Use of crosslinked polymers for lowering the cold filter plugging point of fuels

Abstract

The present invention concerns the use, for lowering the cold filter plugging point of a fuel composition, of one or more crosslinked polymers comprising at least one unit of the following formula (I): in which R1 represents a hydrogen atom or a methyl group; E represents -O-CO-, or -CO-O- or -NH-CO- or -CO-NH-; and G represents a C1 to C34 alkyl group; said copolymer having a crosslinking rate of between 0.5 mol% and 30 mol%. The invention also concerns additive compositions containing such a polymer, and fuel compositions with such polymers as additives, in combination with a cold flow improver (CFI) chosen from the copolymers and terpolymers of ethylene and vinyl and / or acrylic ester(s).

Description

[0001] The present invention relates to the use of particular crosslinked polymers to lower the filterability limit temperature of fuels or combustibles during their storage and / or use at low temperature.

[0002] The present invention also relates to additive compositions (or "additive packages") containing these polymers, as well as fuel and combustible compositions additivated with such polymers in combination with a cold flow additive (CFI). STATE OF THE PRIOR ART

[0003] Fuels or combustibles containing paraffinic compounds, in particular compounds containing n-alkyl, iso-alkyl or n-alkenyl groups such as paraffinic waxes, are known to have deteriorated flow properties at low temperatures, typically below 0°C. In particular, middle distillates obtained by distillation from crude oils of petroleum origin such as diesel or heating oil are known to contain different quantities of n-alkanes or n-paraffins depending on their origin. These compounds tend to crystallize at low temperatures, blocking pipes, lines, pumps and filters, for example in the fuel systems of motor vehicles.In winter or when fuels or combustibles are used at temperatures below 0°C, the crystallization of these compounds can lead to a reduction in the flow properties of the fuels or combustibles and, consequently, cause difficulties during their transport, storage and / or use. The cold operability of fuels or combustibles is a very important property, particularly to ensure cold engine starting. If paraffins are crystallized at the bottom of the tank, they can be carried along during start-up in the fuel circuit and clog, in particular, the filters and pre-filters located upstream of the injection systems (pump and injectors). Similarly, for the storage of domestic fuel oils, if paraffins precipitate at the bottom of the tank, they can be carried along and obstruct the pipes upstream of the pump and the boiler feed system (nozzle and filter).

[0004] These problems are well known in the field of fuels and combustibles, and many additives or additive blends have been proposed and marketed to reduce the size of paraffin crystals and / or change their shape and / or prevent them from forming. The smallest possible crystal size is preferred because it minimizes the risk of filter plugging or clogging.

[0005] Common flow improvers known as cold flow improvers (CFIs) are generally co- and ter-polymers of ethylene and vinyl and / or acrylic ester(s), used alone or in a mixture. These cold flow improvers (CFIs), intended to lower the Filterability Limit Temperature (FLT), inhibit crystal growth at low temperatures by promoting the dispersion of paraffin crystals; these are, for example, polymers of ethylene and vinyl acetate and / or vinyl propionate (EVA or EVP), also commonly called FLT additives. This type of additive, very widely known to those skilled in the art, is systematically added to conventional middle distillates at the refinery outlet. These additivated distillates are used as diesel engine fuel or as heating fuel.Additional quantities of these additives can be added to fuels sold at service stations, in particular to meet the so-called Extreme Cold specifications.

[0006] To improve the TLF of distillates, it is known to add to these CFI additives additional additives or "boosters" having the function of acting in combination with the CFI additives so as to increase their effectiveness. The prior art describes such combinations of additives extensively.

[0007] By way of example, mention may be made of US patent 3,275,427 describing a middle distillate of a distillation cut between 177 and 400°C containing an additive consisting of 90 to 10% by mass of an ethylene copolymer comprising 10 to 30% of vinyl acetate units with a molar mass by weight of between 1000 and 3000 g.mol -1< and 10 to 90% by mass of a lauryl polyacrylate and / or a lauryl polymethacrylate with a molar mass by weight varying from 760 to 100,000 g.mol -1<.

[0008] Document EP0857776 proposes to use alkylphenol-aldehyde resins resulting from the condensation of alkylphenol and aldehyde in association with ethylene / vinyl ester copolymers or terpolymers, to improve the fluidity of mineral oils.

[0009] Patent application WO 2008 / 006965 describes the use of a combination of a homopolymer obtained from an olefinic ester of a carboxylic acid of 3 to 12 carbon atoms and a fatty alcohol comprising a chain of more than 16 carbon atoms and optionally an olefinic double bond and a cold flow additive (CFI) of the EVA or EVP type, to increase the effectiveness of the CFI additives by amplifying their effect on the TLF.

[0010] Patent application WO 2016 / 128379 describes the use, as a cold resistance additive for a fuel or combustible, of a block copolymer comprising: (i) a block A consisting of a chain of structural units derived from one or more α,β-unsaturated alkyl acrylate or methacrylate monomers, (ii) a block B consisting of a chain of structural units derived from one or more α,β-unsaturated monomers containing at least one aromatic nucleus.

[0011] This additive is particularly useful as a TLF booster in association with a cold flow additive (CFI).

[0012] Patent application EP 0 120 512 describes a paraffin-rich fuel composition containing as a pour point lowering additive a branched polymer obtained by copolymerization of: a monomer (A) comprising a C 14+ hydrocarbon chain; up to 10% by weight of a monounsaturated monomer (B) and from 0.01 to 1% by weight of a polyunsaturated monomer (C). It is not crosslinked.

[0013] Document US 3,222,282 describes additives consisting of crosslinked terpolymers obtained by copolymerization of a fatty alcohol ester and unsaturated dicarboxylic acid, of a C 2 -C 3 alkene ester with a C 1 -C 4 acid and of an unsaturated C 4 -C 5 acid anhydride or of a hydroxyalkyl acrylate of particular formula, and of 0.01 to 5% by weight of a crosslinking agent containing two allyl groups or one allyl group and one vinyl group. These polymers are essentially intended to increase the viscosity index of lubricating oils.

