IN-CHAIN PHOSPHINE- AND PHOSPHONIUM- CONTAINING DIENE-POLYMERS

Abstract

In-chain phosphine- and/or phosphonium-containing diene-polymers, the preparation and use thereof, as well as vulcanizable rubber compounds comprising such polymers, and their use for the production of moldings in particular in the production of tires.

Claims

1. A polymer comprisinq: repeating monomeric units of at least one diene and at least one phosphine or phosphonium containing monomeric unit according to the formulae B1, B2, and/or B3: ##STR00005## where per formula B1: n=0 or 1, and when n=0, then R.sup.1, R.sup.2 are the same or different and are each an H, a linear and branched alkyl, aryl especially phenyl and alkylated phenyl, benzyl, cycloalkoxy, aryloxy, alkaryloxy, aralkyl or aralkoxy radical which may contain one or more heteratoms, X is the polymerized form of allyl, styryl, methyl styryl, p-tert-butylstyryl, 1,3-pentadienyl, 2-methylene buta-1,3-diene, 1,3-butadienyl, 2,3-dimethylbutadienyl, 1-phenyl-1,3-butadienyl, 1,3-hexadienyl, or mixtures thereof, and when n=1, then R.sup.1, R.sup.2 are as above, R.sup.3 is H, linear and branched alkyl, aryl, benzyl, polybutadienyl, polyisoprenyl, polyacryl, X is the polymerized form of a allyl, styryl, methyl styryl, p-tert-butylstyryl, 1,3-pentadienyl, 2-methylene buta-1,3-diene, 1,3-butadienyl, 2,3-dimethylbutadienyl, 1-phenyl-1,3-butadienyl, 1,3-hexadienyl and mixtures thereof, and A.sup. is F.sup., Cl.sup., Br.sup., J.sup., OH.sup., SH.sup., BF.sub.4.sup., SO.sub.4.sup.2, HSO.sub.4.sup., HSO.sub.3.sup., NO.sub.2.sup., NO.sub.3.sup., carboxylate RC(O)O.sup., dialkyl phosphate (RO).sub.2P(O)O.sup., dialkyl dithiophosphate (RO).sub.2P(S)S.sup., dialkyl phosphorothioate (RO).sub.2P(S)O.sup., where per formula B2: n=0 or 1, and R.sup.1 is are the same or different and are each an H, a linear and branched alkyl, aryl, benzyl, cycloalkoxy, aryloxy, alkaryloxy, aralkyl or aralkoxy radical which may contain one or more heteratoms, R.sup.3 is H, linear and branched alkyl, aryl, benzyl, polybutadienyl, polyisoprenyl, polyacryl X is the polymerized form of a allyl, styryl, methyl styryl, p-tert-butylstyryl, 1,3-pentadienyl, 2-methylene buta-1,3-diene, 1,3-butadienyl, 2,3-dimethylbutadienyl, 1-phenyl-1,3-butadienyl, 1,3-hexadienyl and mixtures thereof, and A.sup. is F.sup., Cl.sup., Br.sup., J.sup., OH.sup., SH.sup., BF.sub.4.sup., SO.sub.4.sup.2, HSO.sub.4.sup., HSO.sub.3.sup., NO.sub.2.sup., NO.sub.3.sup., carboxylate RC(O)O.sup., dialkyl phosphate (RO).sub.2P(O)O.sup., dialkyl dithiophosphate (RO).sub.2P(S)S.sup., dialkyl phosphorothioate (RO).sub.2P(S)O.sup., where per formula B3: n=0 or 1, and R.sup.3 is H, linear and branched alkyl, aryl, benzyl, polybutadienyl, polyisoprenyl, polyacryl X is the polymerized form of a allyl, styryl, methyl styryl, p-tert-butylstyryl, 1,3-pentadienyl, 2-methylene buta-1,3-diene, 1,3-butadienyl, 2,3-dimethylbutadienyl, 1-phenyl-1,3-butadienyl, 1,3-hexadienyl and mixtures thereof, and A.sup. is F.sup., Cl.sup., Br.sup., J.sup., OH.sup., SH.sup., BF.sub.4.sup., SO.sub.4.sup.2, HSO.sub.4.sup., HSO.sub.3.sup., NO.sub.2.sup., NO.sub.3.sup., carboxylate RC(O)O.sup., dialkyl phosphate (RO).sub.2P(O)O.sup., dialkyl dithiophosphate (RO).sub.2P(S)S.sup., dialkyl phosphorothioate (RO).sub.2P(S)O.sup.. wherein said polymer is further end chain functionalized and thereby comprises one or more end-chain functional groups which contain one or more heteroatoms selected from the group consisting of O, N, S, Si, and Sn.

