devising system
lubricants that are blended with higher saturate base oils.
[0004] WO 2008/119936 A1 ('936) describes system lubrication and
mentions Group I and Group II basestocks for system oils. It also
describes use of calcium alkyl salicylate detergents soap in a
system oil. It does not, however, exemplify use of Group II
basestocks nor does it mention the above problem regarding Group II
basestocks.
SUMMARY OF THE INVENTION
[0005] The invention is concerned with ameliorating the above
problem by incorporating a polyalkenyl-substituted carboxylic acid
anhydride or an alkylated phenol in a salicylate-containing system
oil blended with a higher saturates basestock. Use of such
anhydrides or phenols is not described in '936. WO 2008/021737 A2
('737) describes use of such anhydrides in marine lubricants, but
does not mention system lubrication. It mentions salicylate
detergents but exemplifies only sulphonate/phenate detergents.
[0006] A first aspect of the invention is a system lubricating oil
composition (i.e. a system oil) for a two-stroke cross-head marine
compression-ignited engine, the composition having a TBN of less
than 18, preferably less than 15, preferably 5 to 9, and
comprising, or being made by admixing: [0007] (A) an oil of
lubricating viscosity, in a major amount, containing 50 mass% or
more of a basestock containing greater than or equal to 90%
saturates and less than or equal to 0.03% sulphur or a mixture
thereof; [0008] (B) an oil-soluble overbased metal alkyl salicylate
detergent, in a minor amount; and [0009] (C) in a minor amount, an
oil-soluble polyalkenyl-substituted carboxylic acid anhydride, the,
or at least one, polyalkenyl group being derived from a polyalkene
having a number average molecular weight of from 200 to 3,000, or
an oil-soluble alkylated phenol, preferably an oil-soluble
alkylated phenol derived from cashew nut shell liquid (CNSL).
[0010] A second aspect of the invention is a method of providing
system lubrication to a two-stroke cross-head marine
compression-ignited engine, which comprises lubricating the
crankcase of the engine with a system lubricating oil composition
of the first aspect of the invention.
[0011] A third aspect of the invention is a combination of the
crankcase of a two-stroke cross-head marine compression-ignited
engine and a system lubricating oil composition of the first aspect
of the invention.
[0012] A fourth aspect of the invention is the use of detergent (B)
as defined in the first aspect of the invention in combination with
a polyalkenyl-substituted carboxylic acid anhydride or alkylated
phenol (C) as defined in the first aspect of the invention in
respective minor amounts in a system lubricating oil composition
for a two-stroke cross-head marine compression-ignited engine,
which composition comprises an oil of lubricating viscosity in a
major amount and contains 50 mass % or more of a basestock
containing greater than or equal to 90% saturates and less than or
equal to 0.03% sulphur or a mixture thereof, to improve asphaltene
dispersancy during operation of the engine, fueled by a heavy fuel
oil, and its system lubrication by the composition, in comparison
with analogous operation when the same amount of (B) is used in the
absence of (C).
[0013] In this specification, the following words and expressions,
if and when used, have the meanings ascribed below: [0014] "active
ingredients" or "(a.i.)" refers to additive material that is not
diluent or solvent; [0015] "comprising" or any cognate word
specifies the presence of stated features, steps, or integers or
components, but does not preclude the presence or addition of one
or more other features, steps, integers, components or groups
thereof; the expressions "consists of" or "consists essentially of"
or cognates may be embraced within "comprises" or cognates, wherein
"consists essentially of" permits inclusion of substances not
materially affecting the characteristics of the composition to
which it applies; [0016] "major amount" means 50 mass % or more of
a composition; [0017] "minor amount" means less than 50 mass % of a
composition; [0018] "TBN" means total base number as measured by
ASTM D2896. Furthermore in this specification, if and when used:
[0019] "calcium content" is as measured by ASTM 4951; [0020]
"phosphorus content" is as measured by ASTM D5185; [0021]
"sulphated ash content" is as measured by ASTM D874; [0022]
"sulphur content" is as measured by ASTM D2622; [0023] "KV100"
means kinematic viscosity at 100.degree. C. as measured by ASTM
D445.
[0024] Also, it will be understood that various components used,
essential as well as optimal and customary, may react under
conditions of formulation, storage or use and that the invention
also provides the product obtainable or obtained as a result of any
such reaction.
[0025] Further, it is understood that any upper and lower quantity,
range and ratio limits set forth herein may be independently
combined.
DETAILED DESCRIPTION OF THE INVENTION
[0026] The features of the invention will now be discussed in more
detail below.
Oil of Lubricating Viscosity (A)
[0027] The lubricating oils may range in viscosity from light
distillate mineral oils to heavy lubricating oils. Generally, the
viscosity of the oil ranges from 2 to 40 mm.sup.2/sec, as measured
at 100.degree. C.
