Method for separating a cooling lubricant agent from a bearing lubricant

Translation of description of equivalent WO 2013107768 A2

Method for Starting race of coolant from

bearing lubricant

The invention relates to a separation process for working up used in devices for metal forming

Bearing lubricant. Furthermore, the invention relates to a bearing lubricant for in bearings at plants

is metal forming applications.

In installations for metal forming, for example, in aluminum cold rolling mills, are used as coolant for the

Molding process generally water-immiscible

Coolants in the form of low aromatic

Hydrocarbon mixtures used. Depending on the application, the coolants suitable lubricating additives, such as fatty alcohols, fatty acids or fatty acid esters, are added.

In aluminum cold rolling mills in addition to cooling lubricants and other lubricants, for example,

Bearing lubricants in closed circuits and on

Consumption lubrication points in use. As bearing lubricant typically high-boiling and high-viscosity oils are used on mineral oils.

Leakage from these lubricant circuits in the

Coolant can in the current state of

Technology can not be completely prevented. Such

Leaks, especially when using high-boiling and high-viscosity lubricant bearings critical to the rolling process, since various properties of the coolant,

For example, its viscosity and purity are affected. Especially critical are the aforementioned leaks for further manufacturing processes of metal forming, which include a thermal treatment of the rolled strip to set the metallurgical properties and / or the evaporation of the oil circulation. The high boiling and the chemical composition of the bearing lubricant requires namely that the bearing lubricant at high temperatures, such as occur for example in the thermal degreasing, incomplete evaporates. This results in unwanted deposits form on the rolled strip. The formation of such

Deposits is associated due to the order

Color change of the roll band called the blotch.

To prevent loss of quality, it is common to reduce the level of bearing lubricant contamination in the cooling lubricant through the regular exchange of coolant filling. This procedure is disadvantageous because with their cost of purchasing new, working

Disposal of contaminated cooling lubricant arise. Furthermore, the thermal treatment of the rolled strip which optionally consuming to be determined content must be at

Bearing lubricant impurities are adjusted in the cooling lubricant. This results in particular thermal degreasing of aluminum rolled products time, energy and investment-intensive processes.

In oil flood camps for roll neck to aluminum cold rolling mills, typically high-boiling mineral oils as

Bearing lubricant used. As already discussed, can with the current sealing technology leaks of Bearing lubricant can not be prevented in the cooling lubricant. Leakage of bearing lubricant from oil film bearings for roll neck in the coolant are particularly

process critical because such bearing lubricant

usually much more viscous as coolants and beyond have a significantly higher boiling. Thus, most significantly affected by leakage of such bearing lubricating viscosity and boiling of cooling lubricants.

The extent of contamination of the coolant by bearing lubricant depends, inter alia, on the leakage rate from the bearing lubrication systems. At a high leakage rate the shares of bearing lubricant can make impurities in the coolant the majority of the process critical Coolant.

To make matters worse, it current with the

Sealing technology is not currently possible leaks of

Cooling lubricant in the bearing lubrication system - ie the

reverse process - excluded. Such leaks contribute to the deterioration of the situation mentioned above. By the penetration of the coolant into the

Bearing lubrication system may lead to a drop in viscosity of the bearing Schier agent of the lubricity

Bearing lubricant greatly reduces and thus can lead to bearing damage. To prevent a cooling lubricant contamination in the bearing lubrication system to a

Viscosity drop results, the bearing lubricant, particularly highly viscous and high boiling mineral oils are added namely. Such a modified bearing lubricant is then - with a leak in the cooling lubricant - yet critical for the production process than the unmodified bearing lubricant.

Usually grows with increasing service life of the filling of the bearing lubrication system, the deterioration of

Manufacturing process at a leakage from the storage circuit in the cooling lubricant circuit.

It is known to work up coolant to

Impurities such as bearing lubricant from the

remove cooling lubricant. So describes the

Offenlegungsschrift 1,594,535 a process for purifying used oil mill, which as impurities contains water, solids and tramp oils. In this method, the impurities are removed by centrifugation and discontinuation from the rolling mill oil.

