POLYSULFIDE ADDITIVE, METHOD FOR PRODUCTION THEREOF AND USE THEREOF IN RUBBER MIXTURES

Abstract

The present invention relates to polysulfides of the formula (I)

##STR00001##

where the cations K.sub.1.sup.+ and K.sub.2.sup.+ are each independently any monovalent cation or the fraction of any polyvalent cation which corresponds to a positive charge of one, and n is 2, 3, 4, 5, 6, these having a low residual acidity, and to processes for producing these polysulfide mixtures, to the use of the polysulfides of the formula (I) in rubber mixtures, to the corresponding rubber mixtures, to rubber vulcanizates produced therefrom and to the use thereof.

Claims

1. Polysulfides of the formula (I) ##STR00015## where: the cations K.sub.1.sup.+ and K.sub.2.sup.+ are each independently any monovalent cation or a fraction of any polyvalent cation which corresponds to a positive charge of one, and a portion of the polysulfides of the formula (I) have n=4, and an additional portion of the polysulfides of the formula (I) have n=2, 3, 5 and/or 6, and the portion of polysulfides of the formula (I) with n=4, based on the total amount of polysulfides of the formula (I), is more than 80%.

2. The polysulfides as claimed in claim 1, wherein the portion of polysulfides of the formula (I) with n=4, based on the total amount of polysulfides of the formula (I), is more than 90%.

3. The polysulfides as claimed in claim 1, wherein the cations K.sub.1.sup.+ and K.sub.2.sup.+ are each independently H.sup.+, an alkali metal cation, alkaline earth metal cation, a fraction of a rare earth metal cation which corresponds to a positive charge of one, or Zn.sup.2+.

4. The polysulfides as claimed in claim 1, wherein a mixture of 10 g of polysulfides of the formula (I) in 100 ml of water, after reflux for 30 min and subsequent cooling to 25 C. within 60 min, has a conductivity of <5 mS/cm.

5. The polysulfides as claimed in claim 1, wherein a mixture of 10 g of polysulfides of the formula (I) and 100 ml of water, after being refluxed at standard pressure for 30 min and then cooled down to 25 C. within 60 min, has a pH of >2.

6. The polysulfides as claimed in claim 1, wherein the polysulfides of the formula (I) have a total chlorine content <1%.

7. Polysulfides as claimed in claim 1, wherein the cations K.sub.1.sup.+ and K.sub.2.sup.+ are each independently H.sup.+, or Zn.sup.2+, and the polysulfides have a total chlorine content <0.3%.

8. Polysulfides as claimed in claim 1, wherein the cations K.sub.1.sup.+ and K.sub.2.sup.+ are each independently H.sup.+, or Zn.sup.2+, the polysulfides have a total chlorine content <0.03%, and a mixture of 10 g of polysulfides in 100 ml of water, after reflux for 30 min and subsequent cooling to 25 C. within 60 min, has a pH >2 and a conductivity of <1 mS/cm.

9. The polysulfides as claimed in claim 1, wherein: K.sub.1.sup.+ and K.sub.2.sup.+ are each H.sup.+, the melting range of the polysulfides ends at at least 300 C., where the end of the melting range is determined at a heating rate of 1 C./min, starting from 290 C.; and the polysulfides have a dominant signal in the x-ray diffractogram (Cu K-alpha radiation) at a diffraction angle 2theta of 27.2+/0.1.

10. The polysdulfides as claimed in claim 1, wherein: K.sub.1.sup.+ and K.sub.2.sup.+ are each H.sup.+, the polysulfides have a total chlorine content of <0.03%; 96-99% of the polysulfides of the formula (I) are polysulfides of the formula (I) with n=4; the polysulfides have a melting range ending at at least 304 C., where the end of the melting range is determined at a heating rate of 1 C./min, starting from 290 C.; and the polysulfides have a dominant signal in the x-ray diffractogram (Cu K-alpha radiation) at a diffraction angle 2theta of 27.2 +/0.1; and a mixture of 10 g of the polysulfides of the formula (I) in 100 ml of water, after reflux for 30 min and subsequent cooling to 25 C. within 60 min, has a pH of 3.4-6.2 and a conductivity of <1 mS/cm.

