Methanol-terminated polymers containing ether

Abstract

The present invention relates to polymers functionalized by terminal groups that have, at the chain ends thereof, an ether-containing group of the formula (V)
[O-A-O.sup.].sub.nX.sup.n+(V)
where A is a divalent organic moiety, and X is either H, and n=1, or X is a metal and n is an integer of 1 to 4.

Claims

1. Polymers functionalized by terminal groups, wherein: the polymers comprise diene polymers or diene copolymers obtained via copolymerization of dienes with vinylaromatic monomers, and functionalization with one or more cycloperoxides; the polymers comprise, at chain ends of the polymer chains, an ether-containing group of the formula (V)
[O-A-O.sup.].sub.nX.sup.n+(V) where: A is a divalent organic moiety, and X is M, n is an integer from 1 to 4, and M is a metal or semimetal having a valency of 1 to 4; and the average molar masses of the polymers are from 100,000 to 1,000,000 g/mol, the glass transition temperatures of the polymers are from 110 C. to 0 C., and the Mooney viscosities [ML 1+4 (100 C.)] of the polymers are from 30 to 150 Mooney units.

2. The polymers according to claim 1, wherein the ether-containing group of the formula (V) comprises a metal salt according to the formula (II) ##STR00005## where A is a divalent organic moiety comprising C and H, and M is Li, Na, K, Mg, Ca, Fe, Co, Ni, Al, Nd, Ti, Si, or Sn.

3. The polymers according to claim 1, wherein A is a divalent organic moiety comprising C, H and optionally heteroatoms selected from the group consisting of O, N, S, and Si.

4. The polymers 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.

5. The polymers according to claim 1, wherein the cycloperoxides are compounds of the general formula (III) ##STR00006## where A is a divalent organic moiety comprising C and H.

6. A process for producing the polymers according to claim 1, the process comprising: polymerizing the diene monomers or diene monomers and the vinylaromatic monomers to produce polymers having reactive polymer chain ends; and terminating the polymer chains by adding one or more cycloperoxides as functionalization agents to the polymers having reactive polymer chain ends to react the cycloperoxides with the reactive chain ends.

7. The process according to claim 6, further comprising adding the functionalization reagents after polymerization of the polymers.

8. The process according to claim 6, further comprising adding an excess of the functionalization reagents.

9. The process according to claim 8, wherein the amount of the functionalization reagents, based on the amount of polymer having reactive polymer chain ends, is 0.005 to 2% by weight.

10. The process according to claim 8, further comprising adding coupling reagents prior to, along with, or after adding the one or more peroxides to the polymers having reactive polymer chain ends.

11. The process according to claim 6, further comprising adding stoichiometric amounts or a substoichiometric amount of the functionalization reagents.

12. The process according to claim 11, wherein the amount of the functionalization reagents, based on the amount of polymer having reactive polymer chain ends, is 0.005 to 2% by weight.

13. A process for producing vulcanizable rubber compositions comprising the polymers functionalized by terminal groups according to claim 1, the process comprising mixing the polymers functionalized by terminal groups according to claim 1 with a vulcanizing agent.

14. Vulcanizable rubber compositions obtained according to the process of claim 13, wherein the composition comprises rubbers and/or rubber auxiliaries, and the rubber auxiliaries comprise antioxidants, oils, and/or fillers.

15. A method for producing moldings, the method comprising producing moldings from the vulcanizable rubber compositions according to claim 13.

16. Moldings obtained by the method according to claim 15, the moldings comprising a molding selected from the group consisting of cable sheathing, hoses, drive belts, conveyor belts, roll coverings, shoe soles, sealing rings and damping elements.

17. A method for producing at least tire treads of tires, the method comprising producing at least the tire treads from the vulcanizable rubber compositions according to claim 13.

18. Tires obtained by the method according to claim 17.

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)propene 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 Ether-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, 29 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. Thereafter, 10 mmol (1.74 g) of 3,3,5,7,7-pentamethyl-1,2,4-trioxepane were added and the contents of the reactor were heated at 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): 51.3% by weight; styrene content (by IR spectroscopy): 24.8% by weight; glass transition temperature (DSC): 16 C.; number-average molar mass M.sub.n (GPC, PS standard): 254 kg/mol; M.sub.w/M.sub.n: 1.20; Mooney viscosity (ML1+4 at 100 C.): 73 MU

Example 1c: Synthesis of Ether-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, 29 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. Thereafter, 10 mmol (2.64 g) of 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxononane were added (in the form of 41% solution in isoparaffinic hydrocarbons) and the contents of the reactor 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): 51.4% 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): 257 kg/mol; M.sub.w/M.sub.n, 1.20; Mooney viscosity (ML1+4 at 100 C.): 75 MU

Examples 2a-c: Rubber Compositions

(7) Tyre tread rubber compositions were produced which comprise the styrene-butadiene copolymer from Example 1a as comparative example (rubber composition 2a), and also the ether-containing carbinol-terminated styrene-butadiene copolymers according to 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) Com- In- In- parative ventive ventive example example example 2a 2b 2c Styrene-butadiene copolymer from 70 0 0 Example 1a Ether-containing carbinol-terminated 0 70 0 styrene-butadiene copolymer from Example 1b Ether-containing carbinol-teminated 0 0 70 styrene-butadiene copolymer from Example 1c High-cis-content polybutadiene 30 30 30 (BUNA CB 24 from Lanxess Deutschland GmbH) 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 2 2 2 Lanxess Deutschland GmbH) Antioxidant (Vulkanox HS/LG from 2 2 2 Lanxess Deutschland GmbH) 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 2.2 2.2 2.2 from Lanxess Deutschland GmbH) Sulphenamide (Vulkacit NZ/EGC 1.6 1.6 1.6 from Lanxess Deutschland GmbH) Sulphur (90/95 ground sulphur, Chancel) 1.6 1.6 1.6 Sulphonamide (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 have been listed as Examples 3a-c in Table 2.

(10) TABLE-US-00002 TABLE 2 Valcanizate properties Comparative Inventive Inventive example example example 3a 3b 3c Styrene-butadiene copolymer in vulcanizate: Styrene-butadiene copolymer X from Example 1a Ether-containing carbinol- X terminated styrene-butadiene copolymer from Example 1b Ether-containing carbinol- X terminated styrene-butadiene copolymer from Example 1c Vulcanizate properties: Rebound resilience 28 30 30 at 23 C. [%] Rebound resilience 50.5 54 54 at 60 C. [%] tan maximum (MTS 0.193 0.165 0.175 amplitude sweep at 1 Hz, 60 C.) tan at. 0 C. (dynamic 0.291 0.342 0.346 damping at 10 Hz) tan at 60 C. (dynamic 0.120 0.111 0.108 damping at 10 Hz) Elongation at break (S2 test 428 410 423 specimen) [%] Tensile stress at break 18.3 18.7 18.9 (S2 test specimen) [MPa] Abrasion (DIN 53516) [mm.sup.3] 95 92 90

(11) Tyre applications need low rolling resistance, and this is present if the values measured in the vulcanizate we 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 in Table 2, the vulcanizates of Examples 3b and 3c according to the invention 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 need high wet skid resistance and this is present when the vulcanizate has a high tan value in dynamic damping at low temperature (0 C.). As can be seen in Table 2, the vulcanizates of Examples 3b and 3c according to the invention feature a high tan value in dynamic damping at 0 C.

(13) Tyre applications also need high abrasion resistance. As can be seen from Table 2, the vulcanizates of Examples 3b and 3c according to the invention feature low DIN abrasion.