The present invention is based on the object of overcoming the disadvantages of the known separation processes.

In particular, a method is provided, with mixtures of bearing lubricants and coolants can be effectively separated with little effort and it is the particular task of the separation process, leakage of coolant into the bearing lubricant from the

Bearing lubricant to remove and this regeneration of the bearing lubricant, the viscosity and thus the

Lubricity of the bearing lubricant maintain.

Furthermore, the invention addresses the problem of providing a bearing lubricant, in particular for use in oil flood camps in devices provide for metal forming, which is sufficiently compatible with coolant and in

Advantageously, in the inventive process can be used and, moreover, against the bearing lubricants commonly used has the advantage that leakage of bearing lubricant in the coolant in a simple manner, preferably by a cooling lubricant filtration from the coolant

be removed. Finally, the invention addresses the problem of providing a bearing lubricant, in particular for use in oil flood camps in devices for metal forming

indicate which is particularly compatible with coolant, which can be used advantageously in the process of the invention, which is in case of leakage in the coolant in a simple manner, preferably by a cooling lubricant filtration from the coolant

can be removed, and that the case of leakage in

Metalworking fluid forms on the rolled strip at a thermal degreasing of manufactured with the coolant lalzbandes no undesirable deposits.

According to a first teaching of the present invention, the object is achieved by a process for working up in

einsetzbarem devices for metal forming

achieved bearing lubricant in the cooling lubricant, which is used in devices for metal forming, is separated from the bearing lubricant.

It was recognized that the removal of coolant from confusions of bearing lubricant and coolant is a particularly process-compatible separation processes. The inventive method is particularly suitable for removing rolling oil leaks from oil flood camps Rolling pin to aluminum cold rolling mills or their

Bearing lubrication systems.

The separation of the coolant from the

Oil spill bearing lubricant can in various ways known to the expert, for example by separators,

be accomplished. The separation by means of separators is possible if coolant and lubricant storage are immiscible or the cooling lubricant or only very limited solves the bearing lubricant, or unless promotional by adding the separation adsorbents or solvents multiphase systems

can be set. This results in significant

Limitations in the selection and in the use of the employed at a plant for metal forming

Coolants and lubricants warehouse.

Practical tests have shown that with separation processes that exploit the differing thermal properties of bearing lubricant and coolant, particularly good results can be achieved. So can be elaborate with thermal separation processes

Process steps such as the addition of the

Separation promotional adsorbents or solvents

avoid. An advantage of a thermal separation is the fact that they both good as well as poor miscibility of coolant and

can be carried out bearing lubricant. In addition, a thermal separation is characterized by a high

Discriminatory power. Also advantageous is at a thermal isolation that more light impurities the bearing lubricant, such as water, are automatically mitabgetrennt.

The inventive method is suitable in principle for the separation of all coolants commonly used from the bearing lubricants commonly employed.

Particularly high separation effects are obtained in the separation of water-immiscible cooling lubricants according to DIN 51385, especially coolants, hydrocarbons, preferably in a proportion of at least 50 wt.%, Preferably of at least 70 wt.% And in particular of at least 90 wt.% By weight. It is advantageous if the boiling of the coolant in the range of 180 to 320 ° C. Excellent furthermore suitable coolants that at 40 ° C has a kinematic viscosity according to DIN 51562-T1 of more than 10 mm²/ S, preferably 1 to 5 mm²/ S, yet

more preferably from 1.5 to 3.5 mm²/ S and especially of at most 3 mm²/ S have. Preferably, the separation of the coolant from the bearing lubricant is a distillation process

performed. Distillation methods used are known to the different high boiling ranges of participating

Substances. At a certain temperature is the

Vapor pressure of the substance with the lower boiling, for example, of the coolant is higher than the

Vapor pressure of the substance with the higher boiling,

For example, the bearing lubricant. The substance having the lower boiling thus accumulates in the gas phase or is depleted from the liquid phase. is through a specifically conducted condensation of the gas phase - preferably spatially separated from the original liquid - a liquid obtained corresponds to the composition of the gas phase. In a continuous distillation process as the different substances can be effectively separated.