[0028] Natural oils include animal oils and vegetable oils (e.g.,
castor oil, lard oil); liquid petroleum oils and hydrorefined,
solvent-treated or acid-treated mineral oils of the paraffinic,
naphthenic and mixed paraffinic-naphthenic types. Oils of
lubricating viscosity derived from coal or shale also serve as
useful base oils.
[0029] Synthetic lubricating oils include hydrocarbon oils and
halo-substituted hydrocarbon oils such as polymerized and
interpolymerized olefins (e.g., polybutylenes, polypropylenes,
propylene-isobutylene copolymers, chlorinated polybutylenes,
poly(1-hexenes), poly(1-octenes), poly(1-decenes)); alkybenzenes
(e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes,
di(2-ethylhexyl)benzenes); polyphenyls (e.g., biphenyls,
terphenyls, alkylated polyphenols); and alkylated diphenyl ethers
and alkylated diphenyl sulphides and derivative, analogues and
homologues thereof.
[0030] Alkylene oxide polymers and interpolymers and derivatives
thereof where the terminal hydroxyl groups have been modified by
esterification, etherification, etc., constitute another class of
known synthetic lubricating oils. These are exemplified by
polyoxyalkylene polymers prepared by polymerization of ethylene
oxide or propylene oxide, and the alkyl and aryl ethers of
polyoxyalkylene polymers (e.g., methyl-polyiso-propylene glycol
ether having a molecular weight of 1000 or diphenyl ether of
poly-ethylene glycol having a molecular weight of 1000 to 1500);
and mono- and polycarboxylic esters thereof, for example, the
acetic acid esters, mixed C.sub.3-C.sub.8 fatty acid esters and
C.sub.13 oxo acid diester of tetraethylene glycol.
[0031] Another suitable class of synthetic lubricating oils
comprises the esters of dicarboxylic acids (e.g., phthalic acid,
succinic acid, alkyl succinic acids and alkenyl succinic acids,
maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric
acid, adipic acid, linoleic acid dimer, malonic acid, alkylmalonic
acids, alkenyl malonic acids) with a variety of alcohols (e.g.,
butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl
alcohol, ethylene glycol, diethylene glycol monoether, propylene
glycol). Specific examples of such esters includes dibutyl adipate,
di(2-ethylhexyl)sebacate, di-n-hexyl fumarate, dioctyl sebacate,
diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl
phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic
acid dimer, and the complex ester formed by reacting one mole of
sebacic acid with two moles of tetraethylene glycol and two moles
of 2-ethylhexanoic acid.
[0032] Esters useful as synthetic oils also include those made from
C.sub.5 to C.sub.12 monocarboxylic acids and polyols and polyol
esters such as neopentyl glycol, trimethylolpropane,
pentaerythritol, dipentaerythritol and tripentaerythritol.
[0033] Silicon-based oils such as the polyalkyl-, polyaryl-,
polyalkoxy- or polyaryloxysilicone oils and silicate oils comprise
another useful class of synthetic lubricants; such oils include
tetraethyl silicate, tetraisopropyl silicate,
tetra-(2-ethylhexyl)silicate,
tetra-(4-methyl-2-ethylhexyl)silicate,
tetra-(p-tert-butyl-phenyl)silicate,
hexa-(4-methyl-2-ethylhexyl)disiloxane, poly(methyl)siloxanes and
poly(methylphenyl)siloxanes. Other synthetic lubricating oils
include liquid esters of phosphorus-containing acids (e.g.,
tricresyl phosphate, trioctyl phosphate, diethyl ester of
decylphosphonic acid) and polymeric tetrahydrofurans.
[0034] Unrefined, refined and re-refined oils can be used in
lubricants of the present invention. Unrefined oils are those
obtained directly from a natural or synthetic source without
further purification treatment. For example, a shale oil obtained
directly from retorting operations; petroleum oil obtained directly
from distillation; or ester oil obtained directly from
esterification and used without further treatment, are unrefined
oils. Refined oils are similar to unrefined oils except that the
oil is further treated in one or more purification steps to improve
one or more properties. Many such purification techniques, such as
distillation, solvent extraction, acid or base extraction,
filtration and percolation, are known to those skilled in the art.
Re-refined oils are obtained by processes similar to those used to
provide refined oils but begin with oil that has already been used
in service. Such re-refined oils are also known as reclaimed or
reprocessed oils and are often subjected to additional processing
using techniques for removing spent additives and oil breakdown
products.
[0035] The American Petroleum Institute (API) publication "Engine
Oil Licensing and Certification System", Industry Services
Department, Fourteenth Edition, December 1996, Addendum 1, December
1998 categorizes base stocks as follows: [0036] (a) Group I base
stocks contain less than 90 percent saturates and/or greater than
0.03 percent sulphur and have a viscosity index greater than or
equal to 80 and less than 120 using the test methods specified in
Table E-1. [0037] (b) Group II base stocks contain greater than or
equal to 90 percent saturates and less than or equal to 0.03
percent sulphur and have a viscosity index greater than or equal to
80 and less than 120 using the test methods specified in Table E-1.
