[0001] Mineral oils containing wax therein have the characteristic of becoming less fluid
as the temperature of the oil decreases. This loss of fluidity is generally due to
increase in viscosity and/or the crystallisation of the wax into plate-like crystals
which eventually form a spongy mass entrapping the oil therein.
[0002] It has long been known that various compositions act as wax crystal modifiers and
pour depressants when blended with waxy mineral oils. These compositions modify the
size and shape of wax crystals and reduce the adhesive forces between the wax and
oil in such a manner as to permit the oil to remain fluid at a lower temperature.
[0003] Various pour point depressants have been described in the literature and several
of these are in commercial use. For example, U.S. Pat. No. 3,048,479 teaches the use
of copolymers of ethylene and C
3-C
5 vinyl esters, e.g. vinyl acetate as pour depressants for fuels, specifically heating
oils, diesel and jet fuels. Hydrocarbon polymeric pour depressants based on ethylene
and higher alpha-olefins, e.g. propylene, are also known. U.S. Patent 3,961,916 teaches
the use of a mixture of copolymers, one of which is a wax crystal nucleator and the
other a growth arrestor to control the size of the wax crystals.
[0004] Similarly United Kingdom Patent 1263152 suggests that the size of the wax crystals
may be controlled by using a copolymer having a lower degree of side chain branching.
[0005] It has also been proposed in for example United States Patent 1469016 that the copolymers
of di-n-alkyl fumarates and vinyl acetate which have previously been used as pour
point depressants for lubricating oils may be used as co-additives with ethylene/vinyl
acetate copolymers in the treatment of distillate fuels with high final boiling points
to improve their low temperature flow properties. According to United Kingdom Patent
1469016 these polymers may be C
6 to C
18 alkyl esters of unsaturated C
4 to C
8 dicarboxylic acids particularly lauryl fumarate; lauryl-hexadecyl fumarate. Typically
the materials used are mixed esters with an average of about 12 carbon atoms (Polymer
A).
[0006] Our European Patent Applications 85301047, 85301048, 85301675 and 85301676 suggest
that the effectiveness of these type of materials may be improved if the copolymers
containing very specific alkyl groups such as specific di-n-alkyl fumarate/vinyl acetate
copolymers. For example, polymers in which the average number of carbon atoms in the
alkyl groups in the copolymer must be from 12 to 14 and that it must contain no more
than 10 wt.% of copolymer in which the alkyl groups contains more than 14 carbon atoms
and preferably no more than 20 wt.% of copolymer in which the alkyl group contains
fewer than 12 carbon atoms have been found to be particularly effective in certain
fuels and polymers with specific longer alkyl qroups particularly effective in other
fuels.
[0007] Our European Patent Application 0061895 A
2 describes the use of polyoxyalkylene esters, ethers, ester/ethers and mixtures thereof
containing at least two C
10 to C
30 linear saturated alkyl groups and a polyoxyalkylene glycol aroup of molecular weight
100 to 5000 the alkyl group in the polyoxyalkylene glycol containing from 1 to 4 carbon
atoms as additives for distillate fuels.
[0008] It has also been shown that in many instances using mixtures of two types of additive
will give a synergistic improvement in cold temperature flow properties especially
in distillate fuels. Mixinq can however lead to problems of additive interaction sometimes
leading to a reduction in their effectiveness which can cause serious problems for
the refiner who may frequently wish to mix large quantities of fuels from different
sources and containing different additives for storage purposes an aim of the present
invention is to reduce this problem.
[0009] We have now found that polyoxyalkylene glycol groups may be incorporated into an
unsaturated ester copolymer to provide an effective low temperature flow improver
for hydrocarbons especially distillate fuels although they may be used in heavy fuels,
residual fuels, crude oils and as pour depressants in lubricating oils. The unsaturated
ester copolymer into which the polyoxyalkylene group is incorporated may be the types
previously proposed as flow improvers for middle distillate fuels. We have also found
that when these copolymers are used in distillate fuels the problem of adverse interaction
with other additives such as ethylene vinyl acetate copolymers may be reduced.
[0010] The present invention therefore provides the use for improvinq the flow properties
of liquid hyrocabon fuel oil of an additive comprising a polymer or copolymer of an
ethylenically unsaturated ester of weight averaae molecular weiqht from 1000 to 200,000
containinq from 0.1% to 50
% by weiqht of polyoxyalkylene groups of molecular weight from 100 to 5000.
[0011] The polymers of the present invention are preferably used as additives for distillate
fuels they are preferably used in an amount from 0.0001 to 5 wt.% based on the weiqht
of the distillate petroleum fuel oil and the present invention also includes distillate
fuel containin
q such an additive.
[0012] The polymers used in the present invention preferably have a weiqht average molecular
weiqht in the ranqe of 1000 to 100,000, preferably 20,000 to 70,000 as measured, for
example, by Gel Permeation Chromatography, calibrated against polystyrene molecular
weight standards.
[0013] The unsaturated esters of the present invention may be derived from ethylenically
unsatured mono, di or polycarboxylic acids or mixtures thereof and may be obtained
from unsaturated esters or mixtures thereof with other ethylenically unsaturated monomers
such as ethylene, propylene or butene. Examples of dicarboxylic acid esters useful
for preparinq the polymer can be represented by the qeneral formula:

wherein R
1 and R
2 are hydrogen or a C
1 to C
4 alkyl group,
e.g., methyl, R
3 is a C
8 to C
18 average, the average preferred depending upon the use to which the polymer is to
be put. R
3 may be a mixture of a broad range of alkyl groups such as those used in U.K. patent
1469016 for use as a lubricating oil pour depressant or the specific monomer range
of our European Patent Applications 85301047, 85301048, 85301675 and 85301676 for
use as distillate additives where they can not only improve low temperature flow and
filterability but also lower the cloud point of the fuel and R
4 is COOR
3, hydrogen or a C
1 to C
4 alkyl group. Where these types of unsaturated esters are used as raw materials for
the production of the polymers of the present invention the polyoxyalkylene group
may be incorporated into the molecule during the esterification of the carboxylic
acid to produce the ester described above. For example the polyethylene alycol may
be mixed with the alcohol R
30H in the appropriate ratio and used to esterify for example Fumaric acid. The esters
of the above formula may be homopolymerised or copolymerised with other ethylenically
unsaturated monomers such as short chain unsaturated esters for example vinyl esters
such as vinyl acetate, vinyl propionate and vinyl butyrate and alkyl acrylates and
alkyl methacrylates.
[0014] Typical copolymers of the type described above may be obtained by the copolymerisation
of a dicarboxylic acid mono or di- ester monomers such as dialkyl fumarates with various
amounts, e.q., 5 to 70 mole %, of other unsaturated esters or olefins. Such other
esters include short chain alkyl esters having the formula:

where R
1 is hydro
qen or a C
1 to C
4 alkyl group, R"' is -COOR"" or -OOCR"" where R"" is a C
1 to C
5 alkyl aroup branched or unbranched, and R"' is R" or hydrogen. Examples of these
short chain esters are methacrylates, acrylates, fumarates and maleates the vinyl
esters such as vinyl acetate and vinyl propionate being preferred. More specific examples
include methyl methacrylate, isopropenyl acetate and isobutyl acrylate.
[0015] Our preferred copolymers of this type contain from 40 to 60 mole % containing the
polyoxyalkylene moiety fumarate and 60 to 40 mole % of vinyl acetate.
[0016] These ester polymers are aenerally prepared by polymerisinq the ester monomers in
a solution of hydrocarbon solvent such as heptane, benzene, cyclohexane, or white
oil, at a temperature generally in the range of from 20°C to 150°C. and usually promoted
with a peroxide or azo type catalyst such as benzoyl peroxide azodiisobutyonitrile
under a blanket of an inert qas such as nitroaen or carbon dioxide in order to exclude
oxygen.
[0017] An alternative method for incorporating the polyoxyalkylene group into the ester
copolymers of the present invention is to copolymerise the above described ethylenically
unsaturated esters with an ethylenically unsaturated ester for the formula

