SE415107B - METAL WORKING EMULSION CONTAINING TRIGLYCERID OIL - Google Patents

Description

'7802533-5' I ..- skin contact and risk of lung damage if inhaled oily air. In recent years, the presence of carcinogenic substances in cutting fluids has been reported from several sources. Mineral oil contains polyaromatic hydrocarbons, e.g. bone spurs. In addition, due to the high temperatures prevailing in the cutting zone, it is likely that polyaromatics will be formed when the products are used.

Environmental legislation places great demands on the engineering industry's wastewater management. The technology for purifying spent emulsions and degreasing baths has become complicated, due to the fact that product development has led to more and more additives and increasingly stable surfactant systems.

This has meant that the disposal of consumed cutting fluids, mainly emulsions, has become very cumbersome and expensive.

The smaller companies have to use specialized destruction companies, and only the largest companies have their own emulsion fracturing plants, which, however, do not always work satisfactorily. The separation results in an aqueous phase, which must be further treated in a conventional treatment plant, as well as an oily sludge, which must be deposited, or is at best useful as fuel. A reuse of the oil is unthinkable.

From the industry's point of view, there is thus a great deal of interest in a new type of cutting fluid, and the requirements for such a comprehensive: - be minimally harmful to humans and the environment '- provide minimal formation of oil fumes and oil mist - enable simple waste management without disposal problems - be simple with few additives - be resistant to attack by microorganisms.

Feta oils, i.e. vegetable or animal oils and fats, are functionally suitable raw materials for lubricants, and have previously been used extensively, before the cheaper mineral oils came to completely dominate the market. In contrast to mineral oils, fatty oils are renewable, environmentally friendly and biodegradable.

When cutting metal, it is usually most advantageous to use a cutting fluid in the form of an aqueous emulsion, of the type oil-in-water, whereby a better cooling effect is achieved, while the lubricating moisture of the oil part remains. In addition, from an economic point of view, the use of an aqueous emulsion is considerably more favorable. Although these emulsions can be prepared in a ready-to-use condition, from the point of view of transport and handling it is more convenient to first prepare a concentrate which can then be easily diluted with water at the user - the engineering industry. U The requirements for such a concentrated emulsion are that the stability should be very good, at the same time as it should be easily and indefinitely dilutable with water, and stable as an emulsion even in diluted condition. In order to be able to prepare such an emulsion, special emulsifiers (surfactants) must be used. You can use strong synthetic surfactants, but due to the health and environmental problems that were initially touched on, you want to avoid this.

The object of the present invention has thus been to prepare a metal-working emulsion of the type oil-in-water, based on triglyceride oils, which meets the requirements for stability and dilutability, and which at the same time has sufficiently good and lubricating properties, as used today, but from environmental and health point of view undesirable, products.

It has now surprisingly been found that, from triglyceride oils, an emulsion which satisfies the stability and diluence screw can be prepared by means of an emulsifier system consisting of fatty acid monoglycerides and alkali metal soaps of fatty acids. By using only "natural" and completely harmless components, the requirements placed on the product from an environmental and health point of view are met.

However, in order for the lubricating and cooling properties of the emulsion to be on a par with the mineral oil-based products, the introduction of additional components is required.

Thus, it has been found that the use of an organic amine, such as an alkanolamine, e.g. triethanolamine or a fatty amine, significantly increases the wetting properties of the emulsion, and thus its cooling effect. It has further been found that the addition of free fatty acid to triglyceride oil increases its lubricating properties. In fact, amine and fatty acid are predominantly in starvation form, i.e. The invention is thus characterized in that the metalworking emulsion contains an oil phase and an aqueous phase, and that the oil phase, which consists of: 0.5 -50 parts by weight of triglyceride oil, 0.1 -10 parts by weight of fatty acid monoglyceride, 0.05 -10 parts by weight of fatty acid and 0.05-10 parts by weight of alkanolamine or fatty amine are emulsified into the aqueous phase, which consists of: 0.05-3 parts by weight of alkali soaps of fatty acids and 45 -98 parts by weight of water.

The higher amounts of fat components are used in the preparation of the emulsion concentrates which, as previously mentioned, are usually prepared by the manufacturer, while the lower amounts are used in the preparation of ready-to-use emulsions.

In the preparation of the oil phase, the fatty acid monoglyceride, fatty acid and amine are dissolved in the triglyceride oil at a temperature of 40-70 ° C.

The aqueous phase is prepared by dissolving the alkali soaps at a temperature of zo-70 ° C, combined with zo-40 ° C.

The oil phase is slowly mixed into the aqueous phase with stirring at a temperature of 20-50 ° C.

In the preparation of ready-to-use emulsions, a more vigorous stirring is then sufficient to obtain a stable emulsion, while in the preparation of emulsion concentrate a homogenization of the product is usually required. The homogenization is conveniently carried out at a temperature of 40-60 ° C in conventional homogenization equipment.

