DE10007625A1 - Lubricant for metal forming - Google Patents

Abstract

The invention relates to the use of carbon dioxide esters of general formula (I) in lubricants for forming metals under the effects of sliding friction. In said formula: R and R' can be identical or different and each represent a linear or branched alkyl group, a cycloalkyl group or an alkyl-cycloalkyl group, each with between 5 and 30 C atoms. The invention also relates to lubricants containing carbon dioxide esters of general formula (I) and one or more components selected from a) mono and/or diesters of mono or oligophosphoric acids with between 1 and 6 P atoms having linear or branched fatty alcohols with between 12 and 22 C atoms, or their non-esterified starting products b) triglycerides of fatty acids with between 12 and 22 C atoms and c) methyl esters of fatty acids with between 12 and 22 C atoms. The lubricants are preferably devoid of mineral oil.

Description

The invention is in the field of cold forming of metals such as for example the drawing of pipes, wires and profiles, the Cold massive forming and cold forming of components, for example by deep drawing or cold extrusion. These processes is common that the forming process with a strong sliding friction between Tool and workpiece is connected, in particular at the beginning of Forming process to overcome the start or static friction. During the Forming process can lead to "rattling" or "stick-slip effect", whereby the type of friction in short intervals between sliding and static friction changes. The forming processes mentioned differ in this from Cold rolling of metal strips, where mainly a rolling friction between Metal substrate and rollers occurs. To the sliding and static friction between To reduce the tool and workpiece in the above-mentioned processes becomes a Lubricant used. The present invention relates to such Lubricant.

Conventional lubricants for the applications mentioned are based on Mineral oil or similar hydrocarbons such as Petroleum distillates. Such substances are one under normal conditions industrial or municipal wastewater treatment plant not biodegradable and accordingly difficult and expensive to dispose of.

From EP-A-393 749 is the use of selected carbonic acid esters, there as called organic carbonates, known for rolling processes. EP-A-89 709 describes lubricants containing such carbonic acid esters for  Lubrication processes in which there is no metal deformation. examples are Lubricants for internal combustion engines or for use in industrial lubrication, for example in the form of gear oils or Compressor oils.

Neither occurs in the lubrication processes according to EP-A-89 709 Metal deformation on and the goal is the sliding friction between metal parts to minimize as much as possible. The forming processes by rolling according to EP-A 398 749 take place by rolling friction, whereby a sliding friction between the Rolls and the metal substrate should also be kept as low as possible.

In contrast to this, the present invention relates to forming processes of Metals by cold forming, with a strong sliding friction between Tool and workpiece occurs. Because here much greater frictional forces occur than in the processes according to EP-A-89 709 and EP-A-393 749 can Do not assume that lubricants are suitable for these processes are also used in the cold forming of metals with sliding friction can be.

The aim of the present invention is to provide lubricants for the To provide cold forming, which is less complicated to dispose of are and which preferably have an improved lubricating effect than conventional hydrocarbon-based lubricants.

The invention is based on the surprising finding that the in EP-A-89 709 and EP-A-393 749 also described carbonic acid esters for purpose can be used. This is especially true when supplemented with components that replace hydrocarbons such as mineral oil or petroleum distillates.

The invention thus relates in a first aspect to the use of carbonic acid esters of the general formula (I)

where R and R 'can be the same or different and each have a linear or branched alkyl radical, a cycloalkyl radical or an alkyl-cycloalkyl radical each with 5 to 30 carbon atoms, in lubricants for forming metals under sliding friction.

Such carbonic acid esters can by transesterification of carbonic acid esters lower alcohols (for example alcohols with 1 to 3 carbon atoms) with the less volatile alcohols with 5 to 30 carbon atoms. Closer Information on the production of these carbonic acid esters can be given at the beginning cited documents are taken.

The alkyl groups R and R 'of the alcohol component of the carbonic acid esters can correspond to primary, secondary or tertiary alcohols. Preferably put the radicals R and R 'are linear or branched alkyl groups having 6 to 30, in particular with 10 to 20 carbon atoms.

