CARBOXYTERMINATED DIENE RUBBERS

Abstract

The invention relates to carboxyterminated diene rubbers, their production and use.

Claims

1. A carboxyterminated polymer according to general formula (I), ##STR00013## wherein the polymer contains at least one carbon-carbon double bond; R.sub.2, R.sub.3 are identical or different and represent saturated or unsaturated organic radicals which, in addition to C and H, may contain one or more heteroatoms independently selected from the group consisting of O, N, S, and Si; and R.sub.1, R.sub.4 are identical or different and represent saturated or unsaturated divalent organic radicals which, in addition to C and H, may contain one or more heteroatoms independently selected from the group consisting of O, N, S, and Si.

2. The carboxyterminated polymer according to claim 1, which is obtained by a polymerization reaction comprising polymerizing one or more dienes selected from the group consisting of 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-phenyl-1,3-butadiene and 1,3-hexadiene.

3. The carboxyterminated polymer according to claim 2, wherein the polymer is obtainable by homo- or copolymerization of 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-phenyl-1,3-butadiene or 1,3-hexadiene; or copolymerization of (i) 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-phenyl-1,3-butadiene, 1,3-hexadiene, and combinations thereof with (ii) a vinyl aromatic monomer selected from the group consisting of styrene, o-, m- and/or p-methylstyrene, p-tert-butylstyrene, methylstyrene, vinylnaphthalene, divinylbenzene, trivinylbenzene, divinylnaphthalene, and combinations thereof.

4. The carboxyterminated polymer according to claim 3, which is obtained by copolymerization of 1,3-butadiene with styrene; or isoprene with styrene.

5. (canceled)

