EP1881055B1 - Additives to improve the cold properties of fuel oils - Google Patents

Description

The present invention relates to ethylene-propene-vinyl ester terpolymers which have improved handleability and improved performance properties as refrigerants for fuel oils.

Depending on the origin of the crude oils, crude oils and middle distillates obtained by distillation of crude oils, such as gas oil, diesel oil or fuel oil, contain different amounts of n-paraffins, which crystallize out as platelet-shaped crystals when the temperature is lowered and partly agglomerate with the inclusion of oil. As a result of this crystallization and agglomeration, the flow properties of the oils or distillates deteriorate, which can lead to disruptions in the extraction, transport, storage and / or use of the mineral oils and mineral oil distillates. When transporting mineral oils through pipelines, the phenomenon of crystallization, especially in winter, can lead to deposits on the pipe walls and in individual cases, e.g. at standstill of a pipeline, even lead to their complete blockage. During storage and further processing of the mineral oils, it may also be necessary in winter to store the mineral oils in heated tanks to ensure their flowability. With mineral oil distillates, as a result of the crystallization, clogging of the filters in diesel engines and furnaces may occur, as a result of which reliable metering of the fuel is prevented and, under certain circumstances, a complete interruption of the fuel or heating medium supply occurs.

In addition to the classical methods for the removal of crystallized paraffins (thermal, mechanical or with solvents), which relate only to the removal of already formed precipitates, chemical additives (so-called flow improvers) have been developed in recent years. The additives act as additional nuclei and partially crystallize out with the paraffins, creating a larger number of smaller paraffin crystals with changed crystal form arises. The modified paraffin crystals are less prone to agglomeration, so that the oils added with these additives can still be pumped or processed at temperatures which are often more than 20 ° C. lower than for non-additized oils.

Another object of flow improvers is to disperse the wax crystals, i. the delay or prevention of the sedimentation of paraffin crystals and thus the formation of a paraffin-rich layer at the bottom of storage containers.

One known additive class widely used for improving the low temperature properties of mineral oils and middle distillates made therefrom are copolymers of ethylene and vinyl esters, especially ethylene and vinyl acetate ("EVA"). These are partially crystalline polymers whose mode of action is explained by a cocrystallization of their poly (ethylene) sequences with the precipitated on cooling from the middle distillates n-paraffins. Through this physical interaction, the shape, size and adhesion properties of the precipitated wax crystals are modified to produce many small crystals that pass through the fuel filter and can be supplied to the combustion chamber. Due to their crystallinity, these ethylene-vinyl ester copolymers must be handled and metered at elevated temperature or, alternatively, made manageable via a high dilution with solvents.

However, there are also applications such as e.g. Storage tanks in terminals or remote areas where these stored under ambient conditions additives for lack of opportunities for preheating of oil and / or additive must be added directly to the oils to be added and especially cold oils. There is a risk that the additives remain unsolved, so they can not develop their effectiveness and also can give rise to filter occupancy and filter blockages.

It is also known that the self-flowability of ethylene-vinyl ester copolymers and their dispersions by a high proportion of so-called short chain branching, such as, for example, by polymerization at high Temperatures and / or low pressures can be adjusted to improve. These short-chain branches are formed by intramolecular chain transfer reactions ("back-biting mechanism") during radical polymerization and essentially consist of butyl and ethyl radicals (see, for example, US Pat Macromolecules 1997, 30, 246-256 ). However, these short chain branches significantly reduce the effectiveness of these polymers as cold additives.

Structures comparable to short chain branches and related effects are obtained by the incorporation of branched comonomers such as isobutylene ( EP-A-0 099 646 ), 4-methylpentene ( EP-A-0 807 642 ) or diisobutylene ( EP-A-0 203 554 ) in EVA copolymers. While the incorporation of these monomers improves the flowability and solubility of the polymers, it also reduces their effectiveness as a cold additive.

1. A) mindestens ein Copolymer aus Ethylen und 8-21 Mol-% mindestens eines Acryl- oder Vinylesters mit einem C₁-C₁₈-Alkylrest und
2. B) mindestens ein Kammpolymer

, worin in Bestandteil A außer Ethylen 3,5 bis 20 Mol-% Vinylacetat und 0,1 bis 12 Mol-% Neononansäurevinylester, 2-Ethylhexansäurevinylester und/oder Neodecansäurevinylester enthalten sind, wobei der gesamte Comonomergehalt zwischen 8 und 21 Mol-% liegt,
worin in Bestandteil A neben Ethylen und 8 bis 18 Mol-% Vinylestern noch 0,5 bis 10 Mol-% Olefine, ausgewählt aus Propen, Buten, Isobutylen, Hexen, 4-Methylpenten, Octen, Diisobutylen oder Norbornen enthalten sind, und
worin die Copolymere, die Bestandteil A ausmachen, Verzweigungsgrade zwischen 1 und 9 CH₃/100 CH₂-Gruppen, die nicht aus den Comonomeren stammen, aufweisen.A fuel oil composition containing a fuel oil of animal or vegetable origin and an additive containing

1. A) at least one copolymer of ethylene and 8-21 mol% of at least one acrylic or vinyl ester having a C ₁ -C ₁₈ alkyl radical and
2. B) at least one comb polymer

in which component A contains, in addition to ethylene, 3.5 to 20 mol% of vinyl acetate and 0.1 to 12 mol% of vinyl neononanoate, vinyl 2-ethylhexanoate and / or vinyl neodecanoate, the total comonomer content being between 8 and 21 mol%,
wherein in component A in addition to ethylene and 8 to 18 mol% of vinyl esters are still 0.5 to 10 mol% of olefins selected from propene, butene, isobutylene, hexene, 4-methylpentene, octene, diisobutylene or norbornene, and
wherein the copolymers that constitute Component A, degrees of branching 1-9 CH _3/100 CH ₂ groups, which do not stem from the comonomers have.

EP-A-0 190 553 discloses terpolymers of ethylene, 20-40 wt .-% of vinyl acetate and propene having a degree of branching 8-25 CH _3/100 CH ₂ groups. In the Examples polymers having 25.7 to 29.1 wt .-% of vinyl acetate and branching degrees of 14 to 20 CH _3/100 CH are disclosed ₂ groups, whose molecular weight was only set by the moderating effect of propene. Alone, they show little effectiveness as cold flow improvers and are used to improve the solubility of conventional EVA copolymers.

EP-A-0 406 684 discloses polymer blends which may contain ethylene-vinyl acetate co- and terpolymers having a vinyl acetate content of 25-35 weight percent and a degree of branching of 3 to 15 CH ₃ groups. The terpolymers may contain 5 to 15% by weight of olefins such as propene. The examples show an EVA terpolymer with diisobutylene.

DD-A-161 128 discloses a process for producing a high distillate middle distillate flow improver in which ethylene polymerizes with 10-50% by weight of vinyl acetate and 0.1-10% by mole of an N-alkene of 3 to 8 carbon atoms in the presence of hydrogen as a moderator becomes. However, the high polymerization temperature of 265 ° C shown in the examples requires a high proportion of Short chain branches with only a very low content of propene of less than 1 mol%.

Although the self-flowability of the polymers can be improved by short-chain branching as well as by longer-chain and especially branched olefinic comonomers, this is often accompanied by a loss of effectiveness, since the optimum range for the cocrystallization with paraffins range of poly (ethylene) sequence lengths is left or Even small amounts of the comonomers cause so much disruption of the polyethylene sequences that effective cocrystallization with the paraffins of the oil is no longer possible.

The incorporation of larger amounts of the known branched olefins such as isobutylene, 4-methylpentene or diisobutylene in polymers of ethylene and unsaturated esters is also limited by the fact that these olefins have such a strong moderating effect on the polymerization, so that the need for initiators for commercial Applications prohibitive level achieved and / or no commercially interesting turnover in the polymerization can be achieved. In addition, the resulting, strongly short-chain-branched products do not show sufficient effectiveness as flow improvers.