The triglyceride oil can be any animal or vegetable oil, or oil mixture, which has a sufficiently low solidification point, to allow a safe handling of the emulsion in both concentrated and ready-to-use form, but which is at the same time reasonably free from mainly linolenic acid, which can otherwise cause oxidation and polymerization problems. Thus, the oil should preferably be liquid at room temperature, and have an oleic acid content of at least 40%. Particularly suitable oils from a functional point of view are olive oil, peanut oil 7802533-5 and lobra oil (rapeseed oil with a low erucic acid content). Also the bottom fractions of fractionated fats, such as e.g. "palmolein" has proven excellent for the purpose.

The fatty acid monoglyceride should be of the "soft product", i.e. have a melting point below 60 ° C. The best product is pure oleic acid monoglyceride (monooleoglycerol), but other commercial products can also be used, such as e.g. Dimodan S, a molecularly distilled monoglyceride, produced by Grindstedvaerket, Denmark, from edible, refined lard, having an approximate fatty acid composition of 30% palmitic acid, 18% stearic acid and 40% oleic acid.

It is also possible to use so-called technical monoglycerides, produced by glycerolysis (glycerol esterification) of e.g. lobra oil.

Such products, with a content of 40-60% monoglyceride, are easy to produce without complicated equipment, and thus attractive. Of course, if such products are used, the amount ratio of triglyceride-oil to glycerolysis product must be adjusted so that the content of monoglyceride in the emulsion is correct.

The oil-soluble monoglyceride was used, primarily because of its surfactant properties, as the lipophilic component. the emulsifier system.

However, the surface activity also has a wetting effect, whereby the lubricating effect of the oil increases.

The fatty acid is suitably constituted by oleic acid. The requirements for this component are the same as for the oil and monoglyceride, namely that it is liquid at room temperature, ie has a titer lower than Z5 ° C, and that it does not contain significant quantities of more unsaturated homologues.

The fatty acid has been shown to significantly contribute to an increased lubricating effect.

The presence of fatty acid prevents the appearance of odor during harder processing operations, which can partly be assumed to be due to the fatty acid's improvement of the lubricating effect, and partly related to the formation of soaps of amine and fatty acid.

As the alkanolamine, an amine having 2-4 carbon atoms in the alkanol is suitably used. Particularly suitable is triethanolamine, which in addition to its good wetting and anti-corrosion properties also has the advantage of being dermatologically harmless, which is also shown by its widespread use in cosmetic preparations. 7802533-5 6 The amine can also be based on fat raw material; whereby the same good wetting and anti-corrosion properties can be achieved. Suitably a fatty amine having 8 to 18 carbon atoms in the chain can be used, and dodecylamine is considered to be particularly suitable. The fatty acid soap is suitably a sodium or potassium salt of a fatty acid having 12-22 carbon atoms, usually 16 or 18 carbon atoms (palmitic or stearic acid). Potassium stearate gives slightly better results than sodium stearate, but in general, if stearin soaps are to be used, deionized water must be used to prevent the accumulation of calcium and magnesium soaps. When using oleic acid soaps (sodium or potassium) this problem is completely avoided, although it is most convenient to use deionized water when preparing the concentrate.

In machining operations with particularly high contact pressures, the lubricating properties of the metal working emulsion can, if necessary, be further enhanced by the addition of lightly chlorinated and / or sulfurized triglyceride oils. These agents are well compatible with the metalworking emulsion of the invention. Preferably, in particularly demanding processes, 20-40% of the triglyceride oil is replaced with such agents.

To prevent oxidation and polymerization problems, an antioxidant may be added. Suitable antioxidants are butylhydroxyanisole, BHA, and butylhydroxytoluene, BHT. Advantageously, e.g. Eastman Kodak's products Tenox 2 or Tenox 6 are used. These agents are suitably added in an amount of 0.1-1.0% by weight in the concentrated emulsion.

Under the adverse conditions of the workshop environment, micro-organisms can be easily attacked. If these microorganisms develop uninhibited for a long time, an unpleasant odor can develop, at the same time as the emulsion's corrosion-inhibiting properties are reduced, through the formation of acidic decomposition products, similar to what takes place when using traditional mineral oil-based products.

This is avoided by adding a bactericidal agent to the metalworking emulsion. Advantageously, a formaldehyde cleaving agent can be used, e.g. Grotan BK, manufactured by Schülke & Mayr GmbH. I I 7802533-s L The product produced according to the invention thus offers from the user's point of view a wide range of advantages: The product has been based in its entirety on fatty oils or constituents thereof. These oils are renewable, environmentally friendly and biodegradable.

The presence of skin irritations, eczema and allergies can be significantly eliminated, and the risk of cancer eliminated.