6. The carboxyterminated polymer according to claim 1, wherein R.sub.1 is selected from the group consisting of (i) —C.sub.1-C.sub.6-alkylene-, saturated or unsaturated, unsubstituted, mono- or polysubstituted; (ii) —C.sub.1-C.sub.6-heteroalkylene-, saturated or unsaturated, unsubstituted, mono- or polysubstituted; and (iii) 6-14-membered arylene, unsubstituted, mono- or polysubstituted; R.sub.2 is selected from the group consisting of (i) —C.sub.1-C.sub.24-alkyl, saturated or unsaturated, unsubstituted, mono- or polysubstituted; or (ii) —C.sub.1-C.sub.24-heteroalkyl, saturated or unsaturated, unsubstituted, mono- or polysubstituted; (iii) 6-24-membered aryl, unsubstituted, mono- or polysubstituted, wherein said 6-24-membered aryl is optionally connected through —C.sub.1-C.sub.6-alkylene- or —C.sub.1-C.sub.6-heteroalkylene-, in each case saturated or unsaturated, unsubstituted, mono- or polysubstituted; (iv) 5-24-membered heteroaryl, unsubstituted, mono- or polysubstituted; wherein said 5-24-membered heteroaryl is optionally connected through —C.sub.1-C.sub.6-alkylene- or —C.sub.1-C.sub.6-heteroalkylene-, in each case saturated or unsaturated, unsubstituted, mono- or polysubstituted; (v) 3-24-membered cycloalkyl, saturated or unsaturated, unsubstituted, mono- or polysubstituted; wherein said 3-24-membered cycloalkyl is optionally connected through —C.sub.1-C.sub.6-alkylene- or —C.sub.1-C.sub.6-heteroalkylene-, in each case saturated or unsaturated, unsubstituted, mono- or polysubstituted; and (vi) 3-24-membered heterocycloalkyl, saturated or unsaturated, unsubstituted, mono- or polysubstituted; wherein said 3-24-membered heterocycloalkyl is optionally connected through —C.sub.1-C.sub.6-alkylene- or —C.sub.1-C.sub.6-heteroalkylene-, in each case saturated or unsaturated, unsubstituted, mono- or polysubstituted; R.sub.3 is selected from the group consisting of (i) —C.sub.1-C.sub.24-alkyl, saturated or unsaturated, unsubstituted, mono- or polysubstituted; (ii) —C.sub.1-C.sub.24-heteroalkyl, saturated or unsaturated, unsubstituted, mono- or polysubstituted; (iii) 6-24-membered aryl, unsubstituted, mono- or polysubstituted, wherein said 6-24-membered aryl is optionally connected through —C.sub.1-C.sub.6-alkylene- or —C.sub.1-C.sub.6-heteroalkylene-, in each case saturated or unsaturated, unsubstituted, mono- or polysubstituted; (iv) 5-24-membered heteroaryl, unsubstituted, mono- or polysubstituted; wherein said 5-24-membered heteroaryl is optionally connected through —C.sub.1-C.sub.6-alkylene- or —C.sub.1-C.sub.6-heteroalkylene-, in each case saturated or unsaturated, unsubstituted, mono- or polysubstituted; (v) 3-24-membered cycloalkyl, saturated or unsaturated, unsubstituted, mono- or polysubstituted; wherein said 3-24-membered cycloalkyl is optionally connected through —C.sub.1-C.sub.6-alkylene- or —C.sub.1-C.sub.6-heteroalkylene-, in each case saturated or unsaturated, unsubstituted, mono- or polysubstituted; and (vi) 3-24-membered heterocycloalkyl, saturated or unsaturated, unsubstituted, mono- or polysubstituted; wherein said 3-24-membered heterocycloalkyl is optionally connected through —C.sub.1-C.sub.6-alkylene- or —C.sub.1-C.sub.6-heteroalkylene-, in each case saturated or unsaturated, unsubstituted, mono- or polysubstituted; R.sub.4 is selected from the group consisting of (i) —C.sub.1-C.sub.6-alkylene-, saturated or unsaturated, unsubstituted, mono- or polysubstituted; (ii) —C.sub.1-C.sub.6-heteroalkylene-, saturated or unsaturated, unsubstituted, mono- or polysubstituted; and (iii) 6-14-membered arylene, unsubstituted, mono- or polysubstituted; wherein “mono- or polysubstituted” means substituted with one substituent in the case of “monosubstituted” or with more than one substituents in the case of “polysubstituted”, wherein the substituents independently of one another are selected from the group consisting of —F, —Cl, —Br, —I, —CN, ═O, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, —CF.sub.2C.sub.1, —CFCl.sub.2, —C.sub.1-C.sub.18-alkyl, which is saturated or unsaturated, unsubstituted, and —C.sub.1-C.sub.18-heteroalkyl, which is saturated or unsaturated, unsubstituted.

7. The carboxyterminated polymer according to claim 6, wherein R.sub.1 is (i) —C.sub.1-C.sub.6-alkylene-, saturated or unsaturated, unsubstituted; R.sub.2 is (i) —C.sub.1-C.sub.6-alkyl, saturated or unsaturated, unsubstituted; R.sub.3 is (i) —C.sub.1-C.sub.6-alkyl, saturated or unsaturated, unsubstituted; R.sub.4 is (i) —C.sub.1-C.sub.6-alkylene-, saturated or unsaturated, unsubstituted, mono- or polysubstituted; wherein substituents for “mono- or polysubstituted” are independently of one another selected from —F, —Cl, —Br, —I, —CN, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, —CF.sub.2C.sub.1, —CFCl.sub.2, —C.sub.1-C.sub.8-alkyl, which is saturated or unsaturated, unsubstituted, and —C.sub.1-C.sub.8-heteroalkyl, which is saturated or unsaturated, unsubstituted.

8. The carboxyterminated polymer according to claim 1, wherein the polymer is obtained by copolymerization of 1,3-butadiene with styrene; R.sub.1 is —C.sub.1-C.sub.3-alkylene-, saturated or unsaturated, unsubstituted; R.sub.2 is —C.sub.1-C.sub.2-alkyl, saturated or unsaturated, unsubstituted; R.sub.3 is —C.sub.1-C.sub.2-alkyl, saturated or unsaturated, unsubstituted; and R.sub.4 is selected from —CH.sub.2—CHC.sub.kH.sub.2k+1—, wherein k is an integer of from 8 to 16; —CH.sub.2CH((CH.sub.2).sub.1-5Si(OC.sub.1-C.sub.4-alkyl).sub.3); —CH═CC.sub.1-C.sub.4-alkyl-, and —(CH.sub.2).sub.2-4—.

