WO2014044489A1

WO2014044489A1 - Ester with carbonate groups

Info

Publication number: WO2014044489A1
Application number: PCT/EP2013/067549
Authority: WO
Inventors: Stefan Buchholz; Michael Grass; Benjamin WOLDT; Andreas Gevers; Benjamin SCHÄFFNER; Matthias Blug; Andreas Martin; Mykola Polyakov; Angela KÖCKRITZ
Original assignee: Evonik Industries Ag
Priority date: 2012-09-24
Filing date: 2013-08-23
Publication date: 2014-03-27
Also published as: DE102012217195A1

Abstract

The invention relates to n-pentylester und iso-pentylester with at least one cyclic carbonate group on the acid chain, to a method for the production and use of the ester as a plasticizer fpr polymers.

Description

Ester with carbonate group

The invention relates to an ester having at least one carbonate group on the acid chain. Furthermore, a method for producing such an ester, as well as the use of the ester as a plasticizer for polymers.

In the patent documents US 2,858,286, US 2,826,591 and GB 786,657 carbonated fatty acid esters are described with an alcohol radical of even-numbered alcohols. In the preparation described here, phosgene (carbon monoxide dichloride) was always used. Phosgene is a very poisonous gas for humans.

The task consisted firstly of providing further esters with one or more carbonate groups which have good softening properties, and secondly to develop a production process in which the use of phosgene can be dispensed with.

The object is achieved by an ester according to claim 1.

Esters according to the formula I:

wherein R ^{1 is} a carbon chain having 7 to 25 carbon atoms, and

the carbon chain R ¹ additionally has at least one carbonate group, and

R ^{2 is} a radical selected from: n-pentyl, iso-pentyl.

The "additional" is meant to indicate that the carbon atom of the carbonate group is not included in the carbon chain, so for linolenic acid R ^{1 is} always a carbon chain of 17 carbon atoms, regardless of how many of the three

Double bonds were converted to a carbonate.

In one embodiment, R ^{2 is} n-pentyl. In one embodiment, the acid portion of the ester was derived from a vegetable oil. This can be seen for example on an ester mixture, which is a

Has acid distribution, as occurs in a vegetable oil. For example, soybean oil or rapeseed oil can be used as the source of the fatty acids, as well as other vegetable oils. The naturally occurring fatty acids (mixtures) are obtained

for example, by ester cleavage or transesterification of vegetable oils.

In one embodiment, no double bond is present directly in the acid chain. Direct in the acid chain means that two carbon atoms in the acid chain, for example C9 and C10, are linked by a double bond. This does not preclude that in a side chain which branches off from the acid chain, a double bond is present.

In one embodiment, the ester has the following structure:

where x is a number from 1 to 1 1.

Preferably, x is from 4 to 11, more preferably from 7 to 11.

In another embodiment, the ester has the following structure:

where y is a number from 1 to 8.

Preferably, y is a number from 2 to 8, more preferably a number from 4 to 8. In another embodiment, the ester has the following structure:

where z is a number from 1 to 5.

Preferably, z is 1.

In one embodiment, R ^{1 is} a carbon chain having 1 1 to 21 carbon atoms. That is, for the esterification, an acid having 12 to 22 carbons in the acid chain was used.

Regardless, the claimed ester may be part of a mixture which also includes esters whose acids have a different acid chain length.

In one embodiment, R ^{1 is} a carbon chain of 17 carbon atoms. That is, for esterification, an acid of 18 carbons was used in the acid chain.

In one embodiment, the ester has the following structure:

In another embodiment, the ester has the following structure:

In another embodiment, the ester has the following structure:

In addition to the ester itself and its use is claimed.

Use of one of the esters described above as a plasticizer for a polymer selected from: polyvinyl chloride, polyvinylidene chloride, polylactic acid, polyurethanes,

Polyvinyl butyral, polyalkyl methacrylates or their copolymers.

Preference is given to the use of one of the esters described above as a plasticizer for polyvinyl chloride.

Furthermore, a process for producing the above-described esters is claimed.

A process for the preparation of a previously described ester comprising the process steps: a) presentation of an epoxidized fatty acid ester in a reaction vessel,

b) introducing carbon dioxide into the reaction vessel,

c) heating the reaction mixture in the reaction vessel. Here, for example, an autoclave can serve as a reaction vessel.