To obtain a high degree of separation, it is advantageous to employ a bearing lubricant, having a flashpoint of at least 50 ° C, preferably at least 70 ° C and in particular

at least 90 ° C, higher than the flash point of the coolant used is.

In a further advantageous embodiment of the

Process of the invention the distillative separation of the coolant at reduced pressure (vacuum), in particular at a pressure of less than 1 atm, and / or at an elevated temperature, in particular at a

Temperature of more than 25 ° C is performed. Good results are usually obtained when setting the

Distillation temperature to between 25 ° C and 180 ° C, preferably between 50 ° C and 160 ° C. Excellent to distillation temperatures are not exceeding 150 ° C,

preferably from 50 ° C to 130 ° C and especially from 70 ° C to 110 ° C. As is known in the art, the boiling ranges of the substances to be separated can be reduced according to its vapor pressure curve by reducing the pressure. Preferably, the distillative separation of the coolant at a pressure of less than 5 mbar, preferably from 0.1 mbar to 3 mbar, particularly 0.5 mbar to 2 mbar

performed. The use of low distillation temperatures is advantageous because the space required for the distillative separation of thermal energy consumption is reduced.

In addition, the products to be separated are spared. Thus, at low temperatures by the action of heat initiated undesirable oxidative and / or thermal

Processes, the chemical composition and the

physical properties, particularly the

impair lubricity of the bearing lubricant, such as oil oxidation, oil sludge formation (polymerization) or decomposition, reduced or even avoided altogether. The gentle nature of the separation by distillation may further by short residence times of the lubricant

favoring separation apparatus.

It is possible for the distillative separation of the

Cooling lubricant from the bearing lubricant in the form of a

perform batch distillation. Preferably, the separation by distillation of the

Cooling lubricant a falling film evaporator used.

Falling-film evaporators preferably consist of a stationary bundle of long tubes in which the product to be distilled

Liquid is fed at the top and flows down as a film. In shell space heating is provided for example by steam. In the tubes vapor bubbles that flow with the liquid down and ensure turbulent conditions form. Vapor and liquid separate the lower end usually in a separation vessel.

In a further particularly advantageous embodiment of the method for the distillative separation of the Coolant technology, a method based on

Film distillation or flash distillation

performed. In these methods, the evaporation is carried out of

Cooling lubricant in the interior of a preferably cylindrical tube made of a thin film. This film has the

Bearing lubricant as a main component, and is continuously mixed with a wiper system. The heating of the

Evaporator wall is expediently carried out externally via a jacket.

The above-mentioned method, for example, with respect to the bubble distillation, among other things, the advantage that it low at very low pressure and thus also in

Temperatures may be performed. Moreover, the products can very quickly from the separation apparatus

be removed and thus supplied for further use quickly. For this reason, these methods are particularly gentle on the products to be separated. Furthermore, the method of the thin film and short path distillations are also ideal for highly viscous media and thus especially for the employed at facilities for metal forming

Bearing lubricant, usually at 40 ° C a

kinematic viscosity according to DIN 51526-T1 of about 30mm²/ S have.

The separation process according to the invention can be carried out in the bypass or the full flow of the bearing lubrication circuit. The advantage of a purification in the bypass, that the circulation of the bearing lubricant no

undergoes degradation and thus the operation of the facilities can be maintained continuously for metal forming. Thus, in the purification in the bypass

constant process conditions are adhered to. Furthermore, the expenditure on equipment due to the

relatively low throughput of bearing lubricant low. A further advantage is that

Impurities in the bearing lubricant circulation may be removed promptly. Purification in the secondary flow is particularly useful when a rather low level is expected on pollution.

When associated with an increased degree is expected to contamination, it is technically advantageous to employ a purification in full flow.