9. The carboxyterminated polymer according to claim 1, which is present as a carboxylate according to general formula (II), ##STR00014## wherein polymer, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as defined in claim 1; n is an integer from 1 to 4; and M is a metal or semi-metal of valency 1 to 4.

10. A method for the preparation of a carboxyterminated polymer according to general formula (I), ##STR00015## or general formula (II), ##STR00016## the method comprising: (a) providing a polymer containing at least one carbon-carbon double bond; (b) providing a cyclic urea derivative of the general formula (III) ##STR00017## (c) providing a cyclic carboxylic anhydride of the general formula (IV) ##STR00018## (d) adding the cyclic urea derivative of general formula (III) to the polymer as a first functionalization reagent to form a functionalized polymer intermediate; and (e) subsequently adding the cyclic carboxylic anhydride of the general formula (IV) to the functionalized polymer intermediate as a second functionalization reagent to form the carboxyterminated polymer according to general formula (I) or the carboxylate according to general formula (II); wherein R.sub.2, R.sub.3 are identical or different and represent saturated or unsaturated organic radicals which, in addition to C and H, may contain one or more heteroatoms independently selected from the group consisting of O, N, S and Si; and R.sub.1, R.sub.4 are identical or different and represent saturated or unsaturated divalent organic radicals which, in addition to C and H, may contain one or more heteroatoms independently selected from the group consisting of O, N, S and Si.

11. The method according to claim 10, wherein step (a) is performed by an anionic solution polymerization, or a polymerization using a coordination catalyst.

12. The method according to claim 10, wherein step (a) is performed in the presence of a solvent selected from the group consisting of cyclohexane, methylcyclopentane, n-hexane, and mixtures thereof; and an initiator.

13. The method according to claim 10, wherein step (a) is performed within a period of 10 minutes to 8 hours.

14. The method according to claim 10, which further comprises adding (f) a coupling reagent before, together with or after addition of the cyclic urea derivative of general formula (III); and/or (g) an antioxidant after the cyclic urea derivative of the general formula (III) and the cyclic carboxylic anhydride of general formula (IV) have been added; and/or (h) an extender oil; and/or (i) a filler; and/or (j) rubbers and/or rubber additives.

15. (canceled)

16. The method according to claim 10, wherein the polymer is obtainable by a polymerization reaction comprising the polymerization of one or more dienes wherein the one or more dienes are selected from the group consisting of 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-phenyl-1,3-butadiene or 1,3-hexadiene.

17. The method according to claim 10, wherein the polymer is obtainable by a copolymerization of (i) 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-phenyl-1,3-butadiene, 1,3-hexadiene or a combination thereof with (ii) a vinylaromatic monomer selected from the group consisting of styrene, o-, m- and/or p-methylstyrene, p-tert-butylstyrene, methylstyrene, vinylnaphthalene, divinylbenzene, trivinylbenzene, divinylnaphthalene or a combination thereof.

18. The method according to claim 10, wherein the polymer is obtainable by a copolymerization of 1,3-butadiene with styrene or by a copolymerization of isoprene with styrene.