2. The polymer according to claim 1, further comprising repeating monomeric units of a vinylaromatic compound.

3. The polymer according to claim 1, wherein the diene is butadiene or isoprene, preferably butadiene.

4. The polymer according to claim 1, wherein at least one X comprises the polymerized form of styryl and butadiene.

5. The polymer according to claim 1, wherein the polymer has a number-average molecular weight, M.sub.n, from 10 000 to 2 000 000 g/mol.

6. The polymer according to claim 1, wherein the polymer has a glass transition temperature of from 110 C. to +20 C.

7. The polymers according to claim 1, wherein said end chain functional groups are selected from the group consisting of silane-containing carbinol groups of the formula (I) ##STR00006## or their metal salts according to the formula (II): ##STR00007## where R.sup.4, R.sup.5, R.sup.6, R.sup.7 are identical or different and are H, alkyl moieties, cycloalkyl moieties, aryl moieties, alkaryl moieties and aralkyl moieties, where these can comprise heteroatoms, B is a divalent organic moiety which can comprise, in addition to C and H, heteroatoms, n is an integer from 1 to 4, M is a metal or semimetal of valency from 1 to 4.

8. A vulcanizable rubber composition, comprising: a polymer according to claim 1, a rubber, optionally a filler, optionally a coupling agent, and at least one crosslinking system comprising at least one crosslinker and optionally one or more crosslinking accelerators.

9. The vulcanizable rubber composition according to claim 8, wherein said filler is a silica based filler, and said coupling agent is a sulphur-containing-silane comprising a sulfane moiety and having a molar ratio of sulfur to silicium of less than 1.35:1.

10. The vulcanizable rubber composition according to claim 9, wherein the coupling agent is selected from the group consisting of bis[3-(triethoxysilyl)propyl]monosulfane, bis[3(triethoxysilyl)propyl]disulfane, bis[3-(triethoxysilyl)propyl]trisulfane, bis[3(triethoxysilyl)propyl]tetrasulfane), and mixtures thereof.

11. A process for producing vulcanizates, comprising: vulcanizing the vulcanizable rubber composition according to claim 8.

12. The process according to claim 11, wherein said vulcanizing step is performed at a temperature in the range from 100 C. to 200 C.

