Methanol-terminated polymers containing silane

Abstract

The present invention relates to polymers functionalized by terminal groups, where these have, at the chain end, a silane-containing carbinol group of the formula (I) ##STR00001## where R.sup.1, R.sup.2, R.sup.3, R.sup.4 are identical or different and are H, alkyl moieties, cycloalkyl moieties, aryl moieties, alkaryl moieties and aralkyl moieties, where these can comprise heteroatoms such as O, N, S, Si, A is a divalent organic moiety which can comprise, alongside C and H, heteroatoms such as O, N, S, Si.

Claims

1. Polymers functionalized by terminal groups, the polymers comprising, at a chain end, a silane-containing carbinol terminal group of the formula (I) ##STR00019## or a metal salt thereof of the formula (II) ##STR00020## where R.sup.1, R.sup.2, R.sup.3, R.sup.4 are identical or different and are H, alkyl moieties, cycloalkyl moieties, aryl moieties, alkaryl moieties and aralkyl moieties, where these optionally comprise heteroatoms selected from O, N, S, and Si, A is a divalent organic moiety optionally comprising heteroatoms selected from O, N, S, and Si, n is an integer from 1 to 4, and M is a metal or semimetal of valency from 1 to 4, wherein the polymers are diene polymers or diene copolymers of dienes and vinylaromatic monomers.

2. The polymers functionalized by terminal groups according to claim 1, wherein M is Li, Na, K, Mg, Ca, Fe, Co, Ni, Al, Nd, Ti, Si, or Sn.

3. The polymers functionalized by terminal groups according to claim 1, wherein the diene polymer is a polybutadiene, a polyisoprene, a butadiene-isoprene copolymer, a butadiene-styrene copolymer, an isoprene-styrene copolymer or a butadiene-isoprene-styrene terpolymer.

4. Polymers functionalized by terminal groups, the polymers comprising diene polymers or diene copolymers of dienes and vinylaromatic monomers functionalized with functionalization reagent comprising one or more 1-oxa-2-silacycloalkanes, and the terminal groups are of the formula (I) and/or (II) ##STR00021## where R.sup.1, R.sup.2, R.sup.3, R.sup.4 are identical or different and are H, alkyl moieties, cycloalkyl moieties, aryl moieties, alkaryl moieties and aralkyl moieties, where these optionally comprise heteroatoms selected from O, N, S, and Si, A is a divalent organic moiety optionally comprising heteroatoms selected from O, N, S, and Si, n is an integer from 1 to 4, and M is a metal or semimetal of valency from 1 to 4.

5. The polymers functionalized by terminal groups according to claim 4, wherein the 1-oxa-2-silacycloalkanes are compounds of the general formula (III) ##STR00022## where R.sup.1, R.sup.2, R.sup.3, R.sup.4 are identical or different and are H, alkyl moieties, cycloalkyl moieties, aryl moieties, alkaryl moieties and aralkyl moieties, where these optionally comprise heteroatoms selected from O, N, S, and Si, and A is a divalent organic moiety optionally comprising heteroatoms selected from O, N, S, and Si.

6. The polymers functionalized by terminal groups according to claim 5, wherein the polymers have average molar masses (number average) of 10,000 to 2,000,000 g/mol.

7. The polymers functionalized by terminal groups according to claim 6, wherein the polymers have glass transition temperatures of 110 C. to +20 C.

8. The polymers functionalized by terminal groups according to claim 7, wherein the polymers have Mooney viscosities [ML 1+4 (100 C.)] of 10 to 200.

9. A process for producing the polymers functionalized by terminal groups according to claim 1, the process comprising functionalizing reactive polymer chain ends of diene polymers or diene copolymers of dienes and vinylaromatic monomers with one or more 1-oxa-2-silacycloalkanes (functionalization reagents).

10. The process according to claim 9, further comprising functionalizing the polymers after conclusion of polymerization, wherein the 1-oxa-2-silacycloalkanes are compounds of the general formula (III) ##STR00023## where R.sup.1, R.sup.2, R.sup.3, R.sup.4 are identical or different and are H, alkyl moieties, cycloalkyl moieties, aryl moieties, alkaryl moieties and aralkyl moieties, where these optionally comprise heteroatoms selected from O, N, S, and Si, and A is a divalent organic moiety optionally comprising heteroatoms selected from O, N, S, and Si.

11. The process according to claim 9, further comprising using an excess of the functionalization reagents.

12. The process according to claim 9, further comprising using stoichiometric amounts or substoichiometric amounts of the functionalization reagents.

13. The process according to claim 9, wherein the process comprises functionalizing the polymers with 0.005 to 2% by weight of the functionalization reagents based on the amount of polymer having reactive polymer chain ends.