It is likewise possible to carry out the inventive method in the form of a modal purification. With a batch-wise purification, a defined amount of

Bearing lubricant in a very thorough process, are cleaned. In addition, it is possible to

Purification of space systems, on which the

Bearing lubricant is used, be done separately. This allows greater flexibility for the structural

Design of equipment for metal forming.

A major advantage of the method is that already with the usually as

Bearing lubricant applied products, such as mineral oils or mineral oil-based products a good

Separation performance can be achieved. Thus, with the inventive method, the continuity with the lubricants used hitherto in the prior art and the associated empirical values ​​are maintained.

To a leakage of bearing lubricant in the

Coolant to prevent the formation of several phases, it is favorable to use a bearing lubricant in at least 5%, preferably at least 10% the

is soluble coolant. It is likewise favorable to use a coolant which is soluble to at least 5% in the bearing lubricant to namely a case of leakage of coolant into the bearing lubricant

Forming a plurality of phases and the associated

To avoid impairing the lubricity of the bearing lubricant.

A good separation efficiency is also with synthetic

Lubricants scored as bearing lubricant. As for the novel process particularly suitable synthetic bearing lubricant to products which have proven

Polyisobutylene and / or polyalphaolefin included. These products can also be used together with mineral and / or other commonly used lubricants in bearing components. Advantageously, the use of polyisobutylene as

Bearing lubricant is in particular that these compounds can be decomposed without residue-free by a thermal treatment. This is in case of leaks of

Bearing lubricants in the metalworking fluid at a particular optionally provided thermal treatment of the rolled strip is advantageous. Moreover, bearing lubricant record polyisobutylene base by a good miscibility with

Mineral oils from. This makes the use of spectrum of bearing lubricant is increased. show addition

Bearing lubricant on polyisobutylene base an also good miscibility with the products normally used as a coolant. This is particularly

advantageous because the risk can be eliminated that two phases are formed in the bearing lubrication system in the leakage of coolant. Further, even a conditional by the phase separation of cracking

Lubricating film can be prevented securely.

However, the use of bearing lubricants has to

following polyisobutylene based on aluminum cold rolling mill

disadvantages:

- At too high polyisobutylene impurities of

Cooling lubricant, for example, by a leakage in the bearing lubrication system and / or at too low temperatures during the thermal treatment of the rolled strip can lead to the formation of residues, whereby the

Surface quality of the rolled strip may be affected;

- Polyisobutylene residue on surfaces, the

Consistency of a sticky mass, as can the application of products on polyisobutylene basis in the field of

Aluminum cold rolling mills require an increased handling expenses; - Polyisobutylene-contamination in the cooling lubricant may not like the bearing lubricant usually used based on mineral oils on the

Coolant filtration are removed.

There is therefore a need for further

Bearing lubricants, especially bearing lubricants for oil flood storage in devices for Metallumformumg that as sufficient compatibility with the commonly

show products coolant used. In addition to possible contamination of

Bearing lubricant with coolant via the

be removed inventive well. Above all, contamination of the coolant itself should by bearing lubricant, for example, leakage of

Bearing lubricant in the cooling lubricant, can easily, preferably removed by a coolant filtration. This object is achieved according to a further teaching of the invention by providing a bearing lubricant exhibiting at least one carbon and oxygen

Synthetic oil having a kinematic viscosity of 60 to 220mm²/ S, preferably from 70 to 150mm²/ S, measured at 40 ° C according to DIN 51562-1, a ratio of oxygen to

Carbon of at least 1 to 12, preferably from

at least 1 to 10 and an average molecular weight from 1200 to 3500 g / mol and at least one

Oxidation inhibitor having a flashpoint at 1 atm of at least 150 ° C, preferably contains at least 170 ° C and in particular of at least 190 ° C. The bearing lubricant invention has sufficient compatibility with the commonly called

Coolant applied products, for example,

Kohlenwassestoffgemischten, on what is particular case of a leak of Lagerschmiermittel- and coolant circulation beneficial.

