EP2707116A1

EP2707116A1 - Oil-in-water emulsions

Info

Publication number: EP2707116A1
Application number: EP12719389.4A
Authority: EP
Inventors: Claudius Kormann; Wolfgang Gaschler; Christian Holtze
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2011-05-10
Filing date: 2012-05-09
Publication date: 2014-03-19
Also published as: WO2012152810A1; US9650745B2; CN103547350A; US20140107229A1

Abstract

The invention relates to oil-in-water emulsions based on fatty alcohols and mono- or diesters of glycerol and the use thereof as antifoams or deaerators for aqueous compositions. The oil phase of the emulsions according to the invention consists to at least 95% by weight of the following constituents: a) 40 to 95% by weight, based on the total weight of the oil phase, of a mixture of at least two alcohols as component A, consisting of: a1) at least one alkanol having 12 to 30 carbon atoms as component A1, a2) at least one mono- or diester of glycerol with at least one fatty acid having 14 to 24 carbon atoms as component A2; b) 0.1 to 10% by weight, based on the total weight of the oil phase, of at least one further component B, which is selected from esters of C₁₂-C₃₆-alkanecarboxylic acids with polyglycerol, amides of C₁₂-C₃₆-alkanecarboxylic acids with alkylenediamines or oligoalkyleneamines, and esters of C₁₂-C₃₆-alkanecarboxylic acids with C₁₂-C₃₆-alkanols, and mixtures thereof, c) 4.9 to 50% by weight, based on the total weight of the oil phase, of at least one further component C, which is selected from organic substances which are liquid at 50°C and 1013 mbar, at atmospheric pressure have a boiling point above 200°C, and at 25°C and 1013 mbar have a solubility in water of less than 0.1 g/l.

Description

The invention relates to oil-in-water emulsions based on fatty alcohols and mono- or diesters of glycerol and their use as defoamers or deaerators for aqueous compositions.

Many industrial processes require the handling of aqueous solutions and suspensions that tend to foam because of their ingredients. This foaming complicates the process and must therefore be kept as low as possible or even avoided. Examples of foam-forming aqueous compositions are detergent-containing compositions, saponin-containing compositions, wastewater in sewage treatment plants, protein-containing compositions such as soybean extracts, and in particular pulp suspensions, e.g. As wood pulp and / or pulp-containing suspensions, such as those used in particular in the paper industry for the production of paper, cardboard or cardboard.

In addition to the formation of foam, which is permanently replicated from coalescing air bubbles, the air trapped in these systems, which is in finely dispersed, stable form, also proves to be problematic. The reduction in the air content of these systems is therefore also of particular importance.

For these reasons, the foam-forming aqueous compositions are used in their processing and, for. T. so-called defoamers and / or deaerators already at their production, which suppress the undesirable foaming even at low concentrations, reduce the content of trapped air or destroy already formed foam. The known from the prior art defoamers are often aqueous compositions based on oil-in-water dispersions or emulsions whose oil phase at least one hydrophobic substance, such as mineral oils, silicone oils, polyalkylene oxides, their esters with fatty acids and their ethers containing long-chain alcohols, native fats and / or oils, waxes, ester waxes or long-chain alcohols. There have also been various reports of the use of distillation residues obtained by the production of long-chain alcohols by the Ziegler process or by oxo synthesis (see, for example, EP-A 149812). US Pat. No. 4,950,420 discloses defoaming agents for the paper industry comprising 10 to 90% by weight of a surface-active polyether, such as polyoxyalkylenated glycerol or polyalkoxylated sorbitol and 10 to 90% by weight of a fatty acid ester of polyhydric alcohols, such as mono- and diesters of polyethylene glycol or polypropylene glycol.

EP 0531713 and WO 94/08091 describe defoamers for the paper industry based on oil-in-water emulsions whose oil phases contain alcohols, fatty acid esters, distillation residues, hydrocarbons in combination with polyglycerol esters.

DE 2157033 describes antifoams based on aqueous emulsions which contain C 12-22 -alkanols and / or C 12-22-fatty acid esters of dihydric to trihydric alcohols and paraffin oil or C 12-22 fatty acids.

Joshi et al. put in Colloids and Surfaces A: Physicochem. Closely. Aspects 263 (2005) 239-249 states that the effectiveness of a fatty alcohol-based defoamer depends on its state of aggregation. The effectiveness is highest when it is partially melted. This results in the demand in the art to use mixtures of fatty acid alcohols, which have a wider melting range than pure substances as mixtures.

In the prior art, the effectiveness of a defoamer is often measured by its ability to suppress foaming on a liquid surface. Especially in papermaking, however, it is more important to reduce the air content in the aqueous liquids produced in papermaking, especially in the pulp suspensions. Defoamers, which are also able to act as deaerators, are described less frequently in the prior art. With regard to the deaerating action, in particular at temperatures below 50 ° C., z. B. in the range of 20 to 50 ° C, often to be desired.

The object of the present invention is to provide compositions which have both high activity as defoamers and as deaerators for aqueous compositions, in particular for aqueous paper stock suspensions.

These and other objects are achieved by oil-in-water emulsions whose oil phase consists of at least 95% by weight of the following constituents: a) 40 to 95 wt .-%, based on the total weight of the oil phase, of a mixture of at least two alcohols as component A, consisting of:

a1) at least one alkanol having 12 to 30 C atoms as component A1,

a2) at least one mono- or diester of glycerol with at least one fatty acid having 14 to 24 carbon atoms as component A2; b) from 0.1 to 10% by weight, based on the total weight of the oil phase, of at least one further component B which comprises esters of C 12 -C 36 -alkanecarboxylic acids with polyglycerol, amides of C 12 -C 36 -alkanecarboxylic acids with alkylenediamines or oligoalkyleneamines, and C) 4.9 to 50 wt .-%, based on the total weight of the oil phase, of at least one further component C, which is selected from organic substances , which are liquid at 50 ° C and 1013 mbar, at normal pressure have a boiling point above 200 ° C and at 25 ° C and 1013 mbar have a solubility in water of less than 0.1 g / l.