11. A process for preparing the polysulfides as claimed in claim 1, the process comprising: a) reacting 2-mercaptobenzoic acid with S.sub.2Cl.sub.2 to give the polysulfides of the formula (I) where K.sub.1.sup.+ and K.sub.2.sup.+ are each H.sup.+ and n is 2, 3, 4, 5 and/or 6, and at least one of: b1) contacting the resulting polysulfides of the formula (I) with water or a mixture of water and an inert organic medium, and heating to a temperature of >60 C., and b2) contacting the resulting polysulfides of the formula (I) with a solution of metal salts of the cations K.sub.1.sup.+ and K.sub.2.sup.+ at a temperatures >60 C., and treating the polysulfides at temperatures of 80 C.-120 C.

12. A rubber mixture comprising: at least one rubber, at least one filler, and the polysulfides as claimed in claim 1.

13. The rubber mixture as claimed in claim 12, wherein: the at least one filler comprises one or more silica-based fillers, and a proportion by weight of silica-based fillers is at least 10% of a total filler content, and the rubber mixture additionally contains a sulfur-containing alkoxysilane.

14. The rubber mixture as claimed in claim 12, wherein the rubber mixture additionally comprises one or more crosslinkers.

15. The rubber mixture as claimed in claim 12, wherein the rubber mixture comprises 0.1 to 15 phr of the polysulfides.

16. The rubber mixture as claimed in claim 12, wherein the at least one rubber comprises at least one SBR rubber and at least one BR rubber in a weight ratio of SBA rubber:BR rubber of 60:40 to 90:10.

17. The rubber mixture as claimed in claim 16, wherein: the at least one rubber further comprises at least one NR rubber, and a weight ratio of SBR rubber to BR rubber to NR rubber is 60 to 85:10 to 35:5 to 20; the filler comprises one or more silica-based fillers, and the proportion by weight of silica-based fillers is at least 80% of a total filler content; the rubber mixture additionally contains a sulfur-containing alkoxysilane, and the rubber mixture comprises 0.7 to 15 phr of the polysulfides.

18. A process for producing the rubber mixtures as claimed in claim 12, the process comprising mixing the at least one rubber, the at least one filler, and the polysulfides by a multistage mixing process in which the polysulfides are added in a first stage of the mixing process, and one or more crosslinkers are added in a later mixing stage subsequent to the first stage.

19. A process for producing vulcanizates, the process comprising vulcanizing the rubber mixture as claimed in claim 10 at blend temperatures of 100 to 200 C.

20. A vulcanizate obtained by the process of claim 19.

Description

EXAMPLE 1

[0104] ##STR00005##

[0105] Apparatus: 2000 ml four-neck flask with thermometer, dropping funnel with pressure equalizer, reflux condenser with gas outlet attachment (bubble counter) and hose, stirrer, gas inlet tube

[0106] Initial charge: 118.0 g=0.75 mol of mercaptobenzoic acid (Merck, 98%), 900 ml of toluene (p.A., from Merck, dried over molecular sieve)

[0107] Feed: 51.15 g=0.375 mol of disulfur dichloride (99%, from Merck)

[0108] The nitrogen-purged apparatus is initially charged with dried toluene and mercaptobenzoic acid. The disulfur dichloride is then added dropwise to the suspension present under a nitrogen flow at a temperature of 0-5 C. within about 1 h. The metering rate should be adjusted such that a temperature of 5 C. is not exceeded. After the reaction has ended, stirring of the mixture continues under a nitrogen flow at room temperature overnight. Subsequently, the reaction solution is filtered with suction through a D4 frit and washed through 2 with about 200 ml of dried toluene. The product is dried at room temperature (about 25 C.) in a vacuum drying cabinet.

[0109] Yield: 144.6 g (104.1%) of a polysulfide mixture of the idealized formula

##STR00006##

[0110] Elemental analysis: C: 45.0% H: 3.0% O: 16.7% S: 33.6% Cl: 1.4%

[0111] The melting range and the end of the melting range were determined visually with the Bchi Melting Point B-545 melting point apparatus. The heating rate was 1 C./min, starting from a temperature of 290 C.

TABLE-US-00001 Melting range: 296-299 C. Melting range (end): 299 C.

[0112] An x-ray diffraction analysis was conducted.