[0014] Document US 3,817,866 describes a polymeric additive intended to lower the pour point of heavy petroleum fractions containing macrocrystalline waxes, obtained by polymerization of a mixture of alkyl acrylates whose alkyl chains have at least 18 carbon atoms, with a crosslinking agent consisting of a diol dimethacrylate.

[0015] Due to the diversification of fuel and combustible sources, there is always a need to find new additives to lower the filterability limit temperature of fuels or combustibles.

[0016] This need is particularly important for fuels or combustibles comprising one or more paraffinic compounds, for example compounds containing n-alkyl, iso-alkyl or n-alkenyl groups exhibiting a tendency to crystallize at low temperature.

[0017] In particular, distillates used in fuels and combustibles are increasingly derived from more complex refining operations than those from direct distillation of petroleum, and can come in particular from cracking, hydrocracking, catalytic cracking and visbreaking processes. With the growing demand for diesel fuels, the refiner tends to introduce into these fuels more difficult to exploit cuts, such as the heavier cuts from cracking and visbreaking processes which are rich in long-chain paraffins.

[0018] In addition, synthetic distillates from gas processing such as those from the Fischer Tropsch process, as well as distillates resulting from the processing of biomass of plant or animal origin, such as NexBTL and distillates comprising esters of vegetable or animal oils have appeared on the market, and constitute a new range of products that can be used as a base for formulating fuels and / or domestic heating oils. These products also include long-chain paraffinic hydrocarbons.

[0019] In addition, we have seen the arrival of new crude oils on the market, much richer in paraffins than those commonly refined and whose filterability temperature of distillates from direct distillation was difficult to improve by conventional filterability additives like those previously mentioned.

[0020] It was found that the cold holding properties of distillates obtained by combining the old bases and these new sources were difficult to improve by adding conventional filterability additives, among other things due to the significant presence of long-chain paraffins and the complex distribution of paraffins in their composition. In fact, discontinuous distributions of paraffins were noted in these new combinations of distillates, in the presence of which the known filterability additives are not always sufficiently effective.

[0021] There is therefore a need to adapt cold-holding additives to these new types of fuel bases, which are considered particularly difficult to process.

[0022] The present invention applies to fuels and combustibles containing not only conventional distillates such as those from the direct distillation of crude oils, but also to bases from other sources, such as those described above.

[0023] Thus, the aim of the present invention is to propose new additives and concentrates containing them which can advantageously be used as additives to improve the cold resistance properties of these fuels or combustibles, during their storage and / or their use at low temperature, typically below 0°C.

[0024] The aim of the present invention is to propose new additives for fuels and combustibles, and concentrates containing such additives, acting on the Filterability Limit Temperature (FLT).

[0025] Finally, another object of the invention is to provide a fuel or combustible composition having improved cold resistance properties, in particular at temperatures below 0°C, preferably below -5°C. SUBJECT OF THE INVENTION

[0026] The applicant has now discovered that particular crosslinked homopolymers or copolymers, as described below, possess unexpected properties for lowering the filterability limit temperature of fuel and combustible compositions, including those which are particularly difficult to process.

[0027] The subject of the present invention is thus the use, for lowering the filterability limit temperature of a fuel or combustible composition, of one or more crosslinked polymers comprising at least one unit of the following formula (I): in which R 1 represents a hydrogen atom or a methyl group, E is a -CO-O- group linked to the vinyl carbon by the carbon atom, G is a linear or branched acyclic alkyl radical of C 6 to C 24 , said copolymer having a crosslinking rate, corresponding to the quantity in moles of crosslinking agent relative to the total quantity in moles of monomers in the polymer, crosslinking agent not included, comprised in the range from 0.5% to 30%, the crosslinking agent of the polymer being chosen from diacrylates and dimethacrylates of the following formula (III): with R representing a hydrocarbon chain comprising from 2 to 16 carbon atoms, which may be interrupted by one or more heteroatoms chosen from N and O, and which may be substituted by one or more -OZ groups with Z representing a hydrogen atom or a C 1 to C 4 alkyl radical, and R 2 and R 3 representing, independently of one another, a hydrogen atom or a methyl group, characterized in that said polymer is used in combination with at least one cold-thinning additive chosen from copolymers and terpolymers of ethylene and vinyl and / or acrylic ester(s).

[0028] According to the invention, the polymer defined above is used as a so-called “TLF booster” additive, i.e. in combination with a flow improvement additive or cold flow improver (CFI), the performance of which it improves.

[0029] The invention also relates to an additive composition comprising such a polymer in association with a cold-thinning additive as described below, as well as an additive concentrate comprising such a composition. The cold-thinning additive is chosen from copolymers and terpolymers of ethylene and vinyl and / or acrylic ester(s), alone or as a mixture.

[0030] The invention also relates to a fuel or combustible composition, comprising: (1) at least one hydrocarbon fraction from one or more sources chosen from the group consisting of mineral (preferably petroleum), animal, vegetable and synthetic sources, (2) at least one crosslinked polymer as defined above, and (3) at least one cold-thinning additive chosen from copolymers and terpolymers of ethylene and vinyl and / or acrylic ester(s).

[0031] Other objects, characteristics, aspects and advantages of the invention will appear even more clearly on reading the description and examples which follow.

[0032] In what follows, and unless otherwise indicated, the limits of a domain of values ​​are included in this domain, in particular in the expressions "between" and "ranging from ... to ...".

[0033] Furthermore, the expressions "at least one" and "at least" used in this description are respectively equivalent to the expressions "one or more" and "greater than or equal".