[0038] (c) Group III base stocks contain greater than or equal to
90 percent saturates and less than or equal to 0.03 percent sulphur
and have a viscosity index greater than or equal to 120 using the
test methods specified in Table E-1. [0039] (d) Group IV base
stocks are polyalphaolefins (PAO). [0040] (e) Group V base stocks
include all other base stocks not included in Group I, II, III, or
IV.
[0041] Analytical Methods for Base Stock are tabulated below:
TABLE-US-00001 TABLE E-1 PROPERTY TEST METHOD Saturates ASTM D 2007
Viscosity Index ASTM D 2270 Sulphur ASTM D 2622 ASTM D 4294 ASTM D
4927 ASTM D 3120
[0042] By way of example, the present invention embraces Group II,
Group III and Group IV basestocks and also basestocks derived from
hydrocarbons synthesised by the Fischer-Tropsch process. In the
Fischer-Tropsch process, synthesis gas containing carbon monoxide
and hydrogen (or `syngas`) is first generated and then converted to
hydrocarbons using a Fischer-Tropsch catalyst. These hydrocarbons
typically require further processing in order to be useful as a
base oil. For example, they may, by methods known in the art, be
hydroisomerized; hydrocracked and hydroisomerized; dewaxed; or
hydroisomerized and dewaxed. The syngas may, for example, be made
from gas such as natural gas or other gaseous hydrocarbons by steam
reforming, when the basestock may be referred to as gas-to-liquid
("GTL") base oil; or from gasification of biomass, when the
basestock may be referred to as biomass-to-liquid ("BTL" or "BMTL")
base oil; or from gasification of coal, when the basestock may be
referred to as coal-to-liquid ("CTL") base oil.
[0043] As stated, the oil of lubricating viscosity in this
invention contains 50 mass % or more of the defined basestock or a
mixture thereof. Preferably, it contains 60, such as 70, 80 or 90,
mass % or more of the defined basestock or a mixture thereof The
oil of lubricating viscosity may be substantially all the defined
basestock or a mixture thereof. The basestock may for example be a
Group II, Group III or Group IV basestock.
Metal Alkyl Salicylate Detergent (B)
[0044] A metal detergent is an additive based on so-called metal
"soaps", that is metal salts of acidic organic compounds, sometimes
referred to as surfactants. They generally comprise a polar head
with a long hydrophobic tail. Overbased metal detergents, which
comprise neutralized metal detergents as the outer layer of a metal
base (e.g. carbonate) micelle, may be provided by including large
amounts of metal base by reacting an excess of a metal base, such
as an oxide or hydroxide, with an acidic gas such as carbon
dioxide.
[0045] In the present invention, (B) is an overbased metal, such as
calcium, alkyl-substituted salicylate.
[0046] Such a detergent, where the metal is calcium, typically has
the structure shown:
##STR00001##
wherein R is a linear alkyl group. There may be more than one R
group attached to the benzene ring. The COO.sup.- group can be in
the ortho, meta or para position with respect to the hydroxyl
group; the ortho position is preferred. The R group can be in the
ortho, meta or para position with respect to the hydroxyl
group.
[0047] Salicylic acids are typically prepared by the carboxylation,
by the Kolbe-Schmitt process, of phenoxides, and in that case, will
generally be obtained (normally in a diluent) in admixture with
uncarboxylated phenol. Salicylic acids may be non-sulphurized or
sulphurized, and may be chemically modified and/or contain
additional substituents. Processes for sulphurizing an alkyl
salicylic acid are well known to those skilled in the art, and are
described, for example, in US 2007/0027057.
[0048] The alkyl groups advantageously contain 5 to 100, preferably
9 to 30, especially 14 to 24, carbon atoms.
[0049] The term "overbased" is generally used to describe metal
detergents in which the ratio of the number of equivalents of the
metal moiety to the number of equivalents of the acid moiety is
greater than one. The term `low-based` is used to describe metal
detergents in which the equivalent ratio of metal moiety to acid
moiety is greater than 1, and up to about 2.
[0050] By an "overbased calcium salt of surfactants" is meant an
overbased detergent in which the metal cations of the oil-insoluble
metal salt are essentially calcium cations. Small amounts of other
cations may be present in the oil-insoluble metal salt, but
typically at least 80, more typically at least 90, for example at
least 95, mole %, of the cations in the oil-insoluble metal salt,
are calcium ions. Cations other than calcium may be derived, for
example, from the use in the manufacture of the overbased detergent
of a surfactant salt in which the cation is a metal other than
calcium. Preferably, the metal salt of the surfactant is also
calcium.