Where R is an ethylenically unsaturated hydrocarbyl group and R' is a polyoxyalkylene
group. Examples of such esters include polyethylene glycol mono or di-oleate, polyethylene
glycol mono or di-cinamate, polyethylene qlycol acrylates etc. For example di-hexadecyl
fumarate, vinyl acetate and the di ester of oleic acid and polyoxyethylene glycol
of molecular weight 600 may be copolymerised to give a copolymer of the invention
[0018] Alternatively the polyoxyalkylene group may be incorporated into the ester polymer
by producing polymers containing free acid groups and then esterifying with the polyoxyalkylene
alcohol or glycol. For example copolymers of maleic anhydride with other unsaturated
materials such as vinyl esters, dialkyl fumarates styrene or olefines may be esterified
with the polyoxyalkylene alcohol or glycol. The polyoxyalkylene alcohol used may itself
be a mono-alcohol the other end of the qroup being etherified or esterified so as
to introduce a further desirable group in the polymer chain. The polyoxyalkylene alcohol
or glycol may be mixed with other alcohols especially the straight chain alkyl alcohols
when the products are to be used as additives for distillate fuels.
[0019] Examples of the polyoxyalkylene alcohols that may be used include esters, ethers
or ester/ethers of the general formula

Where R is Hydro
qen, -Alkyl,

[0020] A is the polyoxyalkylene seqment in which the alkylene
qroup has 1 to 4 carbon atoms such as polyoxymethylene, polyoxyethylene or polyoxytrimethylene.
It is preferred that the polyoxyalkylene segment itself has a molecular weiaht of
about 100 to 5000.
[0021] Examples of suitable alcohols and glycols especially when the materials are to be
used as additives for distillate fuels are the substantially linear polyethylene qlycols
(PEG) and polypropylene qlycols (PPG) havinq a molecular weiqht of about 100 to 5,000
preferably about 200 to 2,000. The monoesters of these glycols may be used and esters
of fatty acids containing about 1-30 preferably 2 to 30 carbon atoms are preferred
and it is preferred to use a C
18-C
24 fatty acid, especially behenic acid or mixtures of stearic and behenic acids. These
esters may also be prepared by esterifying polyethoxylated fatty acids or polyethoxylated
alcohols, for example the mono methyl ether of a PEG may be used or a polyethoxylated
fatty alcohol such as the commercially available "Brij" materials. A particularly
preferred compound for use as a distillate fuel flow improver especially in narrow
boilinq distillates is a copolymer of vinyl acetate with an eauimolar amount of a
fumarate ester prepared by esterifyin
q fumaric acid with a mixture of from at least 95 mole % of a mixture of C
12/C
14 strai
qht chain alcohols and up to 5 mole % of polyethylene qlycol of molecular weiqht 600.
[0022] Alternatively an ester polymer or copolymer containing free carboxylic acid or hydroxy
groups may be reacted with ethylene or propylene oxide to produce the materials of
this invention.
[0023] The compounds of the present invention may be used as additives to improve the low
temperature properties of hydrocarbon fuels such as crude oils, residual fuels and
distillate fuels where they lower the pour point, control wax crystal size to improve
low temperature filterability and can in some instances lower the cloud point of the
fuel. By distillate fuels we mean those fuels
qenerally used for diesel vehicles and heating oils especially domestic heating oils
generally boiling in the range 120°C to 500°C more particularly 160°C to 400°C. In
addition when used in some distillate fuels they have less of a tendency for adverse
interaction with other distillate additives than with similar additives which do not
contain the polyoxyalkylene group. The compounds may be used on their own but we have
found that in distillate fuels they are particularly effective when used in combination
with other additives previously proposed for improving the cold flow properties of
distillate fuels generally.
[0024] The additives of the present invention may be used with the polyoxyalkylene esters,
ethers, ester/ethers and mixtures thereof, containing at least two C
10 to C
30 linear saturated alkyl groups and a polyoxyalkylene qlycol of molecular weight 100
to 5,000 preferably 200 to 5,000, the alkyl group in said polyoxyalkylene glycol containing
from 1 to 4 carbon atoms. These materials form the subject of European Patent Publication
0061895 A2. Examples of suitable coadditives of this typeare the reaction product
of glycols generally the substantially linear polyethylene glycols (PEG) and polypropylene
glycols (PPG) with fatty acids containing about 10-30 preferably 18 to 24 carbon atoms,
especially behenic acid or mixtures of stearic and behenic acids, the esters may also
be prepared by esterifying polyethoxylated fatty acids or polyethoxylated alcohols.
Esters obtained by reacting fatty acids with polyalkoxylated amines or ammonia may
also be used.
[0025] The polymers and copolymers of this invention when used as fuel additives especially
distillate fuels may also be used with the ethylene unsaturated ester copolymer flow
improvers. The unsaturated monomers which may be copolymerized with ethylene, include
unsaturated mono and diesters of the general formula:

wherein R
3 is hydrogen or methyl; R
2 is a -OOCR
5 qroup wherein R
5 is hydrogen or a C
1 to C
28, more usually C
1 to C
17 and preferably a C
1 to C
8, straight or branched chain alkyl group; or R
2 is a -COOR
S group wherein R
5 is as previously described but is not hydrogen and R
4 is hydroqen or -COOR
S as previously defined. The monomer, when R
2 and R
4 are hydrogen and R
2 is -OOCR
5, includes vinyl alcohol esters of C
1 to C
29, more usually C
1 to C
18, monocarboxylic acid, and preferably C
2 to C
5 monocarboxylic acid. Examples of vinyl esters which may be copolymerised with ethylene
include vinyl acetate, vinyl propionate and vinyl isobutyrate, vinyl acetate being
the preferred vinyl ester. We prefer that the copolymers contain from 20 to 40 wt.%
of the vinyl ester more preferably from 25 to 35 wt.% vinyl ester. They may also be
mixtures of two copolymers such as those described in United States Patent 3961916.
[0026] It is preferred that these copolymers have a number average molecular wei
qht as measured by vapor phase osmometry (VPO) of 1000 to 6000 preferably 1000 to 4000.
[0027] Our polymers and copolymers may also be used in distillate fuels in combination with
polar compounds, either ionic or nonionic, which have the capability in fuels of acting
as wax crystal growth inhibitors. Polar nitrogen containing compounds have been found
to be especially effective when used in combination with the
qlycol esters, ethers or ester/ethers and such three component mixtures are within
the present invention. These polar compounds are generally the C
20-C
300 preferably C
20-C
100 amine salts and/or amides formed by reaction of at least one molar proportion of
hydrocarbyl substituted amines with a molar proportion of hydrocarbyl acid having
1-4 carboxylic acid groups or their anhydrides; ester/amides may also be used. These
nitrogen compounds are described in U.S. Patent 4,211,534. Suitable amines are usually
long chain C
12-C
40 primary, secondary, tertiary or quaternary amines of mixtures thereof but shorter
chain amines may be used provided the resulting nitrogen compound is oil soluble and
therefore normally containing about 20 to 300 total carbon atoms. The nitrogen compound
should also have at least one straight chain C
S-C
40 alkyl segment.
[0028] Suitable amines include primary, secondary, tertiary or quaternary, but preferably
are secondary. Tertiary and quaternary amines can only form amine salts. Examples
of amines include tetradecyl amine, cocoamine, hydrogenated tallow amine and the like.
Examples of secondary amines include dioctadecyl amine, methyl-behenyl amine and the
like. Amine mixtures are also suitable and many amines derived from natural materials
are mixtures. The preferred amine is a secondary hydrogenated tallow amine of the
formula HNR
lR
2 wherein R
1 and R
2 are alkyl groups derived from hydroqenated tallow fat composed of approximately 4%
C
14, 31% C
16, 59% C
18.
[0029] Examples of suitable carboxylic acids for preparing these nitrogen compounds (and
their anhydrides) include cyclohexane dicarboxylic acid, cyclohexene dicarboxylic
acid, cyclopentane dicarboxylic acid, dialpha-naphthyl acetic acid, naphthalene dicarboxylic
acid and the like. Generally these acids will have about 5-13 carbon atoms in the
cyclic moiety. Preferred acids useful in the present invention are benzene dicarboxylic
acids such as phthalic acid, terephthalic acid, and ortho-phthalic acid. Ortho-phthalic
acid or its anhydride is the particularly preferred embodiment.
[0030] It is preferred that the nitrogen containing compound have at least one straight
chain alkyl segment extending from the compound containing 8-40, preferably 8-24 carbon
atoms. Also at least one ammonium salt, amine salt or amide linkage is required to
be present in the molecule. The particularly preferred amine compound is that amide-amine
salt formed by reacting 1 molar portion of phthalic anhydride with 2 molar portions
of di-hydrogenated tallow amine. Another preferred embodiment is the diamide formed
by dehydrating this amide-amine salt.
[0031] Other amine derivatives which may be used as co-additives are oil soluble amine carboxylic