[0034] Finally, in a manner known per se, a CN compound is a compound containing N carbon atoms in its chemical structure. DETAILED DESCRIPTION The crosslinked polymer:

[0035] The invention uses a crosslinked polymer, comprising at least one unit of the following formula (I): in which R 1 represents a hydrogen atom or a methyl group, the E group is a -CO-O- group, E being linked to the vinyl carbon by the carbon atom.

[0036] The group G of formula (I) is a linear or branched acyclic alkyl radical of C 6 to C 24 , more preferably of C 8 to C 22 , and better still of C 12 to C 14 or of C 18 to C 22 . The embodiment in which the group G is a linear or branched acyclic alkyl radical of C 12 to C 14 is particularly preferred.

[0037] Examples that may be mentioned, without limitation, are alkyl groups such as octyl, decyl, dodecyl, 2-ethylhexyl, isooctyl, isodecyl and isododecyl, C 14 alkyl groups, C 16 alkyl groups and C 18 alkyl groups.

[0038] The patterns correspond to those derived from monomers chosen from C6 to C24 alkyl acrylates and methacrylates, more preferably C8 to C22, and better still C12 to C14 or C18 to C22.

[0039] The crosslinked polymer can be a homopolymer or a copolymer.

[0040] In this case of a copolymer, the polymer according to the invention may comprise several (at least two) different units of formula (I) as described above and / or additional units, different from the units of formula (I) above.

[0041] Such additional units are preferably derived from polar monomers, such as in particular from one or more vinyl monomers bearing a polar substituent.

[0042] Preferred polar monomers include: 2-phenoxyethylacrylate: 1-vinylimidazole: N-vinylpyrrolidone:

[0043] The copolymer according to the invention advantageously contains at least 50 mol% of units of formula (I), preferably at least 70 mol%. Preferably, the copolymer contains from 50 to 80 mol% of units of formula (I).

[0044] When the polymer according to the invention is a copolymer, it can be chosen from block copolymers and random copolymers, preferably random copolymers.

[0045] The polymer according to the invention has the particularity of being crosslinked. The crosslinking rate, corresponding to the quantity in moles of crosslinking agent relative to the total quantity in moles of monomers of the polymer, crosslinking agent not included, is from 0.5% to 30%, preferably from 1% to 20%, more preferably from 2% to 10%, and better still from 3% to 6%.

[0046] The crosslinking agent is chosen from diacrylates and dimethacrylates of the following formula (III): with R representing a hydrocarbon chain comprising from 2 to 16 and preferably from 3 to 12 carbon atoms, which can be interrupted by one or more heteroatoms chosen from N and O, and which can be substituted by one or more -OZ groups with Z representing a hydrogen atom or a C 1 to C 4 alkyl radical, and R 2 and R 3 representing, independently of one another, a hydrogen atom or a methyl group.

[0047] As non-limiting examples of particularly preferred crosslinking agents, mention may be made of: 1,6 hexanediol dimethacrylate, of formula: di(ethylene glycol) dimethacrylate, of formula: glycerol dimethacrylate, of formula: 1,6 hexanediol diacrylate, of formula: di(ethylene glycol) diacrylate, of formula: 1,6 hexanediol ethoxylate diacrylate of formula:

[0048] The polymer used in the present invention can be obtained by homopolymerization or copolymerization of at least one monomer corresponding to the following formula (II): wherein R 1 , E and G are as defined above, the preferred variants of R 1 , E and G according to formula (I) described above also being preferred variants of formula (II).

[0049] The monomer of formula (II) is preferably chosen from C 6 to C 24 alkyl acrylates or methacrylates, more preferably C 8 to C 22 and better still C 12 to C 14 or C 18 to C 22, and even more preferably C 12 to C 14. The alkyl radical of the acrylate or methacrylate is linear or branched, cyclic or acyclic, preferably acyclic.

[0050] Among the alkyl (meth)acrylates which may be used as monomers in the manufacture of the polymer of the invention, mention may be made, as non-limiting examples: n-octyl acrylate, n-octyl methacrylate, n-decyl acrylate, n-decyl methacrylate, n-dodecyl acrylate, n-dodecyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, isooctyl acrylate, isooctyl methacrylate, isodecyl acrylate, isodecyl methacrylate, C 12 to C 14 or C 18 to C 22 alkyl acrylates and C 12 to C 14 or C 18 to C 22 alkyl methacrylates. Particularly preferred are C 12 to C 14 alkyl acrylates and C 12 to C 14 alkyl methacrylates, C 18 to C 22 alkyl acrylates and C 18 to C 22 alkyl methacrylates.

[0051] It is understood that it would not be a departure from the invention if the polymer useful in the invention were obtained from monomers different from those of formula (II) above, insofar as the final polymer corresponds to a crosslinked polymer as defined above. For example, it would not be a departure from the invention if the polymer were obtained by polymerization of different monomers, followed by post-functionalization. For example, the units of formula (I) can be obtained from acrylic acid, by transesterification reaction.

[0052] The polymer useful in the invention can be prepared according to any known polymerization process. The different polymerization and crosslinking techniques and conditions are widely described in the literature and fall within the general knowledge of those skilled in the art.

[0053] The polymerization is advantageously a controlled radical polymerization; for example, by atom transfer radical polymerization (ATRP); nitroxide-mediated radical polymerization (NMP); degenerative transfer processes such as degenerative iodine transfer polymerization (ITRP) or reversible addition-fragmentation chain transfer radical polymerization (RAFT);ATRP-derived polymerizations such as polymerizations using initiators for continuous activator regeneration (ICAR) or using activators regenerated by electron transfer (ARGET).