It was therefore an object of the present invention to provide additives which are at temperatures of for example below -10 ° C such as below -15 ° C, especially below -20 ° C and in special cases below -25 ° C in the most concentrated form, that is, in formulations with at least 20 wt .-%, preferably at least 25 wt .-% and especially at least 30 wt .-% such as at least 35 wt .-% polymer in a solvent flowable and easily pumped, at these temperatures residue dissolve in fuel oils and show a comparison with the additives of the prior art equal or improved effectiveness.

It has now been found that concentrates of terpolymers of ethylene, propene and vinyl, acrylic and / or methacrylic acid esters with a certain proportion of comonomers, short-chain branches and propene-derived methyl groups are very easy to handle in the cold at the same time show superior effectiveness as a cold additive. It is of particular importance that the propylene is incorporated as a comonomer in the polymer chain and is bound not only in terms of a moderator to the chain end. In addition, these polymers can be prepared in conventional systems with commercially interesting sales.

1. a) 12,0 bis 16,0 mol-% von mindestens einem ethylenisch ungesättigten Ester abgeleitete Struktureinheiten enthalten,
2. b) 1,0 bis 4,0 vom Propen abgeleitete Methylgruppen pro 100 aliphatische C-Atome enthalten, und
3. c) weniger als 6,5 von Kettenenden stammende Methylgruppen pro 100 CH₂-Gruppen aufweisen.

The invention thus relates to terpolymers of ethylene, at least one ethylenically unsaturated ester and propene, which

1. a) contain from 12.0 to 16.0 mol% of structural units derived from at least one ethylenically unsaturated ester,
2. b) contain 1.0 to 4.0 propene-derived methyl groups per 100 aliphatic C atoms, and
3. c) have less than 6.5 chain ends methyl groups per 100 CH ₂ groups.

Another object of the invention are flowable additive concentrates with an own-floor point of -15 ° C and below, containing at least 20 wt .-% of at least one as defined above terpolymer of ethylene, at least one unsaturated ester and propene, in organic solvent.

A further subject matter is the use of a terpolymer of ethylene, at least one unsaturated ester and propene as defined above for improving the cold flowability of middle distillates.

Another object of the invention is a method for improving the cold flowability of middle distillates by the middle distillate at temperatures below 0 ° C an additive concentrate containing at least 20 wt .-% of at least one as defined above terpolymer of ethylene, at least one unsaturated ester and propene a temperature of 0 ° C or below, is added.

Particularly suitable unsaturated esters according to the invention are vinyl esters of carboxylic acids having 2 to 12 carbon atoms and esters of acrylic and methacrylic acid with fatty alcohols having 1 to 12 carbon atoms.

Particularly preferred ethylenically unsaturated esters are vinyl esters of carboxylic acids having 2 to 12 carbon atoms. These are preferably those of the formula 1

CH ₂ = CH-OCOR ¹ (1)

wherein R ^{1 is} C ₁ to C ₁₁ alkyl, preferably C ₁ to C ₈ alkyl and especially C ₁ - to C ₄ alkyl. The alkyl radicals can be linear or branched. Preferred branched alkyl radicals carry a branch in the 1- or 2-position to the carbonyl group. Examples of suitable vinyl esters are vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pentanoate, vinyl pivalate, vinyl n-hexanoate, vinyl 2-ethylhexanoate, vinyl neononanoate, vinyl neo-decanoate and vinyl neo-decanoate. Particularly preferred are vinyl esters of short-chain fatty acids having 1 to 4 carbon atoms. Especially preferred is vinyl acetate.

Also preferred as ethylenically unsaturated esters are esters of acrylic and methacrylic acid with fatty alcohols having 1 to 12 carbon atoms. These are preferably those of the formula 2

CH ₂ = CR ² -COOR ³ (2)

wherein R ^{2 is} hydrogen or methyl and R ^{3 is} C ₁ - to C ₁₂ -alkyl, preferably C ₁ - to C ₈ -alkyl, especially C ₁ - to C ₆ -alkyl, such as, for example, C ₁ - to C ₄ -alkyl. Suitable acrylic esters include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n- and iso-butyl (meth) acrylate, hexyl, octyl, 2-ethylhexyl (meth) acrylate and mixtures thereof comonomers. Methyl acrylate and ethyl acrylate are particularly preferred.

The content of the terpolymers of unsaturated ester is preferably between 12.0 and 15.5 mol%, for example between 12.5 and 15.0 mol%. In the case of vinyl acetate, which is particularly preferred as the ethylenically unsaturated ester, the content is preferably between 28.0 and 36.0 wt .-%, in particular between 29.5 and 35.0 wt .-%, such as between 31.0 and 34.0 wt .-%. The determination of the vinyl ester content is carried out by pyrolysis of the polymer and subsequent titration of the eliminated carboxylic acid.

The content of the polymer in methyl groups derived from the propene is preferably between 1.5 and 3.8 and in particular between 1.8 and 3.5 methyl groups per 100 aliphatic carbon atoms.

The content of propene-derived methyl groups in the polymers of the invention (propene-CH ₃ ) is determined by means of ¹³ C-NMR spectroscopy. Thus, terpolymers of ethylene, vinyl ester and propene show characteristic signals of methyl groups attached to the polymer backbone of between about 19.3 and 20.2 ppm, which have a positive sign in the DEPT experiment. The integral of this signal of the propene-derived methyl side groups of the polymer backbone is related to that of all other aliphatic C atoms of the polymer backbone between about 22.0 and 44 ppm. Optionally derived from the alkyl radicals of the unsaturated ester and superimposed with the signals of the polymer backbone signals are subtracted based on the signal of the carbonyl group of the unsaturated ester adjacent methine group of the total integral of the aliphatic C-atoms. Such measurements can be performed, for example, with NMR spectrometers at a measurement frequency of 125 MHz at 30 ° C in solvents such as CDCl ₃ or C ₂ D ₂ Cl ₄ .

The number of chain ends originating from the methyl groups in the polymer is preferably from 2.0 to 6.0 CH _3/100 CH ₂ groups and in particular from 3.0 to 5.5 CH _3/100 CH ₂ groups.

The number of methyl groups derived from chain ends is understood to mean all those methyl groups of the polymer which do not originate from the unsaturated esters used as comonomers. This is understood to mean both the methyl groups located at the main chain ends, including the methyl groups derived from structural units of the moderator, and the methyl groups derived from short chain branches.

The number of methyl groups derived from chain ends is determined by means of ¹ H-NMR spectroscopy, in which the integral of the signals usually appearing in the ¹ H-NMR spectrum with a chemical shift of between about 0.7 and 0.9 ppm (versus TMS) Methyl protons is compared with the integral of appearing at 0.9 to 1.9 ppm signals of the methylene protons. The methyl and methylene groups derived from alkyl radicals of the comonomers, for example the acetyl group of the vinyl acetate, are not included or excluded. The signals generated by the structural units of the moderator are assigned according to the methyl or methylene protons. From the resulting value, the number of propene-derived methyl groups, as determined by ¹³ C-NMR spectroscopy, is subtracted to obtain the number of methyl groups derived from chain ends. Suitable ¹ H NMR spectra, for example, at a measurement frequency of 500 MHz at 30 ° C in solvents such as CDCl ₃ or C ₂ D ₂ Cl _{4 are} recorded.

zwischen 14,5 und 18,0, bevorzugt zwischen 15,0 und 17,8 wie beispielsweise zwischen 15,5 und 17,5. Die beiden Summanden sind als dimensionslose Zahlen zu addieren.The sum G of molar content of unsaturated ester a) and the number of propylene-derived methyl groups per 100 aliphatic C atoms of the polymer is preferably b) $$\mathrm{G}=\left[\mathrm{mol}-\%\mathrm{unsaturated\; ester}\right]+\left[\mathrm{propene}-{\mathrm{CH}}_3\right]$$

between 14.5 and 18.0, preferably between 15.0 and 17.8 such as between 15.5 and 17.5. The two summands are to be added as dimensionless numbers.