19. The method according to claim 10, wherein R.sub.1 is selected from the group consisting of (i) a —C.sub.1-C.sub.6-alkylene- that is saturated or unsaturated and that is unsubstituted, mono- or polysubstituted; (ii) a —C.sub.1-C.sub.6-heteroalkylene- that is saturated or unsaturated and that is unsubstituted, mono- or polysubstituted; and (iii) a 6 to 14-membered arylene that is unsubstituted, mono- or polysubstituted; R.sub.2 is selected from the group consisting of (i) a —C.sub.1-C.sub.24-alkyl that is saturated or unsaturated and that is unsubstituted, mono- or polysubstituted; or (ii) a —C.sub.1-C.sub.24-heteroalkyl that is saturated or unsaturated and that is unsubstituted, mono- or polysubstituted; (iii) a 6 to 24-membered aryl that is unsubstituted, mono- or polysubstituted, wherein said 6 to 24-membered aryl is optionally connected through —C.sub.1-C.sub.6-alkylene- or —C.sub.1-C.sub.6-heteroalkylene-, which in each case is saturated or unsaturated and which is unsubstituted, mono- or polysubstituted; (iv) a 5 to 24-membered heteroaryl that is unsubstituted, mono- or polysubstituted, wherein said 5 to 24-membered heteroaryl is optionally connected through a —C.sub.1-C.sub.6-alkylene- or a —C.sub.1-C.sub.6-heteroalkylene-, which in each case is saturated or unsaturated and which is unsubstituted, mono- or polysubstituted; (v) a 3 to 24-membered cycloalkyl that is saturated or unsaturated and unsubstituted, mono- or polysubstituted wherein said 3 to 24-membered cycloalkyl is optionally connected through a —C.sub.1-C.sub.6-alkylene- or a —C.sub.1-C.sub.6-heteroalkylene-, which in each case is saturated or unsaturated and which is unsubstituted, mono- or polysubstituted; and (vi) a 3 to 24-membered heterocycloalkyl that is saturated or unsaturated and that is unsubstituted, mono- or polysubstituted, wherein said 3 to 24-membered heterocycloalkyl is optionally connected through a —C.sub.1-C.sub.6-alkylene- or a —C.sub.1-C.sub.6-heteroalkylene-, which in each case is saturated or unsaturated and which is unsubstituted, mono- or polysubstituted; R.sub.3 is selected from the group consisting of (i) a —C.sub.1-C.sub.24-alkyl that is saturated or unsaturated and that is unsubstituted, mono- or polysubstituted; (ii) a —C.sub.1-C.sub.24-heteroalkyl that is saturated or unsaturated and that is unsubstituted, mono- or polysubstituted; (iii) a 6 to 24-membered aryl that is unsubstituted, mono- or polysubstituted, wherein said 6 to 24-membered aryl is optionally connected through a —C.sub.1-C.sub.6-alkylene- or a —C.sub.1-C.sub.6-heteroalkylene-, which in each case is saturated or unsaturated, and which is unsubstituted, mono- or polysubstituted; (iv) a 5 to 24-membered heteroaryl that is unsubstituted, mono- or polysubstituted, wherein said 5 to 24-membered heteroaryl is optionally connected through a —C.sub.1-C.sub.6-alkylene- or a —C.sub.1-C.sub.6-heteroalkylene-, which in each case is saturated or unsaturated and which is unsubstituted, mono- or polysubstituted; (v) a 3 to 24-membered cycloalkyl that is saturated or unsaturated and that is unsubstituted, mono- or polysubstituted; wherein said 3 to 24-membered cycloalkyl is optionally connected through a —C.sub.1-C.sub.6-alkylene- or a —C.sub.1-C.sub.6-heteroalkylene-, which in each case is saturated or unsaturated and which is unsubstituted, mono- or polysubstituted; and (vi) a 3 to 24-membered heterocycloalkyl, that is saturated or unsaturated and that is unsubstituted, mono- or polysubstituted, wherein said 3 to 24-membered heterocycloalkyl is optionally connected through a —C.sub.1-C.sub.6-alkylene- or a —C.sub.1-C.sub.6-heteroalkylene-, which in each case is saturated or unsaturated and which is unsubstituted, mono- or polysubstituted; R.sub.4 is selected from the group consisting of (i) a —C.sub.1-C.sub.6-alkylene-, that is saturated or unsaturated and that is unsubstituted, mono- or polysubstituted; (ii) a —C.sub.1-C.sub.6-heteroalkylene-, that is saturated or unsaturated and that is unsubstituted, mono- or polysubstituted; and (iii) a 6 to 14-membered arylene, that is unsubstituted, mono- or polysubstituted; wherein “mono- or polysubstituted” means substituted with one substitutent in case of “monosubstituted” and with one or more substituents in case of “polysubstituted” and wherein the substituents are selected independently from the group consisting of —F, —Cl, —Br, —I, —CN, ═O, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, —CF.sub.2C.sub.1, —CFCl.sub.2, a —C.sub.1-C.sub.18-alkyl that is saturated or unsaturated and that is unsubstituted, and a —C.sub.1-C.sub.8-heteroalkyl that is saturated or unsaturated and that is unsubstituted.