For the purposes of the present invention, preference is given to the carbonic acid esters of general formula (I) used in lubricants that do not contain mineral oil contain. Lubricants are preferred for the specified use used in addition to carbonic acid esters of formula (I) one or more Components selected from: a) mono- and / or diesters of mono- or Oligophosphoric acids with 1 to 6 P atoms with linear or branched Fatty alcohols with 12 to 22 carbon atoms or their non-esterified Starting products, b) triglycerides of fatty acids with 12 to 22 carbon atoms and c) contain methyl esters of fatty acids with 12 to 22 carbon atoms.

Furthermore, the lubricants for the use mentioned can additionally have one or more components selected from: d) terpenes, e) pour point depressants and f) alkylamines of the general formulas (IIa) and (IIb)

R "-NH ₂ (IIa)

R "- [NH- (CH ₂ ) _n -] _m NH ₂ (IIb)

contain, where R "is a linear or branched, saturated or one or polyunsaturated alkyl group with 8 to 22 carbon atoms, n is an integer in the Range from 1 to 4 and m are an integer in the range from 1 to 4.

With a suitable choice of components, lubricants which contain carbonic acid esters of the general formula (I) can be used not only for forming metals with sliding friction, but generally for lubrication purposes. Accordingly, the invention relates in an expanded aspect to lubricants containing carbonic acid esters of the general formula (I)

where R and R 'can be the same or different and each represents a linear or branched alkyl radical, a cycloalkyl radical or an alkylcycloalkyl radical each having 5 to 30 carbon atoms,
as well as one or more components selected from a) mono- and / or diesters of mono- or oligophosphoric acids with 1 to 6 P atoms with linear or branched fatty alcohols with 12 to 22 C atoms or their non-esterified starting products, b) triglycerides of fatty acids with 12 to 22 carbon atoms and c) methyl esters of fatty acids with 12 to 22 carbon atoms.

Here, too, it is preferred that the new lubricant additionally has one or more components selected from d) terpenes, e) pour point depressants and f) alkylamines of the general formulas (IIa) and (IIb)

R "-NH ₂ (IIa)

R "- [NH- (CH ₂ ) _n -] _m NH ₂ (IIb)

contains, where R "is a linear or branched, saturated or one or more unsaturated alkyl group with 8 to 22 carbon atoms, n is an integer in the range from 1 to 4 and m are an integer in the range from 1 to 4.

For the purposes of the present invention, these agents are also preferably free of Mineral oil.

The lubricant according to the invention is particularly characterized in that it contains 8 to 15% by weight of carbonic acid ester of the general formula (I) and one or more of the following components, based on the total lubricant:

• a) 8 to 42 wt .-% mono- and / or diesters of mono- or oligophosphoric acids with 1 to 6 P atoms with linear or branched fatty alcohols with 12 to 22 C- Atoms or their non-esterified starting materials,
• b) 20 to 38% by weight of triglycerides of fatty acids with 12 to 22 C atoms,
• c) 3 to 8 wt .-% methyl esters of fatty acids with 12 to 22 C atoms and

It is preferred that the lubricant additionally contains one or more of the following components:

• a) 5 to 25% by weight of terpenes,
• b) 0.1 to 0.5% by weight of pour point depressants,
• c) 3 to 8% by weight of alkylamines of the general formulas (IIa) and (IIb),

a remaining remainder consisting of 100% by weight of further auxiliaries and / or active ingredients.
where the proportions are to be selected so that their total amounts to a maximum of 100% by weight and a remaining 100% by weight of other active and / or auxiliary substances.

Component a) can in particular do the task of the so-called High pressure additives (Anglo-Saxon "extreme pressure additive", EP additive for short)  take. In conventional lubricants, this function is common organochlorine or sulfur compounds or also heavy metal containing Compounds such as compounds of tin, molybdenum or tungsten used. Due to the use of component a), such There are no additives that make it difficult to dispose of used lubricants become. Accordingly, there is a preferred embodiment of the invention Lubricant in that it is free from heavy metals and from chlorine and Sulfur compounds.

Components a) to f) are described in more detail below.

