WO2016030341A1 - Method for the tertiary recovery of oil using hydophobically associating copolymers with improved injectivity - Google Patents

Abstract

The invention relates to a method for recovering oil in which an aqueous formulation that comprises at least one water-soluble hydrophobically associating copolymer and at least one surfactant is forced through at least one injection well into an oil deposit and crude oil is extracted from the deposit at least through a production well. The invention also relates to an aqueous solution and to a method for the use in the tertiary recovery of oil.

Description

 Process for tertiary mineral oil production using hydrophobically associating copolymers with improved injectivity

description

The present invention relates to a process for the extraction of crude oil, in which an aqueous formulation comprising at least one water-soluble, hydrophobically associating copolymer and at least one surfactant is injected through at least one injection well into a crude oil reservoir and crude oil is withdrawn from the reservoir through at least one production well. Furthermore, the invention relates to an aqueous formulation and its use in tertiary mineral oil production.

In natural oil deposits, petroleum is present in the cavities of porous reservoirs, which are closed to the earth's surface of impermeable cover layers. The cavities may be very fine cavities, capillaries, pores or the like. Fine pore necks, for example, have a diameter of only about 1 μηη. In addition to oil, including natural gas, a deposit also contains more or less saline water. In oil production, a distinction is made between primary, secondary and tertiary production.

In primary production, after drilling the deposit, petroleum automatically streams through the borehole due to the inherent pressure of the deposit. The autogenous pressure can be caused for example by existing in the deposit gases such as methane, ethane or propane. The autogenous pressure of the deposit, however, generally decreases relatively quickly when crude oil is withdrawn, so that by means of the primary production, depending on the type of deposit, only about 5 to 10% of the amount of crude oil present in the deposit can usually be extracted. After that, the autogenous pressure is no longer sufficient to extract oil.

After the primary promotion therefore usually the secondary promotion is used. In secondary production, additional wells will be drilled into the oil-bearing formation in addition to the wells that serve to extract the oil, known as production wells. Through these so-called injection wells, water is injected into the reservoir (the so-called "water flooding") to maintain or increase the pressure, and the injection of water causes the oil to slowly move from the injection well into the production well through the cavities in the formation However, this only works as long as the cavities are completely filled with oil and the viscous oil is pushed through the water, and as soon as the thin water breaks through cavities, it flows on the path of least resistance, So through the channel formed and no longer pushes the oil in front of him., By primary and secondary promotion therefore only about 30 to 35% of the amount of oil in the deposit to promote. Following the measures of secondary oil production, tertiary oil recovery measures, also known as Enhanced Oil Recovery (EOR), will be used to further increase oil yield, including certain chemicals such as surfactants and / or polymers An overview of tertiary oil production using chemicals can be found, for example, in the article by DG Kessel, Journal of Petroleum Science and Engineering, 2 (1989) 81-101.

In polymer flooding, an aqueous solution of a thickening polymer is injected into the oil reservoir through the injection wells, the viscosity of the aqueous polymer solution being adjusted to the viscosity of the crude oil Injecting the polymer solution, as in the case of flooding, presses the petroleum through the cavities in the formation from the injection well towards the production well, and the petroleum is pumped through the production well, but with the polymer formulation having about the same viscosity as the petroleum reduces the risk of the polymer formulation breaking through with no effect on production drilling, and thus the mobilization of the petroleum is much smoother than with the use of low viscosity water, so additional oil can be mobilized in the formation. Details of polymer flooding and polymers suitable therefor are disclosed, for example, in "Petroleum, Enhanced Oil Recovery, Kirk-Othmer, Encyclopedia of Chemical Technology, Online Edition, John Wiley & Sons, 2010".

For polymer flooding a variety of different, thickening acting polymers have been proposed, in particular high molecular weight polyacrylamide, copolymers of acrylamide and other comonomers such as vinyl sulfonic acid or acrylic acid. In particular, polyacrylamide may be partially hydrolyzed polyacrylamide in which a portion of the acrylamide units is hydrolyzed to acrylic acid. Furthermore, it is also possible to use naturally occurring polymers, for example xanthan or polyglycosylglucan, as described, for example, in US Pat. No. 6,392,596 B1 or CA 832,277.

Furthermore, it is known to use hydrophobically associating copolymers for polymer flooding. By this the skilled person means water-soluble polymers which have side or terminal hydrophobic groups, such as longer alkyl chains. In aqueous medium, such hydrophobic groups may associate with themselves or with other hydrophobic group-containing substances. As a result, an associative network is formed, through which the medium is thickened. Details of the use of hydrophobically associating copolymers for tertiary petroleum production are reviewed, for example, in the review by Taylor, KC and Nasr-El-Din, HA in J. Petr. Be. Closely. 1998, 19, 265-280. WO 2010/133527 discloses water-soluble, hydrophobically associating copolymers. The copolymers described include hydrophilic, monoethylenically unsaturated monomers such as, for example, acrylamide and also monoethylenically unsaturated hydrophobically associating monomers and can be used in the field of construction chemistry and tertiary mineral oil extraction for the purposes of the invention. aqueous phases. The copolymers can be formulated alone or together with surfactants to form a thickening system.

WO201 1/015520 A1 discloses a process for preparing hydrophobically associating copolymers by polymerizing water-soluble, monoethylenically unsaturated surface-active monomers and monoethylenically unsaturated hydrophilic monomers in the presence of non-polymerizable surfactants and the use of such copolymers for polymer flooding. WO 2012/069477 A1 describes a process for tertiary mineral oil production using hydrophobically associating copolymers which contain 0.1 to 15% by weight of at least one monoethylenically unsaturated, hydrophobically associating monomer (a) and 85 to 99.9% by weight of at least two , thereof various monoethylenically unsaturated hydrophilic monomers (b). The monomers (b) are at least one neutral, mono ethylenically unsaturated, hydrophilic monomer (b1) and at least one anionic, monoethylenically unsaturated, hydrophilic monomer (b2). The temperature in the oil reservoir is 35 to 120 ° C.

WO 2012/069438 describes a process for the oil claim using an aqueous formulation. This contains a water-soluble, hydrophobically associating copolymer and 0.005 to 1 wt .-% of a surfactant, which serves to increase the viscosity of the formulation.

EP 2 457 973 A1 relates to the use of a water-soluble, hydrophobically-associating copolymer as an additive in the development, exploitation and completion of underground oil and gas deposits. In the synthesis of the copolymer, a non-polymerizable surface-active compound is used prior to the initiation of the polymerization reaction. US 4,814,096 describes a process for tertiary mineral oil production using a hydrophobically associative mobility control composition. This comprises a hydrophilic / hydrophobic polymer having hydrophobic moieties and a water-dispersible surfactant having hydrophobic groups which can associate with the hydrophobic moieties of the polymer.

For polymer flooding, an aqueous, viscous polymer formulation is injected into a bore drilled in the petroleum formation. This well is also called "injection well" and is usually lined with cemented steel tubes that are perforated in the area of petroleum formation and thus allow the polymer formulation to exit the injection well into the petroleum formation.

Naturally, upon entering the petroleum formation, the aqueous polymer formulation must first pass through the volume element immediately around the injection well and spreads from there further in the petroleum formation. Accordingly, the flow rate of the aqueous polymer formulation is greatest at entry into the formation and decreases with increasing distance from the injection well. Since a petroleum formation is a porous material and the formulation must flow through the pores, very high shear forces act on the aqueous polymer formulation as it enters the formation. The greater the distance from the injection site, the lower the flow rate, and finally, the polymer solution flows at a slow rate through the formation towards the production well. Here, the polymer is exposed to only low shear rates.

An ideal polymer should therefore have an extremely shear thinning behavior. This means that the viscosity decreases as the shear increases, that is, when injecting the polymer solution, the viscosity should be low in order to quickly bring any amount of polymer into the formation. Once the formulation is in the formation, then high viscosity should be given to achieve optimal mobility reduction.

However, most of the polymers used hitherto, in particular hydrophobically associating copolymers, do not exhibit this ideal behavior.

The object of the invention was to provide an improved process for polymer flooding, in particular for fine-pored petroleum formations, in which the hydrophobically associating copolymer can be injected particularly well into the formation, but in the formation again a sufficiently high viscosity is achieved.

Accordingly, a process has been found in which an aqueous formulation is injected through at least one injection well into a crude oil deposit and the deposit is withdrawn through at least one production well crude oil, characterized in that the aqueous formulation

a) 500 to 5000 ppm of at least one water-soluble, hydrophobically associating copolymer (A), obtainable from the reaction of a1) from 0.1 to 15.0% by weight of at least one monoethylenically unsaturated hydrophobically associating monomer (A1), where at least one monoethylenically unsaturated hydrophobically associating monomer (A1) is a monomer according to one of the formulas selected from

H ₂ C = C (R ¹ ) -R ² -O- (CH ₂ -CH (R ³ ) -O) k- (CH ₂ -CH (R ⁴ ) -O) i R ⁵ (I), H ₂ C = C (R ¹ ) -O- (CH ₂ -CH ₂ (R ³ ) -O) k R ⁶ (II),

wobei die Einheiten -(CH₂-CH(R³)-0)_k und -(CH₂-CH(R⁴)-0)i sowie gegebenenfalls - [(CH2-CH(R⁴)-0)h-(CH2-CH₂-0)i] in Blockstruktur in der in Formel (I) beziehungsweiseH ₂ C = C (R ¹ ) - (C = O) -O- (CH ₂ -CH (R ³ ) -O) k R ⁶ (III), and H ₂ C = C (R ¹ ) -R ² -O- (CH ² -CH (R ³ ) -O) k- (CH ² -CH (R ⁴ ) -O) i - [(CH 2 -CH (R ⁴ ) -0) h (CH ₂ -CH ₂ -

wherein the moieties - (CH ₂ -CH (R ³⁾ -0) _k and - (CH ₂ -CH (R ⁴⁾ -0) i and, optionally, - [(CH 2 CH (R ⁴⁾ -0) h- ( CH ₂ -CH ₂ -O) i] in block structure in the formula (I) or

Formula (IV) are arranged, and the radicals and indices have the following meaning:

 k: is a number from 10 to 50;

 I: is a number from 5 to 25;

 h: is a number from 0 to 2;

 i: is a number from 1 to 15;

R ¹ : is H or methyl;

R ² : is a single bond or a divalent linking group selected from the group consisting of - (CnFbn) -, -O- (Ο _η Ή2η) - and

-C (O) -O- (Cn "H2n") - where n, n 'and n "are each a natural number from 1 to 6;

each R ³ : is independently H, methyl or ethyl, provided that at least 50 mole% of R ³ is H;

each R ^4: is independently a hydrocarbon radical of at least 2

Carbon atoms or an ether group of the general formula --CH 2 -OR ^{4 '} , wherein R ^{4' is} a hydrocarbon radical having at least 2 carbon atoms, with the proviso that R ^{4 is} a hydrocarbon radical having at least 3 carbon atoms when R ^{3 is} ethyl;

R ⁵ : is H or a hydrocarbon radical having 1 to 30 carbon atoms;

R ⁶ : is an aliphatic and / or aromatic, linear or branched

Hydrocarbon radical having 8 to 40 carbon atoms; and a2) from 85.0 to 99.9% by weight of at least one hydrophilic monomer (A2) other than monomer (A1), at least one of the monomers (A2) being a neutral, monoethylenically unsaturated hydrophilic monomer (A2a) selected from the group consisting of (meth) acrylamide, N-methyl (meth) acrylamide, N, N'-dimethyl (meth) acrylamide and N-methylol (meth) acrylamide; wherein the amounts of the monomers (A1) and (A2) are each based on the total amount of all monomers used in the reaction, and wherein the copolymer (A) has a weight-average molecular weight M _w of 1 x 10 ⁶ to 30 x 10 ⁶ g / mol having; such as b) at least 0.5 and less than 50.0 ppm of at least one surfactant (B), wherein the at least one surfactant (B) is selected from the group consisting of nonionic surfactants (B1) having an HLB value of more than 1 , anionic surfactants (B2), cationic surfactants (B3) and zwitterionic surfactants (B4), wherein the quantities of the copolymer (A) and of the surfactant (B) in each case based on the sum of all components of the aqueous formulation contains, and wherein the weight ratio of the at least one copolymer (A) to the at least one surfactant (B) is in the range of 10: 1 to 1000: 1

A further aspect of the present invention relates to an aqueous formulation comprising at least one water-soluble, hydrophobically associating copolymer (A) and at least one surfactant (B). A further aspect of the present invention relates to the use of the aqueous formulation according to the invention in the development, exploitation and completion of underground oil and natural gas deposits, in particular in tertiary mineral oil production.

It has now surprisingly been found that by adding small amounts of at least one surfactant (B), the viscosity of the aqueous formulation comprising at least one water-soluble, hydrophobically associating copolymer (A) can be lowered. Furthermore, it has been found that the surfactant (B) can be adsorbed on the rock surfaces in the petroleum deposit, thereby again increasing the viscosity of the formulation in the formation. Hydrophobic Associating Copolymers (A)

 For the process according to the invention for crude oil production, an aqueous formulation comprising at least one water-soluble, hydrophobically associating copolymer (A) and at least one surfactant (B) is used and injected through at least one injection well into a crude oil deposit.

The term "water-soluble hydrophobically associating copolymer" is known in principle to the person skilled in the art.

This is a water-soluble copolymer which, in addition to hydrophilic moieties which ensure adequate water solubility, has pendant or terminal hydrophobic groups. In aqueous solution, the hydrophobic groups of the polymer can associate with themselves or with other hydrophobic group-containing materials due to intermolecular forces. This results in a polymeric network linked by intermolecular forces, which thickens the aqueous medium.

Ideally, the copolymers used according to the invention should be miscible with water or soluble in water in any desired ratio. According to the invention, it is sufficient if the copolymers at least at the desired use concentration and the desired pH are water-soluble. As a rule, the solubility of the copolymer in water at room temperature under the conditions of use should be at least 25 g / l in the neutral pH range. According to the invention, the water-soluble, hydrophobically associating copolymer (A) is obtainable from the reaction of from 0.1 to 15.0% by weight of at least one monoethylenically unsaturated, hydrophobically associating monomer (A1) and from 85.0 to 99.9% by weight. at least one hydrophilic monomer (A2) other than (A1), wherein at least one of the monomers (A2) is a neutral, monoethylenically unsaturated hydrophilic monomer (A2a) selected from the group consisting of (meth) acrylamide, N-methyl (meth) acrylamide, N, N'-dimethyl (meth) acrylamide and N-methylol (meth) acrylamide.

Monomers (A1)

 The water-soluble, hydrophobically associating copolymer (A) used is obtainable from the reaction of at least one monoethylenically unsaturated monomer (A1) and at least one hydrophilic monomer (A2) other than monomer (A1), where at least one of the monomers (A2) is a neutral, monoethylenically unsaturated hydrophilic monomer (A2a) selected from the group consisting of (meth) acrylamide, N-methyl (meth) acrylamide, N, N'-dimethyl (meth) acrylamide and N-methylol (meth) acrylamide ,

Monomer (A1) imparts hydrophobic associating properties to the copolymer and will therefore be referred to hereinafter as the "hydrophobically associating monomer".

The at least one hydrophobically associating monomer (A1) comprises, in addition to the ethylenically unsaturated group, a hydrophobic group which, after the polymerization, is responsible for the hydrophobic association of the copolymer formed. Preferably, it further comprises hydrophilic moieties that impart some water solubility to the monomer.

