DE102006049804A1 - Preparing water-soluble block alkoxylates of unsaturated carboxylic acids, for use as emulsion stabilizing comonomers, by reacting acid successively with propylene and ethylene oxides - Google Patents

Abstract

Production of water-soluble block alkoxylates (I) of alpha ,beta -ethylenically unsaturated mono- or dicarboxylic acids involves (a) propoxylating the acid (II) (or its derivative) with 1-4 mol propylene oxide per carboxy group and (b) further alkoxylating with ethylene oxide (EO) (or alkylene oxide mixture containing at least 70 mol. % EO) to give (I) of cloud point (DIN 53917) at least 75[deg] C. The reactions are effected using double metal cyanide (DMC) catalysts.

Description

The The present invention relates to a process for the preparation of water-soluble Ω-hydroxy-polyalkylene glycol block copolymers, the α-constant one unsaturated, have conjugated ester group, in particular of Ω-hydroxy-methacryloyl or Ω-hydroxy-α-acryloyl-polyalkylene glycol block copolymers and their use as copolymerizable macromonomers for emulsification, Dispersion and steric stabilization of polymers in aqueous Systems.

Polyalkylene glycols are usually industrially produced by anionic, alkali-catalyzed, ring-opening polymerization of epoxides (ethylene oxide, propylene oxide, butylene oxide) under high pressure and high temperature (see Ullmann Encyclopedia of Industrial Chemistry 5th ed VCH, ISBN 3-527-20100-9). With alcohols R'-OH as initiator, such as with methanol, arise so very specific according to equation 1 α-methoxy-Ω-hydroxy-polyalkylene glycols

With carboxylic acids as initiator finds a similar one Reaction according to equation 2 instead.

The However, resulting esters are subject to alkaline reaction medium one parallel to the ring-opening Polymerization ongoing permanent hydrolysis and transesterification reaction according to equation 3, resulting in a product mixture of α-Ω-dihydroxy-polyalkylene glycols, α-Ω-di-esters and the target product (compound 1).

Polyalkylene glycol macromonomers are those polyalkylene glycols which, in addition to the polyether chain, contain a reactive, copolymerizable, terminal double bond. They are used for the production of so-called comb polymers with polyalkylene glycol side groups ( DE-A-100 17 667 ) or as reactive emulsifiers in the emulsion polymerization ( EP-A-1 531 933 ) used. However, the Ω-hydroxy-α-allyloxy or Ω-hydroxy-α-vinyloxy-functional polyalkylene glycol macromonomers described there have the disadvantage that they can not be used as hydroxy-functional macromonomers due to the unfavorable tendency to copolymerize with many common comonomers. More generally usable and thus substantially more advantageous are Ω-hydroxy-functional polyalkylene glycol macromonomers which have in the α-position the ester group of a conjugated unsaturated acid, in particular Ω-hydroxy-functional-α-methacryloyl or α-acryloyl-polyalkylene glycol macromonomers. Conjugated unsaturated carboxylic acids and esters are understood as meaning compounds having a C =C double bond in the α, β position to the carbon atom of the carbonyl group, which therefore contain the following structural element:

The Preparation of such Ω-hydroxy-functional Polyalkylene glycol macromonomers in pure form, in the α, β position but have the ester of a conjugated unsaturated acid two reasons difficult.

First, due to the transesterification reaction described in Equation 3, those are macro monomeric pure not directly accessible by anionic, alkaline catalyzed, ring-opening polymerization of epoxides. Therefore, various attempts have been made with non-alkaline catalysts to prepare polyalkylene glycol ester macromonomers (Compound 1). In particular, chromium and tin salts ( JP-2006-070147 . JP-2003 073331 , CAS AN 103: 215878), boron trifluoride ( U.S. 3,689,532 ) and ZnCo complexes ( U.S. 6,034,208 ) as catalysts in order to prepare in front of all polyalkylene glycol macromonomers starting from unsaturated carboxylic acids such as methacrylic acid, acrylic acid or maleic acid ( JP-2006-070147 ). However, either only low molar masses could be achieved or else the products contained a high proportion of crosslinking di-ester due to transesterification reactions taking place in accordance with Equation 3 (US Pat. Ali, Stover, Macromolecules pp. 5219 ff, Vol 37, 2004 ).