Component A1 are preferably substantially unbranched alkanols having 12 to 30, preferably 14 to 28, in particular 16 to 26, especially 18 to 24 C atoms, d. H. saturated alcohols having 12 to 30, preferably 14 to 28, in particular 16 to 26, especially 18 to 24 C atoms which are at least 80%, in particular at least 90% and especially at least 95% linear and are accordingly described by the following formula can:

H- (CH ₂ ) _n -OH where n is an integer in the range of 18 to 24. The proportion of alkanols, in particular linear alkanols having 12 to 30, preferably 14 to 28, in particular 16 to 26 C-atoms, especially 18 to 24 C-atoms is generally at least 80 wt .-%, in particular at least 90 wt. %, especially at least 95 wt .-% or at least 99 wt .-%, based on the total weight of component A1. Examples of alcohols suitable as component A1 include lauryl alcohol, myristyl alcohol, palmityl alcohol (cetyl alcohol), 1-heptadecanol, stearyl alcohol, arachial alcohol (n-eicosanol), behenic alcohol, lignoceryl alcohol, cerotyl alcohol and mixtures thereof. Preferably, the component A is at least 80%, in particular at least 90% and especially at least 95% of one of the following Alkanols or mixtures thereof: stearyl alcohol, arachial alcohol, behenic alcohol and lignoceryl alcohol.

Furthermore, the component A1 preferably contains less than 10 wt .-%, in particular less than 5 wt .-%, especially less than 1 wt .-% or less than 0.5% by weight based on the component A1 alcohols with more than 30 C atoms or less than 12 C atoms.

In a likewise preferred embodiment, the component A1 used is arachialcohol, behenated alcohol, lignoceryl alcohol or a mixture of these alcohols, while the component A1 is substantially free of alcohols having more than 30 carbon atoms or less than 12 carbon atoms, ie. H. contains less than 0.5 wt .-%, based on the component A1, alcohols having more than 30 carbon atoms or less than 12 carbon atoms.

The proportion of component A1 in component A is generally in the range from 20 to 80% by weight, preferably from 25 to 75% by weight, in particular from 33 to 66% by weight, based on the total amount of component A. In a preferred embodiment, the components A1 and A2 are used in a weight ratio in the range from 4: 1 to 1: 4, in particular 3: 1 to 1: 3 and especially 2: 1 to 1: 2.

The component A2 is a mono- or diester of glycerol with at least one fatty acid having 14 to 24, in particular 16 to 22 and especially 18 to 22 C atoms, or a mixture of mono- or diester. A monoester of glycerol is understood as meaning a glycerol ester in which one of the 3 hydroxyl groups is in esterified form. Such substances are also referred to as monoglycerides. A diester of glycerol is understood as meaning a glycerol ester in which 2 of the 3 hydroxyl groups are present in esterified form. Such substances are also referred to as diglycerides. In terms of production, mono- and diesters are frequently present in the form of mixtures. As a result of the preparation, component A2 may also contain small amounts of triglycerides and glycerol, their proportions generally not exceeding 10% by weight in each case, in particular not more than 5% by weight, especially not more than 1% by weight Component A2.

The acid components of the mono- or diglycerides of component A2 may be both saturated fatty acids and unsaturated fatty acids and mixtures thereof. The fatty acids are preferably at least 70% by weight, in particular especially at least 80 wt .-%, especially at least 95 wt .-%, based on the total amount of fatty acids used linearly. Suitable fatty acids are preferably selected from saturated, linear fatty acids having 14 to 24, especially 16 to 22, especially 18 to 22 C-atoms. Examples of suitable saturated, linear fatty acids are myristic acid, palmitic acid, stearic acid, arachidic acid and behenic acid. Examples of suitable unsaturated, linear fatty acids are oleic acid, hexadecenes, elaidic acid, eicosenoic acids and docosenoic acids such as erucic acid or brassidic acid and polyunsaturated, linear acids such as octadecenedioic acids and octatrienoic acids such as linoleic acid and linolenic acid and mixtures of said saturated and unsaturated carboxylic acids. Component A2 is preferably selected from the mono- and diesters of glycerol with saturated, preferably linear, carboxylic acids having 16 to 22 carbon atoms, in particular palmitic acid, stearic acid and behenic acid and mixtures thereof. The mono- and diesters of glycerol used as component A2 preferably have a low iodine number, namely an iodine value of not more than 5 g per 100 grams and more preferably of not more than 2 grams per 100 grams of ester.