The weight-average molecular weight M w of the terpolymers of the invention determined by gel permeation chromatography against poly (styrene) standards is preferably between 1,000 and 25,000 g / mol, preferably between 2,000 and 20,000 g / mol, for example between 2,500 and 15,000 g / mol. The polydispersity of the polymers is preferably less than 8, for example 2 to 6. The melt viscosity, determined at 140 ° C., of the polymers according to the invention is between 50 and 5,000 mPas, preferably between 80 and 2,500 mPas and in particular between 100 and 1,000 mPas.

For all analyzes, the polymer to be examined is previously freed for two hours at 140 ° C. in vacuo (100 mbar) of residual monomers and any solvent fractions.

The copolymers according to the invention can be prepared by suspension polymerization, solvent polymerization, gas-phase polymerization or high-pressure bulk polymerization. The high-pressure mass polymerization is preferably carried out at pressures above 100 MPa, preferably between 100 and 300 MPa, for example between 150 to 275 MPa and temperatures of 100 to 260 ° C, preferably 150 to 240 ° C, for example between 180 and 220 ° C. By suitable choice of the reaction conditions and the amounts of monomers used, the propene content as well as the extent of short chain branching can be adjusted. In particular, low reaction temperatures and / or high pressures lead to low fractions of short chain branches and thus to a low number of chain ends.

The reaction of the monomers is initiated by free radical initiators (free radical initiators). This class of substance includes e.g. Oxygen, hydroperoxides, peroxides and azo compounds such as cumene hydroperoxide, t-butyl hydroperoxide, dilauroyl peroxide, dibenzoyl peroxide, bis (2-ethylhexyl) peroxide carbonate, t-butyl perpivalate, t-butyl permalate, t-butyl perbenzoate, dicumyl peroxide, t-butylcumyl peroxide, di- (t-butyl ) peroxide, 2,2'-azobis (2-methylpropanonitrile), 2,2'-azobis (2-methylbutyronitrile). The initiators are used individually or as a mixture of two or more substances in amounts of 0.01 to 10 wt .-%, preferably 0.05 to 5 wt .-%, based on the monomer mixture.

The high-pressure mass polymerization is carried out batchwise or continuously in known high-pressure reactors, for example autoclaves or tubular reactors, and continuously operated tubular reactors have proven particularly suitable. Solvents such as aliphatic and / or aromatic hydrocarbons or hydrocarbon mixtures, benzene or toluene may be present in the reaction mixture. Preferred is the substantially solvent-free operation. In a preferred embodiment of the polymerization, the mixture of the monomers, the initiator and, if used, the moderator, a tubular reactor supplied via the reactor inlet and one or more branches. The comonomers as well as the moderators can be metered into the reactor both together with ethylene and separately via side streams. In this case, the monomer streams can be composed differently ( EP-A-0 271 738 and EP-A-0 922 716 ).

It has proved to be advantageous not only to adjust the molecular weight of the polymers via the moderating effect of the propene but additionally to use such moderators which essentially only effect chain transfer and are not incorporated in the form of comonomers into the polymer chains. Thus, by use of propene, methyl groups can be selectively incorporated as impurities in the polymer backbone, and polymers with improved effectiveness as cold flow improvers are obtained. Preferred moderators are, for example, saturated and unsaturated hydrocarbons such as propane, hexane, heptane and cyclohexane and alcohols such as butanol and in particular aldehydes such as acetaldehyde, propionaldehyde, n-butyraldehyde and isobutyraldehyde and ketones such as acetone, methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, Methyl butyl ketone, methyl isobutyl ketone and cyclohexanone. Hydrogen is also suitable as a moderator.

In a particularly preferred embodiment, the polymers according to the invention contain, in addition to vinyl esters and propene, from 0.5 to 7.0% by weight, preferably from 1.0 to 5.0% by weight, of structural units derived from at least one carbonyl-containing moderator , The concentration of these structural elements derived from the moderator in the polymer can also be determined by means of ¹ H-NMR spectroscopy. This can be done, for example, by correlating the intensity of the vinyl ester-derived signals, the proportion of which in the polymer is known, with the signals appearing at about 2.4 to 2.5 ppm of the methylene or methine group adjacent to the carbonyl group of the moderators.

The polymers according to the invention are usually used as concentrates in organic solvents for better handling. suitable Solvents or dispersants are, for example, higher-boiling aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, esters, ethers and mixtures thereof. The additives according to the invention preferably contain from 10 to 90% by weight, in particular from 20 to 80% by weight and especially from 50 to 75% by weight, for example from 60 to 70% by weight, of solvent.

Surprisingly, it has been found that the self-stick point of the terpolymers of the invention when diluted to an active ingredient content of less than 40 wt .-%, preferably 20 to 40 wt .-%, in particular 25 to 40 wt .-%, such as 30 to 35 parts by weight. % Active ingredient drops significantly more than in polymers of the prior art. This effect is particularly pronounced in predominantly aromatic solvents and solvent mixtures. Thus, concentrates are obtained with eigenstock points of -30 ° C and below. At the same time, the effectiveness of the polymers according to the invention is superior to those of the prior art at the same additive concentration in the additized oil. Surprisingly, such concentrates of the terpolymers of the invention can also be mixed into fuel oils having temperatures below 0 ° C., for example below -10 ° C. and partially below -25 ° C., without resulting in a deterioration in the filterability of the additive-fuel oils known from conventional additives comes through undissolved portions of the additive. Thus, it is possible with the additives according to the invention to improve the cold flow properties of fuel oils without prior heating of oil and / or additive.

The polymers according to the invention are used alone or in a mixture with other constituents as additives for mineral oil distillates, in the following they are therefore also referred to as additives according to the invention.

The additives according to the invention can also be added to middle distillates for improving cold flowability in combination with further additives such as, for example, further ethylene copolymers, polar nitrogen compounds, alkylphenol-aldehyde resins, comb polymers, polyoxyalkylene compounds and / or olefin copolymers.

If the additives according to the invention are used for middle distillates, they also contain, in a preferred embodiment, one or more of the constituents II to VII in addition to the terpolymers according to the invention.

Thus, they preferably contain one or more further copolymers of ethylene and olefinically unsaturated compounds, in particular unsaturated esters, as constituent II. Particularly suitable ethylene copolymers are those which in addition to ethylene have 6 to 21 mol%, in particular 10 to 18 mol% Comonomers included.

The olefinically unsaturated compounds are preferably vinyl esters, acrylic esters, methacrylic esters, alkyl vinyl ethers and / or alkenes, it being possible for the abovementioned compounds to be substituted by hydroxyl groups. One or more comonomers may be included in the polymer.

The vinyl esters are preferably those of the formula 3

CH ₂ = CH-OCOR ¹¹ (3)

wherein R ^{11 is} C ₁ to C ₃₀ alkyl, preferably C ₄ to C ₁₆ alkyl, especially C ₆ to C ₁₂ alkyl. In a further embodiment, said alkyl groups may be substituted with one or more hydroxyl groups.

In a further preferred embodiment, R ^{11 is} a branched alkyl radical or a neoalkyl radical having 7 to 11 carbon atoms, in particular having 8, 9 or 10 carbon atoms. Particularly preferred vinyl esters are derived from secondary and especially tertiary carboxylic acids whose branching is in the alpha position to the carbonyl group. Suitable vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl hexanoate, vinyl heptanoate, vinyl octanoate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl laurate, vinyl stearate and versatic acid esters such as vinyl neononanoate, vinyl neodecanoate, vinyl neoundecanoate.