Secondly, derivatives of conjugated unsaturated acids, especially the acrylic and methacrylic acid derivatives, have a high propensity for homopolymerization, so that the reactions with the alkylene oxides can only be carried out in the presence of high concentrations of polymerization inhibitors ( JP-63284146 . JP-2005-281274 ). The prior art uses phenolic or aminic polymerization inhibitors, for example hydroquinone, methylhydroquinone, tert-butylhydroquinone, benzoquinone, BHA, p-phenylenediamine or phenothiazine. These inhibitors react by their active OH or NH end groups in turn with the epoxides to other unwanted by-products. Often, their inhibitory action is also insufficient to completely prevent the polymerization of the conjugated unsaturated acid / ester group. Therefore, in reactions with alkylene oxides, macromonomers contaminated with high molecular weight polymers formed by polymerization on the conjugated unsaturated acid group are obtained. Such high polymer impurities can be recognized by means of gel permeation chromatography (GPC) as components having molar masses greater than 20,000 g / mol.

EP-A-1 012 203 describes the reaction of propylene oxide and mixtures of propylene oxide and ethylene oxide with conjugated unsaturated carboxylic acids and hydroxy esters in the presence of so-called DMC catalysts (DMC double metal cyanide catalysts).

The use of the DMC catalysts avoids the disadvantages of Equation 3, since the reaction does not proceed in alkaline medium and thus the hydrolysis of the resulting esters is not catalyzed. However, DMC catalysts are industrially used exclusively for the polymerization of propylene oxide or propylene oxide-rich alkylene oxide mixtures with more than 50 mol% of propylene oxide, so that generally only water-insoluble or poorly water-soluble polyalkylene glycols can be prepared ( EP-0 992 523 A1 ). To produce polyalkylene glycol macromonomers having good emulsification and stabilization properties, they must have good water solubility. This is achieved by the proportion of ethylene oxide monomer units being at least 70 mol%, ideally at least 80 mol%. The high proportion of ethylene oxide units causes a high cloud point of at least 75 ° C, determined in 1% aqueous solution according to DIN 53917, and thus good water solubility. EP-A-1 012 203 on the other hand, it describes only α-methacryloyl or α-acryloyl macromonomers prepared with pure propylene oxide monomer units or with a random mixture of ethylene oxide and propylene oxide monomer units containing less than 50 mole% of ethylene oxide. Such macromonomers have too low cloud points, that is, too low water solubility, in order to achieve sufficient dispersing and emulsifying properties in aqueous solutions. The production of purely ethylene oxide-based macromonomers or the preparation of block copolymers with a predominant proportion of ethylene oxide succeeds EP-A-1 012 203 Not.

Another method to produce α-methacryloyl or α-acryloyl-Polyalkylenglykolmakromonomere is therefore the more complex, two-stage process, first α-methoxy-Ω-hydroxy-polyalkylene glycols (M-PEGs) and produce them by esterification with acrylic acid or methacrylic acid in the α -Methoxy-Ω-methacryloyl-polyalkylene glycol ester ( WO-A-00/012 577 . EP-A-0 965 605 ) (equation 4)

However, these α-methoxy-Ω-methacryloyl-polyalkylene glycol macromonomers no longer contain any free hydroxyl groups, and therefore also have less favorable water solubility and poorer emulsifying properties and are due to the terminal non-reactive Ω-methoxy group no further reactions more accessible.

task The present invention was therefore a method of preparation of readily water-soluble Ω-hydroxyl-functional Polyalkylene glycol macromonomers, in the α-position, the structural unit of a conjugated, unsaturated Carbonsäureesters wear, in particular of highly water-soluble Ω-hydroxy-α-methacryloyl or Ω-hydroxy-α-acryloyl-polyalkylene glycols in which not the hydrolysis and transesterification according to equation 3 takes place, so that pure linear Ω-hydroxy-α- (meth) acryloyl-polyalkylene glycols with an ethylene oxide content of at least 70 mol% arise. Especially It was an object of the present invention, readily water-soluble linear Ω-hydroxy-α- (meth) acryloyl-Polyalkylenglykolblockcopolymere with long polyethylene oxide blocks to produce in this way.