[0051] Carbonated overbased metal detergents typically comprise
amorphous nanoparticles. Additionally, there are disclosures of
nanoparticulate materials comprising carbonate in the crystalline
calcite and vaterite forms.
[0052] The basicity of the detergents may be expressed as a total
base number (TBN). A total base number is the amount of acid needed
to neutralize all of the basicity of the overbased material. The
TBN may be measured using ASTM standard D2896 or an equivalent
procedure. The detergent may have a low TBN (i.e. a TBN of less
than 50), a medium TBN (i.e. a TBN of 50 to 150) or a high TBN
(i.e. a TBN of greater than 150, such as 150-500). The basicity may
also be expressed as basicity index (BI) which is the molar ratio
of total base to total soap in the overbased detergent.
[0053] The treat rate of additive (B) in the lubricating oil
composition may for example be in the range of 0.1 to 10,
preferably 0.5 to 9, more preferably 1 to 8, even more preferably
1-6, mass %.
Polyalkenyl-Substituted Carboxylic Acid Anhydride or Alkylated
Phenol (C)
[0054] The anhydride may be mono or polycarboxylic, preferably
dicarboxylic. The polyalkenyl group preferably has from 8 to 400,
such as 8 to 100, carbon atoms.
[0055] General formulae of exemplary anhydrides may be depicted
as
##STR00002##
[0056] where R.sup.1 represents a C.sub.8 to C.sub.100 branched or
linear polyalkenyl group:
[0057] The polyalkenyl moiety may have a number average molecular
weight of from 200 to 3000, preferably from 350 to 950.
[0058] Suitable hydrocarbons or polymers employed in the formation
of the anhydrides of the present invention to generate the
polyalkenyl moieties include homopolymers, interpolymers or lower
molecular weight hydrocarbons. One family of such polymers comprise
polymers of ethylene and/or at least one C.sub.3 to C.sub.28
alpha-olefin having the formula H.sub.2C.dbd.CHR.sup.1 wherein
R.sup.1 is straight or branched chain alkyl radical comprising 1 to
26 carbon atoms and wherein the polymer contains carbon-to-carbon
unsaturation, preferably a high degree of terminal ethenylidene
unsaturation. Preferably, such polymers comprise interpolymers of
ethylene and at least one alpha-olefin of the above formula,
wherein R.sup.1 is alkyl of from 1 to 18 carbon atoms, and more
preferably is alkyl of from 1 to 8 carbon atoms, and more
preferably still of from 1 to 2 carbon atoms. Therefore, useful
alpha-olefin monomers and comonomers include, for example,
propylene, butene-1, hexene-1, octene-1, 4-methylpentene-1,
decene-1, dodecene-1, tridecene-1, tetradecene-1, pentadecene-1,
hexadecene-1, heptadecene-1, octadecene-1, nonadecene-1, and
mixtures thereof (e.g., mixtures of propylene and butene-1, and the
like). Exemplary of such polymers are propylene homopolymers,
butene-1 homopolymers, ethylene-propylene copolymers,
ethylene-butene-1 copolymers, propylene-butene copolymers and the
like, wherein the polymer contains at least some terminal and/or
internal unsaturation. Preferred polymers are unsaturated
copolymers of ethylene and propylene and ethylene and butene-1. The
interpolymers may contain a minor amount, e.g. 0.5 to 5 mole % of a
C.sub.4 to C.sub.18 non-conjugated diolefin comonomer. However, it
is preferred that the polymers comprise only alpha-olefin
homopolymers, interpolymers of alpha-olefin comonomers and
interpolymers of ethylene and alpha-olefin comonomers. The molar
ethylene content of the polymers employed is preferably in the
range of 0 to 80%, and more preferably 0 to 60%. When propylene
and/or butene-1 are employed as comonomer(s) with ethylene, the
ethylene content of such copolymers is most preferably between 15
and 50%, although higher or lower ethylene contents may be
present.
[0059] These polymers may be prepared by polymerizing alpha-olefin
monomer, or mixtures of alpha-olefin monomers, or mixtures
comprising ethylene and at least one C.sub.3 to C.sub.28
alpha-olefin monomer, in the presence of a catalyst system
comprising at least one metallocene (e.g., a
cyclopentadienyl-transition metal compound) and an alumoxane
compound. Using this process, a polymer in which 95% or more of the
polymer chains possess terminal ethenylidene-type unsaturation can
be provided. The percentage of polymer chains exhibiting terminal
ethenylidene unsaturation may be determined by FTIR spectroscopic
analysis, titration, or C.sup.13 NMR. Interpolymers of this latter
type may be characterized by the formula
POLY-C(R.sup.1).dbd.CH.sub.2 wherein R.sup.1 is C.sub.1 to C.sub.26
alkyl, preferably C.sub.1 to C.sub.18 alkyl, more preferably
C.sub.1 to C.sub.8 alkyl, and most preferably C.sub.1 to C.sub.2
alkyl, (e.g., methyl or ethyl) and wherein POLY represents the
polymer chain. The chain length of the R.sup.1 alkyl group will
vary depending on the comonomer(s) selected for use in the
polymerization. A minor amount of the polymer chains can contain
terminal ethenyl, i.e., vinyl, unsaturation, i.e.