20. The method according to claim 10, wherein R.sub.1 is (i) a —C.sub.1-C.sub.6-alkylene- that is saturated or unsaturated, and that is unsubstituted; R.sub.2 is (i) a —C.sub.1-C.sub.6-alkyl that is saturated or unsaturated and that is unsubstituted; R.sub.3 is (i) a —C.sub.1-C.sub.6-alkyl that is saturated or unsaturated and that is unsubstituted; R.sub.4 is (i) a —C.sub.1-C.sub.6-alkylene- that is saturated or unsaturated and that is unsubstituted, mono- or polysubstituted; wherein “mono- or polysubstituted” means substituted with one substitutent in case of “monosubstituted” or with more than one substituents in case of “polysubstituted” and where the substituents are selected independently from the group consisting of —F, —Cl, —Br, —I, —CN, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, —CF.sub.2C.sub.1, —CFCl.sub.2, a —C.sub.1-C.sub.8-alkyl that is saturated or unsaturated and that is unsubstituted, and a —C.sub.1-C.sub.8-heteroalkyl that is saturated or unsaturated and that is unsubstituted.

21. The method according to claim 10, wherein the polymer is obtainable by a copolymerization of 1,3-butadiene with styrene; R.sub.1 is a —C.sub.1-C.sub.3-alkylene- that is saturated or unsaturated and that is unsubstituted; R.sub.2 is a —C.sub.1-C.sub.2-alkyl that is saturated or unsaturated and that is unsubstituted; R.sub.3 is a —C.sub.1-C.sub.2-alkyl that is saturated or unsaturated and that is unsubstituted; and R.sub.4 is selected from —CH.sub.2—CHC.sub.kH.sub.2k+1—, —CH.sub.2CH((CH.sub.2).sub.1-5Si(OC.sub.1-C.sub.4-alkyl).sub.3)-, —CH═C—(C.sub.1-C.sub.4-alkyl)-, and —(CH.sub.2).sub.2-4—, wherein k is an integer of from 8 to 16.

22. A molded article prepared by vulcanizing a vulcanizable composition comprising the carboxy-terminated polymer of claim 1.

23. A tire prepared by vulcanizing a vulcanizable composition comprising the carboxy-terminated polymer of claim 1.

Description

EXAMPLES

[0145] The number-average molecular weight Mn, the polydispersity Mw/Mn and the degree of coupling of the styrene-butadiene rubbers were determined using GPC (PS calibration).

[0146] The Mooney viscosity ML(1+4)100° C. was measured according to DIN 52523/52524.

[0147] The vinyl and styrene content was determined by FTIR spectroscopy on rubber films.

[0148] The glass transition temperature Tg was determined using DSC from the 2nd heating curve at a heating rate of 20 K/min.

[0149] The loss factors tan δ were measured at 0° C. and tan δ at 60° C. to determine the temperature-dependent dynamic-mechanical properties. An Eplexor device (Eplexor 500 N) from Gabo was used for this purpose. The measurements were carried out in accordance with DIN 53513 at 10 Hz on Ares strips in the temperature range from −100° C. to 100° C. The Eplexor 500 N was used for this purpose. To determine the strain-dependent dynamic-mechanical properties, ΔG′ was determined as the difference between the shear modulus at 0.5% strain and the shear modulus at 15% strain as well as the maximum loss factor tan δmax. These measurements were determined according to DIN53513-1990 on an MTS elastomer test system on cylinder specimens (20×6 mm) with 2 mm compression at a temperature of 60° C. and a measuring frequency of 10 Hz in the strain range from 0.1% to 40%.