It was surprisingly found that, in contrast to the descriptions in EP-A-1 012 203 and EP-A-0 992 523 the preparation of readily water-soluble Ω-hydroxy-α-methacryloyl or Ω-hydroxy-α-acryloyl-polyalkylene glycol macromonomers with DMC catalysts is possible. In the preparation of macromonomers having an ethylene oxide content of more than 70 mol% in the presence of a DMC catalyst and of polymerization inhibitors, one starts from conjugated unsaturated acids or conjugated unsaturated hydroxyalkyl esters. The polymerization of the alkylene oxide takes place in two stages, resulting in block copolymers. In the first step, the conjugated unsaturated acids or conjugated hydroxyalkyl esters are reacted in the presence of DMC catalyst and polymerization inhibitor with one to four units of propylene oxide, followed by polymerizing a polyether block having a high ethylene oxide content. As a result, based on the macromonomer molecule, the proportion of polyethylene oxide groups can be increased to more than 70 mol% and thus the water solubility and the cloud point of the macromonomers can be increased.

object The invention thus provides a process for the production of water-soluble Block alkoxylates α, β-ethylenic unsaturated Mono- or dicarboxylic acids, by the α, β-ethylenic unsaturated Mono- or dicarboxylic acid or an alkoxylatable derivative thereof first with 1 to 4 moles of propylene oxide per carboxylic acid group is alkoxylated, and after this propoxylation a further alkoxylation with ethylene oxide or a mixture of alkylene oxides which is at least Contains 70 mol% of ethylene oxide, carried out is, so that according to DIN 53917 certain cloud point of the resulting block alkoxylate at least at 75 ° C wherein the alkoxylations in the presence of DMC catalysts respectively.

object The invention is preferably a method for producing the Compounds of the formulas 2, 3, 4 or 5. The preferred process according to the invention comprises a two-step reaction of the corresponding conjugated α, β-ethylenically unsaturated acids or conjugated α, β-ethylenic unsaturated Hydroxyalkyl esters or hydroxyalkylethoxy and hydroxyalkylpropoxy esters with first 1 to 4 moles of propylene oxide in stage 1 and then ethylene oxide or a mixture of at least 70 mole percent ethylene oxide and propylene oxide in stage 2 catalyzed by a DMC catalyst.

Farther preferably, work is carried out in the presence of polymerization inhibitors.

worin
k für eine Zahl von 1 bis 4,
n für eine Zahl von 1 bis 3,
R, R¹ unabhängig voneinander für H oder Methyl,
A für C₂- bis C₃-Alkylen, mit mindestens 70 mol-% C₂-Alkylen, und
m für eine Zahl von 7 bis 500 stehen.The compounds of formulas 2, 3, 4 and 5 are

wherein
k for a number from 1 to 4,
n is a number from 1 to 3,
R, R ¹ independently of one another are H or methyl,
A is C ₂ - to C ₃ -alkylene, with at least 70 mol% of C ₂ -alkylene, and
m stands for a number from 7 to 500.

(AO) _n may stand for pure polyethylene oxide groups or polyethylene oxide-propylene oxide groups in random arrangement with at least 70 mol% of ethylene oxide.

reactive Derivatives of α, β-ethylenic unsaturated carboxylic acids are in particular their esters, especially their hydroxyalkyl esters.

suitable conjugated, α, β-unsaturated acids especially acrylic acid, methacrylic acid, fumaric acid, maleic acid, Itaconic acid. Suitable conjugated, unsaturated Hydroxyalkyl esters or hydroxyalkylethoxy and hydroxyalkylpropoxy esters are in particular hydroxyethyl methacrylate, hydroxypropyl methacrylate, Hydroxyethyl acrylate, hydroxypropyl acrylate, diethylene glycol monomethacrylate, Diethylene monoacrylsäureester, Dipropylene monomethacrylic, Dipropylene monoacrylsäureester, Triethylene monomethacrylic, Triethylene monoacrylsäureester, Tripropylene monomethacrylic, Tripropylene monoacrylsäureester.

When Polymerization inhibitors can 2,2,6,6-tetramethylpiperidine-1-oxyl or 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl or other known polymerization inhibitors are used, the formation of high polymers by polymerization of the conjugated unsaturated Acid / Estergruppe in the starting materials and the copolymerizable macromonomers during their Production by addition of alkylene oxides in technically interesting Reaction temperatures of 80-130 ° C effective prevent.