13. Vulcanizates obtained by the process according to claim 11.

14. The vulcanizates according to claim 13, wherein said vulcanizates are shaped in the form of shaped bodies.

15. A process for forming a polymer, comprising the steps of: polymerizing at least one diene and at least one phosphine or phosphonium containing monomer according to the formulae A1, A2, and/or A3 ##STR00008## where per formula A1, n=0 or 1, and when n=0, then R.sup.1, R.sup.2 are the same or different and are each an H, a linear and branched alkyl, aryl, benzyl, cycloalkoxy, aryloxy, alkaryloxy, aralkyl or aralkoxy radical which may contain one or more heteratoms, X is allyl, styryl, methyl styryl, p-tert-butylstyryl, 1,3-pentadienyl, 2-methylene buta-1,3-diene, 1,3-butadienyl, 2,3-dimethylbutadienyl, 1-phenyl-1,3-butadienyl, 1,3-hexadienyl, or mixtures thereof, and when n=1, then R.sup.1, R.sup.2 are as above, R.sup.3 is H, linear and branched alkyl, aryl, benzyl, polybutadienyl, polyisoprenyl, polyacryl, X is a allyl, styryl, methyl styryl, p-tert-butylstyryl, 1,3-pentadienyl, 2-methylene buta-1,3-diene, 1,3-butadienyl, 2,3-dimethylbutadienyl, 1-phenyl-1,3-butadienyl, 1,3-hexadienyl and mixtures thereof, and A.sup. is F.sup., Cl.sup., Br.sup., J.sup., OH.sup., SH.sup., BF.sub.4.sup., SO.sub.4.sup.2, HSO.sub.4.sup., HSO.sub.3.sup., NO.sub.2.sup., NO.sub.3.sup., carboxylate RC(O)O.sup., dialkyl phosphate (RO).sub.2P(O)O.sup., dialkyl dithiophosphate (RO).sub.2P(S)S.sup., dialkyl phosphorothioate (RO).sub.2P(S)O.sup., and where per formula A2: n=0 or 1, and R.sup.1 is are the same or different and are each an H, a linear and branched alkyl, aryl, benzyl, cycloalkoxy, aryloxy, alkaryloxy, aralkyl or aralkoxy radical which may contain one or more heteratoms, R.sup.3 is H, linear and branched alkyl, aryl, benzyl, polybutadienyl, polyisoprenyl, polyacryl X is a allyl, styryl, methyl styryl, p-tert-butylstyryl, 1,3-pentadienyl, 2-methylene buta-1,3-diene, 1,3-butadienyl, 2,3-dimethylbutadienyl, 1-phenyl-1,3-butadienyl, 1,3-hexadienyl and mixtures thereof, A.sup. is F.sup., Cl.sup., Br.sup., J.sup., OH.sup., SH.sup., BF.sub.4.sup., SO.sub.4.sup.2, HSO.sub.4.sup., HSO.sub.3.sup., NO.sub.2.sup., NO.sub.3.sup., carboxylate RC(O)O.sup., dialkyl phosphate (RO).sub.2P(O)O.sup., dialkyl dithiophosphate (RO).sub.2P(S)S.sup., dialkyl phosphorothioate (RO).sub.2P(S)O.sup., and where for formula A3: n=0 or 1, and R.sup.3 is H, linear and branched alkyl, aryl, benzyl, polybutadienyl, polyisoprenyl, polyacryl, X is a allyl, styryl, methyl styryl, p-tert-butylstyryl, 1,3-pentadienyl, 2-methylene buta-1,3-diene, 1,3-butadienyl, 2,3-dimethylbutadienyl, 1-phenyl-1,3-butadienyl, 1,3-hexadienyl and mixtures thereof, and A.sup. is F.sup., Cl.sup., Br.sup., J.sup., OH.sup., SH.sup., BF.sub.4.sup., SO.sub.4.sup.2, HSO.sub.4.sup., HSO.sub.3.sup., NO.sub.2.sup., NO.sub.3.sup., carboxylate RC(O)O.sup., dialkyl phosphate (RO).sub.2P(O)O.sup., dialkyl dithiophosphate (RO).sub.2P(S)S.sup., dialkyl phosphorothioate (RO).sub.2P(S)O.sup., wherein the polymer is reacted with one or more end-chain functionalizing reagents whereby one or more functional groups are bonded to the polymer at its terminal chain ends, wherein said end-chain functionalizing reagents contain one or more heteroatoms selected from the group consisting of O, N, S, Si, and Sn.

16. The process according to claim 15, wherein said polymerization is performed in the presence of a further monomer.

17. The process according to claim 15, wherein the diene is butadiene or isoprene.

18. The process according to claim 15, wherein the at least one monomer according to the formula A1, A2, and A3 is styryl(diphenyl)phosphine and/or its corresponding alkyl-phosphonium salt.

19. The process according to claim 15, wherein said end-chain functionalizing reagents are 1-oxa-2-silacycloalkanes.

20. The product obtained according the process according to claim 15.

Description

EXAMPLES

[0136] The following properties were determined in accordance with the stated standards:

DIN 52523/52524 Mooney viscosity M.sub.L(1+4).sub.100 C.
DIN 53505: Shore A hardness
DIN 53512: rebound resilience at 60 C.
DIN 53504: tensile test
DIN53513: dynamic damping via Eplexor equipmentEplexor equipment (Eplexor 500 N) from Gabo-Testanlagen GmbH, Ahlden, Germany was used to determine dynamic properties (temperature dependency of storage modulus E in the temperature range from 60 C. to 0 C. and also tan at 60 C.). The values were determined in accordance with DIN53513 at 10 Hz on Ares strips in the temperature range from 100 C. to +100 C. at a heating rate of 1 K/min.

