MXPA99006523A - Low-foam emulgator system and emulsion concentrate containing the same - Google Patents

Abstract

The invention relates to a low-foam emulgator system consisting of a) ethoxylates/propoxylates of fatty alcohols with 8-18 C-atoms in the alcohol with 2-6 ethylene oxide units and 4-8 propylene oxide units and b) fatty alcohols or their distillation residues, and/or fatty alcohol propoxylates with 12-24 C-atoms in the alcohol and 0-3 propylene oxide units in a weight ratio of a:b=1:0.3 to 0.3:1. The invention also relates to an anti-corrosion and emulgator system containing, in addition, corrosion inhibiting carboxylic acids, as well as a water miscible emulsion concentrate obtainable herefrom by adding oil. From this, water-mixed emulsions can be obtained, which can be used as cleaning, anti-corrosion or cooling lubricant emulsions in metal processing.

Description

LOW FOAM AND CONCENTRATED EMULSION EMULSIFIER SYSTEM CONTAINING SUCH SYSTEM This invention relates to an emulsifier system which is suitable for the production of oil-in-water emulsions with low foaming in mild water. The system and ulsifier can be combined with suitable carboxylic acids to create a system of protection against corrosion. The present invention also relates to a water-miscible emulsion concentrate containing oil in the present emulsifier system, and ready-to-use oil-in-water emulsions prepared therefrom. Even in mild water, these emulsions have only a slight tendency to form foam and can be used for different applications of industrial metal processing, for example as in cleaning emulsions, corrosion protection or cold lubricants. The emulsions for protection against corrosion are used as passivating agents to temporarily protect metal parts from corrosive atmospheric influences. These contain mainly apolar or polar oils, emulsifiers, corrosion inhibitors and water. Conventional commercial systems are based on oil concentrates that contain emulsifiers and corrosion inhibitors, but little or no water. The emulsifiers and the corrosion inhibitors must, in this way, be soluble in oil. To produce oil-in-water emulsions (* 0 / W emulsions) that are used in diluted form with water, these systems must be self-emulsifying.The cooling lubricant emulsions used for machining and forming metal parts have a composition similar to corrosion protection emulsions, as they must also present a corrosion inhibiting action, the lubricating action can be improved by the addition of suitable lubricant additives.A common feature of all these types of emulsion is that they have a tendency to form Due to the emulsifiers that are used, the tendency to foam is particularly pronounced if the emulsifier system contains anionic surfactants In the case of use in hard water, the tendency to form foam decreases due to the fact that the anionic surfactants they can react with calcium ions to form salts with little sun ubles that have a foam-inhibiting action. In soft to semi-hard water, that is, in water having a hardness less than 12 ° and in particular less than 8 ° dH [German hardness], these emulsions are inadequate due to the increased tendency to foam, at least if These are used - in spray applications. Emulsifier systems containing only non-ionic emulsifiers are known from DE-A-39 33 137 and DE-A-43 23 908. The emulsifier system according to DE-A-39 33 137 consists of at least one addition product of 2 to 20 mol of ethylene oxide on fatty alcohols having from 10 to 22 carbon atoms, to which can be added up to an identical number of parts, by weight, of a co-emulsifying component consisting of at least one alcohol fatty with 12 to 22 carbon atoms. The emulsifier system according to DE-A-43 23 908 consists of at least one addition product of 5 to 12 mol of ethylene oxide on fatty alcohols with 16 to 18 carbon atoms and at least one addition product of 1 to 2 moles of ethylene oxide in fatty alcohols having 12 to 18 carbon atoms, or at least one monoglycerol ester of fatty acids having 16 to 18 carbon atoms. The emulsion concentrates according to these arguments are produced using the so-called 'phase inversion process.' The disadvantageous characteristics in this regard include the relatively high water content of the emulsion concentrates, the elaborate production process and the low content possible inhibitor of the concentrates In addition, the stability of the emulsion of the concentrate itself must be optimized, thus limiting the possible latitude in the formulation.