Monomers (A1) The invention relates to a process, wherein the at least one monoethylenically unsaturated hydrophobically associating monomer (A1) is a monomer according to one of the formulas selected from

H ₂ C = C (R ¹ ) -R ² -O- (CH ₂ -CH (R ³ ) -O) k- (CH ₂ -CH (R ⁴ ) -O) i R ⁵ (I),

H ₂ C = C (R ¹ ) -O- (CH ₂ -CH ₂ (R ³ ) -O) kR ⁶ (II),

H ₂ C = C (R ¹ ) - (C = O) -O- (CH ₂ -CH (R ³ ) -O) k R ⁶ (III), and

H ₂ C = C (R ¹ ) -R ² -O- (CH ₂ -CH (R ³ ) -O) _k - (CH ₂ -CH (R ⁴ ) -O) i - [(CH ₂ -CH ( R ⁴ ) -O) h (CH ₂ -CH ₂ -O) i] -R ⁵ (IV) wherein the moieties - (CH ₂ -CH (R ³⁾ -0) _k and - (CH ₂ -CH (R ⁴⁾ -0) i and, optionally, - [(CH 2 CH (R ⁴⁾ -0) h- ( CH ₂ -CH ₂ -O) i] are arranged in block structure in the order shown in formula (I) or formula (IV), and the radicals and indices have the following meaning:

 k: is a number from 10 to 50;

 I: is a number from 5 to 25;

 h: is a number from 0 to 2;

 i: is a number from 1 to 15;

R ¹ : is H or methyl;

R ² : is a single bond or a divalent linking group selected from the group consisting of - (CnFbn) -, -O- (Cn F n) - and -C (O) -O- (Cn "H2n") - wherein n, n 'and n "are each a natural number of 1 to 6;

each R ³ : is independently H, methyl or ethyl, provided that at least 50 mole% of R ³ is H;

each R ^4: is independently a hydrocarbon radical of at least 2

Carbon atoms or an ether group of the general formula --CH 2 -OR ^{4 '} , wherein R ^{4' is} a hydrocarbon radical having at least 2 carbon atoms, with the proviso that R ^{4 is} a hydrocarbon radical having at least 3 carbon atoms when R ^{3 is} ethyl;

R ⁵ : is H or a hydrocarbon radical having 1 to 30 carbon atoms;

R ⁶ : is an aliphatic and / or aromatic, linear or branched

 Hydrocarbon radical having 8 to 40 carbon atoms.

Monomers (A1) of the formula (I)

In the monomers (A1) of the formula (I), an ethylenic group H2C = C (R ¹ ) - via a divalent, linking group -R ² -O- with a polyalkyleneoxy radical having a block structure - (CH ₂ -CH (R ³ ) -0) _k - (CH ₂ -CH (R) -O) i R ⁵ where the blocks are - (CH ₂ -CH (R ³ ) -O) _k and - (CH ₂ -CH (R ⁴ ) -O) i are arranged in the order shown in formula (I). The polyalkyleneoxy group has either a terminal OH group or a terminal ether group OR ⁵ . In the above formulas, R ^{1 is} H or methyl.

R ² is a single bond or a divalent linking group selected from the group consisting of - (CnF n) -, -O- (Ο _η Ή2η) - and -C (O) -O- (C _n H2n ") In said formulas, n, n 'and n "are each a natural number from 1 to 6. In other words, the linking group is aliphatic hydrocarbon groups having 1 to 6 carbon atoms, which are either directly, through a Ether group -O- or via an ester group -C (0) -0- with the ethylenic group H2C = C (R ¹ ) - are linked. The linking group may be a straight-chain or, if n, n 'or n', a natural number from 3 to 6, also branched aliphatic hydrocarbons act. The groups - (CnFn) -, - (Cn-n) - and - (Cn -n) - are preferably linear aliphatic hydrocarbon groups. Preferably, the group - (CnF n) - is a group selected from -CH 2 - - CH 2 -CH 2 - and -CH 2 -CH 2 -CH 2 -, more preferably a methylene group is -CH 2 -.

Preferably, the group -O- (Ο _η Ή2η) - is a group selected from -O-CH 2 -CH 2 -, -O-CH 2 -CH 2 -CH 2 - and -O-CH 2 -CH 2 -CH 2 -CH 2 - , particularly preferred is -O-

The group -C (O) -O- (C _n H 2n ") - is preferably a group selected from -C (O) -O-CH ₂ -CH ₂ -, -C (O) O-CH (CH ₃ ) -CH ₂ -, -C (O) O-CH ₂ -CH (CH ₃ ) -, -C (O) O-CH ₂ -CH ₂ - CH ₂ -CH ₂ - and -C (O) O -CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ -, especially preferred are -C (O) -O-CH ₂ -CH ₂ - and -C (O) O-CH ₂ -CH ₂ -CH ₂ -CI-12-and all particularly preferred is -C (O) -O-

Particularly preferably, the group R ² is a group - (CnF n) - or -O- (Cn'H2n) -, more preferably a group -0- (Ο _η Ή2η) -, ie monomers (A1 ) based on vinyl ethers.

With particular preference, R ² is a group selected from

-CH 2 - or -O-CH 2 -CH 2 -CH 2 -CH 2 -, most preferably -O-CH 2 -CH 2 -CH 2 -CH 2 -. In a preferred embodiment, R ² is a group -O- (Ο _η Ή2η) -, where n 'is a natural number from 2 to 4, preferably 4.

The monomers (A1) according to the formula (I) furthermore have a polyalkyleneoxy radical which consists of the units - (CH ₂ -CH (R ³ ) -O) _k and - (CH ₂ -CH (R ⁴ ) -O) i wherein the units are arranged in block structure in the order shown in formula (I). The transition between the two blocks can be abrupt or continuous.

In a continuous transition, there is still a transition zone between the two blocks, which comprises monomers of both blocks. If one sets the block boundary to the center of the transition zone, can, accordingly, the first block - (CH2-CH (R ³⁾ -0) k small amounts of units -CH ₂ -CH (R ⁴⁾ -0- and the second block - (CH ₂ -CH (R ⁴ ) -O) i- small amounts of units -CH ₂ -CH (R ³ ) -O- have, but these units are not statistically distributed over the block, but arranged in said transition zone are.

In the block - (CH 2 -CH (R ³ ) -O) k, the radicals R ³ independently of one another are H, methyl or ethyl, preferably H or methyl, with the proviso that at least 50 mol% of the radicals R ³ is about H Preferably, at least 75 mol% of the radicals R ³ H, particularly preferably at least 90 mol% and very particularly preferably exclusively H. The block is thus a polyethyleneoxy block, which may optionally still contain certain proportions of propyleneoxy and / or butyleneoxy units, is preferred a pure polyethyleneoxy block.

The number of alkylenoxy units k is a number from 10 to 50, preferably 12 to 40, more preferably 15 to 35, most preferably 20 to 30 and for example about 22 to 25. In the second block - (CH2 -CH (R ⁴ ) -O) i- the radicals R ^{4 are} independently hydrocarbon radicals having at least 2 carbon atoms, preferably at least 3, more preferably 3 to 10, most preferably 3 to 8 carbon atoms and in particular 3 or 4 carbon atoms. It may be an aliphatic and / or aromatic, linear or branched hydrocarbon radical. It is preferably an aliphatic hydrocarbon radical, further preferably an acyclic, saturated hydrocarbon radical.

According to the invention, R ⁴ is a hydrocarbon radical having at least 3 carbon atoms when R ^{3 is} ethyl. In other words, the units - (CH ₂ -CH (R ³ ) -O) - and - (CH ₂ -CH (R ⁴ ) -O) - are different in number from their carbon atoms.

Examples of suitable radicals R ⁴ include ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl or n-decyl and also phenyl. Examples of preferred radicals include n-propyl, n-butyl, n-pentyl and particularly preferred is an n-propyl radical.

The radicals R ⁴ may furthermore be ether groups of the general formula -CH 2 -O-R ^{4 '} , where R ^4' is an aliphatic and / or aromatic, linear or branched hydrocarbon radical having at least 2 carbon atoms, preferably at least 3 and more preferably 3 to 10 carbon atoms. Examples of radicals R ^{4 '} include n-propyl, n-butyl, n-pentyl, n-hexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or phenyl.

The block - (CH 2 -CH (R ⁴ ) -O) i- is therefore preferably a block which consists of alkyleneoxy units having at least 4 carbon atoms, preferably at least 5 carbon atoms, in particular 5 to 10 carbon atoms and / or glycidyl ethers having an ether group of at least 2, preferably at least 3 carbon atoms. Preferred radicals R ⁴ are the hydrocarbon radicals mentioned; the building blocks of the second terminal block are particularly preferably alkyleneoxy units comprising at least 5 carbon atoms, such as pentyleneoxy units or units of higher alkylene oxides. Most preferably, the second terminal block is a pentyleneoxy block. The number of alkyleneoxy units I is a number from 5 to 25, preferably 6 to 20, particularly preferably 8 to 18, very particularly preferably 10 to 15 and for example 12. It is clear to the person skilled in the art of the polyalkoxylates in that the definitions of k and I are the definition of a single monomer (A1) of the formula in each case. In the case of the presence of mixtures of several monomers (A1) of the formula (I) or formulations comprising a plurality of monomers (A1) of the general formula (I), the numbers k and I are average values over all molecules of the monomers, since in the alkoxylation of alcohol with alkylene oxides in each case a certain distribution of chain lengths is obtained.

The same applies with regard to the polyalkoxylates according to the formulas (II), (III), (IV), (V), (VI) and (VIII) which are listed below.

The radical R ⁵ is H or a, preferably aliphatic, hydrocarbon radical having 1 to 30 carbon atoms, preferably 1 to 10 carbon atoms and particularly preferably 1 to 5 carbon atoms. It is preferable that when R ⁵ is H, methyl or ethyl, more preferably H or methyl, and most preferably H.

In a preferred embodiment, the invention relates to a process wherein the radicals and indices in the formula (I) have the following meaning:

 k: is a number from 12 to 40;

 I: is a number from 6 to 20;

R ² : is a divalent linking group -O- (Ο _η Ή2η) -, where n 'is a natural number from 2 to 4;

each R ³ : is independently H or methyl, provided that at least 50 mole% of R ³ is H;

each R ⁴ : is independently a hydrocarbon radical having 3 to 8 carbon atoms;

R ⁵ : is independently H, methyl or ethyl.

In a further preferred embodiment, the invention relates to a process wherein the radicals and indices in the formula (I) have the following meaning:

 k: is a number from 15 to 35;

 I: is a number from 8 to 18;

R ² : is a divalent linking group -O- (Ο _η Ή2η) -, where n 'is 4;

R ³ : is H;

R ⁴ : is an n-propyl radical

R ⁵ is H. In the case of the monomers of the formula (I), therefore, a terminal, monoethylenic group is preferably linked to a block-structured polyalkyleneoxy group, first with a block having a hydrophilic polyethyleneoxy moiety, preferably consisting of polyethyleneoxy units, and this in turn with a second block terminal, hydrophobic block, which is more composed at least of butyleneoxy units, preferably at least pentyleneoxy units or units of higher alkylene oxides such as dodecylene oxide. The second block has a terminal -OR ⁵ group, in particular an OH group.

The terminal block - (CH 2 -CH (R ⁴ ) -O) i with the radicals R ⁴ is responsible for the hydrophobic association of the copolymers prepared using the monomers (A1). Verethern of the OH end group is an option that can be chosen by the skilled person depending on the desired properties of the copolymer. However, a terminal hydrocarbon group is not required for hydrophobic association, but hydrophobic association also works for a terminal OH group.

Preparation of Preferred Monomers (A1) of the Formula (I)

The preparation of the hydrophobically associating monomers (A1) of the formula (I) can be carried out by methods known in principle to those skilled in the art. To prepare the monomers (A1), in a preferred preparation process, suitable monoethylenically unsaturated alcohols (IX) are used, which are subsequently alkoxylated in a two-stage process, so that the abovementioned block structure is obtained. This gives monomers (A1) of formula (I) with R ⁵ = H. These can be optionally etherified in a further process step.

The type of ethylenically unsaturated alcohols (IX) to be used depends in particular on the group R ² .

If R ^{2 is} a single bond, one starts from alcohols (IX) of the general formula H ₂ C =C (R ¹ ) -O- (CH ₂ -CH (R ⁷ ) -O-) dH (IXa), where R ^{1 has} the meaning defined above, R ^{7 is} H and / or CH 3, preferably H and d is a number from 1 to 5, preferably 1 or 2. Examples of such alcohols include diethylene glycol vinyl ether H ₂ C = CH-O-CH ₂ -CH ₂ -O-CH ₂ -CH 2 -OH or dipropylene glycol vinyl ether H ₂ C = CH-O-CH 2 -CH (CH ₃ ) -O-CH 2 -CH (CH ₃ ) -OH , preferred is diethylene glycol vinyl ether.

(IXb) oder bereits Alkoxygruppen aufweisende Alkohole der Formel H₂C=C(R¹)-R²-0-(CH₂-CH(R⁷)-0)d-H (IXc) eingesetzt werden, wobei R⁷ und d die oben definierte Bedeutung haben, und R² jeweils aus der Gruppe bestehend aus -(C_nH₂n)-, -0-(Cn'H_2n')- und -C(0)-0-(C_n H₂n")- ausgewählt wird. For the preparation of monomers (A1) in which R ^{2 is} not a single bond, alcohols of the general formula

(IXb) or alcohols already having alkoxy groups of the formula H ₂ C =C (R ¹ ) -R ² -O- (CH ₂ -CH (R ⁷ ) -O) dH (IXc) where R ⁷ and d are the have defined above, and R ^{2 is in} each case selected from the group consisting of - (C _n H ₂ n) -, -O- (Cn'H _2n ') - and -C (0) -O- (C _n H ₂ n ") - is selected.

insbesondere H₂C=CH-(C_nH₂n)-OH oder Alko- holen der Formel H₂C=C(R¹)-0-(CH₂-CH(R⁷)-0)d-H aus. Beispiele bevorzugter Alkohole umfassen Allylalkohol H₂C=CH-CH₂-OH oder Isoprenol H₂C=C(CH₃)-CH₂-CH₂-OH. For the preparation of the monomers with linking group - (C _n H2n) - it is preferable to use alcohols of the formula

in particular H ₂ C =CH- (C _n H ₂ n) -OH or alkoxy get the formula H ₂ C = C (R ¹ ) -O- (CH ₂ -CH (R ⁷ ) -O) dH. Examples of preferred alcohols include allyl alcohol H ₂ C = CH-CH ₂ -OH or isoprenol H ₂ C = C (CH ₃ ) -CH ₂ -CH ₂ -OH.