In a further preferred embodiment, these ethylene copolymers contain vinyl acetate and at least one further vinyl ester of the formula 3 in which R ^{11 is} C ₄ to C ₃₀ -alkyl, preferably C ₄ to C ₁₆ -alkyl, especially C ₆ - to C ₁₂ -alkyl ,

The acrylic esters are preferably those of the formula 4

CH ₂ = CR ² -COOR ⁴ (4)

wherein R ^{2 is} hydrogen or methyl and R ^{4 is} C ₁ - to C ₃₀ -alkyl, preferably C ₄ - to C ₁₆ -alkyl, especially C ₆ - to C ₁₂ -alkyl. Suitable acrylic esters include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n- and isobutyl (meth) acrylate, hexyl, octyl, 2-ethylhexyl, decyl, dodecyl, tetradecyl , Hexadecyl, octadecyl (meth) acrylate and mixtures of these comonomers. In a further embodiment, said alkyl groups may be substituted with one or more hydroxyl groups. An example of such an acrylic ester is hydroxyethyl methacrylate.

The alkyl vinyl ethers are preferably compounds of the formula 5

CH ₂ = CH-OR ⁵ (5)

wherein R ^{5 is} C ₁ - to C ₃₀ -alkyl, preferably C ₄ - to C ₁₆ -alkyl, especially C ₆ - to C ₁₂ -alkyl. Examples which may be mentioned are methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether. In a further embodiment, said alkyl groups may be substituted with one or more hydroxyl groups.

The alkenes are preferably simple unsaturated hydrocarbons having 3 to 30 carbon atoms, especially 4 to 16 carbon atoms and especially 5 to 12 carbon atoms. Suitable alkenes include propene, butene, isobutylene, pentene, hexene, 4-methylpentene, octene, diisobutylene and norbornene and its derivatives such as methylnorbornene and vinylnorbornene. In a further embodiment, said alkyl groups may be substituted with one or more hydroxyl groups.

Particularly preferred terpolymers of 2-ethylhexanoic acid vinyl ester, vinyl neononanoate or vinyl neodecanoate contain, in addition to ethylene, preferably 3.5 to 20 mol%, in particular 8 to 15 mol% vinyl acetate and 0.1 to 12 mol%, in particular 0.2 to 5 mol% of the respective long-chain vinyl ester, wherein the total comonomer content is between 8 and 21 mol%, preferably between 12 and 18 mol%. Further particularly preferred copolymers contain, in addition to ethylene and 8 to 18 mol% of vinyl esters, 0.5 to 10 mol% of olefins such as propene, butene, isobutylene, hexene, 4-methylpentene, octene, diisobutylene and / or norbornene.

These ethylene copolymers and terpolymers preferably have melt viscosities at 140 ° C. of from 20 to 10,000 mPas, in particular from 30 to 5,000 mPas, especially from 50 to 2,000 mPas. The means of ¹ H-NMR spectroscopy, certain degrees of branching are preferably between 1 and 9 CH _3/100 CH ₂ groups, especially between 2 and 6 CH _3/100 CH ₂ groups, which do not stem from the comonomers.

In the case of mixtures of the additives according to the invention with ethylene copolymers (constituent II), the polymers underlying the mixtures differ in at least one characteristic. For example, they may contain different comonomers, have different comonomer contents, molecular weights and / or degrees of branching. Thus, for example, mixtures have proven particularly useful in which the Gesamtcomonomergehalt (the content of monomers other than ethylene) of the other ethylene copolymer at least two, in particular at least three mol% lower than that of the additive according to the invention. Furthermore, mixtures have proved particularly useful in which the average molecular weight Mw of the further ethylene copolymer is higher by at least 500 and in particular by at least 1000 g / mol than that of the additive according to the invention. The mixing ratio between the additives according to the invention and ethylene copolymers as constituent II can vary within wide limits, depending on the application, with the additives according to the invention often representing the greater proportion. Such additive mixtures preferably contain from 30 to 98% by weight, preferably from 50 to 97% by weight and especially from 70 to 95% by weight of the inventive additives and 2 to 70 wt .-%, preferably 3 to 50 wt .-% and especially 5 to 20 wt .-% ethylene copolymers (component II).

The suitable oil-soluble polar nitrogen compounds (ingredient III) are preferably reaction products of fatty amines with compounds containing an acyl group. The preferred amines are compounds of the formula NR ⁶ R ⁷ R ⁸ , in which R ⁶ , R ⁷ and R ^{8 may be} identical or different, and at least one of these groups is C ₈ -C ₃₆ -alkyl, C ₆ - C ₃₆ -cycloalkyl, C ₈ -C ₃₆ -alkenyl, in particular C ₁₂ -C ₂₄ -alkyl, C ₁₂ -C ₂₄ -alkenyl or cyclohexyl, and the other groups are either hydrogen, C ₁ -C ₃₆ -alkyl, C ₂ -C ₃₆ alkenyl, cyclohexyl, or a group of the formulas - (AO) _x -E or - (CH ₂ ) _n -NYZ, where A is an ethyl or propyl group, x is a number from 1 to 50, E = H, C ₁ -C ₃₀ -alkyl, C ₅ -C ₁₂ -cycloalkyl or C ₆ -C ₃₀ -aryl, and n = 2, 3 or 4, and Y and Z independently of one another are H, C ₁ -C ₃₀ Alkyl or - (AO) _x . The alkyl and alkenyl radicals can be linear or branched and contain up to two double bonds. They are preferably linear and substantially saturated, ie they have iodine numbers of less than 75 gl ₂ / g, preferably less than 60 gl ₂ / g and in particular between 1 and 10 gl ₂ / g. Particularly preferred are secondary fatty amines in which two of the groups R ⁶ , R ⁷ and R ^{8 are} C ₈ -C ₃₆ -alkyl, C ₆ -C ₃₆ -cycloalkyl, C ₈ -C ₃₆ -alkenyl, in particular C ₁₂ -C ₂₄ alkyl, C ₁₂ -C ₂₄ alkenyl or cyclohexyl. Suitable fatty amines are, for example, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, eicosylamine, behenylamine, didecylamine, didodecylamine, ditetradecylamine, dihexadecylamine, dioctadecylamine, dieicosylamine, dibehenylamine and mixtures thereof. Specifically, the amines contain chain cuts based on natural raw materials such as coco fatty amine, tallow fatty amine, hydrogenated tallow fatty amine, dicocosfettamine, ditallow fatty amine and di (hydrogenated tallow fatty amine). Particularly preferred amine derivatives are amine salts, imides and / or amides such as, for example, amide ammonium salts of secondary fatty amines, in particular dicocosfettamine, ditallow fatty amine and distearylamine.
By acyl group is meant here a functional group of the following formula:

> C = O

Suitable carbonyl compounds for the reaction with amines are both monomeric and polymeric compounds having one or more carboxyl groups. In the case of the monomeric carbonyl compounds, preference is given to those having 2, 3 or 4 carbonyl groups. They can also contain heteroatoms such as oxygen, sulfur and nitrogen. Examples of suitable carboxylic acids are maleic, fumaric, crotonic, itaconic, succinic, C ₁ -C ₄₀ -alkenylsuccinic, adipic, glutaric, sebacic, and malonic acids and benzoic, phthalic, trimellitic and pyromellitic acid, nitrilotriacetic acid , Ethylenediaminetetraacetic acid and their reactive derivatives such as esters, anhydrides and acid halides. Copolymers of ethylenically unsaturated acids, such as, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid, have proven particularly suitable as polymeric carbonyl compounds, particular preference is given to copolymers of maleic anhydride. Suitable comonomers are those which impart oil solubility to the copolymer. Oil-soluble means here that the copolymer dissolves without residue in the middle distillate to be additive after reaction with the fatty amine in practice-relevant metering rates. Suitable comonomers are, for example, olefins, alkyl esters of acrylic acid and methacrylic acid, alkyl vinyl esters and alkyl vinyl ethers having 2 to 75, preferably 4 to 40 and in particular 8 to 20 carbon atoms in the alkyl radical. In the case of olefins, the carbon number refers to the alkyl radical attached to the double bond. The molecular weights of the polymeric carbonyl compounds are preferably between 400 and 20,000, more preferably between 500 and 10,000, for example between 1,000 and 5,000.

