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Claims  |
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What is claimed is:
1. A copolymer consisting essentially of:
(A) 10-94% by mole of acrylic ester units having the formula
##STR6##
wherein R.sup.1 is H or CH.sub.3 ; and R.sup.2 is C.sub.1-30 alkyl; (B)
3-65% by mole of dicarboxylic units having the formula
##STR7##
wherein R.sup.3 and R.sup.4 are each independently H or CH.sub.3 ; X and
Y are each independently OR.sup.2, OR.sup.5 or NHR.sup.5 ; wherein R.sup.2
is C.sub.1-30 alkyl; and R.sup.5 is H or a monovalent organic radical; and
(C) 3-40% by mole of diisobutylene units having the formula
##STR8##
wherein the molar proportion of the units having the formula (B) is at
least as high as the molar proportion of the units having the formula (C);
and wherein said copolymer has a number average molecular weight of
500-250,000.
2. A copolymer according to claim 1, wherein in at least a portion of the
units having the formula (A), R.sup.1 is CH.sub.3 and R.sup.2 is
C.sub.4-18 alkyl.
3. A copolymer according to claim 1, wherein in at least a portion of the
units having the formula (A), R.sup.1 is H and R.sup.2 is C.sub.4-22
alkyl.
4. A copolymer according to claim 1, wherein in at least a portion of the
units having the formula (B), R.sup.3 and R.sup.4 are each H.
5. A copolymer according to claim 1, wherein at least a portion of the
dicarboxylic units (B) have the formula
##STR9##
wherein R.sup.3 and R.sup.4 are each independently H or CH.sub.3.
6. A copolymer according to claim 1, wherein at least a portion of the
dicarboxylic units (B) have the formula
##STR10##
wherein R.sup.3 and R.sup.4 are each independently H or CH.sub.3 ; and
wherein at least one of X and Y is OR.sup.2 or OR.sup.5, R.sup.2 being
butyl or C.sub.18 alkyl, and R.sup.5 being the monovalent organic radical
corresponding to the alcohol R.sup.5 OH, wherein R.sup.5 OH is
pentaerythritol, glycerol, trimethylolpropane, diethylethanolamine or
diethanolamine.
7. A copolymer according to claim 1, wherein at least a portion of the
dicarboxylic units (B) have the formula
##STR11##
wherein R.sup.3 and R.sup.4 are each independently H or CH.sub.3 ; and
wherein at least one of X and Y is NHR.sup.5, R.sup.5 in all occurrences
being the monovalent organic radical corresponding to the amine R.sup.5
NH.sub.2, wherein R.sup.5 NH.sub.2 is dimethylaminopropylamine,
triethylenetetramine, tetraethylenepentamine, 2-aminopyridine or
1-cyanoguanidine.
8. A hydrocarbon oil composition comprising a major proportion of
hydrocarbon oil and a minor proportion of at least one copolymer according
to claim 1 sufficient to improve the cold-flow properties of said
hydrocarbon oil.
9. A composition according to claim 8, wherein said hydrocarbon oil is a
lubricating oil and said copolymer has 20 to 90% by mole of units having
the formula (A), 5 to 65% by mole of units having the formula (B) and 5 to
40% by mole of units having the formula (C).
10. A composition according to claim 9, wherein in said copolymer, the
units having the formula (A) amount to 40-75% by mole, the units having
the formula (B) amount to 10-40% by mole and the units having the formula
(C) amount to 10-30% by mole.
11. A composition according to claim 9, wherein the number average
molecular weight of said copolymer is from 3,000 to 70,000.
12. A composition according to claim 9, wherein the proportion of said
copolymer is from 0.01 to 4% by weight.
13. A composition according to claim 12, wherein the proportion of said
copolymer is from 0.5 to 2% by weight.
14. A composition according to claim 9, wherein in said copolymer, in at
least a portion of the units having the formula (A), R.sup.1 is CH.sub.3
and R.sup.2 is C.sub.4-18 alkyl.
15. A composition according to claim 9, wherein in said copolymer, in at
least a portion of the units having the formula (B), R.sup.3 and R.sup.4
are each H.
16. A composition according to claim 9, wherein in said copolymer, at least
a portion of the dicarboxylic units (B) have the formula
##STR12##
wherein R.sup.3 and R.sup.4 are each independently H or CH.sub.3.
17. A composition according to claim 9, wherein in said copolymer, at least
a portion of the dicarboxylic units (B) have the formula
##STR13##
wherein R.sup.3 and R.sup.4 are each independently H or CH.sub.3 ; and
wherein at least one of X and Y is OR.sup.2 or OR.sup.5, R.sup.2 being
butyl or C.sub.18 alkyl, and R.sup.5 being the monovalent organic radical
corresponding to the alcohol R.sup.5 OH, wherein R.sup.5 OH is
pentaerythritol, glycerol, trimethylolpropane, diethylethanolamine or
diethanolamine.