The inventive reaction of the conjugated unsaturated acids or reactive derivatives such as conjugated unsaturated hydroxyalkyl esters with alkylene oxides must be carried out in the presence of so-called DMC catalysts (double metal cyanide catalysts). These catalysts have, for example, the general formula Zn ₃ [Co (CN) ₆ ] ₂ .xZnCl ₂ .yH ₂ O.zGlyme with x = 0.2 to 3, y = 1 to 10 and z = 0.5 to 10, as in EP-B-0 555 053 disclosed. Suitable DMC catalysts are also known in the literature with other complexing ligands. Their production and composition will include in EP-A-1 244 519 . EP-A-0 761 708 . EP-A-654 302 and EP-A-1 276 563 described. In particular, those in Example 2 of EP-A-1 276 563 described DMC catalysts suitable.

The alkylene oxides are metered in a two-stage manner to obtain di- or triblock copolymers with different statistical distribution of the alkylene oxide units in the blocks. All block copolymers have in common that directly on the conjugated α, β-ethylenically unsaturated carboxylic acid or the conjugated α, β-ethylenically unsaturated hydroxyalkyl ester or hydroxyalkylethoxy or hydroxyalkylpropoxy ester is first added 1 to 4 moles of propylene oxide, and then a block ethylene oxide units or randomly mixed Alkylene oxide units having an ethylene oxide content of at least 70 mol% follows. The reaction of the conjugated α, β-ethylenically unsaturated carboxylic acid or its reactive derivatives and the alkylene oxides, if appropriate in the presence of polymerization inhibitors, takes place under the customary reaction onsbedingungen a technical, DMC-catalyzed alkoxylation, ie in the temperature range 80-150 ° C preferably 100-130 ° C and pressures between 2 and 20 bar under nitrogen, optionally in the presence of inert, aprotic solvents such as toluene, xylene or THF.

critical for the Production of high quality water soluble macromonomers is in the inventive method the alkoxylation with 1 to 4 moles of propylene oxide per mole of α, β-ethylenic unsaturated carboxylic acid or their reactive derivatives before the subsequent alkoxylation with ethylene oxide or a mixture of alkylene oxides with at least 70 mol% of ethylene oxide.

The Molar mass of the reaction products according to the invention such as Ω-hydroxy-α-methacryloyl or Ω-hydroxy-α-acryloyl-polyalkylene glycol macromonomers or mixtures thereof with the polymerization inhibitors can by means of Determination of the OH number (according to DIN 53240 Determination of the number average Mn) and by GPC analysis with PEG calibration (determination of the molecular weight distribution) be determined. The molecular weight is generally between 500 and 10,000 g / mol, preferably between 750 and 7000 g / mol. The ratio conjugates unsaturated carboxylic acid to propylene oxide, ethylene oxide units and hydroxyl end groups in the Macromonomer can be determined by NMR spectroscopy be determined. The water solubility the reaction products according to the invention can by determining the cloud point according to DIN 53917 in 1% aqueous Solution determined become.

The obtained according to the invention water-soluble Reaction products, in particular those of the formulas 2, 3, 4 or 5, can with a variety of radically polymerizable monomers such as For example, styrene, vinyl acetate, acrylic acid, methacrylic acid and their alkyl esters in substance and aqueous solution by using common initiators the radical polymerization are copolymerized. The resulting comb polymers with polyalkylene side chains are through the polyalkylene glycol side chains sterically stabilized and thus form stable aqueous polymer dispersions.

The Invention and applications thereof will now be further described by way of examples explained become.

Example 1:

In a 1 liter pressure reactor, 0.625 mol (90 g) of hydroxypropyl methacrylate and 0.045 g of 2,2,6,6-tetramethylpiperidine-1-oxyl and 0.045 g of the in EP-A-1 276 563 submitted described DMC catalyst. The mixture is heated to a temperature of 110 ° C. under nitrogen and, at a pressure of about 3 bar, an amount of 72.5 g of propylene oxide is metered in so that the resulting heat of reaction can be removed. After the reaction of the propylene oxide visible from the pressure drop 560 g of ethylene oxide is metered again so that the resulting heat of reaction can be dissipated. After Abreaktion recognizable by the pressure drop to the outlet pressure, the product by OH number titration, NMR spectroscopy and GPC molecular weight determination is analyzed. OH number in mg KOH / g according to DIN 53240 Calculated molecular weight Mn from OH number in g / mol NMR molar ratio of ¹ H NMR signals double bond methacryl: PO: EO: CH ₂ OH GPC characterization (lipophilic GPC in THF with PEG calibration standards 50.6 1109 1: 2.9: 20: 1.07 a main peak> 92% with maximum at 1100 g / mol no polymer components with molar masses above 2500 g / mol

Thus, a methacrylic acid ester (PO) ₃ (EO) ₂₀ -OH block copolymer has been formed.