Oil-soluble polar nitrogen compounds which have been obtained by reaction of aliphatic or aromatic amines, preferably long-chain aliphatic amines, with aliphatic or aromatic mono-, di-, tri- or tetracarboxylic acids or their anhydrides have proven particularly suitable (cf. US 4 211 534 ). Similarly, amides and ammonium salts of aminoalkylene polycarboxylic acids such as nitrilotriacetic acid or ethylenediaminetetraacetic acid with secondary amines are suitable as oil-soluble polar nitrogen compounds (cf. EP 0 398 101 ). Other oil-soluble polar nitrogen compounds are copolymers of maleic anhydride with α, β-unsaturated compounds, which can optionally be reacted with primary monoalkylamines and / or aliphatic alcohols (cf. EP-A-0 154 177 . EP 0 777 712 ), the reaction products of Alkenylspirobislactonen with amines (see. EP-A-0 413 279 B1 ) and after EP-A-0 606 055 A2 Reaction products of terpolymers based on α, β-unsaturated dicarboxylic acid anhydrides, α, β-unsaturated compounds and polyoxyalkylene ethers of lower unsaturated alcohols.

The mixing ratio between the additives according to the invention and oil-soluble polar nitrogen compounds as constituent III can vary depending on the application. Preferably, such additive mixtures contain 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, based on the active compounds, of at least one oil-soluble polar nitrogen compound per part by weight of the additive according to the invention.

Suitable alkylphenol-aldehyde resins as constituent IV are, in particular, those alkylphenol-aldehyde resins which are derived from alkylphenols having one or two alkyl radicals in ortho and / or para position to the OH group. Particularly preferred as starting materials are alkylphenols which carry at least two hydrogen atoms capable of condensation with aldehydes on the aromatic and in particular monoalkylated phenols. Particularly preferably, the alkyl radical is in the para position to the phenolic OH group. The alkyl radicals (which are understood as meaning in general hydrocarbon radicals as defined below for component IV) may be identical or different in the alkylphenol-aldehyde resins which can be used with the additives according to the invention. The alkyl radicals can be saturated or unsaturated. They can be linear or branched, preferably they are linear. They have 1 to 200, preferably 1 to 24, especially 4 to 16 such as 6 to 12 carbon atoms. It is preferably n-, iso- and tert-butyl, n- and iso-pentyl, n- and iso-hexyl, n- and iso-octyl, n- and iso-nonyl-, n - and iso-decyl, n- and iso-dodecyl, tetradecyl, hexadecyl, octadecyl, tripropenyl, tetrapropenyl, poly (propenyl) - and poly (isobutenyl) radicals. Particularly suitable alkylphenol-aldehyde resins are derived from linear alkyl radicals having 8 and 9 C atoms. In a preferred embodiment, mixtures of alkylphenols having different alkyl radicals are used for the preparation of the alkylphenol resins. For example, resins based on butylphenol have on the one hand and octyl, nonyl and / or dodecylphenol in the molar ratio of 1:10 to 10: 1 on the other hand, particularly useful.

Suitable alkylphenol resins may also contain or consist of structural units of other phenol analogs such as salicylic acid, hydroxybenzoic acid and derivatives thereof such as esters, amides and salts.

Suitable aldehydes for the alkylphenol-aldehyde resins are those having 1 to 12 carbon atoms and preferably those having 1 to 4 carbon atoms such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, 2-ethylhexanal, benzaldehyde, glyoxalic acid and their reactive equivalents such as paraformaldehyde and trioxane. Particularly preferred is formaldehyde in the form of paraformaldehyde, and especially formalin.

The molecular weight of the alkylphenol-aldehyde resins measured by gel permeation chromatography against poly (styrene) standards in THF is preferably 500-25,000 g / mol, more preferably 800-10,000 g / mol and especially 1,000-5,000 g / mol such as 1500-3,000 g / mol. The prerequisite here is that the alkylphenol-aldehyde resins, at least in application-relevant concentrations of 0.001 to 1 wt .-% are oil-soluble.

sind, worin R⁹ für C₁-C₂₀₀-Alkyl oder -Alkenyl, O-R¹⁰ oder O-C(O)-R¹⁰, R¹⁰ für C₁-C₂₀₀-Alkyl oder -Alkenyl und n für eine Zahl von 2 bis 100 stehen. R¹⁰ steht bevorzugt für C₁-C₂₄-Alkyl oder -Alkenyl und insbesondere für C₄-C₁₆-Alkyl oder -Alkenyl wie beispielsweise für C₆-C₁₂-Alkyl oder-Alkenyl. Besonders bevorzugt steht R⁹ für C₁-C₂₄-Alkyl oder -Alkenyl und insbesondere für C₄-C₁₆-Alkyl oder -Alkenyl wie beispielsweise für C₆-C₁₂-Alkyl oder -Alkenyl. Bevorzugt steht n für eine Zahl von 2 bis 50 und speziell für eine Zahl von 3 bis 25 wie beispielsweise eine Zahl von 5 bis 15.In a preferred embodiment of the invention, these are alkylphenol-formaldehyde resins, the oligo- or polymers having a repetitive structural unit of the formula

in which R ^{9 is} C ₁ -C ₂₀₀ -alkyl or -alkenyl, OR ¹⁰ or OC (O) -R ¹⁰ , R ^{10 is} C ₁ -C ₂₀₀ -alkyl or -alkenyl and n is a number from 2 to 100 stand. R ¹⁰ stands preferably C ₁ -C ₂₄ -alkyl or -alkenyl and in particular C ₄ -C ₁₆ -alkyl or -alkenyl such as, for example, C ₆ -C ₁₂ -alkyl or -alkenyl. With particular preference R ^{9 is} C ₁ -C ₂₄ -alkyl or -alkenyl and in particular C ₄ -C ₁₆ -alkyl or -alkenyl, for example C ₆ -C ₁₂ -alkyl or -alkenyl. Preferably, n is a number from 2 to 50 and especially a number from 3 to 25, such as a number from 5 to 15.

These alkylphenol-aldehyde resins are accessible by known methods, for example by condensation of the corresponding alkylphenols with formaldehyde, ie with 0.5 to 1.5 moles, preferably 0.8 to 1.2 moles of formaldehyde per mole of alkylphenol. The condensation can be carried out solvent-free, but preferably it is carried out in the presence of an inert or only partially water-miscible inert organic solvent such as mineral oils, alcohols, ethers and the like. Particularly preferred are solvents which can form azeotropes with water. As such solvents in particular aromatics such as toluene, xylene diethylbenzene and higher-boiling commercial solvent mixtures such as ^® Shellsol AB, and solvent naphtha are used. Also, fatty acids and their derivatives such as esters with lower alcohols having 1 to 5 carbon atoms such as ethanol and especially methanol are suitable as solvents. The condensation is preferably carried out between 70 and 200 ° C such as between 90 and 160 ° C. It is usually catalysed by 0.05 to 5 wt .-% bases or preferably by 0.05 to 5 wt .-% acids. As acidic catalysts in addition to carboxylic acids such as acetic acid and oxalic acid in particular strong mineral acids such as hydrochloric acid, phosphoric acid and sulfuric acid and sulfonic acids are common catalysts. Particularly suitable catalysts are sulfonic acids which contain at least one sulfonic acid group and at least one saturated or unsaturated, linear, branched and / or cyclic hydrocarbon radical having 1 to 40 C atoms and preferably having 3 to 24 C atoms. Particularly preferred are aromatic sulfonic acids, especially alkylaromatic mono-sulfonic acids having one or more C ₁ -C ₂₈ -alkyl radicals and in particular those having C ₃ -C ₂₂ -alkyl radicals. Suitable examples are methanesulfonic acid, butanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, 2-mesitylenesulfonic acid, 4-ethylbenzenesulfonic acid, isopropylbenzenesulfonic acid, 4-butylbenzenesulfonic acid, 4-octylbenzenesulfonic acid; Dodecylbenzenesulfonic acid, didodecylbenzenesulfonic acid, naphthalenesulfonic acid.