18. A composition according to claim 9, wherein in said copolymer, at least
a portion of the dicarboxylic units (B) have the formula
##STR14##
wherein R.sup.3 and R.sup.4 are each independently H or CH.sub.3 ; and
wherein at least one of X and Y is NHR.sup.5, R.sup.5 in all occurrences
being the monovalent organic radical corresponding to the amine R.sup.5
NH.sub.2, wherein R.sup.5 NH.sub.2 is dimethylaminopropylamine,
triethylenetetramine, tetraethylenepentamine, 2-aminopyridine or
1-cyanoguanidine.
19. A composition according to claim 8, wherein the hydrocarbon oil is
diesel oil, domestic fuel oil, heavy fuel oil, fuel oil No. 2, residual
fuel oil or crude petroleum, and wherein said copolymer has from 10 to 94%
by mole of units having the formula (A), from 3 to 50% by mole of units
having the formula (B) and from 3 to 40% by mole of units having the
formula (C), and has a number average molecular weight of from 500 to
200,000.
20. A composition according to claim 19, wherein said terpolymer has from
40 to 80% by mole of units having the formula (A), from 10 to 35% by mole
of units having the formula (B) and from 10 to 25% by mole of units having
the formula (C).
21. A composition according to claim 19, wherein the number average
molecular weight of said terpolymer is from about 1,000 to 70,000.
22. A composition according to claim 19, wherein the proportion of said
copolymer is from 0.005 to 2% by weight.
23. A composition according to claim 22, wherein the proportion of said
copolymer is from 0.01 to 0.5% by weight.
24. A composition according to claim 19, wherein in said copolymer, in at
least a portion of the units having the formula (A), R.sup.1 is H and
R.sup.2 is C.sub.4-22 alkyl.
25. A composition according to claim 24, wherein R.sub.2 is butyl,
2-ethylhexyl, lauryl, stearyl, eicosyl or docosyl.
26. A composition according to claim 19, wherein in said copolymer, in at
least a portion of the units having the formula (B), R.sup.3 and R.sup.4
are each H.
27. A composition according to claim 19, wherein in said copolymer, at
least a portion of the dicarboxylic units (B) have the formula
##STR15##
wherein R.sup.3 and R.sup.4 are each independently H or CH.sub.3.
28. A composition according to claim 19, wherein in said copolymer, at
least a portion of the dicarboxylic units (B) have the formula
##STR16##
wherein R.sup.3 and R.sup.4 are each independently H or CH.sub.3 ; and
wherein at least one of X and Y is OR.sup.2 or OR.sup.5, R.sup.2 being
butyl or C.sub.18 alkyl, and R.sup.5 being the monovalent organic radical
corresponding to the alcohol R.sup.5 OH, wherein R.sup.5 OH is
pentaerythritol, glycerol, trimethylolpropane, diethylethanolamine or
diethanolamine.
29. A composition according to claim 19, wherein in said copolymer, at
least a portion of the dicarboxylic units (B) have the formula
##STR17##
wherein R.sup.3 and R.sup.4 are each independently H or CH.sub.3 ; and
wherein at least one of X and Y is NHR.sup.5, R.sup.5 in all occurrences
being the monovalent organic radical corresponding to the amine R.sup.5
NH.sub.2, wherein R.sup.5 NH.sub.2 is dimethylaminopropylamine,
triethylenetetramine, tetraethylenepentamine, 2-aminopyridine or
1-cyanoguanidine.
30. A method of improving the cold-flow properties of a hydrocarbon oil,
comprising adding to said oil an amount sufficient to improve its
cold-flow properties of a copolymer according to claim 1. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
This invention relates to new terpolymers which can be used, for example,
as additives improving the cold-flow properties of lubricating oils and
various hydrocarbon oils.
It also relates to lubricating oil compositions comprising these
terpolymers.
It also relates to hydrocarbon oils such as diesel oils, domestic fuel
oils, heavy fuel oils (fuel oils No. 2), residual fuel oils or crude oils
whose congealing point or freezing point is decreased by adding
terpolymers soluble in these hydrocarbon oils.
The lubricating oil compositions adapted to internal combustion engines and
to automatic power transmissions require, in the base oil, associated
additives exhibiting a number of properties, in addition to their
lubricating power. These properties comprise decreasing the freezing point
or the congealing point of the oil, heat stability and resistance to
oxidation, rust and corrosion inhibition, dispersion of the carbon
deposits and of the insoluble materials formed by fuel combustion and oil
oxidation, neutralization of the acid materials formed by oil oxidation
and finally improvement of the viscosity index.
Various compositions have been described in the literature, which comprise
copolymers obtained by the addition reaction of alpha-olefins with
dicarboxylic alkenes, which are thereafter esterified with long chain
saturated straight-chain alcohols, so as to make the copolymers soluble in
hydrocarbon oils in appropriate manner; polyamino compounds are then
added, so as to form dispersion agents or agents improving the viscosity
index of lubricants.
