EP0900836B1 - Additive for mineral oils and mineral oil distillates flowability improvement - Google Patents

Abstract

The additive comprises a mixture containing either and/or ester as solvent agent. An additive to improve the flowability of paraffin-containing mineral oil distillate comprises a mixture containing an ethylene/vinylester co- or terpolymer and at least one paraffin disperser. The ether is of formula R-O-R', where R = 4-30C linear or branched alkyl or alkenyl groups and R' = 1-30C linear or branched alkyl or alkenyl groups. The ester is one or more CO(s) with 4-30C )oxygen residue) and one or more alcohol with 1-30C (alcohol residue). The ether and/or ester is/are cyclic, having a ring size of 6-30C. An Independent claim is also included for improving the flowability of mineral oils and mineral oil distillate.

Description

The invention relates to an additive for improving the flowability of mineral oils and mineral oil distillates containing paraffin and containing flow improvers based on ethylene-vinyl ester copolymers and terpolymers, polar Nitrogen compounds and ethers and / or esters as solubilizers.

Crude oils and middle distillates obtained by distilling crude oils such as gas oil, Diesel oil or heating oil contain different amounts depending on the origin of the crude oils on n-paraffins which, when the temperature is lowered, form platelet-shaped crystals crystallize out and partially agglomerate with the inclusion of oil. Through this Crystallization and agglomeration worsen Flow properties of the oils or distillates, which means during extraction, transport, Storage and / or use of mineral oils and mineral oil distillates may occur. This can happen when transporting mineral oils through pipes Crystallization phenomenon, especially in winter, to deposits on the tube walls, in individual cases, e.g. B. when a pipeline is at a standstill, even for its complete blockage to lead. When storing and processing mineral oils, it can also be stored in In winter it may be necessary to store the mineral oils in heated tanks. at Mineral oil distillates may occur as a result of crystallization Clogging of the filters in diesel engines and combustion plants, causing a safe dosing of the fuels is prevented and possibly a complete The fuel or heating medium supply is interrupted.

In addition to the classic methods for removing the crystallized paraffins (thermal, mechanical or with solvents) that only affect the Removal of the precipitates already formed have been made in the last Years of chemical additives (so-called flow improvers) have been developed. This effect through physical interaction with the failing Paraffin crystals that modify their shape, size and adhesive properties become. The additives act as additional crystal nuclei and crystallize partially with the paraffins, causing a larger number of smaller ones Paraffin crystals with a changed crystal shape are formed. The modified Paraffin crystals are less prone to agglomeration, so that they deal with them Additive-added oils can be pumped or processed at temperatures, which are often more than 20 ° lower than with non-additive oils.

Typical flow improvers for crude oils and middle distillates are copolymers and terpolymers of ethylene with carboxylic acid esters of vinyl alcohol.

Another task of flow improver additives is to disperse the failed paraffin crystals, i.e. the delay or prevention of Sedimentation of the paraffin crystals and thus the formation of a paraffin-rich Layer on the bottom of storage containers.

In the prior art, among other things, polar nitrogen compounds Paraffin dispersants are known, which together with Co or Terpolymers of ethylene and vinyl esters for the additive of mineral oils and Mineral oil distillates can be used.

The desired use of concentrates from polar in many cases Nitrogen compounds as paraffin dispersants together with Co and Terpolymers made from ethylene and vinyl esters, however, come up against technical ones Difficulties because these substances are very poorly soluble in one another. in the State of the art, various solubilizers are therefore proposed However, the effect is often unsatisfactory.

DE-A-40 19 623 discloses crystallization inhibitors for paraffins in petroleum fractions, that from fatty amines and solutions of benzoic or formic acid in methanol, Ethanol, cyclohexanol or isopropanol exist.

EP-A-0 104 015 discloses the use of weak organic acids, especially aromatic acids such as benzoic acid, alkylphenols and Alkarylsulfonic acids to improve the solubility of nitrogen compounds in Oil.