Mixtures of these sulfonic acids are suitable. Usually, these remain after completion of the reaction as such or in neutralized form in the product. For neutralization, amines and / or aromatic bases are preferably used, since they can remain in the product; Metal ions containing and thus ash-forming salts are usually separated.

beschrieben werden. Darin bedeuten

A

R', COOR', OCOR', R"-COOR', OR';

D

H, CH₃, A oder R";

E

H, A;

G

H, R", R"-COOR', einen Arylrest oder einen heterocyclischen Rest;

M

H, COOR", OCOR", OR", COOH;

N

H, R", COOR", OCOR", einen Arylrest;

R'

eine Kohlenwasserstoffkette mit 8 bis 50 Kohlenstoffatomen;

R"

eine Kohlenwasserstoffkette mit 1 bis 10 Kohlenstoffatomen;

m

eine Zahl zwischen 0,4 und 1,0; und

n

eine Zahl zwischen 0 und 0,6.

Suitable comb polymers (constituent V) may, for example, be represented by the formula

to be discribed. Mean in it

A

R ', COOR', OCOR ', R "-COOR', OR ';

D

H, CH _3, A or R ";

e

H, A;

G

H, R ", R" -COOR ', an aryl radical or a heterocyclic radical;

M

H, COOR ", OCOR", OR ", COOH;

N

H, R ", COOR", OCOR ", an aryl radical;

R '

a hydrocarbon chain of 8 to 50 carbon atoms;

R "

a hydrocarbon chain of 1 to 10 carbon atoms;

m

a number between 0.4 and 1.0; and

n

a number between 0 and 0.6.

Suitable comb polymers are, for example, copolymers of ethylenically unsaturated dicarboxylic acids such as maleic or fumaric acid with other ethylenically unsaturated monomers such as olefins or vinyl esters such as vinyl acetate. Particularly suitable olefins are α-olefins having 10 to 24 carbon atoms such as 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and mixtures thereof. Even longer-chain olefins based on oligomerized C ₂ -C ₆ -olefins such as poly (isobutylene) with a high proportion of terminal double bonds are suitable as comonomers. Usually, these copolymers become too At least 50% esterified with alcohols having 10 to 22 carbon atoms. Suitable alcohols include n-decan-1-ol, n-dodecan-1-ol, n-tetradecan-1-ol, n-hexadecan-1-ol, n-octadecan-1-ol, n-eicosan-1-ol and their mixtures. Particular preference is given to mixtures of n-tetradecan-1-ol and n-hexadecan-1-ol. Also suitable as comb polymers are poly (alkyl acrylates), poly (alkyl methacrylates) and poly (alkyl vinyl ethers) derived from alcohols having 12 to 20 carbon atoms and poly (vinyl esters) derived from fatty acids having 12 to 20 carbon atoms ,

Suitable polyoxyalkylene compounds (constituent VI) are, for example, esters, ethers and ethers / esters of polyols which carry at least one alkyl radical having 12 to 30 C atoms. When the alkyl groups are derived from an acid, the remainder is derived from a polyhydric alcohol; If the alkyl radicals come from a fatty alcohol, the remainder of the compound derives from a polyacid.

Suitable polyols are polyethylene glycols, polypropylene glycols, polybutylene glycols and their copolymers having a molecular weight of about 100 to about 5000, preferably 200 to 2000 g / mol. Also suitable are alkoxylates of polyols, such as, for example, glycerol, trimethylolpropane, pentaerythritol, neopentyl glycol, and the oligomers having from 2 to 10 monomer units obtainable therefrom by condensation, e.g. Polyglycerol. Preferred alkoxylates are those having from 1 to 100, in particular from 5 to 50, mol of ethylene oxide, propylene oxide and / or butylene oxide per mole of polyol. Esters are especially preferred.

Fatty acids containing 12 to 26 carbon atoms are preferred for reaction with the polyols to form the ester additives, more preferably C ₁₈ to C ₂₄ fatty acids, especially stearic and behenic acid. The esters can also be prepared by esterification of polyoxyalkylated alcohols. Preference is given to completely esterified polyoxyalkylated polyols having molecular weights of from 150 to 2,000, preferably from 200 to 600. Particularly suitable are PEG-600 dibehenate and glycerol-ethylene glycol tribehenate.

Suitable olefin copolymers (component VII) as further constituent of the additive according to the invention can be derived directly from monoethylenically unsaturated monomers or indirectly by hydrogenation of polymers which differ from derive polyunsaturated monomers such as isoprene or butadiene produced. In addition to ethylene, preferred copolymers contain structural units which are derived from α-olefins having 3 to 24 carbon atoms and have molecular weights of up to 120,000 g / mol. Preferred α-olefins are propylene, butene, isobutene, n-hexene, isohexene, n-octene, isooctene, n-decene, isodecene. The comonomer content of α-olefins having 3 to 24 carbon atoms is preferably between 15 and 50 mol%, more preferably between 20 and 35 mol% and especially between 30 and 45 mol%. These copolymers may also contain minor amounts, eg up to 10 mol% of other comonomers, such as non-terminal olefins or non-conjugated olefins. Preferred are ethylene-propylene copolymers. The olefin copolymers can be prepared by known methods, for example by Ziegler or metallocene Katatysatoren.

Other suitable olefin copolymers are block copolymers containing blocks of olefinically unsaturated aromatic monomers A and blocks of hydrogenated polyolefins B. Particularly suitable are block copolymers of the structure (AB) _n A and (AB) _m , where n is a number between 1 and 10 and m is a number between 2 and 10.

The mixing ratio between the additives according to the invention and alkylphenol-aldehyde resins (constituent IV), comb polymers (constituent V), polyoxyalkylene compounds (constituent VI) and olefin copolymers (constituent VII) can vary depending on the application. Such additive mixtures preferably contain 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, of at least one alkylphenol-aldehyde resin, a comb polymer, a polyoxyalkylene compound and / or an olefin copolymer per part by weight of the additive according to the invention.
The additives according to the invention can be used alone or together with other additives, for example with other pour point depressants or dewaxing aids, with antioxidants, cetane number improvers, dehazers, demulsifiers, detergents, dispersants, defoamers, colorants, corrosion inhibitors, lubricity additives, sludge inhibitors, odorants and / or Additions to Humiliation of the Cloud Point.

The additives according to the invention are suitable for improving the cold flow properties of animal, vegetable and / or mineral fuel oils. At the same time, these additives have very low properties and their concentrated formulations in mineral oil based solvents lead to low viscosity, clear formulations. This allows easy use of these additives, especially under conditions where the additives need to be used without the possibility of preheating at low temperatures, as may occur, for example, when used in remote regions in winter.

They are particularly suitable for improving the properties of mineral oils and mineral oil distillates such as jet fuel, kerosene, diesel and heating oil with low cloud points below 0 ° C, especially below -10 ° C such as below -15 ° C or below -20 ° C. In order to lower the sulfur content, they have often been subjected to hydrogenation refining and preferably contain less than 350 ppm sulfur, and more preferably less than 100 ppm sulfur, such as less than 50 ppm or 10 ppm sulfur. Furthermore, these oils preferably contain less than 25% by weight, in particular less than 22% by weight, for example less than 20% by weight of aromatic compounds.