To prepare the monomers having the linking group -O- (C _n H ₂ n ') - starting from vinyl ethers of the formula H ₂ C =C (R ¹ ) -O- (C _n ' H _2n ') -OH, preferably H ₂ C = CH-O- (C _n 'H _2n ') -OH from. Particular preference is given to using ω-hydroxybutylvinyl ether H ₂ C =CH-O-CH ₂ -CH ₂ -CH ₂ -CH ₂ -OH.

bevorzugt H₂C=C(R¹)-C(0)-0-(C_n"H_2n")-OH aus. Beispiele bevorzugter Hydroxyalkyl(meth)acrylate umfassen Hydroxyethyl(meth)acrylat H₂C=C(R¹)-C(0)-0-CH₂-CH₂-OH sowie Hydro- xybutyl(meth)acrylat H₂C=C(R¹)-C(0)-0-CH₂-CH₂-CH₂-CH₂-OH. Die genannten Ausgangsverbindungen werden alkoxyliert, und zwar in einem zweistufigen Pro- zess zunächst in einem ersten Schritt S1 mit Ethylenoxid, optional im Gemisch mit Proyplenoxid und/oder Butylenoxid und in einem zweiten Schritt S2 mit Alkylenoxiden der allgemeinen Formeln (Xa) beziehun sweise (Xb)

wobei R⁴ in den Formeln (Xa) und (Xb) die eingangs definierte Bedeutung haben. Die Durchführung einer Alkoxylierung einschließlich der Herstellung von Blockcopolymeren aus verschiedenen Alkylenoxiden ist dem Fachmann prinzipiell bekannt. Es ist dem Fachmann ebenfalls bekannt, dass man durch die Reaktionsbedingungen, insbesondere die Wahl des Katalysators, die Molekulargewichtsverteilung der Alkoxylate sowie die Orientierung von Alkylen- oxy-Einheiten in einer Polyetherkette beeinflussen kann. For the preparation of the monomers with linking group -C (O) -O- (C _n H _2n ) - one starts from hydroxyalkyl (meth) acrylates of the general formula

preferably H ₂ C = C (R ¹ ) -C (O) -O- (C _n "H _2n ") -OH from. Examples of preferred hydroxyalkyl (meth) acrylates include hydroxyethyl (meth) acrylate H ₂ C = C (R ¹ ) -C (O) -O-CH ₂ -CH ₂ -OH and hydroxybutyl (meth) acrylate H ₂ C = C (R ¹ ) -C (O) -O-CH ₂ -CH ₂ -CH ₂ -CH ₂ -OH. The stated starting compounds are alkoxylated, in a two-stage process first in a first step S1 with ethylene oxide, optionally in admixture with propylene oxide and / or butylene oxide and in a second step S2 with alkylene oxides of the general formulas (Xa) (Xb) )

wherein R ⁴ in the formulas (Xa) and (Xb) have the meaning defined above. The carrying out of an alkoxylation, including the preparation of block copolymers of various alkylene oxides, is known in principle to a person skilled in the art. It is also known to the person skilled in the art that the reaction conditions, in particular the choice of catalyst, can influence the molecular weight distribution of the alkoxylates and the orientation of alkyleneoxy units in a polyether chain.

The alkoxylates can be prepared, for example, by base-catalyzed alkoxylation. For this purpose, the alcohol used as starting material can be mixed in a pressure reactor with alkali metal hydroxides, preferably potassium hydroxide or with alkali metal such as sodium methoxide. By reduced pressure (for example, less than 100 mbar) and / or increasing the temperature (30 to 150 ° C), water still present in the mixture can be removed. The alcohol is then present as the corresponding alkoxide. Subsequently, it is inertized with inert gas (for example nitrogen) and in a first step S1 ethylene oxide, optionally mixed with propylene and / or butylene oxide at temperatures of 60 to 180 ° C, preferably 130 to 150 ° C added gradually. The addition is typically within 2 to 5 hours, without the invention being intended to be so limited. After completion of the addition, the reaction mixture is allowed to react appropriately, for example, for 0.5 to 1 hours. In a second step S2, subsequently alkylene oxides of the general formula (Xa) or (Xb) are metered in step by step. The reaction temperature in the second stage S2 can be maintained or changed. A reaction temperature which is around 10 to 25 ° C lower than in the first stage has proven to be suitable.

The alkoxylation can also be carried out by techniques which result in narrower molecular weight distributions than in the base-catalyzed synthesis. For this purpose, for example, double hydroxide clays as described in DE 43 25 237 A1 can be used as the catalyst. The alkoxylation can be carried out particularly preferably using double metal cyanide catalysts (DMC catalysts). Suitable DMC catalysts are disclosed, for example, in DE 102 43 361 A1, in particular sections [0029] to [0041], and the literature cited therein. For example, Zn-Co type catalysts can be used. To carry out the reaction, the alcohol used as the starting material may be added with the catalyst, the mixture dehydrated as described above and reacted with the alkylene oxides as described. Usually not more than 250 ppm of catalyst are used with respect to the mixture; The catalyst can remain in the product due to this small amount.

The alkoxylation can also be carried out acid-catalyzed. The acids may be Bronsted or Lewis acids. To carry out the reaction, the alcohol used as the starting material may be added with the catalyst, the mixture dehydrated as described above and reacted with the alkylene oxides as described. At the end of the reaction, the acidic catalyst can be neutralized by addition of a base, for example KOH (potassium hydroxide) or NaOH (sodium hydroxide) and filtered off as required. It will be clear to one skilled in the art of polyalkylene oxides that the orientation of the hydrocarbon radicals R ⁴ and optionally R ³ may depend on the conditions of the alkoxylation, for example on the catalyst chosen for the alkoxylation. The alkylene oxide groups can thus be incorporated into the monomer both in the orientation - (CH 2 -CH (R ⁴ ) -O) or in inverse orientation - (CH (R ⁴ ) -CH 2 -). The representation in formula (I) should therefore not be regarded as being restricted to a specific orientation of the groups R ³ or R ⁴ .

If the terminal OH group of the monomers (A1) of the formula (I) (that is to say R ⁵ = H) is to be etherified, this can be carried out with conventional alkylating agents known in principle, for example with dimethyl sulfate and diethyl sulfate. The etherification is preferably carried out with a compound of the formula R ⁵ -X ', where X' is a leaving group, preferably selected from the group consisting of Cl, Br, I, -O-SO 2 -CH 3 (mesylate), -O-SO 2-CF 3 (Triflate) or -O-SO 2 -OR ⁵ . The etherification is only an option that can be selected by the skilled person depending on the desired properties of the copolymer.

Particularly preferred preparation process for the monomers (A1) of the formula (I) In an advantageous embodiment, the monomers (A1) of the formula (I) can be prepared by means of the below-described, particularly preferred process.

In this case, step S1 is carried out with the addition of an alkaline catalyst K1 comprising KOMe (potassium methoxide) and / or NaOMe (sodium methoxide).

Step S2 is carried out with the addition of an alkaline catalyst K2, wherein the concentration of potassium ions in the reaction in step S2 less than or equal to 0.9 mol%, preferably less than 0.9 mol%, preferably in the range of 0.01 to 0 , 9 mol%, particularly preferably from 0.01 to 0.5 mol%, based on the alcohol used H ₂ C =C (R ¹ ) -R ² -O- (CH ₂ -CH (R ³ ) -O) _k -H (la) and wherein the reaction in step S2 at a temperature of less than or equal to 135 ° C, preferably of less than 135 ° C, more preferably of less than or equal to 130 ° C, for example from 120 ° C to 130 ° C is carried out, whereby the monomer (A1) of the formula (I) with R = H is obtained.

The preferred conditions mentioned below (for example pressure and / or temperature ranges) in the reactions in steps S1 and S2 mean that the respective step is carried out in whole or in part under the stated conditions. Preferably, step S1 first comprises the reaction of the monoethylenically unsaturated alcohol (IX) with the alkaline catalyst K1. Typically, the alcohol used as starting material (IX) is added in a pressure reactor with an alkaline catalyst K1. By reduced pressure of typically less than 100 mbar, preferably in the range of 30 to 100 mbar and / or increasing the temperature typically in the range of 30 to 150 ° C, water and / or low boilers still present in the mixture can be withdrawn. The alcohol is then present essentially as a corresponding alkoxide. Subsequently, the reaction mixture is typically treated with inert gas (e.g., nitrogen).

Preferably, step S1 comprises the addition of ethylene oxide and optionally small amounts of higher alkylene oxides to the mixture of alcohol (IX) and alkaline catalyst K1. After completion of the addition of the ethylene oxide and optionally further alkylene oxides, the reaction mixture is typically allowed to react. The addition including optional depressions (intermediate reduction of the pressure from, for example, 6 to 3 bar absolute) and including post-reaction typically takes place over a period of 2 to 36 hours, preferably from 5 to 24 hours, particularly preferably from 5 to 15 hours, more preferably from 5 to 10 h.

Step S1 is typically carried out at temperatures of 120 to 160 ° C, preferably from 130 to 150 ° C, more preferably from 140 to 150 ° C. In particular, step S1 comprises the addition of the ethylene oxide and optionally small amounts of further alkylene oxides to the mixture of alcohol (IX) and alkaline catalyst K1 at a temperature of 120 to 160 ° C, particularly preferably 140 to 150 ° C. The addition of the ethylene oxide and optionally small amounts of further alkylene oxides to the mixture of alcohol (IX) and alkaline catalyst K1 preferably takes place at a pressure in the range from 1 to 7 bar, preferably in the range from 1 to 6 bar. To meet the safety conditions, the addition in step S1 typically at a pressure in the range of 1 to 4 bar, preferably 1 to 3.9 bar, more preferably from 1 to 3.1 bar or in another embodiment of the invention from 3 to 6 bar. In particular, the addition of ethylene oxide and / or the post-reaction is carried out at the abovementioned pressures. Step S1 preferably comprises the addition of the ethylene oxide and optionally small amounts of further alkylene oxides to a mixture of alcohol A1 and alkaline catalyst K1 over a period of less than or equal to 36 h, preferably less than or equal to 32 h, more preferably over a period of from 2 to 32 h, in particular preferably over a period of 5 to 15 h, and at a pressure of less than or equal to 5 bar, preferably at 1 to 4 bar, in particular preferably 1 to 3.9 bar. In particular, the above period comprises the addition of ethylene oxide and / or the post-reaction.

In particular, the reaction of a monoethylenically unsaturated alcohol (IX) with ethylene oxide and optionally small amounts of further alkylene oxides with addition of an alkaline catalyst K1 comprising KOMe (potassium methoxide) and / or sodium methoxide (NaOMe) according to step S1 of the preferred process can be carried out in one or more ethoxylation steps.

Particularly preferred is a method as described above, wherein step S1 comprises the following substeps:

 Reaction of the monoethylenically unsaturated alcohol (IX) with the alkaline catalyst K1,

 Reaction of the mixture of alcohol (IX) and catalyst K1 with a portion of the ethylene oxide and optionally small amounts of further alkylene oxides, in particular 10 to 50 wt .-%, in particular 10 to 30 wt .-%, of the total amount of ethylene oxide and optionally small amounts of others alkylene oxides,

 an intermediate step comprising a quiescent phase and / or a pressure release, and the reaction with the remaining part of the ethylene oxide and optionally small amounts of further alkylene oxides.

Further preferred is a method as described above, wherein step S1 comprises the following substeps:

 Reaction of the monoethylenically unsaturated alcohol (IX) with the alkaline catalyst K1,

Reaction of the mixture of alcohol (IX) and catalyst K1 with a portion of the ethylene oxide and optionally small amounts of further alkylene oxides, in particular 50 to 98 wt .-%, in particular 80 to 98 wt .-%, of the total amount of ethylene oxide and optionally small amounts further alkylene oxides, a step for removing low boilers under pressure release to a pressure of less than 100 mbar, preferably 30 to 100 mbar and / or increasing the temperature typically in the range of 30 to 150 ° C,

 Reaction of the obtained ethoxylation product with the alkaline catalyst K1 and reaction of the remaining part of the ethylene oxide with the mixture of ethoxylation product and alkaline catalyst K1.

The alkaline catalyst K1 contains in particular 10 to 100 wt .-%, preferably 20 to 90 wt .-% KOMe and / or NaOMe. The catalyst K1 may contain, in addition to KOMe and / or NaOMe, further alkaline compounds and / or a solvent (in particular a C1 to C6 alcohol). For example, a further alkaline compound may be present selected from alkali metal hydroxides, alkaline earth metal hydroxides, C2 to C6 potassium alkoxides, C2 to C6 sodium alkoxides (preferably ethanolate), alkaline earth alkoxides (especially C1 to C6 alkoxides, preferably methanolate and / or ethanolate). In addition to KOMe and / or NaOMe, the catalyst K1 preferably contains at least one further alkaline compound selected from sodium hydroxide and potassium hydroxide.

In a further preferred embodiment, the alkaline catalyst K1 consists of KOMe or of a solution of KOMe in methanol (MeOH). Typically, a solution of 20 to 50% by weight KOMe in methanol (MeOH) can be used.

In a further preferred embodiment, the alkaline catalyst K1 consists of NaOMe or of a solution of NaOMe in methanol. In a further preferred embodiment, the catalyst K1 consists of a mixture of KOMe and NaOMe or a solution of KOMe and NaOMe in methanol.

It is advantageous to use the catalyst K1 in an amount such that an upper limit of 2,500 ppm (about 0.4 mol%) of KOMe with respect to the alcohol (IX) used is maintained in order to reduce the decomposition of the monoethylenically unsaturated alcohol (IX). to avoid. The concentration of potassium ions in step S1 is preferably less than or equal to 0.4 mol%, based on the total amount of the alcohol A1 used, particularly preferably 0.1 to 0.4 mol%. If KOMe is added in such an amount that the concentration is above 0.9 mol% relative to the alkoxylated alcohol (Ia) (product of process step S1), KOMe in the preferred process for preparing the monomers (A1) of the formula (II) I) before step S2 completely or partially separated to obtain a potassium ion concentration of less than 0.9 mol% in step S2. This can be done, for example, by isolating the alkoxylated alcohol A2 after step S1 and optionally purifying it. In a further preferred embodiment, KOMe is used in such an amount that the concentration of potassium ions after the reaction in step S1 is already less than or equal to 0.9 mol% based on (Ia). Step S2 of the preferred process comprises the reaction of the alkoxylated alcohol (Ia) with at least one alkylene oxide of the general formula (Xa) or (Xb) as described above with the addition of an alkaline catalyst K2 to the monomer (A1) of the general formula H ₂ C described above = C (R ¹ ) -R ² -O- (CH ₂ -CH (R ³ ) -O) _k - (CH ₂ -CH (R ⁴ ) -O) i H (I). Preferably, step S2 first comprises the reaction of the alkoxylated alcohol (Ia) with the alkaline catalyst K2. Typically, the alcohol A2 is added to the alkaline catalyst K2 in a pressure reactor. By reduced pressure of typically less than 100 mbar, preferably in the range of 30 to 100 mbar, and / or increasing the temperature, typically in the range of 30 to 150 ° C, water still present in the mixture and / or low boilers can be withdrawn. The alcohol is then present essentially as a corresponding alkoxide. Subsequently, the reaction mixture is typically treated with inert gas (eg nitrogen).

Step S2 preferably comprises the addition of the at least one alkylene oxide (Xa) or (Xb) to the above-described mixture of alcohol (Ia) and alkaline catalyst K2. After completion of the addition of the alkylene oxide (Xa) or (Xb), the reaction mixture is typically allowed to react. The addition of inclusive optional relaxation and including post-reaction is typically over a period of 2 to 36 hours, preferably from 5 to 30 hours, more preferably from 10 to 28 hours, most preferably from 1 to 24 hours.

In the preferred preparation method, the concentration of potassium ions in the reaction in step S2 is less than or equal to 0.9 mol%, preferably less than 0.9 mol%, preferably from 0.01 to 0.9 mol%, particularly preferably from 0 , 1 to 0.6 mol%, based on the alcohol used (Ia).

In a preferred embodiment, the concentration of potassium ions in the reaction in step S2 0.01 to 0.5 mol% based on the alcohol used (la).

In a particularly preferred embodiment, the concentration of potassium ions in the reaction in step S2 is less than or equal to 0.9 mol%, preferably 0.1 to 0.5 mol%, based on the alcohol used (Ia) and the reaction in Step S2 is carried out at temperatures of 120 to 130 ° C.