Component a) are mono- and / or diesters of mono- or oligophosphorus acids with 1 to 6 P atoms with linear or branched fatty alcohols with 12 up to 22 carbon atoms or their non-esterified starting products. In practice you bring this component into the lubricant by using mono- or Oligophosphoric acids with 1 to 6 P atoms or their anhydrides with the Mixed fatty alcohols. This occurs in part during the manufacture of the Lubricants, but sometimes only under the elevated temperatures of the Use an at least partial ester formation between the phosphoric acids or their anhydrides and the fatty alcohols. So it is not required the esters in a separate step before making the to synthesize lubricant according to the invention. Due to the Thermodynamics and the kinetics of ester formation are expected to result in that Lubricant a mixture of mono- and diesters as well as possibly not esterified Contains phosphoric acids or alcohols. As an oligophosphoric acid for example, tetraphosphoric acid with 4 P atoms can be used. Likewise their anhydride suitable. The alcohol component can be, for example represent technical fatty alcohol mixture, which by splitting and reduction of natural oils and fats is available. Such implementation products Natural fats and oils usually contain a mixture of fatty alcohols with different C chain lengths. For example, components with 14 to 20 carbon atoms are present, the majority of 16 to 18 carbon atoms having. For example, in the ready-to-use lubricant  Component a) from about 60 to 80% monoester, 10 to 20% diester and 10 to There is 20% free phosphoric acid. Is used instead of phosphoric acid their anhydride, the content decreases in the ready-to-use lubricant of free phosphoric acid in favor of the phosphoric acid ester. So can products are obtained in which component a) is composed, for example, of about 60 to 70 % Diesters and about 30 to 40% monoesters and almost no free acid consists.

Component b) is one of the components that makes it possible to get mineral oil dispense. This can be natural oils or fats or conversion products of this are provided that they are at the application temperature either liquid or dissolve in the remaining liquid components. At Substances that are liquid at room temperature are preferred as component b). This means that the fatty acid components of the triglycerides are preferably at least partially are unsaturated. For example, triglycerides are suitable, which have a high proportion have oleic acid. As with natural oils and fats and their As a consequence of secondary products, the triglycerides are present as mixtures of molecules, that contain different fatty acid components.

Component c) are methyl esters of fatty acids with 12 to 22 carbon atoms. These can be obtained by transesterifying natural fats and oils with methanol. Accordingly, there are usually products that contain mixtures of Represent methyl esters with fatty acids of different chain lengths. Such Fatty acid methyl esters are also known as "biodiesel" because they are an alternative to diesel are suitable as fuel for internal combustion engines. Together with or instead of component b), the methyl esters serve as a replacement for mineral oil in the Lubricants according to the invention.

Component d) can be a mixture of terpenes, possibly mixed with other natural products. Such terpene mixtures can be obtained industrially by distilling plant seeds. These distillation products from plant seeds generally contain a very complex mixture of individual molecules, with linear unsaturated hydrocarbons, alcohols and aldehydes also occurring in addition to the terpenes. Terpenic distillates of this type are commercially available as components of lubricants, for example the Globeoil ^R products from DE.FI.LU (Italy). These terpenes can also be regarded as substitutes for mineral oil in the formulations according to the invention.

Component e) are pour point depressants that the invention Lubricants can be added if its pour point should be lowered. It depends on the choice of the other components, whether such pour point depressants are required. Suitable products are on known in the field of lubricating oil preparation. For example Ethylenediaminetetraacetate tetraamide or derivatives thereof can be used.

The alkylamines of component f) can in turn be used as a substitute for mineral oil be considered. Such monoamines or oligoamines are, for example, as Components of belt lubricants known in the beverage industry. Oligoamines of the general formula (IIb) can be used as component f) become. For economic reasons, however, monoamines become the general Formula (IIa) preferred. These alkylamines are usually derived from Fatty alcohols by splitting and reacting natural fats and oils are available. Accordingly, these amines are often in the form of Molecular mixtures with different radicals R ". The radicals R "can be saturated or mono- or polyunsaturated. Amines are particularly preferred suitable in which the radical R "contains 12 to 20 C atoms. An example of this is the oleyl radical.