In a variant of the method, a phase transfer catalyst is added to the reaction mixture. Preference is given to using a phase transfer catalyst which comprises a

ethylene-ether bridged compound (-O-C ₂ H ₄ -O-). Crown ethers or glycols are particularly preferably used.

In a variant of the method, a crown ether is added to the reaction mixture. Here, 18-crown-6 (= 18-crown-6) is preferred.

In a variant of the method, an alcohol is added to the reaction mixture with a branched or linear alkyl chain having 1 to 8 C atoms. Here, alcohols having an alkyl chain of 1 to 3 carbon atoms are preferred. In a variant of the method, an iodide is added to the reaction mixture. In this case, potassium iodide is preferred.

In a variant of the method, after reaching the reaction temperature, the pressure in the reaction vessel is increased by adding liquid carbon dioxide.

The following examples are intended to illustrate the invention without limiting its scope, which will be apparent from the description.

Examples

Synthesis of epoxidized fatty acid esters

Example 1: Preparation of an epoxidized fatty acid n-propyl ester by transesterification of epoxidized soybean oil with n-propanol using sodium (Na)

100 mL of n-propanol were placed in a 250 mL round bottom flask. 1.7 g (0.8% by weight) of sodium were slowly added in small portions with stirring and stirred for 4 hours at room temperature. The solution is diluted with 50 mL of n-propanol and taken with 250 g of epoxidized soybean oil in a 2 L round bottom flask (equipped with a water bath and a KPG stirrer) transferred. Subsequently, the flask was heated to 50 ° C with stirring (200 rpm).

The reaction mixture was stirred for 2.5 hours at 350 rpm and 50 ° C. A portion of the resulting glycerol could be deposited after 2 hours of service life of the remaining reaction mixture at room temperature.

The mixture was then transferred to a 2 L separatory funnel. To the mixture was added 400 ml of water at a temperature of 80 ° C and shaken thoroughly. After separation of the two phases, the aqueous phase was separated. This extraction procedure was repeated 4 more times until the aqueous phase was pH neutral. The excess alcohol was then removed by vacuum distillation on

Rotary evaporator removed at 80 ° C. The product was used without further work-up steps for the preparation of cyclic carbonates according to Example 9. Example 2: Preparation of epoxidized fatty acid n-propyl ester by transesterification of epoxidized soybean oil with n-propanol using sodium methoxide (NaOMe)

In a 250 ml round bottom flask, 300 ml of n-propanol were charged. 2.0 g (0.5% by weight)

Sodium methoxide (Aldrich) was slow in small portions with stirring

added and stirred for 4 hours at room temperature and then diluted with 125 ml_ n-propanol. Subsequently, the mixture was transferred together with 400 g of epoxidized soybean oil in a 2 L round bottom flask (equipped with a water bath and a KPG stirrer). Subsequently, the flask was heated to 50 ° C with stirring (200 rpm).

The mixture was then transferred to a 2 L separatory funnel. To the mixture was added 400 ml of water at a temperature of 80 ° C and shaken thoroughly. The aqueous phase was separated. This extraction procedure was repeated 4 more times until the aqueous phase was pH neutral. The excess alcohol was then removed by vacuum distillation on a rotary evaporator at 80 ° C. The Product was used without further work-up steps for the preparation of cyclic carbonates according to Example 9.

Analogously to Examples 1 and 2, other esters were produced according to Table 1.

Table 1: Synthesis of various epoxidized fatty acid esters of n-alcohols under

Use of sodium methoxide or sodium.

catalyst screening

Example 9: Potassium iodide in combination with crown ethers (18-Crown-6) in the carbonation using epoxidized fatty acid methyl esters

2.5 g of epoxidized fatty acid methyl esters (Nexo E1, Nexoleum), 0.1257 g (5% by weight) of potassium iodide (catalyst) (Aldrich) and 0.0881 g were charged into a 25 ml autoclave (Parr) equipped with a KPG stirrer (3.5% by weight) crown ether (co-catalyst) (18-Crown-6) (Aldrich) and then the autoclave sealed. Subsequently, a system for filling the carbon dioxide (C0 ₂ ) was connected (Modified HPLC pump from. Shimadzu and a C0 ₂ dip tube from the company Air Liquide). The autoclave was rinsed three times with C0 ₂ (about 10 bar) before a pressure of about 35 bar was set. The initial stirring speed was set to 300 revolutions per minute and the autoclave was heated to 100 ° C. After reaching the temperature, liquid C0 _{2 was} charged until a pressure of 100 bar was reached in the autoclave. The stirring speed was increased to 500 revolutions per minute. After 17 hours, the stirrer was switched off and the autoclave cooled to room temperature. C0 ₂ was slowly drained from the system and the reaction vessel opened. To determine sales, measurements were made using NMR and gas chromatography performed. For gas chromatographic measurements, the product was transferred to a 25 ml graduated cylinder and made up with methanol. In the investigations, a conversion of 90% and a selectivity> 99% were found. The degree of carbonation is calculated as follows from the analysis by means of gas chromatography (GC) and ¹ H-NMR.