An object of the present invention is to provide an emulsifier system with which low water or anhydrous emulsion concentrates for O / W emulsions can be produced with simple agitation. The ready-to-use O / W emulsions obtainable from these concentrates by combination with water should also have only a low tendency to foam even in mild water. This objective is achieved by a low foam emulsifier system consisting of: (a) ethoxylated / propoxylated fatty alcohols having 8 to 18 carbon atoms in the alcohol with 2 to 6 ethylene oxide units and 4 to 8 propylene oxide units; and (b) fatty alcohols and / or propoxylates of fatty alcohols having from 12 to 24 carbon atoms in the alcohol and from 0 to 3 units of propylene oxide and / or the distillation residue of these fatty alcohols; in a ratio, by weight, of (a): (b) from 1: 0.3 to 0.3: 1.

In this way, narrow limits are established in the composition of the emulsifier system and in the molecular structure of the emulsifiers used. On the one hand, according to (a) the ethoxylated / propoxylated fatty alcohols carrying from 2 to 6 ethylene oxide units and from 4 to 8 propylene oxide units must be present. These hydrophilizing components must be combined with the component (b) fatty alcohols having from 12 to 24 carbon atoms more hydrophobic, non-alkoxylated, the distillation residue thereof or the products of akoxylation thereof with an average content of up to no more than 3 units of propylene oxide. It is also necessary to comply with the approximate ratio mentioned, by weight. The distillation residue of the fatty alcohols containing from 12 to 24 carbon atoms is obtained as 'Pemil® RU' from Henkel KGaA, Dusseldorf As already described, this emulsifier system can be formulated with other components to produce cleaning emulsions, protection against corrosion and / or coolant The emulsifier system can, however, be offered for sale as it is.The buyer must then use it to prepare the desired type of emulsion.In a first stage, the emulsifier system can be formulated with a component for protection against corrosion, from which a concentrate for a corrosion protection emulsion can be produced by adding oil According to a second embodiment, the present invention thus relates to an emulsifying and protection system. Corrosion consisting of: from 15 to 40 parts by weight of one or more linear or branched carboxylic acids having from 6 to 10 carbon atoms or the anions thereof; and from 15 to 40 parts by weight of the emulsifier component consisting of: (a) ethoxylated / propoxylated fatty alcohols having 8 to 18 carbon atoms in the alcohol with 2 to 6 ethylene oxide units and 4 to 8 propylene oxide units; and (b) fatty alcohols and / or propoxylates of fatty alcohols having from 12 to 24 carbon atoms in the alcohol and from 0 to 3 units of propylene oxide and / or the residue from the distillation of these fatty alcohols; in a weight ratio of (a): (b) from 1: 0.3 to 0.3: 1, Since emulsions for protection against corrosion usually have neutral to basic pH values, it is possible to use the carboxylic acids at least in part in neutralized form, that is, as salts. The basic components suitable for neutralization are potassium hydroxide solution and / or alkanolamines, where the latter favor the action of inhibition against corrosion. Due to the risk of forming nitrosamines, the use of dialkalonamines for this purpose is less preferred. In contrast, monoalkanolamines or trialkanolamines or, preferably, mixtures thereof are used. In particular, ethanolamines are used. The carboxylic acids which have an anti-corrosion action can be straight or branched chain. Mixtures of different acids can be particularly advantageous. Preferred examples of these carboxylic acids are caprylic acid, ethylhexanoic acid, isononanoic acid and isodecanoic acid. According to another embodiment, the present invention is a water miscible emulsion concentrate containing oil and: from 15 to 30 parts by weight of an oil component; from 30 to 80 parts by weight of the corrosion protection system and emulsifier according to one or both of claims 2 and 3; and, if desired, other auxiliary or active substances.