acid salts and/or amides e.g. trioctylamine myristate or behenate. Reaction products
of polyamines with fatty carboxylic acids such as the product of reacting tetraethylene
pentamine with stearic or behenic acid may be used as may fatty amides themselves.
The copolymers may be used in combination with one or more additives of the type described
above.
[0032] The relative proportions of additives used in the preferred mixtures of the invention
are from 0.5 to 20 parts by weight of the ester polymer containina the polyoxyalkylene
group to 1 part of the other additives. The total amount of additive used will depend
upon the particular fuel but generally we use from 0.0001% to 5% by weight of the
fuel.
[0033] The additive systems of the present invention may conveniently be supplied as concentrates
in oil for incorporation into the bulk fuel. These concentrates may also contain other
additives as required. These concentrates preferably contain from 3 to 75 wt %, more
preferably 3 to 60 wt %, most preferably 10 to 50 wt.% of additive preferably. Such
concentrates are also within the scope of the present invention.
[0034] The present invention is illustrated by the following Examples in which the effectiveness
of the additives of the present invention as pour point depressants and filterability
improvers in distillate fuels were compared with other similar additives in the Cold
Filter Plugging Point Test (CFPPT) which is carried out by the procedure described
in detail in "Journal of the Institute of Petroleum", Volume 52, Number 510, June
1966, pp. 173-185. This test is desiqned to correlate with the cold flow of a middle
distillate fuel in automatic diesels.
[0035] In brief, a 40 ml sample of the oil to be tested is cooled in a bath which is maintained
at about -34°C to give non-linear cooling at about 1°C/min. Periodically (at each
one deqree Centriqrade drop in temperature starting from at least 2'C above the cloud
point) the cooled oil is tested for its ability to flow through a fine screen in a
prescribed time period usina a test device which is a pipette to whose lower end is
attached an inverted funnel which is positioned below the surface of the oil to be
tested. Stretched across the mouth of the funnel is a 350 mesh screen having an area
defined by a 12 millimetre diameter. The periodic tests are each initiated by applyin
q a vacuum to the upper end of the pipette whereby oil is drawn through the sceen up
into the pipette to a mark indicating 20 ml of oil. After each successful passage
the oil is returned immediately to the CFPP tube. The test is repeated with each one
deqree drop in temperature until the oil fails to fill the pipette within 60 seconds.
This temperature is reported as the CFPP temperature. The difference between the CFPP
of an additive free fuel and of the same fuel containing additive is reported as the
CFPP depression by the additive. A more effective additive flow improver gives a
qreater CFPP depression at the same concentration of additive.
Example 1
[0036] The fuels used in thes Example were:
[0037] The additives used were
Additive 1 a copolymer of a mixed C12/C14 fumarate ester obtained by reaction of 50:50 molar mixture of normal C12 and C14 alcohols with fumaric acid and solution copolymerisation with vinyl acetate in 1
to 1 mole ratio at 60°C using azo diisobutyonitrile as catalyst.
Additive 2 the dihebenate ester of polyethylene qly col of molecular weight 600.
Additive 3 the dibehenate ester of polyethylene glycol of molecular weight 400.
Additive 4 was the same as Additive 1 except that 2.5 mole % of a polyethylene qlycol
of 600 average molecular weight was included in the C12/C14 alcohol mixture used to esterify the fumaric acid and the polymerisation was carried
out at 80°C.
Additive 5 was the same as Additive 4 except 2.5 mole % of the monomethyl ether of
polyethylene glycol of 750 molecular weight was used in place of the polyethylene
qlycol of 600 molecular weiqht.
[0038] The CFPP depressions obtained in the fuels when treated with these additives and
mixtures thereof were as follows:

[0039] In each instance showing a greater reduction in the CFPP temperature when the polyoxyalkylene
segment is present in the molecule.
Example 2
[0040] The Additives of Example 1 were tested in the following fuels.

[0041] And the amount of additive (a 2:1 by weight mixture of Additives 1 or 5 with Additive
3) required to reach the target CFPP was measured with the following results

Example 3
[0042] The CFPP depressions obtained usinq 2:1 mixtures of Additives 1, 4 or 5 with 3 were
found to be as follows

Example 4
[0043] Additives of the present invention were used in fuel G together with an ethylene
vinyl acetate (EVA) copolymer according to United Kinqdom Patent 1263152 containinq
36 wt % vinyl acetate and having a number avera
qe molecular weight of 2000 as measured by Vapor Phase Osmometry.
[0044] The other additives used were Additive 1 of Example 1.
Additive 6 was the same as Additive 1 except that 5 mole % of a poly-ethylene glycol
of 600 molecular weight dioleate was added to the C12/C14 alcohol mixture used to esterify the fumaric acid.
Additive 7 was the same as Additive 1 except that the dialkyl fumarate was obtained
from the following mixture of alcohols
45 moles n-C12 alcohol 45 moles n-C14 alcohol 10 moles n-C16 (CH2-CH2O)220-OH
Additive 8 was the same as Additive 6 except that 2 mole % of the polyethylene glycol
of 600 molecular weight was used.
[0045] The CFPP values obtained were as follows:

Example 5
[0046] The effect of the amount of additive used on the CFPP values for Fuels E, F, G and
I was determined using the following Additive Mixtures

[0047] The results are shown in the graphs Figures 1 to 4 Figures 3 and 4 also including
results obtained using the same treat rate of the EVA copolymer used in Example 4
alone .
Example 6
[0048] The compounds of the present invention were tested as pour depressants in a solvent
neutral lubricatin
q oil. The polymers were prepared by the process described above from an equimolar
amount of the fumarate ester prepared from the following mixture of alcohols.

and vinyl acetate (Additive 9) and a similar polymer in which the alcohol mixture
contains 2.5 mole% of the polyethylene glyucol of 750 molecular weight used in Additive
5 (Additive 10).
[0049] The pour points were measured according to the ASTM D 97 method with the following
results.

