WO2006131363A1 - Polymer dithiophosphoric hydroxy fatty esters, method for producing the same and use thereof as lubricant additives - Google Patents

Abstract

The invention relates to polymer dithiophosphoric hydroxy fatty esters. They are produced by a method in which an epoxidized fatty acid ester is reacted with a substituted dithiophosphoric acid in such a manner that not all epoxide groups of the fatty acid ester are affected. The reaction is followed by an intramolecular cross-linking while forming hydroxyl groups. According to an alternative method, the epoxidized fatty acid ester is cross-linked to give a polymer intermediate which has non-reacted epoxide groups, and the free epoxide groups then react with the substituted dithiophosphoric acid while forming hydroxyl groups. The inventive polymer dithiophosphoric hydroxy fatty esters are generally suitable for use as lubricant additives, especially for improving the antiwear effect and aging stability of lubricants.

Description

 Polymeric dithiophosphoric acid hydroxy fatty acid esters,

Process for their preparation and their

Use as lubricant additive

The present invention relates to novel polymers based on Dithiophosphorsäurehydroxyfettsäureestern, processes for their preparation and their use as a lubricant additive.

Metalldialkyldithiophosphate are long known and until today much used lubricant additives. They are used mainly for their multifunctional properties to improve the wear protection and aging stability of mineral oils, for the production of motor oils, metalworking fluids, industrial oils and lubricating greases. Particularly effective here are the zinc salts of dialkyldithiophosphoric acids (zinc dialkyldithiophosphate) proved. However, these zinc compounds do not meet all requirements due to their metal or zinc content. The metals cause disturbing deposits on the lubricated friction elements due to the formation of ash.

Another disadvantage of these zinc dialkyldithiophosphates is their inconsistency with acids and water to form decomposition products which adversely affect the shelf life of the base oil by odor, sludge formation and oil clouding.

Metal-free dithiophosphoric acid derivatives are also known in the art.

In DE 42 42 502 Al metal-free lubricant additives based on addition products of glycidyl ethers and dialkyl dithiophosphoric acids of different alkyl, aryl or mixed alkyl-aryl group structure are described.

In DE 42 06 047 Al also metal-free lubricant additives are described, which are attributed to corrosion-inhibiting properties. These are reaction products of epoxidized unsaturated fatty acid esters with lower or higher molecular weight sulfonic acids.

In DE 42 31 073 Al further lubricant additives are described, which are formed by reaction of epoxidized fatty acids and fatty acid derivatives and phosphoric acid or their mono- or diesters. Disadvantages of these known metal-free lubricant additives are the still weak acid and hydrolysis resistance and the low wear protection effect under load.

The object of the present invention is therefore to provide metal-free lubricant additives which do not have the abovementioned disadvantages.

This object is achieved according to the invention by polymeric dithiophosphoric acid hydroxy fatty acid esters according to claim 21. These polymers are obtainable by a process according to claim 1 or claim 4.

The invention also relates to a specific polymeric dithio-phosphoric acid hydroxy fatty acid ester according to claim 22.

Furthermore, the invention relates to specific uses of the polymeric Dithiophosphorsäurehydroxyfettsäu- ester according to any one of claims 29 to 31.

Furthermore, the invention relates to a lubricant according to claim 33, which contains the polymeric Dithiophosphorsäurehydroxyfettsäureester invention.

Preferred embodiments will be apparent from the dependent claims.

The polymeric Dithiophosphorsäurehydroxy fatty acid esters according to the invention have not been previously known in the art. By the term "polymers" are meant here also oligomers, which can have only a small number of repeating units. In particular, such are also Compounds according to the invention in which the number of repeating units is at least 2 and preferably at least 3.

Surprisingly, it has been found that the polymers according to the invention have excellent lubricating properties. They also have a good wear protection effect under load, which is not achieved with the known metal-free lubricant additives. In addition, they improve the aging properties of a base oil and have good acid and hydrolysis resistance. Thus, they meet the property profile that is placed on a modern lubricant additive, without the disturbing deposits caused by ash formation occur on the lubricated friction surfaces as in the metal-containing lubricant additives.

The polymeric Dithiophosphorsäurehydroxyfettsäureester invention are obtainable by two production routes, both of which take place in two steps. In the first method, epoxidized fatty acid esters are first reacted with substituted dithiophosphoric acids, not all of the epoxide groups of the fatty acid ester being attacked. In a further reaction step, the polymerization is carried out with a multifunctional H-acidic compound via an intermolecular crosslinking and formation of hydroxyl groups. In the second method, epoxidized fatty acid esters are reacted with a multifunctional H-acidic compound such that the epoxidized fatty acid esters are intermolecularly crosslinked to form a polymeric intermediate having free epoxide groups. The free epoxide groups are then reacted with the substituted dithiophosphoric acid to form hydroxyl groups. implemented (inverse method). Both production routes are described in detail below.