The fuel oils according to the invention preferably contain 5 to 5,000 ppm, more preferably 10 to 2,000 ppm and especially 50 to 1,000 ppm of at least one terpolymer of ethylene, unsaturated ester and propene according to the invention.

The middle distillate is in particular those mineral oils which are obtained by distillation of crude oil and boil in the range of 120 to 450 ° C, for example kerosene, jet fuel, diesel and fuel oil. The compositions according to the invention are particularly advantageous in such middle distillates, having 90% distillation points below 360 ° C., in particular 350 ° C. and in special cases below 340 ° C. Middle distillates also include synthetic fuel oils boiling in the temperature range of about 120 to 450 ° C and mixtures of mineral and these synthetic middle distillates. Examples of synthetic middle distillates are in particular by the Fischer-Tropsch process from coal, Natural gas or biomass produced fuels. Synthesis gas is first produced and this is converted into normal paraffins via the Fischer-Tropsch process. The normal paraffins thus prepared can then be modified, for example, by catalytic cracking, isomerization, hydrocracking or hydrosiomerization.

By aromatic compounds is meant the sum of mono-, di- and polycyclic aromatic compounds as determinable by HPLC according to DIN EN 12916 (2001 edition).

The additive mixtures according to the invention are also particularly effective in middle distillates which contain minor amounts, for example up to 30% by volume, of oils of animal and / or vegetable origin. Examples of suitable oils of animal and / or plant origin are both triglycerides and esters derived therefrom with lower alcohols having 1 to 5 carbon atoms such as ethyl and in particular methyl esters, for example, from cotton, palm kernels, rapeseed, soy, sunflower, tallow and the like are accessible.

Examples Effectiveness of the additives as cold flow improvers

The superior efficacy of the inventive additives for mineral oils and mineral oil distillates is described by means of the CFPP test (Cold Filter Plugging Test according to EN 116).

The following additives were used: Characterization of the ethylene copolymers used

Process A): In a continuously operated tubular reactor were ethylene, propene and vinyl acetate at 200 MPa and a peak temperature of 220 ° C under Addition of the molecular weight regulator indicated in Table 1 copolymerized. The resulting polymer was separated from the reaction mixture and then freed of residual monomers.

Method B): In a continuously operated high-pressure autoclave, ethylene, vinyl acetate and propylene were copolymerized by adding a 10% by weight solution of bis (2-ethylhexyl) peroxydicarbonate as an initiator and the molecular weight regulator shown in Table 1. The resulting polymer was separated from the reaction mixture and then freed of residual monomers.

For comparison, an ethylene-vinyl acetate copolymer (Ex. 24), a terpolymer of ethylene, vinyl acetate and propene were used according to EP 0 190 553 (Ex. 25), a terpolymer of ethylene, vinyl acetate and 4-methylpentene-1 according to EP 0 807 642 (Ex. 26) and a terpolymer of ethylene, vinyl acetate and isobutylene (Ex 27).

The vinyl acetate content is determined by means of pyrolysis of the polymer freed from residual monomers at 150 ° C./100 mbar. For this purpose, 100 mg of the polymer are thermally split with 200 mg of pure polyethylene in a pyrolysis flask for 5 minutes at 450 ° C in a closed system under vacuum and collected the fission gases in a 250 ml round bottom flask. The cleavage product acetic acid is reacted with a NaJ / KJO ₃ solution and titrated with Na ₂ S ₂ O ₃ solution, the liberated iodine.

The determination of the total number of non-vinyl ester methyl groups of the polymer by means of ¹ H-NMR spectroscopy at a measurement frequency of 500 MHz at 10 to 15% solutions in C ₂ D ₂ Cl ₄ at 300 K. The integral of the methyl protons between about 0.7 to 0.9 ppm is related to that of the methylene and methine protons between about 0.9 and 1.9 ppm. A correction of the number of methyl groups around the structural units derived from the moderator used and superposed with the signals of the polymer main chain is based on the separately appearing methine proton of the moderator (for example, methyl ethyl ketone and propanal multiplet at 2.4 and 2.5 ppm).

The determination of the content of methyl groups derived from propene is carried out by means of ¹³ C-NMR spectroscopy at a measurement frequency of 125 MHz at also 10 to 15% solutions in C ₂ D ₂ Cl ₄ at 300 K. The integral of the Propene-derived methyl groups between 19.3 and 20.2 ppm are proportioned to that of the aliphatic carbon atoms of the polymer backbone between 22 and 44 ppm. Advantageously, ¹ H and ¹³ C NMR measurements are carried out on the same sample.

The number of chain ends is determined by subtracting the number of methyl groups derived from propene by ¹³ C-NMR from the total number of methyl groups determined by ¹ H-NMR. Both values are to be treated as dimensionless numbers.

To assess the cold flowability of concentrates containing additives of the invention, the above-listed active ingredients were 35% in higher boiling aromatic solvent (solvent naphtha) homogenized with stirring at 60 ° C. Subsequently, the pour point of the resulting concentrate was determined. Table 1: Characterization of the polymers polymer Polymerization process / moderator Vinyl acetate in the polymer [mol%] Propene-CH ₃ per 100 aliph. CH ₂ Number of chain ends Total G V ₁₄₀ [mPas] Pour point [° C] P1 A / PA 13.5 3.0 6.2 16.5 155 -27 P2 B / PA 13.4 2.6 4.7 16.0 182 -33 P3 B / PA 13.6 3.0 4.9 16.6 140 -39 P4 B / PA 12.2 3.1 5.2 15.3 115 -36 P5 B / PA 13.4 1.8 4.1 15.2 143 -27 P6 B / PA 14.9 1.6 4.6 16.5 148 -30 P7 B / PA 14.0 2.2 3.8 16.2 95 -21 P8 B / PA 13.8 2.8 3.9 16.6 90 -27 P9 B / PA 14.4 3.4 3.6 17.8 88 -30 P10 B / PA 13.5 2.3 3.4 15.8 103 -18 P11 B / PA 13.3 2.6 4.2 15.9 156 -27 P12 B / PA 13.8 3.1 4.4 16.9 147 -33 P13 B / PA 14.1 3.6 4.8 17.7 99 -36 P14 A / MEK 13.5 2.9 4.3 16.4 175 -24 P15 A / MEK 13.5 2.0 5.4 15.5 155 -18 P16 A / MEK 14.4 2.8 4.8 17.2 153 -21 P17 A / MEK 14.0 2.2 5.2 16.2 157 -27 P18 B / PA 14.3 2.2 3.6 16.5 97 -21 P19 B / PA 14.0 2.9 3.2 16.9 154 -24 P20 B / MPK 14.9 1.2 5.3 16.1 104 -18 P21 (Cf.) B / PA 13.7 4.2 5.8 17.9 138 -48 P22 (Cf.) B / PA 16.2 2.5 5.8 18.6 138 -42 P23 (Cf.) B / PA 13.6 2.7 6.7 17.3 133 -39 P24 (Cf.) A / MEK 13.3 - 4.6 13.3 125 -9 P25 (Cf.) B / - 12.8 12.0 6.9 18.9 145 -21 P26 (Cf.) B / PA 12.5 4.6 mol% 4-MP-1 n / A n / A 115 -24 P27 (Cf.) B / PA 13.1 4.3 mol% DIB n / A n / A 122 -27 PA = propionaldehyde; MEK = methyl ethyl ketone; MPK = methyl propyl ketone The test oils used were current oils from European refineries. The CFPP value was determined in accordance with EN 116 and the determination of the cloud point in accordance with ISO 3015. Test oil 1 Test oil 2 Test oil 3 Test oil 4 distillation IBP [° C] 200 194 188 171 20% [° C] 251 249 232 218 90% [° C] 342 341 323 324 FBP [° C] 357 355 355 351 Cloud Point [° C] -4.2 -5.6 -18 -5.4 CFPP [° C] -6 -7 -20 -8th Density @ 15 ° C [g / cm ³ ] .8433 0,840 0,852 0.831 example polymer metering 100 ppm 200 ppm 300 ppm 1 P1 -7 -10 -18 2 P2 -11 -14 -17 3 P3 -10 -18 -20 4 P4 -11 -19 -21 5 P7 -11 -20 -21 6 P8 -11 -16 -21 7 P9 -7 -12 -18 8th P10 -12 -22 -21 9 P11 -10 -17 -21 10 P12 -9 -17 -20 11 P13 -11 -19 -21 12 P14 -10 -19 -19 13 P15 -11 -18 -21 14 P16 -12 -20 -22 15 P17 -10 -18 -19 16 P18 -12 -19 -21 17 P19 -11 -20 -22 18 P20 -10 -17 -20 19 P21 (Cf.) -9 -10 -10 20 P22 (Cf.) -7 -7 -8th 21 P23 (Cf.) -7 -8th -8th 22 P24 (Cf.) -11 -17 -19 23 P25 (Cf.) -7 -10 -11 24 P26 (Cf.) -8th -10 -13 The effectiveness of the terpolymers according to the invention in test oil 2 was determined in combination of 75% by weight of the polymers according to the invention with 25% by weight of an ethylene copolymer with 24% by weight of vinyl acetate and a melt viscosity of 280 mPas measured at 140 ° C. example polymer metering 100 ppm 200 ppm 300 ppm 25 P1 -9 -14 -18 26 P2 -11 -19 -21 27 P4 -10 -15 -21 28 P5 -11 -19 -20 29 P6 -10 -17 -20 30 P7 -11 -19 -21 31 P8 -11 -18 -21 32 P9 -10 -16 -20 33 P16 -10 -16 -20 34 P17 -11 -17 -20 35 P20 -10 -14 -20 36 P21 (Cf.) -10 -12 -15 37 P22 (Cf.) -11 -12 -15 38 P23 (Cf.) -11 -11 -13 39 P24 (Cf.) -10 -18 -20 40 P25 (Cf.) -10 -11 -15 41 P27 (Cf.) -11 -13 -17