TABLE-US-00002 Diffractometer: PANalytical X'Pert PRO Geometry: transmission Primary monochromator focusing x-ray mirror Detector: PixCEL 2D Radiation: Cu K-alpha Tube voltage: 40 kV Tube current: 40 mA Measurement range: 2-80 in 2theta Step width in 2theta: 0.013 Step time: 100 s Evaluation software: PANalytical HighScorePlus v.3

[0113] The x-ray diffractogram (Cu K-alpha radiation) shows the following three largest signals:

TABLE-US-00003 Diffraction angle 2theta (): 26.6 Relative intensity: 100% Diffraction angle 2theta (): 14.6 Relative intensity: 75% Diffraction angle 2theta (): 21.1 Relative intensity: 54%

[0114] The x-ray diffractogram (Cu K-alpha radiation) does not show any signal at a diffraction angle 2theta () of 27.2.

[0115] It is obvious from the dominant signal at a diffraction angle 2theta () of 26.6 that the product is of the alpha crystal polymorph.

[0116] The product has a very intense odor.

[0117] The mixture of 10 g of polysulfide mixture with 100 ml of water, after being refluxed for 30 min and cooled down to 25 C., exhibited a pH of 1.2 and a conductivity of 14 mS/cm.

EXAMPLE 2

[0118] ##STR00007##

[0119] Apparatus: 2000 ml four-neck flask with thermometer, dropping funnel with pressure equalizer, reflux condenser with gas outlet attachment (bubble counter) and hose, stirrer, gas inlet tube

[0120] Initial charge: 118.0 g=0.75 mol of mercaptobenzoic acid (Merck, 98%), 900 ml of toluene (p.A., from Merck, dried over molecular sieve)

[0121] Feed: 51.15 g=0.375 mol of disulfur dichloride (99%, from Merck)

[0122] The nitrogen-purged apparatus is initially charged with dried toluene and mercaptobenzoic acid. The disulfur dichloride is then added dropwise to the suspension present under a nitrogen flow at a temperature of 20-25 C. within about 30 min. The metering rate should be adjusted such that a temperature of 25 C. is not exceeded. After the reaction has ended, stirring of the mixture continues under a nitrogen flow at 20-25 C. for 1 h. Then 20 ml of demineralized water and 180 ml of toluene are added and the mixture is heated to reflux under a nitrogen flow for 2 h. Subsequently, about 200 ml are distilled off under standard pressure with a nitrogen flow.

[0123] The mixture is cooled to room temperature. Subsequently, the reaction solution is filtered with suction through a D4 frit and washed through 2 with about 200 ml of dried toluene. The product is dried at room temperature (about 25 C.) in a vacuum drying cabinet.

[0124] Yield: 139.5 g (100.4%) of a polysulfide mixture of the idealized formula

##STR00008##

[0125] Elemental analysis: C: 45.2% H: 2.7% O: 18.1% S: 33.6% Cl: 0.05%

[0126] The melting range and the end of the melting range were determined visually with the Bchi Melting Point B-545 melting point apparatus. The heating rate was 1 C./min, starting from a temperature of 290 C.

TABLE-US-00004 Melting range: 302-305 C. Melting range (end): 305 C.

[0127] The x-ray diffractogram (Cu K-alpha radiation) shows the following three largest signals:

TABLE-US-00005 Diffraction angle 2theta (): 27.2 Relative intensity: 100% Diffraction angle 2theta (): 21.0 Relative intensity: 30% Diffraction angle 2thela (): 13.5 Relative intensity: 24%

[0128] It is obvious from the dominant signal at a diffraction angle 2theta () of 27.2 that the product is of the beta crystal polymorph.

[0129] The product was analyzed by RP-HPLC and time-of-flight mass spectrometry (TOF MS).

[0130] The percentages with regard to the compounds of the formula (I) with K.sub.1.sup.+ and K.sub.2.sup.+=H.sup.+ are taken directly from the area percentages of HPLC measurement with a UV detector:

[0131] <1% compound with n=2, 1% compound with n=3, 97% compound with n=4, 1% compound with n=5, <1% compound with n=6.