In step (a) of the first process according to the invention, an epoxidized fatty acid ester of the formula (I)

(D with A = RiO or H,

wherein x is a number from 0 to 6 and R ₁ , R ₂ and R _{3 may be the} same or different and are as defined below:

R ₄ - (CH ₂ ) _p - [(CH-CH) _n (CH ₂ ) J-Cff

wherein R _{4 is} H or -CH ₃ , m is a number from 1 to 40, n is a number from 1 to 10 and p is a number from 0 to 8,

with a substituted dithiophosphoric acid of the formula (II)

R ₆ -O 'SH

(II)

implemented wherein R ₅ and R _{6 may be the} same or different and are independently selected from H, alkyl or aryl, provided that at least one of R ₅ and R _{6 is} not H,

wherein the fatty acid ester of formula (I) is reacted with the dithiophosphoric acid of formula (II) to form an intermediate with unreacted epoxide groups.

In the epoxidized fatty acid ester of formula (I), x is a number from 0 to 6, preferably 1 to 4, more preferably 1 or 2 and most preferably 1. Thus, the fatty acid ester of formula (I) is in the case of x = 1 and A = RiO derived from glycerol and in the case of x = 1 and A = H derived from propylene glycol.

In the radicals R 1, R ₂ and R _{3 of} the fatty acid ester of the formula (I), R _{4 is} H or -CH ₃ . m is a number from 1 to 40, preferably 7 to 29 and particularly preferably 10 to 16. n is a number from 1 to 10, preferably 2 to 4 and particularly preferably 2 or 3. p is a number from 0 to 8, preferably 2 to 5 and more preferably 3 or 4.

In this case, the individual methyl units (CH ₂ ) provided with the index m and the individual epoxide units (CHOCH) provided with the index n can be distributed in any order over the chain, ie in random, blockwise or alternating arrangement. However, it is preferred that at least 2 methylene units (CH ₂ ), particularly preferably 7 methylene units (CH ₂ ), follow the carbonyl group before one or more of the epoxide units (CHOCH) and again methylene (CH ₂ ) follows. In a preferred embodiment, the epoxidized fatty acid esters of formula (I) are derived from epoxidized oils of natural origin. The epoxidized oil of natural origin may be selected from epoxidized soybean oil, linseed oil, rapeseed oil, sunflower oil and fish oil. This list is exemplary only and does not limit the range of epoxidized oils of natural origin.

It is equally possible to use synthetic epoxidized fatty acid esters, e.g. an epoxidized propylene glycol dioleate, epoxidized glycol dioleate, epoxidized butane dioleate or epoxidized glycol dilaurylate.

Preferably, the percentage content of oxirane oxygen in the fatty acid ester of the formula (I) is greater than 2 wt .-% and particularly preferably greater than 3 wt .-%. The percent oxirane oxygen content in an epoxy compound (such as the fatty acid ester of formula (I)) indicates how many grams of oxirane oxygen are contained in 100 grams of epoxy compound and is determined by perchloric acid titration. This method, as described in A.J. Durbetaky, Anal. Chem. 28, 2000 (1956), R.R. Jay, Anal. Chem. 36, 661 (1964) or R. Deistra and E. Damen, Anal. Chem. Acta. 31, 38 (1964), is well known to those skilled in the art.

The substituted dithiophosphoric acid of formula (II) is preferably substituted on both O atoms, wherein R ₅ and R ₆ independently of one another are alkyl or aryl. Thus, the dialkyl, diaryl and the mixed alkyl / aryl dithiophosphoric acids are preferably used. Even more preferred is when R ₅ and R _{6 are} each alkyl. The alkyl radicals preferably have 4 to 12 carbon atoms and more preferably 6 to 8 carbon atoms, and may be unbranched or branched. As an example, the compounds Di-2 ethylhexyldithiophosphoric acid (R ₅ and R ₆ = 2-ethylhexyl), di-n-octyl-dithiophosphoric acid (R ₅ and R ₆ = n-octyl), di-iso-butyl-dithiophosphoric acid (R ₅ and R ₆ = isobutyl) , Iso-butyl, -2-ethylhexyldithiophosphoric acid (R ₅ = isobutyl and R ₆ = 2-ethylhexyl). It is very particularly preferred if R ₅ and R _{6 are} each C ₆ - to C ₈ -alkyl, such as, for example, in the abovementioned compounds di-2-ethylhexyldithiophosphoric acid and di-n-octyl-dithiophosphoric acid. Most preferred is di-2-ethylhexyl dithiophosphoric acid.