[0054] Reversible addition-fragmentation chain transfer (RAFT) is a living radical polymerization technique. RAFT was discovered in 1988 by the Australian scientific research organization CSIRO (J. Chiefari et al., Macromolecules, 1998, 31, 5559). RAFT quickly became the subject of intensive research by the scientific community as it allows the synthesis of macromolecules with complex architectures, including block, graft, comb, and star structures, while allowing control of the molecular mass of the resulting macromolecules (G. Moad et al., Aust. J. Chem, 2005, 58, 379). RAFT polymerization can be applied to a very wide range of vinyl monomers and under various experimental conditions, including for the preparation of water-soluble materials (CLMcCormick et al., Acc. Chem. Res. 2004, 37, 312). The RAFT process involves the classical radical polymerization of a substituted monomer in the presence of a suitable chain transfer agent (RAFT agent or CTA). Commonly used RAFT agents include thiocarbonylthio compounds such as dithioesters (J. Chiefari et al., Macromolecules, 1998, 31, 5559), dithiocarbamates (RTA Mayadunne et al., Macromolecules, 1999, 32, 6977; M. Destarac et al., Macromol. Rapid. Commun., 2000, 21, 1035), trithiocarbonates (RTA Mayadunne et al., Macromolecules, 2000, 33, 243), and xanthates (R. Francis et al., Macromolecules, 2000, 33, 4699), which effect polymerization by a reversible chain transfer process.The use of a suitable RAFT agent allows the synthesis of polymers with a high degree of functionality and exhibiting a narrow molecular weight distribution, i.e. a low polydispersity index (PDI).

[0055] Examples of RAFT radical polymerization descriptions include the following documents: WO1998 / 01478, WO1999 / 31144, WO2001 / 77198, WO2005 / 00319, WO2005 / 000924.

[0056] The crosslinked polymer useful in the invention advantageously has a weight-average molar mass (Mw) of between 10,000 and 100,000 g.mol -1< , preferably between 10,000 and 50,000 g.mol -1< , and more preferably between 11,000 and 35,000 g.mol -1< .

[0057] The crosslinked polymer useful in the invention advantageously has a number-average molar mass (Mn) of between 2,000 and 16,000 g.mol -1< .

[0058] Number and weight average molar masses are measured by size exclusion chromatography (SEC). Use:

[0059] The crosslinked polymer described above is used to lower the filterability limit temperature of a fuel or combustible composition, in particular, of a composition chosen from diesel oils, biodiesels, B x type diesel oils and fuel oils, preferably domestic fuel oils (DFO).

[0060] The filterability limit temperature, or TLF, is measured according to standard NF EN 116.

[0061] The fuel or combustible composition is as described below and advantageously comprises at least one hydrocarbon cut from one or more sources chosen from the group consisting of mineral sources, preferably petroleum, animal, vegetable and synthetic.

[0062] The crosslinked polymer useful in the invention is used as a TLF booster additive, i.e. in combination with at least one flow improvement additive or cold flow improver (CFI).

[0063] The cold flow additive (CFI) is chosen from copolymers and terpolymers of ethylene and vinyl and / or acrylic ester(s), alone or as a mixture.

[0064] In this embodiment, the crosslinked polymer useful in the invention is used to amplify the fluidizing effect of the cold fluidizing additive, by lowering the filterability limit temperature (FLT).

[0065] This effect is usually referred to as the "TLF booster" effect since the presence of the crosslinked polymer improves the fluidizing character of the CFI additive. This improvement is reflected, in particular, by a significant reduction in the TLF of the fuel composition or combustible additive with this combination compared to the same fuel composition or combustible additive only with the CFI additive, at the same treatment rate. Generally, a significant reduction in the TLF results in a decrease of at least 3°C ​​in the TLF according to standard NF EN 116.

[0066] According to the invention, the crosslinked polymer is used to amplify the fluidizing (flow) effect of the cold flow additive (CFI) by improving the Filterability Limit Temperature (FLT) of the fuel, the FLT being measured according to standard NF EN 116.

[0067] The crosslinked polymer can be added to fuels or combustibles within the refinery, and / or be incorporated downstream of the refinery, possibly in a mixture with other additives, in the form of an additive concentrate, also called according to usage "additive package".

[0068] The crosslinked polymer is advantageously used in the fuel or combustible at a content of at least 2 ppm by weight, preferably at least 3 ppm by weight, and better still at least 5 ppm by weight, more preferably at a content ranging from 2 to 100 ppm by weight, even more preferably from 3 to 50 ppm by weight and better still from 3 to 10 ppm by weight, relative to the total weight of the fuel or combustible composition. The units mentioned in ppm in the present application correspond to ppm by weight unless otherwise indicated. The composition of additives:

[0069] The invention also relates to an additive composition comprising a crosslinked polymer as described above, and one or more cold-thinning additive(s).

[0070] The cold flow additive (CFI) is chosen from copolymers and terpolymers of ethylene and vinyl and / or acrylic ester(s), alone or as a mixture. By way of example, mention may be made of copolymers of ethylene and unsaturated ester, such as ethylene / vinyl acetate (EVA), ethylene / vinyl propionate (EVP), ethylene / vinyl ethanoate (EVE), ethylene / methyl methacrylate (EMMA), and ethylene / alkyl fumarate copolymers described, for example, in documents US3048479, US3627838, US3790359, US3961961 and EP261957.

[0071] According to a preferred embodiment, the cold flow additive (CFI) is chosen from copolymers of ethylene and vinyl ester(s), alone or as a mixture, in particular ethylene / vinyl acetate (EVA) and ethylene / vinyl propionate (EVP) copolymers, more preferably ethylene / vinyl acetate (EVA) copolymers.

[0072] The additive composition may also include one or more other additives commonly used in fuels, other than the crosslinked polymer and cold flow additives described above.