The products according to the invention can be free of mineral oils and also free made of heavy metals and chlorine and sulfur compounds become. The lubricating components are at least largely based on renewable raw materials such as vegetable or animal oils and Fat. Their disposal is simplified because the ingredients are in industrial or municipal sewage treatment plants are degradable. Besides these ecological advantages However, the lubricants according to the invention also have technical advantages:  

Compared to common oil-based products, their viscosity is up to 25% reduced, which makes the application easier. The pulling speed can Compared to mineral oil-based products can be increased, even one reduced surface roughness is achieved than with mineral oil products. At the Tubing can be reduced by 40 to 50% in one drawing step.

Claims (10)

1. Use of carbonic acid esters of the general formula (I)
where R and R 'may be the same or different and each is a linear or branched alkyl radical, a cycloalkyl radical or an alkyl-cycloalkyl radical
with 5 to 30 carbon atoms each, in lubricants for forming metals with sliding friction. 2. Use according to claim 1, characterized in that the lubricant contains no mineral oil. 3. Use according to one or both of claims 1 and 2, characterized characterized in that the lubricants other than carbonic acid esters of the formula (I) one or more components selected from: a) mono- and / or diesters of mono- or oligophosphoric acids with 1 to 6 P atoms with linear or branched fatty alcohols with 12 to 22 carbon atoms or their non-esterified Starting products, b) triglycerides of fatty acids with 12 to 22 carbon atoms and c) contain methyl esters of fatty acids with 12 to 22 carbon atoms. 4. Use according to claim 4, characterized in that the lubricants additionally one or more components selected from: d) terpenes, e) pour point depressants and f) alkylamines of the general formulas (IIa) and (IIb)
R "-NH ₂ (IIa)
R "- [NH- (CH ₂ ) _n -] _m NH ₂ (IIb)
contain, where R "is a linear or branched, saturated or mono- or polyunsaturated alkyl group having 8 to 22 carbon atoms, n is an integer in the range from 1 to 4 and m is an integer in the range from 1 to 4. 5. Lubricant containing carbonic acid esters of the general formula (I)
where R and R 'can be the same or different and each represents a linear or branched alkyl radical, a cycloalkyl radical or an alkylcycloalkyl radical each having 5 to 30 carbon atoms,
and one or more components selected from a) mono- and / or diesters of mono- or oligophosphoric acids with 1 to 6 P atoms with linear or branched fatty alcohols with 12 to 22 C atoms or their non-esterified starting products, b) triglycerides of fatty acids with 12 to 22 carbon atoms and c) methyl esters of fatty acids with 12 to 22 carbon atoms. 6. Lubricant according to claim 5, characterized in that it additionally contains one or more components selected from d) terpenes, e) pour point depressants and f) alkylamines of the general formulas (IIa) and (IIb)
R "-NH ₂ (IIa)
R "- [NH- (CH ₂ ) _n -] _m NH ₂ (IIb)
contains, where R "is a linear or branched, saturated or mono- or polyunsaturated alkyl group having 8 to 22 carbon atoms, n is an integer in the range from 1 to 4 and m is an integer in the range from 1 to 4. 7. Lubricant according to one or both of claims 5 and 6, characterized characterized that it is free from mineral oil. 8. Lubricant according to one or more of claims 6 to 8, characterized in that it contains 8 to 15% by weight of carbonic acid ester of the general formula (I) and one or more of the following components, based on the total lubricant:

• a) 8 to 42% by weight of mono- and / or diesters of mono- or oligophosphoric acids with 1 to 6 P atoms with linear or branched fatty alcohols with 12 to 22 C atoms or their non-esterified starting products,
• b) 20 to 38% by weight of triglycerides of fatty acids with 12 to 22 C atoms,
• c) 3 to 8 wt .-% methyl ester of fatty acids with 12 to 22 carbon atoms.

9. Lubricant according to claim 8, characterized in that it additionally contains one or more of the following components:

• a) 5 to 25% by weight of terpenes,
• b) 0.1 to 0.5% by weight of pour point depressants,
• c) 3 to 8% by weight of alkylamines of the general formulas (IIa) and (IIb), a remainder of the remaining 100% by weight consisting of further auxiliaries and / or active ingredients, the proportions being chosen so that their Total amounts to a maximum of 100% by weight and a remaining 100% by weight of the remainder consists of further active ingredients and / or auxiliaries.

10. Lubricant according to one or more of claims 5 to 9, characterized characterized in that it is free of heavy metals and chlorine and Sulfur compounds.