The alkaline catalyst K2 preferably contains at least one alkaline compound selected from alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal alkoxides (especially C1 to C6 alkoxides, preferably methanolate and / or ethanolate) and alkaline earth alkoxides (especially C1 to C6 alkoxides, preferably methanolate and / or ethanolate). The catalyst K2 preferably contains at least one basic sodium compound, in particular selected from NaOH, NaOMe and NaOEt, more preferably NaOMe or NaOH. As catalyst K2, a mixture of said alkaline compounds can be used, preferably the catalyst K2 consists of one of said basic compounds or mixtures of said alkaline compounds. Frequently, an aqueous solution of the alkaline compounds is used. In another preferred embodiment, the alkaline catalyst K2 is NaOMe or a solution of NaOMe in methanol (MeOH). Typically, a solution of 20 to 50 wt% NaOMe in methanol (MeOH) can be used. Preferably, the catalyst K2 contains no KOMe. In step S2, preference is given to using a catalyst K2 comprising at least one basic sodium compound, in particular selected from NaOH, NaOMe, and NaOEt, the concentration of sodium ions in the reaction in step S2 being in the range from 3.5 to 12 mol%. , preferably from 3.5 to 10 mol%, particularly preferably from 3.5 to 7 mol%, very particularly preferably from 4 to 6 mol%, based on the alcohol used (la).

The reaction in step S2 is carried out at a temperature of less than or equal to 135 ° C., preferably less than or equal to 130 ° C. Preferably, the reaction in step S2 at temperatures of 60 to 135 ° C, preferably at 100 to 135 ° C, more preferably at 120 to 135 ° C, most preferably carried out at 120 to 130 ° C. In particular, step S2 comprises the addition of at least one alkylene oxide (Xa) or (Xb) to a mixture of alcohol (Ia) and alkaline catalyst K2 at a temperature of less than or equal to 135 ° C, preferably less than or equal to 130 ° C, especially at Temperatures of 100 to 135 ° C, preferably at 120 to 130 ° C. Step S2 is preferably carried out at a pressure in the range from 1 to 6 bar, preferably from 1 to 3.1 bar. In order to meet the safety conditions, the reaction in step S2 is preferably carried out at a pressure in the range of less than or equal to 3.1 bar (preferably 1 to 3.1 bar), if R ^{4 is} a hydrocarbon radical having two carbon atoms or a Pressure of less than or equal to 2.1 bar (preferably 1 to 2.1 bar) carried out if R ^{4 is} a hydrocarbon radical having more than 2 carbon atoms. In particular, the addition of alkylene oxide (Xa) or (Xb) and / or the post-reaction are carried out at the above-mentioned pressure. In a further preferred embodiment, the step S2 is performed in a pressure range of 3 to 6 bar absolute. In a further preferred embodiment, the step S2 can be implemented in a pressure range from 0.2 bar to 3.1 bar.

Step S2 preferably comprises the addition of the at least one alkylene oxide (Xa) or (Xb) to a mixture of alcohol (Ia) and alkaline catalyst K2 at a pressure in the range from 1 to 3.1 bar.

In one embodiment, R ^{4 is} a hydrocarbon radical having two carbon atoms, ie an ethyl radical, and step S2 comprises the addition of the at least one alkylene oxide (Xa) or (Xb) to a mixture of alcohol (Ia) and alkaline catalyst K2 at a pressure in the range of 1 to 3.1 bar.

In a further embodiment, radicals R ^{4 is} a hydrocarbon radical having more than two carbon atoms, preferably having three carbon atoms, and step S2 comprises adding the at least one alkylene oxide (Xa) or (Xb) to a mixture of alcohol (Ia) and alkaline catalyst K 2 a pressure in the range of 1 to 2.1 bar.

Step S2 is particularly preferably carried out at a pressure in the range from 1 to 3.1 bar (preferably at the abovementioned pressures) and at a temperature of from 120 to 130 ° C.

Step S2 preferably comprises the addition (including post-reaction time) of the at least one alkylene oxide (Xa) or (Xb) to a mixture of alcohol (Ia) and alkaline catalyst K2 over a period of less than or equal to 36 h, preferably less than or equal to 32 h, more preferably over a period of 2 to 32 h, most preferably over a period of 1 1 to 24 h, and at a pressure of less than or equal to 3.1 bar (preferably at the above pressures).

The described preferred preparation process for the monomers (A1) of the general formula (I) has the advantage that the formation of possibly cross-linking by-products with two ethylenically unsaturated groups is largely avoided. Accordingly, copolymers having a particularly low gel content can be obtained.

Monomers (A1) of the formulas (II) and (III)

In the case of the monomers (A1) of the formulas (II) and (III), R ¹ , R ³ and k or I have the meaning already described for monomers (A1) of the formula (I).

The radical R ⁶ in the monomers (A1) of the formulas (II) and (III) is an aliphatic and / or aromatic, linear, branched or cyclic hydrocarbon radical having 8 to 40 carbon atoms, preferably 12 to 32 carbon atoms. For example, they may be n-alkyl groups such as n-octyl, n-decyl or n-dodecyl groups, phenyl groups and in particular substituted phenyl groups. Substituents on the phenyl groups may be alkyl groups, for example C 1 to C 6 alkyl groups, preferably styryl groups. Particularly preferred is a tristyrylphenyl group.

The hydrophobically associating monomers (A1) of the formulas (II) or (III) and their preparation are known in principle to the person skilled in the art, for example from EP 705 854 A1.

Monomers (A1) of the formula (IV)

In the case of the monomers (A1) of the formula (IV), an ethylenic group H2C = C (R ¹ ) - via a divalent, linking group -R ² -O- with a polyalkyleneoxy radical having a block structure - (CH ² -CH (R ³ ) - 0) k- (CH 2 -CH (R ⁴ ) -O) i - [(CH ₂ -CH (R ⁴ ) -O) h (CH ₂ -CH ₂ -O) i] -R ⁵ wherein the blocks - ( CH ₂ -CH (R ³⁾ -0) _k, - (CH ₂ -CH (R) -0) i and - [(CH (CH ₂ R) -0) h- (CH 2 CH ₂ -0) i] in the in Formula (IV) shown order are arranged. The polyalkyleneoxy group has either a terminal OH group or a terminal ether group OR ⁵ .

The monomers (A1) of the formula (IV), R ^1, R ^2, R ^3, R ^4, R ⁵ and k or I already for monomers (A1) of the formula (I) described meaning.

In monomers (A1) of the formula (IV), h is a number from 0 to 2, preferably from 0 to 1.5, particularly preferably from 0.1 to 1. According to the invention, i in formula (IV) is a number of 1 to 15, preferably from 1, 5 to 10, particularly preferably from 2 to 5.

The block - [(CH 2 -CH (R ⁴ ) -O) h (CH 2 -CH 2 -O) i] is therefore a terminal ethyleneoxy block which optionally contains small amounts of - (CH 2 -CH ( R ⁴ ) -0) units, which are randomly distributed in the ethyleneoxy block.

In a preferred embodiment, the monomers (A1) of the formula (IV) are present in a mixture with monomers (A1) of the formula (I) as a result of the preparation. In this case, the proportion of monomers (A1) of the formula (IV) is from 0.1 to 0.99 mol%, preferably from 0.4 to 0.95 mol%, based on the sum of monomers (A1) of the formula ( I) and monomers (A1) of the formula (IV).

Preparation of the monomers (A1) of the formula (IV)

 The hydrophobically associating monomers (A1) of the formula (VI) can be prepared by methods which are known in principle to those skilled in the art and have already been described in connection with the preparation of hydrophobically associating monomers (A1) of the formula (I).

Thus, the preparation of the monomers (A1) of the formula (IV) in a manner known in principle by alkoxylation of a monoethylenically unsaturated alcohol of the general formula H ₂ C = C (R ¹ ) -R ² -OH (IX) take place.

(IX) kann in einem dreistufigen Verfahren alkoxyliert werden, wobei die ersten beiden Stufen den im Zusammenhang mit dem Herstellverfahren von Monomeren (A1 ) der Formel (I) beschriebenen entsprechen, wobei ein Monomer (A1 ) der Formel (I) erhalten wird, in dem R⁵ für H steht. The alcohol

(IX) can be alkoxylated in a three-stage process, the first two stages corresponding to those described in connection with the preparation of monomers (A1) of the formula (I), wherein a monomer (A1) of the formula (I) is obtained R ^{5 is} H.

The monomers (A1) of the formula (I) thus obtained are reacted with ethylene oxide in a further third step S3, the monomer (A1) of the formula (IV) being formed with R ⁵ = H. This step S3 is carried out in particular without further addition of an alkaline catalyst and is in particular at a pressure in the range of 1 to 7 bar, preferably from 1 to 5 bar, and a temperature in the range of 120 ° C to 140 ° C, particularly preferably of 125 ° C to 135 ° C, carried out. The ethoxylation in step S3 is carried out in particular over a period of 0.5 to 7 hours, in particular from 0.5 to 5 hours, preferably from 0.5 to 4 hours.

The described implementation of the three alkoxylation steps gives a mixture comprising monomers (A1) of the formula (I) and (IV) in the above-described quantitative ratio. The formation of a mixture can be explained as follows: After the second alkoxylation step S2 with alkylene oxides of the formula (Xa) or (Xb), monomers (A1) of the formula (I) with R ⁵ = H are first obtained. In formula (I), depending on the nature of the alkylene oxides used, the polyoxyalkylene chain has a secondary (or even a tertiary) alcohol group as a terminal group, namely a group -CH 2 -CH (R ⁴ ) -OH. Upon further reaction with ethylene oxide in step S3, molecules are formed with terminal, primary OH groups, namely -CH 2 -CH (R ⁴ ) -O-CH 2 -CH 2 -OH. Since primary OH groups are more reactive than secondary or tertiary OH groups, the primary OH groups react preferentially with further ethylene oxide. The ethylene oxide added in step S3 thus does not react uniformly with the monomers (A1) of general formula (I) present after step S2. Once a part of the monomers (A1) of the formula (I) with ethylene oxide to H ₂ C = C (R ¹ ) -R ² -0- (CH ² -CH (R ³ ) -O) k- (CH ₂ - CH (R ⁴ ) -O) i-CH 2 -CH 2 -OH reacts, then react these intermediates preferably with more ethylene oxide. Since the amount of ethylene oxide in step S3 is relatively low, this different reactivity results in that a part of the monomers (A1) of the formula (I) does not react at all, while another part reacts disproportionately. Thus, if one adds p equivalents of ethylene oxide and the proportion of the monomers (A1) of the formula (IV) in the mixture is x, then the value of i = p / x can be calculated from this. Of course, i can also be determined analytically.

Depending on the reaction conditions, the alkoxylation in step S2 proceeds completely or incompletely, so that a small amount of the alkylene oxides (Xa) or (Xb) can remain in the reaction mixture without reacting. This may be the case in particular in the preferred alkoxylation described above at not more than 135 ° C. Residues of the alkylene oxides (Xa) or (Xb) can of course be separated in a conventional manner before the final ethoxylation. But it is also possible to leave these for the alkoxylation in the product. It has been found that the said residual amount of alkylene oxides (Xa) or (Xb) is significantly reduced in the course of step S3. In other words, part of any remaining alkylene oxides (Xa) or (Xb) is converted to the terminal block - [(CH 2 -CH (R ⁴ ) -O) _h - (CH 2 -CH 2 -O) i] in the course of step S3. H, ie it may be a mixed block of alkyleneoxy units - (CH 2 -CH (R ⁴ ) -O) - and ethyleneoxy units - (CH 2 -CH 2 -O) - act. If the alkylene oxides react completely in step S2 or are subsequently separated off in step S2, the terminal block may also be a pure ethyleneoxy block, ie h = 0.

If the terminal OH group of the monomers (A1) of the formula (IV) (that is to say R ⁵ = H) is to be etherified, this can be carried out using the alkylating agents already described in connection with monomers of the formula (I). Particularly preferred preparation process for the monomers (A1) of the formula (IV)

In an advantageous embodiment, the monomers (A1) of the formula (IV) can be prepared by means of the below-described, particularly preferred process. This first comprises the preparation of monomers (A1) of the formula (I) where R ⁵ = H according to the already described particularly preferred preparation process for the monomers (A1) of the formula (I). Starting from the thus obtained compound of the formula (I) where R ⁵ = H, the monomer (A1) of the formula (I) is reacted with ethylene oxide in step S3, preference being given to mixtures comprising monomers (A1) of the formulas (I) and ( IV) arise.

The preferred conditions mentioned below (for example, pressure and / or temperature ranges) in the reactions in step S3 mean that the step is carried out in whole or in part under the conditions indicated. Step S3 is carried out in particular without further addition of an alkaline catalyst. The step S3 is especially at a pressure in the range of 1 to 7 bar, preferably from 1 to 6 bar, most preferably in a range of 3 to 6 bar absolute and a temperature in the range of 60 to 140 ° C, preferably 120 to 140 ° C, more preferably from 120 to 135 ° C performed. The ethoxylation in step S3 is carried out in particular over a period of 0.5 to 7 h, in particular 1 to 5 h, preferably from 1 to 4 h.

Step S3 preferably comprises the addition of ethylene oxide to the reaction mixture after step S2 comprising the monomer (A1) of the general formula (I) without further workup and / or depressurization. After completion of the addition of the ethylene oxide, the reaction mixture is typically allowed to react. The addition of inclusive optional relaxation and including post-reaction is typically over a period of 0.5 to 10 hours, especially from 2 to 10, most preferably from 4 to 8 hours.

The execution of step S3 generally causes alkylene oxide (Xa) or (Xb), which is still present in the reaction mixture after step S2, to be at least partially reacted and thus at least partially removed. It is of course possible to remove alkylene oxide (Xa) or (Xb), which is not reacted after step S2, by a pressure release and / or temperature increase after step S2. Amounts of monomers (A1)

 The amount of monoethylenically unsaturated, hydrophobically associating monomers (A1) is 0.1 to 15.0 wt .-% based on the total amount of all monomers used in the reaction, in particular 0.1 to 10.0 wt .-%, preferably 0 , 2 to 5.0 wt .-% and particularly preferably 0.5 to 2.0 wt .-%.

As a rule, at least 50% by weight, preferably at least 80% by weight of the monomers (A1) are monomers of the general formula (I), (II), (III) and / or (IV) and are preferred only monomers (A1) of the general formula (I), (II), (III) and / or (IV) are used. loading It is particularly preferable to use only monomers (A1) of the general formula (I) for preparing the copolymers of the invention, very particularly preferably monomers (A1) of the general formula (I) in which R ^{2 is} -O- (C _n H 2n) - , Monomers (A2)

 In addition to the monomers (A1), in the reaction at least one different hydrophilic monomer (A2) is used, at least one of the monomers (A2) being a neutral, monoethylenically unsaturated hydrophilic monomer (A2a) selected from the group consisting of of (meth) acrylamide, N-methyl (meth) acrylamide, N, N'-dimethyl (meth) acrylamide and N-methylol (meth) acrylamide. Of course, it is also possible to use mixtures of one or more monomers (A2a) or mixtures of one or more monomers (A2a) with one or more hydrophilic monomers (A2) other than monomer (A2a). The hydrophilic monomers (A2) other than monomer (A2a) are preferably monoethylenically unsaturated monomers.

Further preferably, the hydrophilic monomers (A2) comprise one or more hydrophilic groups in addition to the ethylenic group. These impart sufficient water solubility to the copolymer of the invention because of their hydrophilicity. The hydrophilic groups are, in particular, functional groups which comprise O and / or N atoms. In addition, they may comprise as heteroatoms in particular S and / or P atoms. The monomers (A2) are particularly preferably soluble in water in any desired ratio, but it is sufficient for carrying out the invention that the hydrophobically associating copolymer according to the invention has the aforementioned water solubility. As a rule, the solubility of the monomers (A2) in water at room temperature should be at least 100 g / l, preferably at least 200 g / l and particularly preferably at least 500 g / l.