[0073] The additive composition may typically comprise one or more other additives selected from detergents, anti-corrosion agents, dispersants, demulsifiers, anti-foam agents, biocides, reodorants, procetane additives, friction modifiers, lubricity additives or smoothness additives, combustion aids (catalytic combustion and soot promoters), anti-settling agents, anti-wear agents and / or conductivity modifying agents.

[0074] Among these additives, we can cite in particular: a) procetane additives, in particular (but not limited to) chosen from alkyl nitrates, preferably 2-ethylhexyl nitrate, aryl peroxides, preferably benzyl peroxide, and alkyl peroxides, preferably tert-butyl peroxide; b) anti-foam additives, in particular (but not limited to) chosen from polysiloxanes, oxyalkylated polysiloxanes, and fatty acid amides derived from vegetable or animal oils. Examples of such additives are given in EP861882, EP663000, EP736590; (c) detergent and / or anti-corrosion additives, in particular (but not limited to) chosen from the group consisting of amines, succinimides, alkenylsuccinimides, polyalkylamines, polyalkyl polyamines, polyetheramines, quaternary ammonium salts and triazole derivatives; examples of such additives are given in the following documents: EP0938535, US2012 / 0010112 and WO2012 / 004300.(d) lubrication additives or anti-wear agents, in particular (but not limited to) chosen from the group consisting of fatty acids and their ester or amide derivatives, in particular glycerol monooleate, and mono- and polycyclic carboxylic acid derivatives. Examples of such additives are given in the following documents: EP680506, EP860494, WO98 / 04656, EP915944, FR2772783, FR2772784. (e) anti-sedimentation additives and / or paraffin dispersants, in particular (but not limited to) chosen from the group consisting of (meth)acrylic acid / alkyl (meth)acrylate copolymers amidated with a polyamine, polyamine alkenyl succinimides, phthalamic acid and double-chain fatty amine derivatives; alkylphenol resins. Examples of such additives are given in the following documents: EP261959, EP593331, EP674689, EP327423, EP512889, EP832172; US2005 / 0223631; US5998530; WO93 / 14178. .

[0075] The additive composition may advantageously comprise from 0.3 to 30% by weight of crosslinked polymer as described above, relative to the total weight of the additive composition.

[0076] The present invention also relates to an additive concentrate comprising an additive composition as described above, mixed with an organic liquid. The organic liquid is advantageously inert with respect to the constituents of the additive composition, and miscible with fuels or combustibles, in particular those derived from one or more sources chosen from the group consisting of mineral sources, preferably petroleum, animal, vegetable and synthetic.

[0077] The organic liquid is preferably chosen from aromatic hydrocarbon solvents such as the solvent sold under the name “SOLVESSO”, alcohols, ethers and other oxygenated compounds, and paraffinic solvents such as hexane, pentane or isoparaffins, alone or as a mixture. The composition of fuel or combustible:

[0078] The invention also relates to a fuel or combustible composition, comprising: (1) at least one hydrocarbon fraction from one or more sources chosen from the group consisting of mineral, animal, vegetable and synthetic sources, (2) at least one crosslinked polymer as defined above, and (3) at least one cold-thinning additive chosen from copolymers and terpolymers of ethylene and vinyl and / or acrylic ester(s).

[0079] Mineral sources are preferably petroleum.

[0080] The fuel composition according to the invention advantageously comprises the crosslinked polymer(s) in a content of at least 2 ppm by weight, preferably at least 3 ppm, and better still at least 5 ppm, more preferably at a content ranging from 2 to 100 ppm, even more preferably from 3 to 50 ppm, and better still from 3 to 10 ppm by weight.

[0081] According to a preferred embodiment, the cold-fluidifying additive(s) is (are) chosen from ethylene / vinyl acetate (EVA), ethylene / vinyl propionate (EVP), ethylene / vinyl ethanoate (EVE), ethylene / methyl methacrylate (EMMA) copolymers; and more preferably from ethylene / vinyl acetate (EVA) and ethylene / vinyl propionate (EVP) copolymers; even more preferably from ethylene / vinyl acetate (EVA) copolymers.

[0082] The composition advantageously contains at least 20 ppm by weight, preferably at least 50 ppm, advantageously between 20 and 5000 ppm, more preferably between 50 and 1000 ppm by weight of cold-thinning additive(s).

[0083] The fuels or combustibles may be chosen from liquid hydrocarbon fuels or combustibles alone or in a mixture. The liquid hydrocarbon fuels or combustibles include in particular middle distillates with a boiling point between 100 and 500°C.These distillates may, for example, be chosen from distillates obtained by direct distillation of crude hydrocarbons, vacuum distillates, hydrotreated distillates, distillates resulting from catalytic cracking and / or hydrocracking of vacuum distillates, distillates resulting from ARDS (atmospheric residue desulfurization) and / or visbreaking conversion processes, distillates resulting from the recovery of Fischer Tropsch cuts, distillates resulting from BTL (biomass to liquid) conversion of plant and / or animal biomass, taken alone or in combination, and / or biodiesels of animal and / or plant origin and / or oils and / or esters of plant and / or animal oils.

[0084] The sulfur content of the fuels or combustibles is preferably less than 5000 ppm by weight, preferably less than 500 ppm, and more preferably less than 50 ppm, or even less than 10 ppm and advantageously sulfur-free.

[0085] The fuel or combustible is preferably chosen from diesels, biodiesels, type B x diesels and fuel oils, preferably domestic fuel oils (DFO).

[0086] Type B x diesel for diesel engines (compression engines) is a diesel fuel that contains x% (v / v) of vegetable or animal oil esters (including used cooking oils) transformed by a chemical process called transesterification, which reacts this oil with an alcohol to obtain fatty acid esters (FAE). With methanol and ethanol, fatty acid methyl esters (FAME) and fatty acid ethyl esters (FAE) are obtained respectively. The letter "B" followed by a number x ranging from 0 to 100 indicates the percentage of FAE contained in the diesel. Thus, a B99 contains 99% FAE and 1% middle distillates of fossil origin, B20, 20% FAE and 80% middle distillates of fossil origin, etc.We therefore distinguish between type B 0 diesel fuels, which do not contain oxygenated compounds, and type Bx diesel fuels, which contain x% (v / v) of vegetable oil or fatty acid esters, most often methyl esters (EMHV or EMAG). When EAG is used alone in engines, the fuel is referred to as B100.