In addition, can be commonly referred to as

Coolant used products with the

separate methods of the invention in a simple way by this bearing lubricant.

The bearing lubricant of the invention is

particularly suited for thermal separation of cooling lubricant from the bearing lubricant. But above all, bearing lubricant to the invention can in a simple manner preferably by leakage of bearing lubricant in the case of contamination of the coolant through a cooling lubricant filtration from the coolant

remove. This possibility arises, provided for

used coolant filtration filter aid, where bearing lubricant to the invention are adsorbed. This is especially true for the use of filter aid mixtures including

Filter aids based on bleaching earths.

According to a preferred embodiment of the invention bearing lubricant to the invention contains a

Anti-corrosion agents.

As corrosion protection agents are conventional

Anti-corrosion agents. Preferably, the Anticorrosive agents an initial boiling point at 1 atm of at least 150 ° C, preferably at least 150 ° C. So are, for example nitrogen compounds,

preferably basic nitrogen compounds such as tertiary amines or their salts of benzoic, salicylic or

Naphthenic acids, esters of fatty, naphthenic or

Dicarboxylic acids with triethanolamine,

Erdalkaliphthalylalkylamide, amino-dicarboxylic acids,

Dicyclohexylamine and heterocyclic diamides hydroxyamines and imino esters, amides, and amide oximes Diaminomethanderivate.

Also suitable are fatty acid amides, particularly amides of saturated fatty acids with alkanolamines, alkylamines, sarcosine or imidazolines.

Also suitable are phosphoric acid derivatives, in particular diaryl phosphates and thiophosphates or neutral salts of primary n-alkylamines (C_8th-C₁₈) Or cycloalkylamines with dialkyl.

Also useful are sulfonic acids or other

Sulfur compounds. Also suitable are combinations of Ba-sulfonates and polyoxäthylierten alkylphenols,

Reaction products of dipentene with sulfur in the presence of activated alumina, combinations of base octylphenolsulfid, Ca and Na-petroleum sulfonate,

Alkylmercapto and -sulfinylessigsäuren, as well as mixtures of oil-soluble alkali or Erdalkalisulfonaten, fatty acids with ethylenediamine (sarcosines) or diethylenetriamine.

Also suitable are carboxylic acid derivatives, especially naphthenic acids, Calciumnaphthenate, zinc salts, hydroxy, and Ketocarboxylic acids, dicarboxylic acids, maleic acid, unsaturated fatty acids, hydroxy fatty acids and esters of all of these

Acids, pentaerythritol and sorbitan monooleate and 0- Stearoyl-alkylol, polyisobutenyl succinic derivatives, mixtures of dicarboxylic acid and their mono-2- hydroxyisopropylester, p-alkyl phenoxycarboxylic,

especially -acetic.

The amount of the anticorrosive agent used can vary. Amounts of less than 5 are particularly low weight.%, And especially weight amounts of 0.1 to 2.%.

Moreover, the bearing lubricant usual

Additives such as extreme pressure additives / extreme pressure additives,

Anti-wear additives, friction modifiers, adhesives, viscosity improvers Indes, detergents, demulsifiers, emulsifiers, nonferrous metal inhibitors and / or

Antifoaming agent, preferably in an amount of less than 5. Wt.%, And particularly in an amount of 0.1 to 2% by weight, contain. Particularly favorable is the use of additives which have a flash point at 1 atm of at least 150 ° C, preferably of at least 170 ° C and in particular of at least 190 ° C. In this way, the thermal releasability of the bearing lubricant and of the coolant is not adversely affected by the additives.

The bearing lubricant of the invention comprises at least one antioxidant. When antioxidants are the known antioxidants are if they have a

Flash point at 1 atm of at least 150 ° C, preferably from at least 170 ° C and in particular comprise at least 190 ° C.