[0150] The rebound elasticity was determined at 60° C. according to DIN 53512.

[0151] Styrene-butadiene copolymers

Example 1: Synthesis of Styrene-Butadiene Copolymer, Non-Functionalized (Comparative Example

[0152] An inert 20 L reactor was filled with 8.5 kg hexane, 6.1 mmol 2,2-bis(2-tetrahydrofuryl)-propane and 11.1 mmol n-butyllithium (as a 23% solution by weight in hexane) and heated to 41° C. The heating circuit was then closed and 1185 g of 1,3-butadiene and 315 g of styrene were added simultaneously.

[0153] It was polymerized under stirring for 40 minutes whereas the reactor contents reached a peak temperature of 66° C. Subsequently, 11.1 mmol n-octanol was added to stop the anionic polymer chain ends. The rubber solution was drained, stabilized by adding 3 g Irganox® 1520 (2,4-bis(octylthiomethyl)-6-methylphenol) and the solvent removed by stripping with steam. The rubber crumbs were dried at 65° C. for 16 h in a vacuum drying oven.

[0154] The number-average molecular weight Mn, the molecular weight distribution Mw/Mn, the degree of coupling (all from the GPC measurement with PS calibration), the Mooney viscosity ML1+4@100° C., the vinyl and styrene content (from the FTIR measurement, data in % by weight, based on the total polymer), as well as the glass transition temperature Tg (from the DSC measurement) were determined on the dried rubber crumbs. The values are listed in Table 1.

Example 2: Functionalization of Styrene-Butadiene Copolymer by Reaction with 1,3-Dimethyl-2-Imidazolidinone (Comparative Example)

[0155] The procedure was the same as in example 1. Instead of n-octanol, however, the amount of the functionalization reagent 1,3-dimethyl-2-imidazolidinone (1) equimolar to n-butyllithium was added and the reactor content then stirred for a further 5 minutes. The rubber solution was then drained, stabilized by adding 3 g Irganox® 1520 (2,4-bis(octylthiomethyl)-6-methylphenol) and the solvent removed by stripping with steam. The rubber crumbs were dried at 65° C. for 16 h in a vacuum drying oven.

Example 3: Functionalization of Styrene-Butadiene Copolymer by Reaction with Citraconic Anhydride (Comparative Example)

[0156] The procedure was the same as in example 2. As functionalization reagent, the equimolar amount to n-butyl-lithium of citraconic anhydride (26) was added.

Example 4: Functionalization of Styrene-Butadiene Copolymer by Successive Reaction with 1,3-dimethyl-2-imidazolidinone and Citraconic Anhydride (Example According to Invention)

[0157] The procedure was the same as in example 2. For functionalization, the amount of 1,3-dimethyl-2-imidazolidinone (1) equimolar to n-butyl-lithium was added first. It was stirred for 5 minutes, then the equimolar amount to n-butyllithium of citraconic anhydride (26) was added.

Example 5: Functionalization of Styrene-Butadiene Copolymer by Reaction with Tetrapropenyl Succinic Anhydride (Comparative Example)

[0158] The procedure was the same as in example 2. As functionalization reagent, the amount of tetrapropenyl succinic anhydride (20) equimolar to n-butyl lithium was added.

Example 6: Functionalization of Styrene-Butadiene Copolymer by Successive Reaction with 1,3-dimethyl-2-imidazolidinone and Tetrapropenyl Succinic Anhydride (Example According to Invention)

[0159] The procedure was the same as in example 2. For functionalization, the amount of 1,3-dimethyl-2-imidazolidinone (1) equimolar to n-butyl-lithium was added first. It was stirred for 5 minutes, then the equimolar amount to n-butyllithium of tetrapropenyl succinic anhydride (20) was added.

Example 7: Functionalization of Styrene-Butadiene Copolymer by Reaction with Glutaric Anhydride (Comparative Example)

[0160] The procedure was the same as in example 2. The amount of glutaric anhydride (29) equimolar to n-butyl-lithium was added as functionalization reagent.