Preferably, such amounts of the fatty acid ester of the formula (I) and the dithiophosphoric acid of the formula (II) are used, that an intermediate product is formed with unreacted epoxide groups. It is further preferred that the ratio of the number of epoxide groups of the fatty acid ester to the thiol group of the dithiophosphoric acid is at least 1: 1, more preferably 3: 2 and most preferably 3: 1.

The reaction in step (a) is preferably carried out at a temperature of 20 to 40 ⁰ C without the presence of solvents. The reaction time is preferably 0.5 to 1.5 hours.

In step (b) of the first process, the intermediate having unreacted epoxide groups is reacted with a crosslinking compound to form the polymeric dithiophosphoric hydroxy-hydroxy acid ester wherein the crosslinker compound intermolecularly reacts with two or more epoxide groups.

Suitable crosslinker compounds are any molecule which has at least two functional, H-acidic groups and can react intermolecularly with the free epoxide groups. A preferred crosslinker compound has the formula (III) L- (XH) _Z

(III)

in which L is a molecular unit, -XH is a functional, H-acidic group, wherein X is independently oxygen or sulfur and z is at least 2. In this case, L can be an inorganic or organic molecular unit.

In a particularly preferred embodiment, the crosslinker compound of the formula (III) has two functional, H-acidic groups (z = 2). In this case, it is a bi-functional molecule that can react intermolecularly with two epoxide groups. In addition, it is then preferred that both X are each oxygen or sulfur. Preferred bifunctional crosslinker compounds are selected from naphthalenedisulfonic acids, aliphatic and / or aromatic saturated dicarboxylic acids, monoalkylphosphoric acid esters, mixtures of monoalkyl phosphoric acid esters and dialkylphosphoric acid esters and dimer captothiadiazoles. Most preferred are dinonylnaphalindisulfonic acid, 2-ethylhexylphosphoric monoester, mixtures of 2-ethylhexylphosphoric monoester and 2-ethylhexylphosphoric acid diester, and 2,5-dimercapto-1,3,4-thiadiazole.

The reaction in step (b) is preferably carried out at a temperature of 80 to 150 ⁰ C without the presence of solvents. The reaction time is preferably 0.5 to 1.5 hours.

The first preparation route just described is illustrated by FIG. 1, which shows by way of example the reaction of an epoxidized fatty acid glyceride with di-2-ethylhexyldithio-phosphoric acid and the subsequent polymerization with 2,5-dimercapto-1,3,4-thiadiazole. In the second process of the present invention, in step (a), an epoxidized fatty acid ester of the above formula (I) is reacted with a crosslinker compound, wherein the crosslinker compound intermolecularly reacts with two or more epoxide groups and the fatty acid ester and the crosslinker compound are reacted together to form a polymeric one Intermediate is formed with unreacted epoxide groups. The crosslinker compound used is the same compounds as have already been described in connection with the first preparation route.

Preferably, such amounts of the fatty acid ester of formula (I) and the crosslinker compound are employed to form a polymeric intermediate having unreacted epoxide groups. It is further preferred that the ratio of the number of epoxy groups of the fatty acid ester to functional, H-acidic groups of the crosslinker compound of the formula (III) is at least 1: 1, more preferably 10: 1 and most preferably 20: 1.

The reaction in step (a) is preferably carried out at a temperature of 30 to 100 ⁰ C without the presence of solvents. The reaction time is preferably 0.5 to 1.5 hours.

In step (b) of the second process, the polymeric intermediate having unreacted epoxide groups is then reacted with a dithiophosphoric acid of formula (II) above to form the polymeric dithiophosphoric hydroxyester fatty acid ester.

The reaction in step (b) is preferably carried out at a temperature of 30 to 100 ⁰ C without the presence of solvents. The reaction time is preferably 0.5 to 1.5. The second preparation route just described is illustrated by FIG. 2, which shows, by way of example, the reaction of an epoxidized fatty acid glyceride with 2,5-dimercapto-1,3,3,4-thiadiazole into a polymeric intermediate and the subsequent reaction with di-2-ethylhexyldithiophosphoric acid ,

As an optional measure may be in both procedures before or after

Step (b) adding a hydrolysis protection agent. A preferred hydrolysis inhibitor is an oil-soluble and sterically hindered arylcarbodiimide. By way of example, bis-

(2, 6-diisopropylphenyl) carbodiimide listed.