Polymeric acrylic esters are also known to decrease the freezing point or
the congealing point of lubricating oils, and a known factor having a
particularly great influence in that case is the length of the lateral
alkyl chains; the presence of a sufficient number of long lateral alkyl
chains is apparently decisive to obtain sufficient solubility of the
additive in hydrocarbon oils.
Finally, it is also known that, although copolymers of acrylic esters with
certain alpha-olefins, such as ethylene or propylene, can be obtained
easily, it is impossible to obtain copolymers of acrylic esters having a
high diisobutylene content, taking the too low reactivity of this monomer
into account.
It has now been found that copolymers of acrylic esters containing an
important proportion of diisobutylene can be obtained easily (particularly
in moderate conditions of temperature and pressure) by adding an
ethylenically unsaturated dicarboxylic compound, in at least equimolar
proportion with respect to diisobutylene, to the monomer mixture.
It has also been found that the resultant terpolymers greatly improve the
cold-flow properties of lubricating oils, the presence of diisobutylene
units in these additives improving their solubility in hydrocarbon oils.
Another advantage of the terpolymer additives of the invention, as compared
with the anti-freeze additives of the prior art, containing acrylic
esters, lies in the possibility to also improve the dispersion effect, the
presence of carboxylic anhydride or carboxylic acid units in the
terpolymers of the invention allowing a further reaction with (poly-)amino
and/or (poly-)hydroxy compounds.
Finally the use of these terpolymers as additives having both improved
properties for decreasing the freezing point or the congealing point and
dispersion properties for lubricants is advantageous from the economic
point of view, since, on the one hand, incorporating important amounts of
diisobutylene and maleic anhydride into acrylic esters contributes to
decreasing the final price of the additive, without disadvantage as
concerns the properties, and, on the other hand, the dispersant properties
of the anti-freeze additive provide for a reduction or suppression of an
additional use of conventional dispersant additives for lubricating oils.
It is well known that certain hydrocarbon oils contain such compounds as
paraffins, asphaltenes or resins which make them viscous and impart
unacceptable flow properties. These oils behave at low temperature as
non-newtonian fluids; they have a congealing or freezing point, as well as
particular hysteresis properties which greatly limit their use, for
example, as fuel oils, and their production, particularly, as far as crude
oil are concerned.
A prior technique which obviates these disadvantages consists of subjecting
the hydrocarbon oils to dewaxing or deasphalting processes; however these
processes are often very expensive.
Another technique which is used to decrease the viscosity or the freezing
point of the hydrocarbon oils having a high content of asphaltic and/or
paraffinic compounds consists of diluting them by adding lighter
hydrocarbon oils or distillates. This is also an expensive technique since
light oils have a far higher cost than heavy oils.
A third technique, which is very often the least expensive and has the
highest efficiency, consists of adding small amounts of polymeric
additives to fluidify the hydrocarbon oil or improve its cold-flow
properties.
Among the numerous additives proposed in the prior art, mention may be made
of polymers or copolymers based on .alpha.-olefins or diolefins,
optionally hydrogenated and/or alkylated, the polymers or copolymers of
unsaturated esters, such as acrylates or methacrylates, as well as certain
copolymers of .alpha.-olefins with unsaturated esters, such as copolymers
of ethylene or propylene with vinyl acetate or with acrylates and
methacrylates. These additives are known to decrease the limit
filterability temperature of diesel oils or domestic fuel oils, and to
improve the cold-flow properties of certain highly paraffinic fuel oils or
crude oils. However these additives are not very efficient to improve the
fluidity and the flow properties of heavy hydrocarbon oils, such as
high-boiling fuel oils, fuel oils No. 2, residues of atmospheric
distillation (residual fuel oils) or highly asphaltenic crude oils.
It has now been found that the cold-flow properties of these hydrocarbon
oil compositions (particularly fluidity, in the case of heavy oils) can be
improved by adding small amounts of certain terpolymers, as hereinafter
defined.
OBJECTS OF THE INVENTION
The present invention has for object to supply additives improving the
cold-flow properties of lubricating oils, particularly by decreasing their
freezing point or congealing point. It has also for object to supply a
multi-functional additive for lubricating oils which has a desirable range
of properties, in addition to the individual property of decreasing the
pour point, such as improving the detergent and dispersant properties and
the viscosity index.
It has also for object to supply additives improving the cold-flow
properties of hydrocarbon oils such as diesel oils, domestic fuel oils,
heavy fuel oils, fuel oil No. 2, residual fuel oils and crude oils.
DETAILED DISCUSSION
The terpolymers of the invention may be defined generally as comprising
units of at least one acrylic ester, at least one ethylenically
unsaturated .alpha.,.beta.-dicarboxylic compound and diisobutylene, these
terpolymers being optionally reacted thereafter with at least one
(poly-)amino and/or (poly-)hydroxy compound.