14. The process according to claim 9, further comprising adding coupling reagents for reaction with the reactive polymer chain ends.

15. Vulcanizable rubber compositions comprising the polymers according to claim 1, and one or more of antioxidants, oils, fillers, rubbers and/or rubber auxiliaries.

16. Vulcanizable rubber compositions comprising polymers functionalized by carbinol terminal groups of the formula (I) ##STR00024## or metal salts thereof of the formula (II) ##STR00025## where R.sup.1, R.sup.2, R.sup.3, R.sup.4 are identical or different and are H, alkyl moieties, cycloalkyl moieties, aryl moieties, alkaryl moieties and aralkyl moieties, where these optionally comprise heteroatoms selected from O, N, S, and Si, A is a divalent organic moiety optionally comprising heteroatoms selected from O, N, S, and Si, n is an integer from 1 to 4, M is a metal or semimetal of valency from 1 to 4, and wherein the polymers are diene polymers or diene copolymers of dienes and vinylaromatic monomers.

17. The polymers functionalized by terminal groups according to claim 6, wherein the average molar masses are 100,000 to 1,000,000 g/mol.

18. The polymers functionalized by terminal groups according to claim 7, wherein the glass transition temperatures are 110 C. to 0 C.

19. The polymers functionalized by terminal groups according to claim 8, wherein the Mooney viscosities are from 30-150 Mooney units.

Description

EXAMPLES

Example 1a

Synthesis of Styrene-Butadiene Copolymer (Comparative Example)

(1) The following were charged to an inertized 20 L reactor: 8.5 kg of hexane, 1125 g of 1,3-butadiene, 375 g of styrene, 28 mmol of 2,2-bis(2-tetrahydrofuryl)propane and also 10 mmol of butyllithium, and the contents were heated to 70 C. The mixture was polymerized for 1 h at 70 C. with stirring. The rubber solution was then discharged, and stabilized by adding 3 g of Irganox 1520 (2,4-bis(octylthiomethyl)-6-methylphenol) and the solvent was removed by steam-stripping. The rubber crumb was dried in vacuo at 65 C.

(2) Vinyl content (by IR spectroscopy): 51.5% by weight; styrene content (by IR spectroscopy): 24.7% by weight; glass transition temperature (DSC): 16 C.; number-average molar mass M.sub.n (GPC, PS standard): 242 kg/mol; M.sub.w/M.sub.n: 1.30; Mooney viscosity (ML1+4 at 100 C.): 71 MU

Example 1b

Synthesis of Silane-Containing Carbinol-Terminated Styrene-Butadiene Copolymer (According to the Invention)

(3) The following were charged to an inertized 20 L reactor: 8.5 kg of hexane, 1125 g of 1,3-butadiene, 375 g of styrene, 28 mmol of 2,2-bis(2-tetrahydrofuryl)propane and also 10 mmol of butyllithium, and the contents were heated to 70 C. The mixture was polymerized for 1 h at 70 C. with stirring. 11 mmol (1.43 g) of 2,2-dimethyl-1-oxa-2-silacyclohexane were then added, and the reactor contents were heated to 70 C. for a further 20 min. The rubber solution was then discharged, and stabilized by adding 3 g of Irganox 1520, and the solvent was removed by steam-stripping. The rubber crumb was dried in vacuo at 65 C.

(4) Vinyl content (by IR spectroscopy): 51.2% by weight; styrene content (by IR spectroscopy): 24.8% by weight, glass transition temperature (DSC): 15 C.; number-average molar mass M.sub.n (GPC, PS standard): 261 kg/mol; KIM: 1.17; Mooney viscosity (ML1+4 at 100 C.): 73 MU

Example 1c

Synthesis of Silane-Containing Carbinol-Terminated Styrene-Butadiene Copolymer (According to the Invention)

(5) The following were charged to an inertized 20 L reactor: 8.5 kg of hexane, 1125 g of 1,3-butadiene, 375 g of styrene, 28 mmol of 2,2-bis(2-tetrahydrofuryl)propane and also 10.5 mmol of butyllithium, and the contents were heated to 70 C. The mixture was polymerized for 1 h at 70 C. with stirring. 11.6 mmol (1.69 g) of 2,2,4-trimethyl-1-oxa-4-aza-2-silacyclohexane were then added, and the reactor contents were heated to 70 C. for a further 20 min. The rubber solution was then discharged, and stabilized by adding 3 g of Irganox 1520, and the solvent was removed by steam-stripping. The rubber crumb was dried in vacuo at 65 C.