Such a concentrate can be obtained by adding the number of suitable parts, by weight, of an oily component to the corrosion protection system and emulsifier described above. Of course, it is also possible to produce a concentrate by mixing the oil component, the individual emulsifiers of the emulsifier system and the carboxylic acids in any desired sequence. The carboxylic acids can be used directly as salts. For processing reasons, however, it is more advantageous to mix the acids themselves in the other components and neutralize them by adding alkali metal hydroxide solution, in particular potassium hydroxide solution and / or alkanolamines only once these have been combined with the oil component and the emulsifier system. The apolar or polar oils of a petrochemical or natural origin can be used as the oily component. The synthetic oily components are also suitable. Examples of usable oily components are paraffinic or naphthenic mineral oils, and alkyl ethers having 12 to 20 carbon atoms and / or ester oils. Other optional auxiliary or active substances which may be mentioned are: lubricant additives in general and in particular the so-called 'extreme pressure' additives (known as EP additives), other corrosion inhibitors, such as boric acid or additional alkanolamines, solubilizing agents such as glycols, glycerol or Na eumeno sulfonate. Biocides, which prolong the service life of the emulsion can also be added The present invention also relates to the ready-to-use oil-in-water emulsion obtainable by combining about 0.5 about 10 parts by weight of the above described concentrate with about 99.5 to about 90 parts by weight of water.According to the self-emulsifying characteristics of the emulsion concentrate, the emulsion ready for use is formed in combination with water spontaneously or after a slight mechanical agitation, this emulsion can be used, for mplo as cleaning emulsion, protection against corrosion or refrigerant lubricant. When soft water is used for the preparation, the emulsion has the main advantage over emulsions of the prior art having only a slight tendency to foam. The emulsion can, in this way, be used in spraying processes within the temperature range between the freezing point and the boiling point of the emulsion and does not require a minimum temperature for spray applications. The characteristics of low foam formation are also appreciable in applications such as lubricant cooling emulsion. Although the novel emulsifier system and the emulsions containing it in particular have their advantages in soft water, however, these can also be used in hard water without disadvantage.

Practical examples Some examples of the emulsion concentrates according to the present invention containing the present emulsifier system are mentioned below. These were obtained by stirring the components together in the mentioned sequence. Table 1 shows the emulsion concentrates produced by way of example.

Table 1: Composition (% by weight) of the emulsion concentrates Table 1, continued Pernil RU = distillation residue from the distillation of fatty alcohols. 2) Rhodafac PA35 = oleyl / cetyl alcohol + EO mono / diphosphate, Rhone-Poulenc.

Foaming behavior Using the emulsions produced from the concentrates according to the formulations according to the formulations 1, 2, 3, 4, 8, 9 and 13, 2% by weight of the emulsions were prepared in water with a degree of hardness of 3 ° dH [German hardness]. 10-liter portions of these emulsions were sprayed at a temperature in a range between about 30 and about 45 ° C at a spray pressure of 5 bar for a period of 60 minutes in a spray unit with a single nozzle. The height of the foam, defined as the height of the foam above the liquid level in the initial state, was measured during the operation of the spray unit. In all cases the height of the foam was less than 2 cm.

Comparative tests 100. 00 100.00 100.00 The foaming tests were performed on the spray unit as described for all three formulations (20 g / 1 in water with 3o dH [German hardness]).

Results: The unit stops automatically when it reaches a foam height of 7 cm. The table shows the time until shutdown, (based on this test, none of the formulations can be classified as 'sprayable' or 'low foaming').