[0137] The method was used to obtain the following variables, the terminology here being in accordance with ASTM 5992-96: tan (60 C.): loss factor (E/E) at 60 C., tan (60 C.) is a measure of hysteresis loss from the tire under operating conditions. As tan (60 C.) decreases, the rolling resistance of the tire decreases.

[0138] DIN 53513-1990: Elastic propertiesAn MTS elastomer test system (MTS Flex Test) from MTS was used to determine the elastic properties. The measurements were carried out in accordance with DIN53513-1990 on cylindrical samples (2 samples each 206 mm) with a total 2 mm compression at a temperature of 60 C. and a measurement frequency of 1 Hz in the range of amplitude sweep from 0.1 to 40%. The method was used to obtain the following variables, the terminology here being in accordance with ASTM 5992-96: G* (15%): dynamic modulus at 15% amplitude sweep; tan (max: maximum loss factor (G/G) of entire measuring range at 60 C. The relative proportions of 1,4-trans-, 1,2-vinyl- and 1,4-cis-butadiene, and styrene units were determined on the basis of the measurement of the relative absorptions of 1,4-trans-, 1,2-vinyl- and 1,4-cis-butadiene, and styrene bands in the IR spectrum of polymer films. The method is calibrated with rubber samples having a microstructure known accurately from NMR studies. The figures in % by weight are based only on the incorporated units in the rubber and together add up to 100% by weight.

[0139] The amount of phosphine or phosphonium containing monomeric unit of the polymer is measured according to inductively coupled plasma optical emission spectrometry (ICP-OES) and reported in percent of the theoretically amount of Phosphorus that could be fully incorporated into the polymer.

Comparative Polymer SBR 1: Synthesis of styrene-butadiene Copolymer, Unfunctionalized

[0140] An inertized 20 L reactor was charged with 8500 g of hexane, 1125 g of 1,3-butadiene, 375 g of styrene, 36 mmol of ditetrahydrofurylpropane (DTHFP) and 18 mmol of butyllithium, and the contents were heated to 70 C. Polymerization was effected while stirring for 60 minutes. Subsequently, 18 mmol of 1-octanol were added to cap the anionic ends of the polymer chains, the rubber solution was discharged and stabilized by addition of 0.5 phr of Irganox 1520 (2,4-bis(octylthiomethyl)-6-methylphenol). The rubber was isolated by precipitation in ethanol and was dried at 65 C. under reduced pressure.

ML(1+4100) C=88.1 MU

[0141] Microstructure: 53.0 wt-% vinyl butadiene; 11.8 wt-% 1,4 cis butadiene; 11.3 wt-% 1,4 trans butadiene; 24.0 wt-% styrene

Example Polymer SBR 2: Synthesis of Styrene-Butadiene-SDPP Terpolymer

[0142] An inertized 2 L reactor was charged with 850 g of hexane, 112.5 g of 1,3-butadiene, 37.5 g of styrene, 1.5 g of styryl(diphenyl)phosphine, 5.32 mmol of 2-(2-ethoxyethoxy)-2-methylpropane (BEE) and 1.40 mmol of butyllithium, and the contents were heated to 70 C. Polymerization was effected while stirring for 60 minutes. Subsequently, 1.4 mmol of 1-octanol were added to cap the anionic ends of the polymer chains, the rubber solution was discharged and stabilized by addition of 0.5 phr of Irganox 1520 (2,4-bis(octylthiomethyl)-6-methylphenol). The rubber was isolated by precipitation in ethanol and was dried at 65 C. under reduced pressure.

ML(1+4)100 C.=85.6 MU

[0143] Microstructure: 59.6 wt-% vinyl butadiene; 8.6 wt-% 1,4 cis butadiene; 8.8 wt-% 1,4 trans butadiene; 23.0 wt-% styrene

Phosphorus (ICP-OES): 84%.

[0144] Example polymer SBR 3 was prepared analogously to SBR 2 with the 3 g of styryl(diphenyl)phosphine:

ML(1+4100) C=84.4 MU

[0145] Microstructure: 55.7 wt-% vinyl butadiene; 9.0 wt-% 1,4 cis butadiene; 10.0 wt-% 1,4 trans butadiene; 25.3 wt-% styrene

Phosphorus (ICP-OES): 96%.