POLY-CH.dbd.CH.sub.2, and a portion of the polymers can contain
internal monounsaturation, e.g. POLY-CH.dbd.CH(R.sup.1), wherein
R.sup.1 is as defined above. These terminally unsaturated
interpolymers may be prepared by known metallocene chemistry and
may also be prepared as described in U.S. Pat. Nos. 5,498,809;
5,663,130; 5,705,577; 5,814,715; 6,022,929 and 6,030,930.
[0060] Another useful class of polymers is polymers prepared by
cationic polymerization of isobutene, styrene, and the like. Common
polymers from this class include polyisobutenes obtained by
polymerization of a C.sub.4 refinery stream having a butene content
of about 35 to about 75 mass %, and an isobutene content of about
30 to about 60 mass %, in the presence of a Lewis acid catalyst,
such as aluminum trichloride or boron trifluoride. A preferred
source of monomer for making poly-n-butenes is petroleum
feedstreams such as Raffinate II. These feedstocks are disclosed in
the art such as in U.S. Pat. No. 4,952,739. Polyisobutylene is a
most preferred backbone of the present invention because it is
readily available by cationic polymerization from butene streams
(e.g., using AlCl.sub.3 or BF.sub.3 catalysts). Such
polyisobutylenes generally contain residual unsaturation in amounts
of about one ethylenic double bond per polymer chain, positioned
along the chain. A preferred embodiment utilizes polyisobutylene
prepared from a pure isobutylene stream or a Raffinate I stream to
prepare reactive isobutylene polymers with terminal vinylidene
olefins. Preferably, these polymers, referred to as highly reactive
polyisobutylene (HR-PIB), have a terminal vinylidene content of at
least 65%, e.g., 70%, more preferably at least 80%, most
preferably, at least 85%. The preparation of such polymers is
described, for example, in U.S. Pat. No. 4,152,499. HR-PIB is known
and HR-PIB is commercially available under the tradenames
Glissopal.TM. (from BASF) and Ultravis.TM. (from BP-Amoco).
[0061] Polyisobutylene polymers that may be employed are generally
based on a hydrocarbon chain of from 400 to 3000. Methods for
making polyisobutylene are known. Polyisobutylene can be
functionalized by halogenation (e.g. chlorination), the thermal
"ene" reaction, or by free radical grafting using a catalyst (e.g.
peroxide), as described below.
[0062] To produce (C) the hydrocarbon or polymer backbone may be
functionalized, with carboxylic anhydride-producing moieties
selectively at sites of carbon-to-carbon unsaturation on the
polymer or hydrocarbon chains, or randomly along chains using any
of the three processes mentioned above or combinations thereof, in
any sequence.
[0063] Processes for reacting polymeric hydrocarbons with
unsaturated carboxylic, anhydrides and the preparation of
derivatives from such compounds are disclosed in U.S. Pat. Nos.
3,087,936; 3,172,892; 3,215,707; 3,231,587; 3,272,746; 3,275,554;
3,381,022; 3,442,808; 3,565,804; 3,912,764; 4,110,349; 4,234,435;
5,777,025; 5,891,953; as well as EP 0 382 450 B1; CA-1,335,895 and
GB-A-1,440,219. The polymer or hydrocarbon may be functionalized,
with carboxylic acid anhydride moieties by reacting the polymer or
hydrocarbon under conditions that result in the addition of
functional moieties or agents, i.e., acid, anhydride, onto the
polymer or hydrocarbon chains primarily at sites of
carbon-to-carbon unsaturation (also referred to as ethylenic or
olefinic unsaturation) using the halogen assisted functionalization
(e.g. chlorination) process or the thermal "ene" reaction.
[0064] Selective functionalization can be accomplished by
halogenating, e.g., chlorinating or brominating the unsaturated
a-olefin polymer to about 1 to 8 mass %, preferably 3 to 7 mass %
chlorine, or bromine, based on the weight of polymer or
hydrocarbon, by passing the chlorine or bromine through the polymer
at a temperature of 60 to 250.degree. C., preferably 110 to
160.degree. C., e.g., 120 to 140.degree. C., for about 0.5 to 10,
preferably 1 to 7 hours. The halogenated polymer or hydrocarbon
(hereinafter backbone) is then reacted with sufficient
monounsaturated reactant capable of adding the required number of
functional moieties to the backbone, e.g., monounsaturated
carboxylic reactant, at 100 to 250.degree. C., usually about
180.degree. C. to 235.degree. C., for about 0.5 to 10, e.g., 3 to 8
hours, such that the product obtained will contain the desired
number of moles of the monounsaturated carboxylic reactant per mole
of the halogenated backbones. Alternatively, the backbone and the
monounsaturated carboxylic reactant are mixed and heated while
adding chlorine to the hot material.