Examples of suitable functional groups include carbonyl groups> C = O, ether groups - O-, in particular polyethyleneoxy groups - (CH 2 -CH 2 -O) ₀ -, where o preferably represents a number from 1 to 200, hydroxy groups -OH, ester groups -C (0 ) 0, primary, secondary or tertiary amino groups, ammonium groups, amide groups -C (0) -NH-, carboxamide groups - C (0) -NH2 or acidic groups such as carboxyl groups -COOH, sulfonic acid groups -SO3H, phosphonic acid groups -PO3H2 or phosphoric acid groups -OP (OH). 3

Examples of preferred functional groups include hydroxy groups -OH, carboxyl groups -COOH, sulfonic acid groups -SO3H, carboxamide groups -C (0) -NH2, amide groups -C (O) -NH and polyethyleneoxy groups - (CH2-CH2-O) ₀ -H, wherein o preferably stands for a number from 1 to 200. The functional groups may be attached directly to the ethylenic group, or linked to the ethylenic group via one or more linking hydrocarbon groups. The hydrophilic monomers (A2) are preferably monomers of the general formula H ₂ C =C (R ²⁰ ) R ²¹ (XI) where R ^{20 is} H or methyl and R ^{21 is} a hydrophilic group or one of is one or more groups comprising hydrophilic groups.

Examples of suitable monomers (A2) include monomers comprising acidic groups, for example monomers containing COOH groups, such as acrylic acid or methacrylic acid, crotonic acid, itaconic acid, maleic acid or fumaric acid, monomers comprising sulfonic acid groups, such as vinylsulfonic acid, allylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid ( AMPS), 2-methacrylamido-2-methylpropanesulfonic acid, 2-acrylamidobutanesulfonic acid, 3-acrylamido-3-methyl-butanesulfonic acid or 2-acrylamido-2,4,4-trimethylpentanesulfonic acid or monomers comprising phosphonic acid groups, such as vinylphosphonic acid, allylphosphonic acid, N- ( Meth) acrylamidoalkylphosphonsäuren or (meth) acryloyloxyalkylphosphonsäuren.

Also to be mentioned are acrylamide and methacrylamide and derivatives thereof, such as N-methyl (meth) acrylamide, N, N'-dimethyl (meth) acrylamide and N-methylolacrylamide, N-vinyl derivatives such as N-vinylformamide, N-vinylacetamide, N- Vinylpyrrolidone or N-vinylcaprolactam and vinyl esters, such as vinyl formate or vinyl acetate. N-vinyl derivatives can be hydrolyzed after polymerization to vinylamine units, vinyl esters to vinyl alcohol units.

Further examples include monomers containing hydroxyl and / or ether groups, such as, for example, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, allyl alcohol, hydroxyvinylethyl ether, hydroxyvinyl propyl ether, hydroxyvinyl butyl ether or compounds of the formula H ₂ C =C (R ¹ ) -O- (CH ₂ -CH (R ²² ) -O) _b -R ²³ (XII) wherein R ^{1 is} as defined above and b is a number from 2 to 200, preferably 2 to 100. The R ²² radicals are each independently H, methyl or ethyl, preferably H or methyl, with the proviso that at least 50 mol% of the R ²² radicals are H. Preferably, at least 75 mol% of the radicals R ²² are H, more preferably at least 90 mol% and most preferably exclusively H. The radical R ²³ is H, methyl or ethyl, preferably H or methyl. The individual alkyleneoxy units can be arranged randomly or in blocks. For a block copolymer, the transition between the blocks may be abrupt or gradual.

Of course, the abovementioned hydrophilic monomers can be used not only in the acid or base form shown, but also in the form of corresponding salts. It is also possible to convert acidic or basic groups into corresponding salts after the formation of the polymer.

Preference is given to a copolymer in which at least one of the monomers (A2) is a monomer comprising acidic groups, the acidic groups being at least one group selected from the group consisting of -COOH, -SO3H and - PO3H, and salts thereof.

At least one of the monomers (A2) is preferably a monomer selected from the group consisting of (meth) acrylic acid, vinylsulfonic acid, allylsulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid (AMPS), particularly preferably acrylic acid and / or APMS or their salts.

In a preferred embodiment, the at least one hydrophilic monomer (A2) comprises two different monomers.

Further preferably, the at least one hydrophilic monomer (A2) comprises at least two different monoethylenically unsaturated hydrophilic monomers (A2a) and (A2b), wherein (A2a) is as defined above; and

(A2b) at least one anionic, monoethylenically unsaturated hydrophilic monomer

 (A2b) containing at least one acidic group selected from the group consisting of -COOH, -SO3H or -PO3H2. In a preferred embodiment

(A2a) as defined above; and

(A2b) at least one anionic, monoethylenically unsaturated hydrophilic monomer

 (A2b) containing at least one -SOsH group.

The at least one neutral monomer (A2a) is preferably (meth) acrylamide, in particular acrylamide. If mixtures of different monomers (A2a) are used, at least 50 mol% of the monomers (A2a) should be (meth) acrylamide, in particular acrylamide.

The at least one hydrophilic, monoethylenically unsaturated anionic monomer (A2b) is preferably a monomer comprising -COOH groups and / or -SO3H groups, particularly preferably a monomer comprising -SOsH groups. Of course, it may also be a salt of the acidic monomer. Suitable counterions include in particular alkali metal ions such as Li ⁺ , Na ⁺ or K ⁺ and ammonium ions such as ΝΗ ₄ ⁺ or ammonium ions with organic radicals.

Examples of monomers comprising COOH groups include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid or fumaric acid. Preference is given to acrylic acid.

Examples of monomers having sulfonic acid groups include vinylsulfonic acid, allylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid, 2-acrylamidobutanesulfonic acid, 3-acrylamido-3-methyl-butanesulfonic acid or 2-acrylonitrile. amido-2,4,4-trimethylpentane. Preference is given to vinylsulfonic acid, allylsulfonic acid or 2-acrylamido-2-methylpropanesulfonic acid and particular preference is given to 2-acrylamido-2-methylpropanesulfonic acid. Examples of monomers comprising phosphonic acid groups include vinylphosphonic acid, allylphosphonic acid, N- (meth) acrylamidoalkylphosphonic acids or (meth) acryloyloxyalkylphosphonic acids, preference being given to vinylphosphonic acid.

For the sake of completeness, it should be mentioned that the monomers (A2a) may, under certain circumstances, at least partially hydrolyze to (meth) acrylic acid in the course of their preparation and use. Accordingly, the copolymers used according to the invention may comprise (meth) acrylic acid units, even if no (meth) acrylic acid units were used for the synthesis. The tendency for hydrolysis of the monomers (A2a) decreases with increasing content of sulfonic acid groups. Accordingly, the presence of sulfonic acid group is recommended in the copolymer used in the present invention.

In addition, in the reaction to the copolymers used according to the invention, at least one monoethylenically unsaturated, cationic, ammonium ion-containing monomer (A2c) may optionally be used.

Suitable cationic monomers (A2c) include, in particular, ammonium-containing monomers, in particular ammonium derivatives of N- (co-aminoalkyl) (meth) acrylamides or (δ-aminoalkyl (meth) acrylic esters.) In particular, ammonium-containing monomers (A2c) may be compounds of the formula (A) general formulas H ₂ C =C (R ⁸ ) -C (O) -NR ⁹ -R ¹⁰ -NR ¹ VX "^" (XIIIa) and / or H ₂ C =C (R ⁸ ) -C (O) -OR -NR ¹⁰ VX ^"" (XI IIb) act. In this case, R ⁸ represents H or methyl, R ⁹ is H or a C to _C4 alkyl group, preferably H or methyl and R ¹⁰ represents a preferably linear Cr to C ₄ Alkylene group, for example a 1, 2-ethylene group -CH ₂ -CH ₂ - or a 1, 3-propylene group -CH ₂ -CH ₂ -CH ₂ -.

The radicals R ¹¹ are, independently of one another, C 1 -C ₄ -alkyl radicals, preferably methyl or a radical of the general formula -R ¹² -SOsH, where R ^{12 is} a preferably linear C ₄ -C ₄ -alkylene group or a phenyl group, with the proviso that it is usually not more than one of the substituents R ¹¹ is a sulfonic acid groups having substituents. Particularly preferably, the three substituents R ¹¹ are methyl groups, that is, the monomer has a group -N (CH 3) 3 ⁺ . X "^" in the above formula is a monovalent anion, for example CK of course, X "- may also represent a corresponding fraction of a polyvalent anion, although this is not preferred Examples of preferred monomers (A2c) of the general formula (XIIIa) or XIIIb) include salts of 3-trimethylammonium-propyl (meth) acrylamides or 2-trimethylammoniumethyl (meth) acrylates, for example the corresponding chlorides such as Trimethylammoniumpropylacrylamide chloride (DIMAPAQUAT) and 2-

Trimethylammoniumethyl methacrylate chloride (MADAME-QUAT).

In addition, further monomers other than the hydrophilic monomers (A2a), (A2b) and (A2c) can be used in the conversion to the copolymers used according to the invention, and other monoethylenically unsaturated hydrophilic monomers (A2d) which are different from the hydrophilic monomers (A2a). Examples of such monomers include monomers comprising hydroxyl and / or ether groups, for example hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, allyl alcohol, hydroxyvinylethyl ether, hydroxyvinylpropyl ether, hydroxyvinyl butyl ether or compounds of the formula H ₂ C =C (R ¹ ) - C (O) -O- (CH ₂ -CH (R ³ ) -O) _b -R ¹⁴ (XlVa) or H ₂ C = C (R ¹ ) -O- (CH ₂ -CH (R ³ ) - 0) _b -R ¹⁴ (XIVb) where R ^{1 is} as defined above and b is a number from 2 to 200, preferably 2 to 100. The radicals R ¹³ are each independently H, methyl or ethyl, preferably H or methyl, with the proviso that at least 50 mol% of the radicals R ¹³ is H. Preferably, at least 75 mol% of the radicals R ¹³ are H, more preferably at least 90 mol% and most preferably exclusively H. The radical R ¹⁴ is H, methyl or ethyl, preferably H or methyl. Further examples of monomers (A2d) include N-vinyl derivatives such as N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone or N-vinylcaprolactam and vinyl esters such as vinyl formate or vinyl acetate. N-vinyl derivatives can be hydrolyzed after polymerization to vinylamine units, vinyl esters to vinyl alcohol units.

The amount of all hydrophilic monomers (A2) in the copolymer of the invention is according to the invention 85.0 to 99.9 wt .-% based on the total amount of all monomers in the copolymer, preferably 90.0 to 99.9 wt .-%, preferably 95.0 by weight to 99.8. ^'%, and particularly from 98.0 to 99.5 wt forthcoming Trains t .-%.

The amount of neutral, hydrophilic monomers (A2a) is generally 30 to 95 wt .-%, preferably 30 to 85 wt .-% and particularly preferably 30 to 70 wt .-% with respect to the total amount of all monomers used.

If the copolymer comprises only neutral monomers (A2a) and anionic monomers (A2b), it has been found that the neutral monomers (A2a) in an amount of 30 to 95 wt .-% and the anionic monomers (A2b) in an amount of 4 , 9 to 69.9 wt .-%, wherein the amount is based on the total amount of all monomers used. In this embodiment, the monomers (A2a) are preferably used in an amount of 30 to 80% by weight and the anionic monomers (A2b) in an amount of 19.9 to 69.9% by weight, and the monomers are particularly preferred (A2a) used in an amount of 40 to 70 wt .-% and the anionic monomers (A2b) in an amount of 29.9 to 59.9 wt .-% If the copolymer is neutral monomers (A2a), anionic monomers (A2b) and cationic monomers (A2c), it has been found that the neutral monomers (A2a) are in an amount of 30 to 95% by weight and the anionic (A2b) and cationic monomers (A2c) together in an amount of 4.9 to 69.9 wt .-%, with the proviso that the molar ratio (A2b) / (A2c) is 0.7 to 1.3. The molar ratio (A2b) / (A2c) is preferably 0.8 to 1.2 and, for example, 0.9 to 1.1. By this measure, copolymers can be obtained which react particularly insensitive to salt load. In this embodiment, preference is given to using the monomers (A2a) in an amount of 30 to 80% by weight and the anionic and cationic monomers (A2b) + (A2c) together in an amount of 19.9 to 69.9% by weight and more preferably, the monomers (A2a) are used in an amount of 40 to 70% by weight, and the anionic and cationic monomers (A2b) + (A2c) are used together in an amount of 29.9 to 59.9% by weight , wherein in each case the already mentioned molar ratio should be maintained.

Monomers (A3)

 In addition to the monomers (A1) and (A2), various ethylenically unsaturated monomers, preferably monoethylenically unsaturated monomers (A3), can be used in the reaction, optionally of the monomers (A1) and (A2). Of course, mixtures of several different monomers (A3) can also be used.

Such monomers can be used to fine tune the properties of the copolymer used in the present invention. If present at all, the amount of such optionally present monomers (A3) can be up to 14.9 wt .-%, preferably up to 9.9 wt .-%, particularly preferably up to 4.9 wt .-%, each based on the total amount of all monomers used. Most preferably, no monomers (A3) are present.

The monomers (A3) may be, for example, monoethylenically unsaturated monomers which have a more hydrophobic character than the hydrophilic monomers (A2) and which accordingly are only slightly water-soluble. As a rule, the solubility of the monomers (A3) in water at room temperature is less than 50 g / l, in particular less than 30 g / l. Examples of such monomers include N-alkyl and N, N "dialkyl (meth) acrylamides wherein the number of carbon atoms in the alkyl groups together is at least 3, preferably at least 4. Examples of such monomers include N-butyl (meth) acrylamide, N Cyclohexyl (meth) acrylamide or N-benzyl (meth) acrylamide.

Surfactants (B)

 The aqueous formulation used according to the invention further comprises at least one surfactant (B), wherein the at least one surfactant (B) is selected from the group consisting of nonionic surfactants (B1) having an HLB value of more than 1 1, anionic surfactants (B2 ), cationic surfactants (B3) and zwitterionic surfactants (B4).

The at least one surfactant (B) is further particularly preferred in an amount of at least 0.5 and less than 50.0 ppm, preferably from 0.5 to 40.0 ppm, more preferably from 0.5 to 30.0 ppm from 1, 0 to 20.0 ppm, more preferably from 2.5 to 15 ppm and particularly preferably from 5.5 to 10 ppm, based on the total amount of the aqueous formulation used. The term "ppm-per-million" refers to parts by weight, ie at least 0.5 and less than 50 ppm of the at least one surfactant (B), based on the total amount of the formulation, is used 5.0 x 10 ^"5 and less than 0.005 wt .-%, preferably from 5.0 ^χ 10 ^{" 5} to 0.004 wt .-%, particularly preferably 5.0 ^χ 10 ^"5 to 0.003 wt .-%, preferably from 0.0001 to 0.002 wt .-%, more preferably from 0.00025 to 0.0015 wt .-%, and particularly preferably from 0.00055 to 0.001 wt .-% of at least one surfactant (B).