In a preferred embodiment, the component A2 is at least 80 wt .-%, preferably at least 90 wt .-%, in particular at least 95 wt .-% based on the total amount of component A2 of one or more mono- or diesters, preferably from one or more mono- or diesters of palmitic acid, stearic acid or behenic acid. Preferably, technical mixtures of these mono- or diesters are used as component A2. The component A2 regularly contains less than 20 wt .-%, preferably less than 10 wt .-%, in particular less than 5 wt .-% and especially less than 1 wt .-% based on the total amount of component A2 glycerol and triglycerides. The acid number of component A2 is generally not more than 10 mg KOH / g. In a particularly preferred embodiment, the component A2 is at least 80 wt .-%, preferably at least 90 wt .-%, in particular at least 95 wt .-%, based on the total amount of component A2, of mono- and diesters of glycerol and contains less than 20 wt .-%, preferably less than 10 wt .-%, in particular less than 5 wt .-% and especially less than 1 wt .-%, based on the total amount of the component A2, glycerol and triester of glycerol. The proportion of component A2 of component A is generally in the range from 20 to 80 wt .-%, preferably 25 to 75 wt .-%, in particular 33 to 66 wt .-%, based on the total amount of component A. The proportion of component A, ie the proportion of the total amount of constituents A1 and A2 in the oil phase, is in the range from 40 to 95% by weight, preferably from 50 to 80% by weight, in particular from 60 to 70% by weight. , based on the total weight of the oil phase. Component B is selected from esters of C 12-36 -alkanecarboxylic acids with polyglycerol, amides of C 12-36 -alkanecarboxylic acids with alkylenediamines or oligoalkyleneamines, esters of C 12-36 -alkanecarboxylic acids with C 12-36 -alkanols and mixtures thereof. Component B may contain small amounts of C12-C36 alkanecarboxylic acids as a result of the preparation. Preferably, the acid number of component B is not more than 10 mg KOH / g. Component B preferably has a low iodine number, namely an iodine value of at most 10 g of I 2 per 100 grams.

By esters of alkanecarboxylic acids with polyglycerol is meant a polyglycerol esterified with at least one fatty acid having from 12 to 36, in particular 16 to 30, especially 18 to 24, carbon atoms. The fatty acids which are suitable for the esterification of the polyglycerol may be both saturated fatty acids and unsaturated fatty acids and mixtures thereof. Suitable fatty acids for the esterification of the polyglycerol mixtures are preferably selected from saturated fatty acids having 12 to 36, in particular 16 to 30, especially 18 to 24, carbon atoms. Examples of suitable saturated fatty acids are lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, behenic acid and montan wax acid. Examples of suitable unsaturated fatty acids are oleic acid, hexadecanoic acids, elaidic acid, eicosenoic acids and docosenoic acids such as erucic acid or brassidic acid and polyunsaturated acids such as octadecenedioic acids and octatrienoic acids such as linoleic acid and linolenic acid and mixtures of said saturated and unsaturated carboxylic acids. Preferably, the polyglycerol is esterified with saturated carboxylic acids having 18 to 24 carbon atoms, which is selected in particular from palmitic acid, stearic acid and behenic acid and mixtures thereof. In a specific embodiment, the polyglycerol ester is a behenic acid esterified polyglycerol.

A polyglycerol is understood as meaning oligomers of glycerol which contain at least 50% by weight, in particular at least 60% by weight, of di-, tri- or tetraglycerol or higher glycerol oligomers. Preferred polyglycerols contain 15 to 40% by weight Diglycerin, 30 to 55 wt .-% triglycerol and 10 to 25 wt .-% tetraglycerol, each based on the total amount of polyglycerol, wherein the total amount of di-, tri and tetraglycerol preferably at least 60 wt .-%. The degree of esterification of the polyglycerol esters is generally from 20 to 100%, preferably from 60 to 100%, based on the number of hydroxyl functions in the polyglycerol. The acid number of the polyglycerol ester is usually not more than 10 mg KOH / g. Preferably, the polyglycerol ester has a low iodine value, namely an iodine value of not more than 10 g per 100 grams of polyglycerol ester.

Preferred polyglycerol esters are, in particular, those which are obtainable by esterification of polyglycerol mixtures which comprise 15 to 40% by weight of diglycerol, 30 to 55% by weight of triglycerol and 10 to 25% by weight of tetraglycerol, in each case based on the total amount of polyglycerol, contain, wherein the total amount of di-, tri and tetraglycerin at least 60 wt .-% makes up. In particular, mixtures of the following composition are used for the esterification:

0 to 10% by weight of glycerol,

15 to 40% by weight of diglycerol,

From 30 to 55% by weight of triglycerol,

From 10 to 25% by weight of tetraglycerol,

0 to 15% by weight of pentaglycerol,

0 to 10 wt .-% hexaglycerol and

0 to 5 wt .-% higher condensed polyglycerols.

In particular, the polyglycerol esters are those which are obtainable by esterification of one of the above-described polyglycerol mixtures with at least one saturated carboxylic acid having 18 to 24 carbon atoms, the carboxylic acid being selected in particular from palmitic acid, stearic acid and behenic acid and mixtures thereof Behenic acid is particularly preferred.

Particular preference is given to using polyglycerol esters which consist of the esterification of behenic acid with a polyglycerol mixture consisting of 0 to 10% by weight of glycerol, 15 to 40% by weight of diglycerol, 30 to 55% by weight of triglycerin, 10 to 25% by weight. % Tetraglycerol, 0 to 15 wt .-% pentaglycerol, 0 to 10 wt .-% hexaglycerol and 0 to 5 wt .-% higher condensed polyglycerols are available.

The polyglycerol mixtures used for the esterification are, for example, by alkaline-catalyzed condensation of glycerol at elevated temperatures (cf. Fats, soaps, paints, 88 Volume, No. 3, pages 101 to 106 (1986) or according to DE-A 3,842,692 by reaction of glycerol with epichlorohydrin in the presence of acidic catalysts at elevated temperatures accessible. However, the mixtures are also obtainable by using the pure polyglycerol, z. As diglycerol, triglycerol and tetraglycerol mixed together.