US 4,210,424 discloses the use of polymers derived from carboxylic acid esters and bearing alkyl side chains of 6 to 30 carbon atoms and / or of C ₈ -C ₁₈ alkanols as solubilizers in compositions of ethylene copolymers, paraffin waxes and nitrogen compounds.

EP-A-0 733 694 discloses solvent mixtures of aliphatic or alicyclic Alcohols with at least 4 carbon atoms and aromatic Hydrocarbons in a ratio of 10: 1 to 1: 2. The solvents are used to combine with oil-soluble additives containing NR groups, where R is is a hydrocarbon residue of 8 to 40 carbon atoms, a homogeneous To form mixture.

A) herkömmlicher Fließverbesserer auf Ethylenbasis und

B) Copolymere, die

a) zu 10 bis 90 mol-% aus einem oder mehreren Alkylacrylaten oder Alkylmethacrylaten mit C₁- bis C₃₀-Alkylketten und

b) zu 5 bis 60 mol-% aus einer oder mehreren ethylenisch ungesättigter Dicarbonsäuren oder deren Anhydride und

c) zu 5 bis 60 mol-% aus einem oder mehreren Alkylvinylethem mit C₁₈bis C₂₈-Alkylseitenketten bestehen

und das Gewichtsverhältnis von A zu B zu 60 bis 95 zu 5 beträgt, welche Phthalate enthalten können. EP-A-0 485 774 discloses petroleum middle distillates with improved flow properties in the cold, containing small amounts

A) conventional ethylene based flow improver and

B) copolymers that

a) 10 to 90 mol% of one or more alkyl acrylates or alkyl methacrylates with C ₁ - to C ₃₀ -alkyl chains and

b) 5 to 60 mol% of one or more ethylenically unsaturated dicarboxylic acids or their anhydrides and

c) consist of 5 to 60 mol% of one or more alkyl vinyl ethers with C ₁₈ to C ₂₈ alkyl side chains

and the weight ratio of A to B is 60 to 95 to 5, which may contain phthalates.

EP-A-0 398 101 discloses reaction products of aminoalkylene polycarboxylic acids with secondary amines and their use as an additive to middle distillates optionally together with known as flow improvers Ethylene copolymers and conductivity improvers, with 2-EH phthalate can be included.

The task was therefore to find more efficient solvent mediators between the polar ones Find nitrogen compounds and the ethylene / vinyl ester copolymers and terpolymers.

Surprisingly, it was found that ethers and esters and their Blends excellent solubilizers for this Are flow improver compositions.

a) die Ether der Formel 1 entsprechen R - O - R' worin R für lineare oder verzweigte Alkyl- oder Alkenylgruppen mit 4 bis 30 Kohlenstoffatomen und R' für lineare oder verzweigte Alkyl- oder Alkenylgruppen mit 1 bis 30 Kohlenstoffatomen steht,

b) die Ester sich von ein- oder mehrwertigen Carbonsäuren mit linearen oder verzweigten Alkyl- oder Alkenylgruppen mit 5 bis 22 Kohlenstoffatomen (Säurerest) und von ein- oder mehrwertigen Alkoholen mit linearen oder verzweigten Alkyl- oder Alkenylgruppen mit 2 bis 22 Kohlenstoffatomen (Alkoholrest) ableiten, oder

c) die Ether und/oder Ester cyclisch sind, wobei R und R' bzw. der Säure- und Alkoholrest einen Ring mit 8 bis 22 Ringgliedern bilden.

The invention relates to an additive to improve the flowability of paraffin-containing mineral oils and mineral oil distillates, comprising a mixture of at least one ethylene-vinyl ester co- or terpolymer and at least one nitrogen-containing paraffin dispersant, which is a polar, low-molecular or polymeric oil-soluble compound, one or more of which at least one C ₈ -C ₂₆ alkyl chain contains substituted ester, amide and / or imide groups, and / or carries one or more ammonium groups derived from amines with one or two C ₈ -C ₂₆ alkyl groups, characterized in that that said mixture contains ether and / or ester as solubilizer, wherein

a) the ethers of formula 1 correspond R - O - R ' in which R represents linear or branched alkyl or alkenyl groups having 4 to 30 carbon atoms and R 'represents linear or branched alkyl or alkenyl groups having 1 to 30 carbon atoms,

b) the esters are derived from mono- or polyvalent carboxylic acids with linear or branched alkyl or alkenyl groups with 5 to 22 carbon atoms (acid residue) and from mono- or polyhydric alcohols with linear or branched alkyl or alkenyl groups with 2 to 22 carbon atoms (alcohol residue) deduce, or

c) the ethers and / or esters are cyclic, where R and R 'or the acid and alcohol radical form a ring with 8 to 22 ring members.