The terpolymers of the invention are mainly characterized in that they
comprise at least three different types of units:
(A) acrylic ester units of the general formula
##STR1##
in which R.sup.1 is a hydrogen atom or a methyl radical and R.sup.2 is an
alkyl radical of 1-30 carbon atoms or a mixture of these radicals;
(B) .alpha.,.beta.-dicarboxylic units complying with one of the general
formulas:
##STR2##
in which R.sup.3 and R.sup.4, which are identical or different, represent
a hydrogen atom or a methyl radical, X and Y, which are identical or
different, are selected from the --OH, --OR.sup.2, --OR.sup.5, --NH.sub.2
and --NHR.sup.5 groups, where R.sup.2 is above defined and R.sup.5 is a
monovalent organic radical derived from a compound having at least one
hydroxy group and/or at least one amino group;
and (C) units of the formula
##STR3##
as obtained from diisobutylene.
The respective proportions of the (A), (B) and (C) units in the terpolymers
of the invention are usually from 10 to 94% by mole for the (A) units,
from 3 to 65% by mole for the (B) units and from 3 to 40% by mole for the
(C) units. It is also advantageous that the content of (B) units, as
obtained from an ethylenically unsaturated dicarboxylic compound, be at
least the same as the content of the (C) units, as obtained from
diisobutylene. Their average molecular weight by number is usually from
500 to 250,000.
The terpolymers of the invention may be manufactured according to
conventional polymerization methods, via the radical method, for example
in the presence of an initiator of the azobisisobutyronitrile or peroxide
type, in bulk or in solution in a hydrocarbon solvent, for example,
cyclohexane, isooctane, dodecane, benzene, toluene, xylene,
diisopropylbenzene, tetrahydrofuran or dioxan. High boiling hydrocarbon
cuts are preferred, such as kerosine or diesel oil.
If desired, the polymerization may be effected in a lubricating oil.
It is usually operated under atmospheric pressure and at a temperature not
in excess of 140.degree. C., e.g. between 60.degree. and 120.degree. C.
Appropriate proportions of the monomers are used, usually at least one
molar proportion of ethylenically unsaturated .alpha.,.beta.-dicarboxylic
compound (for example, maleic anhydride) per molar proportion of
diisobutylene.
If it is desired to obtain terpolymers according to the invention having
ester, amide or imide groups in at least one portion of the (B) units, it
is possible to thereafter react the reaction mixture with a (poly-)amino
and/or (poly-)hydroxy compound at a temperature usually between 80.degree.
and 160.degree. C. (optionally in the presence of a small amount of an
acid soluble in a hydrocarbon phase, when the compound is essentially of
the (poly-)hydroxy type.
The terpolymers of the invention, which can be used more particularly as
additives improving the cold-flow properties of lubricating oils, have the
following useful properties.
The acrylic esters which supply the (A) units consist more particularly of
compounds of the general formula
##STR4##
wherein R.sup.1 is preferably a methyl radical and R.sup.2 is an alkyl
radical of 1-30 carbon atoms, preferably 4-18 carbon atoms.
Examples of such compounds are mainly methyl, propyl, butyl, 2-ethy hexyl,
decyl, dodecyl, hexadecyl, octadecyl and eicosyl methacrylates. Butyl
methacrylate is used with advantage, as well as methacrylates of
industrial alcohol cuts having 12 carbon atoms (lauryl methacrylate) or 18
carbon atoms (stearyl methacrylate) as an average.
The ethylenically unsaturated .alpha.,.beta.-dicarboxylic compounds
supplying the (B) units consist more particularly of the maleic or
citraconic anhydrides or acids, or fumaric or mesaconic acids or the
corresponding derivatives having at least one ester or amide group, or the
corresponding, optionally N-substituted imides; greater use is made of
maleic compounds.
The respective proportions of the (A), (B) and (C) units in the terpolymers
may vary widely.
Thus, for example, these terpolymers may comprise from 20 to 90%,
preferably from 40 to 75% by mole of units of the formula (A), from 5 to
65%, preferably from 10 to 40% by mole of units of the formula (B) and
from 5 to 40%, preferably from 10 to 30% by mole of units of the formula
(C).
Their average molecular weight by number, determined by tonometry or
osmometry, is usually selected between 500 and 250,000, preferably from
3,000 to 70,000.
When a (poly-)amino and/or a (poly-)hydroxy compound is used to prepare
terpolymers according to the invention, useful as additives for
lubricating oils, in order to obtain heat-stable products having
satisfactory qualities of dispersivity, while retaining sufficient
solubility of the terpolymers in a lubricating oil, this compound is
preferably selected from 3-dimethylaminopropylamine, triethylene
tetramine, tetraethylene pentamine, 2-amino pyridine, diethylethanolamine,
diethanolamine, 1-cyano guanidine, trimethylolpropane, glycerol or
pentaerythritol.