Optionally, it may be necessary to filter the reaction product to remove fine particles.

In a further embodiment, the polymeric dithiophosphoric acid hydroxy fatty acid ester according to the invention comprises the following regularly repeating unit:

R ₄ - (CH ₂ ) _p - [(E ₁ UCH ₂ ) JR ₄

wherein R _{4 is} independently H or -CH ₃ ,

E _{1 is} the formula

aufweist,

having,

E _{2 is} the formula

X

I L

I X H

in which L is a molecular unit and X is independently oxygen or sulfur,

E _{3 is} the formula

OH H

wherein R ₅ and Re may be the same or different and are independently selected from H, alkyl or aryl, provided that at least one of R ₅ and R _{s is} not H,

and wherein each m is a number from 1 to 40, n is a number from 1 to 10 and p is a number from 0 to 8. In this case, R ₅ , R ₆ , m, n, p, L and X are those preferred embodiments which have been described in connection with the inventive method. In each of the fatty acid-derived residues of the above triglyceride structure, the individual methylene moieties (CH ₂ ) provided with the index m and the individual units Ei, E ₂ or E ₃ provided with the index n may be distributed throughout the chain in any order ie in statistical, block or alternating order. However, it is preferred that at least 2 methylene units (CH ₂ ), more preferably 7 methylene units (CH ₂ ), follow the carbonyl group before one or more of the units E ₁ , E ₂ or E ₃ and again methylene (CH ₂ ) follows ,

However, particularly preferred polymeric Dithiophosphorsäurehydroxy fatty acid esters are those compounds in which independently R ₅ and R _{6 are} each C ₆ - to C ₈ alkyl (especially 2-ethylhexyl), m is a number from 7 to 29 (in particular 10 bis 16), n is a number from 2 to 4 (especially 2 or 3), p is a number from 2 to 5 (especially 3 or 4) and X is

each is S and L is YY.

An example of a polymeric dithiophosphoric acid hydroxy fatty acid ester according to the invention is a compound having the following repeating unit

¹ m

in which R ₄ , R ₅ , R _e , m, n, p, L and X independently of one another may have the abovementioned meanings.

The molecular weight (weight average, M _w ) of the polymeric Dithiophosphorsäurehydroxyfettsäureester invention is in the range of 1000 to 40,000 g / mol, as determined by gel permeation chromatography (GPC). The viscous to highly viscous polymers usually have a viscosity in the range of 100 to 1000 cSt (centistokes) at a temperature of 40 ⁰ C.

The following examples further illustrate the invention. All percentages are by weight unless stated otherwise. example 1

A polymeric dithiophosphoric acid hydroxy fatty acid ester according to the invention is synthesized according to the first preparation route. a. quantities

* Percent oxirane oxygen content in epoxidized soybean oil b. manufacturing

Epoxidized soybean oil is placed in a glass vessel at room temperature and slowly added with stirring with di-2-ethylhexyldithiophosphorsäure. This heats up the reaction solution. Under countercooling at 80 - 100 ⁰ C, the total amount of di-2-ethylhexldithiophosphorsäure add. After stirring for 30 minutes at 80 ⁰ C, the reaction is concluded off. A pale yellow liquid is obtained. Hydrolyseschutzstabilisator of bis (2, 6-diisopropylphenyl) carbodiimide to give a further 30 minutes, then at 80 ⁰ C with stirring, stirred for as long as until a clear, yellow liquid. Subsequently, for crosslinking (oligomerization), the 2, 5-dimercapto-l, 3, 4-thiadiazole with stirring at 100 ⁰ C added. After 30 minutes of stirring at 100 ⁰ C dissolves the suspension to give a yellow clear liquid which is highly viscous at room temperature. To remove fine particles, the batch is filtered hot through a filter and then filled.

c. Analysis of the product according to the invention

From the IR spectrum (instrument: Perkin Elmer Spectrum One, film between NaCl windows) of the product from Example 1, which is shown in FIG. 3, the bands listed in the following table result.