Another object of the invention is a method for improving the Flowability of mineral oils and mineral oil distillates, characterized in that that the additive according to the invention is added to them.

R and the acid residue are preferably linear or branched alkyl or Alkenyl groups with 5 to 22 carbon atoms. R 'and the alcohol residue preferably for linear or branched alkyl or alkenyl groups with 2 to 22 Carbon atoms.

Examples of ethers are dihexyl ether, dioctyl ether, di (2-ethylhexyl) ether, and Examples of esters are oleic acid eicosyl ester, 2-ethylhexyl stearate, 2-ethylhexyl acid butyrate, ethyl octanoate, ethyl hexanoate, 2-ethylhexyl butyl ester, 2-ethyl hexyl butyrate and 2-ethyl hexyl acid 2-ethyl hexyl ester called.

If the solubilizers are esters, the use of monound Diesters of both dialcohols and dicarboxylic acids are preferred. As Examples of esters are adipic acid di (2-ethylhexyl ester), 2-ethylhexanediol (1,3) mono-n-butyrate, Called 2-ethylhexanediol (1,3) di-n-butyrate.

It is further preferred to add up to 30% by weight of alkylphenol aldehyde resins and / or up to 10% by weight of alcohols, aldehydes and / or acetals (in each case based on the entire preparation) to the additive in addition to the ethers and / or esters , The mixtures can also contain aliphatic and / or aromatic solvents.
In a preferred embodiment of the invention, mixtures containing ether and ester, such as those formed as a by-product in oxosynthesis, are used.

In a further preferred embodiment of the invention, one of the Oxosynthesis originating, hereinafter referred to as MS Solvent mixture added as a solubilizer.

MS is a mixture of a number of aliphatic and cyclic, non-aromatic hydrocarbons. The main components of MS can be found in the following table: component Concentration range (% by weight) Di-2-ethylhexyl 10 - 25 2-ethylhexyl acid-2-ethylhexyl 10 - 25 C ₁₆ lactones 4 - 20 2-Ethylhexylbutyrat 3 - 10 2-ethylhexanediol- (1,3) glycol mono-n-butyrate 5 - 15 2-ethylhexanol 4 - 10 C ₄ to C ₈ acetals 2 - 10 2-ethylhexanediol- (1,3) 2 - 5 Ethers and esters ≥ C ₂₀ 0 - 20

Ethylen-Vinylacetat-Copolymere mit 10- 40 Gew.-% Vinylacetat und 60 - 90 Gew.-% Ethylen;

die aus DE-A-34 43 475 bekannten Ethylen-Vinylacetat-Hexen-Terpolymere;

die in EP-A-0 203 554 beschriebenen Ethylen-Vinylacetat-Diisobutylen-Terpolymere;

die aus EP-A-0 254 284 bekannte Mischung aus einem Ethylen-Vinylacetat-Diisobutylen-Terpolymerisat und einem EthylenNinylacetat-Copolymer;

die in EP-A-0 405 270 offenbarten Mischungen aus einem Ethylen-Vinylacetat-Copolymer und einem Ethylen-Vinylacetat-N-Vinylpyrrolidon-Terpolymerisat;

die in EP-A-0 463 518 beschriebenen Ethylen/Vinylacetat/i-Butylvinylether-Terpolymere;

die in EP-A-0 491 225 offenbarten Mischpolymerisate des Ethylens mit Alkylcarbonsäurevinylestern;