The at least one surfactant (B) may in principle be any nonionic surfactants (B1) having an HLB value of more than 1 liter, anionic surfactants (B2), cationic surfactants (B3) and zwitterionic surfactants (B4) provided they are basically suitable for tertiary oil production. Preferably, the addition of the at least one surfactant (B) lowers the viscosity of the aqueous formulation according to the invention. Accordingly, the at least one surfactant (B) is a viscosity-reducing surfactant, in particular a surfactant, which lowers the viscosity of the aqueous formulation of the invention containing at least one water-soluble, hydrophobically associating copolymer (A). Corresponding surfactants are known in principle to the person skilled in the art. Suitable surfactants for tertiary mineral oil extraction comprise as hydrophobic moieties, in particular hydrocarbon radicals, preferably aliphatic hydrocarbons having 5 to 36 carbon atoms.

Examples of such surfactants include anionic surfactants with sulfonic acid groups such as olefinsulfonates, for example α-olefinsulfonates or i-olefinsulfonates, paraffin-sulfonates or alkylbenzenesulfonates, nonionic surfactants such as alkylpolyalkoxylates, in particular alkylpolyethoxylates and alkylpolyglucosides. Furthermore, they can be surfactants which comprise both nonionic hydrophilic groups and anionic hydrophilic groups, for example alkyl ether sulfonates, alkyl ether sulfates or alkyl ether carboxylates.

Furthermore, it may also be oligomeric or polymeric surfactants. Examples of such surfactants include amphiphilic block copolymers comprising at least one hydrophilic and at least one hydrophobic block. Examples include polypropyleneoxy-polyethyleneoxy block copolymers, polyisobutylene-polyethyleneoxy block copolymers and comb polymers having polyethyleneoxy side chains and a hydrophobic backbone, wherein the backbone preferably comprises substantially olefins or (meth) acrylates as building blocks.

The at least one surfactant (B) is preferably a surfactant which is different from the above-described monomers (A1), (A2) or (A3).

Preferably, the at least one surfactant (B) is a nonionic surfactant (B1) or an anionic surfactant (B2). In one embodiment, mixtures of several surfactants (B) can be used, which is preferably a mixture of two or more nonionic surfactants (B1) or mixtures of two or more anionic surfactants (B2). In a preferred embodiment, the at least one nonionic surfactant (B1) is a surfactant having an HLB value of more than 1 1, preferably at least 12, preferably at least 13 and particularly preferably at least 13.5. The at least one nonionic surfactant (B1) is particularly preferably a surfactant with an HLB value of 12 to 17.

wobei ML das Molekulargewicht der lipophilen Anteile und MG das Gesamtgewicht angibt. Nähere Einzelheiten hierzu finden sich in H.-D. Dörfer, Grenzflächen und kolloid-disperse Systeme, Springer Verlag 2002, Kapitel 9.3„Physikalische Eigenschaften und Wirkungen der Tenside". Generally, the HLB value is defined by the formula

where ML is the molecular weight of the lipophilic moieties and MG is the total weight. Further details can be found in H.-D. Villages, Interfaces and Colloidal Disperse Systems, Springer Verlag 2002, Chapter 9.3 "Physical Properties and Effects of Surfactants".

In a preferred embodiment, the at least one surfactant (B) is a nonionic surfactant (B1 a) according to formula (V)

R ⁱ⁵ _o- (CH ₂ -CH ₂ -O) _m -H (V).

In the above formula (V), R ^{15 represents} an acyclic, saturated, branched hydrocarbon group having 5 to 25 carbon atoms, preferably 7 to 20 carbon atoms, more preferably 9 to 15 carbon atoms and, for example, 13 carbon atoms.

According to the invention, m is a number from 7 to 20, preferably 8 to 15.

In a preferred embodiment of the invention, the surfactant (B) is thus a surfactant (B1 a) according to formula (VII), where the radicals and indices have the following meaning:

R ¹⁵ : is an acyclic, saturated, branched hydrocarbon radical having 5 to 25 carbon atoms, preferably 9 to 15 carbon atoms, more preferably 13 carbon atoms;

 m: is a number from 7 to 20, preferably from 8 to 15.

The radical R ¹⁵ preferably has a degree of branching of from 0.4 to 2.5, preferably from 2.0 to 2.5. The term "degree of branching" is defined here in a manner known in principle as the number of methyl groups in a molecule of the underlying hydrocarbon radical minus 1. The mean degree of branching is the statistical mean of the degrees of branching of all molecules in a sample. In a further preferred embodiment, the at least one surfactant (B) is thus a nonionic surfactant (B1 b) according to formula (VI) R ¹⁶ -C (O) -NH- (CH ₂ -CH ₂ -O) ₀ -H (VI ).

In the above formula (VI), R ^{16 represents} an aliphatic, branched or unbranched, unsaturated hydrocarbon group having 10 to 30 carbon atoms, preferably 16 to 24 carbon atoms, for example, 17 carbon atoms. R ¹⁶ is preferably an aliphatic, unbranched, unsaturated hydrocarbon radical having 10 to 30 carbon atoms, preferably 16 to 24 carbon atoms, for example 17 carbon atoms. More preferably R ^{16 is} an aliphatic, unbranched, monounsaturated hydrocarbon radical having 16 to 24 carbon atoms, for example 17 carbon atoms. According to the invention o is a number from 7 to 15, preferably 8 to 12, particularly preferably 10.

In a preferred embodiment of the invention, the surfactant (B) is a surfactant (B1 b) according to formula (VI), where the radicals and indices have the following meaning:

R ¹⁶ : is an aliphatic, branched or unbranched, unsaturated hydrocarbon radical having 10 to 30 carbon atoms, preferably 16 to 24 carbon atoms;

o: is a number from 7 to 15, preferably 8 to 12. In a further preferred embodiment, the at least one surfactant (B) is at least one anionic surfactant (B2a) of the general formula R ¹⁷ -X ^" M1 ⁺ (VII).

In the formula (VII), R ^{17 is} a saturated or unsaturated, aliphatic and / or aromatic, linear or branched hydrocarbon radical having 8 to 40 carbon atoms.

R ¹⁷ is preferably an aliphatic saturated or unsaturated, linear or branched hydrocarbon radical having 8 to 25 carbon atoms, particularly preferably a linear, saturated hydrocarbon radical having 8 to 20, preferably 10 to 14 and, for example, 12 carbon atoms.

Erfindungsgemäß steht M1 ⁺ für ein Kation, bevorzugt für ein Kation ausgewählt aus der Gruppe bestehend aus Na⁺, K⁺, Li⁺, Nh , H⁺, Mg²⁺ und Ca²⁺, insbesondere bevorzugt um Na⁺. Besonders bevorzugt handelt es sich bei dem mindestens einen anionischen Tensid (B2a) um Dodecylsulfonat, insbesondere bevorzugt um Natriumdodecylsulfonat. According to the invention, X represents -SO ₃ -, -O-SO ₃ -, -CO ₂ -, -ΡO ₃ ^{2 "} or -O-PO ₃ -, preferably for

According to the invention M1 ^{+ is} a cation, preferably a cation selected from the group consisting of Na ⁺ , K ⁺ , Li ⁺ , Nh, H ⁺ , Mg ²⁺ and Ca ²⁺ , particularly preferably Na ⁺ . The at least one anionic surfactant (B2a) is particularly preferably dodecylsulfonate, particularly preferably sodium dodecylsulfonate.

In a preferred embodiment, the at least one surfactant (B) is at least one anionic surfactant (B2a) of the general formula (VII), where the radicals and indices have the following meanings:

R ¹⁷ : is a saturated or unsaturated, aliphatic and / or aromatic, linear or branched hydrocarbon radical having 8 to 40 carbon atoms; preferably a linear, saturated hydrocarbon radical having 8 to 20 carbon atoms;

X- is -SO ₃ -, -O-SO ₃ -, -CO ² -, -PO 3 ² - or -O-PO ₃ -; preferably -SO 3 -; or

M1 ⁺ : is a cation, preferably Na ⁺ . In a further preferred embodiment, the at least one surfactant (B) is at least one anionic surfactant (B2b) of the general formula R ¹⁸ -O- (CH ₂ -CH (R ¹⁹ ) -O) _p -YZ-M2 ⁺ (VIII). where the radicals and indices have the following meaning:

R ¹⁸ : is a saturated or unsaturated, aliphatic and / or aromatic, linear or branched hydrocarbon radical having 8 to 40 carbon atoms; preferably a linear, saturated hydrocarbon radical having 8 to 20 carbon atoms;

R ¹⁹ : is independently H, methyl or ethyl, provided that at least 50 mol% of R ³ is H; preferably H;

 p: is a number from 0.1 to 30; preferably 7 to 20;

 Y: is a single bond or a divalent linking one

 Group - (Cfhta) -, wherein f is a natural number from 1 to 5; preferably a single bond or a divalent linking group - (Cfhta) -, wherein f is an integer from 1 to 3;

Z: is -SO3-, -CH ₂ C0 ₂ - or -PO3 ² -; preferably -S0 ₃ - _;

M2 ⁺ : is a cation, preferably Na +.

In the above general formula (VIII), Y represents a single bond or a divalent linking group - (Cfhta) -, wherein f is a natural number of 1 to 5. According to a preferred embodiment of the invention, Y is a methylene, -CH 2 -; Ethylene, -CH 2 CH 2 -; or propylene group, -CH 2 CH 2 CH 2 -.

In a preferred embodiment, in the above formula (VIII) Y represents a single bond and Z is a -S03 ^"group. In this case, it is at least the egg nem surfactant of the formula (VIII) is an a sulfate Group of surfactant.

In a further preferred embodiment, in the above formula (VIII), Y is a divalent linking group - (CfH 2f) -, where f is a natural number from 1 to 5, preferably is 1 to 3, and Z is an -SO 3 ^" group, in which case the at least one surfactant of the formula (VIII) is a surfactant carrying a sulfonate group.

In a further preferred embodiment, Y is a single bond and Z is a CH ₂ C0 ₂ group.

Preferred surfactants (B2b) of the formula VIII are R ¹⁸ -O- (CH ₂ -CH ₂ -O) ₂ -SO ₃ Na, where R ^{18 is} a lauryl or cocoyl radical and also C 16 -C ¹⁸ -CH- (CH ₂ -CH 2 -O) io-CH2-COONa. Preferably, the at least one surfactant (B) has an adsorption of greater than or equal to 1 mg / m ² , preferably greater than or equal to 1, 5 mg / m ² , more preferably greater than or equal to 2 mg / m ² of those in the Erdöllagerstätte at least partially existing rock surfaces. The reported value of more than 1 mg / m ² refers to values determined by static adsorption on rock samples (further details can be found in API Recommended Practice 63 (RP 63), First Edition, June 1, 1990).

A = adsorption [mg / g],

W _s = weight of the rock sample (g)

W _e = weight of the surfactant solution (g)

 Ci = initial concentration of the surfactant (mg / g)

C _f = final concentration of the surfactant (mg / g) respectively

A = adsorption [mg / m ² ],

W _s = surface of the rock sample (m ² )

W _e = weight of the surfactant solution (mg)

 Ci = initial concentration of the surfactant (mg / g)

C _f = final concentration of the surfactant (mg / g).

In a suitable method for determining the amount of the respective surfactant adsorbed by the rock surface, comminuted (optionally ground) and purified rock is mixed with an aqueous solution of the surfactant and, after adjusting the equilibrium, the remaining surfactant concentration in the aqueous solution is measured by liquid chromatography (HPLC). rock surface

 For the purposes of the present invention, rock is preferably all rocks occurring in petroleum formations or other subterranean formations, preferably porous or fissured sedimentary rocks, for example silicate and carbonate rocks.

Silicate rocks consist at least partially, preferably predominantly of hard silicates such as feldspar, quartz, amphibole, pyroxene, olivine or foam. Preferably, it is quartz or sandstone.

Suitable carbonate rocks are, for example, limestone and dolomite.

By adding at least 0.5 and less than 50.0 ppm of at least one surfactant (B) to the aqueous formulation used according to the invention, the viscosity of the formulation is lowered. Accordingly, the polymers can be more easily pressed into the formation.

In a preferred embodiment, the at least one surfactant (B) then at least partially adsorbs to the rock surfaces present in the petroleum reservoirs in the petroleum-bearing formation and is thus at least partially removed from the aqueous formulation. This leads to an increase in viscosity until almost the initial viscosity of the formulation before the addition of the at least one surfactant (B), that is, an effective reduction in aqueous phase mobility is achieved.

In order to enhance the positive effect obtained by the addition of at least one surfactant (B), the at least one surfactant (B) can be chosen depending on the type of rock surface predominant in the formation. For use in oil reservoirs, which for the most part have carbonate rocks, preference is given to using anionic or nonionic surfactants, in particular nonionic surfactants for use in silicate rocks.

Preparation of hydrophobically associating copolymers

The copolymers used according to the invention can be prepared by methods known in principle by free-radical polymerization of the monomers (A1) and (A2) and optionally (A3), for example by solution or gel polymerization in the aqueous phase. For the polymerization, the monomers (A1), (A2), optionally (A3), initiators and optionally further auxiliaries for polymerization in an aqueous medium are used. In a preferred embodiment, the preparation is carried out by means of gel polymerization in an aqueous phase. For the gel polymerization, a mixture of the monomers (A1), (A2) and optionally (A3), initiators and optionally further excipients with water or an aqueous solvent mixture is first provided. Suitable aqueous Lösemit- telgemische include water and water-miscible organic solvents, wherein the proportion of water is usually at least 50 wt .-%, preferably at least 80 wt .-% and particularly preferably at least 90 wt .-%. Suitable organic solvents here are in particular water-miscible alcohols, such as methanol, ethanol or propanol. Acidic monomers can be completely or partially neutralized prior to polymerization. The concentration of all components except the solvents in the course of the polymerization is usually about 20 to 60 wt .-%, preferably about 30 to 50 wt .-%. The polymerization should be carried out in particular at a pH in the range from 5.0 to 7.5 and preferably at a pH of about 6.0. Polymerization in the presence of a non-polymerizable surface-active compound

In a preferred embodiment of the invention, in the reaction of the at least one monoethylenically unsaturated hydrophobically associating monomer (A1) with the at least one hydrophilic monomer (A2) other than monomer (A1) prior to the initiation of the polymerization reaction, at least one further nonpolymerizable surface-active compound ( O) used.

The non-polymerizable surface-active compound (O) is preferably at least one surfactant. Preferably, it is at least one nonionic surfactant (01), but anionic surfactants (02) and cationic surfactants (03) are also suitable, provided that they do not participate in the polymerization reaction.

Preference is given to nonionic surfactants (01) of the general formula R ²⁰ -Y ', where R ^{20 is} a hydrocarbon radical having 8 to 32, preferably 10 to 20 and particularly preferably 12 to 18 carbon atoms and Y' is a hydrophilic group, preferably a non-ionic hydrophilic group, in particular a polyalkyleneoxy group.

The at least one nonionic surfactant (01) is preferably an ethoxylated long-chain aliphatic alcohol which may optionally contain aromatic moieties.

Examples of its called: Ci2Ci4 fatty alcohol ethoxylates, Ci6Ci8 fatty alcohol ethoxylates, C13 oxo alcohol ethoxylates, Cio-Oxoalkoholethoxylate, Ci3Ci5-Oxoalkoholethoxylate,

Cio-Guerbet alcohol ethoxylates and alkylphenol ethoxylates. Compounds having 5 to 20 ethyleneoxy units, preferably 8 to 18 ethyleneoxy units, have proven particularly suitable. Optionally, even small amounts of higher alkyleneoxy units, in particular propyleneoxy and / or butyleneoxy units may be present, but the amount of ethyleneoxy units should generally be at least 80 mol% with respect to all alkyleneoxy units. Surfactants selected from the group of ethoxylated alkylphenols, ethoxylated, saturated iso-C 13 -alcohols and / or ethoxylated C 10 -guerbetalcohols are particularly suitable, in each case 5 to 20 ethyleneoxy units, preferably 8 to 18 ethyleneoxy units in alkoxy radicals available.

