EP0015491B1 - Aqueous emulsions for metal working and concentrates for their preparation - Google Patents

Description

The present invention relates to new technical fluids for metalworking.

For metalworking on an industrial scale, certain liquids are required, e.g. B. serve to cool the tool and the machined workpiece and ensure good corrosion protection. Oil-in-water emulsions are generally used as liquids for metalworking. It is important here that the oil is easily emulsifiable and that the emulsion formed is stable and has good corrosion protection and lubrication properties. In addition to water and a mineral oil, such emulsions contain an emulsifier and additives which, among other things, simultaneously improve the lubricating effect and corrosion protection properties. Petroleum sulfonates with an average molecular weight of 400 to 600 are frequently used as emulsifiers and rust preventives in such formulations, but they have a high viscosity and foam strongly, which is not desirable.

It has now been found that emulsions without the above-mentioned tendency to foam can be obtained in a simple manner if all or some of these petroleum sulfonates are replaced by sec alkane sulfonates, the other desired properties to be achieved, in particular stability, cleavability and the anticorrosive Properties depend on the one hand on the ratio of petroleum sulfonates: alkanesulfonates and on the other hand on the content of alkanesulfonates in the emulsion or on a mixture of these salts with petroleum sulfonates. Surprisingly and unexpectedly, a synergistic effect has been found between the petroleum sulfonates and the basic alkane sulfonates, which facilitates the preparation of the emulsion and which makes it possible to suppress foam formation in a wide range and to ensure an anticorrosive effect.

The present invention therefore relates to aqueous emulsions of the oil-in-water type for metalworking, characterized in that they contain a sec. Alkanesulfonate or a mixture of such a salt with petroleum sulfonates in the form of the alkali salt with a molecular weight of 400 to 600 in a ratio of 1: 3 to 3: 1, preferably in a ratio of 1: 1.

The amount of sec. Alkanesulfonate or the mixture of this salt with the petroleum sulfonates in the emulsion is preferably between 0.10 and 2 parts based on 100 parts of the emulsion.

As alkanesulfonic acids, for example, mixtures obtainable according to the processes described by C. Bluestein and BR Bluestein (see Manufacturer Science Series - Volume 7 - Anionic Surfactants - Part 11, pages 331-334 - Marcel Dekker Verlag, New York, 1976) from the sulfonation of (C ₁₀ -C ₁₈ ) paraffins by using sulfuric anhydride in the presence of oxygen under UV radiation. Examples of these are in particular (C ₁₀ -C ₁₈ ) -alkanesulfonic acids with a sulfo group on the second carbon atom. The salts, in particular the sodium and potassium salts, can be obtained by known methods by neutralizing these acids with sodium hydroxide solution or potassium hydroxide solution.

The petroleum sulfonates used are preferably oil-soluble sodium alkylarylsulfonates with one or more alkyl chains, such as the sodium salt of polypropylenebenzenesulfonic acid. These petroleum sulfonates arise, among other things, as by-products in the treatment of petroleum with sulfuric acid.

In addition to the component (s) mentioned above, the emulsions according to the invention naturally contain water, a mineral oil and the constituents customary for such emulsions, such as soaps, fatty acid alkanolamides, alkyl or arylsulfamidocarboxylic acid salts, nonionic surfactants, sodium nitrite, triethanolamine borate or phosphoric acid derivatives.

The present invention further relates to concentrates for the production of the above emulsions with a content of 1 to 10%, preferably 3 to 6%, of these concentrates.

Such concentrates contain 3 to 20% sec. Alkanesulfonates or a mixture of such a salt with petroleum sulfonates in the form of sodium salts, a mineral oil or a spindle oil with or without the additives customary for emulsions.

• 3 bis 20% eines Kaliumalkansulfonats oder eines Gemisches aus diesem Salz mit Petroleumsulfonaten in Form von Natriumsalzen, im Verhältnis 1 : 3 bis 3 : 1, vorzugsweise 1 : 1;
• 30 bis 80% Mineralöl oder Spindelöl;
• 1 bis 10% organische Carbonsäure wie Naphthensäure oder Ölsäure;
• 1 bis 10% nicht-ionische Tenside wie beispielsweise oxäthylierte Nonylphenole, Alkohole oder Fettsäuren;
• 3 bis 25% Fettsäurealkanolamide;
• 3 bis 25% Alkyl- oder Arylsulfamidocarbonsäuresalze und, falls erforderlich,
• 1 bis 30% Chlorparaffine.