die aus EP-A-0 493 769 bekannten Ethylen/Vinylacetat/ Neononansäurevinylester bzw. Neodecansäurevinylester-Terpolymere, die außer Ethylen 10-35 Gew.-% Vinylacetat und 1 - 25 Gew.-% der jeweiligen Neoverbindung enthalten;

die in DE-A-196 20 118 beschriebenen Terpolymere aus Ethylen, dem Vinylester einer oder mehrerer aliphatischer C₂-C₂₀-Monocarbonsäuren und 4-Methylpenten-1; und

die in der nicht vorveröffentlichten deutschen Patentanmeldung mit dem Aktenzeichen 196 20 119.5 offenbarten Terpolymere aus Ethylen, dem Vinylester einer oder mehrerer aliphatischer C₂-C₂₀-Monocarbonsäuren und Bicyclo[2.2.1]hept-2-en.

All known copolymers or terpolymers of this type and their mixtures can be used as ethylene / vinyl ester copolymers or terpolymers, which by themselves improve the cold flow properties of mineral oils or mineral oil distillates. Examples of suitable copolymers or terpolymers are:

Ethylene-vinyl acetate copolymers with 10-40% by weight of vinyl acetate and 60-90% by weight of ethylene;

the ethylene-vinyl acetate-hexene terpolymers known from DE-A-34 43 475;

the ethylene-vinyl acetate-diisobutylene terpolymers described in EP-A-0 203 554;

the mixture known from EP-A-0 254 284 of an ethylene-vinyl acetate-diisobutylene terpolymer and an ethylene-vinyl acetate copolymer;

the mixtures of an ethylene-vinyl acetate copolymer and an ethylene-vinyl acetate-N-vinylpyrrolidone terpolymer disclosed in EP-A-0 405 270;

the ethylene / vinyl acetate / i-butyl vinyl ether terpolymers described in EP-A-0 463 518;

the copolymers of ethylene with alkylcarboxylic acid vinyl esters disclosed in EP-A-0 491 225;

the ethylene / vinyl acetate / neononanoic acid vinyl ester or neodecanoic acid vinyl ester terpolymers known from EP-A-0 493 769, which, in addition to ethylene, contain 10-35% by weight of vinyl acetate and 1-25% by weight of the respective neo compound;

the terpolymers described in DE-A-196 20 118 made of ethylene, the vinyl ester of one or more aliphatic C ₂ -C ₂₀ monocarboxylic acids and 4-methylpentene-1; and

the terpolymers of ethylene, the vinyl ester of one or more aliphatic C ₂ -C ₂₀ monocarboxylic acids and bicyclo [2.2.1] hept-2-enes disclosed in the unpublished German patent application with the file number 196 20 119.5.

Such ethylene-vinyl ester copolymers or terpolymers with a Ethylene content of 60-90% by weight and their mixtures.

aufweisen, worin R³ für gesättigtes, verzweigtes C₆-C₁₆-Alkyl steht, das ein tertiäres Kohlenstoffatom aufweist. Die für die Additivmischung verwendeten Co- und Terpolymere können neben den genannten Monomereinheiten auch noch bis zu 5 Mol-% von Monomereinheiten enthalten, die sich von Olefinen wie etwa Vinylether, Acrylsäurealkylester, Methacrylsäurealkylester, Isobutylen oder von höheren Olefinen mit mindestens 5 Kohlenstoffatomen wie beispielsweise Hexen, 4-Methylpenten, Octen oder Diisobutylen ableiten. Particularly preferred terpolymers of ethylene and vinyl esters are those which, in addition to 65 to 94 mol% of the structural units derived from ethylene and 5 to 35 mol% of vinyl acetate, also contain 1 to 25 mol% of structural units of the formula (2)

have, wherein R ^{3 is} saturated, branched C ₆ -C ₁₆ alkyl which has a tertiary carbon atom. In addition to the monomer units mentioned, the copolymers and terpolymers used for the additive mixture can also contain up to 5 mol% of monomer units derived from olefins such as vinyl ethers, alkyl acrylates, alkyl methacrylates, isobutylene or higher olefins with at least 5 carbon atoms such as, for example, hexene , 4-methylpentene, octene or diisobutylene.