So are, for example sulfur compounds,

especially alkyl sulfides, polysulfides, diaryl, modified mercaptans Mercaptobenzimidazoles, thiophene derivatives, xanthates, zinc dialkyl dithiocarbamates,

Thioglycols and aldehydes. Of the alkyl aromatic compounds S- dibenzyl be mentioned. Also suitable are alkyl phenol. is particularly suitable

4, 'thio-bis (2-tert-butyl) -5-methylphenol. Also suitable are 2-mercaptobenzimidazole, mercaptotriazines,

Reaction products of benzotriazol-alkyl vinyl ethers or - ester, 10H-phenothiazine and its alkyl derivatives, as well as 3,3'-thio-bis- (propionsäuredodecylester) and bis (3, 5-di-tert-butyl-4-hydroxybenzyl) malonic acid bis (3-thiapentadecyl) - ester. Also suitable are sulfoxides, preferably in combination with aromatic amines. Suitable phosphorus compounds are as preferably

Triaryl and trialkyl phosphites, phosphoric acid-phenol derivatives such as 3, 5-di-tert-butyl-hydroxybenzyl-phosphonic acid dialkyl esters or Phosphonsäuredipiperazide. Sulfur-phosphorus compounds are also suitable as

Metal salts of thiophosphoric acid compounds, especially zinc dialkyldithiophosphates. Also suitable are Zn and Ba dialkyldithiophosphates are also suitable

Reaction products of P₂S₅ with terpenes (Dipenten-, α-pinene), polybutenes, olefins and unsaturated esters, of which especially the terpene and polybutene-reaction products. Also suitable are phenol derivatives, particularly hindered monovalent and di- and trihydric phenols, hindered di- and trinuclear and polynuclear phenols. Particularly suitable are polyalkyl,

especially methylene 4, 4 '-bis- (2, 6-di-tert-butylphenol).

Excellent results were obtained 2, 6-di-tert-butyl-4-methylphenol. At higher temperatures or bis

Trisphenols, and esters of 3- (3, 5-di-tert-butyl-4 ~

hydroxyphenyl) -propionic acid and 2, 6-di-tert-butyl - (dimethylamino-methyl) phenol is preferred. Also suitable is the reaction product of Alkylthiohydrochinon and

Butylamine.

Also suitable are amines, in particular oil-soluble amines such as diphenylamine, phenyl-naphthylamine, ρ, ρ'-

Tetramethyldiaminodiphenylmethane. Particularly at higher temperatures, alkylated (C are_8th, C₉) Diphenylamine and N, N 'diphenyl-p-phenylenediamine. Practical tests have shown that with high-boiling phenolic antioxidants having a flashpoint of at least 150 ° C both in the protection of

Bearing lubricant from aging due to thermal stress in the camp and in the thermal separation of

Bearing lubricant and coolant is concerned, particularly good results are achieved by the coolant and in the efficiency of thermal separation of bearing lubricant and bearing lubricant additives. Moreover, practical experiments have shown that particularly good results are achieved, what the protection of the bearing lubricant from aging by thermal stress in the camp and in the thermal separation of

Bearing lubricant and coolant is concerned, if in addition to a phenolic oxidation inhibitor is a high boiling aminic oxidation inhibitor with a

Flash point is used of at least 150 ° C. in a concentration of 0.1 to 3, preferably. wt.%, in particular 0.5 to 1.5 wt%. Very particularly preferred is the use of an alkylated diphenylamine in a concentration of 0.5 to 1.5 wt.% Is.

The concentration of the oxidation inhibitor in the

Bearing lubricant is preferably 0.1 to 3 wt.%, Preferably 0.5 to 1.5%. According to a preferred embodiment of the invention, the bearing lubricant is a synthetic oil having a ratio of oxygen to carbon of 1 to 12-1 to 1, preferably from 1: 5 to 1: 2 and in particular from 1 to 4 to 1 to 2.5. Such a bearing lubricant shows a still sufficient compatibility with the conventionally used as a cooling lubricant products, such as mineral oils. In addition, cooling lubricants are particularly easy to separate from such a bearing lubricant. But above all, can be the kind

Bearing lubricant in the case of contamination of

remove cooling lubricant by bearing lubricant in a simple manner, preferably by a coolant filtration using filter aids. this applies

in particular for the use of Filterhilfsmittel- mixtures, which also contain filter aids based on bleaching earths. According to another preferred embodiment form of the

Invention, the bearing lubricant at 40 ° C a

kinematic viscosity from 60 to 220 mm²/ S, preferably from 70 to 150 mm²/ S on.