Example Polymer SBR 4: Synthesis of Omeqa-Functionalized, Styrene-Butadiene-SDPP Terpolymer

[0146] An inertized 2 L reactor was charged with 850 g of hexane, 112.5 g of 1,3-butadiene, 37.5 g of styrene, 1.5 g of styryl(diphenyl)phosphine, 7.22 mmol of 2-(2-ethoxyethoxy)-2-methylpropane (BEE) and 1.90 mmol of butyllithium, and the contents were heated to 70 C. Polymerization was effected while stirring for 60 minutes. Subsequently, 1.90 mmol of 2,2,4-trimethyl-[1,4,2]oxazasilane were added to cap the anionic ends of the polymer chains, the rubber solution was discharged and stabilized by addition of 0.5 phr of Irganox 1520 (2,4-bis(octylthiomethyl)-6-methylphenol). The rubber was isolated by precipitation in ethanol and was dried at 65 C. under reduced pressure.

ML(1+4100) C=51.9 MU

[0147] Microstructure: 59.9 wt-% vinyl butadiene; 8.4 wt-% 1,4 cis butadiene; 8.4 wt-% 1,4 trans butadiene; 23.3 wt-% styrene

Phosphorus (ICP-OES): 87%.

Example Polymer SBR 5: Synthesis of Alpha-Functionalized, Styrene-Butadiene-SDPP Terpolymer

[0148] An inertized 2 L reactor was charged with 850 g of hexane, 112.5 g of 1,3-butadiene, 37.5 g of styrene, 1.5 g of styryl(diphenyl)phosphine, 7.22 mmol of 2-(2-ethoxyethoxy)-2-methylpropane (BEE), 1.90 mmol of 4-methyl piperidine and 1.90 mmol of butyllithium, and the contents were heated to 70 C. Polymerization was effected while stirring for 60 minutes. Subsequently, 1.90 mmol of n-octanol were added to cap the anionic ends of the polymer chains, the rubber solution was discharged and stabilized by addition of 0.5 phr of Irganox 1520 (2,4-bis(octylthiomethyl)-6-methylphenol). The rubber was isolated by precipitation in ethanol and was dried at 65 C. under reduced pressure.

ML(1+4100) C=40.9 MU

[0149] Microstructure: 60.3 wt-% vinyl butadiene; 9.8 wt-% 1,4 cis butadiene; 11.6 wt-% 1,4 trans butadiene; 18.3 wt-% styrene

Phosphorus (ICP-OES): 91%.

Example Polymer SBR 6: Synthesis of Alpha-Functionalized and Omeqa-Functionalized, Styrene-Butadiene-SDPP Terpolymer

[0150] An inertized 2 L reactor was charged with 850 g of hexane, 112.5 g of 1,3-butadiene, 37.5 g of styrene, 1.5 g of styryl(diphenyl)phosphine, 7.22 mmol of 2-(2-ethoxyethoxy)-2-methylpropane (BEE), 1.90 mmol of 4-methyl piperidine and 1.90 mmol of butyllithium, and the contents were heated to 70 C. Polymerization was effected while stirring for 60 minutes. Subsequently, 1.90 mmol of 2,2,4-trimethyl-[1,4,2]oxazasilane were added to cap the anionic ends of the polymer chains, the rubber solution was discharged and stabilized by addition of 0.5 phr of Irganox 1520 (2,4-bis(octylthiomethyl)-6-methylphenol). The rubber was isolated by precipitation in ethanol and was dried at 65 C. under reduced pressure.

ML(1+4100) C=42.5 MU

[0151] Microstructure: 57.3 wt-% vinyl butadiene; 9.6 wt-% 1,4 cis butadiene; 11.2 wt-% 1,4 trans butadiene; 21.9 wt-% styrene

Phosphorus (ICP-OES): 82%.