¹ H NMR analysis was performed on an AV 300 (Bruker) spectrometer, 300 MHz

(Solvent: CDCI ₃ ). The epoxide conversion was determined by comparing the integrals between 2.8 and 3.1 ppm (hydrogen atoms in the epoxy ring) with the integral between 4.2 and 5.1 ppm (hydrogen atoms in the carbonate ring). In addition, that became

Ratio of epoxide ring protons to methylene group protons (-CH ₂ -COOR) at 2.29 ppm in the product mixture compared with the ratio in the starting material. A similar procedure was reported by Doli et al. {Green Chem. 2005, 7, 849) and by Aerts et al. {J. At the. Chem. 0/7 Soc. 2004, 81, 841). The evaluation of the NMR spectra allows the determination of the

Total sales of epoxides and the overall yield of carbonates. The determination of the conversion and the selectivity of epox. Me-oleate or epox. Me linoleate was carried out by GC analysis. For this purpose, a GC-2012 chromatograph (Shimadzu) with an HP-5 (15 m × 1.5 × 0.5 × 0.53 mm) column (He flow: 2.5 ml / min) and FID could be used. The solvent used was ethyl acetate. The determination of the conversion of the individual fatty acid esters was carried out by integration of the various signals of the individual epoxidized and carbonated fatty acid esters. The internal standard used was the palmitic acid contained in the solution, which is internal to the reaction.

Analogous to Example 9, further investigations of the catalyst were carried out according to Table 2. TABLE 2 Examinations of various suitable catalysts for the carbonation of epoxidized fatty acid methyl esters (Nexo E1, Nexoleum).

In a modification of Example 9, Example 24 employed a bimetallic aluminum-salen catalyst having the following structure:

[(SalenJAIfeQ

The catalyst was used in combination with tetrabutylammonium bromide

Phase transfer catalyst used. Under analogous conditions to Example 9, the aluminum-salen catalyst with 1.3% by weight and tetrabutylammonium bromide as co-catalyst was likewise used at 1.3% by weight. It was after 19 hours

Carbonation of 80% and a selectivity> 99% achieved. Analogously to Example 9, according to Table 1 1 further investigations of the

Phase transfer catalyst performed. In this case, potassium iodide was analogous to Example 9 with 3.5 Wt .-% used as a catalyst and the type and amount of co-catalyst varies. The suitability of different alcohols as phase transfer catalysts was investigated.

Table 1 1: Investigations of various suitable co-catalysts for the carbonation of epoxidized fatty acid methyl esters (Nexo E1, Nexoleum) with potassium iodide.

The experiments in Table 1 1 clearly show that even short-chain alcohols such as ethanol and methanol can be used successfully in the reaction. In particular, methanol has high suitability as a phase transfer catalyst and solvent for potassium iodide.

Methanol may be preferable to other phase transfer catalysts because of the lower cost and ease of separation by distillation.

In a modification of Example 9, further investigations of the phase transfer catalyst were carried out according to Table 12 regarding its reactivity in heterogeneous solution. The experimental conditions correspond to those of Example 9, only the reaction time was shortened to 6 hours. By admixing water can be a two-phase

Reaction system can be achieved, whereby the separation and reuse of the catalyst can be significantly simplified. Table 12:

PEG: polyethylene glycol The experiments show that a combination of phase transfer catalysts with water is also possible. The exact adjustment of the amount of water in the binary mixture is essential to achieve on the one hand the formation of a two-phase system at the end of the reaction, and on the other to achieve an efficient implementation. In particular, mixtures of polyethylene glycol 400 and water in ratios of between 19: 1 and 1: 1 are preferred.