The esterified with alkanecarboxylic polyglycerols are known, for. From EP 0531713 and WO 94/08091. They are typically prepared by esterifying polyglycerol, in particular by esterifying the previously described polyglycerol mixtures, with the desired fatty acid or mixture of fatty acids or their ester-forming derivatives, eg. B. their Ci-C4-alkyl esters, prepared by methods known per se. This is usually carried out in the presence of an acidic esterification catalyst such as sulfuric acid, p-toluenesulfonic acid, citric acid, phosphorous acid, phosphoric acid, hypophosphorous acid or basic catalysts such as sodium or potassium tert-butoxide.

Further suitable as component B are amides of C 12 -C 36 -alkanecarboxylic acids with alkylenediamines, oligoalkyleneamines and mixtures thereof. These amides are understood to mean substances which are prepared by amidation of at least one, preferably saturated, mono- to dihydric, preferably monohydric, fatty acid having 12 to 36, in particular 16 to 30, especially 18 to 24 C atoms with one selected from alkylenediamines and oligoalkyleneamines Amine are available. Such substances are z. B. from DE 101 27 245 known. The acid number of the amides of C12-C36 alkanecarboxylic acids is generally not more than 10 mg KOH / g.

Suitable amidation amines are alkylenediamines, oligoalkyleneamines and mixtures thereof. Alkylenediamines are understood as meaning compounds which have two amino functions linked via a linear or branched alkylene group, it being possible for the alkylene group to be interrupted by 2, 3 or 4 nonadjacent oxygen atoms. Alkylenediamines are preferably linear and preferably the amino functions are terminal. Accordingly, alkylenediamines can be described in particular by the following formula: wherein A is an alkylene group having usually 2 to 10 carbon atoms, wherein 1, 2, 3 or 4 non-adjacent Ch groups may be replaced by oxygen. Examples are ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, 1,5-pentylenediamine and hexamethylenediamine, and 2- (2-aminoethoxy) ethylamine, 2- [2- (2- Aminoethoxy) ethoxy] ethylamine, 3- (3-aminopropoxy) propylamine, 3- [2- (3-amino)

Aminopropoxy) ethoxy] propylamine or 2- [3- (2-aminoethoxy) propoxy] ethylamine.

Oligoalkyleneamines are compounds having generally two terminal amino groups which are interrupted by at least one imino group (NH). Preferably, oligoalkyleneamines can be described by the following formula:

NH ₂ -C _m H2m-NH (-C n H 2n NH) x C _m H2m-NH ₂ wherein n and m independently represent an integer in the range of 2 to 10, preferably 2 to 8, in particular 2 to 6 and X is an integer in the range of 0 to 50, preferably 0 to 20, in particular 0 to 10 stands. In a preferred embodiment, m and n are independently 2 or 3 and X is 0, 1 or 2. In particular, m is 3, n is 2 and X is 1 (3- [2- (3-aminopropylamino) ethylamino] propylamine ) or m is 2 and X is 0 (diethylenetriamine) or m and n is 2 and X is 1 (triethylenetetramine).

Examples of preferred alkylenediamines and oligoalkyleneamines are diethylenetriamine, triethylenetetramine, 3- [2- (3-aminopropylamino) ethylamino] propylamine, 2- (2-aminoethoxy) ethylamine, 2- [2- (2-aminoethoxy) ethoxy] ethylamine 3 - (3-aminopropoxy) propylamine, 3- [2- (3-aminopropoxy) ethoxy] propylamine or 2- [3- (2-aminoethoxy) propoxy] ethylamine and mixtures thereof.

As component B and mixtures of amides of C12-C36 alkanecarboxylic acids with alkylenediamines, oligoalkyleneamines or mixtures thereof can be used.

As component B, esters of C 12 -C 36 -alkanecarboxylic acids with C 12 -C 36 -alkanols are also suitable. This refers to substances which are obtainable by esterification of at least one, preferably saturated, mono- to dihydric, preferably monohydric, alkanecarboxylic acid having 12 to 36, in particular 16 to 30, especially 18 to 24 C-atoms with a Ci2-C36-alkanol , The alkanols suitable for the esterification are preferably saturated, linear and mono- to divalent, in particular monovalent. They have 12 to 36, especially 16 to 30, especially 18 to 24 carbon atoms. It is also possible to use mixtures of alkanoic acid alkyl esters. Suitable examples of alkanoic acid alkyl esters are Palmitinsäurepalmitylester, Stearinsäuresteary lester, Arachinsäurearachylester, behenyl behenate and Lignocerinsäureligno- cerylester. Preferred esters of C 12 -C 36 -alkanecarboxylic acids with C 12 -C 36 -alkanols are behenyl behenate and stearyl stearate and mixtures thereof. In a preferred embodiment, component B comprises at least one of the previously described esters of alkanecarboxylic acids with polyglycerol (hereinafter also referred to as polyglycerol ester), in particular at least one of the polyglycerol esters indicated as being preferred or particularly preferred. In a preferred embodiment, component B comprises at least one of the above-described polyglycerol esters obtainable by esterification of the above-described polyglycerol with at least one saturated carboxylic acid having 18 to 24 carbon atoms, the carboxylic acid being in particular palmitic acid, stearic acid and behenic acid and whose mixtures are selected. In a particularly preferred embodiment, component B comprises at least one of the previously described polyglycerol esters obtained by esterification of behenic acid with a polyglycerol mixture consisting of 0 to 10% by weight of glycerol, 15 to 40% by weight of diglycerol, 30 to 55% by weight. % Triglycerol, 10 to 25 wt .-% tetraglycerol, 0 to 15 wt .-% pentaglycerol, 0 to 10 wt .-% hexaglycerol and 0 to 5 wt .-% higher condensed polyglycerols is available.