Due to the greater molecular weight of the triglyceride oils, and the associated significantly higher vapor pressure, no troublesome oil fumes will occur. In general, this means a considerably cleaner working environment. 'Products based on fatty oils do not present any difficulties from a waste management point of view. With the right separation technique chosen, the oily part can be easily separated, and the water part does not require any special treatment before discharge. The fatty part can be easily hydrolytically decomposed with known technology, and the fatty acids thus obtained are reused.

The invention is further illustrated in the following examples: Example 1. Preparation of a metalworking emulsion in concentrated form.

Oil phase 34.7 parts by weight palmolein 4.9 parts by weight of monoglyceride, Dimodan S 2.7 parts by weight of rapeseed fatty acids 2.7 parts by weight of triethanolamine Aqueous phase: 1.1 parts by weight of sodium oleate 55.0 parts by weight of deionized water.

The palm oil consisted of a bottom fraction from palm oil fractionation.

The palm oil content of oleic acid was 50%.

The components of the oil phase were mixed at 60-7006. The soap was dissolved in the water at ZSOC, after which the oil phase was slowly and with stirring the aqueous phase was added. The dispersion thus obtained was then homogenized at 50 ° C in a conventional type homogenizer. '7802533-5 e The emulsion concentrate was easily and indefinitely dilutable with water of varying hardness (0-12 dH). Both the emulsion concentrate and the diluted emulsions were found to be storage stable with no tendency to oil separation.

The product was tested in dilution 1:10 in a multi-spindle drilling machine in production operation where the work operation was threading in aluminum. After 1 month of operation, the function of the emulsion was unchanged, and completely comparable to the function of a conventional mineral oil-based emulsion.

Example 2. A metalworking emulsion was prepared for testing in a heavily loaded, numerically controlled automatic lathe. The machining took place with cemented carbide inserts in a number of ferrous metals such as e.g. cast iron and hardened tool steel. The metalworking emulsion was prepared as follows: Oil phase 27.9 parts by weight of rapeseed oil 11.7 parts by weight technical monoglyceride of rapeseed oil 2.7 parts by weight of rapeseed fatty acid 2.7 parts by weight of triethanolamine 0.4 parts by weight of antioxidant, Tenox 6 Aqueous phase: 1.1 parts by weight of sodium part .

The rapeseed oil was of the lower uka acid type with an oleic acid content of 52%.

The technical monoglyceride had a content of 40% monoglyceride.

The components of the oil phase were mixed at a temperature of 40-50 ° C, and the sodium oleate was dissolved in the water at a temperature of 25-SOOC. Then the oil phase was added slowly, and with stirring to the water phase. The resulting dispersion was homogenized at 50 ° C in conventional homogenization equipment.

The emulsion concentrate thus obtained was diluted 1: 15 in ordinary city water and tested in an automatic lathe. After 3 months of operation, the function of the metalworking emulsion was unchanged. The machined details did not show any corrosion tendencies. The metalworking emulsion did not give drying coatings, on the contrary, e.g. machine surfaces very easy to pour clean. '7802533-5 u Example 3. The example is intended to show the lubricating function of the fatty acid in the emulsion.

Two metalworking emulsions in ready-to-use concentration were prepared for testing in a circular grinder. The metalworking emulsions were made from the following components: Sample A parts by weight Sample B parts by weight Oil phase Oil phase: rapeseed oil 2.00 rapeseed oil 1.80 technical monoglyceride technical monoglyceride of rapeseed oil 0.78 of rapeseed oil 0.78 triethanolamine 0.18 rapeseed fatty acids 0.20 Z triethanolamine .18 Aqueous phase: Aqueous phase: sodium stearate 0.10 sodium stearate 0.10 deionized water 97 deionized water 97 Rapeseed oil was of the lower uka acid type with an oleic acid content of 60%.

The technical monoglyceride had a content of 40% monoglyceride.

The components of the oil phase were mixed at 40-50 ° C and the sodium stearate was dissolved in the aqueous phase at 60-70 ° C. Thereafter, the oil phase was slowly added to the aqueous phase with vigorous stirring to obtain a stable emulsion.

The metalworking emulsions prepared in this way were tested in a circular grinder by insert grinding in hardened tool steel.

It was found that with regard to the surface finish of the processed material, as well as relative grinding wheel wear, sample B (with fatty acid addition) gave better results than sample A (without fatty acid addition). On average, the surface finish was 10% better and the relative grinding wheel wear was 30% lower with sample B than with sample A. The results were completely comparable to those obtained when conventional mineral oil-based emulsions without EP additives are used.

Example 4. The example is intended to show the wetting-improving function of triethanolamine in the emulsion.