Example 13: Polyoxometalates of the type

(TBA = tetrabutylammonium) in the carbonation using 9,10-epoxystearic acid methyl ester

In a 25 ml autoclave (Parr) equipped with a KPG stirrer 2.5 g of 9,10-Epoxystearinsäuremethylester (techn. Fa Hobum), 0.565 g (about 2 mol%)

(The synthesis was carried out in analogy to the literature procedure of Yasuda et al., J. Catal. 2005, 233, 1 19-122.) and the autoclave subsequently closed. Subsequently, a system for filling the carbon dioxide (C0 ₂ ) was connected (Modified HPLC pump from. Shimadzu and a C0 ₂ dip tube from the company Air Liquide). The autoclave was rinsed three times with C0 ₂ (about 10 bar) before a pressure of about 35 bar was set. The initial stirring speed was set to 300 revolutions per minute and the autoclave was heated to 100 ° C. After reaching the temperature, liquid C0 _{2 was} charged until a pressure of 100 bar was reached in the autoclave. The stirring speed was increased to 500 revolutions per minute. After 17 hours, the stirrer was switched off and the autoclave cooled to room temperature. C0 ₂ was slowly drained from the system and the reaction vessel opened. To determine the sales measurements were carried out by NMR and gas chromatography. For gas chromatographic measurements, the product was transferred to a 25 mL graduated cylinder and made up with methanol. In the investigations, a conversion of 33% and a selectivity> 99% were found.

Analogous to Example 13, further investigations of the catalyst were carried out according to Table 2.

TABLE 3 Examinations of Various Suitable Polyoxometalate Catalysts for the Carbonation of 9,10-Epoxystearic Acid Methyl Ester (Techn., Fa. Hobum). Ex. Catalyst degree of carbonation selectivity

No.

14 (TBA a-SiWuOagCo]. (C ₇ H ₈ ) 69%> 99%

(TBA = tetrabutylammonium)

15 (THAfela-SiWuOagFeMC Hek 73%> 99

(THA = tetraheptylammonium)

Synthesis of Carbonates for Plasticizer Studies Example 16: Synthesis of Carbonates from Epoxidized Fatty Acid Methyl Esters by

Use of C0 ₂ and a catalyst

153.4 g of epoxidized fatty acid methyl esters (Nexo E1, Nexoleum) and 7.69 g

Tetrabutylammonium bromide (Aldrich) was charged into a 250 ml autoclave (Parr) equipped with a KPG stirrer and the autoclave was tightly closed. Subsequently, a system for filling the carbon dioxide (C0 ₂ ) was connected (Modified HPLC pump from. Shimadzu and a C0 ₂ dip tube from the company Air Liquide). The autoclave was rinsed three times with C0 ₂ (about 10 bar) before a pressure of about 35 bar was set. The stirring speed was set to 350 revolutions per minute and the autoclave was heated to 100 ° C. After reaching the reaction temperature, the pressure was increased by the addition of liquid C0 ₂ to 105 bar and the stirring speed increased to 500 revolutions per minute. The system was held at pressure and temperature for 6 days to allow full conversion.

After 6 days reaction time, the autoclave was cooled to room temperature and excess C0 _{2 was} slowly drained from the system. The reaction mixture was removed from the autoclave and dissolved in 200 ml of ethyl acetate. Potassium iodide and the crown ether were removed by extraction in a 2 L separatory funnel with 4 x 200 mL water.

Subsequently, the product mixture was dried over sodium sulfate. Ethyl acetate was finally removed on a rotary evaporator at 70 ° C, 10 mbar for 5 hours. A conversion> 99% and a selectivity with respect to the carbonates of> 99% was determined.

Example 17: Synthesis of carbonates from epoxidized fatty acid isopentyl ester by

Use of C0 ₂ and a catalyst 169.5 g of epoxidized fatty acid isopentyl esters (PLS Green 5, Petrom) and 8.4 g of potassium iodide (Aldrich) and 5.4 g of Kronether (18-Crown-6) (Aldrich) were in a 250 mL

Autoclaves (Parr) equipped with KPG stirrer, filled and the autoclave tightly closed. Subsequently, a system for filling the carbon dioxide (C0 ₂ ) was connected (Modified HPLC pump from. Shimadzu and a C0 ₂ dip tube from the company Air Liquide). The autoclave was rinsed three times with C0 ₂ (about 10 bar) before a pressure of about 35 bar was set. The stirring speed was set to 350 revolutions per minute and the autoclave was heated to 100 ° C. After reaching the reaction temperature, the pressure was increased by the addition of liquid C0 ₂ to 105 bar and the stirring speed increased to 500 revolutions per minute. The system was held at pressure and temperature for 12 hours to allow full conversion.