In a preferred embodiment, the component B is at least 80 wt .-%, in particular at least 90 wt .-%, especially at least 95 wt .-%, based on the total weight of component B, or exclusively of at least one of the previously described Polyglycerolester, in particular at least one of the polyglycerol esters given as preferred or particularly preferred. In a particularly preferred embodiment, the component B is at least 80 wt .-%, in particular at least 90 wt .-%, especially at least 95 wt .-%, based on the total weight of component B, or exclusively of at least one of the above described polyglycerol ester which is obtainable by esterification of the polyglycerol described above with at least one saturated carboxylic acid having 18 to 24 carbon atoms, wherein the carboxylic acid is selected in particular from palmitic acid, stearic acid and behenic acid and mixtures thereof. In a particularly preferred embodiment, the component B is at least 80 wt .-%, in particular at least 90 wt .-%, especially at least 95 wt .-%, based on the total weight of component B, or exclusively of at least one of the above polyglycerol ester described by esterification of behenic acid with a polyglycerol mixture consisting of 0 to 10 wt .-% glycerol, 15 to 40 wt .-% diglycerol, 30 to 55 wt .-% triglycerol, 10 to 25 wt .-% tetraglycerol , 0 to 15 wt .-% pentaglycerol, 0 to 10 wt .-% hexaglycerol and 0 to 5 wt .-% higher condensed polyglycerols is available. According to the invention, the proportion of component B in the oil phase is from 0.1 to 10% by weight, preferably from 2 to 8% by weight, in particular from 3 to 6% by weight, based on the total weight of the oil phase. The component C contained in the oil-in-water emulsions according to the invention is one or more organic substances which are liquid at 50 ° C. and 1013 mbar, at normal pressure a boiling point above 200 ° C., eg. B. in the range of 200 to 400 ° C, in particular at least 250 ° C, and which are substantially insoluble in water at 25 ° C and 1013 mbar in water, ie have a solubility in water of less than 0.1 g / l. Suitable substances are hydrocarbons and triglycerides of fatty acids, in particular those having 12 to 22 carbon atoms. Component C preferably consists of at least 80% by weight, in particular 90% by weight, especially 95% by weight, based on the total weight of component C, of one or more hydrocarbons which are in particular non-aromatic, ie aliphatic or cycloaliphatic, are and have a boiling point of at least 200 ° C, preferably at least 250 ° C, z. B. in the range of 200 to 400 ° C or 250 to 400 ° C at 1, 013 bar, such as vegetable and animal oils and aliphatic hydrocarbons, such as liquid paraffins, white oils, soft paraffins, or other commercially available mineral oils.

The proportion of component C in the oil phase according to the invention is 4.9 to 49 wt .-%, preferably 20 to 40, in particular 25 to 35 wt .-% based on the total weight of the oil phase. To stabilize the oil in the aqueous emulsion, it is advantageous if at least one surface-active substance is present in the emulsions according to the invention. The emulsions of the invention contain at least ei ne surface-active substance, usually in an amount of 0, 1 to 1 0 wt .-%, in particular in an amount of 0.5 to 5 wt .-%, based on the oil phase.

As surface-active substances, in principle all substances known for stabilizing hydrophobic particles or droplets in aqueous systems are suitable, eg. As anionic, cationic, amphoteric and / or nonionic emulsifiers and water-soluble ionic and nonionic polymers, preferably ionic amphiphilic copolymers having cationic or anionic groups and their molecular weight, in contrast to the emulsifiers usually above 1000 daltons. Surface-active substances are well known to the skilled person, for. From Ullmann's Encyclopedia of Industrial Chemistry, 5th ed., Vol. A9, pp. 297-339. Examples of suitable anionic emulsifiers are:

Salts, especially sodium and ammonium salts, higher fatty acids,

For example, the sodium and ammonium salts, sulfated ethoxylation products of C 6 -C 22 -alkylphenols such as nonylphenol or octylphenol, salts, in particular the sodium and ammonium salts, of C 4 -C 22 -alkyl aryl sulfonates, salts, in particular the sodium and ammonium salts, of sulfonates of naphthalene,

Salts, in particular the sodium and ammonium salts, of sulfonated C 8 -C 22 -alkyldiphenyloxides, in particular of bis-sulfonated C 8 -C 22 -alkyldiphenyloxides, such as bis-sulfonated dodecyldiphenyloxide,

Salts, in particular the sodium and ammonium salts, of naphthalenesulfonic acid / formaldehyde condensates or naphthalenesulfonic acid / formaldehyde / urea condensates,

and salts, especially the sodium and ammonium salts, of di-C 4 -C 20 -alkyl sulfosuccinates;

Examples of suitable nonionic emulsifiers are: alkoxylated C 6 -C 22 -alkylphenols having a degree of ethoxylation preferably in the range from 5 to 50,

ethoxylated unsaturated oils such as reaction products of one mole of castor oil and 30 to 40 moles of ethylene oxide, and

Addition products of ethylene oxide and / or propylene oxide with aliphatic alcohols having usually 12 to 20 carbon atoms, for. As to fatty alcohols, polyhydric alcohols, amines and carboxylic acids.

The emulsions according to the invention preferably contain at least one emulsifier, in particular at least one anionic emulsifier in an amount of from 0.1 to 10% by weight, in particular in an amount of from 0.5 to 5% by weight, based on the oil phase. In a specific embodiment, the emulsions according to the invention contain at least one anionic emulsifier selected from among the salts, in particular the sodium and ammonium salts of sulfated ethoxylation products of C6-C22-alkylphenols.

