EP0826761A1 - Use of polyhydroxycarboxylic acid amides as EP-additives - Google Patents

Abstract

Use of polyhydroxycarboxylic acid amides as high pressure additives, especially for lubricants, metal working fluids and, hydraulic fluids is new.

Description

The invention relates to the use of polyhydroxycarboxamides as a high pressure additive, especially for lubricants, Metalworking fluids and hydraulic fluids.

High pressure additives, also internationally in the professional world "EP-Additive" (Extreme-Pressure-Additives) fluids, e.g. Gear oils, motor oils, metalworking oils and hydraulic fluids added to to give them a high load capacity, which when transmitting large forces is necessary to avoid that touching metal surfaces weld together and are subject to uncontrolled wear.

Lubricant additives are known from US Pat. No. 4,647,389, which are prepared by reacting a natural oil, for example coconut oil or palm oil, with a C ₂ -C ₁₀ -hydroxy acid and a polyamine. These are hydroxyacylated fatty acid amides of polyamines, which act as friction modifiers in lubricating oil compositions, but not as EP additives.

U.S. Patent 4,512,903 discloses hydroxyacylated amides from primary and secondary fatty acid amines as lubricant additives known, which also act as a coefficient of friction, but not as EP additives.

Commonly used as high pressure additives Sulfur compounds that unite under high pressure conditions Form sulfide film, chlorine compounds, phosphorus compounds, organic nitrogen compounds and metal soaps like Zinc stearate is used (cf. Ullmanns Encyklopadie der technical chemistry, 4th edition, 1981, volume 20, p. 552 ff.).

Although all of these classes of compounds are quite effective high-pressure additives dispense, they have a wide variety "Side effects" which are undesirable depending on the application are. For example, sulfur and chlorine compounds chemical compared to most metallic materials aggressive, but at the same time also wastewater and thus polluting the environment. Metal soaps such as zinc stearate also lead to wastewater contaminated with heavy metals, the complex cleaning process have to be subjected. Finally, phosphates favor bacterial growth, which in particular Hydraulic fluids are extremely dangerous because of bacterial growth the rheological properties of the oils or Emulsions changed, causing the systems to collapse can lead.

For all of these reasons, there is still a strong one Need to provide the specialist with further resources, which can be used as a high pressure additive or EP additive, and such agents and compounds that are non-toxic, which do not represent a burden on the wastewater and thus are environmentally friendly, especially no heavy metals or heavy metal ions, no toxic gases such as hydrogen sulfide and no strong acids such as hydrogen chloride or Release hydrochloric acid or sulfur dioxide or sulfuric acid, which nevertheless has excellent lubricating properties and Have friction wear values.

It has now surprisingly been found that polyhydroxycarboxamides, the so far as sugar substitutes and dietary nutrients have been used as a high pressure additive (EP additive), especially for lubricants, metalworking oils and hydraulic fluids can be used can. These polyhydroxycarboxamides are known, e.g. from international patent application PCT / US91 / 07534 as WO 92/06601.

The amides which can be used according to the invention as EP additive of Polyhydroxycarboxylic acids, especially sugar acids with 5 to 7 carbon atoms, particularly preferably gluconic acid and glucoheptonic acid, can be N-unsubstituted amides, however, they are preferably N-substituted Amides, especially alkyl and dialkyl amides with alkyl radicals with 1 to 4 carbon atoms, as well as monohydroxyalkylamides and polyhydroxyalkylamides, aminoalkylamides and aminohydroxyalkylamides, in each case the respective Alkyl radical has 1 to 4 carbon atoms.

Polyhydroxycarboxamides which are particularly preferred according to the invention are:

N, N-dimethyl-gluconamide, N- [2- (hydroxyethyl)] - gluconamide, N- [2- (aminoethyl)] - gluconamide, N- [2- (hydroxypropyl)] - gluconamide, N- [1,2-dihydroxypropyl] gluconamide, N, N-dimethylglucoheptonamide, N- [2- (hydroxyethyl)] glucoheptonamide, N- [2- (aminoethyl)] - glucoheptonamide, N- [2- (hydroxypropyl)] - glucoheptonamide and N- [1,2-dihydroxypropyl] glucoheptonamide.

At least one of the polyhydroxycarboxamides is preferred in an oily or aqueous composition included, e.g. in a lubricant, an engine or Gear oil, a metalworking oil or metalworking fluid or a hydraulic fluid, these Fluids also in the form of an emulsion, e.g. a water-in-oil emulsion or an oil-in-water emulsion.