[0087] The fuel or combustible may also contain hydrogenated vegetable oils, known to those skilled in the art as HVO (from the English “hydrogenated vegetable oil”) or HDRD (from the English “hydrogenation-derived renewable diesel”).

[0088] According to a particular development, the fuel or combustible is chosen from diesels, biodiesels and B x type diesels, hydrogenated vegetable oils (HVO), and their mixtures.

[0089] The fuel composition or combustible may also contain one or more additional additives, other than the crosslinked polymers and cold-thinning additives described above. Such additives may be chosen from detergents, anti-corrosion agents, dispersants, demulsifiers, anti-foaming agents, biocides, reodorants, procetane additives, friction modifiers, lubricity additives or smoothness additives, combustion aid agents (catalytic combustion and soot promoters), anti-sedimentation agents, anti-wear agents and / or conductivity modifying agents.

[0090] These additional additives may generally be present in amounts ranging from 50 to 1,000 ppm by weight (each).

[0091] According to another embodiment of the invention, a method for lowering the filterability limit temperature of a fuel or combustible composition comprises a step of treating said composition with at least one crosslinked polymer as described above, and with one or more cold-thinning additive(s) chosen from copolymers and terpolymers of ethylene and vinyl and / or acrylic ester(s).

[0092] According to a preferred embodiment, such a method comprises the successive steps of: a) determining an additive composition(s) most suitable for the fuel composition to be treated as well as the treatment rate necessary to achieve a maximum filterability limit temperature value for the specific fuel composition, said additive composition(s) comprising at least one crosslinked polymer according to the invention and at least one cold flow additive (CFI); b) treating the fuel composition with the quantity determined in step a) of said additive composition(s).

[0093] The method according to the invention is typically intended for a fuel or combustible composition as described above.

[0094] Step (a) is carried out using any known method and is standard practice in the field of fuel additives. This step involves defining a target value and then determining the improvement required to achieve the specification.

[0095] In particular, the specification is a maximum TLF according to standard NF EN 116. The determination of the quantity of additive composition(s) to be added to the fuel or combustible composition to achieve the specification will typically be carried out by comparison with the fuel or combustible composition without said additive composition(s).

[0096] The amount of crosslinked polymer required to treat the fuel composition may vary depending on the nature and origin of the fuel, in particular the level and nature of the paraffinic compounds it contains. The nature and origin of the fuel may therefore also be a factor to be taken into account for step a).

[0097] The above method may also comprise an additional step after step b) of verifying the target achieved and / or adjusting the treatment rate with the additive composition(s).

[0098] The following examples are given as illustrations of the invention, and should not be interpreted in such a way as to limit its scope. EXAMPLES Example 1: Synthesis of crosslinked and non-crosslinked polymers containing units of formula (I) C12 / C14 alkyl methacrylate homopolymer non-crosslinked (comparative):

[0099] 7.0 g (0.0262 mol) of C 12 / C 14 alkyl methacrylate monomer are introduced into a 50 mL single-necked flask, then 0.299 g (0.00135 mol) of RAFT agent (2-cyano-2-propyl benzodithioate) and 4.12 g (4.0 mL) of 1,4-dioxane are added. The monomer concentration is set at 2.0 mol L -1< . The flask is then degassed for 30 minutes under nitrogen and with magnetic stirring, then sealed. In parallel, 0.0286g (1.74.10 -4< mol) of AIBN (azobis isobutyronotrile) are introduced into a second 25mL flask, as well as 1.03g (1.0mL) of 1,4-dioxane as dissolution solvent. The second flask is in turn degassed for 30 minutes under nitrogen. The AIBN solution is then transferred using a nitrogen-purged syringe into the 50mL flask, previously heated to 80°C, to start the polymerization. The reaction is left for 24h. Once the polymerization is complete, the solvent is evaporated under reduced pressure (55mbar) at 60°C to recover the polymer. C12 / C14 alkyl methacrylate homopolymer crosslinked (in accordance with the invention):

[0100] 7.0 g (0.0262 mol) of C 12 / C 14 alkyl methacrylate monomer are introduced into a 50 mL single-necked flask, then 0.285 g (0.00129 mol) of RAFT agent (2-cyano-2-propyl benzodithioate), 0.340 g (0.00131 mol) of crosslinking agent 1,6-hexanediol dimethacrylate and 16.3 g (15.8 mL) of 1,4-Dioxane are added. The monomer concentration is set at 1.0 mol L -1< . The flask is then degassed for 30 minutes under nitrogen and with magnetic stirring, then sealed. In parallel, 0.0270g (1.61.10 -4< mol) of AIBN are introduced into a second 25mL flask, as well as 2.0g (1.94mL) of 1,4-dioxane as a dissolution solvent. The second flask is in turn degassed for 30 minutes under nitrogen. The AIBN solution is then transferred using a nitrogen-purged syringe into the 50mL flask, previously heated to 80°C, to start the polymerization. The reaction is left for 24h.Once the polymerization is complete, the solvent is evaporated under reduced pressure (55mbar) at 60°C to recover the crosslinked polymer. C12 / C14 alkyl acrylate copolymer - crosslinked 1-vinylimidazole (in accordance with the invention):