A ³¹ P-NMR spectrum (200 MHz NMR spectrometer from Bruker) of the product from Example 1 in CDCl _{3 was} taken up, which shows the following characteristic peaks:

δ (ppm) assigned structure 98.17 (RO) ₂ P (S) SR "95 (RO) ₂ P (S) SR"

Furthermore, the product from example 1 was analyzed by means of gel permeation chromatography. The following devices, materials and measurement conditions were used for the GPC analysis:

Detector: refractive index, Schodex RI-71 pump: Spectra Physics P100 column oven: Yasco Column: 3 x Nucleogel GPC 100A + 100A + 50A.

5μ, 300.x 1.1 mm

Column temperature: 35 ° C Injection amount: 10 μl of THF flow agent p.a. (Tetrahydrofuran stabilized) Flow: 1, 0 ml / min Gradient: time% A

0 100

35 100

Sample preparation: approx. 500 mg / 50 ml THF p.a.

Test components: styrene: approx. 250 mg / 50 ml THF p.a.

Polystyrene, MW = 520, 250 mg / 50 ml THF p.a

Polystyrene, MW = 1050, 250 mg / 50 ml THF p.a

Polystyrene, MW = 2000, 250 mg / 50 ml THF p.a

The gel permeation chromatogram thus obtained is shown in FIG. This results in a weight average molecular weight M _w of 6411, a number average molecular weight M _n of 2413, and a molecular weight (centrifuge) M _z of 12230. The polydispersity M _w / M _{n of} the product of Example 1 is 2.6569.

The element contents of the product from example 1 are: phosphorus: 3.51% sulfur: 7.96% Example 2

It is synthesized according to the invention a polymeric dithiophosphoric hydroxyfatty acid ester according to the second preparation route (inverse method).

a. quantities

* Percent oxirane oxygen content in epoxidized soybean oil

b. manufacturing

Epoxidized soybean oil is initially charged at room temperature in a glass vessel, heated to 80 ⁰ C and added to the oligomerization with stirring with 2, 5-dimercapto-l, 3, 4-thiadiazole powder. After stirring for 10 minutes, a pale yellow viscous liquid is obtained. Are then added under counter refrigeration at 80 to 100 ⁰ C within 30 minutes, the di-2 ethylhexyldithiophosphoric acid added. After stirring at 80 ^° C. for 30 minutes, the reaction is complete. A pale yellow liquid is obtained. Subsequently, at 80 ^° C. with stirring, the hydrolysis stabilizer bis (2,6-diisopropylphenyl) - Carbodiimid added and stirred for a further 30 minutes until a clear, yellow liquid is formed. To remove fine particles, the batch is filtered hot through a filter and then filled.

The element contents of the product are:

Phosphorus: 3.52% Sulfur: 7.98%

Example 3

A polymeric dithiophosphoric acid hydroxy fatty acid ester according to the invention is synthesized according to the first preparation route. Instead of 2, 5-dimercapto-l, 3, 4-thiadiazole as in Example 1, a mixture of mono- and di-2-ethylhexylphosphorsäureester (molar ratio 1: 1) is used as a crosslinker. a. quantities

* Percent oxirane oxygen content in epoxidized soybean oil b. manufacturing

Epoxidized soybean oil is placed in a glass vessel at room temperature and slowly added with stirring with di-2-ethylhexyldithiophosphorsäure. This heats up the reaction solution. Under countercooling at 80 - 100 ⁰ C, the total amount of di-2-ethylhexldithiophosphorsäure add in 30 minutes. After stirring at 80 ^° C. for 30 minutes, the reaction is complete. A pale yellow liquid is obtained. Subsequently, the hydrolysis protective stabilizer bis (2, 6-diisopropylphenyl) carbodiimid is added at 80 ⁰ C with stirring and stirred for a further 30 minutes until a clear, yellow liquid. originated. Subsequently, for crosslinking (oligomerization), the mixture of mono- and di-2-ethylhexylphosphorsäureester (molar ratio 1: 1) with stirring at 100 ⁰ C added. After stirring for 30 minutes at 100 ^° C., a yellow clear liquid is obtained, which is highly viscous at room temperature. To remove fine particles, the batch is filtered hot through a filter and then filled.