[0152] Following substances were used in the compounds:

TABLE-US-00001 Tradename Producer BUNA CB 24 (Nd-Polybutadiene) Lanxess Deutschland GmbH Zeosil 1165MP (silica) Solvay GmbH VIVATEC 500 (TDAE oil) Hansen und Rosenthal KG EDENOR C 18 98-100 (stearic acid) Caldic Deutschland GmbH VULKANOX 4020 LG (stabilizer) Lanxess Deutschland GmbH RHENOGRAN ZNO-80 (ZnO) Lanxess Deutschland GmbH VULKANOX HS/LG (stabilizer) Lanxess Deutschland GmbH RHENOGRAN CBS-80 (accelerator) Lanxess Deutschland GmbH RHENOGRAN IS 90-65 (sulfur) Lanxess Deutschland GmbH ANTILUX 654 (ozone protection) Lanxess Deutschland GmbH SI 266 (silane) Evonik Industries AG

[0153] Compound Recipe for a Silica Tread Compound

TABLE-US-00002 Example 1 reference Example 2 Example 3 Example 4 Example 5 Example 6 BUNA CB 24 30 30 30 30 30 30 ZEOSIL 90 90 90 90 90 90 1165MP VIVATEC 500 33 33 33 33 33 33 AFLUX 37 2 2 2 2 2 2 EDENOR C18- 1 1 1 1 1 1 98 MY VULKANOX 1 1 1 1 1 1 4020/LG VULKANOX 1 1 1 1 1 1 HS/LG SBR 1 70 SBR 2 70 SBR 3 70 SBR 4 70 SBR 5 70 SBR 6 70 ANTILUX 654 1 1 1 1 1 1 SI 266 6.6 6.6 6.6 6.6 6.6 6.6 RHENOGRAN 2 2 2 2 2 2 CBS-80 RHENOGRAN 3.4 3.4 3.4 3.4 3.4 3.4 IS 90-65 RHENOGRAN 1.49 1.49 1.49 1.49 1.49 1.49 DPG-80 RHENOGRAN 3.8 3.8 3.8 3.8 3.8 3.8 ZNO-80

[0154] Mixing Protocol

TABLE-US-00003 Step 1 mixer Step 2 0 sec addition of polymers 30 sec addition of of filler, silane, stearic acid, oil and 90 sec addition of of filler, silane, stearic acid, oil 150 sec addition of ZnO 210 sec heating to silanization temperature (150 C.) 390 sec Stop milling at 40 C., nip of 4 mm Step 3 Cut sheet threetimes left and right, continue with three endwise passes storage for 24 hours at 23 C. Step 4 mixer Step 5 0 sec addition of rubber sheet and heating to 150 C. 210 sec Stop Milling at 40 C., nip of 4 mm addition of sulphur and accelerator, cut sheet threetimes left and right, continue with three endwise passes

[0155] Comparative Results for the Compounded Materials and Vulcanizates

TABLE-US-00004 Example 1 reference Example 2 Example 3 Example 4 Example 5 Example 6 Compound Mooney Visc. ML (1 + 4) 100 C. ME 76.4 82.63 86.57 70.22 72.67 74.34 Dynamic damping, 10 Hz. Temp. Sweep tan d (0 C.) 0.477 0.696 0.727 0.783 0.61 0.641 tan d (60 C.) 0.13 0.119 0.106 0.13 0.13 0.116 Rebound @ 60 C. % 51 52.5 54.5 53.5 55.5 54 Rebound @ 23 C. % 28.33 19.87 19.93 18.87 28.73 26.33 Re @ 60 C. Re @ 23 C. % 22.67 32.63 34.57 34.63 26.77 27.67 Hardness @ 23 C. Shore A 61 62 65 60 56 58 MTS 1 Hz. 60 C., Ampl. Sweep tan d (max.) 0.204 0.183 0.163 0.2 0.195 0.187 G (0.5%) MPa 2.33 1.83 1.78 1.81 1.67 1.6 G (15%) MPa 1.18 1.15 1.23 1.16 1.07 1.05 G (0.5%) G (15%) 1.15 0.68 0.55 0.65 0.6 0.55 Tensile strain @ 23 C. S100 MPa 1.9 2.7 3.5 2.6 2.1 2.3 S300 MPa 10.8 15.7 14.9 12.5 13.8

[0156] Various tests were run on the reference compound with SBR1 and the innovative example compounds including SBR 2, SBR 3, SBR 4, SBR 5, SBR 6 and on the corresponding vulcanizates to ascertain the final properties. The compound recipe is understood as a standard composition for a silica tire tread, but the application of the innovative rubbers are not limited to these types of compounds. The innovative examples do not strongly differ from the compound Mooney viscosity obtained for the reference material which in generally points on a similar processability behavior and allows for direct comparison of performance relevant measurements