[0065] While chlorination normally helps increase the reactivity of
starting olefin polymers with monounsaturated functionalizing
reactant, it is not necessary with some of the polymers or
hydrocarbons contemplated for use in the present invention,
particularly those preferred polymers or hydrocarbons which possess
a high terminal bond content and reactivity. Preferably, therefore,
the backbone and the monounsaturated functionality reactant,
(carboxylic reactant), are contacted at elevated temperature to
cause an initial thermal "ene" reaction to take place. Ene
reactions are known.
[0066] The hydrocarbon or polymer backbone can be functionalized by
random attachment of functional moieties along the polymer chains
by a variety of methods. For example, the polymer, in solution or
in solid form, may be grafted with the monounsaturated carboxylic
reactant, as described above, in the presence of a free-radical
initiator. When performed in solution, the grafting takes place at
an elevated temperature in the range of about 100 to 260.degree.
C., preferably 120 to 240.degree. C. Preferably, free-radical
initiated grafting would be accomplished in a mineral lubricating
oil solution containing, e.g., 1 to 50 mass %, preferably 5 to 30
mass % polymer based on the initial total oil solution.
[0067] The free-radical initiators that may be used are peroxides,
hydroperoxides, and azo compounds, preferably those that have a
boiling point greater than about 100.degree. C. and decompose
thermally within the grafting temperature range to provide
free-radicals. Representative of these free-radical initiators are
azobutyronitrile, 2,5-dimethylhex-3-ene-2, 5-bis-tertiary-butyl
peroxide and dicumene peroxide. The initiator, when used, typically
is used in an amount of between 0.005% and 1% by weight based on
the weight of the reaction mixture solution. Typically, the
aforesaid monounsaturated carboxylic reactant material and
free-radical initiator are used in a weight ratio range of from
about 1.0:1 to 30:1, preferably 3:1 to 6:1. The grafting is
preferably carried out in an inert atmosphere, such as under
nitrogen blanketing. The resulting grafted polymer is characterized
by having carboxylic acid (or derivative) moieties randomly
attached along the polymer chains: it being understood, of course,
that some of the polymer chains remain ungrafted. The free radical
grafting described above can be used for the other polymers and
hydrocarbons of the present invention.
[0068] The preferred monounsaturated reactants that are used to
functionalize the backbone comprise mono- and dicarboxylic acid
material, i.e., acid, or acid derivative material, including (i)
monounsaturated C.sub.4 to C.sub.10 dicarboxylic acid wherein (a)
the carboxyl groups are vicinyl, (i.e., located on adjacent carbon
atoms) and (b) at least one, preferably both, of said adjacent
carbon atoms are part of said mono unsaturation; (ii) derivatives
of (i) such as anhydrides or C.sub.1 to C.sub.5 alcohol derived
mono- or diesters of (i); (iii) monounsaturated C.sub.3 to C.sub.10
monocarboxylic acid wherein the carbon-carbon double bond is
conjugated with the carboxy group, i.e., of the structure
--C.dbd.C--CO--; and (iv) derivatives of (iii) such as C.sub.1 to
C.sub.5 alcohol derived mono- or diesters of (iii). Mixtures of
monounsaturated carboxylic materials (i)-(iv) also may be used.
Upon reaction with the backbone, the monounsaturation of the
monounsaturated carboxylic reactant becomes saturated. Thus, for
example, maleic anhydride becomes backbone-substituted succinic
anhydride, and acrylic acid becomes backbone-substituted propionic
acid. Exemplary of such monounsaturated carboxylic reactants are
fumaric acid, itaconic acid, maleic acid, maleic anhydride,
chloromaleic acid, chloromaleic anhydride, acrylic acid,
methacrylic acid, crotonic acid, cinnamic acid, and lower alkyl
(e.g., C.sub.1 to C.sub.4 alkyl) acid esters of the foregoing,
e.g., methyl maleate, ethyl fumarate, and methyl fumarate.
[0069] To provide the required functionality, the monounsaturated
carboxylic reactant, preferably maleic anhydride, typically will be
used in an amount ranging from about equimolar amount to about 100
mass % excess, preferably 5 to 50 mass % excess, based on the moles
of polymer or hydrocarbon. Unreacted excess monounsaturated
carboxylic reactant can be removed from the final dispersant
product by, for example, stripping, usually under vacuum, if
required.
[0070] The alkylated phenol may be derived from cashew nut shell
liquid (CNSL), such as hydrogenated cardanol which predominantly
contains 3-pentadecylphenol.