[0101] 10.9 g (0.044 mol) of C 12 / C 14 alkyl acrylate monomer and 1.03 g (0.0109 mol) of a second N-vinylimidazole monomer are introduced into a 50 mL single-necked flask, then 0.548 g (0.00263 mol) of RAFT agent (2-cyano-2-propyl dodecyl trithiocarbonate), 0.589 g (0.00275 mol) of crosslinking agent and 19.8 g (19.2 mL) of 1,4-dioxane are added. The total concentration of two monomers is set at 1.5 mol L -1 < . The flask is then degassed for 30 minutes under nitrogen and with magnetic stirring, then sealed. In parallel, 0.051g (3.1.10 -4< mol) of AIBN are introduced into a second 25mL flask, as well as 2.0g (1.94mL) of 1,4-dioxane as a dissolution solvent. The second flask is in turn degassed for 30 minutes under nitrogen. The AIBN solution is then transferred using a nitrogen-purged syringe into the 50mL flask, previously heated to 80°C, to start the polymerization. The reaction is left for 24h.Once the polymerization is complete, the solvent is evaporated under reduced pressure (55mbar) at 60°C to recover the crosslinked copolymer.

[0102] An uncrosslinked C12 / C14 alkyl acrylate homopolymer (comparative), as well as additional crosslinked C12 / C14 alkyl acrylate homopolymers (in accordance with the invention) and additional crosslinked C12 / C14 alkyl acrylate - 1-vinylimidazole copolymers (in accordance with the invention) were synthesized, following synthesis protocols analogous to those described above.

[0103] The characteristics of all the synthesized polymers are gathered in the table below: Polymer Crosslinking agent + crosslinking rate MW (g. mol -1< ) M n (g.mol -1< ) Ð (dispersity) C12 / C14 alkyl methacrylate homopolymer NO crosslinking agent 9600 8000 1,2 C12 / C14 alkyl methacrylate homopolymer 1,6 hexanediol dimethacrylate, 5% 34100 15300 2,23 C12 / C14 alkyl acrylate homopolymer NO crosslinking agent 8000 7000 1,14 C12 / C14 alkyl acrylate homopolymer 1,6 hexanediol diacrylate, 5% 16800 10600 1,58 C12 / C14 alkyl acrylate homopolymer di(ethylene glycol) diacrylate, 5% 13000 9400 1,38 C12 / C14 alkyl acrylate homopolymer 1,6 hexanediol ethoxylate diacrylate, 5% 28300 12600 2,24 C12 / C14 alkyl acrylate copolymer (80 mol%) - 1 vinylimidazole (20 mol%) 1,6 hexanediol diacrylate, 5% 11900 7500 1,59 C12 / C14 alkyl acrylate copolymer (85% mol) - 1 vinylimidazole (15% mol) di(ethylene glycol) diacrylate, 5% 11000 7200 1,53 C12 / C14 alkyl acrylate copolymer (80 mol%) - 1 vinylimidazole (20 mol%) 1,6 hexanediol ethoxylate diacrylate, 5% 11800 7100 1,66 Example 2 : Evaluation of cold holding performance

[0104] The polymers described in Example 1 were tested as cold resistance additives in a particularly difficult-to-process diesel fuel composition G, the characteristics of which are detailed in the table below: Characteristic Method Value Density at 15°C ISO 12185 831.2 kg / m 3< Viscosity at 20°C ISO 3104 5.1 mm 2 < / s Viscosity at 40°C ISO 3104 3.5 mm 2 < / s Cloud Point (CTP)° EN 23015 -3°C Filterability Limit Temperature (FLT) EN 116 -2°C Pour point (PTE) ASTM D 7346 -12°C Paraffin content 21.42% by weight C16+ n-paraffin content 11.30% by weight Distillation profile D86 ISO 3405 Initial point 173,0°C Point at 5% vol. 196,6°C Point at 10% vol. 215,4°C Point at 20% vol. 243,4°C Point at 30% vol. 261,9°C Point at 40% vol. 276,0°C Point at 50% vol. 287,7°C Point at 60% vol. 299,3°C Point at 70% vol. 311,4°C Point at 80% vol. 325,5°C Point at 90% vol. 343,7°C Point at 95% vol. 356,2°C Full stop 359,0°C Distilled volume 97,4 ml Residue 0,6 ml Losses 1,8 ml

[0105] Diesel composition G was added with a package containing the following two classic commercial cold flow additives (CFI additives), in Solvesso 150 solvent: 0.5% by weight of CP7956C additive marketed by the company Total Additifs Carburants Spéciaux, which is an ethylene-vinyl acetate (EVA) copolymer; 0.5% by weight of Dodiflow D4134 additive marketed by the company Clariant, which is an ethylene-vinyl acetate-vinyl neodecanoate terpolymer.

[0106] This package was incorporated into the diesel composition G at a content of 300 ppm by weight of active material (i.e. 150 ppm by weight of each additive) relative to the total weight of the diesel composition.

[0107] This resulted in the composition of additive diesel G1.

[0108] The performance as cold-holding additives of each of the polymers of Example 1 was tested, by evaluating their ability to lower the filterability limit temperature (TFL) of the additive diesel composition G1.

[0109] Each polymer was added at a content of 3 ppm by weight to composition G1, to give diesel G2, the TLF of which was then measured, in accordance with standard EN 116.