• eine oder mehrere mit mindestens einer C₈-C₂₆-Alkylkette substituierte Ester-, Amid- und/oder Imidgruppen enthalten
• und/oder eine oder mehrere Ammoniumgruppen tragen, die sich von Aminen mit einer oder zwei C₈-C₂₆-Alkylgruppen ableiten.

Suitable paraffin dispersants are, for example, polar, low molecular weight or polymeric oil-soluble compounds which

• contain one or more ester, amide and / or imide groups substituted with at least one C ₈ -C ₂₆ alkyl chain
• and / or carry one or more ammonium groups derived from amines with one or two C ₈ -C ₂₆ alkyl groups.

Of the above-mentioned paraffin dispersants, the polar ones are preferred nitrogenous compounds.

As monomeric polar nitrogen-containing compounds, for example following substances are used:

EP-A-0 413 279 describes suitable reaction products of Alkenylspirobislactones with amines are described.

The oil-soluble reaction products of phthalic anhydride with amines disclosed in EP-A-0 061 894 can also be used in a mixture with ethylene-vinyl acetate copolymers.
Furthermore, the reaction products of aminoalkylene carboxylic acids with primary or secondary amines known from EP-A-0 597 278 are suitable as monomeric nitrogen-containing compounds.

Die aus EP-A-0 154 177 bekannten Umsetzungsprodukte von alternierenden Copolymeren auf der Basis von α,β-ungesättigten Verbindungen und Maleinsäureanhydrid mit primären Monoalkylaminen und aliphatischen Alkoholen;

die aus EP-A-0 436 151 bekannten Umsetzungsprodukte von Copolymeren auf der Basis von Maleinsäureanhydrid und α,β-ungesättigten Verbindungen wie Styrol mit Dialkylaminen;

die in EP-A-0 283 293 offenbarten Copolymere auf der Basis von aliphatischen Olefinen und Maleinsäureanhydrid, wobei das Copolymere sowohl Ester- als auch Amidgruppen aufweist, von denen jede eine Alkylgruppe mindestens 10 Kohlenstoffatome enthält;

die aus EP-A-0 436 151 bekannten Umsetzungsprodukte von Copolymeren auf der Basis von Maleinsäureanhydrid und α,β-ungesättigten Verbindungen wie Styrol mit Dialkylaminen;

die in EP-A-0 606 055 beschriebenen Terpolymere auf der Basis von α,β-ungesättigten Dicarbonsäureanhydriden, α,β-ungesättigten Verbindungen und Polyoxyalkylenethern von niederen, ungesättigten Alkoholen;

die aus EP-A-0 688 796 bekannten Copolymere auf der Basis von α,β-ungesättigten Olefinen mit mindestens 3 C-Atomen und α,β-ungesättigten Dicarbonsäureanhydriden, wobei die Dicarbonsäureanhydrideinheiten durch polymeranaloge Umsetzung mit Polyetheraminen oder Alkanolaminen in Imid-, Amid- und Ammonium-Einheiten überführt wurden;

die in der nicht vorveröffentlichten deutschen Patentanmeldung mit dem Aktenzeichen 196 45 603.7 beschriebenen statistischen Co- und Terpolymere auf der Basis von Ethylen, α,β-ungesättigten Dicarbonsäureanhydriden sowie gegebenenfalls weiteren α,β-ungesättigten Verbindungen, wobei die Dicarbonsäureanhydrideinheiten zu einem hohen Anteil als Imideinheiten vorliegen und in geringerem Anteil als Amid/Ammoniumsalzeinheiten.