According to a particularly preferred embodiment of the process for
manufacturing the additive of the invention, a concentrated solution is
directly prepared, containing about 10 to 40% by weight of terpolymer in a
solvent consisting of an appropriate oil, for example, a neutral mineral
oil or a lubricating oil having a viscosity between about 75 and about 350
universal Saybolt seconds at 37.8.degree. C.
The soluble terpolymers of the invention may be incorporated in lubricating
oils (for example in lubricating oils for automotive engines or for
transmissions) at various concentrations, usually between about 0.01 and
4% by weight, preferably between 0.5 and 2% b.w. of the total lubricating
oil.
The lubricants in which the terpolymers of the present invention may be
incorporated comprise not only hydrocarbon oils or hydrorefined oils of
petroleum, asphaltic sand, shale or coal origin, but also synthetic oils,
such as alkylene polymers or alkylene oxide polymers, alkylbenzenes,
dialkylbenzenes and polyphenyls. The oils consist preferably of naphthenic
or paraffinic bases, or their mixtures.
The additive is advantageously supplied in a pre-diluted form comprising,
for example, from 10 to 60 parts by weight, preferably about 40 parts by
weight, of the additive, dissolved in 90 to 40 parts by weight, preferably
about 60 parts by weight, of a mineral lubricating oil, with or without
other additives.
It is also clear that, without departing from the scope of the invention,
it is also possible to add other conventionally used additives to the
lubricating oil compositions of the invention, such as, for example,
corrosion inhibitors, anti-emulsifying agents, antioxidants, detergents or
dispersants, or again additives improving the viscosity index. Probably
due to a combination of appropriate ester and olefinic units, the
terpolymers of the invention have better compatibility and better
anti-freezing efficiency in the presence of viscosity additives of the
polyolefinic type, which additives find greater and greater use in the
lubricants.
The terpolymers of the invention which can particularly be used as
additives for improving the cold-flow properties of hydrocarbon oils such
as diesel oil, domestic fuel oil, heavy fuel oil, fuel oil No. 2, residual
fuel oil and crude oil have usefully the following properties.
The acrylic esters which supply the units (A) consist particularly of
compounds of the general formula
##STR5##
wherein R.sup.1 is preferably a hydrogen atom and R.sup.2 represents an
alkyl radical of 1-30 carbon atoms, preferably 4-22 carbon atoms.
By way of illustration of acrylic esters supplying the units (A) of the
terpolymers, mention is made of methyl, propyl, butyl, ethylhexyl, decyl,
hexadecyl, dodecyl, octadecyl, eicosyl or docosyl acrylates. Other
examples are the acrylates of industrial alcohol cuts containing 12 carbon
atoms (lauryl acrylate), 18 carbon atoms (stearyl acrylate) or 20 to 22
carbon atoms as an average.
Examples of .alpha.,.beta.-unsaturated dicarboxylic compounds supplying
units (B) of the terpolymers of the invention are maleic or citraconic, or
fumaric or mesaconic acids the corresponding derivatives having at least
one ester or amide group and the corresponding imides (optionally
N-substituted).
Both for reasons of availability and price of the starting materials and
for reasons of solubility and performance of the terpolymers in the
hydrocarbon oils, the monomers supplying the units (A) are preferably
selected from methyl, butyl, ethylhexyl, stearyl, lauryl, eicosyl or
docosyl acrylates, and those supplying the units (B) from maleic
anhydride, maleic or fumaric acid, alkyl maleates and maleimides,
optionally with N-substitution.
The respective contents of the units (A), (B) and (C) in the terpolymers
used in the invention may vary widely. Thus, for example, for 100 units of
these terpolymers, the number of units (A) may be 10 to 94, preferably 40
to 80, the number of units (B) may be 3 to 50, preferably 10 to 35, and
the number of units (C) may be 3 to 40, preferably 10 to 25. It is also
possible to operate somewhat outside of these values, without departing
from the scope of the invention.
The average molecular weight by number of the terpolymers is from 500 to
200,000, preferably 1,000 to 70,000.
When a (poly-)amino and/or (poly-)hydroxy compound is used for
manufacturing terpolymers of the invention, useful as additives for
hydrocarbon oils such as diesel oil, domestic fuel oil, heavy fuel oil,
fuel oil No. 2, residual fuel oil and crude oil, the amidation and/or
imidation and/or esterification reactions for all or part of the
carboxylic groups of the terpolymer, during the second step, confer to the
hydrocarbon oil compositions additional properties of dispersivity and
anti-flocculating agent or agent impeding asphaltene sedimentation, which
properties are often very useful for improving the fluidity of the heavy
hydrocarbon oils. In addition, the esterification of a portion of the
carboxylic groups of the terpolymer with long chain linear saturated
alcohols, having for example up to 30 carbon atoms, may contribute to
increase the solubility of the additive in oil and its activity as pour
point depressant.
According to another embodiment for synthesizing terpolymers according to
the invention, one or more unsaturated monoesters are terpolymerized via
the radical method with a mixture of alkyl maleates and/or maleimides,
optionally N-substituted, and diisobutylene.