Such an oily or aqueous composition preferably contains still at least one anti-corrosion agent, wherein Boric acid esters are particularly preferred as corrosion inhibitors are. In addition, the composition can at least contain an emulsifier.

Simultaneous use has proven to be particularly advantageous one of the polyhydroxycarboxamides mentioned and proven at least one polyalkylene glycol: the under Using such a combined additive measured Reichert friction wear values clearly indicate one synergistic effect, which results in simultaneous use one of the amides mentioned and a polyalkylene glycol sets. A scientific explanation for this There is currently no effect.

The at least one polyhydroxycarboxamide is preferred used in such an amount that the amide content up to 70% by weight of the respective composition. Prefers however, the composition is applied diluted with water, wherein the amide content 0.01 to 3.0 wt .-% of the respective Composition.

The polyhydroxycarboxamides used are chiral Compounds that have at least one asymmetric carbon atom own and therefore in the form of enantiomers and in Form of racemates can be present. The most preferred Gluconamides and glucoheptonamides can therefore be found in the D- or L-form or as a D, L-racemate.

The invention further relates to a high-pressure additive (EP additive), especially for lubricants, metalworking fluids and hydraulic fluids that are at least one Contains amide of a polyhydroxycarboxylic acid, but preferably additionally at least one anti-corrosion agent and / or contains at least one emulsifier.

It can be any of the usual ones known for this purpose Emulsifier and any usual and for this purpose known anti-corrosion agents act, provided that these additional agents with the polyhydroxycarboxamides are chemically compatible, what by simple, the Preliminary tests familiar to a specialist can be determined quickly can.

The additive according to the invention particularly preferably contains additionally at least one polyalkylene glycol, e.g. Diethylene glycol, polyethylene oxide and / or polypropylene oxide or similar.

The proportion of the at least one amide is preferred 0.01 to 70 wt .-% of the high pressure additive.

The additive according to the invention preferably contains one of the the aforementioned gluconamides or glucoheptonamides.

The polyhydroxycarboxamides used according to the invention can be produced as in the publication WO 92/06601. The preparation of N-2- (hydroxyethyl)] - D-gluconamide can be done, for example, that one mole of D (+) - gluconolactone, which is insoluble in methanol, Methanol is added and heated to 65 ° C with stirring becomes. The suspension of the lactone slowly becomes 1 mol ethanolamine, which is dissolved in methanol, added. It takes place a spontaneous exothermic reaction takes place during its course the gluconolactone dissolves completely. About amide formation To complete, reflux is continued for two hours touched. Then the solution is slowly becoming permanent Stirred cooled, whereby the solid amide precipitates out of the solution. The solution is then filtered and the residue washed twice with methanol. Yield: 95% pure N- [2- (hydroxyethyl)] - D-gluconamide, hereinafter referred to as "HEGA".

The EP additive properties of HEGA were determined using the Reichert friction wear tests determined and checked. For this the additive was commercially available in proportions of 5, 10 and 20% by weight Metal working fluids with the designations "Cool 1", "Cool 10" and "Cool Syn 100" added.

"Cool 1" is an emulsion based on mineral oil that contains 15% Mineral oil, anti-corrosion agents (boric acid esters) and emulsifiers contains.

"Cool 10" is an ester-based cutting oil, containing 10% Esters, emulsified in water, as well as corrosion inhibitors and Emulsifiers.

"Cool Syn 100" is an aqueous system based on polyalkylene glycol with anti-corrosion agents, but without emulsifiers.

The Reichert Friction Wear Test is carried out as follows: A roller or roller made of metal is firmly against a rotating sliding ring pressed, the lower third immersed in the fluid to be examined. The speed of rotation the slide ring is set so that the Contact point and thus the point of friction Abrasion between roller and slide ring from the fluid whose Load capacity should be tested, achieved and is wetted. When the slide ring rotates on the Roll elliptical abrasion surfaces, the size of which depends on the load capacity depends on the fluid to be tested. The smaller the abrasion surface after a defined time or after a defined distance, the greater the load bearing capacity. In addition to the abrasion surface, which after a circular route of 100 m is measured, the noise distance sets another parameter that is used in the Reichert friction wear test is measured. When the slide ring starts to move is initially a grinding, metallic Noise until a reaction film is formed from the fluid to be tested has formed between the slide ring and roller. The Orbital distance covered by the slide ring up to this noise suddenly stops, is called a "noise route" designated. The shorter this route, the better the fluid is suitable as an EP additive. When using pure Water does not form a reaction film, so the noise can be heard over the entire test distance of 100 m.