The effectiveness of the terpolymers according to the invention was determined in the test oils 3 and 4 in a combination of 85% by weight of the polymers according to the invention with 15% by weight of a condensate of alkylphenol and formaldehyde having an average molecular weight of 12,000 g / mol. Table 5: Test as cold flow improver in test oil 3 example polymer metering 25 ppm 50 ppm 100 ppm 42 P2 -33 -35 -36 43 P6 -33 -34 -37 44 P7 -34 -33 -36 45 P8 -34 -35 -38 46 P14 -33 -34 -35 47 P16 -34 -34 -35 48 P17 -32 -33 -35 49 P19 -35 -38 -39 50 P25 (Cf.) -25 -27 -28 51 P27 (Cf.) -29 -31 -32 example polymer metering 300 ppm 400 ppm 500 ppm 52 P4 -12 -12 -18 53 P5 -12 -18 -19 54 P6 -12 -19 -20 55 P7 -19 -19 -19 56 P8 -17 -20 -18 57 P11 -12 -19 -19 58 P12 -12 -18 -18 59 P13 -12 -15 -18 60 P15 -12 -14 -16 61 P16 -12 -17 -19 62 P22 (Cf.) -11 -12 -12 63 P23 (Cf.) -11 -11 -12 64 P26 (Cf.) -11 -13 -15

The experiments show that the additives according to the invention are superior to the additives of the prior art in terms of improving the cold flowability and in particular the CFPP reduction of middle distillates. At the same time, their concentrates can be used at lower temperatures than corresponding copolymers of ethylene and vinyl esters.

Claims (20)

1. A terpolymer of ethylene, at least one ethylenically unsaturated ester and propene, which

   a) contains from 12.0 to 16.0 mol% of structural units derived from at least one ethylenically unsaturated ester,

   b) contains from 1.0 to 4.0 methyl groups bonded to the polymer backbone and derived from propene per 100 aliphatic carbon atoms, and

   c) has fewer than 6.5 methyl groups steaming from chain ends per 100 CH₂ groups.
2. The polymer as claimed in claim 1, in which the ethylenically unsaturated ester is the vinyl ester of a carboxylic acid having from 2 to 12 carbon atoms.
3. The polymer as claimed in claim 1 or 2, in which the ethylenically unsaturated ester is vinyl acetate.
4. The polymer as claimed in claim 3, in which the vinyl acetate content is between 28.0 and 36.0% by weight.
5. The polymer as claimed in one or more of claims 1 to 4, in which the sum G of molar content of unsaturated ester a) and the number of methyl groups derived from propene per 100 aliphatic carbon atoms of the polymer b) $$\mathrm{G}=\left[\mathrm{mol}\%\mathrm{of\; unsaturated\; ester}\right]+\left[\mathrm{propene}-{\mathrm{CH}}_{\mathrm{3}}\right]$$

   

   
   is between 14.5 and 18.0.
6. The polymer as claimed in one or more of claims 1 to 5, which additionally contains structural units derived from at least one moderator comprising a carbonyl group.
7. The polymer as claimed in claim 6, which contains from 0.5 to 7.0% by weight of at least one structural unit derived from a moderator comprising carbonyl groups.
8. A process for preparing a polymer as claimed in one or more of claims 1 to 7, by reacting a mixture of ethylene, propene and at least one vinyl ester under elevated pressure and elevated temperature in the presence of a free radical-forming initiator, and in which the molecular weight is adjusted by a moderator comprising carbonyl groups.
9. The process as claimed in claim 8, in which a high-pressure bulk polymerization is performed at pressures of at least 100 MPa.
10. The process as claimed in claim 8 or 9, in which a high-pressure bulk polymerization is performed at peak temperatures below 220°C.
11. A composition comprising at least one polymer as claimed in one or more of claims 1 to 7 and at least one different ethylene copolymer.
12. The composition as claimed in claim 11, wherein the total comonomer content of the further ethylene copolymer is at least two mol% lower than that of the polymer as claimed in claims 1 to 7.
13. A composition comprising at least one polymer as claimed in one or more of claims 1 to 7 or a composition as claimed in claim 11 or 12 and at least one oil-soluble polar nitrogen compound.
14. A composition comprising at least one polymer as claimed in one or more claims 1 to 7 or a composition as claimed in claim 11, 12 or 13 and at least one alkylphenol-aldehyde resin.
15. A composition comprising at least one polymer as claimed in one or more of claims 1 to 7 or a composition as claimed in claim 11, 12, 13 or 14 and at least one comb polymer.
16. The composition as claimed in one or more of the preceding claims, comprising at least one polymer as claimed in one or more of claims 1 to 7 or a composition as claimed in claim 11, 12, 13, 14 or 15 and at least one polyoxyalkylene compound.
17. The use of a terpolymer as claimed in one or more of the preceding claims 1 to 7 for improving the cold flow properties of mill distillates.
18. A free-flowing additive concentrate having an intrinsic pour point of -10°C or lower for improving the flowability of middle distillates, containing 20-40% by weight of at least one terpolymer as claimed in one or more of claims 1 to 7 and 60-80% by weight of at least one solvent.
19. A process for improving the cold flow properties of a fuel oil, by adding to the fuel oil a formulation containing at least 20% by weight of at least one terpolymer as claimed in one or more of claims 1 to 7 at a temperature of 0°C or lower.
20. A fuel oil comprising a middle distillate and at least one polymer as claimed in one or more of claims 1 to 7.