(6) Vinyl content (by IR spectroscopy): 51.3% by weight; styrene content (by IR spectroscopy): 25.4% by weight, glass transition temperature (DSC): 17 C.; number-average molar mass M.sub.n (GPC, PS standard): 233 kg/mol; M.sub.w/M.sub.n: 1.18; Mooney viscosity (ML1+4 at 100 C.): 69 MU

Examples 2a-c

Rubber Compositions

(7) Tyre tread rubber compositions were produced, comprising the styrene-butadiene copolymer from Example 1a as comparative example (rubber composition 2a), and also the silane-containing carbinol-terminated styrene-butadiene copolymers of the invention from Example 1b and 1c (rubber compositions 2b and 2c). Table 1 lists the constituents. The rubber compositions (without sulphur and accelerator) were produced in a 1.5 L kneader. The sulphur and accelerator constituents were then admixed on a roll at 40 C.

(8) TABLE-US-00001 TABLE 1 Constituents of tyre tread rubber compositions (data in phr: parts by weight per 100 parts by weight of rubber) Comparative Inventive Inventive Example Example Example 2a 2b 2c Styrene-butadiene copolymer from Example 1a 70 0 0 Silane-containing carbinol-terminated styrene-butadiene copolymer from Example 1b 0 70 0 Silane-containing carbinol-terminated styrene-butadiene copolymer from Example 1c 0 0 70 High-cis-content polybutadiene (BUNA CB 24 from Lanxess Deutschland GmbH) 30 30 30 Silica (Ultrasil 7000) 90 90 90 Carbon black (Vulcan J/N 375) 7 7 7 TDAE oil (Vivatec 500) 36.3 36.3 36.3 Processing aid (Aflux 37) 3 3 3 Stearic acid (Edenor C 18 98-100) 1 1 1 Antioxidant (Vulkanox 4020/LG from Lanxess Deutschland GmbH) 2 2 2 Antioxidant (Vulkanox HS/LG from Lanxess Deutschland GmbH) 2 2 2 Zinc oxide (Rotsiegel zinc white) 2 2 2 Wax (Antilux 654) 2 2 2 Silane (Si 69 from Evonik) 7.2 7.2 7.2 Diphenylguanidine (Vulkacit D/C from Lanxess Deutschland GmbH) 2.2 2.2 2.2 Sulfenamide (Vulkacit NZ/EGC from Lanxess Deutschland GmbH) 1.6 1.6 1.6 Sulfur (90/95 Chancel ground sulfur) 1.6 1.6 1.6 Sulfonamide (Vulkalent E/C) 0.2 0.2 0.2

Examples 3a-c

Vulcanizate Properties

(9) The tyre tread rubber compositions of Examples 2a-c according to Table 1 were vulcanized at 160 C. for 20 minutes. The properties of the corresponding vulcanizates are listed as Examples 3a-c in Table 2.

(10) TABLE-US-00002 TABLE 2 Vulcanizate properties Comparative Inventive Inventive Example Example Example 3a 3b 3c Styrene-butadiene copolymer in vulcanizate: Styrene-butadiene copolymer from Example 1a X Silane-containing carbinol-terminated styrene-butadiene copolymer from Example 1b X Silane-containing carbinol-terminated styrene-butadiene copolymer from Example 1c X Vulkanizate properties: Resilience at 23 C. [%] 28 29.5 30 Reslilience at 60 C. [%] 50.5 55.5 55.5 tan maximum (MTS amplitude sweep at 1 Hz, 60 C.) 0.193 0.177 0.178 tan at 0 C. (dynamic damping at 10 Hz) 0.291 0.324 0.326 tan at 60 C. (dynamic damping at 10 Hz) 0.120 0.108 0.113 Elongation at break (S2 test specimen) [%] 428 428 428 Tensile stress at break (S2 test specimen) [MPa] 18.3 19.5 19.3 Abrasion (DIN 53516) [mm.sup.3] 95 90 84

(11) Tyre applications require low rolling resistance, and this is present if the values measured in the vulcanizate are high for rebound resilience at 60 C. and low for tan in dynamic damping at high temperature (60 C.) and low for tan maximum in the amplitude sweep. As can be seen from Table 2, the vulcanizates of Inventive Examples 3b and 3c feature high rebound resilience at 60 C., low tan in dynamic damping at 60 C. and low tan maximum in the amplitude sweep.

(12) Tyre applications also require high wet skid resistance, and this is present if the vulcanizate has high tan in dynamic damping at low temperature (0 C.). As can be seen from Table 2, the vulcanizates of Inventive Examples 3b and 3c feature high tan in dynamic damping at 0 C.

(13) Tyre applications moreover require high abrasion resistance. As can be seen from Table 2, the vulcanizates of Inventive Examples 3b and 3c feature low DIN abrasion.