Tables 1 and 2 below are seven examples listed for metalworking fluids to which the amide HEGA added in different amounts as an EP additive has been. Example 1 consists of 95% by weight of Cool 1 and 5% by weight HEGA, example 2 from 90% by weight Cool 1 and 10% by weight HEGA, example 3 consists of 95% by weight of Cool 10 and 5% by weight of HEGA, example 4 from 90% by weight of Cool 10 and 10% by weight of HEGA, example 5 from 95% by weight of Cool Syn 100 and 5% by weight of HEGA, example 6 from 90% by weight of Cool Syn 100 and 10% by weight of HEGA and Example 7 from 80% by weight of Cool Syn 100 and 20 wt% HEGA.

1. Die Löslichkeit des Amids HEGA in den Metallbearbeitungsfluiden Cool 1, Cool 10 bzw. Cool Syn 100. Die Löslichkeit ist in allen sieben Fällen gut (g).

2. Die Veränderung des Fluids infolge des Amidzusatzes. Bei allen sieben Beispielen konnte keine Veränderung festgestellt werden.

3. Die Löslichkeit in den verwendeten Fluiden. Das wasserlösliche HEGA löste sich vollständig in allen Systemen.

4. Die Beständigkeit der Emulsion. Sie entsprach in allen sieben Beispielen den Anforderungen (i.O. = in Ordnung).

5. Der pH-Wert in wäßriger Verdünnung (1:10).

6. Der pH-Wert in wäßriger Verdünnung (1:20).

7. Die Rostschutzwirkung in 2%iger Verdünnung.

8. Die Rostschutzwirkung in 3%iger Verdünnung.

9. Der Reichert-Reibverschleiß-Wert (RRV) in 2%iger Verdünnung; Abriebfläche in mm².

10. Der Reichert-Reibverschleiß-Wert (RRV) in 3%iger Verdünnung; Abriebfläche in mm².

The following technical data are given in Table 2 for each of these seven examples:

1. The solubility of the amide HEGA in the metalworking fluids Cool 1, Cool 10 and Cool Syn 100. The solubility is good in all seven cases (g).

2. The change in the fluid due to the addition of amide. No change was found in all seven examples.

3. The solubility in the fluids used. The water-soluble HEGA completely dissolved in all systems.

4. The stability of the emulsion. It met the requirements in all seven examples (OK = OK).

5. The pH in aqueous dilution (1:10).

6. The pH in aqueous dilution (1:20).

7. The rust protection effect in 2% dilution.

8. The rust protection effect in 3% dilution.

9. The Reichert Friction Wear Value (RRV) in 2% dilution; Abrasion area in mm ² .

10. The Reichert Friction Wear Value (RRV) in 3% dilution; Abrasion area in mm ² .

In particular, the comparison of the RRV values for Examples 1 to 4 on the one hand and Examples 5 to 7 on the other shows that the simultaneous presence of the polyhydroxycarboxamide HEGA and a polyalkylene glycol into one significant decrease in RRV values by at least 50%.

With the EP additive N- [2- (hydroxyethyl)] - D-gluconamide (HEGA) according to the invention in different concentrations and compositions, further Reichert attrition tests were carried out, the results of which are given in Table 3 below. The noise distance, the abrasion area and the bath temperature were measured for the different fluids. For comparison with the EP additive according to the invention, pure water and a 5% aqueous solution of a standard additive, namely boric acid amide, were used. The HEGA according to the invention was also used in aqueous solution, in concentrations of 5, 10, 20 and 30%, without further additives. A test was carried out with a composition of 2.5% HEGA, 82.5% water and 15% known corrosion protection agents and emulsifiers. As can be seen from Table 3, both the noise distance and the abrasion area drop to 14 m or 12 mm ² even at a very low concentration of 5% HEGA. An increase in the concentration from 5 to 10% HEGA leads to a further reduction in the noise distance to 10 m, while the abrasion area remains the same at 12 mm ² . A further increase in the HEGA concentration to 20 or 30% only slightly improves the noise path and the abrasion area. It follows that the effect achieved with the use of polyhydroxycarboxamides according to the invention occurs even at very low concentrations and that an increase in the concentration is in most cases not economically sensible since the best compromise between cost and benefit is achieved even at the lowest concentrations. This is of great importance for the technical use of the EP additives according to the invention.

The best results, namely the shortest noise distance of 7 m and the smallest abrasion area of 9 mm ² , are achieved by combining the smallest amounts of HEGA (2.5%) with known corrosion protection agents such as boric acid esters or polyalkylene glycols. This synergistic effect, which is completely surprising for experts, makes the use of polyhydroxycarboxamides as EP additives particularly attractive, both in technical and in economic terms.