Two emulsion samples were prepared according to the same procedure as in Example 3. '7802533-5 Sample A parts by weight Sample B parts by weight Oil phase: Oilfusz rapeseed oil 3.50 rapeseed oil 4.00 monoglyceride of oil monoglyceride of oleic acid 1.00 acid 1, 00 triethanolamine 0.50 Aqueous phase: ~ Aqueous phase: sodium stearate 0.10 sodium stearate 0.10 deionized water 95 deionized water 95 Rapeseed oil was of the lower uka acid type with an oleic acid content of 60%.

Measurements were made of these emulsion-massive wetting of steel surfaces. Emulsion sample B (without triethanolamine) was found to give a wetting angle of 40-450, and emulsion sample A (with triethanolamine) to give a wetting angle of 15-ZOO. This latter result was t.o.m. slightly better than that obtained with conventional mineral oil-based emulsions.

Example 5. A metalworking emulsion was prepared according to Example 1 with the following ingredients: Oil phase 34.3 parts by weight of palmolein 4.8 parts by weight of monoglyceride Dimodan S 2 7 parts by weight of rapeseed fatty acids 5.4 parts by weight of triethanolamine Water phase: 11 parts by weight of sodium molar and threading. In the machine, toughened steel was machined with high-speed steel tools. The processing results were compared with those obtained when a traditional emulsion-type cutting fluid with the addition of EP additives was used. The traditional cutting fluid was especially intended for heavy machining such as drilling, threading, thread cutting and drawing in various iron materials.

Both cutting fluids were used in the same dilution, about 15 times, with ordinary tap water. The surface smoothness of the processed material was the same for the traditional cutting fluid and for the cutting fluid according to the invention. The tool life was as good when drilling and when threading up to and including slightly better with the cutting fluid according to the invention than with the traditional cutting fluid.

Claims (1)

Claims Metal working emulsion of the oil in water type, with good stability and unlimited dilutability, based on triglyceride oils, which emulsion is intended to be used in deforming metal working, mainly chip-separating processing, but also suitable for pressing and rolling, characterized in that it consists of an oil phase dispersed in a continuous aqueous phase and that the oil phase consists of: 0.5 -50 parts by weight of triglyceride oil 0.1 -10 parts by weight of fatty acid monoglyceride 0.05-10 parts by weight of fatty acid, and 0.05-10 parts by weight of alkanolamine or fatty amine, And that Vâttè fl get b6SïåT QVI -v 0.05- J parts by weight of alkali soaps of fatty acids, and 45 -98 parts by weight of water. Metalworking emulsion according to claim 1, in concentrated form, characterized in that the oil phase consists of: 1 'parts by weight of triglyceride oil, 2-10 parts by weight of fatty acid monoglyceride, 1-10 parts by weight of fatty acid and 1-10 parts by weight of alkanolamine or fatty amine, * and aqueous of: 0.5- 3 parts by weight of alkali soap of fatty acids and 45-60 parts by weight of water. Metalworking emulsion according to claim 1 in ready-to-use form, characterized in that the oil phase consists of: 0.5 -10 parts by weight of triglyceride oil, 0.1 - 2 parts by weight of fatty acid monoglyceride, 0.05- 2 parts by weight of fatty acid and 0.05- 1 parts by weight of alkanolamine or 8 0.5 parts by weight of alkali soap of fatty acids and 90 -98 parts by weight of water. Metal processing emulsion according to claim 1, characterized in that the triglyceride oil consists of a fatty oil, liquid at room temperature, and with a cleic acid content (Cl8: 1) of at least 45% by weight, such as: olive oil, peanut oil and camphoric acid rapeseed oil, and the bottom fractions of fractionated fats, such as palmolein or animal oleins. Metalworking emulsion according to claim 1, characterized in that the fatty acids in the fatty acid monoglyceride consist of fatty acids having 16 and / or 18 carbon atoms, of which at least 40% by weight consist of oleic acid (C18: 1), preferably pure oleic acid monoglyceride. A metalworking emulsion according to claim 1, characterized in that a technical product obtained by fatty acid monoglyceride is obtained, obtained by glycrole esterification of a triglyceride oil according to claim 4. A metalworking emulsion according to claim 1, characterized in that a fatty acid ° C, and preferably consists of oleic acid. Metalworking emulsion according to claim 1, characterized in that the alkanolamine is preferably triethanolamine, or that the fatty amine is preferably a dodecylamine. Metalworking emulsion according to claim 1, characterized in that the alkali soap of fatty acids consists of sodium or potassium soap of fatty acids with a titer lower than ZSOC, and preferably consists of sodium or potassium oleate. Metalworking emulsion according to claim 1, characterized in that possibly 20-40% by weight of the triglyceride oil has been replaced by an agent for high contact pressure, which consists of a lightly chlorinated or sulfurized triglyceride oil. STATED PUBLICATIONS: Sweden 384 523 (c1om 1/40) Great Britain 1,025 240 (23 c: 1/04) us 2 258 552 (252-49.3)