Of the cloud point according to DIN 53917 in 1% aqueous solution was more than 95 ° C

Example 2:

In a 1 liter pressure reactor, 0.625 mol (90 g) of hydroxypropyl methacrylate and 0.045 g of 2,2,6,6-tetramethylpiperidine-1-oxyl and 0.045 g of the in EP-A-1 276 563 submitted described DMC catalyst. The mixture is heated under nitrogen to a temperature of 120 ° C and metered at a pressure of about 3 bar, an amount of 72.5 g of propylene oxide so that the heat of reaction can be removed. After the reaction of the propylene oxide recognizable by the pressure drop, 560 g of ethylene oxide will do so again Siert that the resulting heat of reaction can be dissipated. After Abreaktion recognizable by the pressure drop to the outlet pressure, the product by OH number titration, NMR spectroscopy and GPC molecular weight determination is analyzed. OH number in mg KOH / g according to DIN 53240 Calculated molecular weight Mn from OH number in g / mol NMR molar ratio of ¹ H NMR signals double bond methacryl: PO: EO: CH ₂ OH GPC characterization (lipophilic GPC in THF with PEG calibration 50.6 1109 1: 2.9: 20: 1.07 a main peak> 92% with maximum at 1100 g / mol no polymer components with molar masses above 2500 g / mol

Thus, a methacrylic acid ester (PO) ₃ (EO) ₂₀ -OH block copolymer was formed. High-polymer fractions with molar masses> 10000 g / mol, as would be produced by polymerization of the conjugated double bond of the methacrylic acid group, are absent.

Of the cloud point according to DIN 53917 in 1% aqueous solution was more than 95 ° C

Example 3:

In a 3 l pressure reactor, 1 mol (144 g) of hydroxypropyl methacrylate and 0.05 g of 2,2,6,6-tetramethylpiperidine-1-oxyl and 0.15 g of the in EP-A-1 276 563 submitted described DMC catalyst. The mixture is heated under nitrogen to a temperature of 100 ° C and at a pressure of about 3 bar, an amount of 58 g of propylene oxide so metered that the resulting heat of reaction can be dissipated. After the reaction of the propylene oxide recognizable by the pressure drop, 1994 g of ethylene oxide is again metered so that the resulting heat of reaction can be removed. After Abreaktion recognizable by the pressure drop to the outlet pressure, the product by OH number titration, NMR spectroscopy and GPC molecular weight determination is analyzed. OH number in mg KOH / g according to DIN 53240 Calculated molecular weight Mn from OH number in g / mol NMR molar ratio of ¹ H NMR signals double bond methacryl: PC: EO: CH ₂ OH GPC characterization (lipophilic GPC in THF with PEG calibration 28.8 1947 1: 2.1: 37: 1.15 a main peak> 90% with maximum at approx. 1700 g / mol no polymer components with molecular weights above 3000 g / mol

Thus, a methacrylic acid ester (PO) ₂ (EO) ₃₇ -OH block copolymer was formed. High-polymer fractions with molar masses> 10000 g / mol, as would be produced by polymerization of the conjugated double bond of the methacrylic acid group, are absent

Of the cloud point according to DIN 53917 in 1% aqueous solution was more than 95 ° C.

Example 4:

The Macromonomer from Example 1 is used as coemulsifier in the emulsion polymerization of n-butyl acrylate, methyl methacrylate and methacrylic acid in aqueous Fleet used. The in situ forming copolymer of butyl acrylate, Methyl methacrylate, methacrylic acid and the product of Example 1 has good emulsion stabilizing Properties.