[0132] HPLC instrument: Agilent 1100 Series with degasser, binary pump, column oven, variable wavelength detector and autosampler

TABLE-US-00006 Stationary phase: Inertsil ODS-3, particle diameter 3 m Column length: 150 mm Internal diameter of column: 2.1 mm Mobile phase A: 100% water + 25 mmol ammonium acetate B: 95% methanol: 5% water + 25 mmol ammonium acetate

TABLE-US-00007 Elution program: Time (min) Eluent A (% by vol.) Eluent B (% by vol.) 0 80 20 5 80 20 30 1 99 60 1 99 62 80 20

TABLE-US-00008 Column temperature: 40 C. Flow rate: 0.3 ml/min Run time: 72 min Injection volume: 5 l Wavelength of UV detector: 225 nm

[0133] A 50 mg sample of product to be analyzed was weighed into a 50 ml volumetric flask, dissolved by adding about 10 ml of tetrahydrofuran and making the mixture up to the calibration mark with tetrahydrofuran.

[0134] The product has a slight intrinsic odor.

[0135] The mixture of 10 g of polysulfide mixture with 100 ml of water, after being refluxed for 30 min and cooled down to 25 C., exhibited a pH of 3.4 and a conductivity of 0.2 mS/cm.

EXAMPLE 3

[0136] ##STR00009##

[0137] Apparatus: 2000 ml four-neck flask with thermometer, dropping funnel with pressure equalizer, reflux condenser with gas outlet attachment (bubble counter) and hose, stirrer, gas inlet tube

[0138] Initial charge: 236.0 g=1.5 mol of mercaptobenzoic acid (Merck, 98%), 1000 ml of toluene (p.A., from Merck, dried over molecular sieve)

[0139] Feed: 102.3 g=0.75 mol of disulfur dichloride (99%, from Merck)

[0140] The nitrogen-purged apparatus is initially charged with dried toluene and mercaptobenzoic acid. The disulfur dichloride is then added dropwise to the suspension present under a nitrogen flow at a temperature of 20-25 C. within about 30 min. The metering rate should be adjusted such that a temperature of 25 C. is not exceeded. After the reaction has ended, stirring of the mixture continues under a nitrogen flow at 20-25 C. for 1 h. Then 100 ml of demineralized water are added and the mixture is heated to reflux under a nitrogen flow for 4 h.

[0141] The mixture is cooled to room temperature. Subsequently, the reaction solution is filtered with suction through a D4 frit and washed through 2 with about 300 ml of toluene. The product is dried at about 50 C. in a vacuum drying cabinet.

[0142] Yield: 279 g (100.4%) of a polysulfide mixture of the idealized formula

##STR00010##

[0143] Elemental analysis: C: 45.3% H: 2.9% O: 17.4% S: 34.5% Cl: 0.02%

[0144] The melting range and the end of the melting range were determined visually with the Bchi Melting Point B-545 melting point apparatus. The heating rate was 1 C./min, starting from a temperature of 290 C.

TABLE-US-00009 Melting range: 302-305 C. Melting range (end): 305 C.

[0145] The x-ray diffractogram (Cu K-alpha radiation) shows the following three largest signals:

TABLE-US-00010 Diffraction angle 2theta (): 27.2 Relative intensity: 100% Diffraction angle 2theta (): 21.0 Relative intensity: 22% Diffraction angle 2theta (): 13.5 Relative intensify: 21%

[0146] It is obvious from the dominant signal at a diffraction angle 2theta () of 27.2 that the product is of the beta crystal polymorph.

[0147] The product was analyzed by RP-HPLC and time-of-flight mass spectrometry (TOF MS).

[0148] The percentages with regard to the compounds of the formula (I) with K.sub.1.sup.+ and K.sub.2.sup.+=H.sup.+ are taken directly from the area percentages of HPLC measurement with a UV detector:

[0149] <1% compound with n=2, <1% compound with n=3, 97% compound with n=4, 1% compound with n=5, <1% compound with n=6.

[0150] The product has a slight intrinsic odor.

[0151] The mixture of 10 g of polysulfide mixture with 100 ml of water, after being refluxed for 30 min and cooled down to 25 C., exhibited a pH of 3.5 and a conductivity of 0.1 mS/cm.