Example 8: Functionalization of Styrene-Butadiene Copolymer by Successive Reaction with 1,3-dimethyl-2-imidazolidinone and Glutaric Anhydride (Example According to Invention)

[0161] The procedure was the same as in example 2. For functionalization, the amount of 1,3-dimethyl-2-imidazolidinone (1) equimolar to n-butyl-lithium was added first. It was stirred for 5 minutes and then the equimolar amount to n-butyllithium of glutaric anhydride (29) was added.

Example 9: Functionalization of Styrene-Butadiene Copolymer by Reaction with 3-(trimethoxysilyl)propyl Succinic Anhydride (Comparative Example)

[0162] The procedure was the same as in example 2. As functionalization reagent, the amount of 3-(trimethoxysilyl)propyl succinic anhydride (22) equimolar to n-butyl lithium was added.

Example 10: Functionalization of Styrene-Butadiene Copolymer by Successive Reaction with 1,3-dimethyl-2-imidazolidinone and 3-(trimethoxysilyl)-propyl Succinic Anhydride (Example According to Invention)

[0163] The procedure was the same as in example 2. For functionalization, the amount of 1,3-dimethyl-2-imidazolidinone (1) equimolar to n-butyl-lithium was added first. It was stirred for 5 minutes, then the equimolar amount to n-butyllithium of 3-(trimethoxysilyl)propyl succinic anhydride (22) was added.

[0164] The polymer properties of the styrene-butadiene copolymers from examples 1-10 are summarized in Table 1. Table 1 shows that the carboxy-terminated polymers of examples 4, 6, 8 and 10, prepared by successive addition of the two functionalization reagents according to formula (III) and (IV), according to the invention, have significantly reduced coupling degrees compared to the polymers of examples 3, 5, 7 and 9, prepared by addition of functionalization reagents according to formula (IV) without prior addition of a functionalization reagent according to formula (III). At similar molecular weight, polydispersity and coupling levels as the polymers of comparison examples 1 and 2, the carboxy terminated polymers of examples 4, 6, 8 and 10 according to invention exhibit significantly higher Mooney viscosities. This can be explained by the association formation of the carboxyterminated polymers via the carboxy or carboxylate end groups in the undiluted state (relevant for Mooney measurement), which is no longer effective in diluted solution (relevant for GPC measurement).

[0165] Rubber Compounds

[0166] Tire tread rubber compounds containing the styrene-butadiene copolymers of examples 1-10 were produced. The components are listed in Table 2. The components (without sulfur and accelerator) were mixed in a 1.5 L kneader. The components sulfur and accelerator were mixed in on a roller at 40° C. The individual steps in the preparation of the mixture are listed in Table 3.

TABLE-US-00001 TABLE 1 Properties of the styrene-butadiene copolymers according to Examples 1-10 functionalization functionalization reagent reagent Degree of vinyl- styrene- S-SBR from according to according to M.sub.n coupling ML1 + 4 content content Tg Example formula (III) formula (IV) [kg/mol] M.sub.w/M.sub.n [%] [MU] [wt.-%] [wt.-%] [° C.] 1 — — 275 1.15 0 54 49.8 21.2 −24.7 (comparative) 2 (1) — 261 1.19 1 57 50.9 21.1 −23.6 (comparative) 3 — (26) 254 1.52 42 81 50.5 20.9 −23.5 (comparative) 4 (1) (26) 200 1.28 1 76 50.1 21.0 −25.1 (inventive) 5 — (20) 241 1.66 51 75 50.0 21.0 −24.3 (comparative) 6 (1) (20) 238 1.29 4 67 49.9 21.4 −24.2 (inventive) 7 — (29) 248 1.64 51 72 50.5 20.3 −25.2 (comparative) 8 (1) (29) 264 1.20 3 83 51.3 21.3 −22.8 (inventive) 9 — (22) 365 3.23 72 80 49.6 21.0 −25.4 (comparative) 10 (1) (22) 239 1.95 17 72 49.3 21.0 −26.0 (inventive)