The at least one non-polymerizable surface-active compound (O) may be the same or different from the at least one surfactant (B). In one embodiment, the non-polymerizable surface-active compound (O) corresponds to the at least one surfactant (B).

In a further embodiment, the at least one non-polymerizable, surface-active compound (O) is different from the at least one surfactant (B).

By adding a non-polymerizable surfactant compound (O) during the polymerization of the hydrophobically associating copolymer (A), the performance characteristics of the copolymer in polymer flooding can be modified. In particular, the thickening effect is increased and, moreover, the gel fraction of the copolymer is reduced.

This effect can presumably be explained as follows: In the polymerization without the presence of at least one nonpolymerizable, surface-active compounds (O), the hydrophobically associating comonomers (A) form micelles in the aqueous reaction medium. In the polymerization, this leads to the fact that the hydrophobically associating regions are incorporated in blocks in the polymer. If an additional surface-active compound (O) is present in the preparation of the copolymers, mixed micelles form. These mixed micelles contain polymerizable and non-polymerizable moieties. As a result, the hydrophobically associating monomers are incorporated in shorter blocks. At the same time, the number of these shorter blocks per polymer chain is larger. Thus, the structure of the copolymers prepared in the presence of non-polymerizable surface-active compounds (O) differs from those prepared in the absence of such a compound. The non-polymerizable, surface-active compounds (O) can generally be used in an amount of 0.1 to 5 wt .-% with respect to the amount of all monomers used.

The weight ratio of the nonpolymerizable, surface-active compounds (O) used to the monomers (A1) is generally 4: 1 to 1: 4, preferably 2: 1 to 1: 2, particularly preferably 1: 5: 1 to 1 : 1, 5 and for example about 1: 1. Carrying out the polymerization

 For the polymerization, the required components are first mixed together. It does not matter in the order in which the components are mixed for polymerization, it is only important that in the preferred polymerization method the non-polymerizable surfactant (O) is added to the aqueous polymerization medium prior to the initiation of the polymerization.

The mixture is then thermally and / or photochemically polymerized, preferably at -5 ° C to 80 ° C. If thermally polymerized, preference is given to using polymerization initiators which can initiate the polymerization even at a comparatively low temperature, for example redox initiators. The thermal polymerization can be carried out even at room temperature or by heating the mixture, preferably to temperatures of not more than 50 ° C. The photochemical polymerization is usually carried out at temperatures of -5 to 10 ° C. It is also possible to combine photochemical and thermal polymerization by adding to the mixture both thermal and photochemical polymerization initiators. The polymerization is first started photochemically at low temperatures, preferably -5 to + 10 ° C. The liberated heat of reaction heats up the mixture, which additionally initiates thermal polymerization. By means of this combination, a turnover of more than 99% can be achieved.

In a further preferred embodiment of the polymerization, the reaction can also be carried out with a mixture of a redox initiator system and a thermal initiator which decomposes only at relatively high temperatures. This may be, for example, a water-soluble azo initiator which decomposes in the temperature range from 40.degree. C. to 70.degree. The polymerization starts here at low temperatures of, for example, 0 to 10 ° C by the redox initiator system. As a result of the released heat of reaction, the mixture heats up and, in addition, the polymerization is started by the initiator which decomposes only at relatively high temperatures.

The gel polymerization is usually carried out without stirring. It can be carried out batchwise by irradiating and / or heating the mixture in a suitable vessel at a layer thickness of 2 to 20 cm. The polymerization produces a solid gel. The polymerization can also be continuous. For this purpose, use is made of a polymerization apparatus which has a conveyor belt for receiving the mixture to be polymerized. The conveyor belt is equipped with means for heating and / or for irradiation with UV radiation. Thereafter, the mixture is poured on by means of a suitable device at one end of the band, in the course of transport in the band direction, the mixture polymerizes and at the other end of the band can remove the solid gel.

The resulting gel is preferably comminuted and dried after the polymerization. The drying should preferably be carried out at temperatures below 100 ° C. To avoid By gluing one can use a suitable release agent for this step. The hydrophobically associating copolymer is obtained as granules or powder.

Further details for carrying out a gel polymerization are disclosed, for example, in DE 10 2004 032 304 A1, Sections [0037] to [0041].

Since the polymer powder or granules obtained in the course of use in the field is usually used as an aqueous solution, the polymer must be dissolved in place in water. This can lead to unwanted clumping with the described high molecular weight polymers. In order to avoid this, an additive which accelerates or improves the dissolution of the dried polymer in water can already be added to the polymers according to the invention during the synthesis. This aid may be, for example, urea. Properties of the copolymers

The copolymers obtained preferably have a weight average molecular weight M _w of 1 ^* 10 ⁶ g / mol to 30 ^* 10 ⁶ g / mol, preferably 5 ^* 10 ⁶ g / mol to 20 ^* 10 ⁶ g / mol.

Preferably, such copolymers are used for the process, which is characterized by a particularly low shear degradation.

The term "shear degradation" is defined as the percentage permanent change in the viscosity of a polymer solution after shearing the polymer solution under certain conditions. "Permanent" means that the loss of viscosity is retained even after the shear stress has ceased and not, as with pseudoplastic (shear thinning ) Behavior is reversible when eliminating the shear stress.

Shear degradation of high molecular weight solutions of polymers can occur if the mechanical stress on the polymer solutions due to shear is high enough to cause breakage of polymer chains (see, for example, JM Maerker, Shear Degradation of partially hydrolyzed Polyacrylamide Solutions, SPE Journal 15 (4), 1975, pages 311-322 or RS Seright, "The Effects of Mechanical Degradation and Viscoelastic Behavior on Injectivity of Polyacrylamide Solutions", SPE Journal 23 (3), 1983, pages 475-485). As a result, the proportion of long polymer chains in the polymer solution is reduced, and accordingly, the viscosity of the polymer solution decreases irreversibly.

The shear degradation of polymers can be measured by means of a capillary shear test according to API RP 63. For measurement, a solution of the polymer is forced under pressure through a narrow capillary. The viscosity of the polymer solution before and after pressing through the capillary is determined in each case. The shear stress of the polymer can be adjusted by the pressure at which the solution is forced through the capillary, the length and diameter of the capillary and the viscosity of the polymer solution (ie ultimately the concentration of the polymer solution). The Details of the performance of the capillary shear test according to API RP 63 are given in the examples section of this invention, to which reference is hereby expressly made.

The shear degradation of the copolymers used for the process according to the invention, measured by means of a capillary shear test according to API RP 63 under the conditions specified in the example, is preferably less than 10%, more preferably less than 8%. Due to this preferred property, the amount of copolymer used can be kept lower than in copolymers which have higher shear degradation.

Process for the extraction of oil

 To carry out the method according to the invention, at least one production well and at least one injection well are sunk into the crude oil deposit. As a rule, a deposit is provided with multiple injection wells and multiple production wells. The at least one injection well injects an aqueous formulation of the described copolymer into the oil reservoir and removes oil from the reservoir through at least one production well. The term "petroleum" in this context, of course, not only pure phase oil meant, but the term also includes the usual crude oil-water emulsions.The pressure generated by the pressed-in formulation, the so-called "polymer flood", the petroleum flows in the direction the production well and is funded through the production well.

The porosity (more correctly referred to as "permeability") of a petroleum formation is given by one skilled in the art in the unit "Darcy" (abbreviated "D" or "mD" for "Millidarcy") and may be a function of the flow rate of a liquid phase in the petroleum formation The flow rate can be determined in nuclear flooding experiments with cores taken from the formation, details of which can be found, for example, in K. Weggen, G. Pusch, H. Rischmüller in "Oil and Gas", pages 37 ff., Ulmann's Encyclopedia of Industrial Chemistry, Online Edition, Wiley-VCH, Weinheim 2010. It will be understood by those skilled in the art that the permeability in an oil reservoir need not be homogeneous, but generally has a certain distribution, and, accordingly, the permeability of a Crude oil deposit around an average permeability.

According to the invention, it is a deposit with an average permeability of 10 mD to 4 D, preferably 100 mD to 2 D and particularly preferably 200 mD to 1 D.

The storage temperature is 30 ° C to 150 ° C, preferably 40 ° C to 100 ° C and more preferably 50 ° C to 80 ° C. Aqueous formulation

To carry out the process, an aqueous formulation is used which, in addition to water, comprises at least one hydrophobically associating copolymer (A) and at least one surfactant (B). Of course, mixtures of several copolymers (A) and mixtures of several surfactants (B) can be used.

The formulation can be prepared in fresh water, but also in salts containing water. For example, seawater can be used or it can be used promoted formation water, which is reused in this way. For production platforms in the sea, the formulation is usually applied in seawater. In the case of conveyors on land, the copolymer can advantageously be first dissolved in fresh water and the solution obtained can be diluted with formation water to the desired use concentration. The formulation may preferably be prepared by initially charging the water, scattering the copolymer as a powder and mixing it with the water. The addition of the at least one surfactant (B) may be carried out prior to the addition of the copolymer, simultaneously or subsequently. Preferably, the addition of the at least one surfactant (B) to the formulation occurs after the copolymer has dissolved.

In a preferred embodiment, the at least one surfactant (B) is added to the water used in the preparation of the formulation prior to the addition of the at least one copolymer (A).

In a further preferred embodiment, the at least one surfactant (B) is added to the water used in the preparation of the formulation after the addition of the at least one copolymer (A).

In a further preferred embodiment, the addition of the at least one surfactant (B) and the at least one copolymer (A) to the water used in the preparation of the formulation takes place simultaneously. The water used in the preparation of the formulation is preferably water containing fresh water or salts, for example seawater or promoted formation water.

In addition to water, small amounts of water-miscible, organic solvent mittein, for example, water-miscible alcohols may be present. If present at all, however, their amount should be less than 20% by weight, based on the sum of all solvents used, preferably less than 10% by weight, more preferably less than 5% by weight, and particularly preferably no organic solvent should be additionally used , The formulation may further contain salts. These are, in particular, alkali metal salts and alkaline earth metal salts. Examples of typical cations include Na ⁺ , K ⁺ , Mg ²⁺ or Ca ²⁺ and examples of typical anions include chloride, bromide, bicarbonate, sulfate or borate. If the aqueous formulation contains salts, at least one or more alkali metal ions, in particular at least Na ⁺ , are generally present. In addition, alkaline earth metal ions may also be present, the weight ratio of alkali metal / alkaline earth metal ions generally being greater than or equal to 2, preferably greater than or equal to 3. As anions, at least one or more halide ions, in particular at least chloride, are generally present. In general, the amount of chloride is at least 50 wt .-%, preferably at least 80 wt .-% with respect to the sum of all anions. The total amount of all salts in the aqueous formulation can be up to 350,000 ppm by weight, based on the sum of all components of the formulation. However, it should preferably be not more than 200,000 ppm by weight.

In addition, the aqueous formulation may of course comprise further components. Examples of further components include bases, such as alkali metal hydroxides or sodium carbonates, complexing agents, biocides, stabilizers or inhibitors, for example corrosion inhibitors.

The concentration of the copolymer is determined so that the aqueous formulation prior to the addition of the at least one surfactant (B) has the desired viscosity for use in the petroleum-bearing formation. However, the viscosity of the formulation should in any case be at least 5 mPas (measured at 25 ° C. and a shear rate of 7 s ^-1 ), preferably at least 10 mPas. According to the invention, the concentration of the at least one copolymer (A) in the formulation is 500 to 5000 ppm, preferably 750 to 2000 ppm and for example about 1000 ppm.

According to the invention, the concentration of the at least one surfactant (B) in the formulation is at least 0.5 and less than 50.0 ppm with respect to the sum of all components of the aqueous formulation. Preferably, the amount is 0.5 to 40.0 ppm, more preferably

0.5 to 30.0 ppm, more preferably 1.0 to 20.0, more preferably 2.5 to 15.0 ppm, and most preferably 5.5 to 10.0. The amount used is varied depending on the chosen surfactant (B) and chosen so that its addition results in the desired lowering of the viscosity of the aqueous formulation.

According to the invention, the weight ratio of the at least one copolymer (A) to the at least one surfactant (B) is in the range from 10: 1 to 1000: 1, preferably from 50: 1 to 500:

1, and more preferably from 100: 1 to 200: 1. Injecting the aqueous formulation may be carried out by conventional means. The formulation can be injected by conventional pumps into one or more injection wells. The injection wells are usually lined with cemented steel tubes, and the steel tubes including the cement layer are attached to the perforated desired place. The formulation enters the petroleum formation through the perforation from the injection well. By way of the pressure applied by means of the pumps, the volumetric flow of the formulation and thus also the shear stress with which the aqueous formulation enters the formation are determined in a manner known in principle. The shear stress on entering the formation can be calculated by a person skilled in the art in a manner known in principle on the basis of the Hagen-Poiseuille law using the area through which the formation flows, the mean pore radius and the volume flow. The average porosity of the formation can be determined in a manner known in principle by measurements on cores. Naturally, the shear stress is greater the larger the volume flow of aqueous formulation injected into the formation.

The volume flow in the course of the injection and thus the shear rate can be determined by the person skilled in the art, depending on the conditions in the formation. Preferably, the shear rate is during the pressing of the aqueous formulation in the oil reservoir at least 30,000 s ^_1, Particularly preferably at least 60,000 s ^_1 and particularly preferably at least 90,000 s ^_1.

The person skilled in the art will select the copolymers to be used according to the invention, depending on the desired properties of the formulation to be injected. The copolymers and preferred copolymers have already been described initially. Particular preference is given to using copolymers which have a shear degradation of less than 10%, preferably less than 8%, for the process according to the invention.

Particularly preferred copolymers for carrying out the process include monomers (A1) of the general formula H ₂ C =CH-O- (Cn'H 2n ') - O- (CH ₂ -CH ₂ -O) k - (CH ₂ -CH (R ⁴ ) -O) iH (Ia1), where n 'is 2 to 6, preferably 2 to 4 and particularly preferably 4. R ⁴ in the preferred variant represents a hydrocarbon radical having 3 to 10 carbon atoms, in particular an n-propyl radical. Furthermore, in formula (Ia1) k is a number from 20 to 30 and I is a number from 6 to 20, preferably 8 to 18. The amount of the monomers (A1) of the formula (Ia1) is 0.2 to 5 wt. -%, preferably 0.5 to 2 wt .-%. As monomer (A2a) the preferred copolymer comprises 40 to 60% by weight of acrylamide and as monomer (A2b) 35 to 55% by weight of a sulfonic acid group-containing monomer (A2b), preferably 2-acrylamido-2-methylpropanesulfonic acid or salts from that.

Copolymers which are furthermore preferred for carrying out the process likewise comprise 0.2 to 5% by weight, preferably 0.5 to 2% by weight, of monomers (A1) of the general formula (Ia1) and 30 to 40% by weight of acrylamide (A2a ). They also comprise 25 to 35 wt .-% of at least one sulfonic acid group-containing monomer (A2b), preferably 2-acrylamido-2-methylpropanesulfonic acid or salts thereof and 25 to 35 wt .-% of at least one cationic ammonium ion-containing monomer, preferably salts of 3-trimethylammoniumpropyl (meth) acrylamides and 2-trimethylammoniumethyl (meth) acrylates.