The element contents of the product are:

Phosphorus: 4.51% Sulfur: 8.23%

Example 4

This example relates to the synthesis of a polymeric Dithiophosphorsäurehydroxyfettsäureesters according to the first preparation route, wherein as in Example 3, a mixture of mono- and di-2-ethylhexylphosphorsäureester (molar ratio 1: 1) used as a crosslinker compound, but no hydrolysis protective stabilizer (bis (2, 6-diisopropylphenyl) carbodiimide) is added.

a. quantities

* Percent oxirane oxygen content in epoxidized soybean oil

b. manufacturing

Epoxidized soybean oil is placed in a glass vessel at room temperature and slowly added with stirring with di-2-ethylhexyldithiophosphorsäure. This heats up the reaction solution. Under countercooling at 80 - 100 ⁰ C, the total amount of di-2-ethylhexldithiophosphorsäure add. After 30 minutes stirring at 8O ⁰ C, the reaction is completed. A pale yellow liquid is obtained. Subsequently, for crosslinking (oligomerization), the mixture of mono- and di-2-ethylhexylphosphorsäureester (molar ratio 1: 1) with stirring at 100 ⁰ C added. After 30 minutes of stirring at 100 ⁰ C to obtain a yellow clear liquid which is highly viscous at room temperature. To remove fine particles, the batch is filtered hot through a filter and then filled. The element contents of the product are:

Phosphorus: 5.0% Sulfur: 10.1%

Example 5

This example again relates to the synthesis of a polymeric Dithiophosphorsäurehydroxyfett- acid ester according to the invention in the first preparation, wherein as in Example 3, a mixture of mono- and di-2-ethylhexylphosphorsäureester (molar ratio 1: 1) is used as a crosslinker. Instead of the epoxidized soybean oil, however, a synthetic epoxidized fatty acid ester (epoxidized propylene glycol dioleate with an epoxide content of 4%) is used.

a. quantities

* Percent oxirane oxygen content in the epoxidized propylene glycol dioleate b. manufacturing

Epoxidized propylene glycol dioleate is initially charged at room temperature in a glass vessel and slowly added with stirring with di-2-ethylhexyldithiophosphorsäure. This heats up the reaction solution. Under countercooling at 80 - 100 ⁰ C, the total amount of di-2-ethylhexldithiophosphorsäure add. After 30 minutes of stirring at 8O ⁰ C, the reaction is complete. A pale yellow liquid is obtained. Hydrolyseschutzstabilisator of bis (2, 6-diisopropylphenyl) carbodiimide to give a further 30 minutes, then at 80 ⁰ C with stirring, stirred for as long as until a clear, yellow liquid. Are then added to cross-link (oligomerization), the mixture of mono- and di-2 ethylhexylphosphorsäureester (molar ratio 1: 1) was added with stirring at 100 ⁰ C. After stirring for 30 minutes at 100 ^° C., a yellowish clear liquid is obtained which is highly viscous at room temperature. To remove fine particles, the batch is filtered hot through a filter and then filled.

The element contents of the product are:

Phosphorus: 3.62% Sulfur: 7.98%

Example 6

First, the wear index of the base oil ISO VG 46 according to DIN 51350/3 was determined. Then base oils ISO VG 46 were tested, which had different concentrations of the product of Example 1. The obtained wear characteristics (diameter of the dome) are summarized in the following table.

Example 7

First, the welding force of the base oil ISO VG 46 according to DIN 51350/2 was determined. Then base oils ISO VG 46 were tested, which had different concentrations of the product of Example 1. The obtained welding force values are summarized in the following table.

Example 8

The wear index of base oils ISO VG 46 according to DIN 51350/3 was determined, to which different amounts of the product from Example 1 or to zinc di-2-ethylhexyl dithiophosphate (hereinafter also referred to as ¹¹ ZDTP ") were added. The obtained wear characteristics (diameter of the dome) are summarized in the following table.

Example 9

The welding power of base oils ISO VG 46 according to DIN 51350/2 was determined, to which different amounts of the product from Example 1 or to zinc di-2-ethylhexyl dithiophosphate were added. The obtained welding force values are summarized in the following table.

Beispiel 10

Example 10

The antioxidant properties of zinc di-2-ethylhexyl dithiophosphate compared to the product of Example 1 in the base oil ISO VG 46 according to ASTM 2272 (Rotating bomb) were determined. The concentration of ZDTP and product from Example 1 in the base oil ISO VG 46 was 0.5% by weight in each case. The results of these investigations are summarized in the following table.

It has been shown that the reaction of substituted dithiophosphoric acids with epoxidized fatty acid esters and subsequent polymerization with crosslinker compounds such as dimercapto-1, 3, 4-thiadiazole or dinonylnaphthalenedisulfonic acids oil-soluble products that are metal-free and due to the readily biodegradable components such as Soya oil has a favorable ecotoxicological profile. At the same time their production is economical by the elimination of expensive filtrations, as is necessary in the preparation of Zinkdialkyldithio- phosphates. In the reaction according to the invention (oligomerization or polymerization), "castor oil-like" structures (hydroxy fatty acid esters) are obtained which have excellent lubricating properties. As can be seen from the application-technical examples 6 to 10, the use of the polymers according to the invention leads to a significant improvement in the wear of the lubricant by about 47%, thereby exceeding the effect of the classical zinc dialkyldithiophosphates. At the same time, the addition of the product according to the invention increases the welding force value of a lubricant and also significantly improves the aging properties of the base oil.