Examples of surface-active anionic polymers are homopolymers of acrylic acid, homopolymers of methacrylic acid, copolymers of acrylic acid and methacrylic acid in any molar ratio, copolymers of acrylic acid and maleic acid in any molar ratio, copolymers of methacrylic acid and maleic acid, polyvinyl sulfonic acid, polyacrylamido-2 methylpropanesulfonic acid, styrenesulfonic acid, copolymers of acrylic acid and acrylamide or methacrylamide, copolymers of methacrylic acid and acrylamide or methacrylamide, or the alkali metal and ammonium salts of said polymers having molecular weights of, for example, 1500 to 300,000.

Preferred anionic surface-active polymers are amphiphilic, acid group-containing copolymers which

(a) hydrophobic monoethylenically unsaturated monomers and

(b) monoethylenically unsaturated carboxylic acids, monoethylenically unsaturated sulfonic acids, monoethylenically unsaturated phosphonic acids or mixtures thereof, and optionally various monomers (c) in copolymerized form, and the salts, in particular the sodium and the ammonium salts.

Examples of hydrophobic monoethylenically unsaturated monomers are: styrene, methylstyrene, ethylstyrene, acrylonitrile, methacrylonitrile, C 2 - to cis-olefins, esters of monoethylenically unsaturated C 3 - to Cs-carboxylic acids and monohydric alcohols, vinyl alkyl ethers, vinyl esters or mixtures thereof. Isobutene, diisobutene, styrene and acrylic esters such as ethyl acrylate, isopropyl acrylate, n-butyl acrylate and sec-butyl acrylate are preferably used from this group of monomers. Examples of monomers (b) are: acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, vinylsulfonic acid, 2-acrylamidomethylpropanesulfonic acid, acrylamidopropane-3-sulfonic acid, 3-sulfopropyl acrylate, 3-sulfopropyl methacrylate, styrenesulfonic acid, vinylphosphonic acid or mixtures thereof polymerized form, with acrylic acid, methacrylic acid and maleic acid and its anhydride are preferred.

The molecular weight of the amphiphilic copolymers is generally from 1000 to 100,000 and is preferably in the range from 1,500 to 1,000. The acid numbers of the anionic phi philen copolymers are generally 50 to 500, preferably 150 to 350 mg KOH / g ,

Further suitable surface-active polymers for stabilizing the compositions according to the invention are: Graft polymers of from 5 to 40 parts by weight of N-vinylformamide per 100 parts by weight of a polyalkylene glycol having a molecular weight of from 500 to 10,000,

Zwitterionic polyalkylenepolyamines,

Zwitterionic polyethyleneimines,

· Zwitterionic polyether polyamines or

• zwitterionic crosslinked polyalkylenepolyamines.

Pfropfpo l ym e ri sate of N-vinylformamide on polyalkylene glycols are described for example in WO-A-96/34903. The grafted vinylformamide units may optionally be hydrolyzed up to 10%. The proportion of grafted vinylformamide units is preferably 20 to 40% by weight, based on polyalkylene glycol. Polyethylene glycols having molecular weights of 2,000 to 10,000 are preferably used. Zwitterionic polyalkylene polyamines and zwitterionic polyethyleneimines are known, for example, from EP-B 1 12592. Such compounds are obtainable, for example, by first alkoxylating a polyalkylenepolyamine or polyethylenimine, eg. B. with ethylene oxide, propylene oxide and / or butylene oxide, and the alkoxylation products then quaternized, eg with methyl bromide or dimethyl sulfate and the quaternized alkoxylated products then sulfated with chlorosulfonic acid or sulfur trioxide. The molar mass of the zwitterionic polyalkylenepolyamines is for example 1000 to 9000, preferably 1500 to 7500. The zwitterionic polyethyleneimines preferably have molecular weights in the range from 2000 to 1700 daltons. Preferably, the compositions of the invention contain at least one anionic surfactant. This is preferably selected from the above-mentioned anionic emulsifiers, the above-mentioned acid group-bearing, water-soluble polymers and mixtures thereof. For the stability of the emulsions according to the invention, it has proved to be advantageous if they contain 0.05 to 8% by weight, in particular 0.1 to 5% by weight, based on the oil phase, of at least one acid group-containing, water-soluble, homo- or copolymer, preferably a salt thereof and optionally at least one anionic emulsifier. The emulsifiers are preferably also used in an amount of 0.05 to 5 wt .-%, based on the total weight of the oil phase. Particularly advantageous are those emulsions containing at least one anionic emulsifier and at least one of the above-mentioned acid group-bearing, water-soluble polymers. The emulsions according to the invention can, as further disperse constituent, in addition to the oil phase, comprise finely divided, practically water-insoluble, inert solids with particle sizes <20 μm, preferably 0.1 to 10 μm in an amount of for example 0.1 to 50, preferably 1 to 35% by weight Oil phase of the oil-in-water emulsions. The solids content of the emulsion is according to the invention in a range of 10 to 50%, in particular 15 to 45%, especially 20 to 40%. Suitable inert solids are, for example, kaolin, chalk, bentonite, talc, barium sulfate, silica, zeolites, urea-formaldehyde pigments, melamine-formaldehyde pigments and microcrystalline cellulose, wherein the inert inorganic pigments may also be hydrophobic, z. B. by treatment with trialkylsilyl halides. In a preferred embodiment of the invention, the emulsions contain no finely divided, practically water-insoluble, inert solids other than components A, B and C. Frequently, the emulsions according to the invention for adjusting the viscosity required for the particular application still contain at least one thickener. In principle, all thickeners known for thickening of oil-in-water systems can be used. These include natural thickeners such as polysaccharides, carrageenates, tragacanth, alginates, starch, caseinates, modified organic polymers such as carboxymethylcellulose, synthetic thickeners such as polyacrylic acids, polyvinyl alcohol, polyethylene glycols, polyacrylamides and in particular copolymers of acrylamide with ethylenically unsaturated carboxylic acids, in particular with acrylic acid, and optionally with comonomers. These thickeners are described in EP-A 149812, the disclosure of which is hereby incorporated by reference. Other suitable thickeners are mentioned in the review article by Warren B. Shapiro, Oil-in Water-Emulsions, Cosmetics & Toiletries, Vol. 97, 1982, 27-33. Also particularly preferred are so-called associative thickeners, for. As hydrophobically modified polyurethanes, hydrophobically modified cellulose ethers that build up high molecular weight network structures according to the principle of hydrophobic interaction in the aqueous phase. Associative thickeners are known in the art, for. From J. Bielemann, Additives for Coatings, Wiley-VCH, Weinheim, 2000 and available commercially, e.g. B. under the names RHOPLEX ^® and PRIMAL ^® TT 935 Fa. Rohm & Haas, USA. In a preferred embodiment of the invention, the emulsions contain no thickener.