The use according to the invention of polyhydroxycarboxamides as EP additives thus offers the following advantages: the additives used are readily biodegradable, they are water-soluble, so that, as a rule, neither emulsifiers nor anti-foaming agents are necessary, they are inherently non-foaming, and they are particularly easy to use for the processing of iron and ferrous metals and they are non-toxic, as is shown in particular by their known use as sugar substitutes and dietary nutrients. The amides used according to the invention can be used in anhydrous but also in aqueous metalworking fluids, in hydraulic fluids, in textile machining fluids and in fluids for cutting and grinding metals and glass. Example No. 1 2nd 3rd 4th 5 6 7 Cool 1 95.0 90.0 HEGA 5.0 10.0 Cool 10 95.0 90.0 HEGA 5.0 10.0 Cool Syn 100 95.0 90.0 80.0 % HEGA 5.0 10.0 20.0 % 100 100 100 100 100 100 100 % Example No. 1 2nd 3rd 4th 5 6 7 Solubility in the concentrate G G G G G G G Change in concentrate 0 0 0 0 0 0 0 solubility OK OK OK OK OK OK OK Resistance of the emulsion OK OK OK OK OK OK OK pH 1:10 9.4 9.4 9.5 9.5 9.5 9.5 9.5 pH 1:20 9.3 9.3 9.4 9.4 9.4 9.3 9.2 Rust protection 2% OK OK OK OK OK OK OK 3% rust protection OK OK OK OK OK OK OK RRV 2% [mm ² ] 22.4 18.3 22.8 17.8 12.2 9.8 7.6 RRV 3% [mm ² ] 20.6 17.1 20.4 19.7 10.0 7.9 7.0 medium Noise distance [m] Abrasion area [mm ² ] Bath temperature [° C] water 100 38 70 5% HEGA 14 12th 40 95% water 10% HEGA 10th 12th 34 20% HEGA 9 10th 34 30% HEGA 8th 10th 33 2.5% HEGA 7 9 36 15% additives 5% standard amide (comparison) 14 28 50

Claims (16)

Use of polyhydroxycarboxamides as high pressure additive (EP additive), especially for lubricants, Metalworking fluids and hydraulic fluids. Use according to claim 1, wherein the amides are selected are from the group of alkylamides, dialkylamides, monohydroxyalkylamides, Polyhydroxyalkylamides, aminoalkylamides and amino-hydroxy-alkylamides, in which the respective alkyl radical always has 1 to 4 carbon atoms. Use according to claim 1 or 2, wherein the polyhydroxycarboxylic acids Sugar acids with 5 to 7 carbon atoms. Use according to claim 3, wherein the sugar acid is gluconic acid or is glucoheptonic acid. Use according to one of claims 1 to 4, wherein at least one of the amides in an oily or aqueous composition is included. Use according to claim 5, wherein the composition additionally contains at least one anti-corrosion agent. Use according to claim 6, wherein the anti-corrosion agent is a boric acid ester. Use according to one of claims 5 to 7, wherein the Composition still contains at least one emulsifier. Use according to one of claims 5 to 8, wherein the Composition at least one polyalkylene glycol contains. Use according to one of claims 5 to 9, wherein the at least one amide up to 70% by weight of the composition matters. Use according to claim 10, wherein the composition diluted with water is applied, so that at least an amide makes up 0.01 to 3.0% by weight of the composition. High pressure additive (EP additive), especially for lubricants, Metalworking fluids and hydraulic fluids, containing at least one amide Polyhydroxycarboxylic acid. Additive according to claim 12, characterized in that there is also at least one anti-corrosion agent and / or contains at least one emulsifier. Additive according to claim 12 or 13, characterized in that that there is additionally at least one polyalkylene glycol contains. Additive according to one of claims 12 to 14, characterized in that that the at least one amide 0.01 to 70 wt .-% of the composition. Additive according to claim 15, characterized in that it contains at least one of the following compounds as amide: N, N-dimethyl-gluconamide, N- [2- (hydroxyethyl)] gluconamide, N- [2- (aminoethyl)] gluconamide, N- [2- (hydroxypropyl)] gluconamide, N- [1,2-dihydroxypropyl] gluconamide, N, N-dimethyl-glucoheptonamide, N- [2- (hydroxyethyl)] glucoheptonamide, N- [2 (aminoethyl)] glucoheptonamide, N- [2 (hydroxypropyl)] glucoheptonamide, N- [1,2-dihydroxypropyl] glucoheptonamide.