EXAMPLE 4

[0152] ##STR00011##

[0153] Apparatus: 2000 ml four-neck flask with thermometer, dropping funnel with pressure equalizer, reflux condenser with gas outlet attachment (bubble counter) and hose, stirrer, pH electrode

[0154] Initial charge: 74.1 g of example 1 polysulfide mixture, 700 ml of water

[0155] Feed: 35.9 g=0.2 mol of ZnSO.sub.4xH.sub.2O (from Aldrich, 100%) dissolved in 300 ml of water

[0156] Feed: 160.0 g=0.4 mol of NaOH solution (10%)

[0157] The nitrogen-purged apparatus is initially charged with the water and the polysulfide mixture from example 1 and heated to 95-100 C. The ZnSO.sub.4 solution is then added dropwise to the mixture present under a nitrogen flow at a temperature of 95-100 C. within about 1 h. The mixture is stirred for a further 1 h. This is followed by the metered addition of the NaOH solution at 95-100 C. within about 1 h. The mixture is stirred at about 100 C. for a further 1 h. After cooling, the product is filtered with suction through a D4 frit and washed with 500 ml portions of water until the conductivity of the washing water is <0.3 mS/cm. The product is dried at 50 C. in a vacuum drying cabinet.

[0158] Yield: 79.3 g (91.4%) of a polysulfide mixture of the idealized formula

##STR00012##

[0159] Elemental analysis: C: 37.8% H: 2.1% O: 16.0% S: 29.7% Zn: 16% Cl: 110 ppm

[0160] The product has a slight intrinsic odor.

[0161] The mixture of 10 g of polysulfide mixture with 100 ml of water, after being refluxed for 30 min and cooled down to 25 C., exhibited a pH of 5.9 and a conductivity of 0.6 mS/cm.

EXAMPLE 5

[0162] ##STR00013##

[0163] Apparatus: 2000 ml four-neck flask with thermometer, dropping funnel with pressure equalizer, reflux condenser with gas outlet attachment (bubble counter) and hose, stirrer, pH electrode

[0164] Initial charge: 74.1 g of example 1 polysulfide mixture, 700 ml of water

[0165] Feed: 35.9 g=0.2 mol of ZnSO.sub.4xH.sub.2O (from Aldrich, 100%) dissolved in 300 ml of water

[0166] Feed: 160.0 g=0.4 mol of NaOH solution (10%)

[0167] The nitrogen-purged apparatus is initially charged with the water and the polysulfide mixture from example 1 at 20-25 C. The ZnSO.sub.4 solution is then added dropwise to the mixture present under a nitrogen flow at a temperature of 20-25 C. within about 1 h. The mixture is stirred for a further 1 h. This is followed by the metered addition of the NaOH solution at 20-25 C. within about 1 h. Then the mixture is heated to gentle reflux and stirred at about 100 C. for a further 1 h. After cooling, the product is filtered with suction through a D4 frit and washed with 500 ml portions of water until the conductivity of the washing water is <0.3 mS/cm. The product is dried at 50 C. in a vacuum drying cabinet.

[0168] Yield: 79.3 g (91.0%) of a polysulfide mixture of the idealized formula

##STR00014##

[0169] Elemental analysis: C: 38.5% H: 2.2% O: 16.0% S: 29.7% Zn: 14% Cl: 80 ppm

[0170] The product has a slight intrinsic odor.

[0171] The mixture of 10 g of polysulfide mixture with 100 ml of water, after being refluxed for 30 min and cooled down to 25 C., exhibited a pH of 6.0 and a conductivity of 0.4 mS/cm.

Production of Rubber Mixtures and Rubber Vulcanizates

[0172] The rubber formulations listed in table 1 were each mixed by the multistage process described below.

1st Mixing Stage:

[0173] BUNA CB 24 and BUNA VSL 5025-2 were initially charged in an internal mixer and mixed for about 30 seconds [0174] Addition of two thirds of VULKASIL S, two thirds of SI 69, two thirds of the total amount of inventive polysulfides of the formula (I), mix for about 60 seconds [0175] Addition of one third of VULKASIL S, one third of SI 69, one third of the total amount of inventive polysulfides of the formula (I) and TUDALEN 1849-1, mix for about 60 seconds

[0176] Addition of CORAX N 339, EDENOR C 18 98-100, VULKANOX 4020/LG, VULKANOX HS/LG, ZINKWEISS ROTSIEGEL and ANTILUX 654, mix for about 60 seconds. The mixing was effected at a temperature of 150 C.

2nd Mixing Stage:

[0177] On completion of the first mixing stage, the mix was taken up by a downstream roller system and formed to a sheet and stored at room temperature for 24 hours. The processing temperatures here were below 60 C.

3rd Mixing Stage:

[0178] The third mixing stage is a further mastication at 150 C. in a kneader.

4th Mixing Stage:

[0179] Addition of the additives MAHLSCHWEFEL 90/95 CHANCEL, VULKACIT CZ/C, VULKACIT D/C on a roller at temperatures below 80 C.