Furthermore, emulsions according to the invention often contain for preservation even commercial biocides, eg. As formaldehyde, isothiazole and the products sold by ICI under the name PROXEL ^® products. To prepare the emulsion according to the invention, the oil phase will generally be emulsified in the aqueous phase. This is done in a conventional manner in analogy to processes for the preparation of emulsions. Typically, this emulsifiers, for. B. dispersants in which the components of the emulsion are subjected to a high shear rate. In order to obtain particularly stable oil-in-water emulsions, the emulsification of the oil phase in the aqueous phase is preferably carried out in the presence of surface-active substances.

By emulsifying the oil phase into the aqueous phase, oil-in-water emulsions are obtained. These usually have a viscosity in the range of 300 to 3000 mPa · s immediately after preparation. The mean particle size of the oil droplets (weight average droplet diameter) of the oil-in-water emulsion is generally below 25 μm, preferably in the range from 0.1 to 20 μm, in particular 0.5 to 15 μm, especially 1 to 10 μηη, determined by light scattering at 20 ° C. The solids content of the oil-in-water emulsion is in a range of 10 to 50 wt .-%, preferably 20 to 40 wt .-%, as z. B. by reweighing after drying can be determined.

The oil-in-water emulsions according to the invention can be used as defoamers and / or deaerators for foam control or deaeration of aqueous compositions, for example in the food industry, the starch industry, in sewage treatment plants or in the paper industry. Preference is given to their use as a wellbore solution and in the paper industry, in particular in the cell fuel cook, pulp washing, the milling of pulp, papermaking and the dispersion of pigments for papermaking. Specifically, the oil-in-water emulsions of the invention are used in the paper industry as a deaerator for aqueous paper stock suspensions. Particularly preferred is the use as a breather of the headbox in papermaking. As defoamers or deaerators, the oil-in-water emulsions are generally used in amounts of 0.01 to 2 parts by weight per 100 parts by weight of the foam-forming aqueous liquid, preferably in amounts of 0.02 to 1 wt. Parts per 100 parts by weight of the foam-forming liquid, in particular in amounts of 0.05 to 0.5 parts by weight per 100 parts by weight of the foam-forming liquid used.

The advantages of the emulsions according to the invention come in particular at temperatures in the range of 20 to 50 ° C to bear. The following examples are intended to further illustrate the invention and are not intended to be limiting.

Physicochemical investigation methods

The average particle size (d50) of the water-emulsified particles of the oil phase was determined with the aid of a Coulter counter from Beckmann.

Viscosity was determined using a Brookfield type RVT rotary viscometer, spindle 4 at 20 revolutions per minute at 25 ° C.

The solids content was determined by weighing the samples after storage in a drying oven at 1 10 ° C to constant weight. The average air content was determined by pumping in a container of transparent plastic 10 l each of a foam-developing stock suspension 0.1% (groundwood) for 5 minutes. The quantity of air formed in the stock suspension was then recorded with the aid of an air meter (eg based on impedance methods such as the Sonica instrument from Conrex or on the basis of sound velocity measurements such as the Sonatrac from Cidra). To assess the effectiveness of a deaerator, the average air content was given 5 minutes after the addition of the deaerator.

Pumping the paper suspension in the absence of a defoamer for 5 minutes, we obtain an average air content of 4%. By adding 5 mg / l of an effective deaerator to the stock suspension, this value is significantly reduced, thus providing a measure of the effectiveness of a deaerator.

Depending on the test, the temperature of the paper stock suspension was 30, 40 or 50 ° C., the temperature being kept constant at +/- 1 ° C. during the 5-minute test. In this terminology, the smaller the average air content of the pulp suspension, the more effective is the defoamer.

The parts given in the examples are parts by weight.

The C2o + fatty alcohol mixture used below as component A1 consists of 6% by weight of a linear cis-alcohol, to 50% by weight of a linear C20-alcohol, to 29% by weight of a linear C22-alcohol, to 14% by weight of a linear C24 alcohol and 3% by weight of a linear C26 alcohol. The melting range of this mixture is 53 to 58 ° C.

In the following, the glycerol stearates of the following composition were used as component A2:

It is a mixture of 50 to 75 wt.% Monoester of glycerol and 25 to 50 wt .-% of the diester of glycerol with a Ci6- / Ci8-carboxylic acid mixture containing about 40 to 70 wt .-% of palmitic acid and 30 to 60 wt .-% of stearic acid. The iodine value is less than 2 g / 100 g. The acid number is less than 10 mg KOH / g.