Copolymers or terpolymers based on α, β-unsaturated compounds and maleic acid are preferably used as the polymeric polar nitrogen-containing compounds. For example, the following are suitable:

The reaction products of alternating copolymers based on α, β-unsaturated compounds and maleic anhydride with primary monoalkylamines and aliphatic alcohols known from EP-A-0 154 177;

the reaction products of copolymers based on maleic anhydride and α, β-unsaturated compounds such as styrene with dialkylamines known from EP-A-0 436 151;

the copolymers based on aliphatic olefins and maleic anhydride disclosed in EP-A-0 283 293, the copolymer having both ester and amide groups, each of which contains an alkyl group at least 10 carbon atoms;

the reaction products of copolymers based on maleic anhydride and α, β-unsaturated compounds such as styrene with dialkylamines known from EP-A-0 436 151;

the terpolymers described in EP-A-0 606 055 based on α, β-unsaturated dicarboxylic acid anhydrides, α, β-unsaturated compounds and polyoxyalkylene ethers of lower, unsaturated alcohols;

the copolymers known from EP-A-0 688 796 based on α, β-unsaturated olefins having at least 3 C atoms and α, β-unsaturated dicarboxylic acid anhydrides, the dicarboxylic acid anhydride units being converted by polymer-analogous reaction with polyetheramines or alkanolamines in imide or amide - and ammonium units were transferred;

the statistical copolymers and terpolymers based on ethylene, α, β-unsaturated dicarboxylic acid anhydrides and optionally further α, β-unsaturated compounds described in the unpublished German patent application with the file number 196 45 603.7, the dicarboxylic acid anhydride units to a large extent as imide units are present and in a lower proportion than amide / ammonium salt units.

The mixtures according to the invention are mineral oils or mineral oil distillates in Form of concentrates added. These concentrates preferably contain 1 to 70, in particular 5 to 60 wt .-% of vinyl ester copolymers and Paraffin dispersants in a ratio of 1:10 to 10: 1, in particular in a ratio of 1: 5 to 5: 1 and 1 to 60 wt .-% in particular 5 to 50 wt .-% of the invention Solvent. The rest to 100% can be aliphatic, aromatic solvents as well as alkylphenol resins, alcohols, aldehydes and / or acetals. Through the Mixtures according to the invention improved in their rheological properties Mineral oils or mineral oil distillates contain 0.001 to 2, preferably 0.005 to 0.5% by weight of the mixtures, based on the distillate.

With the same result of optimizing the effectiveness as a flow improver for certain substrates, the mixtures according to the invention can also be used together with one or more oil-soluble co-additives, which in themselves improve the cold flow properties of crude oils, lubricating oils or fuel oils, such as comb polymers , Comb polymers are polymers in which hydrocarbon radicals having at least 8, in particular at least 10, carbon atoms are bonded to a polymer backbone. They are preferably homopolymers whose alkyl side chains contain at least 8 and in particular at least 10 carbon atoms. In copolymers, at least 20%, preferably at least 30%, of the monomers have side chains (cf. Comb-like Polymers - Structure and Properties; NA Platé and VP Shibaev, J. Polym. Sci. Macromolecular Revs. 1974, 8, 117 ff). Examples of suitable comb polymers are e.g. B. fumarate / vinyl acetate copolymers (cf. EP-A-0 153 176), copolymers of a C ₆ -C ₂₄ -α-olefin and an NC ₆ - to C ₂₂ -alkylmaleimide (cf. EP-A-0 320 766), also esterified olefin / maleic anhydride copolymers, polymers and copolymers of α-olefins and esterified copolymers of styrene and maleic anhydride.

The mixing ratio (in parts by weight) of the mixtures according to the invention with comb polymers is 1:10 to 20: 1, preferably 1: 1 to 10: 1.

The mixtures according to the invention are suitable for the cold flow properties of to improve animal, vegetable or mineral oils. You are for that Particularly suitable for use with middle distillates. As middle distillates One particularly refers to those mineral oils which are obtained by distilling crude oil be obtained and boiling in the range of 120 to 450 ° C, for example Kerosene, jet fuel, diesel and heating oil. The concentrates clearly show one improved storage stability, especially at low temperatures.

The new mixtures can be used alone or together with others Additives are used, for example with dewaxing aids, Corrosion inhibitors, antioxidants, lubricity additives or sludge inhibitors. These additives can be added to the oil together with those of the invention Mixing or done separately.