For manufacturing the improved hydrocarbon oil compositions of the
invention, there is commonly used from 0.005 to 2% by weight, preferably
from 0.01 to 0.5% b.w., of one or more terpolymers, with respect to the
weight of the hydrocarbon oil.
The terpolymer in powdered or granulated form may be directly admixed with
the oil to be treated; however it is preferably added as a concentrated
solution, for example a solution containing 20 to 60 parts b.w. of
terpolymer dissolved in 80 to 40 parts b.w. of toluene, xylene, kerosine
or diesel oil. The mixture may be made at room temperature; however it is
often better to mix when hot, for example by adding the terpolymer
solution at a temperature from 30.degree. to 150.degree. C.
It is clear that, without departing from the scope of the invention, the
compositions of hydrocarbon oils may also contain other commonly used
additives, such as corrosion inhibitors, anti-emulsifying agents,
antistatic agents, antioxidants, etc.
The following non-limitative examples illustrate various embodiments of the
invention.
EXAMPLE 1
A solution of 22.5 g (66.5.times.10.sup.-3 mole) of stearyl methacrylate,
10 g (89.2.times.10.sup.-3 mole) of diisobutylene and 7.5 g
(76.5.times.10.sup.-3 mole) of maleic anhydride in 80 cc of toluene is
heated up to 90.degree. C. A solution containing 0.3 g of
azobisisobutyronitrile in 20 cc of toluene is slowly added (addition rate:
10 cc/h) and the mixture is stirred at 90.degree. C. for 4 hours.
A portion of the reaction mixture is caused to precipitate in an excess of
methyl alcohol; the precipitate is isolated by filtration and dried under
reduced pressure up to constant weight. The resultant terpolymer contains
about 54% by mole of stearyl methacrylate, 20% by mole of diisobutylene
and 26% by mole of maleic anhydride; it has an average molecular weight by
number of 10,200.
A pre-diluted form of the terpolymer is obtained by admixing the toluenic
solution with a lubricating oil, for example a 200 N or 350 N oil, and
toluene is evaporated thereafter up to constant weight.
EXAMPLE 2
13 g of the terpolymer of example 1 are dissolved into 50 cc of a 200 N
lubricating oil and 2 g of dimethylamino-propylamine are added; the
mixture is stirred for 4 hours at 150.degree. C.
The infra-red spectrum of the resultant solution shows the disappearance of
the absorption band corresponding to the C.dbd.O bonds of the anhydride
type, located initially at about 1775 cm.sup.-1 conversely, a new
absorption band appears at about 1705-1695 cm.sup.-1, attributable to the
C.dbd.O bonds of the imide type.
EXAMPLE 3
A solution of 14 g (41.4.times.10.sup.-3 mole) of stearyl methacrylate, 6 g
(32.6.times.10.sup.-3 mole) of 2-ethylhexyl acrylate, 7 g
(62.5.times.10.sup.-3 mole) of diisobutylene and 10 g
(10.2.times.10.sup.-2 mole) of maleic anhydride in 100 cc of a 100 N
lubricating oil is heated at 80.degree. C. for 2 hours in the presence of
0.4 g of azobisisobutyronitrile and then at 100.degree. C. for 2 hours.
1.5 g of tetraethylene-pentamine is then added and the mixture is stirred
at 140.degree. C. for 2 hours.
EXAMPLE 4
A mixture of 13 g (51.2.times.10.sup.-3 mole) of lauryl methacrylate, 11 g
(32.5.times.10.sup.-3 mole) of stearyl methacrylate, 6 g
(53.5.times.10.sup.-3 mole) of diisobutylene and 8 g (81.6.times.10.sup.-3
mole) of maleic anhydride is dissolved into 140 cc of toluene. 0.8 g of
dicumyl peroxide is added and the mixture is heated at 120.degree. C. for
2 hours. After addition of 8 g of diethanolamine, heating is continued at
100.degree. C. for 4 hours. A concentrate of additive in a lubricating oil
is prepared by adding 50 cc of a 350 N oil and evaporating toluene under
reduced pressure up to constant weight.
EXAMPLE 5
A mixture of 40 g (12.3.times.10.sup.-2 mole) of stearyl acrylate, 10 g
(70.4.times.10.sup.-3 mole) of butyl methacrylate, 5 g (0.05 mole) of
methyl methacrylate, 25 g (22.3.times.10.sup.-2 mole) of diisobutylene and
30 g (30.6.times.10.sup.-2 mole) of maleic anhydride is heated at
90.degree. C. for 3 hours, in the presence of 1.1 g of benzoyl peroxide,
then at 110.degree. C. for 2 hours. The mixture is then evaporated under
reduced pressure at 110.degree. C. or 1 hour, so as to remove any residual
monomer. The residue is then dissolved under stirring at 100.degree. C.
into 350 cc of a 200 N lubricating oil. 28 g of dimethylaminopropylamine
is added and the solution is stirred at 150.degree. C. for 4 hours.