The above concentrates preferably contain

• 3 to 20% of a potassium alkanesulfonate or a mixture of this salt with petroleum sulfonates in the form of sodium salts, in a ratio of 1: 3 to 3: 1, preferably 1: 1;
• 30 to 80% mineral oil or spindle oil;
• 1 to 10% organic carboxylic acid such as naphthenic acid or oleic acid;
• 1 to 10% non-ionic surfactants such as, for example, oxyethylated nonylphenols, alcohols or fatty acids;
• 3 to 25% fatty acid alkanolamides;
• 3 to 25% alkyl or arylsulfamidocarboxylic acid salts and, if necessary,
• 1 to 30% chlorinated paraffins.

The main properties of the inventive either used alone or in a mixture Compounds as well as the emulsions and concentrates containing them are evident from Tables I to III below, which illustrate the present invention.

In Tables 1 and II, the values of various physical properties of the concentrates and the emulsions prepared from these concentrates, such as the appearance of the concentrates, as well as the appearance, cleavage, stability, pH, anticorrosive properties (filter paper test) and foaming power of the emulsions, are corresponding the composition by weight of the concentrates according to the invention.

From these tables it can be seen that these properties depend on the concentration of the emulsions, on whether the emulsion contains one or two components and finally on the ratio of the two components in the emulsion.

Table III shows the synergistic effect on the viscosity of the emulsions after combining the alkanesulfonates according to the invention with the petroleum sulfonate. With regard to the cleavability listed in Tables I and II as the physical property of the emulsion, it should be noted that this is a criterion for the dispersibility of the oil phase with simple manual stirring. This property and the stability (in hours) are assessed visually.

The pH of the 3% emulsions is determined using a glass electrode.

• Korrosionsgrad
  

The anticorrosive properties are determined in 20 ° warm water of normal hardness in accordance with DIN 51 360-1 (filter paper test), the degree of corrosion being expressed by the following numbers:

• Degree of corrosion
  

These determinations were carried out on 2- and 3% emulsions.

The foaming power is determined at 25 ± 3 ° C according to Citroen standard LC 1425 as follows: 1 liter of a 3% aqueous emulsion is left for 5 hours by means of a pump at a speed of 250 Vh. circulate. Then let the emulsion flow through a nozzle with an inner diameter of 5 mm from a height of 75 mm into a test tube of 2 liters with a diameter of 80 mm and lead it back through a nozzle at the bottom of the test tube. After the pump has been turned off, measure the volume of the liquid in the test tube after 5 hours (1000 indicates that there is no foaming). The foaming power is given in cm ₃ .

The viscosity values in Table 111 above are given in millipascal seconds (mPas). They were determined at 50 ° C using a Brookfield viscometer, type RVT with a No. 5 rotor and a speed of 10 revolutions per minute. The values obtained show a clear drop in viscosity when mixtures are used.

Claims (8)

1. Aqueous emulsions of the oil-in-water type for metal processing, characterized in that they contain at least from 0.1 to 2 parts, relative to 100 parts of the emulsion, of a secondary C₁₀-C₁₈-alkane sulfonate, or a mixture of such a salt with petroleum sulfonates in the form of their alkali metal salts having a molecular weight of from 400 to 600, in a ratio of from 1 : 3 to 3 : 1, preferably in a ratio of 1 : 1.

2. Aqueous emulsions as claimed in Claim 1, characterized in that they contain as alkane sulfonates the potassium or sodium salts thereof.

3. Aqueous emulsions as claimed in Claim 1, characterized in that they contain as petroleum sulfonates oil-soluble sodium alkylaryl sulfonates having one or more alkyl chains.

4. Aqueous emulsions as claimed in Claim 3, characterized in that they contain as petroleum sulfonate sodium polypropylbenzene sulfonate.

5. Aqueous emulsions as claimed in Claims 1 to 4, characterized in that they contain water, a mineral oil and the components usual for such emulsions such as soaps, fatty acid alkanolamides, alylsulfamidocarboxylic acid salts, nonionic surfactants, sodium nitrite, triethanolamine borate or phosphorus acid derivatives.

6. Concentrates for the preparation of the emulsions as claimed in Claims 1 to 5, characterized in that they contain from 3 to 15% of the above salts, a mineral oil or a spindle oil, with or without the additives usual for the preparation of these emulsions.

7. Concentrates as claimed in Claim 6, characterized in that they contain

3 to 20% of a potassium alkane sulfonate or a mixture of such a salt with petroleum sulfonates in the form of the sodium salt, in a ratio of 1 : 3 to 3 : 1, preferably 1 : 1,

30 to 80% of a mineral oil or a spindle oil,

1 to 10% of organic carboxylic acids,

1 to 10% of nonionic surfactants,

3 to 25% of fatty acid alkanolamides,

3 to 25% of alkyl- or arylsulfamidocarboxylic acid salts, and, if necessary,

1 to 30% of chlorinated paraffins.

8. Emulsions as claimed in Claims 1 to 5, characterized in that they contain from 1 to 10%, preferably 3 to 6% of a concentrate as claimed in Claims 6 or 7.