Examples

A) ethylene-vinyl acetate copolymer with 31 wt .-% vinyl acetate and one 140 ° C measured melt viscosity of 160 mPas, 58 wt .-% in Kerosene.

B) Ethylene-vinyl acetate-versatic acid vinyl ester terpolymer with 31% by weight Vinyl acetate, 4% by weight of versatic acid vinyl ester and one at 140 ° C measured melt viscosity of 180 mPas.

C) reaction product of a terpolymer of C _14/16 α-olefin, maleic anhydride and allyl polyglycol with 2 equivalents of ditallow fatty amine, 50% by weight in solvent naphtha (according to EP-A-0 606 055).

D) Nonylphenol-formaldehyde resin according to DE-A-31 42 955, produced by acid-catalyzed condensation of p-nonylphenol and formaldehyde, 50% in solvent naphtha.

E) Mixture of C + D in the ratio 1: 1

F) amide ammonium salt of a spirobislactone according to EP-A-0 413 279, 50% by weight in solvent naphtha.

MS) Solvent mixture consisting of the following main components: Di-2-ethylhexyl 20% 2-ethylhexyl acid-2-ethylhexyl 14% C ₁₆ lactones 17% 2-ethylhexanediol- (1,3) glycol mono-n-butyrate 10% 2-Ethylhexylbutyrat 5% 2-ethylhexanol 5% C ₄ to C ₈ acetals 10% Ether / ester ≥C ₂₀ 19%

The active ingredients listed above are homogenized in accordance with the amounts given in Tables 1 and 2 at 80 ° C. with stirring. The stability of the solutions is then assessed visually after storage for 3 days at room temperature or at 60 ° C. Ether and ester as solubilizers. All figures in% by weight. A B C F e solubilizers 23 ° C 60 ° C 50 50 - (Comparison) 2-phase 2-phase 50 50 - (Comparison) 2-phase 2-phase 50 50 - (Comparison) 2-phase 2-phase 67 33 - (Comparison) 2-phase 2-phase 40 40 20% kerosene (comparison) 2-phase cloudy 40 40 20% kerosene (comparison) 2-phase clear 40 40 20% solvent naphtha (comparison) 2-phase cloudy 40 40 20% solvent naphtha (comparison) 2-phase cloudy 60 30 10% MS cloudy, cloudy, homogeneously homogeneously 40 40 20% MS cloudy, clear, homogeneously homogeneously 40 40 20% MS cloudy, clear, homogeneously homogeneously 53 27 20% MS cloudy, clear, homogeneously homogeneously 40 40 20% dihexyl ether cloudy, clear, 50 50 -(Comparison) 2-phase 2-phase homogeneously homogeneously 40 40 20% dihexyl ether cloudy, clear, homogeneously homogeneously 40 40 20% dihexyl ether cloudy, clear, homogeneously homogeneously 53 27 20% dihexyl ether cloudy, clear, homogeneously homogeneously 40 40 20% adipic acid di (2-EH ester) cloudy, clear, homogeneously homogeneously 40 40 20% adipic acid di (2-EH ester) cloudy, clear, homogeneously homogeneously 40 40 20% adipic acid di (2-EH ester) cloudy, clear, homogeneously homogeneously 53 27 20% adipic acid di (2-EH ester) cloudy, clear, homogeneously homogeneously 40 40 20% ethyl hexanoate cloudy, clear, homogeneously homogeneously 53 27 20% ethyl octanoate cloudy, clear, homogeneously homogeneously 25 50 25% MS clear, clear, homogeneously homogeneously 34 33 33% MS cloudy, clear, homogeneously homogeneously 25 50 25% dihexyl ether clear, clear, homogeneously homogeneously 34 33 33% dihexyl ether cloudy, clear, homogeneously homogeneously 25 50 25% adipic acid di (2-EH ester) cloudy, clear, homogeneously homogeneously 34 33 33% adipic acid di (2-EH ester) cloudy, cloudy, homogeneously homogeneously 53 27 20% oleic acid eicosyl ester cloudy, clear, homogeneously homogeneously 53 27 20% 2-ethylhexyl stearate cloudy, clear, homogeneously homogeneously 50 50 - (Comparison) 2-phase 2-phase 53 27 20% 2-ethylhexyl stearate cloudy, clear, homogeneously homogeneously 53 27 20% 2-ethylhexyl stearate cloudy, clear, homogeneously homogeneously

When heated again, the mixtures according to the invention remain homogeneous.