After 1 12 hours reaction time, the autoclave was cooled to room temperature and excess C0 ₂ slowly drained from the system. The reaction mixture was removed from the autoclave and dissolved in 200 mL of ethyl acetate. Potassium iodide and the crown ether were removed by extraction in a 2 L separatory funnel with 4 x 200 mL of water.

Subsequently, the product mixture was dried over sodium sulfate. Ethyl acetate was finally removed on a rotary evaporator at 70 ° C, 10 mbar for 5 hours. A conversion of> 99% and a selectivity with respect to the carbonates> 99% was determined.

Analogous to Example 17, further samples for the application tests were carried out according to Table 4.

Table 4: Synthesis of various carbonated fatty acid derivatives in the presence of

Potassium iodide and crown ether (18-Crown-6).

Comparative tests for the Plastisol application:

1. Preparation of the plastisol

It was made a PVC plastisol, as for example for the production of

Covering films is used for floor coverings. The information in the Plastisolrezepturen are each in parts by weight. Vestolit B 7021 -Ultra was used as PVC. When

Comparative substances were diisononyl phthalate (DINP, VESTINOL 9 Fa. Evonik

Industries) and the carbonate of the fatty acid methyl ester (carb FSE methyl) (from Example 16). The plasticizers used in addition to the comparison substances were prepared according to Examples 17-23. The formulations of the polymer compositions are listed in Table 5. Table 5: Formulations of the polymer compositions

^* Polymer composition comprising an ester of the invention

In the formulations, the alkyl radical (corresponds to the former alcohol, which was used for the transesterification or transesterification) of the fatty acid ester is shown in parentheses. Of the

Carbonation degree is> 95% for all carbonates. In addition to the 50 parts by weight of plasticizer each recipe contains 3 parts by weight of an epoxidized soybean oil as a co-stabilizer (Drapex 39, Galata), and 2 parts by weight of a Ca / Zn-based heat stabilizer (Mark CZ 149, Galata).

The plasticizers were heated to 25 ° C prior to addition. First, the liquid ingredients and then the powdered ones were weighed into a PE beaker. By hand, the mixture was stirred with an ointment spatula so that no unwetted powder was present. The mixing cup was then clamped in the clamping device of a dissolver stirrer. Before immersing the stirrer in the mixture, the speed was set to 1800 rpm. After switching on the stirrer, stirring was continued until the temperature at the digital indicator of the thermocouple reached 30.0 ° C. This was to ensure that the homogenization of the plastisol at a defined

Energy input was achieved. Thereafter, the plastisol was immediately heated to 25.0 ° C. 2. Measurement of plastisol viscosities

The viscosity of the PVC plastisols was measured with a Physica MCR 101 (Anton Paar) using the rotation mode and the "CC27" measuring system.

The plastisol was first homogenized again in the batch tank by stirring with a spatula, then filled into the measuring system and measured isothermally at 25 ° C. During the measurement, the following points were controlled:

1 . A pre-shear of 100 s ^"1 for the period of 60 s at which no measured values were recorded (to level any thixotropic effects that may occur).

2. A shear rate down ramp, starting at 200 s ^"1 and ending at 0.1 s ^{" 1} , divided into a logarithmic series of 30 steps each with a 5 second measurement point duration.

The measurements were usually carried out (unless stated otherwise) after 24 h storage / maturation of the plastisols. Between measurements, the plastisols were stored at 25 ° C.

The viscosities for the PVC pastes at a shear rate of 100 s ^-1 are listed in the following Table 6. The paste number here correlates with the recipe number from Table 5.

Table 6:

In comparison, pastes 4, 5, 6, 7 and 8 have a lower paste viscosity than pastes 2 and 3 which comprise the carbonated fatty acid methyl or propyl esters.

PVC pastes based on a polymer composition according to the invention (4 and 5), in comparison with an analog paste based on the carbonated fatty acid methyl ester, regardless of the shear rate, a lower shear viscosity and thus improved processability.

3. Volatility The volatility of the pure plasticizers was determined using the halogen dryer HB 43-S from Mettler Toledo. Before the measurement was an empty clean aluminum tray in

Weighing plate placed. Thereafter, the aluminum tray was tared with a nonwoven and about five grams of plasticizer pipetted on the fleece and weighed exactly.