[0110] The results obtained are shown in the table below: Polymer Crosslinking agent TLF (°C) diesel G2 Difference of TLF: TLF G1-TLF G2 C12 / C14 alkyl methacrylate homopolymer NO crosslinking agent -12 1 C12 / C14 alkyl methacrylate homopolymer 1,6 hexanediol dimethacrylate -16 5 C12 / C14 alkyl acrylate homopolymer NO crosslinking agent -11 0 C12 / C14 alkyl acrylate homopolymer 1,6 hexanediol diacrylate -14 3 C12 / C14 alkyl acrylate homopolymer di(ethylene glycol) diacrylate -14 3 C12 / C14 alkyl acrylate homopolymer 1,6 hexanediol ethoxylate diacrylate -15 4 C12 / C14-1 alkyl acrylate vinylimidazole copolymer 1,6 hexanediol diacrylate -16 5 C12 / C14-1 alkyl acrylate vinylimidazole copolymer di(ethylene glycol) diacrylate -16 5 C12 / C14-1 alkyl acrylate vinylimidazole copolymer 1,6 hexanediol ethoxylate diacrylate -15 4

[0111] The above results show that the use of crosslinked polymers according to the invention leads to a significant reduction in the TLF, ranging from 3 to 5 points. Surprisingly, crosslinked polymers give better results than non-crosslinked polymers.

Claims

1. Use, for lowering the cold filter plugging point, measured according to standard NF EN 116, of a fuel composition, of one or more crosslinked polymers comprising at least one unit of the following formula (I): wherein R1 represents a hydrogen atom or a methyl group, E is a group -CO-O- linked to the vinyl carbon via the carbon atom , G is a linear or branched acyclic C6 to C24 alkyl group, said copolymer having a degree of crosslinking, corresponding to the amount in moles of crosslinking agent relative to the total amount in moles of monomers in the polymer, excluding the crosslinking agent, in the range from 0.5% to 30%, the crosslinking agent of the polymer being selected from diacrylates and dimethacrylates of following formula (III): with - R representing a hydrocarbon chain comprising from 2 to 16 carbon atoms, which may be interrupted by one or more heteroatoms selected from N and O, and which may be substituted by one or more - OZ groups with Z representing a hydrogen atom or a C1 to C4 alkyl radical, and - R2 and R3 independently representing a hydrogen atom or a methyl group, characterized in that said polymer is used in combination with at least one cold flow improver selected from copolymers and terpolymers of ethylene and vinyl and / or acrylic ester(s), alone or as a mixture.

2. The use as claimed in any one of the preceding claims, characterized in that the group G of formula (I) is a linear or branched C8 to C22 acyclic alkyl radical, even better C12 to C14 or C18 to C22, and even more preferentially C12 to C14.

3. The use as claimed in any one of the preceding claims, characterized in that the crosslinked polymer is a homopolymer.

4. The use as claimed in any one of claims 1 or 2, characterized in that the crosslinked polymer is a copolymer selected from block copolymers and statistical copolymers, preferably from statistical copolymers.

5. The use as claimed in the preceding claim, characterized in that the polymer comprises units derived from one or more vinyl monomers selected from: - 2-phenoxyethylacrylate: - 1-vinylimidazole: - N-vinylpyrrolidone:

6. The use as claimed in any one of the preceding claims, characterized in that the polymer has a degree of crosslinking in the range from 1% to 20%, more preferentially from 2% to 10%, and even better from 3% to 6%.

7. The use as claimed in any one of the preceding claims, characterized in that the crosslinking agent is selected from - 1,6-hexanediol dimethacrylate; - di(ethylene glycol) dimethacrylate; - glycerol dimethacrylate; - 1,6-hexanediol diacrylate; - di(ethylene glycol) diacrylate; and - 1,6-hexanediol ethoxylate diacrylate.

8. The use as claimed in any one of the preceding claims, characterized in that the fuel composition is selected from diesels, biodiesel, Bx type diesels and fuel oils such as domestic heating oils (DHO).

9. The use as claimed in any one of the preceding claims, characterized in that said crosslinked polymer is used in combination with at least one cold flow improver selected from ethylene / vinyl acetate (EVA), ethylene / vinyl propionate (EVP), ethylene / vinyl ethanoate (EVE) and ethylene / methyl methacrylate (EMMA) copolymers; and more preferentially among ethylene / vinyl acetate (EVA) and ethylene / vinyl propionate (EVP) copolymers; still more preferentially among ethylene / vinyl acetate (EVA) copolymers.

10. The use as claimed in any one of the preceding claims, characterized in that said crosslinked polymer is used in a content ranging from 2 to 100 ppm by weight, even more preferentially from 3 to 50 ppm by weight, and even better from 3 to 10 ppm by weight, based on the total weight of the fuel composition.

11. An additive composition comprising a crosslinked polymer as defined in any one of claims 1 to 7 and one or more cold flow improver(s) selected from copolymers and terpolymers of ethylene and vinyl and / or acrylic ester(s); preferably among ethylene / vinyl acetate (EVA), ethylene / vinyl propionate (EVP), ethylene / vinyl ethanoate (EVE), ethylene / methyl methacrylate (EMMA) copolymers; and more preferentially among ethylene / vinyl acetate (EVA) and ethylene / vinyl propionate (EVP) copolymers; and more preferentially still among ethylene / vinyl acetate (EVA) copolymers.

12. A fuel composition comprising: (1) at least one hydrocarbon fraction from one or more sources selected from the group consisting of mineral, animal, vegetable and synthetic sources, (2) at least one crosslinked polymer as defined in any one of claims 1 to 7, and (3) at least one cold flow improver selected from copolymers and terpolymers of ethylene and vinyl and / or acrylic ester(s).

13. The composition as claimed in the preceding claim, characterized in that it contains the crosslinked polymer(s) in an amount of 2 to 100 ppm by weight, even more preferentially 3 to 50 ppm by weight, and even better 3 to 10 ppm by weight.

14. The composition as claimed in one of claims 12 and 13, characterized in that the cold flow improver(s) is (are) selected from ethylene / vinyl acetate (EVA), ethylene / vinyl propionate (EVP), ethylene / vinyl ethanoate (EVE), ethylene / methyl methacrylate (EMMA) copolymers; and more preferentially among ethylene / vinyl acetate (EVA) and ethylene / vinyl propionate (EVP) copolymers; even more preferentially among ethylene / vinyl acetate (EVA) copolymers.

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