500 ml of deionized water are placed in a glass flask and 15 g of sodium alkyl sulfate, 15 g of 3.75% ammonium peroxodisulfate, 11.5 g of n-butyl acrylate, 11.8 g of methyl methacrylate and 0.48 g of methacrylic acid, stirred and stirred under nitrogen to 80 ° C heated. Over a period of 4 hours, a monomer emulsion is metered in under nitrogen consisting of 470 ml of water, 16 g of sodium alkylsulfonate, 8 g of the product of Example 1, 440 g of n-butyl acrylate, 440 g of methyl methacrylate, 8.8 g of methacrylic acid and 2.85 G Ammonium peroxodisulfate exists. After complete dosing of the monomer emulsion and post-polymerization of one hour at 80 ° C, the polymer dispersion is cooled and adjusted to a neutral pH.

The in situ forming copolymer of butyl acrylate, methyl methacrylate, methacrylic acid and the product of Example 1 is a stable aqueous polymer dispersion.

Example 5:

The Macromonomer from Example 2 is used as coemulsifier in the emulsion polymerization a styrene / acrylate dispersion used. For this purpose, a monomer solution (1) from 332 g of deionized water, 4.8 g of sodium alkyl sulfate, 15 g of the product of Example 2, 3.6 g of sodium bicarbonate, 216 g of styrene, 300 g of n-butyl acrylate, 144 g of methyl acrylate and 6.6 g of methacrylic acid. Likewise, an initiator solution (2) from 3.33 g of ammonium peroxodisulfate and 85.5 ml of deionized Water produced.

204 g of deionized water is placed in a 2 liter reaction vessel, 6.6 g of the product from Example 2 are added. Under nitrogen atmosphere and stirring the mixture at 80 ° C heated, then 22 ml of the initiator solution (2) and 25 ml of the monomer solution are added and so the emulsion polymerization started. At a reaction temperature from 80 ° C be under cooling the remaining monomer solution (1) and the initiator solution (2) dosed within 3 hours. Then another hour heated and the product is neutralized to pH 6 to 8.

It A stable polymer dispersion with a solids content is formed of 50%.

Claims (9)

Process for the preparation of water-soluble Block alkoxylates α, β-ethylenic unsaturated Mono- or dicarboxylic acids, by the α, β-ethylenic unsaturated Mono- or dicarboxylic acid or an alkoxylatable derivative thereof first with 1 to 4 moles of propylene oxide per carboxylic acid group is alkoxylated, and after this propoxylation a further alkoxylation with ethylene oxide or a mixture of alkylene oxides which is at least Contains 70 mol% of ethylene oxide, carried out is, so that according to DIN 53917 certain cloud point of the resulting block alkoxylate at least at 75 ° C wherein the alkoxylations take place in the presence of DMC catalysts. The process of claim 1 wherein the prepared water-soluble block alkoxylate is selected from compounds 2, 3, 4 or 5

where k is a number from 1 to 4, n is a number from 1 to 3, R, R ^1, independently of one another, are H or methyl, A is C ₂ - to C ₃ -alkylene, having at least 70 mol% of C ₂ - Alkylene, and m stand for a number from 7 to 500. A process as claimed in claim 1 and / or 2, wherein the conjugated α, β-unsaturated acid is acrylic acid, methacrylic acid, fumaric acid, maleic acid or itaconic be used. Process according to claim 1 and / or 2, wherein as reactive Derivative of a conjugated, α, β-unsaturated acid hydroxyethyl methacrylate, Hydroxypropyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, Diethylenglykolmonomethacrylsäureester, Diethylene monoacrylsäureester, Dipropylenglykolmonomethacrylsäureester, Dipropylene monoacrylsäureester, Triethylenglykolmonomethacrylsäureester, Triethylene monoacrylsäureester, Tripropylenglykolmonomethacrylsäureester, Tripropylene monoacrylsäureester be used. Method according to one or more of claims 1 to 4, wherein the cloud point of the resulting block alkoxylate is more than 90 ° C. Method according to one or more of claims 1 to 5, wherein 2,2,6,6-tetramethylpiperidine-1-oxyl as a polymerization inhibitor or 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl be used. Method according to one or more of claims 1 to 6, which is carried out in the temperature range of 80-150 ° C. Method according to one or more of claims 1 to 7, which at pressures between 2 and 20 bar is carried out under nitrogen. Use of according to the method according to claim 1 to 8 obtained block alkoxylates as a copolymerizable emulsifier, Additive, emulsifier or coemulsifier for emulsion stabilization in emulsion or suspension polymerizations.