Practical tests have shown that with

Polyalkylene glycol, carboxylic acid esters, preferably diesters and / or polyol esters, in particular esters of a C₄-C₂O

Alcohol with a C6-C22 dicarboxylic acid and / or esters of a C₂-Cio Polyhdroxyalkohols with a C6 ~ C_3S Mono- and / or

Dicarboxylic acid, particularly good results are achieved.

Advantageously, the use of polyalkylene glycol, frequently for the symbol "polyglycol" is used in the literature, is that leakage of the coolant in the

Bearing lubricant are separated by the inventive method in a simple manner. It is particularly advantageous that in case of leakages of the bearing lubricant in the

Metalworking fluid, the viscosity of the coolant, and its compatibility is hardly affected by an optionally provided subsequent thermal treatment of the rolled strip, for example, an aluminum rolled strip. The reason is that caused by a leakage of bearing lubricant

Polyalkylenglykolverunreinigungen in the cooling lubricant in a particularly simple and effective manner, a

be removed from the coolant coolant filtration. is particularly suitable for this purpose the

Performing a full-flow filtration as

Precoat, preferably using Filter aids, preferably under partial or complete use of filtration auxiliaries based on bleaching earths. In addition,

Polyalkyleneglycol the advantage of being in the thermal

decomposing treatment of the rolled strip, ie

Polyalkyleneglycol deemed "glühfreundlich".

Another advantage of the use of polyalkylene glycol is polyalkylene glycol that has a particularly high as compared to mineral oils viscosity index. Thus, by the use of polyalkylene glycol has a high viscosity of the bearing lubricant can be adjusted, which is beneficial to the useful in a bearing lubrication system

Temperature interval affects.

In addition can be through the use of

Polyalkyleneglycol operational impairment of systems for metal forming, in particular the production of aluminum rolled products in aluminum cold rolling mills by the leakage of bearing lubricants, especially bearing oils from Ölfiutlagern for roll neck, decrease in the coolant. In particular polyalkylene increases

Process safety of rolling processes, since with him

leak-related increase in viscosity can be kept low or even completely avoided. Furthermore, can be explained by their use, the purity of the cooling lubricant improve, which corresponds to the requirements set by the customer. Finally, the cost of replacement or refurbishment of the coolant filling are lowered, and it is mainly in the production of aluminum foil the

Potential to shorten the subsequent heat treatment, for example by means of a Entfettungsglühens opened. Particularly good results are obtained with polyalkylene when used as a bearing lubricant in lubrication circuits at plants for metal forming, for example, in oil flood camps for roll neck in aluminum cold rolling mills. Particularly in this lubrication circuits can not completely leakage from the lubricating circuit in the cooling lubricant and leakage of coolant into the bearing lubricant in the current state of the art

be prevented.

Is a polyalkylene glycol lubricant containing stock is used, has the use of polyalkylene glycol having an average molecular weight of 1,200 to 3,500, more preferably from 1000 to 3000 g / mol, and in particular proven 1200-2500 g / mol as particularly favorable.

Excellent results are obtained with polyethylene glycol,

Polypropylene glycol, polybutylene glycol, in particular butanol-initiated polypropylene glycol, polytetramethylene glycol and / or block polymers and / or copolymers thereof achieved.

1 to 4: For the preparation of the polyalkylene glycol, in particular, the polymerization of ethylene and propylene oxide in a ratio of 0 is 1, preferably from 0: 1 to 2: 1, more preferably from 0: 1 to 1: 1 and in particular of 0:. 1

About the setting of the ethylene-to-propylene oxide (EO: PO) - ratio, the miscibility can be improved with the coolant and thus the risk of the formation of two

Phases are reduced. Furthermore, the election of the EO: PO ratio, the miscibility with the respective

Coolant used are adjusted.