Example 7
[0050]
Additive 9 was the same as Additive 1 except that a commercial alcohol mixture sold
as Dobanol 25 was used instead of the mixture of C12 and C14 alcohols. Dobanol 25 is a mixture of
20 wt.% C12 alcohols 30 wt.% C13 alcohols 30 wt.% C14 alcohols 20 wt.% C15 alcohols
80 wt.% of which are normal alcohols and 20 wt.% with a methyl branch at the 1 position.
Additive 10 was the same as Additive 9 except that a mixture of 1.975 moles of Dobanol
25 and 0.025 moles of polyethylene qlycol of molecular weiaht 750 were used.
[0051] These Additives were tested as 4:1 ratio mixtures of Additive with Additive 3 in
[0053] Fuel J which has an untreated CFPP of -5°C and the following ASTM D-96 distillation.

with the followina results

Example 8
[0054] Additives were tested in Fuel K which had a cloud point of +5°C and the following
ASTM D-96 distillation

and the appearance of the fuel recorded at -5°C after cooling at 1'C per hour.
[0055] 1000 ppm of the additives were used as 4:1 mixtures and the results were as follows:

Example 9
[0056] Additive 11 was the same as Additive 1 except that 10- mole % of the C
12/C
14 alcohol was replaced by the monomethyl ether of polyethylene
qlycol of molecular weight 750.
[0057] The Additives were tested in a blend of 50 wt.% of Fuel L have an untreated CFPP
of -2'C and ASTM-D-96 distillation of

and 50 wt.% of a Fuel D containing 200 ppm of an ethylene vinyl acetate copolymer
of 32 wt.% vinyl acetate to give a CFPP of -9°C. The amount of additive required to
qive the blend a CFPP of -9°C was determined to be as follows

[0058] The tests were repeated using as the fuel a mixture of 50 wt.% of Fuel J and 50 wt.%
of Fuel M containing 200 ppm of the ethylene vinyl acetate copolymer.
[0059] Fuel M had an untreated CFPP of -4°C and an ASTM D-96 distillation of

[0060] The amount of additive required to give a CFPP of -9°C was found to be as follows

1 The use for improvinq the flow properties of liquid hydrocarbons of a polymer or copolymer of weiqht average
molecular weight from 1000 to 200,000 prepared from an ethylenically unsaturated ester
and containing from 0.1 5 to 50% by weight of polyoxyalkylene qroups of molecular
weiqht from 100 to 5000.
2 The use accordinq to Claim 1 in which the ethylenically unsaturated ester is a fumarate
ester.
3 The use accordinq to Claim 2 in which the polyoxyalkylene qroup is present by esterifyinq the fumaric acid with an alcohol mixture containing a polyoxyalkylene alcohol or
glycol.
4 The use according to Claim 2 or Claim 3 in which the fumarate ester is copolymerised
with another ethylenically unsaturated ester.
5 The use according to Claim 4 in which the other ethylenically unsaturated ester
is vinyl acetate.
6 The use accordinq to Claim 1 in which the polymer or copolymer is prepared by copolymerising
an unsaturated ester of formula