By closing the heating module, the measurement was started and the sample was heated from room temperature to 200 ° C at the maximum heating rate (default setting). The corresponding mass loss due to evaporation was automatically determined by weighing every 30 seconds. After 10 minutes, the measurement was automatically stopped by the device.

From each sample, a duplicate determination was made. The mean values of the results are shown in Table 7. The plasticizer number (WM No.) correlates with the recipe number from Table 2.

Table 7:

The polymer composition of the pastes 2 and 3 shows a significantly higher mass loss than those polymer compositions of the pastes 4 to 8. Significantly increased mass loss greatly limits the applicability of the plasticizers.

4. Water resistance

Aging resistance under various environmental conditions is another key quality criterion for PVC plasticizers. In particular, the behavior towards water (water absorption & washout of formulation ingredients) and against elevated temperatures (evaporation of formulation components & thermal aging) offers an insight into the aging resistance.

If a plastic article absorbs water to a greater extent, this changes its material properties on the one hand, and also its optical appearance (e.g.

Clouding). A high water absorption is therefore generally undesirable. The

Washout is an additional criterion for the permanence of

Formulation ingredients under conditions of use. This is especially true for

Stabilizers, plasticizers and / or their components, as a reduction in concentration in Plastic articles in these formulations ingredients both deteriorate the material properties and can dramatically reduce the life.

For the determination of the water resistance, gelled 1 mm polymer films were produced from the corresponding plastisols (gelling conditions in Mathisofen:

200 ° C / 2 min.). As test specimen, foil circles with a diameter of 3 cm were cut out. Before the water storage, the test specimens were stored for 24 hours in a desiccant equipped with desiccant (KC dry beads, BASF SE) at 25 ° C. The initial weight (weighed in) was determined to the nearest 0.1 mg with an analytical balance. The test specimens were then stored in a shaker bath (type "WNB 22" with Peltier cooling device "CDP", Memmert GmbH) filled with demineralised (VE) water at a temperature of 30 ° C. for 7 days with sample holders under the water surface and moved continuously , Subsequently, the test specimens were stored for 24 hours in a desiccant equipped with desiccant (KC dry beads) desiccator at 25 ° C and then weighed out (final weight = weight after drying). From the difference to the weighing in front of the

Water storage, the percentage mass loss was calculated by water storage (equivalent to loss by leaching).

The results are shown in Table 8. The test piece number correlates with the recipe number from Table 5.

Table 8:

25

The mass loss of the test specimens 2 and 3 is significantly increased compared to the mass loss of the remaining specimens 4 to 7 and 1. Significantly increased mass losses severely limit the applicability of the plasticizers. Because of the too high paste viscosity, the high volatility and the bad

Water storage, methyl (2) and propyl (3) esters of carbonated fatty acids can not be used as universal plasticizers ("general purpose" plasticizers). 5. gelling behavior

The gelling behavior of the pastes was investigated in the Physica MCR 101 in the

Oscillation mode with a plate-plate measuring system (PP25), which

shear-voltage controlled, made. An additional tempering hood was connected to the unit to provide a homogeneous heat distribution and a

to achieve a uniform sample temperature.

The following parameters have been set:

Mode: Temperature gradient

Start temperature: 25 ° C

End temperature: 180 ° C

Heating / cooling rate: 5 ° C / min

Oscillation frequency: 4-0.1 Hz ramp logarithmic

Angular frequency Omega: 10 1 / s

Number of measuring points: 63

Measuring point duration: 0.5 min

Automatic gap tracking F: 0 N

Constant measuring point duration

Gap width 0.5 mm

Carrying out the measurement:

On the lower measuring system plate, a drop of the paste to be measured was applied with the spatula free of air bubbles. Care was taken to ensure that, after moving the measuring system, some paste could swell evenly out of the measuring system (no more than approx. 6 mm around). Then the tempering hood was positioned over the sample and the measurement started. The so-called complex viscosity of the paste was determined as a function of the temperature. Since a certain temperature is reached in a period (determined by the heating rate of 5 ° C / min.), In addition to the

Gelling temperature also get a statement about the gelling speed of the measured system. Onset of gelling was evident in a sudden sharp increase in complex viscosity. The earlier this viscosity increase starts, the better the gelling ability of the system.