Protection against corrosion Using the concentrates according to the formulations 1, 5, 9, 10, 11 and 13, 2.5% by weight of the emulsions were prepared in water with a degree of hardness 3 ° dH [German hardness]. Using these, a corrosion protection test was carried out according to the pieces / filter paper method for the German standard DIN 51 360/2, as is normal for water-cooled lubricant emulsions. For this purpose, pieces of cast iron are moistened on a round filter paper with the emulsion and the room temperature is maintained for 2 hours on a glass disk. The corrosion marks on the filter paper are then visually rated according to the degrees of corrosion from 0 to 4. The degree of corrosion 0 means no corrosion, the degree of corrosion 1 means traces of corrosion, the degree of corrosion 2 means light corrosion, the degree of corrosion 3 means moderate corrosion and the degree of corrosion 4 means severe corrosion. For the emulsions according to formulations 1, 5, 10, 11 and 13 the degree of corrosion was 0 and for the emulsion according to formulation 9 was between 0 and 1. The operation against corrosion was further determined with prepared emulsions from formulations 1, 7 and 13 using a climatic plate test, as is common for corrosion protection emulsions. For this purpose, emulsions of 2% by weight of the mentioned concentrates were prepared in water with a hardness of 23 ° dH [German hardness]. These steel sheets St 1405 were cleaned with degreaser powder and a brush, rinsed in running water and completely deionized water, immersed in ethanol and then dried with degreased compressed air. The leaves were then sprayed with the individual emulsions for 3 minutes at a spray pressure of 3 bar and a temperature of 65 ° C and dried for 2 to 3 hours in a laboratory atmosphere. The leaves are then stored in closed climate cabinets at room temperature and different atmospheric humidity. Corrosion is assessed visually each day during the first week and then twice a week. The test is concluded after 40 days or once 30% surface corrosion is reached. Based on these findings, a corrosion protection value (VPC) is determined using the following method. The higher the value reached, the better the protection against corrosion. The maximum value of 112 indicates maximum protection against corrosion for 40 days. The following method is used to calculate the corrosion protection value, VPC: VPC = A + B + C < 112 Limit value A = without corrosion (0%), no. of days < 12 B = slight corrosion (< 1%), no. of days < 40 C = Ci + C2 bonus < 60 Ci = (number of days up to 30% corrosion) x 0.5 < 20 C2 = bonus per table if the corrosion observed after 40 days is < 30% < 40 Table to determine C2 bonus: Corrosion after 40 days: > 30% - 0 20% - 10 30% - 10 10% - 20 5% - 30 < 1% - 40 Values obtained in the protection against corrosion: Stability of the emulsion Using the concentrates according to formulations 1, 6, 9, 12, 13 and 14, emulsions at 2% by weight were prepared in water with a degree of hardness of 20 ° dH [German hardness]. After 48 hours, the stability of the emulsion was determined in accordance with the German standard DIN 51 367.

Result:

Claims (6)

1. CLAIMS The use of a low foaming emulsifier system consisting of: a) ethoxylated / propoxylated fatty alcohols having from 8 to 18 carbon atoms in the alcohol with from 2 to 6 units of ethylene oxide and from 4 to 8 units of propylene's OXID; and b) fatty and / or propoxylated alcohols of fatty alcohols having from 12 to 24 carbon atoms in the alcohol and from 0 to 3 units of propylene oxide and / or the residue of the distillation of these fatty alcohols; in a weight ratio of a: b from 1: 0.3 to 0.3: 1, for the production of water-miscible emulsion concentrates containing oil and / or oil-in-water emulsions.
2. A corrosion protection and emulsifier system consisting of: 15 to 20 parts by weight of one or more straight or branched chain carboxylic acids having from 6 to 10 carbon atoms or the anions thereof; and from 15 to 40 parts by weight of the emulsifying component composed of: a) ethoxylated / propoxylated fatty alcohols having from 8 to 18 carbon atoms in the alcohol with 2 to 6 units of ethylene oxide and from 4 to 8 units of propylene's OXID; and b) fatty and / or propoxylated alcohols of fatty alcohols having from 12 to 24 carbon atoms in the alcohol and from 0 to 3 units of propylene oxide and / or the residue of the distillation of these fatty alcohols; in a weight ratio of a: b from 1: 0.3 to 0.3: 1.
3. 3. The corrosion protection and emulsifier system according to claim 2, wherein the carboxylic acids are partially or completely present as potassium and / or alkanolammonium salts.
4. 4. The water-miscible emulsion concentrate containing oil and: from 15 to 35 parts by weight of an oil component; from 30 to 80 parts by weight of the corrosion protection system and emulsifier according to one or both of claims 2 and 3.
5. 5. The emulsion concentrate according to claim 4, wherein it contains paraffinic mineral oil or naphthenic, dialkyl ethers having from 1 to 20 carbon atoms and / or ester oils as the oily component.
6. 6. The emulsion concentrate according to one or both of claims 4 and 5, wherein it also contains lubricant additives, EP additives, other corrosion inhibitors and / biocides as auxiliary or active substances. The oil-in-water emulsion obtained by mixing 0.5 to 10 parts by weight of an emulsion concentrate according to one or more of claims 4 to 6 with 99.5 to 90 parts by weight of water. The use of the emulsion according to claim 7 as a cleaning, corrosion protection or refrigerant lubricant emulsion.