EXAMPLE 6
A solution of 51 g (15.1.times.10.sup.-2 mole) of stearyl methacrylate, 37
g (14.5.times.10.sup.-2 mole) of lauryl methacrylate and 1.6 g of
azobisisobutyronitrile in 200 cc of dioxane is added in 4 hours to a
solution of 33 g (29.4.times.10.sup.-2 mole) of diisobutylene and 40 g
(40.8.times.10.sup.-2 mole) of maleic anhydride in 200 cc of dioxane at
70.degree. C. Heating at 70.degree. C. is continued for 4 more hours.
Half of the solution is caused to settle in an excess of methyl alcohol and
the precipitate is isolated by filtration, washed with alcohol and dried
under reduced pressure up to constant weight. There is thus obtained 74 g
of terpolymer having an average molecular weight by number of 4700, the
maleic anhydride and diisobutylene contents being respectively 46 and 24%
by mole.
EXAMPLE 7
200 cc of a 100 N lubricating oil are added to the remainder of the
reaction solution of example 6, and dioxane is distilled under reduced
pressure up to constant weight. 40 g of trimethylolpropane and 0.6 g of
paratoluenesulfonic acid are added and the mixture is heated at
150.degree. C. for 4 hours.
The infra-red spectrum of the solution shows the disappearance of the
absorption at frequencies corresponding to the C.dbd.O bonds of the
anhydride groups, the absorption frequence of the newly formed C.dbd.O
bonds of the ester type mingling with that of the ester C.dbd.O bonds of
the methacrylates, located at about 1725-1735 cm.sup.-1.
EXAMPLE 8
The solutions of the various terpolymers described above have been added to
a number of lubricating oils and the decrease of the pour point has been
determined according to the AFNOR NFT 60-105 or ASTM D 97 standard.
As results from the following Table 1, the terpolymers of the invention are
very efficient for decreasing the pour point of lubricants.
TABLE 1
______________________________________
POUR
PRODUCT % b.w. of POINT
OF EXAMPLE TERPOLYMER LUBE OIL .degree.C.
______________________________________
-- 0 200 N -15
-- 0 350 N -9
1 0.5 200 N -30
1 0.5 350 N -27
2 0.5 200 N -30
3 0.5 350 N -24
4 0.5 350 N -30
4 0.3 350 N -27
5 0.5 200 N -35
6 0.5 200 N -26
6 0.5 350 N -24
7 0.5 200 N -26
______________________________________
The dispersant effect of some of the above anti-freezing additives has been
determined according to the spot method described by V. A. Gates and coll.
in the SAE preprint No. 572 (1955) or by A. Schilling in "Oils for engines
and engine lubrication", edit. Technip, tome I, p. 89 (1962). According to
this method, there is determined after 24 h the ratio of the diameters of
two concentrical spots formed by depositing an oil drop containing 2% b.w.
of additive and 1% b.w. of sludge onto a sheet of filter paper. The
results are determined at 20.degree. C. (A), at 200.degree. C. (B) and
after cooling to 20.degree. C. (C).
As shown by the results summarized in the following Table 2, the
terpolymers which decrease the pour point of lubricants according to the
invention may also be efficient dispersion agents, useful also at the low
usual concentrations of the pour point depressant additives.
TABLE 2
______________________________________
PRODUCT DISPERSING EFFECT
OF EXAMPLE (A) (B) (C)
______________________________________
2 0.80 0.75 0.78
2* 0.68 0.69 0.70
3 0.82 0.77 0.79
4 0.75 0.71 0.71
5 0.83 0.81 0.81
5* 0.72 0.71 0.71
7 0.74 0.76 0.78
______________________________________
*In these two cases, 0.5% b.w. of terpolymer was used.
EXAMPLE 9
A mixture of 11 g (110.times.10.sup.-3 mole) of methyl methacrylate, 62 g
(244.times.10.sup.-3 mole) of lauryl methacrylate, 27 g
(79.8.times.10.sup.-3 mole) of stearyl methacrylate, 6 g
(61.2.times.10.sup.-3 mole) of maleic anhydride and 6.7 g
(59.8.times.10.sup.-3 mole) of diisobutylene is dissolved into 82 cc of a
100 N lubricating oil and heated at 100.degree. C. under stirring. 0.386 g
of azobisisobutyronitrile is progressively added, in 4 hours, and
thereafter heating is continued for 1 hour. 6 g (58.8.times.10.sup.-3
mole) of dimethylaminopropylamine is added and the mixture is stirred at
140.degree. C. for 4 hours. A brown-reddish viscous solution is thus
obtained.
6.8 cc of this solution are added to 93.2 cc of a 200 N lubricating oil.
The resultant mixture has a pour point of -29.degree. C., a viscosity of
14.82 centistokes at 100.degree. C. and a piston rating of 84.3
(100=perfectly clean piston) when tested in a diesel engine for 50 hours.