TABLE-US-00002 TABLE 2 Components of tire tread rubber compounds (Specifications in phr: parts by weight per 100 parts by weight rubber) Styrene-butadiene copolymer 70 High-cis polybutadiene (BUNA CB 24 from Arlanxeo 30 Deutschland GmbH) Silica (Ultrasil ® 7000) 90 Carbon black (Vulcan ® J/N 375) 7 TDAE oil (Vivatec 500) 36.3 Processing aid (Aflux 37) 3 Stearic acid (Edenor C 18 98-100) 1 Antioxidant (Vulkanox ® 4020/LG der Lanxess 2 Deutschland GmbH) Antioxidant (Vulkanox ® HS/LG der Lanxess 2 Deutschland GmbH) Zink oxide (Zinkweiβ Rotsiegel) 3 Light protection wax (Antilux 654) 2 Silane (Si 69 ® from Evonik) 7.2 Diphenylguanidine (Rhenogran DPG-80) 2.75 Sulfenamide (Vulkacit ® NZ/EGC from Lanxess 1.6 Deutschland GmbH) Sulphur (Mahlschwefel 90/95 Chancel) 1.6 Sulfonamide (Vulkalent ® E/C) 0.2

TABLE-US-00003 TABLE 3 Preparation Step 1: 0 seconds Addition of polymers Mixing in a 30 seconds Addition of ⅔ silica, ⅔ silane, stearic 1.5 litre acid, wax, antioxidant, carbon black kneader 90 seconds Addition of residual silica and silane 150 seconds Addition of zinc oxide 240 seconds Heat up to 150° C., hold at temperature for 3 min 420 seconds Ejection Step 2: Cut the sheet three times left and Mixing on right followed by 3 revolutions at the roller 40° C. and a nip of 4 mm Step 3: 24 hours storage at 24° C. Step 4: 0 seconds Addition of the compound from step 3 Mixing in a 30 seconds Heat up to 150° C., hold 1.5 litre at temperature for 3 min kneader 210 seconds Ejection Step 5: Addition of sulphur and accelerator, Mixing on cut the sheet three times the roller left and right followed by 3 rounds at 40° C. and a nip of 4 mm

[0167] The rubber compounds were vulcanized at 160° C. for 20 minutes. The physical properties of the corresponding vulcanizates 11-20 are listed in Table 4. The vulcanizate properties of the vulcanized rubber compound from comparison example 11 with the non-functionalized styrene-butadiene copolymer as the compound component are given an index of 100. All values greater than 100 in Table 4 indicate a corresponding percentage improvement of the respective test property.

TABLE-US-00004 TABLE 4 Properties of vulcanizates contains S-SBR Tan Tan rebound Vulcanizate from δ at δ at Tan δ elasticity Example Example 0° C. 60° C. Maximum ΔG′ at 60° C. 11 1 100 100 100 100 100 (compar- ative) 12 2 109 106 107 121 101 (compar- ative) 13 3 108 105 105 125 102 (compar- ative) 14 4 106 110 109 129 107 (inven- tive) 15 5 103 105 107 130 100 (compar- ative) 16 6 107 126 112 154 105 (inven- tive) 17 7 105 112 105 129 98 (compar- ative) 18 8 114 119 111 136 102 (inven- tive) 19 9 116 108 107 143 108 (compar- ative) 20 10 115 114 108 159 111 (inven- tive)

[0168] The rebound elasticity at 60° C., the loss factor tan δ at 60° C. from the temperature-dependent dynamic-mechanical measurement as well as the tan δ maximum and the modulus difference G′ between low and high strain from the strain-dependent dynamic-mechanical measurement are indicators for the rolling resistance in the tire. The loss factor tan δ at 0° C. is an indicator for the wet slip resistance of the tire.

[0169] As can be seen from Table 4, all vulcanizates containing functionalized diene rubbers are characterized by improved values for the wet grip indicator and the rolling resistance indicators. The vulcanizates from the inventive examples 14, 16, 18 and 20 have better properties than the vulcanizates from the corresponding examples 13, 15, 17 and 19, in which styrene-butadiene rubbers were used which were only reacted with cyclic anhydrides.