[0157] Dynamic damping measurements (temperature sweep mode) allows for the prediction of wet grip, which is generally indicated by a high tan delta at 0 C. and for rolling resistance which is described by low tan delta at 60 C. The incorporation of SDPP to the SSBR strongly increases tan delta 0 C. and reduces in turn the tan delta 60 C. as can be seen from the comparison of the reference compound example 1 to the innovative example 2 and 3. Further, it can be seen that combinations of SDPP incorporation with end-group functionalization, both at the alpha or omega position or both, allow for additional improvement of the respective performance indicator (example 4, 5, 6).

[0158] MTS amplitude sweep measurements at 60 C. allow for additional investigation of rolling resistance represented by the tan delta maximum value. These measurements confirm the observation of the temperature sweep measured. Further, MTS amplitude sweep measurements allow for characterization of the filler distribution, represented by a lower difference of G at low and G at high amplitude (G(0.5%)-G(15%); so-called Payne effect). A strong decrease in Payne was observed for the SDPP-incorporated SSBR compounds example 2 and 3. Further, the combination of SDPP containing SSBR with end-functionalization technologies allow for additional reduction of filler-filler interactions due to increased rubber-filler interactions.

[0159] A third measurement which is widely known to describe rolling resistance of a tire is the rebound measured at 60 C. These measurements further confirm the tan delta measurements from amplitude and temperature sweep measurements. A low value for the rebound measured at 23 C., in contrast, is a measurement describing wet grip. This means in turn that that difference of the Rebound 60 C. and the Rebound 23 C. should be ideally high since this confirms an improved balance between rolling resistance and wet grip. Comparing the reference compound to the all innovative compounds 2-6, it can be seen that the innovative, SDPP containing SSBRs result in a significant inclination of these two rebound values.

[0160] Tensile measurements at 23 C. were performed on these vulcanizates. By applying the innovative, SDPP containing SSBRs to the compound, the stress at 300% of deformation is strongly increased. In case of example 3, the elongation at break was below the 300%. As can be seen from the S100%, for this compound the modulus was already significantly increased at low deformations. The combinations of the SDPP technology with end-functionalization chemistry resulted in a minor decrease for the modulus at 300% of deformation, but are still significantly higher than for the reference vulcanizate example 1.

[0161] The data presented confirm that the application of an SDPP containing SSBR results in significant improvement of tire performance and further confirm the these technology can be combined with alpha-functionalization or end-functionalization or alpha- and end-functionalization.

[0162] The block styrene content was measured by NMR in 1,1,2,2-tetrachloroethane at 80 C. on a Bruker DPX 400. The solvent signal was set on 5.93 ppm.

[0163] The total amount of styrene was integrated from 6.2 ppm to 7.4 ppm (5 protons). The block styrene content (block being defined as n>6 styryl units) were determined from the chemical shift range of 6.2 ppm to 6.7 ppm (representing the 2 ortho-protons, the meta and para protons overlap with the overall protons in the range of 6.7 ppm to 7.4 ppm). From the comparison of SBR 1 (reference SSBR without SDPP) and SBR 2 (SSBR containing 1 phr of SDDP), it can be seen that the content of block-styryl moieties are not affected by the presence of SDPP.

TABLE-US-00005 thereof blockstyrene cis-/trans- vinyl- Total (n > 6 repeating butadiene butadiene styrene units) Sample (wt-%) (wt-%) (wt-%) (wt-%) Example 20.4 54 25.6 0.9 polymer SBR 2 Comparative 20.4 54.5 25.1 0.8 polymer SBR 1

[0164] From the above, it can be seen that the polymer according to the invention clearly is a statistical polymer and no block copolymer as the amount of blockstyrene lies below 1 wt. %.

[0165] With this regard, according to the present invention, statistical polymers are such polymers which only comprises up to 5 wt. %, preferably up to 2.5 wt. %, more preferably up to 1.5 wt. % of an overall monomer content as block-monomer, such as styrene content as block styrene. Such block-monomer content can be determined in the polymer via NMR using the method as described above.