EXAMPLE 10
0.5 g of azobisisobutyronitrile is added to a solution of 32 g
(9.87.times.10.sup.-2 mole) of stearyl acrylate, 11 g
(11.22.times.10.sup.-2 mole) of maleic anhydride and 10 g
(8.92.times.10.sup.-2 mole) of diisobutylene in 250 cc of toluene and the
mixture is stirred at 90.degree. C. for 6 hours.
100 cc of the solution is caused to settle in an excess of methyl alcohol;
the precipitate is isolated by filtration, washed with alcohol and dried
under reduced pressure up to constant weight.
17 g of a terpolymer having an average molecular weight by number of 4100
and containing about 48% by mole of stearyl acrylate, 32% by mole of
maleic anhydride and 20% by mole of diisobutylene is thus obtained.
300 ppm of this terpolymer is added to a Mandji atmospheric residue whose
properties are summarized hereunder:
______________________________________
Specific weight at 15.degree. C. (kg/l)
0.9581
S (% by weight) 1.86
Asphaltenes (% by weight)
2.80
Pour point (.degree.C.) +33
Kinematic viscosity at 50.degree. C.
1060 cst
______________________________________
the pour point is thus decreased to +15.degree. C.
On the other hand, the rheologic behavior of an Egyptian crude oil was
examined with a rotation viscosimeter; it was found that adding 300 ppm of
this terpolymer decreased the yield value and the plastic viscosity.
EXAMPLE 11
3.8 g (3.7.times.10.sup.-2 mole) of dimethylaminopropylamine are added to
100 cc of the solution of example 10 and the mixture is stirred at
150.degree. C. for 4 hours. The terpolymer is then isolated by settling in
methyl alcohol, as in example 10.
The infrared spectrum of the modified polymer, as obtained in these
conditions, shows the disappearance of the absorption band attributable to
the C.dbd.O bonds of the anhydride type, initially located at about 1775
cm.sup.-1 ; conversely, a new absorption band appears at about 1705-1695
cm.sup.-1, attributable to the formation of C.dbd.O bonds of the imide
type.
The method to determine the dispersing activity or the anti-flocculating
activity of the imide-terpolymer is based on its dispersion power for
asphaltenes contained in a hydrocarbon oil. The asphaltenes are obtained
by air-oxidizing a naphthenic oil in the presence of traces of an iron
salt as catalyst. The oxidation is preferably effected at 175.degree. C.
for about 72 hours by passing an air stream through the naphthenic oil, so
as to form settlings which can be separated by centrifugation. 2% by
weight of this settling are added to a hydrocarbon oil solution containing
0.5% b.w. of terpolymer; after stirring of the mixture between 90.degree.
and 150.degree. C. for 2 hours, the resultant colored solution remains
clear when standstill, which confirms the dispersant activity of the
terpolymer with respect to the asphaltenes.
300 ppm of the imide-terpolymer is added to an Indian crude oil heated to
60.degree. C.; the pour point is decreased from +33.degree. C. to
+18.degree. C.
EXAMPLE 12
A solution of 1.2 g of dicumyl peroxide in 20 cc of diisopropylbenzene is
added in 2 hours to a solution of 66 g (20.37.times.10.sup.-2 mole) of
stearyl acrylate, 18 g (9.78.times.10.sup.-2 mole) of 2-ethylhexyl
acrylate, 12 g (10.71.times.10.sup.-2 mole) of diisobutylene and 31 g
(13.59.times.10.sup.-2 mole) of dibutyl maleate in 500 cc of
diisopropylbenzene heated to 120.degree. C.; heating is continued at
120.degree. C. for 4 hours.
The average molecular weight of the product obtained by settling of the
mixture in methyl alcohol is about 7,000.
A sample of the crude solution in diisopropylbenzene is added to a residual
fuel oil (a vacuum residue of a desulfurized Arabian oil) having a pour
point of about -4.degree. C.; in the presence of 300 ppm of terpolymer,
the pour point is decreased to about -15.degree. C.
EXAMPLE 13
A mixture of 24 g (21.43.times.10.sup.-2 mole) of diisobutylene and 40 g
(21.97.times.10.sup.-2 mole) of the maleimide obtained by reacting maleic
anhydride with dimethylaminopropylamine in 500 cc of a diesel oil having a
distillation range from 150.degree. to 370.degree. C. is heated to
90.degree. C.; 500 cc of a diesel oil solution containing 32 g
(9.87.times.10.sup.-2 mole) of stearyl acrylate, 50 g
(20.83.times.10.sup.-2 mole) of lauryl acrylate and 1.2 g of
azobisisobutyronitrile are added progressively thereto. When the addition
has been completed, stirring of the reaction mixture is continued at
90.degree. C. for 4 hours.
A sample of the resultant solution is added to the Mandji atmospheric
residuum, as used in example 10, having a pour point o | | |