Glycerin stearate 1 is a glycerol stearate marketed under the name Glycerin Monostearat by Faci Spa. Glycerol Stearate 2 is a Radiamuls MG 2143 from Oleon N.V. or the company Brenntag Polska distributed Glycerinstearat.

The polyglycerol ester is an esterification product of a polyglycerine mixture consisting of 27% diglycerol, 44% triglycerol, 19% tetraglycerol and 10% higher condensed polyglycerols, with behenic acid having an acid value <10 mg / g KOH.

As component C commercial rapeseed oil or commercial palm oil was used. The surface-active substances used were the emulsifier Emulan TO 4070, a mixture of ethoxylated fatty alcohols, commercially available from BASF SE.

The thickener used was an aqueous 1% strength xanthan solution. As a biocide formaldehyde and Proxel ^® were, which rkstoff on the Wi 1, 2- benzisothiazolin-3-based οη and is marketed by Arch used.

Example 1 The components of the oil phase were first heated to a temperature of 100 to 1 10 ° C and then incorporated by means of a dispersing agent in the heated to 80 ° C to 95 ° C aqueous phase and then cooled to 25 ° C with an ice bath. Subsequently, the obtained emulsion was filtered. The oil phase had the following composition based on the total weight of the emulsion:

9.2 parts of the C2o + fatty alcohol mixture,

• 9.2 parts glyceryl distearate

• 7.3 parts rapeseed oil,

• 1, 6 parts of polyglycerol ester,

0.1 part of formaldehyde (30%)

• 0.1 parts Proxel ^®.

The water phase was based on the total weight of the emulsion:

• 46.9 parts of water,

• 25 parts xanthan (1%),

0.6 part of emulsifier Emulan TO 4070 (70%)

The examples and comparative examples given in Table 1 were prepared in an analogous manner. The amounts are wt .-%, based on the total weight of the emulsion. The composition of the water phase corresponded in all examples to the water phase of Example 1. The physical properties and the deaerating effect of this emulsion are given in Table 2.

Table 1: Composition of Examples and Comparative Examples

Table 2: physical properties and de-aerating properties of the antifoam agents average particle pH viscosity solids content air content [%] size (d ₅ o) [pm] [mPa-s] [%] 40 ° C

1 2.3 7.3 1200 28.9 0.21

2 3.2 6.4 2320 27.7 0.23

3 3.2 6.5 2360 28.1 0.28

V1 2.8 7.1 630 28.0 0.60

V2 3.7 7.1 1 130 28.7 0.76

V3 2.7 6.3 3330 27.9 0.79

Claims

claims

1 . An oil-in-water emulsion in which the oil phase consists of at least 95% by weight of the following constituents: a) from 40 to 95% by weight, based on the total weight of the oil phase, of a mixture of at least two alcohols Component A, consisting of:

a1) at least one alkanol having 12 to 30 C atoms as component A1,

a2) at least one mono- or diester of glycerol with at least one fatty acid having 14 to 22 C atoms as component A2; b) from 0.1 to 10% by weight, based on the total weight of the oil phase, of at least one further component B which comprises esters of C 12 -C 36 -alkanecarboxylic acids with polyglycerol, amides of C 12 -C 36 -alkanecarboxylic acids with alkylenediamines or oligoalkyleneamines, and C) 4.9 to 50 wt .-%, based on the total weight of the oil phase, of at least one further component C, which is selected from organic substances , which are liquid at 50 ° C and 1013 mbar, at normal pressure have a boiling point above 200 ° C and at 25 ° C and 1013 mbar have a solubility in water of less than 0.1 g / l.

2. oil-in-water emulsion according to claim 1, wherein the component A1 consists of 80% of linear alkanols having 16 to 26 carbon atoms.

An OI-in-water emulsion according to claim 1 or 2, wherein component A2 consists of at least 80% by weight of at least one mono- or di-ester of glycerol with at least one linear C 1-4 -alkanoic acid.

An oil-in-water emulsion according to any one of the preceding claims wherein component A2 is at least 80% by weight of at least one mono- or di-ester of glycerol with at least one linear C 16 -C 22 alkanecarboxylic acid.

5. oil-in-water emulsion according to any one of the preceding claims, wherein the weight ratio of component A1 to component A2 in the range of 1: 4 to 4: 1.

6. oil-in-water emulsion according to any one of the preceding claims, wherein the component B consists of at least 80 wt .-% of the esters of at least one Cie-C24-alkanecarboxylic acid with polyglycerol.

7. An oil-in-water emulsion according to claim 6, wherein the polyglycerol ester is obtainable by esterification of polyglycerol with behenic acid.

8. oil-in-water emulsion according to any one of the preceding claims, wherein the component C consists of at least 80 wt .-% of aliphatic hydrocarbon oils.

9. An oil-in-water emulsion according to any one of the preceding claims, wherein the solids content of the emulsion is in a range of 10 to 50%.

10. Oil-in-water emulsion according to one of the preceding claims, whose weight-average particle size of the oil droplets of the oil-in-water emulsion in a range of 0.5 to 10 μηη.

1 1. Use of the oil-in-water emulsion according to any one of the preceding claims as a defoamer or deaerator in aqueous compositions.

12. Use of the oil-in-water emulsion according to claim 1 1 as a deaerator for aqueous Papierstoffsuspensionen.

13. Use of the oil-in-water emulsion according to claim 12 as a breather of the headbox in papermaking.

14. Use of the oil-in-water emulsion according to claim 10 to 13 at temperatures of 20 to 50 ° C.