[0180] The rubber mixtures were subsequently fully vulcanized at 170 C. The properties of the rubber preparations produced and the vulcanizates thereof are reported in table 2.

TABLE-US-00011 TABLE 1 Rubber formulation Rubber Rubber Rubber Rubber Rubber formulation formulation formulation formulation formulation Reference 1 2 3 4 5 BUNA CB 24 30 30 30 30 30 30 BUNA VSL 5025-2 96 96 96 96 96 96 CORAX N 339 6.4 6.4 6.4 6.4 6.4 6.4 VULKASIL S 80 80 80 80 80 80 TUDALEN 1849-1 8 8 8 8 8 8 EDENOR C 18 98-100 1 1 1 1 1 1 VULKANOX 4020/LG 1 1 1 1 1 1 VULKANOX HS/LG 1 1 1 1 1 1 ZINKWEISS 2.5 2.5 2.5 2.5 2.5 2.5 ROTSIEGEL ANTILUX 654 1.5 1.5 1.5 1.5 1.5 1.5 SI 69 6.4 6.4 6.4 6.4 6.4 6.4 VULKACIT D/C 2 2 2 2 2 2 VULKACIT CZ/C 1.5 1.5 1.5 1.5 1.5 1.5 MAHLSCHWEFEL 1.5 1.5 1.5 1.5 1.5 1.5 90/95 CHANCEL Example 1 compound 1 Example 2 compound 1 Example 3 compound 1 Example 4 compound 1 Example 5 compound 1

TABLE-US-00012 Amounts stated in phr (parts by weight per 100 parts of rubber) Trade name Details Manufacturer/distributor BUNA CB 24 BR Lanxess Deutschland GmbH BUNA VSL 5025-2 SBR Lanxess Deutschland GmbH CORAX N 339 carbon black Degussa-Evonik GmbH VULKASIL S silica Lanxess Deutschland GmbH TUDALEN 1849-1 mineral oil Hansen&Rosenthal KG EDENOR C stearic acid Cognis Deutschland 18 98-100 GmbH VULKANOX N-1,3-dimethylbutyl- Lanxess Deutschland 4020/LG N-phenyl-p- GmbH phenylenediamine VULKANOX 2,2,4-trimethyl- Lanxess Deutschland HS/LG 1,2-dihydroquinoline GmbH polymerized ZINKWEISS zinc oxide Grillo Zinkoxid GmbH ROTSIEGEL ANTILUX 654 light stabilizer wax RheinChemie Rheinau GmbH SI 69 bis(triethoxysilylpropyl) Evonik Industries tetrasulfide VULKACIT D/C 1,3-diphenylguanidine Lanxess Deutschland GmbH VULKACIT CZ/C N-cyclonexyl-2- Lanxess Deutschland benzothiazole- GmbH sulfenamide MAHLSCHWEFEL sulfur Solvay Deutschland 90/95 CHANCEL GmbH

TABLE-US-00013 TABLE 2 Summary of results Rubber Rubber Rubber Rubber formulation formulation formulation formulation Parameter Unit DIN Reference 1 2 3 5 Mooney [ME] 53523 95 92 84 91 89 viscosity (ML 1 + 4) Mooney scorch sec ASTM D 1253 1228 1020 972 960 at 130 C. (t5) 5289-95 Vulcanization at sec 53529 1417 1315 1475 1844 1580 170 C. (t95) Shore A [Shore A] 53505 66 73 67 69 68 hardness at 23 C. 300 modulus MPa 53504 15 18 16 17 17 Elongation at % 53504 349 308 361 302 314 break Tensile strength MPa 53504 19 18 20 18 18 Abrasion mm.sup.3 53516 74 93 83 77 72 Rolling 0.133 0.154 0.093 0.094 0.090 resistance (tan (60 C.))

[0181] The tested vulcanizates comprising the inventive rubber mixtures 2, 3 and 5, compared to the reference, show elevated hardness values and 300 modulus values, improved rolling resistance and lower Mooney viscosity. Compared to rubber mixture 1 comprising a compound of the formula (I) having a relatively high chlorine content and relatively high residual acidity, the inventive rubber mixtures 2, 3 and 5 show a distinct improvement in terms of abrasion and rolling resistance, with a maintained or reduced Mooney viscosity.