List of trade names used

Solvent Naphtha ®Shellsol AB ®Solvesso 150 aromatic solvent mixtures with boiling range 180 to 210 ° C ®Solvesso 200 aromatic solvent mixture with boiling range 230 to 287 ° C ®Exxsol Dearomatized solvents in various boiling ranges, for example ®Exxsol D60: 187 to 215 ° C ®ISOPAR (Exxon) isoparaffinic solvent mixtures in various boiling ranges, for example ®ISOPAR L: 190 to 210 ° C ®Shellsol D mainly aliphatic solvent mixtures in different boiling ranges

Claims (8)

1. An additive for improving the flow properties of paraffin-containing mineral oils and mineral oil distillates, comprising a mixture of at least one ethylene/vinyl ester copolymer or terpolymer and at least one nitrogen-containing paraffin dispersant which is a polar, low-molecular-weight or polymeric oil-soluble compound which contains one or more ester, amide and/or imide groups substituted by at least one C₈-C₂₆-alkyl chain and/or carries one or more ammonium groups derived from amines having one or two C_8-C₂₆-alkyl groups, wherein said mixture contains ethers and/or esters as a solubilizer, where

   a) the ethers conform to the formula 1 R - O - R' in which R is a linear or branched alkyl or alkenyl group having 4 to 30 carbon atoms, and R' is a linear or branched alkyl or alkenyl group having 1 to 30 carbon atoms,

   b) the esters are derived from monobasic or polybasic carboxylic acids having linear or branched alkyl or alkenyl groups having 5 to 22 carbon atoms (acid radical) and from monohydric or polyhydric alcohols having linear or branched alkyl or alkenyl groups having 2 to 22 carbon atoms (alcohol radical), or

   c) the ethers and/or esters are cyclic, with R and R' or the acid and alcohol radicals forming a ring having 8 to 22 ring members.
2. An additive as claimed in claim 1, wherein the radicals R have from 5 to 22 carbon atoms and the radicals R' have from 2 to 22 carbon atoms.
3. An additive as claimed in claim 1 and/or 2, wherein the solubilizer is MS, MS having the following composition: Constituent Concentration range (% by wt.) Di-2-ethylhexyl ether 10 - 25 2-Ethylhexyl 2-ethylhexanoate 10 - 25 C₁₆ lactones 4 - 20 2-Ethylhexyl butyrate 3 - 10 2-Ethylhexane-1,3-diol mono-n-butyrate 5 - 15 2-Ethylhexanol 4 - 10 C₄- to C₈-acetals 2 - 10 2-Ethylhexane-1,3-diol 2 - 5 Ethers and esters ≥ C₂₀ 0 - 20.
4. An additive as claimed in one or more of claims 1 to 3, which additionally contains up to 10% by weight of alcohols and/or up to 30% by weight of alkylphenol-aldehyde resins.
5. An additive as claimed in one or more of claims 1 to 4, which contains at least one copolymer of ethylene and one or more vinyl esters.
6. An additive as claimed in one or more of claims 1 to 5, which contains a terpolymer which, in addition to from 65 to 94 mol% of structural units derived from ethylene and from 5 to 35 mol% of structural units derived from vinyl acetate, also contains from 1 to 25 mol% of structural units of the formula (2)

   

   in which R³ is saturated, branched C_6-C_16-alkyl containing a tertiary carbon atom.
7. A process for improving the flow properties of mineral oils and mineral oil distillates, which comprises adding additives as claimed in one or more of claims 1 to 6.
8. A mineral oil and mineral oil distillate containing additives as claimed in one or more of claims 1 to 6.