Excellent results are also synthetic oils

obtained, having a content of ether groups, measured as the weight of the COC bound oxygen based on the molecular weight, from 20 to 40%, preferably from 20 to 30%.

Good results are also obtained with synthetic oils

Carboxylic acid esters, preferably diesters and / or polyol esters, in particular esters of a C₄-C₂o alcohol and a C6 ~ C₂2 dicarboxylic acid and / or esters of a C2-C10 Polyhdroxyalkohols with a C6-C36 mono- and / or dicarboxylic acid. Such synthetic oils include, unlike mineral oils, polyalphaolefins or polyisobutylenes about "polar", oxygen-containing molecule groups and thus on the

Potential in the event of a leak in the coolant through the coolant filtration to be removable. Moreover, the synthetic crude oils which contain polyester, also has the property to low residue decomposed with a thermal treatment.

In an advantageous embodiment of the bearing lubricant that is preferably more than 5% of synthetic carboxylic acid esters such as diesters, polyol esters or

Complex esters in which in turn the coolant to more than 5% is soluble. The bearing lubricant of the invention may in principle have a wide variety of flash points. By choosing the flash point of the bearing lubricant, an a thermal separation process favorable Abtrennverhalten set of possible cooling lubricant contamination. The boiling point of the bearing lubricant and

Boiling ranges optionally beige specified additives and other ingredients are preferably chosen so that they do not overlap temperature range with the boiling point of the

have cooling lubricant.

Preferably, a bearing lubricant with a

selected boiling point, which is as clear as possible on the final boiling point of the coolant and the optionally present coolant additives. It is also preferred that the bearing lubricant optionally added additives and other ingredients are with their boiling or its boiling point well above the final boiling point of the coolant and the coolant additives.

It is particularly advantageous if the flashpoint of the

Bearing lubricant at 1 atm at least 150 ° C, preferably at least 170 ° C and in particular at least 190 ° C. In this way, the thermal separation process may be particularly effectively conducted. The proportion of the synthetic oil in the bearing lubricant can vary within wide ranges. Practical tests have

showed that the proportion of the synthetic oil in the

Bearing lubricant advantageously at least 5 wt.%, Preferably at least 50 wt.%, More preferably at least 90 wt.% And in particular at least 95 wt.% To 99.5 wt.%, Is. It is also advantageous when the

Bearing lubricant at temperatures of 250 ° C to 350 ° C essentially no residue decomposes. The bearing lubricant of the invention is

excellent as an oil flood lubricant storage in devices for metal forming, especially in cold rolling mills.

It is particularly advantageous that the inventive process particularly simple manner coolant can be separated from the bearing lubricant and that bearing lubricant invention the particularly simple manner on the cooling lubricant filtration from

Coolant can be separated. With regard to further advantageous embodiments or advantageous effects of the present invention

Bearing lubricant is the to the explanations

directed separation process according to the invention. Test series of exemplary, not be regarded as limiting the use of bearing lubricant

Polyalkyleneglycol base in aluminum cold rolling mills with bearings with oil film bearing lubrication systems have shown that when using the inventive method, a

Contamination of the bearing lubricant could be limited by the cooling lubricant to less than 1%. Simultaneously, the bearing lubricant from the cooling lubricant were able to use the coolant filtration based on

Filter aids are limited to residual contents of less than 0.5%. So in exemplary laboratory tests it was possible to remove by the process of molecular distillation cooling lubricant from bearing lubricant on polyalkyleneglycol base to residual levels of less than 0.5%. In the short-path distillation at a pressure of 5 mbar at

Temperatures less than / equal to 120 ° C, in particular from 25 to 120 ° C, and at a pressure of 1 mbar at temperatures less than / equal to 100 ° C, in particular between 25 and 100 ° C, worked.