From the obtained measuring curves the temperatures are taken, which are needed to reach complex viscosities of 1000 or 25000 mPas. In addition was the maximum viscosity was recorded, since in most cases it correlates with the compatibility between plasticizer and polymer.

The results are shown in Table 9. The paste number here correlates with the recipe number from Table 5.

Table 9:

gelling:

Compared with paste 1 containing DINP, pastes 4 and 5 comprising an ester of the present invention exhibit much faster gelation. The gelling of the pastes 4 and 5 also proceeds faster than the gelling of the pastes 6 and 7. This represents a distinct advantage of the pastes comprising an ester of the invention as a plasticizer. Furthermore, the measured maximum viscosity of the pastes 4 and 5 reaches the highest values.

6. Softening effect

The Shore hardness is a measure of the softness of a specimen. The further a standardized needle can penetrate into the sample body during a certain measuring period, the lower the measured value will be. The plasticizer with the highest efficiency gives the lowest value for the Shore hardness with the same amount of plasticizer. Since in practice formulations / formulations are often adjusted to a specific Shore hardness or

can be optimized, with very efficient plasticizers therefore a certain proportion can be saved in the recipe, which means a cost reduction for the processor.

To determine the Shore hardnesses, the pastes produced as described above were poured into circular molds made of brass with a diameter of 42 mm (weight: 20.0 g). Then the pastes in the molds in the convection oven were gelled at 200 ° C for 30 minutes, after cooling, and stored for at least 24 hours in the climatic chamber (25 ° C) before the measurement. The thickness of the discs was about 12 mm.

The hardness measurements were carried out in accordance with DIN 53 505 with a Shore A measuring device from Zwick-Roell, the measured value was read off in each case after 3 seconds. Measurements were taken at three different sites on each test specimen and an average was formed.

The results are shown in Table 10. The test piece number here correlates with the recipe number from Table 5. Table 10:

Compared to the test specimens 1, 4 and 5, the test specimens 6 to 8 have increased Shore A hardness, ie a lower "softness." With the plasticizers according to the invention, it is possible to produce PVC mixtures which have a better efficiency than when using the As a result, plasticizer can be saved, which leads to lower formulation costs, which in turn represents a clear advantage over the other carbonated fatty acid esters.

The n-pentyl or iso-pentyl esters of carbonated fatty acids thus have clear advantages in terms of their plasticizer properties compared to the esters of other alcohols.

Claims

claims:

1 . Esters according to the formula I:

wherein R ^{1 is} a carbon chain having 7 to 25 carbon atoms, and the carbon chain R ¹ additionally has at least one carbonate group, and R ^{2 is} a radical selected from: n-pentyl, iso-pentyl.

2. Ester according to claim 1,

where R ^{2 is} n-pentyl.

3. Ester according to one of claims 1 or 2,

wherein the acid portion of the ester was derived from a vegetable oil.

4. Ester according to one of claims 1 to 3,

where no double bond is present directly in the acid chain.

5. Ester according to one of claims 1 to 4,

which has the following structure:

where x is a number from 1 to 1 1.

6. Ester according to one of claims 1 to 4,

which has the following structure:

where y is a number from 0 to 8.

7. Ester according to one of claims 1 to 4,

which has the following structure:

where z is a number from 1 to 5.

8. Ester according to one of claims 1 to 5,

wherein R ^{1 is} a carbon chain having 1 1 to 21 carbon atoms.

9. Ester according to one of claims 1 to 7,

where R ^{1 is} a carbon chain of 17 carbon atoms.

10. Use of an ester according to any one of claims 1 to 9,

as plasticizer for a polymer selected from: polyvinyl chloride, polyvinylidene chloride, polylactic acid, polyurethanes, polyvinyl butyral, polyalkyl methacrylates or copolymers thereof.

1 1. Use of an ester according to any one of claims 1 to 9,

as a plasticizer for polyvinyl chloride.

12. A process for producing an ester according to any one of claims 1 to 9,

comprising the method steps:

a) presentation of an epoxidized fatty acid ester in a reaction vessel,

b) introducing carbon dioxide into the reaction vessel,

c) heating the reaction mixture in the reaction vessel.

13. The method according to claim 12,

wherein a phase transfer catalyst is added to the reaction mixture.

14. The method according to any one of claims 12 or 13,

wherein an iodide is added to the reaction mixture.

15. The method according to any one of claims 12 to 14,

wherein after reaching the reaction temperature, the pressure in the reaction vessel is increased by the addition of liquid carbon dioxide.