[0071] A characteristic structural feature of the alkyl phenol
derived from CNSL is meta hydrocarbyl-substitution of the aromatic
ring where the substituent is attached to the ring at its first
(C1) carbon atom. This structural feature is not available by
chemical alkyl phenol synthesis such as the Friedel-Crafts reaction
of phenol with olefins. The latter typically gives mixtures of
ortho and para alkyl phenols (but only around 1% of meta alkyl
phenols), and where attachment of the alkyl group to the aromatic
ring is at the second (C2) or higher carbon atom.
[0072] Cardanol, the product obtained by distilling technical CNSL,
typically contains 3-pentadecylphenol (3%);
3-(8-pentadecenyl)phenol (34-36%); 3-(8,11-pentadecadienyl)phenol
(21-22%); and 3-(8,11,14-pentadecatrienyl)phenol (40-41%), plus a
small amount of 5-(pentadecyl)resorcinol (c. 10%), also referred to
as cardol. Technical CNSL contains mainly cardanol plus some
polymerized material. Cardanol may therefore be expressed as
containing significant amounts of meta-linear hydrocarbyl
substituted phenol, where the hydrocarbyl group has the formula
C15H25-31 and is attached to the aromatic ring at its first carbon
atom (C1).
[0073] Thus, both cardanol and technical CNSL contain significant
quantities of material having long linear unsaturated side chains
and only small quantities of material with long linear saturated
side chains. The present invention may employ material where a
major proportion, preferably all of the phenol, contains material
with long linear saturated side chains. Such latter material is
obtainable by hydrogenating cardanol; a preferred example is
3-(pentadecyl)phenol, where the pentadecyl group is linear and is
attached to the aromatic ring at its first carbon atom. It may
constitute 50 or more, 60 or more, 70 or more, 80 or more, or 90 or
more, mass % of the additive of the invention. It may contain small
quantities of 3-(pentadecyl)resorcinol.
[0074] The alkylated phenol may be the product of the
Friedel-Crafts alkylation of phenol with a
C.sub.14/C.sub.16/C.sub.18 mixture of linear alpha olefins (small
levels of other olefins also present, e.g. C.sub.12 and C.sub.20).
This produces a product that is highly C2 attached (alkyl chain
attached at 2nd carbon to the aromatic ring), with some C3 and
higher attachment also seen. A mixture of ortho- and para-alkylated
species (approximately 70% to 30%) are observed, along with around
10% dialkylated material.
[0075] The treat rate of additive (C) in the lubricating oil
composition may for example, be 0.1 to 10, preferably 0.5 to 9,
more preferably 1 to 8, mass %.
Co-Additives
[0076] The lubricating oil composition of the invention may
comprise further additives, different from and additional to (B)
and (C). Such additional additives may, for example include ashless
dispersants, other metal detergents, anti-wear agents such as zinc
dihydrocarbyl dithiophosphates, anti-oxidants and demulsifiers. In
some cases, an ashless dispersant need not be provided.
[0077] It may be desirable, although not essential, to prepare one
or more additive packages or concentrates comprising the additives,
whereby additives (B) and (C) can be added simultaneously to the
base oil to form the lubricating oil composition. Dissolution of
the additive package(s) into the lubricating oil may be facilitated
by solvents and by mixing accompanied with mild heating, but this
is not essential. The additive package(s) will typically be
formulated to contain the additive(s) in proper amounts to provide
the desired concentration, and/or to carry out the intended
function in the final formulation when the additive package(s)
is/are combined with a predetermined amount of base lubricant.
Thus, additives (B) and (C), in accordance with the present
invention, may be admixed with small amounts of base oil or other
compatible solvents together with other desirable additives to form
additive packages containing active ingredients in an amount, based
on the additive package, of, for example, from 2.5 to 90,
preferably from 5 to 75, most preferably from 8 to 60, mass % of
additives in the appropriate proportions, the remainder being base
oil.
EXAMPLES
[0078] The present invention is illustrated by but in no way
limited to the following examples.
Components
[0079] The following components were used: [0080] Component (A):
[0081] (A1): an API Group II 600R basestock from Chevron [0082]
(A2): an API Group I basestock [0083] Component (B): [0084] (B1): a
calcium salicylate detergent having a basicity index of 5.5. [0085]
Component (C): [0086] (C1) A polyisobutene succinic anhydride
("PIBSA") derived from a polyisobutene of number average molecular
weight 950 (72% ai). [0087] (C2) Hydrogenated cardenol ("CNSI,"
phenol) [0088] (C3) Friedel-Crafts alkylated phenol ("SHOP" phenol)
[0089] HFO: a heavy fuel oil, ISO-F-RMK380
System Lubricants
[0090] Selections of the above components were blended to give a
range of system lubricating oil compositions. Some of the
lubricants are examples of the invention and others are reference
examples for comparison purposes. The compositions of the
lubricants tested are shown in the tables below under the "RESULTS"
heading.