When using the polymers according to the invention, multifunctional additives for the formulation of lubricants are available to the user through significantly improved property profiles. Examples of lubricants include hydraulic oils, engine oils, gear oils, lubricating oils, lubricating greases, metal working oils and industrial oils. In addition to the general suitability of the polymers according to the invention as a lubricant additive, their special use for improving the wear protection effect or the aging stability in lubricants should be emphasized.

Claims

claims 1. A process for the preparation of polyraeren Dithiophosphor- säurehydroxyfettsäureestern, characterized in that (a) an epoxidized fatty acid ester of the formula (I)

(D with A = R ₁ O or H, wherein x is a number from 0 to 6 and R ₁ , R ₂ and R _{3 may be the} same or different and are as defined below: R ₄ - (CH ₂ ) PI (C / H-CH) _n (CH ₂ U-CI? wherein R _{4 is} H or -CH ₃ , m is a number from 1 to 40, n is a number from 1 to 10, p is a number from 0 to 8 and the individual, provided with the index m methylene units (CH ₂ ) and wherein the individual, provided with the index n Epoxidein- units (CHOCH) in any order above the each unit f ( ^CH CH) _n (CH ₂ ) _m ] can be distributed, with a substituted dithiophosphoric acid of formula (II) _D ~ R ₆ -O ^ SH (ID is implemented, wherein R ₅ and R _{6 may be the} same or different and are independently selected from H, alkyl or aryl, provided that at least one of R ₅ and R _{6 is} not H, wherein the fatty acid ester of formula (I) is reacted with the dithiophosphoric acid of formula (II) to form an intermediate with unreacted epoxide groups, and (b) reacting the intermediate with a crosslinker compound to form the polymeric dithiophosphoric hydroxy-hydroxy acid ester wherein the crosslinker compound intermolecularly reacts with two or more epoxide groups. 2. The method according to claim 1, characterized in that in step (a) the ratio of the number of epoxide groups of the fatty acid ester of the formula (I) to the thiol group of dithio phosphoric acid of the formula (II) at least 1: 1, particularly preferably 3: 2 and most preferably 3: 1. 3. The method according to claim 1 or 2, characterized in that the crosslinker compound has the formula (III) L- (XH) ₂ (III) in which L is a molecular unit, -XH is a functional, H-acidic group, wherein X is independently oxygen or sulfur and z is at least 2. 4. A process for the preparation of polymeric Dithiophosphor- säurehydroxyfettsäureestern, characterized in that (a) reacting an epoxidized fatty acid ester of formula (I) as defined in claim 1 with a crosslinker compound, wherein the crosslinker compound intermolecularly reacts with two or more epoxide groups and the fatty acid ester and crosslinker compound are reacted together to form a polymeric intermediate unreacted epoxide groups is formed, and (B) the polymeric intermediate is reacted with a dithio phosphoric acid of formula (II) as defined in claim 1 to form the polymeric Dithiophos- phorsäurehydroxyfettsäureesters. 5. The method according to claim 4, characterized in that in step (a) a crosslinker compound of formula (III) as defined in claim 3 is used. 6. The method according to claim 5, characterized in that the ratio of the number of epoxide groups of the fatty acid ester of the formula (I) to functional, H-acidic groups of the crosslinker compound of the formula (III) is at least 1: 1, more preferably 10: 1 and most preferably 20: 1. 7. The method according to any one of claims 1 to 6, characterized in that x is 1. 8. The method according to any one of claims 1 to 7, character- ized in that the epoxidized fatty acid ester of the formula (I) is derived from epoxidized oils of natural origin. 9. The method according to claim 8, characterized in that the epoxidized oil of natural origin of epoxidized Soybean oil, linseed oil, rapeseed oil, sunflower oil and fish oil. 10. The method according to any one of claims 1 to 9, character- ized in that in the fatty acid ester of the formula (I) A = H is. 11. Process according to claim 10, characterized in that the fatty acid ester of the formula (I) is epoxidized propylene glycol dioleate. 12. The method according to any one of claims 1 to 11, characterized in that the percentage content of oxirane oxygen in the fatty acid ester of the formula (I) is greater than 2 wt .-% and preferably greater than 3 wt .-%. 13. The method according to any one of claims 1 to 12, characterized in that R ₅ and R _{s are} each C ₆ - to C ₈ alkyl. 14. The method according to claim 13, characterized in that R ₅ and R _{6 are} each 2-ethylhexyl. 15. The method according to any one of claims 1 to 14, character- ized in that z in the crosslinker compound of the formula (III) is 2. 16. The method according to claim 15, characterized in that the crosslinker compound of the formula (III) is selected from naphthalenedi-sulfonic acids, aliphatic and / or aromatic saturated dicarboxylic acids, monoalkylphosphoric acid esters, mixtures of monoalkylphosphoric acid esters and dialkylphosphoric acid esters and dimercaptothiadiazoles. 17. The method according to claim 16, characterized in that the crosslinker compound of formula (III) from Dinonylnapha- lindisulfonsäure, 2-Ethylhexylphosphorsäuremonoester, mixtures of 2-Ethylhexylphosphorsäuremonoester and 2-Ethylhexylphosphorsäurediester and 2, 5-dimercapto-l, 3, 4-thiadiazol is selected. 18. The method according to any one of claims 1 to 17, characterized in that before or after step (b), a hydrolysis seschutzmittel is added. 19. The method according to claim 18, characterized in that the hydrolysis protection agent is an oil-soluble and sterically hindered Arylcarbodiimid. 20. The method according to claim 19, characterized in that the arylcarbodiimide is bis (2,6-diisopropylphenyl) carbodiimide. 21. A polymer dithiophosphoric acid hydroxy fatty acid ester obtainable by a process according to any one of claims 1 to 20. 22. A polymer dithiophosphoric acid hydroxy fatty acid ester, characterized in that it contains the following regularly repeating unit: R ₄ - (CH ₂ ) _p -