The following examples are intended to illustrate the invention in more detail: Example 1: Preparation of hydrophobically associating copolymer C1

The preparation was carried out according to WO 201 1/015520, Example 3.

 In a 3L vessel with stirrer and thermometer were 242.5 g of a 50% Na-AMPS solution. (Acrylamido-2-methylpropanesulfonic acid Na salt, AMPS 2405, Fa. Lubrizol) submitted. With stirring, 295.8 g of water were added. Subsequently, 1, 2 g of Surfynol DF 58 (silicone defoamers from Air Products) and 0.4 g of Baysilone EN (silicone defoamer from Bayer) were added in succession as defoamers. After addition of 4.6 g Pluriol A1 190V + 12PeO (development product from BASF consisting of hydroxybutyl vinyl ether with 25 ethylene oxide units and 12 Pentenoxideinheiten) were 228.8 g of a 50% ac- rylamid sol. (Cytec) and 4.8 g Lutensol T015 added (Ci3-oxo-alcohol ethoxylate + 15 ethylene oxide units).

After adding 2.4 g of a 5% solution of Versenex. (Chelating agent from Dow) for destabilization of the acrylamide sol. the pH was adjusted with a 20% NaOH solution and / or 20% H2S04 solution. set to 6.0. During the inertization by flushing with nitrogen for 30 minutes, the solution was cooled to about 20 ° C. The solution was then transferred to a plastic container of dimensions (b ^* t ^* h) 15cm ^* 10cm ^* 20cm and 16.0g (200ppm) of 10% 2,2'-azobis (2-amidinopropane ) dihydrochloride, 0.5 g (10 ppm) of 1% strength bisulfite solution, 8 g (6 ppm) of 0.1% tert-butyl hydroperoxide solution and 4.0 g (5 ppm) of 1% strength iron (II) sulfate solution.

The polymerization was started by irradiation with UV light (two Philips tubes, Cleo Performance 40 W). The cut-resistant gel was 3 h removed from the plastic container and cut with scissors in 5 cm ^* 5 cm ^* 5 cm gel cubes - after approx. 2 Before the gel cubes were crushed by means of a conventional meat grinder, they were coated with the release agent Sitren 595 (polydimethylsiloxane emulsion, Goldschmidt). The release agent is a polydimethylsiloxane emulsion which has been diluted 1:20 with water. The resulting gel granules were then evenly distributed on a dry grid and dried in a circulating air dryer at about 90-120 ° C in vacuo to constant weight. There were obtained about 500 g of a white, hard granules, which was converted by means of a centrifugal mill into a powdery state. Example 2: Viscosity measurement with addition of nonionic surfactants

a) An aqueous solution of hydrophobic associative copolymer C1 at the concentration of 1000 ppm was mixed with various surfactants in concentrations of 0.5 to 6.5 ppm. Subsequently, the viscosity of this solution was measured, the initial viscosity without surfactant was 35 mPas. The results are summarized in the following table: Table 1: Viscosity of the formulations [mPas] at 20 ° C and a shear rate of 7 s ^_1 depending on the surfactant and the amount used

¹ > Lutensol TO x = saturated C13 oxo alcohol ethoxylate with x ethylene oxide units

 2> Lutensol FSA 10 = oleic amide ethoxylate with 10 ethylene oxide units

As can be seen from Table 1, even the addition of 0.5 ppm of a nonionic surfactant according to the invention can lead to a significant reduction in the viscosity of the solution of the hydrophobically associating copolymer.

It has also been found that the added amount of surfactant has a decisive influence on the viscosity of the polymer solution. For some of the surfactants evaluated, an increase in viscosity is initially observed, which, however, is followed by a decrease in the viscosity upon further addition of the surfactant.

However, it can be seen from the example of Lutensol TO 6 (V6) and in particular Lutensol TO 5 (V7, Example 2b) that not every surfactant results in a reduction in viscosity, but that the addition of a surfactant can also lead to an undesirable increase in viscosity. b) An aqueous solution of the hydrophobic associative copolymer C1 at the concentration of 1000 ppm was mixed with Lutensol TO 5 in concentrations of 0.5 to 100 ppm. Subsequently, the viscosity of this solution was measured, the initial viscosity without surfactant was 35 mPas. The results are summarized in Table 2: Table 2: Viscosity of the formulations at 20 ° C and a shear rate of 7 s ^_1 with addition of Lutensol TO 5 as a function of the amount of surfactant used

Wie aus Tabelle 2 ersichtlich wird, erhöht sich die Viskosität auch bei der Zugabe von großen Mengen Lutensol TO 5. c) Eine Zugabe von 5 ppm Natriumdodecylsulfonat zu einer wässrigen Lösung des hydrophob assoziativen Copolymers C1 mit der Konzentration von 1000 ppm führte bei 20°C und einer Scherrate von 7 s^_1 zu einer Viskositätserniedrigung von 35 mPas auf 23 mPas und eine Zugabe von 10 ppm Tensid zu einer weiteren Viskositätsverringerung auf 20 mPas.

As can be seen from Table 2, the viscosity also increases with the addition of large amounts of Lutensol TO5. C) Addition of 5 ppm of sodium dodecylsulfonate to an aqueous solution of hydrophobic associative C1 copolymer of 1000 ppm concentration was carried out at 20 ° C and a shear rate of 7 s- ¹ to a viscosity reduction of 35 mPas to 23 mPas and an addition of 10 ppm of surfactant to a further reduction in viscosity to 20 mPas.

3. adsorption measurement

To measure the adsorption, the ground quartz rock MICROSIL M 500 (> 99% by weight S1O2) from Euroquarz with a particle size of 1-15 μm and a surface area of 2.66 m ² / g was used. The surface of the rock was determined by BET. Subsequently, 1, 4 g of the ground rock were suspended in 100 g of a 0.02% surfactant or polymer solution. The quartz suspension was mixed in a 250 ml screw-top jar at 20 ° C for 48 hours on the roller board. Thereafter, the sand was centrifuged off the liquid and the remaining Tensid- or polymer content of the solution determined by HPLC quantitatively. This value is then compared with the original surfactant or polymer content in the solution and the adsorption is calculated from the difference.

The adsorption of the hydrophobically associating copolymer C1 and the surfactants Lutensol TO10, Lutensol TO 5 and Lutensol FSA 10 was investigated. The results are shown in Table 3.

Table 3: Adsorption measurements on quartz rock

adsorption

Hydrophobic associating copolymer C1 <0.1 mg / m ²

Lutensol TO 10 2.3 mg / m ²

Lutensol FSA 10 2.4 mg / m ²

Lutensol TO 5 8.0 mg / m ² It has been found that the hydrophobically associating copolymer has no significant adsorption on the rock surface. Lutensol TO 10, Lutensol TO 5 and Lutensol FSA 10 on the other hand show strong adsorption. Despite the strong adsorption of Lutensol TO 5, this surfactant is not suitable for the process according to the invention because of its viscosity-increasing behavior (see Example 2b, Table 2). The surfactants Lutensol TO 10 and Lutensol FSA 10 according to the invention, on the other hand, have not only favorable adsorption values but also the desired viscosity-reducing behavior (Example 2a, Table 1).

Claims

claims Process for the extraction of crude oil, in which an aqueous formulation is injected through at least one injection well into a crude oil deposit and the deposit is withdrawn through at least one production well crude oil, characterized in that the aqueous formulation a) 500 to 5000 ppm of at least one water-soluble, hydrophobically associating copolymer ( A), available from the implementation of 0.1 to 15.0% by weight of at least one monoethylenically unsaturated hydrophobically associating monomer (A1), wherein the at least one monoethylenically unsaturated hydrophobically associating monomer (A1) is a monomer according to one of the formulas selected from H ₂ C = C (R ¹ ) -R ² -O- (CH ₂ -CH (R ³ ) -O) k- (CH ₂ -CH (R ⁴ ) -O) i R ⁵ (I), H ₂ C = C (R ¹ ) -O- (CH ₂ -CH ₂ (R ³ ) -O) k R ⁶ (II), H ₂ C = C (R ¹ ) - (C = O) -O- (CH ₂ -CH (R ³ ) -O) k R ⁶ (III), and H ₂ C = C (R ¹ ) -R ² -O- (CH ₂ -CH (R ³ ) -O) _k - (CH ₂ -CH (R ⁴ ) -O) i - [(CH ₂ -CH ( R ⁴ ) -0) _h (CH ₂ -CH ₂ -

where the units - (CH ₂ -CH (R ³ ) -O) _k and - (CH ₂ -CH (R ⁴ ) -O) i and, if appropriate, - [(CH ₂ -CH (R ⁴ ) -O) h- (CH ₂ -CH ₂ -O) i] are arranged in block structure in the order shown in formula (I) or formula (IV), and the radicals and indices have the following meaning:  k: is a number from 10 to 50;  I: is a number from 5 to 25;  h: is a number from 0 to 2;  i: is a number from 1 to 15; R ¹ : is H or methyl; R ² : is a single bond or a divalent linking group selected from the group consisting of - (C _n H _2n ) -, -O- (Ο _η Ή _2η ') - and -C (O) -O- (Cn "H _2n ") -, where n, n 'and n "are each a natural number from 1 to 6; each R ³ : is independently H, methyl or ethyl, provided that at least 50 mole% of R ³ is H; each R ^4: is independently a hydrocarbon radical of at least 2 Carbon atoms or an ether group of the general formula - CH 2 -OR ^{4 '} wherein R ^{4' is} a hydrocarbyl radical having at least 2 carbon atoms, provided that R ^{4 is} a hydrocarbyl radical having at least 3 carbon atoms when R ^{3 is} ethyl; R ⁵ : is H or a hydrocarbon radical having 1 to 30 carbon atoms; R ⁶ : is an aliphatic and / or aromatic, linear or branched Hydrocarbon radical having 8 to 40 carbon atoms; and a2) from 85.0 to 99.9% by weight of at least one hydrophilic monomer (A2) other than monomer (A1), at least one of the monomers (A2) being a neutral, monoethylenically unsaturated hydrophilic monomer (A2a) selected from the group consisting of (meth) acrylamide, N-methyl (meth) acrylamide, N, N'-dimethyl (meth) acrylamide and N-methylol (meth) acrylamide; wherein the amounts of the monomers (A1) and (A2) are each based on the total amount of all monomers used in the reaction, and wherein the copolymer (A) has a weight-average molecular weight M _w of 1 x 10 ⁶ to 30 x 10 ⁶ g / mol having; and b) at least 0.5 and less than 50.0 ppm of at least one surfactant (B), wherein the at least one surfactant (B) is selected from the group consisting of nonionic surfactants (B1) having an HLB value of more than 1 1, anionic surfactants (B2), cationic surfactants (B3) and zwitterionic surfactants (B4), wherein the quantities of the copolymer (A) and the surfactant (B) are each based on the sum of all components of the aqueous formulation, and wherein the weight ratio of the at least one copolymer (A) to the at least one surfactant (B) is in the range of 10: 1 to 1000: 1. A method according to claim 1, characterized in that the at least one surfactant (B) has an adsorption of greater than or equal to 1 mg / m ² of the at least partially present in the oil reservoir rock surfaces. Process according to Claim 1 or 2, characterized in that the radicals and indices in the formula (I) have the following meaning:  k: is a number from 12 to 40; I: is a number from 6 to 20; R ² : is a divalent linking group -O- (Ο _η Ή2η) -, where n 'is a natural number from 2 to 4; each R ³ : is independently H or methyl, provided that at least 50 mole% of R ³ is H; each R ⁴ : is independently a hydrocarbon radical of 3 to 8 carbon atoms; R ⁵ : is H, methyl or ethyl. Process according to any one of claims 3 to 3, characterized in that the radicals and indices in the formula (I) have the following meaning:  k: is a number from 15 to 35;  I: is a number from 8 to 18; R ² : is a divalent linking group -O- (Ο _η Ή2η) -, where n 'is 4; R ³ : is H; R ⁴ : is an n-propyl radical; ^R5: H. A method according to any one of claims 1 to 4, characterized in that the at least one hydrophilic monomer (A2) comprises at least two different, monoethylenically unsaturated, hydrophilic monomers (A2a) and (A2b), wherein (A2a) as defined in claim 1; and (A2b) at least one anionic, monoethylenically unsaturated hydrophilic monomer (A2b) which contains at least one acidic group selected from the group consisting of -COOH, -SO3H or -PO3H2. Method according to one of claims 1 to 5, characterized in that (A2a) as defined in claim 1; and (A2b) at least one anionic, monoethylenically unsaturated hydrophilic monomer (A2b) containing at least one SOsH group is. Method according to one of claims 1 to 6, characterized in that the at least one surfactant (B) is a nonionic surfactant (B1 a) according to formula (V) R ⁱ⁵ _o- (CH ₂ -CH ₂ -0) _m -H (V) where the radicals and indices have the following meanings: R ¹⁵ : is an acyclic, saturated, branched hydrocarbon radical having 5 to 25 carbon atoms;  m: is a number from 7 to 20. Method according to one of claims 1 to 6, characterized in that the at least one surfactant (B) is a nonionic surfactant (B1 b) according to formula (VI) R ^{16 is} _C (o) -NH- (CH ₂ -CH ₂ -O) oH (VI), where the radicals and indices have the following meanings: R ¹⁶ : is an aliphatic, branched or unbranched, unsaturated hydrocarbon radical having 10 to 30 carbon atoms;  o: is a number from 7 to 15. Process according to one of Claims 1 to 6, characterized in that the at least one surfactant (B) is an anionic surfactant (B2a) of the general formula (VII) R ^{7 is} -X-M1 ⁺ (VII); where the radicals have the following meaning: R ¹⁷ : is a saturated or unsaturated, aliphatic and / or aromatic, linear or branched hydrocarbon radical having 8 to 40 carbon atoms; X- is -SO ₃ -, -O-SO ₃ -, -CO ² -, -PO 3 ² - or -O-PO ₃ -; M1 ⁺ : is a cation. 0. The method according to any one of claims 1 to 6, characterized in that the at least one surfactant (B) an anionic surfactant (B2b) of the general formula (VIII) Is (CH ₂ -CH (R ⁹⁾ -0) pYZ- M2 ⁺ (VIII) - Ri8_ _0; where the radicals and indices have the following meaning: R ¹⁸ : is a saturated or unsaturated, aliphatic and / or aromatic, linear or branched hydrocarbon radical having 8 to 40 carbon atoms; R ¹⁹ : is independently H, methyl or ethyl, provided that at least 50 mol% of R ¹⁹ is H;  p: is a number from 0.1 to 30;  Y: is a single bond or a divalent linking one Group - (Cfhta) -, wherein f is a natural number from 1 to 5; Z- is -SO ³ -, -CH ² CO ² - or -PO 3 ² -; M2 ⁺ : is a cation. A method according to any one of claims 1 to 10, characterized in that in the reaction of the at least one monoethylenically unsaturated hydrophobic associating monomer (A1) with the at least one hydrophilic monomer (A2) other than monomer (A1) prior to the initiation of the polymerization reaction at least one further non-polymerizable surface-active compound (O) is used. A method according to any one of claims 1 to 1 1, characterized in that the shear rate when pressing the aqueous formulation into the Erdöllagerstätte is at least 30000 s- ¹ . A method according to any one of claims 1 to 12, characterized in that in the preparation of the aqueous formulation, the water is introduced and the copolymer is interspersed as a powder and mixed with the water, wherein the addition of the at least one surfactant (B) before the addition of the Copolymers, simultaneously or subsequently. Aqueous formulation as described in any one of claims 1 to 13. Use of an aqueous formulation according to claim 14 in tertiary mineral oil production.