where R is an ethylenically unsaturated hydrocarbon group and R' is a polyoxyalkylene
qroup with another ethylenically unsaturated monomer.
7 The use accordinq to Claim 6 in which the other ethylenically unsaturated monomer
is a vinyl ester.
8 The use according to Claim 1 in which the polymer or copolymer is prepared by esterifyinq a polymer containinq free carboxylic acid aroups with a polyoxyalkylene alcohol or
qlycol.
9 The use according to Claim 8 in which the poly-. oxyalkylene alcohol or glycol is
used in admixture with other alcohols.
10 The use accordin
q to any of the precedinq claims in combination with one or more of the additives selected
from the croup consisting of
(i) ethylene unsaturated ester copolymer flow improvers
(ii) polyoxyalkylene ester ethers, ester/ethers and mixtures thereof
(iii) ionic or nonionic polar compounds
11 The use accordinq to any of the precedinq claims in which the hydrocarbon fuel
is a distillate petroleum fuel.
12 A distillate-petroleum fuel containing from 0.0001 to 5 wt.% based on the weiqht
of the distillate petroleum fuel oil of polymer or copolymer of weight average molecular
weight from 1000 to 200,000 prepared from an ethylenically unsaturated ester and containing
from 0.1 to 50 wt.% of polyoxyalkylene groups of molecular weiqht from 100 to 5000.
13 A distillate petroleum fuel accordinq to Claim 12 in which the ethylenically unsaturated
ester is a fumarate ester.
14 A distillate petroleum fuel according to Claim 13 in which the polyoxyalkylene
qroup is present by esterifying the fumaric acid with an alcohol mixture containing
a polyoxyalkylene alcohol or glycol.
15 A distillate petroleum fuel according to Claim 13 or Claim 14 in which the fumarate
ester is copolymerised with another ethylenically unsaturated ester.
16 A distillate petroleum fuel according to Claim 15 in which the other ethylenically
unsaturated ester is vinyl acetate.
17 An additive concentrate comprising an oil solution containing from 3 to 75 wt.%
based on the weight of the concentrate of polymer or copolymer of weight averaqe molecular
weight from 1000 to 200,000 prepared from an ethvlenically unsaturated ester and containing from 0.1 to 50 wt.% of polyoxyalkylene qroups of molecular weiaht from 100 to 5000 optionally together with other additives.
Claims for the following Contracting State(s) : AUSTRIA
1 A process for improving the flow properties of liquid hydrocarbons comprising adding
thereto a polymer or copolymer of weight average molecular weight from 1000 to 200,000
prepared from an ethylenically unsaturated ester and containing from 0.1 5 to 50%
by weight of polyoxyalkylene groups of molecular weiqht from 100 to 5000.
2 A process according to Claim 1 in which the ethylenically unsaturated ester is a
fumarate ester.
3 A process according to Claim 2 in which the polyoxyalkylene group is present by
esterifying the fumaric acid with an alcohol mixture containing a polyoxyalkylene
alcohol or glycol.
4 A process according to Claim 2 or Claim 3 in which the fumarate ester is copolymerised
with another ethylenically unsaturated ester.
5 A process according to Claim 4 in which the other ethylenically unsaturated ester
is vinyl acetate.
6 A process according to Claim 1 in which the polymer or copolymer is prepared by
copolymerising an unsaturated ester of formula

where R is an ethylenically unsaturated hydrocarbon 25 group and R' is a polyoxyalkylene
qroup with an admixture with other alcohols.
7 A process accordinq to Claim 6 in which the other ethylenically unsaturated monomer is a vinyl ester.
8 A process according to Claim 1 in which the polymer or copolymer is prepared by
esterifyinq a polymer containing free carboxylic acid groups with a polyoxyalkylene
alcohol or qlycol.
9 A process according to Claim 8 in which the polyoxyalkylene alcohol or glycol is
used in admixture with other alcohols.
10 A process according to any of the preceding claims in combination with one or more
of the additives selected from the group consisting of
(i) ethylene unsaturated ester copolymer flow improvers
(ii) polyoxyalkylene ester ethers, ester/ethers and mixtures thereof
(iii) ionic or nonionic polar compounds
11 A process according to any of the preceding claims in which the polymer or copolymer
is added as a concentrate comprising an oil solution containing from 3 to 75 wt.% based on the weiqht of the concentrate of polymer or copolymer of weight average
molecular weight from 1000 to 200,000 prepared from an ethylenically unsaturated ester
and containing from 0.1 to 50 wt.% of polyoxyalkylene groups of molecular 20 weight
from 100 to 5000 optionally together with other additives.
12 A process according to any of the preceding claims in which the liquid hydrocarbon
is a petroleum distillate fuel.