Testing
Light Scattering
[0091] Test lubricants were evaluated for asphaltene dispersancy
using light scattering according to the Focused Beam Reflectance
Method ("FBRM"), which predicts asphaltene agglomeration.
[0092] The FBRM test method was disclosed at the 7.sup.th
International Symposium on Marine Engineering, Tokyo, 24-28 Oct.
2005, and was published in `The Benefits of Salicylate Detergents
in TPEO Applications with a Variety of Base Stocks`, in the
Conference Proceedings. Further details were disclosed at the CIMAC
Congress, Vienna, 21-24 May 2007 and published in "Meeting the
Challenge of New Base Fluids for the Lubrication of Medium Speed
Marine Engines--An Additive Approach" in the Congress Proceedings.
In the latter paper it is disclosed that by using the FBRM method
it is possible to obtain quantitative results for asphaltene
dispersancy that predict performance for lubricant systems based on
base stocks containing greater than or less than 90% saturates, and
greater than or less than 0.03% sulphur. The predictions of
relative performance obtained from FBRM were confirmed by engine
tests in marine diesel engines.
[0093] The FBRM probe contains fibre optic cables through which
laser light travels to reach the probe tip. At the tip, an optic
focuses the laser light to a small spot. The optic is rotated so
that the focussed beam scans a circular path between the window of
the probe and the sample. As particles flow past the window they
intersect the scanning path, giving backscattered light from the
individual particles.
[0094] The scanning laser beam travels much faster than the
particles; this means that the particles are effectively
stationary. As the focussed beam reaches one edge of the particle
there is an increase in the amount of backscattered light; the
amount will decrease when the focussed beam reaches the other edge
of the particle.
[0095] The instrument measures the time of the increased
backscatter. The time period of backscatter from one particle is
multiplied by the scan speed and the result is a distance or chord
length. A chord length is a straight line between any two points on
the edge of a particle. This is represented as a chord length
distribution, a graph of numbers of chord lengths (particles)
measured as a function of the chord length dimensions in microns.
As the measurements are performed in real time the statistics of a
distribution can be calculated and tracked. FBRM typically measures
tens of thousands of chords per second, resulting in a robust
number-by-chord length distribution. The method gives an absolute
measure of the particle size distribution of the asphaltene
particles.
[0096] The Focused beam Reflectance Probe (FBRM), model Lasentec
D600L, was supplied by Mettler Toledo, Leicester, UK. The
instrument was used in a configuration to give a particle size
resolution of 1 .mu.m to 1 mm. Data from FBRM can be presented in
several ways. Studies have suggested that the average counts per
second can be used as a quantitative determination of asphaltene
dispersancy. This value is a function of both the average size and
level of agglomerate. In this application, the average count rate
(over the entire size range) was monitored using a measurement time
of one minute per reading over 30 minutes.
[0097] The test lubricant formulations were heated to 60.degree. C.
and stirred at 400 rpm; when the temperature reached 60.degree. C.
the FBRM probe was inserted into the sample and measurements made
for 30 minutes. An aliquot of heavy fuel oil (10% w/w) was
introduced into the lubricant formulation under stirring using a
four blade stirrer (at 400 rpm). A value for the average counts per
second was taken when the count rate had reached an equilibrium
value.
Results
[0098] The results of the FBRM tests are summarised in the tables
below, where lower particle count values indicate better
performance.
TABLE-US-00002 TABLE 1 Three system lubricants contained a
zinc-containing dispersant booster with 0.5% nitrogen and 0.95%
zinc, and 10% HFO. The lubricants also contained the salicylate
detergent (B1) at a treat rate of 3.8%. One lubricant comprised a
Group I basestock and no PIBSA; the second lubricant comprised a
Group II basestock and no PIBSA; the third lubricant comprised a
Group II basestock and PIBSA (C) at a treat rate of 7%. GROUP I
(A1) GROUP II (A2) GROUP II + PIBSA 26,431 39,032 14,812
[0099] The numbers are particulate counts.
[0100] The results show that, in Group II oil, salicylate gives an
inferior performance than its use in Group I oil. However, the
right-hand column shows that addition of PIBSA significantly
improves the performance of salicylate to the extent that it is
better than the Group I salicylate-containing lubricant.
TABLE-US-00003 TABLE 2 A set of system lubricants, of 5 BN,
comprised a Group II basestock (A1) and a salicylate package (B1)
at a treat rate of 2%. PIBSA, CNSL phenol and SHOP phenol were
either absent or present in different amounts as indicated. Mass
PIBSA "CNSL" "SHOP" % Particle Count(s) Particle Counts Particle
Counts -- 7,160 7,160 7,160 2 1,621 5,944 6,241 4 831 1,329 4,757 6
454 28 1,770 8 366 77 317
[0101] The results show that improvement occurs at the lowest treat
rate of 2% and that further improvement is possible at higher treat
rates. It should be noted that, at higher treat rates, viscosity
may be increased.
* * * * *