wherein R _{4 is} independently H or -CH ₃ , Egg the formula H OH

having, E _{2 is} the formula X I L

in which L is a molecular unit and X is independently oxygen or sulfur, E _{3 is} the formula

having, wherein R ₅ and R _{6 may be the} same or different and are independently selected from H, alkyl or aryl, provided that at least one of R ₅ and R _{6 is} not H, wherein each m is a number from 1 to 40, n is a number from 1 to 10, p is a number from 0 to 8 and the individual, provided with the index m methylene units (CH ₂ ) and the individual, with the index n provided units E ₁ , E ₂ or E _{3 may be distributed} in any order over the respective unit [(CH ₂ ) _m (Ei) _n ] and wherein the number of repeating units is in particular at least 2. Polymeric Dithiophosphorsäurehydroxyfettsäureester according to claim 22, characterized in that R ₅ and R _{6 are} each C ₆ - to C ₈ alkyl. Polymeric Dithiophosphorsäurehydroxyfettsäureester according to claim 23, characterized in that R ₅ and R _{6 are} each 2-ethylhexyl. 25. Polymer Dithiophosphorsäurehydroxyfettsäureester according to any one of claims 22 to 24, characterized in that m is a number from 7 to 29 and preferably from 10 to 16. 26. Polymeric Dithiophosphorsäurehydroxyfettsäureester according to any one of claims 22 to 25, characterized in that n is a number from 2 to 4 and preferably 2 or 3. 27. Polymeric Dithiophosphorsäurehydroxyfettsäureester according to any one of claims 22 to 26, characterized in that p is a number from 2 to 5 and preferably 3 or 4. 28. A polymer dithiophosphoric acid hydroxy fatty acid ester according to any one of claims 22 to 27, characterized in that X is in each case S and L is.

29. Use of the polymeric Dithiophosphorsäurehydroxy fatty acid ester according to any one of claims 21 to 28 as a lubricant additive. 30. Use of the polymeric Dithiophosphorsäurehydroxy fatty acid ester according to any one of claims 21 to 28 for Improvement of the wear protection effect of lubricants. 31. Use of the polymeric Dithiophosphorsäurehydroxy fatty acid ester according to any one of claims 21 to 28 for Improvement of the aging stability of lubricants. 32. Use according to one of claims 29 to 31, characterized in that the lubricant from hydraulic oils, Mo oils, gear oils, lubricating oils, greases, metalworking oils and industrial oils. 33. A lubricant containing the polymeric Dithiophosphorsäury droxyfettsäureester according to any one of claims 21 to 28. 34. A lubricant according to claim 33, characterized in that the lubricant is selected from the lubricants as defined in claim 32.